####018005937#### FXUS64 KSHV 040721 AFDSHV Area Forecast Discussion National Weather Service Shreveport LA 221 AM CDT Sat May 4 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (Saturday through Sunday) Issued at 122 AM CDT Sat May 4 2024 Pretty quiet this morning for a change with plentiful high cloud cover present from anvil blowoff from storms early Friday evening across Central Texas. The cirrus is thin enough such that we are seeing some radiational fog across our eastern half. This should mix out by mid morning and while patchy dense fog will be possible, it does not appear to be widespread enough to warrant any advisory this morning. A wedge of drier air has settled in across the I-20 Corridor in the form of PWATS near or slightly below one inch from NE TX into N LA. While this moisture will recover somewhat by afternoon, it should result in less precip coverage areawide and thus have backed off NBM pops slightly, more in the range of slight chance/chance variety tied to daytime heating. Whatever storm coverage we see this afternoon should dissipate quickly with the loss of daytime heating. We then await a much stronger disturbance poised to impact our region late tonight and through the day Sunday. This disturbance, embedded in southwesterly flow aloft, will eject out of the Tx Hill Country this evening, moving rapidly towards the Piney Woods of NE TX into the Middle Red River Valley of SE OK by 12z Sun. Widespread showers and thunderstorms will accompany this disturbance overnight with a pretty tight pop gradient after midnight, ranging from categorical pops across NE TX, SE OK and extreme SW AR to slight chance pops across our far eastern zones. Marginal Threat of Severe Thunderstorms will exist across our northwest half after midnight as the decaying MCS makes good progress into our region prior to 12z Sun. Expanded categorical pops eastward across all but our extreme eastern zones Sun Morning as the decaying system continues moving east and with the atmosphere likely worked over Sunday Morning, backed pops back to high chance variety across most areas by Sunday Afternoon. A Slight chance of Excessive, Heavy Rainfall is outlooked across our western half on Sunday and this appears to be mostly for Sunday Morning with rainfall amounts near one to two inches possible through the day Sunday. We should be able to take this additional rainfall without too much in the way of difficulties other than small additional rises on area waterways. Therefore, Flood Watches do not appear to be necessary with the onset of this next storm system tonight through Sunday. 13 && .LONG TERM... (Sunday Night through Saturday) Issued at 122 AM CDT Sat May 4 2024 Trough ejects out to our north and east Sunday Night with weak upper ridging in its wake. Another upper level trough will rapidly eject out of the Intermountain West and into the Southern/Central Plains on Monday. While most of our region will be removed from the impacts of this next trough, forcing will be slightly enhanced across our northern zones so kept with NBM's handling of mostly chance pops across our northern half with slight chance pops south for Monday. Pretty uneventful day planned for Tue other than slight chance pops near and northwest of the I-30 Corridor, then southwest flow aloft begins to become enhanced as we await disturbances embedded in this flow to impact our region Wed into Thu. Latest operational runs of the GFS and ECMWF are in pretty good agreement with a frontal intrusion into our region sometime Wed Night into Thu and this will result in our next chance for strong to severe thunderstorms, not to mention periods of locally heavy rainfall once again. Progs show this frontal intrusion pushing completely through our region Thu Night through Friday with drier and somewhat milder conditions for Friday and into the upcoming weekend and this would be a break from the parade of systems and rainfall our region has seen recently. In advance of this cold front, our region will likely experience some of the hottest temperatures we've seen this Spring with afternoon highs Tue and Wed ranging from the middle and upper 80s to the lower 90s across our entire region. With high dewpoints in place, heat indices both afternoons could push 100 degrees in some locations. 13 && .AVIATION... (06Z TAFS) Issued at 1244 AM CDT Sat May 4 2024 Terminal winds have gone just about calm airspace wide this evening and given the close T/Td relations, some BR has started to develop, reducing VSBY at select terminals. That being said, cirrus will continue to filter across the airspace over the next several hours, which may limit the extent of the BR influence VSBY impact. Over the next few hours though, given limited cloud coverage across the central and eastern airspace terminals, VSBY will likely continue to fall through early Saturday morning. Just after 12z, VSBY should recover, with much of the airspace under dense OVC with some gradual BKN returning by the evening. While this package does not discuss the arrival of SHRA/TSRA, the 12z period will begin to introduce this. RK && .PRELIMINARY POINT TEMPS/POPS... SHV 86 69 80 66 / 40 40 100 20 MLU 85 66 80 66 / 40 20 70 20 DEQ 83 64 74 64 / 50 100 100 20 TXK 84 67 77 65 / 50 80 100 20 ELD 85 64 77 64 / 40 30 90 20 TYR 83 68 78 67 / 50 100 100 20 GGG 84 67 78 65 / 50 100 100 20 LFK 84 68 79 65 / 40 90 100 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ SHORT TERM...13 LONG TERM....13 AVIATION...53 ####018005324#### FXUS64 KMRX 040721 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 321 AM EDT Sat May 4 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (Today and tonight) Issued at 313 AM EDT Sat May 4 2024 Key Messages: 1. Numerous showers and thunderstorms expected this afternoon, mainly across eastern mountain and foothill areas near the TN/NC line. 2. Drier tonight with more isolated convection due to shortwave ridging, but this is expected to be short lived as another trough moves east across the Lower Mississippi Valley. Discussion: Weak troughing across the region will continue to result in southerly flow and periods of showers and thunderstorms. The most widespread coverage is expected during the afternoon hours when instability is at its peak. The greatest coverage is also expected east of the trough axis which will place highest PoPs near our far eastern counties across the mountains near the TN/NC state line through southwest Virginia. Some locally heavy rain rates will be possible with PW values near the 90th percentile, but overall, the flash flood risk is very low. Shortwave ridging arrives tonight as the trough axis shifts east and another shortwave troughing moves into the Lower Mississippi Valley. Temperatures remain near normal today and tonight. && .LONG TERM... (Sunday through Saturday) Issued at 313 AM EDT Sat May 4 2024 Key Messages: 1. Scattered to numerous showers and storms are expected each day through at least Thursday with more organized convection possible Wednesday to Thursday. 2. Temperatures will be generally above normal through Thursday. Sunday through Tuesday At the start of the period, fairly weak flow will be in place aloft with a shortwave ejecting out of the Southern Plains. Warm conditions and abundant moisture will be present across much of the southeast. During the day, the shortwave will continue to progress eastward with downstream ridging allowing for warmer conditions across the region. Surface heating will lead to development of showers and storms, especially across the higher elevations in the afternoon hours. The overall environment will consist of minimal shear and fairly low-end instability, i.e. MLCAPE of near or above 500 J/kg. Sunday night into Monday morning, the aforementioned shortwave will approach the area from the west and begin to flatten, which will be sufficient for more widespread showers and storms. Based on the timing, instability will remain fairly limited as surface heating will be capped by convection and cloud cover early in the day. On Tuesday, ridging will return and will lead to warmer conditions once again. A strengthening upper jet will be noted to the northwest and will be slowly progressing eastward. This will help to increase the flow throughout the layer and promote a more veered wind profile. Current data suggests MLCAPE at or above 1,000 J/kg with more notable deep-layer shear, which would support better organization to convection than in previous days. Wednesday through Friday By Wednesday, the aforementioned northern jet will remain across the same area with a southern jet strengthening to in excess of 100 kts. A surface frontal boundary will also be located across the Plains. This will provide a broader divergent pattern aloft and 850mb flow possibly reaching 40 kts by the evening and into Thursday while the frontal boundary approaches from the northwest. Models are suggesting a potential MCS moving into the area from late Wednesday into Thursday morning, which would be supported by the overall pattern. In any case, convection during this timeframe would likely be even more organized than on Tuesday. This timeframe will definitely be something to watch as confidence increases, but low probability HWO wording will be maintained for to encompass this event and repeated convection earlier in the period. By Friday, the front is likely to move through the area, which, combined with height falls, will promote cooler conditions. && .AVIATION... (06Z TAFS) Issued at 129 AM EDT Sat May 4 2024 Scattered showers and thunderstorms continue through the forecast period which will impact aviation at all sites. CHA will see some impacts early this morning with convection being more isolated during the morning and mid-morning hours. This afternoon, thunderstorm activity will become more widespread with more impacts expected in the vicinity of all terminals. Some areas of low clouds and fog are possible this morning, mainly in the vicinity of TYS and TRI. Winds remain generally light. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 80 65 85 66 / 70 20 40 50 Knoxville McGhee Tyson Airport, TN 77 62 82 64 / 60 40 50 40 Oak Ridge, TN 78 62 83 64 / 70 40 50 40 Tri Cities Airport, TN 75 60 79 60 / 90 40 60 40 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...JB LONG TERM....BW AVIATION...JB ####018009892#### FXUS62 KGSP 040722 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 322 AM EDT Sat May 4 2024 .SYNOPSIS... A front will stall over the region through the weekend resulting in periodic showers and thunderstorms. The best chance for widespread showers and thunderstorms can be expected today into tonight, with only scattered activity expected on Sunday. A general summertime pattern sets up early next week, which will keep scattered thunderstorm chances around each afternoon. Highs will trend well above normal by Tuesday, remaining well above normal through at least Thursday. && .NEAR TERM /THROUGH TONIGHT/... As of 300 am EDT Saturday: Isolated/scattered convection is ongoing within general low level confluence zone/coincident deep moisture plume within broad area of modest height falls. Convective coverage is expected to increase steadily through the morning as a short wave trough steadily approaches our area from the Deep South. Eventually, categorical coverage of convection is expected from around late morning through the afternoon. Precipitable water values will remain very high...generally in the 90th-99th percentile of the daily climatology for our area. A weak backdoor cold front is expected to nudge into the CWA from the northeast later this morning, with the leading edge likely settling in the vicinity of the NC/SC border by this afternoon. This will provide an additional source of lift for convective initiation, and could be the focus for locally heavy/ perhaps isolated excessive rainfall this afternoon. Deep S/SW flow will also pose the potential for training cells within persistent confluent zone. Heavy rain has been very spotty since Fri afternoon, so dry antecedent conditions remain the norm across the forecast area, but higher coverage of showers and storms combined with the above factors will result in a ramping up of the excessive rainfall threat today. Extensive cloud cover (max temps actually a little cooler than climo) and poor mid-level lapse rates will result in rather weak buoyancy through today, while shear parameters will remain weak, so the conditional probability of severe storms remains close to zero. As the short wave trough finally drifts over the forecast area tonight, the zone of low level confluence and moisture plume will begin to shunt east of the area. However, this trend will be rather slowly evolving, so convective chances will remain elevated through at least the evening, before slowly winding down overnight. The threat for locally excessive rainfall threat will persist through at least the evening. Min temps will again be well above normal. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... As of 230 AM EDT Saturday: A stationary front will be draped from the Ohio Valley to the Southern Plains Sunday into Monday, remaining well west and north of the western Carolinas. This will allow for SW'ly flow at 850 mb keeping an influx of rich gulf moisture in place across the region. Convective chances look to be much lower on Sunday compared to Saturday thanks to a weak upper trough gradually pushing east of the western Carolinas throughout the day. However, isolated to scattered showers and thunderstorms are still expected to develop throughout Sunday per the 00Z CAMs. Thus, have likely PoPs in place across the northern zones, with chance PoPs across the southern zones. Storm movement will continue to be slow on Sunday with only about 10-15 kts of shear in place so locally heavy rainfall will be possible, especially for areas that received rain on Saturday. The majority of guidance shows SBCAPE values ranging from ~800-1500 J/kg during peak heating Sunday afternoon. Model soundings from both the NAM and GFS show an inverted-V and mid-level dry air in place Sunday afternoon. Thus, an isolated severe storm or two cannot be entirely ruled out, with the main potential impact being damaging wind gusts. Shower and thunderstorm chances will show a slight uptick on Monday as upper shortwaves track overhead the western Carolinas. Went with categorical PoPs across the western third of the forecast area on Monday, with likely PoPs elsewhere. The strong to severe storm potential and locally heavy rainfall threat return again on Monday thanks to continued weak shear and 800- 1500 J/kg of SBCAPE in place. Highs should end up a few degrees above climo through the period, with lows around 10-13 degrees above climo. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 200 AM EDT Saturday: Weak upper ridging builds into the Carolinas on Tuesday while an upper shortwave tracks overhead the forecast area. This will act to keep shower and thunderstorm chances around across most of the forecast area. Have the highest PoPs (likely) confined to the NC/TN border, with chance PoPs elsewhere (the exception being the far southern tier of the CWA where there are no mentionable PoPs). With shear values expected to range from 25-35 kts and SBCAPE values around 1500 J/kg on Tuesday afternoon, isolated strong to severe storms seem plausible. Tuesday night into Wednesday weak upper ridging will continue building across Carolinas. This should generally lead to lower convective chances compared to Tuesday. Thus, capped PoPs to chance across the western two-thirds of the forecast area. However, since cloud cover is currently expected to be lower on Wednesday, global models depict SBCAPE ranging from 1500-2500 J/kg during peak heating, with shear still generally ranging from 25-35 kts. Thus, diurnal strong to severe storms will be possible again on Wednesday. At the sfc, a cold front will slowly progress eastward out of the central US but will remain well west of the Carolinas. This will lead to W/SW'ly 850 mb flow in place Tuesday into Wednesday, allowing temps will climb into the mid to upper 80s east of the mts and across the mtn valleys each afternoon. A few locations along I-77 in the southern NC Piedmont may even see highs reach 90 degrees on Wednesday. Thus, highs should end up around 6-12 degrees above climo. Lows Tuesday night and Wednesday night should end up around 12-15 degrees above climo thanks to some lingering cloud cover and SW'ly sfc winds. The aforementioned cold front will continue trekking eastward Thursday into Friday leading to better shower and thunderstorm chances for the western Carolinas as well as the potential for locally heavy rainfall (especially for areas that received rainfall earlier in the week). Convection will be in place well ahead of the front Thursday into Friday so have chance PoPs painted across the entire area. The only exception is the NC mtns where likely PoPs are in place for Thursday. The actual FROPA itself should track across the western Carolinas Friday afternoon into early Friday evening. The front will allow shear values to increase slightly, ranging from 35-45 kts. Guidance shows SBCAPE values ranging from ~1500-2000 J/kg on Thursday afternoon so the potential for strong to severe storms will return once again. Depending on how fast activity pushes south and east on Friday, the potential for strong to severe storms may return again Friday afternoon (mainly along and east of I-85). Temps will climb back into the mid to upper 80s Thursday afternoon across the mtn valleys and east of the mtns. A few locations along I-77 in the southern NC Piedmont may once again see highs reach 90 degrees. Slightly cooler temps can be expected on Friday behind the cold front, with highs only climbing into the lower to mid 80s east of the mtns. Lows Thursday night will remain ~12-14 degrees above climo, becoming ~5 degrees above climo Friday night behind the cold front. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... At KCLT and elsewhere: Very messy aviation forecast this period, as unusually high moisture levels for the time of year combined with weak lift and instability will yield periods of convection and cig/ visby restrictions through much of the period. Isolated convection, including some TSRA is ongoing across the area early this morning, warranting VCTS at KAND/KGMU. The convective potential as well as the likelihood of lowering cigs is expected to steadily increase toward sunrise, warranting tempos for SHRA and IFR/MVFR conditions. Can't rule out a TSRA during this time frame, but believe the potential should be higher later in the morning into the afternoon. Cigs are forecast to settle to IFR by late morning, with conditions expected to be slow to improve into the afternoon. The potential for TSRA warrants a Prob30 for such at all sites from late morning through much of the afternoon. This is accompanied by categorical SHRA and MVFR visby. The convective potential is expected to steadily decrease toward the latter few hours of the period. However, at least VCSH is warranted Sat evening into the early part of Sunday. Any modest improvement in cigs/visby during the afternoon will be reversed by late evening. Outlook: Enhanced moisture will combine with a weak/stalled front through early next week, resulting in a period of active/mainly diurnal convective weather each day. There will also be the potential for restrictions associated with widespread fog and/or low clouds each morning. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...AR NEAR TERM...JDL SHORT TERM...AR LONG TERM...AR AVIATION...JDL ####018005513#### FXUS61 KILN 040724 AFDILN AREA FORECAST DISCUSSION National Weather Service Wilmington OH 324 AM EDT Sat May 4 2024 .SYNOPSIS... A warm and moist airmass will remain in place across the region into the middle part of next week, leading to occasional periods of showers and thunderstorms. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... Mid level short wave energy will lift northeast across the mid Ohio Valley through the day. Forcing isn't terribly great, but in a moist airmass, this has been enough to maintain scattered shower activity across southeast portions of our area so far this morning. Flow aloft is very light, so this activity will very slowly pivot up across mainly eastern portions of our area through mid morning. As we head through late morning and into this afternoon, some weak instability will develop as afternoon highs push into the mid to possibly upper 70s. This will allow for a continuation of occasional showers along with a chance for thunderstorms. Given the light flow and general lack of deeper shear, the overall severe threat will be low. However, with PWs up around 1.5 inches and the slow storm movement, some heavier downpours will be possible today. && .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/... As we lose the daytime heating and the mid level short wave moves off to our northeast, expect an overall decreasing trend in pcpn this evening and into the overnight hours. Lows tonight will mostly be in the lower 60s. Another mid level short wave will move east across the Great Lakes region on Sunday. An associated weak surface wave will move across the southern Great Lakes while a trailing weak cold front moves east across our area during the day on Sunday. This will lead to additional chances for showers and thunderstorms, especially across eastern portions of our fa Sunday afternoon. With a little better deep layer shear, a few strong to severe storms may be possible across our eastern areas Sunday afternoon. The main severe threat would be damaging winds. Highs on Sunday will range from the mid 70s northwest to around 80 degrees in our southeast. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... A strong surface high over MI will push drier air into the northern Ohio Valley behind a departing cold front. A s/w undercutting a mean H5 ridge will move east and into the Ohio Valley on Monday. The earlier cold front will have draped w-e through southern CWA Monday, and then begin to lift northeastward as a warm front overnight. The region will be warm-sectored on Tuesday with scattered showers and thunderstorms expected with daytime heating. Earlier showers with embedded thunderstorms on Monday/overnight look to be triggered by the surface front. Tuesday night, warm sector showers will scatter out as a convective line works in from the west ahead of a H5 s/w and trailing the exiting upper ridge. This looks to be behaving as a cold front, but the only front mildly shown in guidance is a shift from the highest moisture on Tuesday to slightly drier air (back to what has been seen) overnight. A brief drying on Wednesday will change after daytime as strong southwest flow brings a continued feed of deep moisture that will be wrung out overnight. This will be the most prominent rainfall period in the extended forecast. While some showers may linger into Thursday/Thursday evening ahead of a H5 trough, the region should be fairly worked-over enough to where upper level lift will not overcome an expected stable airmass behind Wed night's rain. Low chance pops continue through the forecast but the overall end of the period beginning Thursday evening looks to be dry and cooler. Cooler to the extent that from Thursday night through Saturday it will be near seasonal normals. Beginning with a brief cooling on Monday, temperatures will warm through Wednesday and cool through the remainder of the period. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... Isolated to scattered showers will continue to lift slowly northeast and perhaps become a bit more numerous through the morning hours as mid level short wave energy lifts up across the Ohio Valley. Cigs are quite variable early this morning, ranging from LIFR in spots to MVFR and VFR across much of the rest of the area. As the lower levels continue to moisten up, think we will see an overall downward trend in cigs as we progress through the pre dawn hours so will generally allow for prevailing MVFR with some tempo IFR conditions. Areas of MVFR to locally IFR vsbys restrictions will also be possible through mid morning. As we head through late morning and into this afternoon, prevailing VFR conditions will return. However, as we destabilize through the day, periods of showers and embedded thunderstorms can be at time this afternoon. This activity should begin to taper off from the west late in the day and into this evening. OUTLOOK...Thunderstorms are possible at times each day from Sunday through Wednesday. MVFR conditions are possible Sunday morning and Monday morning. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...JGL NEAR TERM...JGL SHORT TERM...JGL LONG TERM...Franks AVIATION...JGL