844 FXUS64 KHUN 090520 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 1220 AM CDT Fri Oct 9 2020 .UPDATE... For 06Z TAFS. && .NEAR TERM...(Rest of tonight) Issued at 930 PM CDT Thu Oct 8 2020 As of the latest 7 PM CDT update, Hurricane Delta was about 310 miles south of Cameron, Louisiana and was moving to the NNW at 12 mph. It had maximum sustained winds of 115 mph and its central pressure was 956 MB. It still is forecast to move to the NNW before turning to the NNE and directly impacting the extreme southeastern TX or southwestern Louisiana coastline. It does look as though a weakening front sliding southeast from the Ohio valley will help to strengthen the ridging both near the surface and aloft over central Alabama northeast into the Mid- Atlantic states. This should help to keep Delta moving well to our west. Over Tennessee and northern Alabama, this should help to keep dewpoints in the lower 60s primarily. Adjusted lows a tad lower to reflect this given radiational cooling already occurring despite cloud cover. Expect the high/mid cloud cover to persist and become deeper towards daybreak into early Friday morning. The lowest levels look too dry for precipitation to make it to the ground through about 7 AM. With dewpoints depressions already within 3 degrees in fog prone areas in east and towards, Cullman county, cannot rule out some patchy fog in those areas. At this point, though not expecting widespread dense fog. Held off on introducing chances pops after 4 AM due, mainly due to the very dry conditions in area soundings shown around 700 mb down to the boundary layer through 7 AM. However, after that period, precipitation could become more widespread than currently expected. .SHORT TERM...(Friday through Saturday) Issued at 140 PM CDT Thu Oct 8 2020 The initial showers associated with Hurricane Delta will begin to make their way into northern Alabama by Friday with the greatest coverage in showers in the late afternoon into the evening as a pseudo warm front lifts northward across Alabama. The lack of instability on Friday should limit thunder potential along this boundary. Model consensus this morning indicate a brief break in the rain after midnight until around sunrise. Saturday will be the day the Tennessee Valley sees the greatest impact from Delta as the tropical system moves northeastward across LA/AR/MS. The main impacts locally are widespread heavy rainfall between 1"-3", 25-30 mph wind gusts, and the potential for tornadoes. Given the speed of the system and the antecedent conditions, do not expect flooding to be a major concern. However, the threat is not zero as rain rates will be high, as is the case for most tropical systems, and a local flash flood risk could occur if training of storms occurs. The tornado threat is also quite conditional. Shear profiles are quite impressive in the low levels with 400-500 SRH in the 0-3km layer across northwest AL and slightly less farther east. However, there is a lack of instability, with models indicating between 300-500 j/kg of CAPE. If any breaks occur in the cloud cover, heating during the day may allow storms to overcome the capping inversion in place. Any strong storm to develop will likely begin to rotate given the shear profiles with the most favorable timeframe being Saturday afternoon during peak heating hours. .LONG TERM...(Sunday through Wednesday) Issued at 140 PM CDT Thu Oct 8 2020 Remnants of Tropical Cyclone Delta will linger over the region Sunday morning but impacts will be quickly waning as the system transitions to the NE. Bulk of any rainfall will shift east of I-65 moving toward the AL/GA border through the early Sunday evening. With the low filling in, not expecting any significant impacts on Sunday. With the TN Valley on the back end of the synoptic influence from Delta on Monday, warm and fairly moist air (for mid Oct) will linger over the area thanks to surface ridging parked over the eastern Gulf. This airmass will be short-lived as a weak, and nearly dry, cold front approaches the area from the west by early Tuesday. Expect very minimal forcing along this front with a lack of upper air support, so not expecting much in the way of rainfall. However, if this front can slow down and allow daytime heating and moisture to factor into surface based lifting, we could see a better chance of rain on Tuesday. Low confidence in that scenario. Temps Tuesday to peak in the upper 70s, 5-10 degrees less than Monday's high. Behind this aforementioned front, high pressures stacks over the area with dry air settling in. Highs will reach the mid 70s on Wednesday with dew point in the low 50s under mostly sunny skies. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1220 AM CDT Fri Oct 9 2020 VFR CIGS and virga continue over both terminals. Based on forecast and 00Z soundings, still keeping -SHRA and MVFR CIGS out of both terminals until after 15Z. Did include VCSH at KMSL due to scattered precipitation chances expected towards 12Z and after. Don't expect persistent MVFR CIGS or VSBYS until after 18Z, when precipitation should become more persistent. CIGS or VSBYS could drop a bit lower than currently in the forecast after 18Z, but kept on an optimistic side for now. Expect gusts to lessen after 10/00Z. However, MVFR CIGS/VSBYS will remain possible with -SHRA continuing. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...KTW SHORT TERM...GH LONG TERM...Barron AVIATION...KTW For more information please visit our website at weather.gov/huntsville.