FXUS64 KHUN 200137 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 837 PM CDT Fri Apr 19 2024 ...New NEAR TERM... .NEAR TERM... (Tonight) Issued at 837 PM CDT Fri Apr 19 2024 The cold front has now moved SE of the central TN Valley this Fri evening, with lingering convection tapering off to the south over central AL. Weak CAA is now filtering into the area out of the north, with dew pts falling into the 50s across parts of mid TN. These lower dew pts will continue to drift southward overnight, allowing lows into early Sat to fall mainly into the lower/mid 50s. Zonal flow is also in place over much of the region, with a subtle embedded disturbance moving eastward into the southern Plains. While the bulk of this upper wave should remain west of the area into early Sat, weak synoptic lift developing across parts of the region may allow for a few very light showers, predom north of the TN River, prior to daybreak. && .SHORT TERM... (Saturday through Monday night) Issued at 250 PM CDT Fri Apr 19 2024 Nocturnal convection developing across the southern Plains late tonight (in the regime discussed above) may organize into one or two broader clusters during the day on Saturday that would subsequently track east-southeastward into MS/AL. Although the risk for thunder with this activity should remain confined to locations along and immediately north of the stalled frontal boundary to our south, we will maintain a very low probability for a few lightning strikes tomorrow afternoon (mainly south of the TN River) as the northern portions of the storm clusters begin to spread light rain eastward into our forecast area. Temperatures will struggle to rise 10-15 degrees above morning lows due to an abundance of cloud cover and northerly winds of 10-15 MPH (gusting up to 20 MPH at times), and we have indicated highs in the l-m 60s. This precipitation regime will persist into the evening hours on Saturday, as another large mass of rain and embedded thunderstorms (associated with a slightly stronger wave in the subtropical jet) spreads northeastward from central TX. Models suggest that the initiating mid-level disturbance may intensify a bit as it tracks northeastward across the Lower MS Valley early Sunday morning, with synoptic scale lift expected to be maximized across our forecast area this period. However, the layer of cool/dry air in the low-levels will be deepening with time, presenting some concern about the northward extent of rainfall with the second wave (Sunday morning). Although any rain will end in our southeastern zones early Sunday afternoon, clouds will be slow to clear the region and highs will struggle to make it out of the u50s-l60s. A weakening surface ridge of high pressure will shift eastward into the Ozarks by early Monday morning, before crossing the TN Valley Monday and building further northeastward off the Mid- Atlantic coast Monday night. This, along with a low-amplitude ridge aloft, will support dry conditions and clear skies, with some patchy frost possible early Monday morning (especially across our southern Middle TN zones) when dewpoints will be in the l-m 30s. Highs will rebound into the m-u 60s on Monday afternoon. && .LONG TERM... (Tuesday through Thursday) Issued at 233 AM CDT Fri Apr 19 2024 Afternoon Update: Based on the 12Z suite of global models, all thoughts mentioned in the extended discussion (below) remain valid this afternoon. For how volatile late-April can be for our area, next week looks pretty pleasant, relatively speaking. Surface high pressure will keep higher rain chances at bay and high temperatures in the mid-70s. A few things to monitor will be a shortwave trough digging into the Great Lakes region with an attendant surface low that may drag a cold front into the South. For now, low rain chances (20-30%) are in the forecast for late Tuesday into Wednesday. The greatest potential for rain with this system will stay farther north, but that could change if the trough digs farther south. The second feature to watch is a longwave trough that will set up over the Western US late next week. This may lead to ridging and warmer temperatures over the Southeast in addition to sending several impulses through the area, which would lead to multiple periods of showers and thunderstorms next weekend. && .AVIATION... (00Z TAFS) Issued at 555 PM CDT Fri Apr 19 2024 MVFR conditions are forecast through the TAF period at both KMSL and KHSV as low clouds continue to move into the TN Valley. After 19Z Saturday, a PROB30 group has been added to account for low chances of light showers leading to decreased visibilities and continued lowered ceilings. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...09 SHORT TERM....70 LONG TERM....30 AVIATION...HC