Area Forecast Discussion
Issued by NWS Birmingham, AL
Issued by NWS Birmingham, AL
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517 FXUS64 KBMX 131742 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 1242 PM CDT Sat Jul 13 2024 ...New SHORT TERM, AVIATION... .SHORT TERM... (This evening through Sunday) Issued at 1201 PM CDT SAT JUL 13 2024 The heat has returned across Central Alabama, thanks to a building upper level ridge over the Florida Big Bend. Most locations are already observing low to mid 90s as of midday. We`re well on our way to the upper 90s areawide, and would not be surprised to see a few spots hit 100 before all is said and done. Slowly but surely, we`re introducing a little bit more moisture both at the surface and aloft. Looking back at the 12z sounding from the past couple of days, you can certainly see the amount of dry air aloft has been shrinking, especially between the 700-500mb levels. With additional moisture and some lift caused by a weak shortwave moving off to our north, isolated showers and perhaps a storm can`t be ruled out this afternoon. I`ve gone ahead and added in a slight chance PoP across the northern tier of counties, as well as across the far south, where low-level moisture is greatest. Heat indices are expected below criteria, but will still rise into the 100-103 degree range. Following a calm and mostly clear night with lows in the 70s, the heat will return once again during the day on Sunday. One difference will be the return of higher dewpoints and humidity as low-level flow becomes southwesterly over the region. As highs top out in the upper 90s to near 100 degrees, we`ll be very close to Heat Advisory criteria, especially in the urban heat islands and more locations along and south of the I-85 corridor. For now, will opt to hold off on a Heat Advisory, but that could change if higher dewpoint trends are realized. Regardless, folks should always take the proper precautions to prevent heat related illness, especially with prolonged heat expected to last into early next week. Rain chances will be a tad higher tomorrow afternoon due to the moisture increase and presence of a weak upper shortwave drifting off to our northwest. Scattered convection will be possible across the far southwest and southern counties with isolated development elsewhere. 56/GDG && .LONG TERM... (Sunday night through next Friday) Issued at 324 AM CDT SAT JUL 13 2024 Low amplitude upper-level flow will stretch across the CONUS at the beginning of the period featuring a ridge across the West and weak troughing across the East. However, low-level ridging will remain positioned across the Southeast where an ongoing period of above-average temperatures supports expanding drought across the Tennessee Valley. Afternoon highs in the mid to upper 90s are forecast Monday and Tuesday. Making matters worse, mean low-level flow will favor a southwesterly direction allowing for increasing boundary layer moisture. PWs will rise toward 2.0" with dewpoints in the low 70s. Thus, daytime heat index values will likely meet/exceed advisory criteria. Our saving grace will be the increasing chance for afternoon convection owing to increasing moisture/instability. Furthermore, convective coverage could be enhanced by the presence of a subtle upper-level low (barotropic instability) progged near the ArkLaMiss Monday and Tuesday. PoPs were increased a bit, but still remain below the "likely" category until confidence increases that we`ll see meaningful coverage. Temperatures begin a slow (and merciful) decrease mid to late next week in association with a more prominent mid- to upper-level trough progged to advance across the Great Lakes region on Wednesday. This will feature embedded shortwaves that will swing closer to our region on Thursday as the pattern aloft becomes more amplified. Meanwhile, moisture values will increase a bit more Wednesday, generally ahead of an associated front that approaches the Tennessee Valley on Thursday. With the aid of synoptic forcing, convective rain chances are 60-70% for Wed/Thu, and hopefully this will provide beneficial rains to the forecast area. Rain chances remain elevated along the progressing front into Friday, with drier air moving into the area across the north. It doesn`t sound like much, but there could be enough mid-level flow (around 20-25 kts) for a few stronger storms on these days as well, should other mesoscale factors work out. 40/Sizemore && .AVIATION... (18Z TAFS) Issued at 1201 PM CDT SAT JUL 13 2024 VFR conditions are expected through the forecast period. Isolated showers with a few storms aren`t out of the question, but certainly not enough to mention in the TAFs through 18z Sunday. Winds will remain light or calm through the period. 56/GDG && .FIRE WEATHER... Hot and dry conditions will remain in place through the weekend. Min RHs on Saturday and Sunday will be in the 30 to 35 percent range, though winds should remain generally light to calm. Chances of isolated showers and storms return on Sunday, with a more humid air mass returning next week. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 70 99 72 98 / 0 20 10 30 Anniston 72 97 74 96 / 0 20 10 30 Birmingham 74 99 76 98 / 0 20 10 30 Tuscaloosa 74 99 74 97 / 0 20 10 40 Calera 74 99 74 97 / 0 20 10 30 Auburn 74 97 75 96 / 0 20 10 40 Montgomery 74 99 76 98 / 10 30 10 50 Troy 73 99 74 97 / 10 30 10 50 && .BMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...56/GDG LONG TERM....40 AVIATION...56/GDG