Area Forecast Discussion
Issued by NWS Paducah, KY
Issued by NWS Paducah, KY
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713 FXUS63 KPAH 192327 AAA AFDPAH Area Forecast Discussion...UPDATED National Weather Service Paducah KY 627 PM CDT Wed Jun 19 2024 .KEY MESSAGES... - More hot and humid conditions return late this week and continue through the weekend. High temperatures will rise into the mid to upper 90s with heat index values near 100 degrees. - A cold front will bring the next best chance of a few showers and thunderstorms Sunday afternoon into Sunday evening, followed by brief relief from the heat and humidity on Monday. - The heat and humidity quickly rebound the middle of next week with a more unsettled weather pattern that may lead to an elevated hydro risk. && .DISCUSSION... Issued at 138 PM CDT Wed Jun 19 2024 As of 18z this afternoon, a 597 dm ridge was located over the mid atlantic region and will begin to retrograde west into the Ohio Valley through the end of the week. Weak synoptic flow aloft will allow for robust diurnal heating with maxTs trending hotter into the mid 90s and minTs in the low to mid 70s by the weekend as southwesterly flow advects in higher dewpoints. This will translate to heat index values near or above 100 degrees Friday through Sunday across portions of the FA. Although we are short of the PAH criteria of 4 consecutive days for a heat advisory, portions of SEMO may get close to the 105 degree threshold on Sunday. This will certainly be a weekend you will want to stay well hydrated if outdoors for an extend period of time! The NBM keeps the PoPs silent until Sunday as tranquil weather is progged. One caveat to the forecast is Friday afternoon as the GFS/GEFS have isolated convection developing along a theta-e gradient in the afternoon across portions of southwest Indiana and western Kentucky. Meanwhile, the EPS/GEPS are completely dry! Not really seeing much of a forcing mechanism to support this with a big ridge aloft, but it does appear we will exceed the convT of upper 80s in the afternoon. Given low confidence, have maintained NBMs silent PoPs for now. Should anything develop, a stray gusty thunder shower would not be out of the question. Model guidance is also similar with Saturday, but more east. By Sunday, a 500 mb trough will eject out of Canada and dig across the Great Lakes region leading to height falls over the FA. This will put the breaks on additional heat building in as a cold front will eventually bring our next best risk for some scattered showers and thunderstorms Sunday afternoon into Sunday evening. The GEFS again is wetter compared to the EPS/GEPS with QPF, but the overall model ensemble consensus does support a 40-60% probability of seeing at least mensurable QPF below a tenth of an inch. One thing worth noting is the GFS is a bit more robust with a 700 mb shortwave that could enhance forcing a bit with model soundings supporting 1000- 1500 J/kg of MLCAPE and about 25-30 kts of effective bulk shear. The CSU-MLP guidance does support a marginal risk for stronger storms, but confidence is very low at this time. Should the parameters come together, isolated strong gusty winds would be the main concern with DCAPE exceeding 1000 J/kg. Right now, NBMs 20-30% PoPs that are progged of actually seeing a storm seem reasonable given uncertainty in how widespread convection will be. The aformentioned cold front will bring some brief relief on Monday with less humid conditions as temps and especially dewpoints will be a few degrees lower. By the middle of the week, the heat and humidity will quickly rebound as the ridge gradually builds back across the southern Plains. Multiple impulses that round the ridge could bring more storm chances. The NBM again shows heat index values pushing well into the triple digits, but this may be a bit overdone given the potential for convection with the mean a few degrees lower. In fact, the NAEFS/ECMWF ESAT`s both show mean specific humidity exceeding the 90th percentile, supporting the potential of an elevated hydro risk. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 627 PM CDT Wed Jun 19 2024 VFR conditions are forecast through tonight with relatively light winds. Middle clouds at 4000 to 6000 ft should be the only sky impediment. Moisture and thermal profiles currently appear unfavorable for fog overnight despite light winds. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...Air Quality Alert from midnight CDT /1 AM EDT/ tonight to midnight CDT /1 AM EDT/ Thursday night for INZ081-082- 085>088. KY...None. && $$ DISCUSSION...DW AVIATION...JGG