009 FXUS64 KBMX 261022 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 422 AM CST Sat Jan 26 2019 .SHORT TERM... Today through Monday Afternoon. A shortwave trough is currently just to our west and will slide through this morning. Precipitation is very little and barley making it to the surface. Temperatures have dropped off quite substantially tonight due to slightly slower movement and clouds not working in as quickly. With the slightly drier airmass in place over the area the precipitation will remain scattered in nature and will generally be in the form of snow flurries for the northern third if the area. The best chances at seeing any visibility decreasing snowfall will be across the far north, generally from Jasper to Gadsden line. This system works out late morning and then we will see decreasing clouds through the rest of the afternoon and into the evening hours. High pressure continues to build over the region through the weekend with small shortwaves sliding along the northern edge of the high pressure. As the high pressure slides to our east we will begin to get a southerly flow and will be able to warm back up some by the first of the week. By Monday we will see temperatures in the 50s and even some lower 60s in the south ahead of a potential weather impact to be discussed below. 16 .LONG TERM... Monday night through Friday. A deep longwave trough will be in place Monday night with upstream vorticity maxima digging toward Alabama. A cold airmass will be racing southward across the Plains and Midwest with a tightening temperature gradient along an approaching cold front. The front should largely be void of precipitation at 6PM Monday, but west- southwest 850-500mb flow should result in quality moisture advection. A sharpening shortwave and the nose of an approaching upper-level jet should induce isentropic lift and 850-500mb frotogenesis, causing post-frontal precipitation to break out to our west. Operational and ensemble model guidance remain in good agreement with this scenario which may feature a rapid transition from rain to snow on Tuesday morning as the front sweeps through. Between the GFS and ECMWF/NAM, there are some key differences with the handling of the shortwave and strength of the cold airmass. At face value, the ECMWF/NAM solution would yield a high impact for areas near and north of I-20, due to the potential for convective snow and temperatures falling into the 20s. The GFS appears flatter with the trough and warmer, with less overlap of cold air and precipitation. My hunch is that the GFS is a little too flat, and our forecast will lean toward the more bullish ECMWF/NAM idea. Snowfall amounts up to 1.5 inches appear possible near and north of I-20 with amounts dropping off quickly to the south and east. Higher amounts cannot be ruled out with future updates. Though amounts are not expected to be particularly impressive, impacts could be relatively high if temperatures fall below freezing before the snow ends. Dry conditions should return for Tuesday night through Thursday with the potential for temperatures falling into the upper teens Wednesday morning and/or Thursday morning across the North. Models are hinting at the potential for precipitation on Friday due to warm advection aloft. For now, only a slight chance of rain has been included, but cold air will be lurking nearby. 87/Grantham && .AVIATION... 06Z TAF Discussion. VFR conditions are anticipated through the period. A weak upper level disturbance and associated dissipating front will swing by to our north. There will be an increase in moisture/clouds on Saturday, mainly north. On Saturday, winds will start of light out of the north northwest and back to the west northwest at 5-7kts, but there be some variable directions at times. Clouds will build and we will likely experience 5k-7k ft ceilings at the northern terminals. 75 && .FIRE WEATHER... Rain-free conditions are expected through the weekend, and RH values should stay above critical values. There are no fire weather concerns with moist ground conditions in place. The next chance of precipitation arrives Monday night through Tuesday with the passage of a strong cold front. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 49 28 53 32 57 / 10 0 0 0 10 Anniston 50 32 54 33 57 / 10 0 0 0 10 Birmingham 49 34 55 34 60 / 10 0 0 0 10 Tuscaloosa 52 33 58 35 62 / 10 0 0 0 10 Calera 50 33 55 34 60 / 10 0 0 0 10 Auburn 51 35 55 35 58 / 0 0 0 0 0 Montgomery 54 34 59 35 63 / 0 0 0 0 10 Troy 55 34 59 35 62 / 0 0 0 0 0 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$