Area Forecast Discussion
Issued by NWS Paducah, KY
Issued by NWS Paducah, KY
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954 FXUS63 KPAH 281719 AAA AFDPAH Area Forecast Discussion...UPDATED National Weather Service Paducah KY 1219 PM CDT Fri Jun 28 2024 .KEY MESSAGES... - The heat and humidity returns today and Saturday with heat index values near to slightly above 100 degrees. - A front will bring the next chance of showers and storms on Saturday. The greatest risk looks to be Saturday evening into Saturday night when isolated strong to severe storms will be possible. Damaging winds, small hail, torrential downpours, and lightning are the main concern. - Brief relief from the heat and humidity is in store Sunday into Monday before turning uncomfortable again in time for the 4th of July. The pattern also turns unsettled by the middle of the week. && .DISCUSSION... Issued at 142 AM CDT Fri Jun 28 2024 Another period of hot and humid conditions is in store for Friday and Saturday as southerly return flow advects in higher dewpoints in the 70s with ridging aloft over the SE CONUS. The increase in moisture will cause heat index values to peak near to slightly above 100 degrees. As a 500 mb trough digs across the Dakotas, subtle height falls will begin to occur into the weekend. The CAMs show a MCS over central Missouri Friday night decaying across the FA Saturday morning as a shortwave passes by to the north. The FV3 is an outlier with a line of showers and storms moving towards the Mississippi around 12-14z while most other guidance amounts to just a few isolated showers or storms at most. Assuming there is not much in the way of morning convection, both the NAM/GFS support MLCAPE between 2000-3500 J/kg developing by the afternoon and SBCAPE peaking around 4000-5000 J/kg with dewpoints well into the mid 70s. As a cold front sags south ahead of a 500 mb trough that digs across the Great Lakes, an influx of theta-e around 350K sets up along the boundary. Model guidance supports the potential for another MCS developing in central Missouri Saturday evening and moving downstream across portions of the FA. Given DCAPE over 1000 J/kg, steep low-level lapse rates around 7.5 C/km, and effective bulk shear around 25-30 kts, isolated strong to severe storms will be possible with damaging winds, small hail, and lightning being the main hazards of concern with a liner storm mode. The exact timing is still a bit uncertain, but would expect the risk to gradually wane overnight with the loss of diurnal heating given a typical high CAPE and low shear summertime setup. The front may be slow to clear out Saturday night into Sunday morning as the flow between 925-700 mb becomes parallel to the aformentioned front with deep layer moisture still present. The NAEFS ESATs shows PWATs above the 95th percentile between 2.00-2.25" supporting the potential for torrential downpours with convection. In fact, model soundings show warm rain processes will be quite sufficient with the warm cloud layer reaching 15 kft. Despite the soupy airmass, do think convection will move through fast enough to limit any localized flooding issues to typical poor drainage in low- lying areas. QPF looks to only be between 0.50 to 1.00 inches where storms occur as it is also possible some locations see little rainfall. Behind the front, a 1027 mb sfc high pressure builds into the Ohio Valley Sunday afternoon into Sunday night providing relief from the heat and humidity. North-northeast winds associated with anticyclonic flow advect in lower dewpoints in the 50s/60s as Monday looks to be another pleasant day similar to yesterday. In fact, maxTs struggle to reach 90 on Sunday and are progged by the NBM to only reach the low to mid 80s on Monday. Given radiational cooling Sunday night, some locations could even see minTs fall into the upper 50s! Moisture along with the heat looks to return in time for the 4th of July as a ridge builds over the SE CONUS. The pattern also looks to be fairly unsettled and potentially stormy through the second half of next week as multiple shortwaves upstream eject south towards the FA. Heat index values once again rise into the triple digits by Wednesday. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1219 PM CDT Fri Jun 28 2024 VFR conditions with moderate south winds are forecast for the rest of the day. Overnight tonight fog may become an issue, particularly CGI-MDH-MVN. Convection may also be a factor in the late overnight and early morning but the trend, for now, is for it to hold off until after the current TAF period. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ DISCUSSION...DW AVIATION...JGG