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Area Forecast Discussion
256 FXUS64 KHUN 262318 AAA AFDHUN Area Forecast Discussion...UPDATED National Weather Service Huntsville AL 618 PM CDT Mon Sep 26 2016 .UPDATE... For 00Z TAFs. && .DISCUSSION... (Issued 313 PM CDT Mon Sep 26 2016) Latest water vapor imagery shows a upper level low over the northern Great Lakes region, with upper level ridging over much of the western CONUS. At the surface, a cold front extended from the parent low over the Great Lakes, southwestward into the lower MS Valley. A line of showers and storms that developed earlier in the day has reached the far SE portion of the CWA and would expect most of this activity to push out of the area by sunset. The main cold front has reach through the western half of the CWA, though lingering post frontal showers were noted with the main trough axis over portions of western TN and northern MS. As this activity moves east, it may clip the northern portion of the area, however current thinking is that most of the area will be rain free this evening and overnight. Northerly flow behind the front will bring in the colder air during the overnight hours, with forecast lows reaching into the upper 50s to lower 60s. The upper level low will begin to dig southward on Tuesday and Wednesday. There are some slight discrepancies with how far south the front reaches, and whether this provides additional lift for showers across the SE. However, feel that the front will make it south of our area overnight and the isentropic analysis shows little to no forcing for ascent. Therefore will continue with a dry forecast after 06Z this evening. Temperatures on Tuesday and Wednesday will be very nice compared to what we have observed over the last few weeks, with highs expected to remain upper 70s to lower 80s and lows around 50. Precip chances will increase slightly on Wednesday night and into Thursday as the upper low reaches into the Ohio Valley and a weaker vort max rotates around the base of this trough over the NE portion of the area. Not expecting much coverage as moisture will remain limited. However, given the stronger forcing, there may be an isolated light shower or two. This will also send a reinforcing cold front through the area, and forecast highs may have a tough time warming above the mid 70s on Thursday and Friday. The upper low will begin to shift northward overnight Friday, with near zonal flow expected across the TN Valley over the weekend. Temperatures are expected to moderate slightly, with highs warming into the low to mid 80s by Sunday. 73 && .AVIATION... For 00Z TAFs: Cold front is now mainly e of the two main terminals, with just a few lingering shra in its wake. What precip is left should diminish over the next 1-2 hrs with the loss of daytime heating. This should then leave mainly mid/high clouds in place over much of the region, with VFR conds prevailing into the evening period. Cigs may lower closer to MVFR levels heading into the overnight hrs before recovering Tue morning, and then scattering or clearing with the onset of the afternoon period. Sfc flow will also turn toward the n/nnw going into the late morning hrs. 09 && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ For more information please visit our website at weather.gov/huntsville.