November 2017: An Unusual Month

 

IMG_7159b.jpg

Just after sunset on November 15th, a pleasant day with a high near 60 degrees.

While November normally sees the greatest drop in temperature of the three transition months of autumn, this year November was more like a fall transition month stuck in reverse.

If one divides the month into three ten-day periods, the first ten days was the coolest period and the last 10 days of the month was the warmest. The first 10-days of November had an average daily mean of 41.6 degrees, which was 6.6 degrees below normal. The last ten days of November had an average daily mean of 47.2 degrees, which was 8.4 degrees above normal.

There is an unexpected November scenario for you.

November Temperature Specifics: For November as a whole, the average daily high was 57 and the average low 33. This resulted in an average daily mean of 45 degrees, which was 1.5 degrees above normal.

The coldest reading of the month at the airport was 15 degrees on November 22nd. With a high of 44, the resulting daily mean was 30 degrees, also the coldest of the month.

The next day, the 23rd, Thanksgiving Day, was pleasant with a high in the upper 60s and the low around the freezing mark.

The day after Thanksgiving, the 24th,  the temperature hit 77 at the Lawrence Airport, the warmest reading of the month. With a low of 43, the daily mean was 60 degrees, also the warmest of the month. This was a rather incredible 30 degrees warmer than the daily mean temperature of just two days previous.

In fact, November 24th saw record warmth for the date throughout the region including at Topeka (79; previous record 76), Concordia (83; previous record 73), St Joseph (75; previous record 72) and Wichita (76; previous record 70).

Also instructive of the ‘reverse’ temperature trend in November, all ten days of the month that reached 60 or warmer occurred from the 15th to the 30th. On the other hand, five of the six days that recorded highs in the 40s occurred during the first half of the month.

Wind: Strong and gusty winds occurred on several days as a series of dry fronts swept across the region, especially during the last half of the month. The windiest day was the 18th with a peak gust out of the northwest of 42 MPH. Two days later, on the 20th, south winds gusted to 40 MPH. The day after that, northwest winds gusted to 40 MPH. Close behind, toward the end of the month, south winds gusted to 39 MPH on the 28th.

I don’t know about everyone else, but all the back and forth wind left a bumper crop of Pin Oak leaves surrounding my humble abode this season.

Barometric Pressure: In the fall, winter and spring months, it is sometimes interesting and instructive to note the barometric pressure. So, for any barometer watchers out there, the lowest barometric pressure of November was 29.37 inches on the 18th, which was also the day with the strongest winds. The highest barometric pressure was 30.42 inches on the 10th, the second coldest day of the month and also the day with the coldest high temperature (42 degrees).

Humidity: Very changeable humidity also occurs in the fall, winter and spring and can be indicative of weather trends. The three days of highest average humidity were all in the first half of November. Conversely, the three days of lowest average humidity were all in the last half of the month. The last 10 days of the month were quite dry with all of the three driest readings. The lowest humidity reading of the month was 21 percent on both the 21st and 26th. Close behind was a minimum humidity of 22 percent on the 30th and 23 percent on the 29th.

Precipitation: Rainfall in November was nothing to shout or write home about. Only 0.12 inches was recorded at the Lawrence Airport. The average from our reporting rain gage sites across the city was 0.18 inches.  Normal for November is 2.18 inches.

The only wetting rain of the month occurred on November 11th. On that day, a tenth of an inch of drizzle and small-dropped rain fell on our Veterans Day parade.

The last rain of any real significance dates back to October 21st and 22nd, when well over two inches fell.  With only negligible rainfall since, most of which fell on Veterans Day, we were 5 ½ weeks into a relative dry spell as of the end of November.

Calendar year precipitation: At this point, nothing is going to stop our well above normal precipitation for the calendar year. While November’s contribution was not significant this year, our six to seven regularly reporting precipitation sites across the city are up to an average of 44.24 inches for the year to date. Normal through the end of November is 37.08 inches.

Looking ahead: The one-month outlook issued by the NWS on November 30th forecasted a moderately strong likelihood of below normal precipitation for December. The temperature forecast for our area is non-committal – equal chances of above or below normal.

The average daily high and low for December is 42 and 21. December averages 1.47 inches of precipitation, including about five inches of average snowfall (that fluffy white stuff, in case you’ve forgotten).

dk

 

A Mild and Dry Last 8 Days of November

November 23rd – 30th.

The average mean temperature during the last eight days in November at the Lawrence Airport was 50.5, which was 12.1 degrees above normal.

The average high for the period was 65 and the average low 35.  At my residence in southwest Lawrence, the average high was also 65 and the average low 40.  This is pretty consistent with recent history where I find that my high temperatures agree closely with the airport values but my low temperatures run about five degrees warmer than the airport on average.  This is easily explained by the fact that the airport is located on the Kansas River flood plain where cold drains and pools at night if winds are relatively light.  The difference in low temperatures is far greater on clear and calm nights.  In these situations, the low at the airport is anywhere from 5 to 10 degrees cooler than what I register at my residence in town.  On cloudy and/or windy nights, low temperatures will be similar to a couple of degrees cooler at the airport.

Humidity was low during the period with generally breezy to windy conditions.

IMG_7246.jpg

Thanksgiving Day, November 23rd, just before sunset on the Baker Wetlands.  Temperature of 65 degrees with light winds and just some high clouds.

upaCNTR_500-1.gif

500 MB Thanksgiving morning, November 23rd. 

 

IMG_7253.jpg

November 24th – Norman the dog at the east shore of Perry Lake at 4 PM.  This was the warmest day of the month with a high of 77 in Lawrence.  Record high temperatures for the date in the mid to upper 70s occurred throughout eastern Kansas with record high lower 80s in central Kansas.  By this time, however, a dry cold front had just moved through at Perry Lake and temperatures were beginning to cool a bit on breezy northwest winds, as can be seen by the wave action on the lake.

IMG_7276

November 25th, 4:30 PM:  Once again on the east shore of Perry Lake – a fine day with clear skies, light winds and a temperature of about 60.

upaCNTR_500-2.gif

500 MB Saturday morning, November 25th.

IMG_0623a.jpg

November 26th at 3 PM:  Trail through the tall grass at the Topeka Audubon Bird Sanctuary near the upper east arm of Perry Lake.  A guy working on the trials said he saw a golden eagle by the lake (the lake visible in the background).   It was another mild and dry day with the temperature in the upper 60s.

IMG_7281.jpg

November 27th:  A sunset walk on public lands just east of Perry Lake.  Again the temperature was in the mid 60s with light south breezes, which had brought up somewhat higher humidity.

upaCNTR_500-3.gif

500 MB Monday morning, November 27th.  A stout shortwave broke the high pressure ridge and pushed into California bringing some much-needed rain and high elevation snow to central sections of the state.  Not much for southern sections of the state, though.  

upaCNTR_500-5.gif

500 MB Tuesday evening, November 28th.  The shortwave has become a closed low trekking across just to our south.  It brought some decent rain up to around a half inch as far north as Medicine Lodge, Wichita and far southeast Kansas on the 29th, but just some cloudiness to our area (below). 

IMG_7287a.jpg

November 29th, 3:50 PM – A thick overcast but all the rain missed to our south moving across far southern Kansas and northern Oklahoma.  This is looking northwest from just north of Baldwin City, at the Signal Oak Historical Marker.   Just to the north of this location is The Baldwin Woods, part of which can be seen to the center right in this photo.  From the Jayhawk Audubon Website:  “The Baldwin Woods is considered one of the westernmost examples of an eastern deciduous forest in the state.  With mature oaks and hickories and a well-developed understory, the area is quite distinct from other wooded areas in the county.”

IMG_7291a.jpg

November 29th at 4:27 PM – Some interesting clouds and late day clearing about 3 miles southwest of Lone Star Lake – specifically, looking west off of E400 Rd just north of Highway 56.  The area is known as the Globe Prairie and was home to Douglas County’s last Prairie Chickens.  It is still a good area for open country bird watching as some of the largest tracts of native grassland in Douglas County are in this area around the hamlet of Globe. 

IMG_7296a.jpg

November 29th, 4:36 PM.  Looking west a short distance north of the above photo.  The temperature was in the mid 50s at this time. With the dearth of rainfall over the last 5 weeks (0.10 to 0.20 inches), the surface of the ground is dry and the gravel roads very dusty.

IMG_7312.jpg

November 30th at 4:10 PM:  From the boat ramp at the Rock Creek arm of Clinton Lake.  My approach disturbed the gulls, which in turn awakened the pelicans perched on a snag.   Sunny skies, light winds and temperatures in the mid to upper 50s closed out the month.

IMG_7327a.jpg

November 30th, 4:30 PM.  Saw this guy perched on the power supply to a small farmhouse southwest of Clinton Lake.  Took this out the passenger side window of the vehicle.

IMG_7328a.jpg

He was either sharpening his beak or finishing a meal, but I didn’t see a carcass.

IMG_7329a.jpg

Pretty bird!

$$

 

 

 

 

Week in Review: Dribbles of Rain, Lots of Wind and Roller Coaster Temperatures

November 13th – 22nd:  A series of moisture-starved cold fronts pushed across the area during the past week or so as a west to northwest upper-level flow regime predominated.

Since the Veterans Day drizzle event on the 11th, just four hundredths of an inch has registered at the Lawrence Airport.  Within Lawrence our manual observers averaged seven hundredths, with .05″ on the 14th-15th and 0.02″ on the 18th.  With the first ten days of the month essentially dry, the monthly total at the airport stands at 12 hundredths, with the city coming in at 18 hundredths.  The few dribbles of rain were no match for the strong and gusty winds over the last few days, with surface ground conditions now rather dry and dusty following our wet October.   This stands to reason, as the last precipitation of significance ended exactly one month ago, on the morning of October 22nd, when 2.32 inches fell in 24 hours at the airport and 2.41 inches across the city.  Since then, only the above mentioned feeble amounts of November have occurred.

Temperatures during the past 10 days (13th to the 22nd) were quite variable, as is typical in this transitional time of year.  The warmest day was Friday the 17th with a high of 73 and low of 51, bringing a daily mean temperature that was 19 degrees above normal.  On the cool side, Wednesday, the 22nd, came in with the coldest reading of the season so far with a low of 15 at the Lawrence Airport, while a low of 20 degrees was recorded on my home weather station in southwest Lawrence from about 6:45 to 7:45 AM.  The coolest high temperature of the period was also Wednesday the 22nd with a high of 44 at the airport and on my home weather station as well.

Perhaps the big story during the past week or so has been the gusty winds that have both preceded and followed several modified Canadian cold fronts with air mainly of northern Pacific origin (as opposed to winter-like arctic cold fronts which have yet to penetrate the local area).

Northwest winds were quite strong on Saturday, the 18th, with maximum sustained winds of 33 MPH and a peak gust to 42 MPH.   This was almost matched by south winds  on Monday, the 20th, sustained up to 30, gusting to 40 MPH.   Needless to say, this was followed by quite breezy north winds behind another cold front on Tuesday, the 21st, when north winds again gusted to 40 MPH with maximum sustained winds of 32 MPH.  If all this back and forth windiness has not left piles of leaves around your humble abode by this point (as they have at my place),  then probably nothing much will.

The dry west to northwest flow regime looks to continue the rest of the month.  Warmer air will start to advect into Kansas as early as tonight, the 22nd, as winds again turn light out of the south, likely prevent subfreezing temperatures from occurring.   Passing dry cold fronts are expected to bring mainly a glancing blow to our area, mainly passing by to our north and east, as a ridge of high pressure aloft to our west dominates the local region.  This should result in milder temperatures and less wind from passing dry cold fronts over the next week than what we have had over the last several days.

In short, dry and generally pleasant conditions for late November can be expected at least into early next week and perhaps for the rest of the month.

IMG_7153a

Wednesday, November 15th, 5:09 PM:  A pleasant sunset at Clinton Lake.  The temperature was in the mid 50s at the time, having maxed out near 60.   Winds were northwest on this day up to 28 MPH following the passage of an early morning cold front.  Before the front moved in, showers dropped five hundredths of an inch of rain fell across town in the wee hours of the morning around 2 AM.

IMG_7166.jpg

Nine minutes after the previous image, I snapped this zoom of the western horizon revealing that our turkey vulture friends are still out on their favorite lake-view perches at Clinton Lake.

IMG_7174a.jpg

At the Baker Wetlands on Thursday, November 16th at 5:42 PM:  This heron is patiently waiting in locally calm waters for an unwary fish.  This was a pleasant day with a high of 57, low of 28 and light southeast winds.

IMG_7195a.jpg

At 5:08 PM, the sun has set behind a bank of lower clouds in the distant west as a flock of Canada Geese decides on a roosting area for the night out at the Baker Wetlands.

IMG_7206a.jpg

Friday, November 17th, at the north end of Perry Lake.  This was the warmest day of the month so far with a high of 73.  Here, at 4:55 PM, it is still 70 degrees as the sun sets behind dense cirrus on the horizon.  Note also the streaks of cirrus in the strong westerly jet-stream winds aloft.  Commercial aircraft are also leave their ‘con trails’ aloft over ‘flyover country’ at sunset.

 

IMG_7223a

By 5:17 PM, 22 minutes after the above image, the sun was reflecting off the base of some alto stratus that had developed over the last 20 minutes or so ahead of an approaching upper trough and cold front.

upaCNTR_250.gif

And here is that upper trough and jet stream on the evening of the 17th.  Notice the strong 150 Kt + jet max over Colorado with a 135 Kt max extending eastward to Topeka.  This will generate some alto status, alright!  Not to mention who knows what else..

upaCNTR_700.gif

Here is the incoming trough at 700 MB (about 10,000 ft).

 

ruc00hr_sfc_wind.gif

At the surface, a low is over Kansas with a cold front knocking on our door and pushing into northwest Kansas by this time (8 PM on the 17th).  Note the very closely packed isobars across Colorado and Utah marking an area of strong northwest winds that were to effect us the following day.

upaCNTR_250-1.gif

Saturday morning, November 18th, the upper trough moves across with the jet max sinking southward.

upaCNTR_700-1.gif

Here is the deepening700 MB trough with some moisture and colder air moving in on strong north winds.

upaCNTR_850-1.gif

At 850 MB (5000 ft) lots of moisture and very strong north winds Saturday morning with the trough at this level having already moved through most of Kansas.  A little light rain fell with this moisture before the strong winds hit.

IMG_7229a.jpg

Just before sunset Saturday, November 18th, 4:28 PM, at Deer Creek Wildlife Area just northwest of Clinton Lake.   The daytime high was 52 as cold air pushed in behind the early morning cold front.  A couple hundredths of an inch of rain fell across the area between about 8 and 9 AM behind the front.  Skies gradually cleared during the afternoon as drier air moved in.  Here, some instability cumulous are dissipating with the loss of daytime heating.  Winds were very strong and gusty out of the northwest all day with a maximum gust of 42 MPH at the Lawrence Airport.

IMG_7233a.jpg

Looking east at Deer Creek Wildlife Area at 4:30 PM, we see some lingering, ragged, dissipating cumulous as northwest winds gradually decrease.

IMG_7235a.jpg

At the west end of Clinton Lake, looking east, at 4:58 PM.  The dam can be seen in the distance, lit by the setting sun on the horizon (left center).

IMG_7240a.jpg

The sun sinks below the western horizon as seen from about a mile west of Clinton Lake at 5:11 PM Saturday, November 18th.  A very blustery day, winds averaged 16.2 MPH at the Lawrence Airport, an unusually high number for an entire 24-hour period.  Piles of leaves surrounded my residence by the end of the day.  Piles.  As winds died down, the low Sunday morning, the 19th, dropped to 23 at the Lawrence Airport and 27 at my residence in southwest Lawrence.

upaCNTR_250.gif

Tuesday evening, November 21st:  Splitting upper trough, with part driving straight south into Texas and part splitting off to the Great Lakes Region.  The result for the Lawrence area was a dry cold front passage bringing gusty northwest winds to 40 MPH.

ruc00hr_sfc_wind.gif

Surface map at midnight, Tuesday night, Nov 21st/22nd.  Strong surface high of modified pacific origin pushes over Kansas, bringing dying winds and temperatures rapidly dropping into the mid 20s Tuesday after sunset.

ruc00hr_sfc_wind-1.gif

By Wednesday morning, the surface high is centered right over eastern Kansas, allowing maximum radiational cooling.  The morning low was 15 at the Lawrence Airport, the coolest reading of the fall season so far and likely the entire month.

g13.2017326.0245_US_wv.jpg

Water vapor image at 8:45 PM Tuesday evening (Nov 21st) showing the upper trough that drove the latest cold front extending from Indiana to central Texas.  A ridge of high pressure aloft is out west over California.  An ‘atmospheric river’ of moisture extending from the subtropical Pacific to the Pacific Northwest has been bringing lots of rain to Washington and northern Oregon.

g13.2017326.1145_US_wv.jpg

By early Wednesday morning (5:45 AM CST) the split upper trough extends from the Virginias to east Texas.  The atmospheric river of moisture continues feeding into the Pacific Northwest, then rounds the corner over the upper ridge out west, crosses the Rockies and heads our way.  Of course, by the time the river of Pacific moisture crosses the northern Rockies, lower level moisture is completely wrung out.   The eastern front of the northern Rockies triggers a wave that brings some some enhanced cirrus, which then gradually thins as it heads southward across the plains.

upaCNTR_250.gif

Wednesday evening at Jet-stream level, the 250 MB chart shows the splitting upper trough to our east with the southern portion that was over eastern Texas 24 hours ago (above 250 chart) now over the western Gulf of Mexico.  The upper ridge out west is bringing record or near record warmth to much of the Pacific southwest over the Thanksgiving Holiday period.  This includes southern California where low to mid 90s were common today across the Los Angeles and San Diego region, even right along the coast!  Highs in the low 80s occurred today as far north as the Monterey Bay Area and Las Vegas.

upaCNTR_850.gif

At the 850 MB level (about 5,000 ft ASL) Wednesday evening.  Warmer air is moving in across Kansas, as can be seen with the warmer isotherm lines crossing the state perpendicular to the west to northwest wind flow.  Out west, an expensive high pressure area is over the inter-mountain region.  This is bringing an off-shore flow at this level and below along the southern California coast, resulting in the extreme warmth in that region.  Farther north, an atmospheric river of moist air originating from the subtropics continues to bring rain to the Pacific Northwest.

$$

Drizzle on your Parade

November 11th and 12th:

paradecrop_t640.jpg

From the Lawrence Journal World:  “Veterans on motorcycles ride down Massachusetts Street in the Veteran’s Day parade on Saturday, Nov. 11, 2017.”  Photo by Mike Yoder.

Veterans Day (Saturday, November 11th) brought the first widespread precipitation event of November as a ‘soaking drizzle’ fell across the area Saturday afternoon and evening.  When the measurable precipitation was done at about 9:30 PM, an average tenth of an inch of precipitation had accumulated across town, with individual amounts ranging from 0.07 to 0.13 inches.  At the Lawrence Airport, 0.08 inches was measured.  Temperatures were hovering in the mid 40s during the event with a light east breeze.  The high was 49, just before noon, and the low 35, resulting in a mean temperature that was four degrees below normal for the date.

Low-level ‘cold air advection’ on Sunday, the 12th, kept a low overcast across the region, though the sun made a few attempts to peer through at times around noon.  The high again reached 49 at about noon with a mid morning low of 45.   However, clearing shortly after sunset and subsequent radiational cooling allowed the temperature to drop to 31 at the Lawrence Airport by about 10 PM, resulting in a daily mean of five degrees below normal for the date.  The midnight to midnight range at my residence in southwest Lawrence was 50 and 37, averaging out to only 1.5 degrees below the normal daily mean of 45 degrees.

g13.2017315.2045_ICT_vis.jpg

Satellite image at 2:45 PM Saturday, during the height of the drizzle event. Low clouds blanket the area with band of higher clouds over the local area as well, making for a low-light day indeed, along with the drizzle.   

g13.2017315.2045_ICT_ir.jpg

Color Infrared image at the same time as the above visual image:  The layered clouds are clearly seen here with the low cloud tops at 0 degrees C (light orange) and mid to high level clouds in a band above (-10C to -30 degrees C cloud tops).    

250:12:00.gif

250 MB Chart (jet stream level) at 6 PM Saturday:  The upper wave over the plains states moves in, bringing enough lift for the drizzle.  Note the very strong jet streak over northeast Kansas of 110 knots, which helps provide lift as well.

top12:00.gif

The 6 PM Saturday Topeka weather balloon sounding data shows that the saturated layer was limited to below 700 MB (10,000 feet ASL) by this time, with mainly dry air above.  Thus the very light precipitation, as only this low-level moisture was lifted by the incoming wave, wringing out  mainly drizzle, mixed with a bit of small-dropped light rain.

850:12:00.gif

The Saturday evening 850 MB chart (about 5,000 feet ASL) shows the extensive moisture at this level over the local region with a weak trough also seen moving across Kansas.

700:12:00.gif

The Saturday evening 700 MB chart (about 10,000 ft ASL) clearly shows the mid-level wave traversing eastern Kansas.   However, the computer has mis-drawn the 0-degree Celsius isotherm at this level, as Topeka shows a -2C reading.  So, the solid blue line should dip south of Topeka, not swerve north.  Just goes to show you – computer analysis can be a bit goofy on these charts!

g13.2017316.2215_ICT_vis.jpg

Satellite image at 4:15 CST on Sunday, October 12th:  The clearing advanced almost but not quite to Lawrence by the last hour of the day.

IMG_7123a.jpg

The snags in the distance at Clinton Lake at 4:56 PM Sunday – 13 minutes before official sunset time.  Low overcast skies continued with just a hint of the advancing clearing seen in lighter skies along a strip above the northwest horizon.  So, under rather dark gray skies, I zoomed in on the mid-lake perches and west shore of the lake.  The turkey vultures are still hanging out on the perches, along with the occasional gull and pelican.  Some color is still vaguely seen on some of the west-shore trees, as well. 

$$

 

First 10 Days of November Cool, Mainly Cloudy and Dry

IMG_6981a.jpg

The Baker Wetlands on Sunday, November 5th:  Breaking up was hard to do, but low cloudiness  finally cleared during the afternoon of the 5th as a dry cool front pushed in from the north.  This was welcome relief following a long, dreary period of continual overcast skies since the 31st of October.  Time to get out and take a few photos, finally!

Temperatures during the first 10 days of November averaged a cool 6.6 degrees below normal, according to official readings taken at the Lawrence Airport.  Precipitation has been limited to a bit of light drizzle recorded at some manual city sites during the first few days of the month.

A low overcast deck that prevailed from the 1st through the 4th of the month finally cleared out during the afternoon of Sunday, November 5th, after a dry cold front pushed in.  Clear skies and cool temperatures prevailed behind the front on the 6th.   On the 7th, a fast, westerly jet stream flow aloft brought mid and high level cloudiness.  Wednesday, the 8th, brought clear skies and light winds.  The 9th was mostly sunny but with some thin high clouds.  The 10th had a broken high stratus deck at around 5000 feet most of the day.

The average high temperature during the first 10 days of November at the Lawrence Airport was 51 and the average low 32 (rounded to the nearest whole degree).   At my residence, near Clinton Parkway and Inverness, the average high was 50 (one degree cooler than the airport) and the average low 35 (three degrees warmer than the airport), ranging from a high of 57 on the 2nd to a low of 26 on the 10th.  Normal for the 10-day period as a whole is 61 and 36, though average temperatures drop about a half a degree daily this time of year.

As the numbers show, the deviation below normal so far in November has been determined more by the cool high temperatures than the overnight low readings.  However, lows have averaged about 4 degrees below normal, with half of the days during the period dipping into 20s at the official Lawrence climate site on the Kansas River floodplain.

The warmest temperature during the period at the airport was 57 on November 5th and the coolest was 23 on the morning of the 8th.

Only the second day of the month has had a mean temperature above normal, and it was only one degree above normal, at that.   This was also the warmest average day with a high of 56 and low of 45.  The coolest day was the 10th with a high of 41 and low of 25.  The 10th also recorded the greatest negative daily deviation with a mean temperature of 13 degrees below normal.

No precipitation has been recorded at the airport during the month.  Two of our manual rainfall sites across town recorded one hundredth of an inch from light drizzle on the 2nd, with other sites recording a trace.  Trace amounts were also recorded at some city sites on the 1st, 3rd and 4th of the month as light drizzle and mist drifted down at times from the persistent low overcast.

The airport site recorded ‘mist’ at times during this period, a non-precipitation aviation weather condition which occurs when the humidity is high and the visibility is recorded at 6 miles or less.  When the visibility drops to a half mile or less with high humidity, the aviation weather condition is recorded as ‘fog,’  which also occurred on a few mornings early in the month.

250:04:12.gif

At jet stream level (250 MB) on the morning of November 4th:  Splitting upper trough along the west coast with a ridge over Kansas and a strong jet stream flow.  Warm air aloft is trapping cool, low-level moist air over northeast Kansas, resulting in the persistent low cloudiness. 

top05:00.gif

Topeka upper air sounding on the evening of November 4th.  A strong inversion starting just below 900 MB extending to 850 MB traps cool, low-level moist air near the surface.  Dry air lies above the inversion until the jet stream flow brings some mid and high level moisture and clouds above about 500 MB.  Strong westerly winds aloft peak at 115 knots at about 250 MB.  

IMG_6973a.jpg

On the afternoon of the 5th, a cool, dry north breeze shunted the moist air southward allowing the sun to come out following five consecutive overcast days.  This seemed to be a good time to test the strangely sunlit, wind-blown waters.

IMG_6974a.jpg

But there is a bit too much wind to see any fish here..

IMG_6975.jpg

So time to fly to calmer waters..

IMG_6978b.jpg

Come on out, the water’s fine..

 

IMG_6985.jpg

Coots and ducks seemed to be enjoying the novel late afternoon sunshine on November 5th, though the temperature was about 50 and falling on the dry, late-day north breezes.

IMG_7013.jpg

Monday, the 6th, was blessed with more sunshine and a decent sunset at Clinton Lake.  Here, some coots swim slowly by in the foreground.   Low clouds were trying to push in from the south by late in the day, as seen here near the horizon, blocking the setting sun.   Temperatures were falling through the mid 40s at sunset.  The low clouds moved on in and held temperatures in the lower 40s after dark.

 

IMG_7026.jpg

Jet stream cirrus in the fast flow aloft reflected some color in the water, too.

upaCNTR_250-2

Jet stream level on Tuesday evening, November 7th, a mostly cloudy day with mid and high level overcast.  A very strong jet streak is over northeast Kansas ahead of a short wave trough to the west that was bringing drier air aloft and some gradual clearing very late in the day, as seen below.

IMG_7050a.jpg

Late in the day on Tuesday the 7th:  Some clearing was taking place from the north.   This was a rather raw, cloudy day with north breezes.   The photo was taken at a wildlife area north of Valley Falls, about 35 miles north-northwest of Lawrence.

IMG_7052.jpg

A big old buck was being rambunctious.  Well, it is that time of year..

IMG_7080a.jpg

East of Valley Falls, a last gasp light show after sunset as some clearing finally pushed in from the north.

IMG_7081

Wednesday, November 8th:  A sunny, calm and cool day after some early morning clouds.  Upon setting foot the at the Baker Wetlands parking lot in the afternoon, a red tailed hawk immediately swooped in.  I think he was actually interested in Norman, the Dog, before he then noticed me, too.  The red-tail then quickly changed course, alighting on the immediately adjacent light pole.

IMG_7082

The young red tail hawk hung around surveying the scene for a minute.  Deciding there was not much to see after all, he then flew over to a nearby tree top.  This appears to be the same resident juvenile I have photographed previously in the same tree by the interpretive display board near the visitor center.   Rather scraggly-looking before, he is now a handsome fellow.

IMG_7086

The coots and ducks seemed to be enjoying the sunny, cool and calm conditions..

IMG_7102

And the light winds brought good stalking conditions for the herons..

IMG_7114a

Shortly after sunset some Canada Geese approached a watery landing site from which to reach their overnight roosts.

$$

Strong Jet Stream Brings Changeable Weather in October

DSCN7635a.jpg

The sunset as seen from the Clinton Lake Dam on Friday, October 13th.

October is the second of the three transition months of fall, with an 11-degree drop in average temperature during the course of the month.

October also often has some of the most pleasant weather conditions of the entire year,  with sustained mild and dry conditions quite common.  Yet, the month can also be a volatile, as still-available subtropical air from the south brings moisture and energy to any passing weather systems moving in on the strengthening autumn jet stream.

This October, we had both scenarios.

The month started warm and dry.  The warmest temperature of the month occurred on the 2nd with a high of 86.  The next day, October 3rdaveraged 15 degrees above normal with a high of 85 and low 66.  This was the warmest day overall and had the greatest daily deviation above normal, as well.

Temperatures fell to near normal from the 4th to the 7th.  There was also some 1.25 inches of rain over a 72-hour period by the morning of the 7th, thus assuring that October would not be a totally dry month.

The first truly autumn-like day was Tuesday, the 10th, a cloudy day with temperatures hovering in the mid to upper 40s.  There was also a notable shot of brief heavy rain in the early afternoon that brought two tenths of an inch in little more than a half hour.

Next came a strong warming trend with highs ranging from 65 on the 11th to 84 on the 13th.  These warmer and increasingly humid days lead up to the notable ‘wet microburst’ storm of Saturday, October 14th.

Speaking of which, some new information has come to light on this damaging storm event (described in detail in my previous post).  In short, winds at the airport were recorded at 37 MPH initially, building to 72 MPH four minutes later at 4:27 PM.  This coincided with a rainfall rate of over 4 inches per hour from 4:22 to 4:26 PM (0.27 inches in four minutes).  The automated observations from the airport were not transmitted during the high wind portion of the event due to a lightning-caused commercial power outage.  However, the data was recorded internally on backup battery power for a half hour, thus capturing the event at the airport.

The 4 PM storms dropped from three quarters of an inch to around an inch of precipitation within about 45 minutes across town.  During the course of the entire day, an average 1.13 inches of rain across town with an estimated 1.28 inches at the airport.

A cool day on Sunday, October 15th, was followed by a string of fine, mild days from the 16th to the 21st.  The 18th to the 21st averaged 7 to 10 degrees above normal.  An 80-degree high temperature occurred on the 19th, the last of six days reaching the 80s.  I think we can probably say good-bye to the 80s until next spring, at this point.

Late in the afternoon of Saturday, October 21st, another line of strong thunderstorms hit the area, nearly one week to the hour following the microburst event of the previous Saturday.  These storms intensified as they moved in from the west.  At the same time, the entire system slowed down as the upper system started to split off to the south.    When all was said and done, an average 2.41 inches had fallen across Lawrence with 2.32 inches recorded at the airport, making this the most significant rain event of the month.  This was followed by another fine, pleasant day on Sunday, the 22nd.

The first in a series of dry, windy cold fronts pushed in from the north on Monday, the 23rd.  Cold air continued to rush in behind this front under clear skies on Tuesday, the 24th.  Solar heating at the surface combined with a strong push of cold air on a powerful jet stream aloft brought very gusty north winds throughout the day.  These winds were strong and gusty enough to knock down good-sized tree branches around town, along with lots small branches, twigs and leaves.  Winds at the airport topped out a 44 MPH.

The last few days of lower 70s occurred on the 25th and 26th before two additional dry cold fronts swept in from the north.  Northwest winds at the airport gusted to 45 MPH on the 26th, 40 MPH on the 27th and 38 MPH on the 30th.

Low temperatures dropped to 23 degrees on the 28th and 29th at the airport, though most of town, away from the low-lying floodplain at least, was probably closer to 28 degrees, which is what I registered at my residence.

October was not done with us yet, however, as the trick-or-treaters had a trick pulled on them this year.  October 31st reached a high of only 38 under cloudy skies after a morning low of 21.  This averaged out to a deviation for the date of 21 degrees below normal – enough to bring the average for the month down by two thirds of a degree!  A few snowflakes fell around town in the afternoon.  Some areas in the region, such as Topeka, received a few tenths of an inch of snowfall on the grass and leaves.  At least we missed out on that fun.

October as a whole averaged near 70 for a high and 45 for a low.  That was 1.3 degrees above normal for the month overall.  Precipitation-wise, our seven volunteer weather observers across the city averaged out to exactly 5 inches, considerably above the normal of 2.88 inches.

For the year, the city average precipitation average stands at 44.06 inches.  Normal through October 31st is 34.90 inches.

November brings a 14 degree drop in average temperature – the greatest of the three months of autumn.  However, the month usually sees some mild and pleasant days.  So, enjoy the last month of fall while it lasts, leaves and all..!

$$

 

 

New Data Available on the October 14th Microburst Storm

It turns out that there was additional data from the Lawrence Airport on the damaging ‘wet microburst’ event of October 14th.   After a lightning caused power outage at the airport caused the automated weather observing equipment at the Lawrence Airport to stop transmitting data at about 4:14 PM, the equipment kept on observing internally for about a half hour on backup battery power. The last good observation was stored internally at 4:42 PM.  This means that the ‘wet microburst’ event was, in fact, captured from the vantage point of the Lawrence Airport!

Thanks to the staff at NWS in Topeka for providing me with these un-transmitted aviation weather observations that were stored internally during this widespread damaging wind event across northeast Lawrence.

Long story short (more or less), the automated equipment at the Lawrence Airport recorded a first peak gust of 32 knots (37 MPH) from 190 degrees at 4:23 PM.  A second peak gust of 62 knots (72 MPH) from 160 degrees occurred 4 minutes later at 4:27 PM.  According to a note from the NWS, the maximum sustained wind (that is, the greatest average wind speed over a two-minute period) was 39 MPH from 190 degrees recorded at 4:28 PM, one minute after the maximum peak gust.  However, the two peak gusts are of greatest interest to us in analyzing the event, as they indicate the beginning time and magnitude (4:23 PM – 37 MPH) and peak wind time and magnitude (4:27 PM – 72 MPH) of the event at the airport.

The southerly direction of the maximum winds reflects that the airport was not in the direct path of the microburst, but rather, more toward the north side of it.  The winds closer to the center of the microburst would have been out of the southwest, or from around 240 degrees, spreading outward in other directions around the edges.  This means that the winds were likely stronger closer to the core, or central path of the microburst, than what was recorded at the airport.  This is because the core winds of the microburst are added to the prevailing wind direction as well as the speed and direction of travel of the parent storm, which were both from southwest to northeast.

In addition, more precipitation was recorded.  From 4:22 PM to 4:26 PM, concurrent with the two peak wind readings, 0.27 inches was recorded.  This may not sound like much but over 4 minutes this is a rainfall rate of 4.05 inches per hour.  How accurate the measurements are with these rain rates combined with this kind of wind are anyone’s guess, but this kind extreme rate of rainfall concurrent with the strongest winds adds further credence to the notion of a ‘wet microburst’ type of event.

For the storm, 0.99 inches was recorded up to 4:42 PM, which radar imagery indicates was the vast majority of it.  For the day, a total of 1.03 inches was recorded at the airport when some light early morning showers are taken into account.  Additional light to moderate rain showers of another quarter of an inch fell later in the evening during the period the automated equipment was totally out.  So a reasonable estimate of the total rainfall for the day up at the airport is 1.28 inches, 1.03 inches of which was actually recorded.

That is the crux of it.  For a more detailed analysis of this unusual event, we must interpret in a blow by blow manner all the un-transmitted observations now available in conjunction with the earlier transmitted observations.  So, for the other diehards out there, lets get started:

KLWC 142052Z AUTO 35005KT 9SM -TSRA FEW055 FEW075 OVC100 24/22 A2976 RMK AO2 LTG DSNT ALQDS RAB31 TSB48 SLP073 P0001 60002

The above observation is the regularly scheduled hourly that was transmitted normally at 3:52 PM.   There is thunder at the airport, which began at 3:48 PM, and there is light rain.  Winds are light out of the north (350/05KT).


KLWC 142104Z AUTO 30014KT 1 3/4SM +TSRA BR FEW036 BKN075 OVC095 23/23 A2978 RMK AO2 VIS 3/4V5 LTG DSNT ALQDS P0011

At 4:04 PM, a special is generated for visibility criteria (down to 1 3/4 mile) in heavy rain and thunder.  Winds are now WNW and have increased (300/14 KT).  0.11 inches has fallen in the the 12 minutes since 3:52 PM (a rainfall rate of 0.55 inches per hour).


KLWC 142113Z AUTO 28012G24KT 1/2SM +TSRA FG BKN020 BKN055 OVC095 22/21 A2979 RMK AO2 WSHFT 2056 LTG DSNT NE AND SW AND W P0049

The above observation skips two special observations ahead to the last observation actually transmitted. Now the visibility is 1/2 mile in heavy rain and thunder.  Winds have picked up out of the west (280/12G24 KT) or gusting to 28 MPH.  This is pretty standard for local thunderstorms.  Rain is very heavy with 0.49 inches since the hourly (a rate of 2.53 inches per hour over the previous 9 minutes and 1.40 inches per hour over the 21 minutes since the hourly).

20171014_211516_bref1_gray.png

Radar image at 4:15 PM.  The southward extending appendage over Lawrence (dark red blob) just west of the ‘+’ for the location of ‘LWC’) is the apparent incipient microburst.

20171014_212032_bref1_gray.png

4:20 PM Radar image.  The microburst is a subtle, yet potent feature and is right over Iowa Street at this time.

KLWC 142122Z AUTO 24012G16KT 1SM TSRA BR SCT018 BKN042 OVC065 22/21 A2980 RMK A02 WSHFT 2056 LTG DSNT NE AND SW AND W P0057

Above we see the first stored but un-transmitted observation.  Winds are southwest now but not real strong (240/12g16 KT).  The special is for visibility criteria, now up to a mile due to a bit of a lull in the rainfall, just ahead of the big event.

20171014_212550_bref1_gray.png

4:26 PM:  Here we see the microburst moving eastward mostly just south of the airport (+) just west of ‘LWC’.   This kind of verifies the idea that the airport caught the north portion of the microburst and was not in the core area of it, which was a bit more to the south across north Lawrence.

KLWC 142126Z AUTO 24012G16KT 1/2SM RA  FG BKN016 BKN042 OVC065 22/20 A2976 RMK A02 PK WND 19032/2123  WSHFT 2056 TSE24 PRESFR P0084

In the above 4:26 PM observation, we see the first indication of the microburst.  The rain is heavier again with the visibility down to a half mile.  While the average wind over the preceding 10 minutes is still 240/12G16 KT there is a peak wind remark, showing 190 at 32 KT at 4:23 PM, or south at 32 knots at 4:23 PM.   This could be considered the start of the microburst event at the airport.  Rainfall is now up to 0.84 inches since the hourly.  This represents a rate of 4.05 inches per hour in the 4 minutes since the last special and 2.1 inches per hour in the 24 minutes since the hourly.   This is wet microburst stuff.

20171014_213309_bref1_gray.png

4:33 PM:  Same time as the un-transmitted observation below.  The airport already appears just out of the microburst zone on radar.

KLWC 142133Z AUTO 24017G45KT 1/4SM RA FG BKN016 BKN044 OVC080 23/21 A2977 RMK A02 PK WND 16062/2127  WSHFT 2056 TSE24 P0092

Here we have recorded the maximum wind of the event in the peak wind remark.  The observation shows a peak wind of 160 degrees at 62 knots (72 MPH) at 4:27 PM.  The south wind from the microburst has probably been rising steadily over the previous 4 minutes since the 32 knot peak wind of the previous observation at 4:23 PM.  Visibility is down to 1/4 mile, indicating the very heavy rain and whatever debris might be blowing in the wind.  Rainfall is now 0.92 since the hourly.  This is a rate of 1.91 inches per hour over the previous 11 minutes and 1.34 inches per hour in the 41 minutes since the hourly.  So the rain rates, while very high, are lower than the last observation.


KLWC 142136Z AUTO 24019G45KT 3/4SM -RA BR BKN019 BKN044 OVC085 22/21 A2978 RMK A02 PK WND 16062/2127  WSHFT 2056 VIS M1/4V4 TSE24 P0093

Three minutes later another special is generated for visibility criteria.  The visibility shows at  3/4 mile while the rainfall shows as light, verified by only another 0.01 inches in the last 3 minutes.  This I cannot readily explain.  One possible reason is the rain bucket is not registering all the rain.  Another possible explanation is there is actually a strong lull in the rain right behind the microburst, which is equally plausible.  There is a also variable visibility remark, showing the prevailing visibility ranging from less than 1/4 mile to 4 miles.  Visibility in an observation goes back goes back over the previous 10 minutes, so the less than 1/4 mile visibility is probably during the height of the microburst wind and rain event between about 4:23 and 4:28 PM.

20171014_213840_bref1_gray.png

4:38 PM – Two minutes after the previous un-transmitted observation above.

KLWC 142142Z AUTO 22020G32KT 2SM RA BR SCT029 BKN044 OVC085 22/21 A2977 RMK A02 PK WND 16062/2127  WSHFT 2056 VIS M1/4V4 TSE24 P0097

The above is the last good observation before the battery went dead.  Visibility is up to an average 2 miles in rain with the same variable visibility remark as the previous  observation.  Winds are pretty strong, averaging out of the southwest (220 at 20 gusting 32 knots), which is the ambient or prevailing direction of the winds.  Rainfall is up to 0.97 inches.  This is a rate of 1.20 inches per hour over the previous 20 minutes and 1.16 inches per hour in the 50 minutes since the hourly.

20171014_214417_bref1_gray.png

4:44 PM – Two minutes after the last un-transmitted observation above.

20171014_214940_bref1_gray.png

4:49 PM.  The microburst seems to have created a void behind it which is now moving across Lawrence.

Another interesting observation of the event came from one of our CoCoRaHS rainfall observers located just west of Trail Road and Lawrence Avenue in north-central Lawrence:

“Thunderstorms late Saturday afternoon; severe with very strong winds (microburst?) for a few minutes beginning at 4:18 PM. Much tree damage in my neighborhood, but appeared to be less just to the west near Kasold Drive and south of 6th Street on Lawrence Avenue. Suspect measured total precipitation is less than accurate as rain was “falling” sideways during the strong winds.”

Storm reports of considerable damage for north Lawrence were reported to be at about 4:20 PM (generally north of 9th Street and east of Iowa Street).

The microburst is first recorded at the airport at 4:23 PM with a south wind gusting to 37 mph, peaking 4 minutes later at 4:27 PM at 72 MPH.  The south wind direction at the airport, however, indicates a glancing blow.  Nevertheless, the strong winds are concurrent with a measured rainfall rate of 4.05 inches per hour in the 4 minutes between specials generated at 4:22 and 4:26 PM (0.27 inches in 4 minutes).

The above paints a fairly clear picture of a wet microburst event that started near Lawrence Avenue and Trail Road at 4:18 PM (near Dillon’s Grocery at 3000 W 6th St), moved into northeast Lawrence at 4:20 PM (mainly north of 9th Street and east of Iowa Street) and then registered at the Lawrence Airport at 4:23 PM with a 37 MPH peak gust, then maxing out at 4:27 PM  with a another peak gust of 72 MPH.  A brief but very intense deluge accompanied the strong winds.

Due to the apparent glancing blow at the airport (indicated by the southerly wind direction) an even stronger event was likely unfolding within the wide zone of extensive damage across north Lawrence.

$$