Area Forecast Discussion
Issued by NWS Paducah, KY
Issued by NWS Paducah, KY
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342 FXUS63 KPAH 211743 AFDPAH Area Forecast Discussion National Weather Service Paducah KY 1243 PM CDT Sat Sep 21 2024 .KEY MESSAGES... - Another very warm and humid day is expected to start off the weekend with highs around 90 again. The heat index may reach 100 degrees in a few locations. There is a small chance of showers and storms, especially across southeast Missouri. - A cold front will slowly push through the region Sunday into Monday, bringing periods of showers and storms. The risk for severe storms is marginal Monday, with isolated damaging winds and hail being the main hazards of concern during peak heating. Total rainfall between 0.5 to 2.0 inches is possible, with locally 3.0 inches along the I-64 corridor. - Cooler and less humid conditions arrive behind the cold front for the rest of the week with highs only ranging from the upper 70s to lower 80s. Rain chances may linger on Tuesday, with additional low rain chances possible towards the end of the week. && .UPDATE... Issued at 1243 PM CDT Sat Sep 21 2024 Updated aviation discussion for 18Z TAFs. && .DISCUSSION... Issued at 323 AM CDT Sat Sep 21 2024 Upper level ridging will peak this morning across the FA as another very warm and humid day is on track with high temps once again rising to around 90 degrees. Dewpoints in the 70s will cause the heat index to reach 100 degrees in a few locations. More isolated to scattered showers and storms are possible today, especially across portions of southeast Missouri, far southern Illinois, and far western Kentucky due to subtle 500 mb energy. However, confidence in the spatial coverage and timing is low as the 0z CAMs differ quite a bit with how they handle a decaying complex of storms upstream and additional diurnal development along residual outflow boundaries. Cannot entirely rule out a strong storm or two with gusty winds given pockets of DCAPE between 1000-1200 J/kg, effective bulk shear of 25 kts, and steep sfc-3km lapse rates around 7.0-7.5 C/km. Despite the uncertainty, most of the day is still likely to be dry where storms do occur. The second half of the weekend will turn even more unsettled as additional 500 mb impulses upstream provide more forcing ahead of a shortwave associated with a closed low that will move across KS/NE. NBM PoPs turn likely to categorical along the I-64 corridor Sunday morning with the first wave of showers and storms, followed by the potential for another round Sunday night as a potent cold front slowly sags southeast. Similar to Saturday, a strong storm or two cannot be ruled out again. Due to locations further south remaining mostly dry with less cloud cover, a sharp gradient in the temps will setup with highs only in the low to mid 80s along the I-64 corridor. Meanwhile, all of southeast Missouri and western Kentucky are progged to reach the upper 80s to near 90. This may very well be the last day most locations if not all in the FA reach 90 degrees as we transition into the fall season. Rain chances peak Monday afternoon into Monday night to start off the new week when widespread showers and storms will be likely across most of the FA due to more robust forcing associated with a 500 mb shortwave and sfc convergence. SPC does have a marginal risk of severe weather in their D3 convective outlook across much of the CWA with isolated damaging winds and hail being the main hazards of concern during peak differential heating. The parameters are certainly supportive with MLCAPE between 1000-2000 J/kg, sfc-6km shear between 30-40 kts, and sfc-3km lapse rates between 7.0-9.0 C/km. Any severe risk likely wanes after sunset, but additional storms will still be possible through the overnight. As for the flooding potential, the risk for excessive rainfall remains very marginal due to the recent dry soil conditions. However, QPF has trended even higher quite a bit with among all the model ensembles. Total rainfall through Monday night between 1.0 to 2.0 inches, locally 3.0 inches is possible across southern Illinois, and southwest Indiana, while 0.5 to 1.5 inches is now possible in southeast Missouri and western Kentucky. Once again, there will be a large diurnal range in the temps from northwest to southeast, with highs in the upper 70s to upper 80s. The rest of the week will feature much cooler conditions and lower humidity as 500 mb troughing will be in control over the central CONUS. Rain chances may linger on Tuesday, but it is possible the middle of the week turns drier before low rain chances return at the end of the week. This is contingent on when a 500 mb cutoff low develops as models differ quite a bit with northern stream energy that ejects out of Canada. The placement will have implications on if we see any moisture from the potential tropical system next weekend, and is why forecast confidence remains very low. The synoptic setup is certainly quite a wild one to put it in simple terms as some of the model guidance shows the tropical disturbance phasing with the 500 mb cutoff low. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1243 PM CDT Sat Sep 21 2024 VFR conditions are forecast to prevail through tonight and Sunday. The potential for isolated/scattered showers and thunderstorms is greatest this afternoon near KCGI/KPAH, and Sunday morning from KMVN to KEVV. However, much of the overnight period should be dry. Some patchy fog cannot be ruled out late tonight, in particular at KCGI. Winds will be light from the south/southwest. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ UPDATE...RJP DISCUSSION...DW AVIATION...RJP