Area Forecast Discussion
Issued by NWS Birmingham, AL
Issued by NWS Birmingham, AL
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099 FXUS64 KBMX 140014 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 714 PM CDT Sat Jul 13 2024 ...New 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 233 PM CDT SAT JUL 13 2024 Made some minor adjustments to rain chances in the extended, but forecast trends are on track. Expect rain chances to increase each day, as moisture increases and troughing develops across the eastern CONUS by the end of the week. 14 Previous long-term discussion: (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... (00Z TAFS) Issued at 654 PM CDT SAT JUL 13 2024 VFR conditions are expected generally for the 24 hour forecast across C AL. Winds will become light/variable to near calm overnight. There are a few isolated showers on the radar at this time.This will decrease after sunset. Will monitor for amendments, but chances are too small include at this time for mainly TCL if any. Some lingering mid level residual clouds from peripheral convection will be around for part of the evening. Winds should be generally light/variable during the day Sun, but a few W-SW winds during peak afternoon heating/mixing at 5-7kts are possible. Cloud cover will be minimal, mainly fair weather cumulus with heating. There will be a chance for isolated to scattered afternoon diurnal storms across much of C AL. Will only mention a prob30 for late afternoon TSRA mention at MGM for now. Note: AMD LTD TO WIND AND VIS at KASN UFN due to missing ceilings. 08 && .FIRE WEATHER... Other than isolated to scattered rain coverage Sunday afternoon, expect warm and dry conditions to continue. Rain coverage begins to increase each day next week, as moisture increases. Min RHs Sunday will be in the 30 to 40 percent range, light to calm 20ft winds. Minimum RH values will be above 35 percent beginning Monday. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 70 99 72 97 / 20 20 20 30 Anniston 72 97 74 95 / 10 20 20 40 Birmingham 74 99 76 96 / 20 20 20 40 Tuscaloosa 74 99 74 95 / 20 20 20 40 Calera 74 99 74 95 / 10 20 20 40 Auburn 74 97 75 95 / 10 20 10 50 Montgomery 74 99 76 96 / 10 30 20 50 Troy 73 99 74 95 / 20 30 20 60 && .BMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...56/GDG LONG TERM....14/40/Sizemore AVIATION...08