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.
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.
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.
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.
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.
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.
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..
Here is the incoming trough at 700 MB (about 10,000 ft).
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.
Saturday morning, November 18th, the upper trough moves across with the jet max sinking southward.
Here is the deepening700 MB trough with some moisture and colder air moving in on strong north winds.
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.
Looking east at Deer Creek Wildlife Area at 4:30 PM, we see some lingering, ragged, dissipating cumulous as northwest winds gradually decrease.
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).
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.
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.
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.
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.
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.
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.
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.
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.