####018006225#### FXUS64 KMRX 040032 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 832 PM EDT Fri May 3 2024 ...New UPDATE... .UPDATE... Issued at 819 PM EDT Fri May 3 2024 Showers will continue to linger this evening. A few storms possible in the Southern Valley and Cumberland Plateau. A lull in activity is likely overnight. Although, some showers will still be possible. Some patchy fog is possible in the early morning hours due to ground moisture but development will be somewhat limited due to cloud cover overnight. I went with Consshort guidance for POPs in the overnight period. NBM seems a bit overdone. CAMs are closer to Consshort with sporadic weak showers overnight. && .SHORT TERM... (This evening through Saturday) Issued at 240 PM EDT Fri May 3 2024 Key Message: A few instances of small hail, gusty winds, and locally heavy downpours are possible this afternoon with showers and thunderstorms. Discussion: Currently showers and thunderstorms are traversing across much of the southeastern United States being aided by a shortwave moving through the Tennessee Valley this afternoon. As of this writing there is predominantly just rain showers, but increasing instability means we'll likely see more thunderstorms moving through the southern Appalachians through the rest of the evening. Soundings and CAMs are still showing a few hundred (maybe up to near 1000) J/kg of MLCAPE the rest of this afternoon. Combine this with a fairly week lapse rate and very little shear, and the chances for widespread sever weather continue to look low. With that being said an individual thunderstorm could bring brief heavy rain, small hail, and gusty winds in areas that have destabilized this afternoon. With how slow these storms are currently moving and the possibilty of multiple storms over a small area, the biggest threat the rest of the afternoon/evening is likely to be flooding of low lying or poor drainage areas. As we head into the overnight hours we should see a lull in activity, and although the threat of rain does not go away, but the risk of lightning and strong storms really decreases as the shortwave exits the area and the atmosphere becomes more stable overnight. On Saturday we will likely see a similar story as today, with morning showers transitioning into afternoon thunderstorms with heavy rain, small hail, and gusty winds as the primary hazards in the strongest storms. Forecast soundings show a similar environment with weak to moderate CAPE and weak shear, so once again widespread severe weather looks unlikely. && .LONG TERM... (Saturday night through next Friday) Issued at 240 PM EDT Fri May 3 2024 Key Messages: 1. An unsettled pattern is expected through the extended period with daily scattered to numerous showers and storms. More organized convection is possible by Wednesday/Thursday of next week. 2. Temperatures will be generally above normal. Discussion: We start the period with a fairly weak upper level flow pattern over the region and a short wave moving through. Most model guidance suggest the short wave will exit by early Sunday, with short wave ridging building in. This may allow for less coverage of showers and thunderstorms Sunday afternoon, but it still looks like there will be enough moisture and instability for at least scattered convection. The upper level ridging looks to be short lived as another short wave aloft moves in Sunday night/Monday, along with more numerous showers and thunderstorms. Models suggest modest instability with MLCAPES likely around 100J/kg or less for both Sunday and Monday and shear will be on the weak side given the weaker flow. However some stronger storms with gusty downburst winds will be possible as well as locally heavy rainfall rates given the near 90th percentile PWATs (around 1.4 inches both days). The unsettled pattern will continue for the Tuesday through Friday time frame, although timing of individual short waves in the flow is uncertain. Ensembles do suggest a more dynamic pattern developing with the upper jet nosing in from the west/northwest then dipping south, and mean 850 mb flow will likely increase to 30+ kts and may exceed 40 kts at some point during the period. In addition, a cold front is forecast to be moving in from the northwest by the end of the period. There are still model differences and timing questions, but the data does indicate that by Wednesday we will see an environment with potentially better thermodynamics and deep-layer shear sufficient for more organized convection than in the earlier part of the extended period. This will bear watching going forward. The long term period will generally feature temperatures above seasonal normals, although precipitation timing/coverage may help to hold high temperatures down on some wetter days, and the cold front moving in Friday is expected to help hold temperatures Friday down closer to normal although timing that far out is of course still very uncertain. && .AVIATION... (00Z TAFS) Issued at 728 PM EDT Fri May 3 2024 Showers and storms will continue this evening mainly near CHA. A lull in activity is expected overnight but some showers will still be possible. Tomorrow morning showers will increase again and by afternoon activity will be more widespread. Isolated thunder will be possible tomorrow mainly in the afternoon. MVFR CIGs are expected late tonight through at least the morning hours. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 66 81 64 84 / 60 80 30 50 Knoxville McGhee Tyson Airport, TN 63 78 63 82 / 50 90 50 50 Oak Ridge, TN 63 78 62 82 / 60 90 40 50 Tri Cities Airport, TN 61 76 59 79 / 20 90 60 60 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM... AVIATION...McD ####018004457#### FXUS64 KJAN 040034 AFDJAN Area Forecast Discussion National Weather Service Jackson MS 734 PM CDT Fri May 3 2024 ...New AVIATION... .DISCUSSION... Issued at 245 PM CDT Fri May 3 2024 Tonight through Sunday night...Isolated to scattered showers and thunderstorms are occuring across much of the area this afternoon, and this will continue before ending from west to east early this evening. Skies may clear some overnight, and with good radiational cooling patchy areas of dense fog will be possible early on Saturday. An HWO graphic will be issued for this potential. Another short wave will move into the area Saturday afternoon and this will kick off another round of shower's and storms. With a little better lapse rate/instability on Saturday, a strong to possibly severe storm cannot be ruled out Saturday afternoon. Little will change on Sunday as moisture continues and yet another in a series of short waves move across the area. Drier air begins to move into the area Sunday night. Highs through the weekend will be in the 80s, with overnight lows in the mid 60s./15/ Monday into Friday...the overall forecast for next week remains similar. Focus will be well above normal/heat early into mid week, potential for severe storms mainly in the Thu-Fri periods, then followed by a marked cool down. The driver for the increasing warmth will be with a pattern shift to more of a ridge influence with the ridge axis over us Mon, then the ridge shifting eastward as we see a powerful system dive across the Rockies and Central Plains. We will be on the western periphery of the low level ridge/high and that will provide a decent S/SW lower level flow to bring in moisture and those well above normal lower level temps. Additionally, we will see capping in play which will keep rain/storm chances more in check. There's some 20-30% type PoPs for Mon-Wed, but this is more due to model variability and I expect this to lower some. The exception could be in the far N, where more proximity to the better lift could allow for better chances. As for severe weather potential...this is mainly looking like potential for a round or two sometime in the Thu/Fri periods. PoPs have come in higher which fits and will follow. Look for chances to continue to increase for a particular period as better timing starts to work itself out. Like yesterday and prev guidance, uncertainty is pretty decent on specifics and timing, which is often the case at day 6-7. However, the pattern and consistency for the needed ingredients (instability, steep lapse rates, moisture, shear, lift) continue to show up. I'll also add, later Wed night is a period to watch as well as there will likely be severe activity on-going to our NW/N which could migrate down into some of our northern area. Lastly, the ingredients I noted are all reaching very solid levels and fitting of a potentially upper end type event(s). Details will determine the type of severe, but at this time, confidence is on wind/hail. In the wake of this system, the trends are for a solid front/trough passage for the weekend which would bring much cooler conditions to the area. /CME/ && .AVIATION... (00Z TAFS) Issued at 734 PM CDT Fri May 3 2024 Other than some light SHRA lingering at GTR/MEI, expect clearing over the next hour. Expect a mixed bag of IFR-LIFR flight categories overnight, with worst flight categorical restrictions from low stratus & some dense fog across the area. Onset timing looks to be around 04/07-09Z before lifting to VFR around 07/14-16Z. Light southerly sfc winds will persist the next 24 hours, sustained up to 10mph & brief higher gusts. Some SHRA & iso TSRA are psbl Saturday aftn, but confidence is too low to introduce in the 00Z TAF cycle. /DC/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 64 86 66 83 / 10 40 30 50 Meridian 63 88 65 87 / 20 40 30 40 Vicksburg 64 86 67 83 / 10 40 30 50 Hattiesburg 65 88 66 87 / 0 30 10 30 Natchez 64 86 65 81 / 0 40 30 50 Greenville 66 84 67 80 / 10 40 40 60 Greenwood 65 84 67 83 / 10 40 40 70 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ 15/CME/DC