####018006116#### FXUS62 KILM 160736 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 336 AM EDT Fri May 16 2025 .SYNOPSIS... Above normal temperatures, with near record highs possible, are expected through Sat. A weak cold front accompanied with isolated convection at best will track across to south of the area late Saturday night. Dry weather and near normal temps to carry on thru Wed, however by the mid-week period of next week, the next storm system may affect the FA with unsettled weather. && .NEAR TERM /THROUGH TONIGHT/... Somewhat deep west to northwest (early) flow will remain in place across the area today. Near record to record highs are expected for afternoon highs with only Florence (95 forecast...record 93) at least at this point explicitly in record territory. The next candidate to break a record is Lumberton (94 forecast...record 96) as the coastal areas may see a race between the resultant sea breeze which will be decent as the westerly flow isn't the strongest I have seen and the warmth. For tonight into Saturday morning expect warm and dry conditions to continue with lows in the lower to perhaps only middle 70s. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Breezy conditions slated for Sat as a sfc trof across the central Carolinas gets displaced by a sfc cold front driving ESE. This aided by an upper low over the Great Lakes and associated upper trof axis extending south of it, all pushing to the East. By Sun daybreak the upper low will be over the NE States with its trof axis extending south across the area. This will help drive a cold front across the FA likely sat aftn and night. It'll likely stall just south of the FA as it becomes aligned parallel with the flow aloft. Models do scour a good chunk of moisture after crossing the Appalachians leaving mainly clouds associated with its passage. Eventhough POPS will be 20% at best, the isolated convection that does develop will immediately have the potential to go severe given the avbl instability and shear. Max temps in the 90s Sat will have the potential to reach record levels across a few of our climatic sites. Later Sun thru Sun night, building upper ridge axis along the MIssissippi River Valley and the upper trof axis off the SE STates Coast will result in NW flow aloft. Could see an embedded vort within this NW flow push across the FA Sun aftn resulting in a possibility of raising POPs across the FA. Not entirely bought on this given previous model runs kept it south of the FA. Sun max temps a few degrees cooler than Sat maxes. && .LONG TERM /MONDAY THROUGH THURSDAY/... The FA will be more under the influence of the upper ridging across the Central U.S. with the upper trof axis remaining well offshore from the FA. NW flow aloft will continue Mon thru Tue with yet another embedded vort s/w trof that possibly drops across the FA within NW flow. Once again, confidence remains low given the back and forth progged movement/strength of this feature. Nevertheless, a reflection of it will be the cloudiness being invoked into the fcst. Late Tue into Wed the upper ridge axis pushes off the SE States Coast followed by a sharpening/amplifying upper trof across the Eastern 1/3rd of the U.S. This has been advertised by models, however the remain wishy-washy with any Pop threat. At this point will cap Pops in the low to possibly modest chance during the mid-week period. Temps this period will start above normal then drop back to near or below normal depending how much of that Canadian airmass infiltrates the FA. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... VFR conditions expected through the forecast period, as a building mid-level ridge keeps convection suppressed. Extended Outlook...Mainly VFR conditions are expected through the period. && .MARINE... Through Tonight...Southwest winds which have probably reached their peak just north of 15 knots will continue today in a range of 10-15 knots. Speeds will diminish slightly tonight before the low level jetting once again sees an uptick. Significant seas will see a narrow range of 3-4 feet today dropping in a subtle nature to 2-4 feet later tonight into Saturday AM. Saturday through Tuesday Night...Tightened sfc pg will be ongoing to start Sat off. Inland sfc trof will be replaced by a SE-ward dropping cold front Sat aftn. This front should push off the mainland and thru the local waters mainly Sat night. Could see tstorm activity spring up after pushing off the coasts, as it interacts with the Gulf Stream. Winds Sat into Sat night will flirt with SCA 25+ kt wind gusts. The sfc pg will relax after FROPA and remain-so thru Mon night, resulting in reduced wind speeds to aob 10 kt. Wind directions will be the problem child during this period. By Tue, some organization of the pressure field as well as some tightening of the gradient. Seas start at 2-4 ft with 5 footers possible. Mainly looking at wind driven waves at 5 or less second periods becoming dominant with an underlying small but identifiable SE swell at 8+ second periods. && .CLIMATE... High temperature records may be challenged Friday and Saturday as anomalously warm air overspreads the region ahead of a cold front. Record highs for our four climate sites are as follows: For Friday, May 16th... Wilmington, NC: 94F (1915) Lumberton, NC: 96F (1962, 1941) Florence, SC: 93F (2022) N. Myrtle Beach, SC: 91F (1941) Saturday, May 17th... Wilmington, NC: 92F (1960, 1990) Lumberton, NC: 96F (1941) Florence, SC: 93F (1977) N. Myrtle Beach, SC: 92F (1941) && .ILM WATCHES/WARNINGS/ADVISORIES... NC...None. SC...None. MARINE...None. && $$ SYNOPSIS...DCH NEAR TERM...SHK SHORT TERM...DCH LONG TERM...DCH AVIATION...SHK MARINE...DCH/SHK CLIMATE...ABW/DCH ####018009470#### FXUS63 KLMK 160736 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 336 AM EDT Fri May 16 2025 .KEY MESSAGES... * Strong to severe thunderstorms are possible this morning west of Interstate 65, with large hail as the main hazard. * Greater chance of severe storms late this afternoon into tonight. All severe weather hazards are on the table, including damaging winds, large hail, tornadoes, and torrential rainfall. A few strong tornadoes and instances of very large hail are possible. && .MESOSCALE... Issued at 336 AM EDT Fri May 16 2025 Boundary has lit up from the Shawnee National Forest in southern Illinois ENE to near Henderson, and storms tapped into strong elevated instability to produce vigorous cores aloft. Given the very unstable and strongly sheared environment, as storms continue to develop through early morning they will carry mainly a SVR hail threat from the Pennyrile into the Hoosier National Forest and sections of Kentucky west of Interstate 65. Damaging winds and even a tornado or two can't be ruled out completely, but storms will have a really difficult time becoming sfc based. Confidence is also slightly diminished south of the WK Parkway but we could see convection down toward BWG later in the morning. && .SHORT TERM /THROUGH TONIGHT/... Issued at 352 PM EDT Thu May 15 2025 So far this afternoon, a summer-like air mass has spread into the Tennessee and Ohio Valleys as temperatures are in the low-to-mid 80s with dewpoints in the upper 60s and lower 70s. The surge in temperatures and moisture has come from deep southwest flow between a negatively-tilted trough which is morphing into a closed low over the Red River Valley of the North and ridging over the southeast US. Pressure falls to the north and west of the region have resulted in breezy S/SW winds this afternoon, and 20-25 mph gusts should continue into this evening. A very active stretch of weather is expected over the next 36 hours as the upper level disturbance to the northwest moves to the east. This afternoon and evening, our first chance of strong to severe storms will come from an ongoing cluster of cells over northern AR and southern MO. As these storms move to the east, they should encounter an increasingly unfavorable thermodynamic profile for sfc- based convection, and should also outrun the best forcing which will be near the sfc cold/occluded front and upper-level jet core over the mid- and upper-MS valley. Latest ACARS soundings show a warm capping layer between 850-700 mb, with surface-based LFCs up around the 700 mb level. However, the cluster of cells to our west could sustain itself if it develops a strong cold pool which could lift otherwise capped parcels to the LFC, and DCAPE ahead of the ongoing storms is fairly high (800-1200 J/kg). An elevated mixed layer atop the capping inversion has 8.5-9 degree C/km lapse rates within it, and a pool of around 3000 J/kg of MUCAPE would be available to parcels which break the cap. Would expect damaging winds and large hail to be the main threats with any storms this evening, and even if storms dissipate, gusty winds from the decaying cold pool/outflow would still be possible. This evening's threat should move quickly through the area between around 7 PM and midnight EDT. There should be a few hours of a lull in convective activity during the late evening and early overnight hours, though hi-res guidance shows another wave of storms trying to develop between 2-4 AM EDT. These storms are likely developing as a mid-level jet exit region noses across the lower Ohio Valley. Sounding profiles show continued instability aloft, though there should be a considerable amount of stability within the boundary. Accordingly, would expect mainly elevated storms late tonight into early Friday morning, with large hail as the primary threat. Any convection which develops should move off to the east and dissipate a few hours after sunrise Friday, and another lull is expected Friday morning. Any lull in convective activity Friday morning will give the atmosphere a chance to reload, resulting in instability and shear parameters which should be even more favorable for severe weather Friday afternoon and evening. As the upper closed low over the upper Midwest pivots to the east on Friday, troughing over the mid-MS valley should amplify, with height falls taking place over the region during the afternoon and evening hours. Near the sfc, increasing south-southwest flow should send a convectively-enhanced frontal boundary northward through the area tomorrow, with temperatures recovering into the mid 80s and dewpoints rising into the upper 60s and lower 70s. This should support MLCAPE values on the order of 2500-3500 J/kg, sufficient for explosive convection Friday afternoon and evening. Deep-layer shear on the order of 55-60 kts will help with storm organization Friday afternoon and evening, and a combination of discrete cells and bowing segments would be expected. Hi-res guidance has been fairly consistent in showing storms growing upscale into one or several large bowing lines, and DCAPE values of 1000-1200 J/kg support SPC's wind probabilities driving the moderate risk for tomorrow. Mid-level lapse rates will still be around 7.5 degrees C/km tomorrow afternoon, so the large hail threat will be supported if/while cells remain somewhat discrete. Looking at the hodograph and low-level shear profiles, while there is some curvature in the low-level wind field, relatively veered near-sfc winds will limit storm-relative helicity values. With this being said, any supercells which may develop would have an increased threat to produce strong tornadoes, and it is also possible that spin-ups could develop along the leading edge of any MCS/QLCS structures. Multiple waves of storms are possible Friday afternoon and evening, with storm coverage gradually winding down and pushing into eastern KY after midnight Friday night. All in all, the instability and shear parameters in place (especially tomorrow) support a significant severe weather event across the Ohio Valley. Make sure to have multiple ways to receive warnings and a plan in place should a warning be issued tonight through tomorrow night! && .LONG TERM /SATURDAY THROUGH THURSDAY/... Issued at 352 PM EDT Thu May 15 2025 By Saturday morning, the actual cold front will be pushing through the area with most of the showers and storms exiting to our east. The associated upper low will be over the Great Lakes with the longwave trough axis extending south over the OH and TN Valleys before flattening out against the subtropical ridge over the Gulf. Weak CAA behind the front will result in climatological normal temperatures for the weekend with highs in the mid to upper 70s to lower 80s accompanied by breezy WSW winds on Saturday. Overall, most will experience a fair weather weekend. Southern KY will see a slight chance of showers on Sunday as the southern edge of the new airmass begins to lift northward due to the next low pressure system strengthening over the Central Plains. This will begin another period of unsettled weather as we enter the beginning of the new work week. By Monday, a warm front will begin lifting across the region resulting in warm and moist air advection, as PWATs surge into the upper percentiles of SPC's sounding climatology. Models tend to agree on convection from our west moving into our area by Monday morning with another round Monday evening. The warm front appears to stall over the region, prolonging our shower and storm chances into Tuesday and Wednesday before the occluded low pushes through on Wednesday. With model soundings advertising sufficient instability and ML guidance also showing enhanced severe probabilities, severe weather can not be ruled out. Details remain hazy this far out, but will continue to monitor closely with subsequent forecast packages. Stay tuned. && .AVIATION /06Z TAFS THROUGH 12Z SATURDAY/... Issued at 137 AM EDT Fri May 16 2025 Main challenge in this TAF set is timing and impacts of two different potential waves of convection. Low-confidence forecast overnight as hi-res models show new development after ~08Z. Consensus timing on a morning wave would be starting 10-12Z for the terminals but could easily be focused just in the north on SDF and LEX or just south in BWG. Will carry a period of SHRA for now without any significant restrictions in cig/vis. Gusty SSW winds through the afternoon, and then another wave of storms comes in starting around 00Z, mainly for SDF and LEX. Handled those with TEMPO for IFR vis and gusty winds in the stronger storms. The evening storms could produce significant severe wind gusts, but this will be modulated by the behavior of morning storms, so will not hit that too hard just yet. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ MESOSCALE...RAS SHORT TERM...CSG LONG TERM...CG AVIATION...RAS ####018011758#### FXUS61 KPHI 160738 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 338 AM EDT Fri May 16 2025 .SYNOPSIS... A warm front lifts north across the area this morning. Periods of showers, thunderstorms, and humidity continue through Saturday ahead of a strong cold front that passes through late Saturday afternoon into Saturday evening. High pressure builds into the area on Sunday and persists into Tuesday before another period of unsettled weather returns Wednesday into Thursday. && .NEAR TERM /THROUGH TONIGHT/... 315 AM...It's relatively quiet across the area at the moment as weak ridging is briefly moving through. The main concern is areas of dense fog and so as a result, much of the area is under a Dense Fog Advisory through this morning. Otherwise, our attention turns to an MCS located upstream to our west. At this time it has started to weaken some as it moves across southern Ontario and Lake Erie though it's still producing quite a bit of lightning. This MCS is located near the triple point associated with a large and deep area of low pressure centered near Minnesota. As we get into the day Friday, our attention will turn to the MCS as it will be continuing to weaken but is likely to move into the area from west to east sometime beginning around the mid to late morning over our western most counties in eastern PA and reaching the I-95 corridor shortly there after as it should continue to be pretty quick moving. There remains some uncertainty regarding how strong it will be at this time as it moves into our area. But given that ML CAPE values will be increasing to 1000+ j/kg with bulk shear values around 35 to 40 knots certainly the potential is still there for severe weather. As a result, there has been little change to the outlook from the Storm Prediction Center as areas basically from near Allentown PA to Trenton NJ south and southwestward remain in a SLIGHT risk for severe weather with a MARGINAL risk to the north. Damaging winds and large hail look to be the biggest threats but a brief tornado or two cannot be ruled out. Finally, given how wet it's been and that these storms will be capable of producing very heavy downpours, localized flooding will also be possible. As we get further into the day Friday towards the afternoon and early evening, the forecast becomes a little more uncertain. Following the initial round of showers/storms with the MCS there are indications that more scattered convection develops as we go through the afternoon. This later convective development could on the one hand be aided by residual boundaries from the earlier convection but could also be mitigated if the MCS takes longer to move through since this would give the atmosphere less time to recover. Otherwise, the morning fog will have been broken up with the first round of convection moving through and we may even see some sunny breaks or partial sunshine for a time in the afternoon. But again, this could fuel convective redevelopment and this second round of storms could also be severe. It will be a warm and very humid day with highs generally ranging from the mid to upper 70s north to the low to mid 80s south. Right near the shore though it will be a bit cooler. For Friday night, there may still be some convection ongoing into the evening but this should diminish with time leading to another brief lull. Once again, there could be some low clouds, mist, and fog that form due to the continuing moist environment. The action won't be over though because by later Friday night the main slug of energy more directly associated with low will be approaching and this could bring another MCS into the area sometime either overnight Friday night or Saturday morning. There remains a lot of uncertainty on this though. Otherwise, it will be a mild, muggy night with lows mainly in the 60s. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Mid/upper level low over the Great Lakes will pivot east on Saturday as a vigorous shortwave tracks across the Mid-Atlantic with northwest flow developing in its wake on Sunday. At the surface, an area of low pressure will slide across Ontario/Quebec by Saturday night before meandering near Nova Scotia on Sunday. A strong cold front will pass through the area late Saturday afternoon into Saturday night. To start out Saturday, a MCS originating from the lower Ohio Valley is progged to approach our area on Saturday morning. The overall nature of this feature depicted by the latest CAM guidance is that it will be decaying or even dissipate as it approaches our area. A few showers and thunderstorms may be possible through the morning hours especially north and west, but since this feature is mesoscale driven, it's very difficult to depict where this feature may be come Saturday morning. Skies should be partly to mostly cloudy through the morning however, before clearing out by early afternoon. Temperatures will climb into the 80s for most areas with dew points in the low to mid 60s making it feel quite uncomfortable outside. The cold front will continue to make its way east through the afternoon where isolated to scattered thunderstorms will re-develop by the afternoon. In addition to the better forcing, we'll have MLCAPE values around 1000-1500 J/kg, DCAPE around 900 J/kg, and modest shear as indicated by point forecast soundings. These parameters will support damaging winds being the primary concern and possibly some severe hail. A brief tornado also cannot be ruled out as some low level shear will be in place. This is in line with the Storm Prediction Center which keeps the entire area in a Slight Risk (Level 2/5). Unfortunately, this threat is conditional and entirely dependent on the morning MCS and how it evolves, so the forecast may vary significantly by this time tomorrow. Nonetheless, the cold front will push off the coast by Saturday night and the threat for storms wanes in addition to the loss of daytime heating. Sunday is looking like the better half of the weekend as tranquil weather returns with the upper trough moving further east. Partly to mostly cloudy skies are expected with dry conditions and lower humidity. Perhaps an isolated shower is possible north and west, but general thinking is most of the area will stay dry. The one thing to note is winds will increase as diurnal mixing occurs as the area lies wedged between systems resulting in a tightening pressure gradient. Wind gusts up 30-35 mph will be possible. Gusts will diminish into Sunday night under mostly clear skies. Despite the windy conditions, high temperatures should mainly be in the 70s (with 60s in the Poconos). && .LONG TERM /MONDAY THROUGH THURSDAY/... By Monday, low pressure over the Canadian Maritimes will begin to move further east into the North Atlantic. At the same time, high pressure will settle over the Mid-Atlantic before moving offshore on Tuesday. Aloft, the area will be situated under northwest flow in wake of exiting upper trough. All in all, a tranquil weather period is in store with mostly clear skies, light winds and dry weather. By Tuesday night and through the middle of the week, our attention will turn to our next weather system which will take aim at the area. Global and ensemble guidance both feature a deep upper trough moving into the Great Lakes/Northeast region around the middle of the week with a potential coastal low developing before moving up towards New England. This would indicate another period of unsettled weather with periods of rain starting as early as Tuesday night, and more so on Wednesday and Thursday. Still quite a ways out from this potential, so have generally stuck with NBM guidance and capped rain chances at chance (~30-50%). In terms of temperatures, we'll encounter temperatures around average on Monday, before dipping below average for Tuesday through Thursday as the area remains situated within the deep upper trough. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Rest of overnight...Generally IFR to LIFR due to low clouds and fog. Winds light and variable to calm. Friday...Restrictions likely to start, then some improvement to MVFR expected between 15-18Z. However, around this time there will be a complex of showers and storms moving through as it moves in from the west but still some uncertainty on the details including how strong it will be at this time. Winds light and variable early in the day becoming SW 5 to 10 knots in the afternoon. There could be some additional showers/storms that form in the mid to late afternoon. Moderate confidence. Friday night...Any showers/storms diminish through the evening with with the potential for low cigs and low visbys once again due to stratus, mist and fog. Low MVFR or IFR appears likely. More showers and storms could move in late. S to SW winds around 5 knots. Low confidence. Outlook... Saturday through Saturday night...Primarily VFR expected. Scattered showers and thunderstorms likely, especially during the afternoon and early evening. Any shower or thunderstorm may cause temporary sub-VFR conditions, gusty winds and/or visibility restrictions. Sunday through Tuesday...VFR. Gusty winds up to 25-30 kt possible on Sunday. Otherwise, no significant weather expected. && .MARINE... Areas of dense fog over the waters likely to be an issue through the first half of Friday. Beyond this time, increasing chances for showers/storms over the waters in the afternoon. Generally sub SCA except any storms could produce locally strong winds. The risk for some showers/storms over the waters continues Friday night along with the potential for low visbys due to fog. Outlook... Saturday through Saturday night...No marine headlines expected. Sunday through Sunday night...SCA conditions possible due to wind gusts up to 25 kt. Monday through Tuesday...No marine headlines expected. && .TIDES/COASTAL FLOODING... A Coastal Flood Advisory was issued for the upper portions of the tidal Delaware River for minor flooding forecast at Burlington. Philadelphia should stay just shy of minor flood thresholds through the remainder of the week. Minor coastal flooding is forecast with the early morning high tides through Sunday morning as well, especially along the upper reaches of the tidal Delaware River. Additional advisories may be needed. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Dense Fog Advisory until 11 AM EDT this morning for PAZ054-055- 060>062-070-071-101>106. Coastal Flood Advisory until 8 AM EDT this morning for PAZ106. NJ...Dense Fog Advisory until 11 AM EDT this morning for NJZ001- 007>010-012>027. Coastal Flood Advisory until 8 AM EDT this morning for NJZ019. DE...Dense Fog Advisory until 11 AM EDT this morning for DEZ001>004. MD...None. MARINE...Dense Fog Advisory until noon EDT today for ANZ430-431-450>455. && $$ SYNOPSIS...DeSilva/Hoeflich NEAR TERM...Fitzsimmons SHORT TERM...DeSilva LONG TERM...DeSilva AVIATION...DeSilva/Fitzsimmons MARINE...DeSilva/Fitzsimmons TIDES/COASTAL FLOODING...PHI