Back to Summer / Month and Year to date Lawrence Precipitation

September 19th:  Tuesday felt distinctly summer-like with a high temperature of 90 and the dew point hovering around 70 on breezy south winds.  This was quite a contrast from Monday’s maximum of 78 following the heavy late morning thundershowers.

Speaking of Monday’s late morning rainfall, the Lawrence 7-station average precipitation was 0.61 inches in the 24-hour period ending at 7 AM Tuesday.  The airport picked up another hundredth of an inch early Tuesday morning from some early morning showers that brushed north Lawrence but mostly missed to our east, bringing the airport 24-hour total to 0.37 inches.   While the airport rainfall figure for Monday’s event is only about 61 percent of the Lawrence city average, in this case the difference appears to reflect actual local variability.

Southwest Lawrence again picked up the most precipitation in our 7-site Lawrence network with both stations in that part of town measuring 0.80 inches.  The three northwest Lawrence rainfall sites averaged 0.44 inches.  The two stations in east-central Lawrence averaged out to 0.675 inches (one was 0.67 and the other 0.68 inches).

An updated 7-station Lawrence average from the major event late Saturday night and early Sunday morning came in at 2.59 inches after a late report was averaged in from one of our seven Lawrence measuring sites. (People are not always home, after all, even within the CoCoRaHS Network).   The 2.59-inch Lawrence 7-station average came in close to the 2.63 inches measured at the airport.

For the month, the total at the Lawrence Airport is now 3.00 inches, compared to a normal month-to-date of 2.74 inches.  The Lawrence 7-station average total for the month is 3.22 inches.

For the year to date, the Lawrence 7-station precipitation average is 38.69 inches, compared to a normal year to date of 30.60 inches.  Ignoring several equipment malfunctions, the NWS reports the Lawrence year to date precipitation as 30.14 inches.


Visual Satellite at 4:15 PM today.  Clear skies and warm, breezy south winds prevailed today.  A cold upper trough of low pressure brought fall-like weather in the northwest part of the country.  Tropical Storm Jose, demoted from category one hurricane status, continues its slow northward meander off the east coast.  Strong storms can be seen over eastern North Dakota this afternoon.


This evenings jet-stream flow at the 250 MB level shows a screaming-fast jet for this time of year centered from northwest Oregon to southern Wyoming before it diverges northward across the Dakotas.  This area of divergence aloft creates more upward vertical motion in the atmosphere that enhances precipitation processes.


A water vapor image at 7:45 PM shows very dry air aloft extending over eastern Kansas from the southwest with high clouds to our west; the strong jet stream pushing into Oregon; cold air instability showers over the northern Rockies from northeast Washington across the western half of Montana and the strong thunderstorm development on diverging jet stream winds extending across the eastern Dakotas into northwest Minnesota.


The surface chart at 8 PM shows a string of lows associated with a slow-moving cold front and the cold upper trough over the northern Rockies.  A strong pressure gradient over our area is bringing us the warm and humid south winds that continue late tonight.  In fact, the temperature outside my residence at 10:30 PM is a downright tropical 79 degrees with a dew point of 71, a reminder that, astronomically speaking at least, we are still in the summer season.


At 10:30 PM, CDT, an intense and well-formed Hurricane Maria looks to make a direct hit on Puerto Rico tomorrow.






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