FXUS64 KMRX 291359 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 959 AM EDT Fri Mar 29 2024 ...New UPDATE... .UPDATE... Issued at 955 AM EDT Fri Mar 29 2024 Updated forecast with end of Frost Advisory this morning. Overall forecast has not changed. Did update hourly winds, temperatures and dew points to reflect current trends. Also raised high temperatures a degree or 2 across parts of southwest North Carolina and 1 degree in southwest Virginia, Chattanooga and Knoxville. This only made a very small change in minimum relative humidity values. Expect rapid warm up of temperatures regionwide today and gusty westerly winds across southwest Virginia and northeast Tennessee this afternoon. && .SHORT TERM... (Today and tonight) Issued at 321 AM EDT Fri Mar 29 2024 Key Messages: 1. Low afternoon humidity coupled with breezy conditions again today. Mainly in the north though. Discussion: About the only forecast concern we have going in the short term will be another of low afternoon humidity values that will coincide with some gusty winds. This will be mainly in the northern third or so of the forecast area. An upper trough will continue to pull away to the east today, with surface high pressure building in behind it. While overall moisture levels will be on the increase, as evident in an upward trend in forecast PWAT values across the CWA today, the low levels will still be quite dry. Forecast soundings show PWATs still below 1" over the northern parts of the forecast area this afternoon especially. Expect to see resulting afternoon RH values drop into the 25-30 percent range for a majority of the forecast area. In addition to the dry air, the upper ridge will be positioned to our west today, leaving us beneath WNW upper level and H85 flow through the day. While the H85 winds will be decreasing as the stronger flow pulls away to the east, we will likely still keep +20kt of H85 winds for much of the area north of the I-40 corridor today. Coupled with mixing heights extending up to around 8,000 ft, this should promote gusts over 20 mph for that same region. I wouldn't be surprised if areas near/north of the VA and TN line saw some gusts over 30 mph before early afternoon as forecast H85 winds will likely still be in the 30-40kt range during that time and mixing may very well be deep enough to tap into some of that by that time. Will likely go with a fire danger statement to highlight the fire weather concerns with today's dry and breezy conditions. Otherwise, not much going on in the short term as we'll be dry and mostly clear. && .LONG TERM... (Saturday through Thursday) Issued at 321 AM EDT Fri Mar 29 2024 Key Messages: 1. Much warmer this weekend. Chances of rain mainly across southwest Virginia Saturday and Sunday. 2. An upper level system will bring unsettled weather and warmer temperatures for next week, especially thunderstorm potential on Tuesday. 3. Cooler temperatures behind a cold front Wednesday and Thursday of next week. Higher elevation rain/snow mix possible. Discussion: We start the forecast period with quasizonal flow aloft and a weak frontal system to the north, that will bring increased chances for showers for southwest Virginia and possibly just across the border into Tennessee over the weekend. Otherwise, Easter weekend expected to be a warm one with temperatures 10+ degrees above normal for the end of March. Expect highs approaching 80 across the middle and southern valley Sunday afternoon. High pressure positioned over the SE paired with southwesterly return flow, will allow temperatures to remain warm into the first part of next week, as well as increase the humidity. Dew points will be nearing 60 degrees Monday and Tuesday. The system to watch will be beginning on Tuesday, as a cold front is forecast to cross the area, sending much cooler temperatures in its wake Wednesday and the rest of the period. A low will develop near the lee of the Rockies early in the week, before deepening and moving towards the eastern Great Lakes. Models show this system deepening further after the front passes our area. This will be one to monitor as it is subject to change and the SPC yesterday morning highlighted a part of our forecast area under a 15% chance of severe weather on Day 6 Tuesday (now considered Day 5). Timing of the frontal passage will affect just how much severe weather our area could potentially see. Following the frontal passage late Tuesday into Wednesday, winds will shift to the northwest sending a much cooler airmass into the area. NW flow induced showers may linger into Thursday. There is a possibility of mixed precip across higher terrain once cold air settles in. Coldest morning will be Thursday, which could pose a frost and freeze threat. We end the forecast period with surface high pressure and ridging aloft moving in from the west, thus dry weather and rebounding temperatures. && .AVIATION... (12Z TAFS) Issued at 718 AM EDT Fri Mar 29 2024 Only aviation concern for the 12z TAF package remains the gusty winds at KTRI today. Expect those to begin around 15z as we see a fairly quick rise in the mixed layer this morning. Initial gusts should be in the 18-20kt range, with peak values in the low to mid 20kt range by this afternoon. Elsewhere, believe that winds will remain below 10kt, with KCHA being light and variable through the period. Only clouds around will be some increasing cirrus late in the period. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 72 49 76 53 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 69 47 74 55 / 0 0 0 10 Oak Ridge, TN 70 45 76 53 / 0 0 0 10 Tri Cities Airport, TN 66 42 71 52 / 0 0 0 20 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...TD LONG TERM....KS AVIATION...CD