016 FXUS64 KBMX 270553 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 1253 AM CDT Thu May 27 2021 .UPDATE... For 06Z Aviation. && .SHORT TERM... /Updated at 108 PM CDT Wed May 26 2021/ Today through Thursday. Deep-layer ridging is now centered over South Florida with surface high pressure centered over the Florida Panhandle. A trough extends from the Central Ohio River Valley southwest over the Lower Mississippi River Valley. Today. Expect the trough to approach from the west, gradually weakening with time. The combination of the upper level support with continued moistening in the lower levels is supporting scattered shower activity across the western third of the forecast area at this writing. There remains potential for a thunderstorm or two but that chance remains on the low side. The activity will move east with time through the afternoon into our central counties, however, slightly drier conditions aloft are expected to result in a gradual decrease in extent and intensity with time. Highs will range from the low 80s northwest to the mid 90s southeast. Winds will be remain out of the southwest 5-10 mph. Tonight. The trough will continue to move east across the area while shortwave ridging builds in to our west. Enough upper level forcing along with sufficient moisture in the low and mid levels will support scattered to isolated showers across the northern half of the forecast area, though extent and intensity will gradually decrease with time. There may be some patchy fog in areas that receive rainfall today. Lows will be in the mid 60s across the area. Winds will be light. Tomorrow. The trough will move east of the area on Thursday while the flow aloft becomes more zonal. Surface high pressure to our southeast will expand with time northward into the area. Isolated showers will be possible for areas generally east of Interstate 65 and north of Interstate 85 with a smaller coverage elsewhere. Highs will range from the upper 80s northeast to the mid 90s southwest. Winds will be from the southwest 5-10 mph. 05 .LONG TERM... /Updated at 228 PM CDT Wed May 26 2021/ Friday through Tuesday. Main theme of the long term forecast remains unchanged...just freshened up with a few minor tweaks here and there. Increased (and mostly welcome) chances of rain increase through the end of the week as the previously stagnant weather pattern breaks down and heads into a more progressive/active period. Rain chances peak during the day Friday as the combination of diurnal trends and approaching features tap into an abundant source of moisture out ahead of the approaching system. Some question as to how quickly the boundary will work its way southeastward through the forecast area...but a cooler and drier air mass behind the front will give us a reprieve from the unseasonably warm temperatures we've been experiencing this week. As expected...guidance diverges towards the end of the forecast period...with differences on southward placement of the more progressive stream of shortwaves. Either way...it appears that the pattern across the CONUS will remain progressive with the end result favoring the continuation of seasonable conditions. 02 Previous long-term discussion: /Updated at 330 AM CDT Wed May 26 2021/ Friday through Tuesday. An upper level shortwave and associated surface front will be on our doorstep Friday morning, presenting the best chance of rainfall for Central Alabama this forecast period. Height falls are weak with modest jet fields, but surface instability jumps up to more than 1200 J/kg Friday afternoon across the north with PWs over 1.7 inches. Rainfall amounts should remain less than one half inch. Do not expect severe storms, but if the forcing with the short wave slows down a bit and taps into the afternoon instability, could see a few strong storms with heavier rainfall at times. Best rain chances will be confined to the north, closer to upper level dynamics, which will be pulling quickly to the northeast. Activity will slide southward Friday evening, with the front sinking southward overnight. Will need to watch models trends and whether a secondary shortwave rotating around the larger trough enhances showers along the front lingering just to our south Saturday. Will leave low rain chances in for now, but expect conditions to be mostly dry for the holiday weekend. Slightly cooler temperatures are expected behind the front. Highs Sunday and Monday will be back in the low to mid 80s with lows in the mid 50s to lower 60s. Weak ridging builds back into the area early next week, with low rain chances expected Tuesday. 14 && .AVIATION... 06Z TAF Discussion. An upper level trof was currently located across northwest Alabama. Mostly mid level clouds with bases 8-10k ft agl were present along and east of the trof axis. Lower cigs and fog will likely develop between 08z and 13z across west Alabama where low level moisture levels are higher and the proximity of a weak surface trof. IFR cigs possible at KTCL with MVFR cigs as far east as KBHM. Isolated showers will continue thru the early morning hours for areas along and west of I-65. As surface temperatures rise and instability increases, isold to sct tstms will develop in the afternoon along along and east of the upper trof axis. The convection should quickly decrease in coverage by 00z. Note: AMD NOT SKED until further notice at KASN due to ongoing equipment issues. 58/rose && .FIRE WEATHER... With southwesterly winds, moisture gradually increases today and Thursday, and minimum afternoon RH values remain above 35 percent. Light fog is possible early Thursday morning, mainly across the north. Isolated to scattered rain chances expected for much of the area through Thursday, before a cold front brings an increased chance of rain on Friday. Despite recent dry weather, KBDI values remain 300 or less at this time. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 87 66 89 61 80 / 30 10 70 30 10 Anniston 87 68 88 64 82 / 30 10 50 40 20 Birmingham 90 70 90 64 82 / 30 10 60 40 20 Tuscaloosa 93 69 90 65 83 / 20 10 60 30 20 Calera 90 70 87 65 82 / 30 10 50 40 20 Auburn 88 68 87 67 83 / 30 20 30 30 30 Montgomery 92 69 91 68 87 / 30 20 30 30 30 Troy 91 67 91 68 88 / 40 20 20 30 40 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$