686 FXUS64 KBMX 240943 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 343 AM CST Sun Nov 24 2019 .SHORT TERM... /Updated at 0343 AM CST Sun Nov 24 2019/ Through Tonight. Cold air is filtering into the area this morning and continues to bring low level stratus with it. There are still some pockets of drizzle, but most of this has moved to I-65 and areas east. Look for the majority of this drizzle to be done by 6 am, with only the far northeast possibly seeing anything at all. Clouds will hang tough through the morning in the east. Skies will clear out tonight and temperatures will drop off into the 30s generally across all of the area. Some upper 20s will be possible in the far northern and protected areas. 16 .LONG TERM... /Updated at 0343 AM CST Sun Nov 24 2019/ Monday through Wednesday: Quasi-zonal but broadly cyclonic flow will be in place aloft on Monday, downstream of a trough digging into the Four Corners region. A weak wave in the subtropical jet will provide a few high clouds. Southwesterly low-level flow and associated warm advection should allow high temperatures to reach the high side of guidance: the mid to upper 60s. Winds will remain southerly overnight but light, allowing temperatures to fall into the low 40s with some 30s in typically cooler locations. Clouds will begin to increase late in the night. A low-amplitude trough and embedded upper low and a surface low will lift from the High Plains to near Lake Michigan Tuesday/Tuesday night, causing a cold front to move through Central Alabama very late Tuesday night through Wednesday. An intense 135kt mid-level jet streak on the trough's southern flank will lift across the Ozarks to the Ohio Valley Tuesday night. A 45-50kt LLJ will move from the Lower Mississippi Valley to Alabama Tuesday night. Various subtropical impulses in the southwest flow aloft will move across Central Alabama during the day on Tuesday. The associated increase in mid-level moisture/isentropic lift will result in rain chances increasing Tuesday afternoon, especially in the northwest counties as profiles become saturated. Several limiting factors are expected to prevent a threat of severe storms despite favorable shear profiles for supercells. The main limiting factor will be instability. Moisture return in the wake of the current cold frontal passage over the Gulf will be limited, with dew points remaining in the 50s during the afternoon and early evening hours. As low 60s dew points begin to move in during the late evening and overnight hours, weak mainly elevated instability may develop allowing for isolated thunder but surface- based CAPE will be negligible, with precipitation associated with the subtropical impulses also serving as a stabilization factor. By the time higher dew points arrive early Wednesday morning, low- level flow will be veering and weakening. In addition, notable 500mb height rises indicative of synoptic subsidence will be present throughout the event as a subtropical ridge centered near Cuba strengthens, and the trough lifts away from the area. Therefore, severe storms are not expected at this time, with any stronger activity that develops off to our west expected to weaken as it arrives, but will continue to monitor. Plentiful moisture with PWATs around 1.85 inches will be present along with enough low to mid- level lift to support widespread precipitation Tuesday night and Wednesday. Temperatures will also warm into the 70s across the southern counties Tuesday and Wednesday due to southerly flow ahead of the front. Thursday through Sunday: A strong 593 decameter subtropical ridge will strengthen over the Gulf Thursday/Friday, with a ridge axis extending northward across the eastern CONUS. The front will stall near the Gulf Coast by Thursday as it encounters the ridge, before beginning to lift northward as a warm front on Friday. This will result in cooler temperatures on Thursday and a warming trend for Friday, though easterly flow north of the front will prevent more significant warming. Another deep trough digging along the West Coast will cause the cutoff low currently well west of the Baja peninsula to eject northeastward with its remnant vorticity riding over the ridge. Mid-level isentropic lift/warm advection may allow for some rain to clip some of our northern counties Thursday night/Friday, though the bulk of the rain appears that it will remain northwest of the area. The large trough over the western CONUS will eventually push eastward and break down the ridge next weekend, sending another low pressure system from the Plains to the Midwest with a trailing cold front. Typical uncertainties exist with the speed of this system, and suspect the slower solutions may be more likely given the strength of the ridge. It appears that this system will have more moisture/instability than previous systems as the mid-week cold front will not make it all the way through the Gulf, especially if the slower solutions are correct. There are also some indications of steeper mid-level lapse rates associated with an EML. At this time predictability is too low to mention in the HWO this far out but will keep an eye on it. 32/Davis && .AVIATION... 06Z TAF Discussion. Cold air stratocumulus has been advecting southeast across central Alabama as a short wave trof traverses the area. A band of light rain or drizzle has been falling near the I-65 corridor, reducing vsbys to 3 miles and lowering cigs blo 1000 feet agl. The has already moved past KBHM and KEET and will not likely impact any other central Alabama TAF sites overnight. The cig heights have been varying from hour to hour, but have mostly been below 3000 feet agl, with lcl cigs near 1000 feet. The back edge of the clouds was near the Alabama and Mississippi state line. The clouds will continue to erode overnight from west to east, reaching the I-65 corridor by 11z. By 14z expect all TAF sites to report clear or sct conds. 58/rose && .FIRE WEATHER... Dry and cooler conditions are expected today, with a warming trend for Monday and Tuesday. A cold front will bring another round of widespread rain chances late Tuesday afternoon through Wednesday. Critical fire weather conditions are not expected. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 56 31 62 37 65 / 10 0 0 0 30 Anniston 56 33 65 39 67 / 10 0 0 0 20 Birmingham 56 36 65 42 67 / 0 0 0 0 30 Tuscaloosa 58 35 66 43 70 / 0 0 0 10 40 Calera 57 34 65 41 69 / 0 0 0 0 30 Auburn 58 35 63 40 67 / 0 0 0 0 10 Montgomery 59 35 69 43 74 / 0 0 0 0 20 Troy 60 36 67 42 72 / 0 0 0 0 10 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$