461 FXUS64 KBMX 260350 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 950 PM CST Wed Dec 25 2019 .UPDATE... Evening Update. && .SHORT TERM... /Updated at 0943 PM CST Wed Dec 25 2019/ High pressure remains over Central Alabama, but centered just to our east. Lower level winds become more south and southwest through Thursday, mainly west. We will experience an increase in lower level cloudiness west and mainly upper level clouds east. Since this increase has not quite started yet in the lower levels, temperatures were able to cool nicely after sunset. At 9 pm, a large temperature gradient exists from east to west, the near 40 east and mid 50s southwest. The lows will mirror this range and should not cool off too much more. A few upper 30s possible east but the range will generally be from 40 to 52 degrees.A few locations east may experience some patchy fog overnight. The fog will form in the normally cooler valley locations and near water bodies. 75 Previous short-term discussion: /Updated at 305 PM CST Wed Dec 25 2019/ Through Thursday. Surface high pressure along the east coast...and upper level ridging...will continue to provide dry weather for at least another day or so. Mid to high level clouds will filter the sunshine a bit, but the air mass remains supportive of above normal high temperatures. /61/ .LONG TERM... /Updated at 326 AM CST Wed Dec 25 2019/ Friday through Wednesday. Ridging in the east begins to break down slightly late Thursday into Friday as the trough in the Western CONUS deepens and shifts eastward. For Central AL, the wedging pattern will linger at least through late Friday, which will provide plenty of cloud cover and keeping diurnal temps on the milder side. Meanwhile, the deep trough across the Western US shifts eastward across the Rockies Friday evening. A surface low develops and lifts quickly northeastward through the Central Plains early on Saturday. This lifts an effective warm front northward through Central AL leading to some increased chances of rain showers, especially Saturday afternoon and evening. Guidance has come into much better agreement on the timing of this system for Sunday, considering it's still 5 days out. The cold front pushes across Mississippi overnight Saturday into early Sunday morning, and is expected to move through Central AL during the day on Sunday.The low pressure system might already have started occluding in the Upper Midwest as it continues to lift into the Great Lakes Region when the frontal passage is projected for Central AL. This leads to some uncertainty on the overall dynamics as it pertains to any severe weather threat. Models also have quite the spread on forecast instability values. The ECMWF is much more aggressive and is also roughly 6 hours slower in timing. The GFS shows very limited instability due to the warmer air aloft, and therefore much lower lapse rates. All in all, too much uncertainty and potential limiting factors in the thermodynamics exist for me to add mention for severe weather Sunday; however, it's worth continuing to monitor as it doesn't take much instability given the high amount of shear we'll have in place with this system to produce a severe weather situation this time of year. The cold front is expected to push east of Central AL overnight Sunday into Monday, tapering of any rain chances from west to east. The start of next week looks to remain dry as the cooler and drier air mass builds in. Guidance suggests another system could push into the area around New Years, but details remain uncertain so for now, I'll gradually increase PoPs Tuesday night into Wednesday. 25/Owen && .AVIATION... 00Z TAF Discussion. VFR TAFs are forecasted for the next 24 hours. We warmed up nicely on this Christmas day and fog should not be as much of an issue. High clouds are present on satellite at this hour going through the upper southwest flow. No precipitation is expected though. Cloud heights will lower some in the west during the day Thursday, but should still be VFR. 08 && .FIRE WEATHER... High pressure will provide dry weather through the rest of the weekend. The next rain chance will come over the weekend, as a cold front approaches the region. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 42 67 46 64 49 / 0 0 0 10 10 Anniston 42 69 47 66 51 / 0 0 0 10 10 Birmingham 47 68 51 65 54 / 0 0 0 10 10 Tuscaloosa 50 68 52 67 54 / 0 0 10 10 10 Calera 48 68 50 65 52 / 0 0 0 10 10 Auburn 44 68 51 65 53 / 0 0 0 10 10 Montgomery 48 71 53 69 54 / 0 0 0 10 10 Troy 46 71 53 69 55 / 0 0 0 10 10 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$