Area Forecast Discussion
Issued by NWS Paducah, KY
Issued by NWS Paducah, KY
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796 FXUS63 KPAH 160835 AFDPAH Area Forecast Discussion National Weather Service Paducah KY 335 AM CDT Tue Jul 16 2024 .KEY MESSAGES... - Hot and humid conditions will continue for one more day before a welcome break arrives later in the week. A Heat Advisory remains in effect for the entire area through early this evening. - Scattered to numerous thunderstorms will develop this afternoon into tonight ahead of an approaching cold front. Some of the storms will produce heavy rain, and a Flood Watch has been issued for tonight across parts of southeast MO, southern IL, southwest IN, and northwest KY. - An isolated severe thunderstorm is possible late this afternoon into tonight. Damaging wind gusts will be the primary threat. - Dry, cooler, and much less humid weather will arrive Thursday and continue into the weekend. A small chance of thunderstorms returns to the forecast late in the weekend into early next week for parts of western Kentucky. && .DISCUSSION... Issued at 335 AM CDT Tue Jul 16 2024 Today through Wednesday night...The region is coming under the influence of an increasingly zonal H5 flow, with a surface frontal boundary extending from eastern IA into central MO approaching the area from the northwest. Debris clouds from a decaying MCS across central IL/IN are moving south into the region. Depending on how the decaying MCS evolves, some precipitation may impact far northern and northeastern parts of the forecast area north of I-64 this morning. There is growing uncertainty regarding whether the northern parts of the forecast area will reach Heat Advisory criteria due to lingering clouds and precipitation chances. However, after collaborating with neighboring offices, decided to keep the ongoing Heat Advisory in place for now, but its northern portions may need to be trimmed later today. The main wave of shower and thunderstorms activity looks to arrive late this afternoon through tonight as the cold front approaches from the northwest along with a shortwave trough. This will lead to fairly widespread convective development across central and eastern MO, which will grow upscale into a MCS and move through the forecast area. While bulk shear will be quite limited, high temperatures in the lower to middle 90s and extremely gooey dew points in the upper 70s to lower 80s should allow for robust instability to develop by this afternoon. SPC`s Day 1 Convective Outlook includes a marginal risk of severe thunderstorms across the entire forecast area, and that looks reasonable. The primary severe risk will be isolated damaging winds from downbursts and any linear segments that can organize. With the frontal boundary sagging into the region tonight into Wednesday morning, training thunderstorms and heavy rain will become the main concern. Based on the latest WPC QPF and HREF QPF probabilities, opted to expand the inherited Flood Watch to include parts of northwest KY, more of southern IL, and the Ozark Foothills of southeast MO (in addition to the existing Flood Watch in southeast IL and southwest IN). In the Flood Watch area, most areas stand to get a broad brush of 1.5-3.0" of rain, with locally higher amounts possible. This would be enough rain to cause flash flooding issues if realized. Locations further south and outside of the Flood Watch stand to receive a healthy rain as well, mainly 0.5-1.5". Did not adjust the timing of the Flood Watch from the initial 00-12z Wednesday timing, but some locally heavy rain may linger into the 12-18z Wednesday period in southwest IN and northwest KY. Rainfall rates will trend down during the day on Wednesday as the better forcing moves east of the region. However, scattered to widespread showers and thunderstorms will linger through much of the day. This will keep high temperatures limited to the lower to middle 80s. The greatest coverage in precipitation will gradually shift from north to south as the cold front clears the region. Thursday through Saturday...Canadian high pressure will dry us out for the latter half of the work into the weekend. Cannot rule out a few AM showers along the KY/TN border Thursday morning, but the great majority of the region will be dry by this point. High temperatures will be delightfully cool for the middle of July, in the upper 70s to lower 80s! Low temperatures Thursday night will be just as refreshing, falling into the upper 50s to lower 60s. Temperatures will moderate slightly Friday and Saturday, climbing into the lower to middle 80s. However, humidity levels will remain very comfortable. Overnight lows Friday and Saturday night will stay mainly in the lower 60s. Sunday and Monday...Model guidance has trended a bit more unsettled for this period, especially for parts of west KY. The culprit for this will be a plume of tropical moisture that will be pulled northward from the Gulf of Mexico. The moisture will be hard- pressed to advance much further north than the Tennessee River Valley due to high pressure positioned to the north. However, isolated to widely scattered thunderstorms look to return to the forecast in the southern KY Pennyrile region Sunday and Monday. High temperatures will still be slightly cooler than normal, reaching the lower to middle 80s. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 646 PM CDT Mon Jul 15 2024 VFR conditions are anticipated through much of Tuesday. Remnants of overnight convection to the north of the area will pose the potential for scattered showers and thunderstorms across northern reaches of the area late tonight into Tuesday morning, impacting mainly KMVN and KEVV. Scattered thunderstorm development is also possible late Tuesday afternoon into Tuesday evening across the entire region. Southwest winds 5 to 8 knots will increase to 10 knots by late morning and afternoon on Tuesday. Some gusts to 15 knots are also expected. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...Heat Advisory until 8 PM CDT this evening for ILZ075>078- 080>094. Flood Watch from this evening through Wednesday morning for ILZ075>078-080>089. MO...Heat Advisory until 8 PM CDT this evening for MOZ076-086-087- 100-107>112-114. Flood Watch from this evening through Wednesday morning for MOZ076-086-087-100-107-108. IN...Heat Advisory until 8 PM CDT /9 PM EDT/ this evening for INZ081-082-085>088. Flood Watch from this evening through Wednesday morning for INZ081-082-085>088. KY...Heat Advisory until 8 PM CDT this evening for KYZ001>022. Flood Watch from this evening through Wednesday morning for KYZ014-018-019. && $$ DISCUSSION...DWS AVIATION...RJP