533 FXUS64 KBMX 202036 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 236 PM CST Sun Jan 20 2019 .SHORT TERM... Through Tonight. Clouds have been rapidly eroding this afternoon as drier air advects southward into Alabama. Skies should be mostly clear by sunset. Despite sunshine this afternoon, temperatures have struggled to rise with readings mostly in the 30s. Winds will stay up tonight around 5 mph, which will help keep temperatures from falling into the upper teens. 58/rose .LONG TERM... Monday through Sunday. Upper level ridging builds in across the Eastern US Monday and Tuesday as surface high pressure slides through the Great Lakes region into the Tidewater region of the Coastal Mid-Atlantic. Our next system is off to the west at this point, with a deep positively- tilted trough stretched from the Northern Plains to the 4 Corners region by Tuesday morning. A surface low has developed and tracks through the Central Plains into the Ohio River Valley through the day on Tuesday into early Wednesday morning. A cold front stretches southward from the surface low and will approach Central AL by late Tuesday evening, increasing rain chances. Rain becomes widespread on Wednesday as the front pushes through our area. Overall, instability with this system remains limited, but models do hint at some elevated instability working in, so I've added a slight chance for thunderstorms in the widespread rainfall. Guidance suggests that the upper trough could trend more towards a neutral tilt over Central AL as a secondary low forms just to our east late Wednesday night into Thursday. This will help to bring the sub-freezing air in behind the cold front fairly quickly. The majority of any precip should be out of the area before temperatures drop well below freezing, but I can't rule out a very brief change over from rain to snow flurries in that 32-36 degree range as the system departs from midnight to sunrise Thursday. This will likely only take place in our northwestern counties as the freezing temperatures don't really make it any further south than the I-59 corridor before Thursday morning. The cold front is well east of our area during the day on Thursday with cooler and drier air being advected into Central AL. Friday morning temps will likely be at or below freezing for our entire area. The synoptic pattern remains unchanged from Friday through the weekend, with an expansive upper level trough spread from the Rocky Mountains all the way to the Atlantic Coast. This will keep a relatively cooler air mass over the Deep South for the end of the week. NAEFs highlights much of the region in the bottom 10th or bottom 2.5th percentiles for mean temps and mean geopotential heights with values roughly 2 standard deviations below the climatological mean for this time of year. Essentially, this adds confidence in the overall forecast for cold weather in the extended forecast. Another clipper system dips through the Upper Plains and into the Southeast sometime Saturday evening or Sunday, but guidance varies substantially on the timing. Depending on when it comes through and the temperatures at the time, I can't rule out some mixed precip, so I've had to include mention in the forecast. However, confidence is extremely low 7 days out for any mixed precip. I'm more confident in it remaining all liquid at this time. Later Sunday into early part of next week, the trough axis shifts east of us and we get some synoptic height rises with the surface high pressure building in. Therefore, I've started a drying trend in the PoP's, clearing out any precip by Sunday night. Expect this forecast for the weekend to change as models come into better agreement on timing. 25/Owen && .AVIATION... 18Z TAF Discussion. Widespread low clouds blanketed central Alabama this morning. No pcpn was associated with the cloud cover as the moist layer is shallow. The MVFR cigs will erode between 18z and 21z, starting across north Alabama and working southward. Sfc winds will also be an issue with brisk northwest speeds of 10-15 kts with gusts to 25 kts thru the afternoon. Wind speeds will diminish to less than 10 kts by 00z, but stay up around 3-6 kts overnight. 58/ROSE && .FIRE WEATHER... Windy day across the area today with sustained winds 15-20 mph with gusts to 35 mph. Temperatures remain on the cooler side. Clouds will decrease by this afternoon. Min RH values remain well above critical values, so there are no fire weather concerns. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 21 41 27 52 43 / 0 0 0 10 70 Anniston 22 43 29 53 44 / 0 0 0 0 70 Birmingham 23 45 33 55 47 / 0 0 0 10 70 Tuscaloosa 26 48 33 56 48 / 0 0 0 20 80 Calera 24 46 32 55 47 / 0 0 0 10 70 Auburn 25 46 31 54 46 / 0 0 0 10 40 Montgomery 27 50 32 58 49 / 0 0 0 0 60 Troy 25 51 32 59 50 / 0 0 0 0 40 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$