947 FXUS64 KHUN 102304 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 504 PM CST Fri Feb 10 2023 ...New AVIATION... .NEAR TERM... (Tonight) Issued at 153 PM CST Fri Feb 10 2023 A low pressure system along the OK/TX border will drop south and east tonight towards the Gulf Coast. The only impact to the local forecast area is an increase in mid to high level cloud cover. Otherwise, a tranquil evening is in store. Overnight lows drop to near their climatological normals in the mid to upper 30s. The only other thing of note tonight is winds will stay elevated around 10 to 15 mph as the low pressure system gets closer to the area. && .SHORT TERM... (Saturday through Monday) Issued at 153 PM CST Fri Feb 10 2023 The aformentioned low takes a turn to the north and east tomorrow. While the bulk of the moisture will remain to our south, strong moisture advection along the backside of the low results in showers spreading into Northern Alabama and Southern Middle Tennessee. Rain will move from south to north starting Sat. afternoon and continuing through the overnight hours. In total, 0.5-1 inch of rain is expected with the higher amounts further east. Of greater interest is the potential for the rain to transition to snow late Saturday night into early Sunday morning. As the low deepens, temperatures are expected to drop to near freezing after midnight. The biggest uncertainty in this forecast is how much cold air we get before the precip ends. Based on model soundings, it will either be rain or snow as temperatures aloft are below freezing. Current opinion is that blended guidance continues to be a bit warm, especially given the likely dynamical forcing from a strengthening low that will help bring colder air down to the surface. However, the current forecast still keeps temperatures right around 32 degrees for areas east of I-65 and north of the Tennessee River and slightly warmer elsewhere. Therefore, the latest forecast shows snow accumulation (<1 inch) only in the higher elevations in northeast Alabama and southern middle Tennessee. This is still a low confidence forecast as a degree or two change may result in a drastic change in snow amounts. The good news is that impacts from any snow that does fall will be minimal. Temperatures during the day Sunday rise back into the 50s. Although it may feel a bit cooler with winds gusting 20-25 mph behind the previous system. By Monday, upper level ridging across the central CONUS shifts eastward towards the Southeast. The overall upper flow pattern shifts to WSW resulting in WAA. Highs on Monday are forecast to reach into the lower 60s. && .LONG TERM... (Tuesday through Friday) Issued at 153 PM CST Fri Feb 10 2023 An active long term forecast period is expected as two disturbances will traverse the local forecast area. The first of these systems moves through on Tuesday night as a wave riding along the base of a trough to our west ejects northeastward towards the Tennessee Valley. This will be the least impactful system in the long term period as the only impact will be locally heavy rainfall. A more potent system is forecast to arrive late Wednesday into Thursday. Another trough develops to our west and a low pressure system is expected to form and lift north and east across the Plains and into the Great Lakes region. Further south, a warm front lifts northward across Alabama Wednesday bringing a round of showers and thunderstorms. With the warm front to our north, temperatures soar into the upper 60s to lower 70s during the afternoon on Wednesday. Strong moisture advection helps raise surface dewpoints into the lower 60s on Thursday before a cold front sweeps through the area bringing the potential for a stronger round of thunderstorms. This system has the ingredients for a high shear low CAPE QLCS. As a result, SPC has outlooked the Tennessee Valley in a day 7 (Thursday) risk area. At this time, it is difficult to dive into the details given it is still a week out. But this is something we need to watch and will hone in on over the next few days. The post frontal airmass arrives Thursday night into Friday bring a cool and dry end to the work week. Highs on Friday will only reach the mid 40s with overnight lows in the 20s. A drastic change from just a few days prior. && .AVIATION... (00Z TAFS) Issued at 504 PM CST Fri Feb 10 2023 VFR flight weather conditions will last through most if not the entire period. However, light rain and lowering ceilings will develop by 20-22Z/11 which will approach MVFR (~025-030agl). Thus, future updates may need to include this, and likely will beyond 24 hours as the rain spreads northward. The other weather of note will be increasing north-northeast winds after 14Z, with gusts around 20kt expected. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...GH SHORT TERM....GH LONG TERM....GH AVIATION...17