Area Forecast Discussion
Issued by NWS St. Louis, MO
Issued by NWS St. Louis, MO
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668 FXUS63 KLSX 281906 AFDLSX Area Forecast Discussion National Weather Service Saint Louis MO 206 PM CDT Tue May 28 2024 .KEY MESSAGES... - Isolated showers and thunderstorms will move southeast across parts of northeast Missouri and west central and southeast Illinois through early this evening. Gusty winds are possible with the stronger storms. - Dry weather is expected Wednesday and Thursday with near normal temperatures. - The chance of showers and a thunderstorms will return Thursday night through next Tuesday with temperatures climbing above normal. The risk for severe weather for strong to severe weather remains low. && .SHORT TERM... (Through Late Wednesday Night) Issued at 158 PM CDT Tue May 28 2024 Latest water vapor imagery is showing another shortwave trough moving southeast across the Upper Midwest that the RAP brings the southern end of it across the area later this afternoon and early this evening. The weak ascent provided by this shortwave and weak instability (RAP MUCAPES in the 500-1000 J/kg range) support keeping isolated showers and thunderstorms across northeast Missouri and west central and south central Illinois through early this evening. Like yesterday, RAP soundings are showing some inverted V profiles, so couldn`t rule out some gusty winds with some of the stronger storms. These storms will die out after sunset with the loss of daytime heating, and then expect dry weather through tomorrow night as the HREF is showing a upper ridge and a surface high moving in from the Plains. Temperatures will be slightly cooler over the next 24-36 hours as the surface ridge moves through the area causing the winds to veer from northwest to northeast. this will cause weak cold air advection and temperatures too fall slightly below normal. Britt && .LONG TERM... (Thursday through Next Tuesday) Issued at 158 PM CDT Tue May 28 2024 There is reasonable agreement in the global models with a upper ridge moving through the area on Thursday and a shortwave trough moving through the Midwest slightly slower on Saturday compared to yesterday. Thereafter, we will be in quasi-zonal flow going into early next week which the individual models have different timing of subsequent shortwaves. At this point the LREF has the most members (40-50%) showing precipitation chances on Friday night and Saturday and again Monday into Tuesday with a break in between. Severe weather chances during this period looks relative low as the overall CAPE/shear parameter space in the model guidance is not nearly as supportive of the level of severe weather that we have seen in the past week and the CIPS/CSU guidance is not particularly impressive. Temperatures will start out just below normal on Thursday before climbing above normal Sunday through Tuesday as 850mb temperatures increase and low level flow turns more south-southwesterly. Confidence in the warm up is increasing as the NBM IQR is only 4-6 degrees through next Tuesday. Britt && .AVIATION... (For the 18z TAFs through 18z Wednesday Afternoon) Issued at 1219 PM CDT Tue May 28 2024 VFR flight conditions are expected to prevail through the period. An upper level wave is producing some showers across Iowa at this time, and most guidance shows isolated to widely scattered showers and thunderstorms moving into northeast Missouri and west central Illinois after 20Z this afternoon. A few models even bring the convection down into east central Missouri and southwest/south central Illinois before sunset this evening, however the majority keep the precip north of I-70. Due to the low coverage and low probability, have kept the terminals dry for this update. Carney && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX