725 FXUS64 KBMX 041528 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 1028 AM CDT Sat Jul 4 2020 .UPDATE... Morning Update. && .SHORT TERM... /Updated at 1006 AM CDT Sat Jul 04 2020/ Showers and thunderstorms will still be expected through the afternoon and evening today...with the main timing between 2 pm and 10 pm tonight. The main adjustments to the forecast were to increase the coverage and percentage of rain chances across central Alabama...with confidence decreasing that the rain will stay mainly in the southwest and northeast counties. Forcing will be the greatest limiting factor for how much develops in central Alabama...but enough upper level support and instabilities have led to the decrease in confidence that the activity will remain in teh far southwest or northeastern counties. Soundings this morning had plenty of dry air with DCAPE values at or above 1200 J/kg, and instabilities 1500 - 2500 J/kg. With this in mind, any storms that do develop could be strong to severe with damaging winds as the main threat. Otherwise temperatures look to be on track with clouds increasing through the day keeping the high temperatures in the low 90's. South to southeast flow will keep high humidities and heat indices close to the upper 90's and in the triple digits in a few places this afternoon. 24 Previous short-term discussion: /Updated at 0327 AM CDT Sat Jul 04 2020/ Today through Sunday. The 4th of July will be marked by plenty of heat and humidity with a chance of afternoon storms. Daytime heating will be the main trigger for storms today. The better chances for rain today will be across the far southwest and northeast counties. A weak upper low over southeast Louisiana will bring better lift for coastal convection which will extend northward into southwest Alabama. A weak upper disturbance will track westward across northern Georgia and into northeast Alabama this afternoon as the upper flow remains out of the east. Similar to yesterday, storms will be moving from east to west. Steep low level lapse rates and SBCAPE values near 2500 J/kg this afternoon will be sufficient for a few strong storms with wind gusts of 35 to 45 mph. The convective activity will diminish in areal coverage and intensity early this evening with only isolated showers and thunderstorms expected by 9 PM. The rain should be gone by midnight. Some big changes to Sunday forecast as models now show an intrusion of drier mid level air from Georgia. This will keep higher rain chances confined to the southwest counties with pops around 60 percent, with 30-40 percent rain chances elsewhere. Temperatures will be on the warm side again today with highs in the lower 90s and heat indices near 100 degrees. A slight cool down on Sunday. 58/rose .LONG TERM... /Updated at 0327 AM CDT Sat Jul 04 2020/ Sunday night through Friday. A warm/moist air mass will build in across the area Sunday night and continue through most of the upcoming week. PWATs are forecast to be in the 2-2.2" range, which is on the upper end of climatology for this time of year. Couple this with a persistent weak upper level low, that while becoming more broad and diffuse, will likely provide enough forcing to support more widespread showers/thunderstorms during the afternoons. I've trended thunderstorm chances up to 90% for Monday, then to 80% Tuesday and Wednesday (mainly in the afternoons). Overnight periods will see a decrease in coverage, but I wouldn't be surprised to see at least some shower activity linger through the night on Monday and Tuesday. With the higher rain chances, we're likely to see a smaller diurnal swing in temperatures with highs in the mid to upper 80s and lows in the low to mid 70s. Models continue to hint at a pattern change late in the week, though guidance hasn't shown much temporal consistency in when that would take place. The ridging to our west becomes more amplified, pushing the upper level low that will be over us slightly more eastward into Southern GA late Wednesday through Thursday. If this takes place as guidance suggests, it would put us in the periphery of the high pressure, leading to at least some subsidence and a slight decrease in PoPs. With the decrease in rain chances, unfortunately, we'll be looking a slight warming trend towards Friday. Depending on how the temps/dewpoints trend by the end of the week, we could see a return of afternoon highs in the upper 80s to low 90s and heat indices reaching/exceeding 100 degrees. 25/Owen && .AVIATION... 12Z TAF Discussion. Some early morning fog and patchy low clouds, but conds should improve at all sites by 13z. Little or no pcpn expected thru 18z. Diurnal heating will trigger sct tstms between 18z and 00z, with best chances across the northeast. Handled most sites with a PROB30 group between 20z and 24z. Fair conds after 01z. 58/rose && .FIRE WEATHER... The warm/moist airmass will also continue to be in place this weekend and into the early part of next week. Rain/thunderstorm chances increase for the first half of next week. Min RHs will be in the 50-60% range through Sunday, rising to 60-80% for next week. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 91 71 91 69 86 / 50 30 40 30 80 Anniston 91 71 91 70 85 / 40 30 30 30 90 Birmingham 92 73 91 72 87 / 40 30 40 30 90 Tuscaloosa 92 73 92 72 87 / 50 30 40 40 90 Calera 91 72 90 71 85 / 40 20 40 40 90 Auburn 90 71 91 71 83 / 30 20 40 50 90 Montgomery 92 72 91 72 85 / 50 30 50 60 90 Troy 92 71 90 72 86 / 40 30 60 60 90 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$