Area Forecast Discussion
Issued by NWS Huntsville, AL
Issued by NWS Huntsville, AL
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784 FXUS64 KHUN 140158 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 858 PM CDT Sat Jul 13 2024 ...New NEAR TERM... .NEAR TERM... (Tonight) Issued at 858 PM CDT Sat Jul 13 2024 Isolated showers that formed across parts of the area in the afternoon have dissipated. The convection formed, thanks to strong daytime heating and resultant instability. While showers did not directly impact the official sites, a number of backyard weather stations around the Tennessee Valley have recorded amounts ranging from a few hundredths of an inch, upwards to over 1/2 inch in some spots. High temperatures across the area earlier soared into the mid 90s to 100 degree. Muscle Shoals and Decatur apparently heated to 100 degrees, with 98 the high in Huntsville. Other locations were more in the mid 90s. Temperatures as we near 9 PM have cooled into 70s and 80s. Given the heat from earlier and a very warm airmass in place, lows by daybreak Sunday should cool into the lower to mid 70s, with light winds. Fog could become an issue in the overnight mainly in/near locations that received a "wetting" rain (~> 1/10 of an inch). But the overall area has been trending on the dry side, with most if not all of the moisture absorbed into the ground and vegetation. Big changes to the on-going forecast are not needed at this time. && .SHORT TERM... (Sunday through Monday Night) Issued at 1238 PM CDT Sat Jul 13 2024 The weak vorticity center in eastern TX into northern LA/southeast AR is forecast to lift northeast into northern MS and AL Sunday and linger through Tuesday. This will continue to erode the already weak capping inversion. Thus, we will maintain a 10-15% PoP Sunday once again for isolated convection, and slowly increase those PoPs into Monday, especially for the southern counties in our forecast area. Steep low level lapse rates will create a favorable environment for gusty winds with associated downdrafts. Will go with near persistence temperature forecasts with highs in the middle 90s to around 100. With strong mixing, dew points will continue to be halted in the upper 60s to around 70 during the afternoon hours, producing heat index values below 105 degrees for most areas. && .LONG TERM... (Tuesday through Friday) Issued at 417 AM CDT Sat Jul 13 2024 The most recent suite of global models suggests that conditions on Tuesday will be very similar to Monday, with highs in the m-u 90s, heat indices in the 100-105F range and a 20-30% coverage of afternoon showers and storms (which will likely be slow-moving and capable of producing heavy rainfall in localized areas). By Wednesday, however, our region will experience increasing influence from an amplifying northern stream trough, which is predicted to spread northeastward from Ontario into the Canadian Maritime provinces by Thursday night/Friday morning. The cold front related to this trough is expected to advance southeastward during the middle portion of the week, with the prefrontal wind shift axis expected to slowly cross the TN Valley at some point Wednesday night or Thursday. A higher (60-80%) POP for showers and thunderstorms is warranted as early as Wednesday afternoon given the position of the front to our north and strengthening WNW flow aloft. The greater coverage of convection will likely continue on Wednesday night/early Thursday morning, before becoming focused to the south/east of the wind shift (across our southeastern zones) on Thursday afternoon. Due to some uncertainty regarding the location of the front before it eventually stalls, we will maintain a medium chance POP in the southeastern portion of the CWFA on Thursday night and Friday. Fortunately, a modest coverage of clouds and precipitation should keep highs in the u80s-l90s from Wednesday-Friday, lowering the heat risk region- wide. && .AVIATION... (00Z TAFS) Issued at 648 PM CDT Sat Jul 13 2024 VFR weather should continue across the area. Strong daytime heating and resultant instability has resulted in a few showers forming over the past few hours. Shower activity should fade as we go into the later evening and overnight. Patchy fog cannot totally ruled out before daybreak in and near locations that received measurable rainfall. More strong heating should result in more CU/TCU forming towards Sun afternoon. Confidence is too low on adding showers Sun afternoon this issuance. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...RSB SHORT TERM....17 LONG TERM....70/DD AVIATION...RSB