Current Conditions at Sanborn Field

 

Monday Night: Increasing Clouds. Low: 43

Tuesday: Rainy, clearing late. Gusty Winds. High: 53

Tuesday Night:  Clouds thinning through the night. Low: 41

Wednesday: Mostly clear. High: 56

Wednesday Night: Clouds increasing late. Low: 32

 

Thanks to IconArchive.com for the icons!

====================================================================

Discussion: A one-two punch is expected this week with two storm systems bringing us impacts. The first of the pair will impact us tomorrow bringing some moderate rainfall in the range of 0.25-0.50" and strong winds with gusts upwards of 50 mph. A second system will swing through towards our Thursday bringing a steep drop in our temperatures with gusty winds, and some isolated showers with a rumble of thunder.

-Russell

 =================================================================

Forecasters: Russell, Shaw

Date Issued: 2/13/2023 05:00PM CST

Technical Discussion:

 

An active pattern persists as we move through our week bringing two storm systems through the Midwest within the next 4 days. Starting with Valentines Day, a low off to our southwest will bring a push of moisture which when paired with the strong low level jet overhead will promote strong winds with gusts in excess of 40mph. A second system is expected to push into the region from the west bringing some more gusty winds and a steep drop in our temperatures. Overall, expect 0.25-0.5" of rainfall over the next 3 days with the majority of that falling tomorrow. For this forecast, a blend of the Euro and GFS due to their better handling of the trough ejection over the southwest.

 

An area of upper level ridging is currently residing over the area allowing from warm, moist air to infiltrate the state ahead of our next storm system. A powerful subtropical jet will gradually shift overhead as a long wave trough dives south over the continental divide. A jet streak situated to our south will place us directly in the left exit region promoting divergence aloft enhancing upwards motion at the surface coinciding with our peak precipitation rates Tuesday midday. As we move through Tuesday, the polar jet continues to dive down with a potent trough across the inter mountain west. Due to the southward extent of the polar jet, we see it couple with the subtropical jet by Tuesday evening, happy Valentines Day! The trough will gradually shift east before parking to our northwest keeping us in the southwest flow steering our next system Wednesday into Thursday. 

Moisture in the mid levels will start to increase this evening before with the column reaching saturation by 15z Tuesday which is when peak rainfall rates are anticipated. The low level jet will intensify through the morning peaking with winds 45-65kts during the peak precipitation. Due to the timing, the rainfall will lead to mixing paired with the tightening pressure gradient will lead to strong winds gusts over 40 mph. The 700 levels will remain saturated through early Wednesday morning, but down at 850 a dry slot will wrap into the low as it begins to occlude to our northwest. The dry air will extend down to our surface which will cut our precipitation totals and allow for a brief dry time before wrap around moisture brings the opportunity for some showers that may contain a rumble of thunder. Moisture will completely exit the area by Wednesday morning leaving us with only some high clouds. Moisture then again begins to increase Wednesday night with increasing mid-level clouds Thursday morning. Thanks to an dry layer at the 700 level Thursday afternoon precipitation looks minimal. 

A weak surface high pressure is currently over head and expected to gradually shift to the east across the Ohio Valley. This will leave us with consistent southerly winds through tonight and into Tuesday keeping our temperatures above average and rather warm despite the ongoing rainfall through most of Tuesday. As the low pressure across the central plains moves northeast, things will quickly dry out and winds will become southwesterly maintaining our warm but dry air into Wednesday as well. Low level dry air Wednesday night into Thursday will further complicate the forecast and maintain low precipitation chances. As the low pressure continues to glide to our south dry air following the system will completely cut off any precipitation chance Thursday midday. A steep drop in temperatures following the storm system will round out our Thursday morning leading to a midnight high and falling temperatures throughout Thursday. Future forecasters should pay close attention to moisture levels of the column as a slight increase could lead to more precipitation the currently foretasted as well as the timing of cold frontal passage which could bust temperature forecasts.