Area Forecast Discussion
Issued by NWS St. Louis, MO
Issued by NWS St. Louis, MO
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399 FXUS63 KLSX 161700 AFDLSX Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 1200 PM CDT Mon Sep 16 2024 .KEY MESSAGES... - It`ll be another warm day today with isolated showers and thunderstorms this afternoon. This is the last meaningful opportunity for rain this week. - Dry and warm weather lasts at least through the end of the workweek. && .SHORT TERM... (Through Late Tuesday Afternoon) Issued at 230 AM CDT Mon Sep 16 2024 The upper air pattern across North America is dominated by a broad ridge of high pressure across the central and eastern portions of the continent, along with a deep trough over the West Coast. To the south of the eastern ridge a broad trough axis persists although it is reorganizing. The old core of this trough continues to spin across Arkansas, but further to the east a tropical low has developed and will soon become the dominant low. The National Hurricane Center expects to upgrade this to a Tropical Storm soon, before it makes landfall in the Carolinas later today. At the surface, high pressure centered offshore of New England extends its influence westward into the Great Lakes maintaining an easterly flow across our region. This flow has brought progressively drier air into our area over the past few days and this trend continues again today. This drier air should limit the coverage of showers and thunderstorms this afternoon relative to the past few days. In fact, this should be the last day that we see any chance of rain as the remnant upper low to our south gets fully absorbed by the new developing low to its east. With drier air moving in from the east, we`ll see a subtle drop in low temperatures tonight and Tuesday night relative to the past few nights as the dry air allows for a lower floor for temperatures in good cooling conditions. Daytime highs remain consistently in the mid to upper 80s with considerably less cloud cover once the influence of this upper low departs. Kimble && .LONG TERM... (Tuesday Night through Sunday) Issued at 230 AM CDT Mon Sep 16 2024 The tropical system moving into the southeast US will move into the Appalachians and stall, spinning there for several days. Our area will be in between this stalled low to our east and the persistent trough in the West, leaving us in relative ridging. That spells dry and warm conditions through at least the end of the week with highs each day reaching well into the 80s or even low 90s. We do start to see some low thunderstorm chances (20 to 40 percent) creep into western parts of our forecast area this weekend. This is a result of multiple embedded waves ejecting out of the Western US trough this week gradually inching closer to our area. Still, though, the best forcing associated with these waves stays to our west and north as ridging developing over the Southern Plains deflects this energy around us. For this reason we expect the dry trend to continue for most of the region which will only allow the developing drought to persist and intensify. Kimble && .AVIATION... (For the 18z TAFs through 18z Tuesday Afternoon) Issued at 1154 AM CDT Mon Sep 16 2024 VFR flight conditions are expected through much of the TAF period at all local terminals. Isolated showers and possibly a thunderstorm are expected this afternoon mainly south of the local terminals. If any of the local terminals were to be impacted by these, KCOU and KJEF have the best chances; though, the chances are still quite low. Another round of fog is expected tonight, though impacts to terminals are uncertain currently, so reductions in visibility have been left of the TAFs for now. Elmore && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX