Area Forecast Discussion
Issued by NWS Paducah, KY
Issued by NWS Paducah, KY
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826 FXUS63 KPAH 041135 AFDPAH Area Forecast Discussion National Weather Service Paducah KY 635 AM CDT Thu Jul 4 2024 .KEY MESSAGES... - Multiple rounds of thunderstorms are expected through late tonight. A few storms may be strong to severe with damaging winds the main threat. - The thunderstorms will produce heavy rain, and areas of flash flooding are possible across parts of Southeast Missouri, Southern Illinois, far Northwest Kentucky, and Southwest Indiana. The Flood Watch has been expanded, and remains in effect through late tonight. - Sultry heat and humidity will continue through early tonight for southern portions of the area, and a Heat Advisory is in effect until 9 PM CDT. - Drying out with less hot and humid conditions this weekend. The next chance of thunderstorms arrives early next week. && .UPDATE... Issued at 633 AM CDT Thu Jul 4 2024 Updated the aviation section for the 12Z TAF issuance. Early morning convection is now along and north of the I-64 corridor. PoPs have been reduced through the daytime hours as most rainfall will remain north of the forecast area. This is likely to also result in warmer temperatures and higher heat index values, which will need to be monitored for possible expansion of the heat advisory should clearing remain for an extended duration. && .DISCUSSION... Issued at 414 AM CDT Thu Jul 4 2024 A few showers and thunderstorms are moving northeastward in Southwest Illinois and in the far northeast corner of the Quad State. Fog developed at multiple sites along the I-64 corridor, but any showers and storms should clear it out, at least temporarily, with some visibility reductions through the early morning possible in areas that dodge early morning rain. Models agree fairly well on the progression of an MCS in eastern Kansas through Missouri into Illinois, with a trend towards the bulk of this system passing north of the Quad State. A boundary moving through should yield at least a few showers and storms this morning, and a strong to severe storm cannot be ruled out. Instability will develop quickly today, but shear is quite weak, leaving damaging winds the primary severe weather hazard. With morning rainfall coming primarily from a north- south oriented line moving eastward rather than training storms, the flooding potential this morning is somewhat reduced though additional storms remain later. With the storm track shifting northward, partial clearing becomes more likely with temperatures in southern portions of the Quad State reaching the lower 90s. With dew points in the mid to upper 70s with localized 80 values, heat index values above 105 are fairly likely. With the upward adjustment in heat index values in the forecast, and especially considering that today is an outdoor activity focused holiday, a Heat Advisory has been issued for most of Southeast Missouri, southern portions of Western Kentucky, and part of far Southern Illinois through 9 PM this evening. Heavy rain produced flooding issues in Southeast Missouri and Southwest Indiana Wednesday evening. Soils are more primed for additional heavy rain. Precipitable water values remain around 2 inches, enabling heavy rain rates. A few models produce afternoon thunderstorms as, with high instability, any residual boundary could easily fire additional storms. On average, models are drier for the early evening hours, but unfortunately, storms cannot be ruled out. An MCS develops in Missouri during the evening, then progresses eastward as the cold front shifts towards the Quad State. Models suggest this MCS will be trending weaker in the Quad State, limiting severe weather potential (a slight risk covers much of Southeast Missouri, while the rest of the Quad State is in a marginal risk), but heavy rain remains a concern. Due to the multiple chances of heavy rain, and taking into account locations such as the Ozarks and Southwest Indiana which had flooding issues yesterday evening, the Flood Watch has been expanded southwestward and eastward to cover those areas, as soils are more susceptible to additional rainfall. A cold frontal passage early Friday brings an end to precipitation. As high pressure moves in, cooler and less humid conditions make for a pleasant weekend with highs in the mid to upper 80s and lows in the 60s. The forecast becomes complicated next week as a trough deepens in the Plains and a ridge to the southeast pushes off to the east. A boundary with the trough brings shower and storm chances late Monday into Tuesday. The shifting of the ridge may enable Hurricane Beryl to turn more northward towards Texas. Uncertainty beyond that is fairly high due to model spread on how far southward the trough digs, but there is potential for moisture from the storm to be drawn northward and contribute to rain chances the middle of next week. The forecast trends towards some warming and moistening of air next week but to what extent will need clarifying, especially with regards to contributions from Beryl. && .AVIATION /12Z TAFS THROUGH 12Z FRIDAY/... Issued at 633 AM CDT Thu Jul 4 2024 Morning storms are now limited to the far northern areas of the Quad State and further north, making predominantly dry conditions through the day for most TAF sites. There is some potential for afternoon showers or storms to develop, and storms should move through overnight ahead of a frontal passage. Pockets of LIFR-IFR cigs/vsbys this morning in the north should improve within an hour or two with MVFR to VFR cigs. Light winds will increase out of the southwest to 5-10 kts today, then become light again after sunset. Gusty winds will be possible with thunderstorms. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...Flood Watch through late tonight for ILZ075>078-080>087. Heat Advisory from noon today to 9 PM CDT this evening for ILZ088-089-092>094. MO...Flood Watch through late tonight for MOZ076-086-087-100- 107>109. Heat Advisory from noon today to 9 PM CDT this evening for MOZ086-087-100-107>112-114. IN...Flood Watch through late tonight for INZ081-082-085>088. KY...Flood Watch through late tonight for KYZ014-018-019. Heat Advisory from noon today to 9 PM CDT this evening for KYZ001>006-008-009-012-017-022. && $$ UPDATE...ATL DISCUSSION...ATL AVIATION...ATL