####018007999#### FXUS61 KOKX 170250 AFDOKX Area Forecast Discussion National Weather Service New York NY 1050 PM EDT Fri May 16 2025 .SYNOPSIS... A warm front draped over portions of the Mid Atlantic lifts north through the region tonight into early Saturday. An attendant cold front follows, with the passage expected Saturday evening. A secondary cold front passes Sunday night. Low pressure lingers in New England and the Canadian Maritimes Sunday through Monday. High pressure takes control Monday night into early Tuesday night. Another frontal system impacts the area Wednesday into Thursday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Digging trough and upper low over the Upper Midwest swings east across the Great Lakes region, sending an associated frontal system toward the region. Warm front analyzed to the southwest over the Mid Atlantic begins to approach and lift through tonight. With multiple spokes of vorticity rounding the trough, there will be a chance of showers and still a chance of a thunderstorm late tonight pushing in from the west. Only other shower activity before this would be any showers popping up offshore to the south as a shortwave passes through and taps into a little bit of elevated instability. Otherwise, likely see areas of fog development once again overnight with light flow and abundant surface moisture. Not thinking the fog will be as widespread or as dense as it was last night since winds near the top of the boundary layer are stronger this time. Still can't completely rule out dense fog in a few hours. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Upper level low and trough over the Great Lakes pivots east on Saturday, as a vigorous shortwave tracks across the Mid Atlantic. A warm front lifts thru by the morning, as the associated surface low slides into Quebec. The attendant cold front looks to move through locally in the early to mid evening. A challenging convective forecast with uncertainty on timing and coverage of any morning activity. The approaching cold front adds more in the way of forcing as the day progresses, and breaks in the clouds should develop by the afternoon. 12z HREF is progging MLCAPE values as high as 1500 J/kg, along with bulk shear values 30 to 40 kt. That said, cloud cover could limit this instability, and subsidence behind any previous MCS could help to cap the low levels as well. It now appears the core of the shortwave energy passes north and west by mid afternoon, and could help limit any organized severe threat locally. With this, SPC has lowered their threat locally from a slight to a marginal, which seems reasonable based on the above and continued uncertainty. CAMs aren't overly aggressive in depicting convective development, but should initiation occur, damaging wind gusts would be the primary threat, though large hail and even an isolated tornado cannot be ruled out in the environment. Coverage looks isolated to scattered, especially across the LoHud Valley and southern CT. Cold frontal passage progged around 00Z Sun, and behind it winds veer westerly into the overnight, with drying conditions overnight as dew pts fall back into the lower 50s by daybreak. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Key Messages: * Mainly quiet & pleasant weather Sunday through Tuesday. * A frontal system may will bring rainfall Wednesday, possibly into Thursday and Friday. A surface low w/ an associated upper-level low will be located over New England Sunday. This low will exit into the Canadian Maritimes by Monday. This low will bring a second cold front through on Sunday night helping clear out partly to mostly cloud skies and advecting in drier air. This leaves late Sunday night into Monday mostly clear/sunny. A few showers are possible in the northern interior, closer to the periphery of the low Sunday afternoon/evening, but chances look quite low. A quick moving shortwave will pass over or just to the north of the area Monday afternoon/evening. This may lead to a few clouds, but otherwise, we will remain clear and sunny late Sunday night through most of Tuesday. An increased pressure gradient from the low to our northeast will lead to breezy W/NW flow Sunday and Monday. As the low exits farther away, the gradient weakens, leaving light winds by Monday night. It remains this way with high pressure at the surface through Tuesday. 12Z guidance still varies in timing and track of a frontal system for the middle of next week. A low over TN/KY late Tuesday will approach the area Tuesday night and pass near or to the south of the area Wednesday into Thursday, pushing more north and/or east of the area on Friday. This will bring a period of wet weather. There is higher confidence in showers on Wednesday, but confidence is lower Thursday and especially Friday and models diverge on a solution. Sunday and Monday will see highs in the upper-60s to mid-70s, right around the climatological average. Temperatures will be much cooler from a passing frontal system on Wednesday with highs in the low-60s under E/NE flow. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... A warm front moves partially through the area tonight then advances further north on Saturday. A cold front follows for Saturday evening. Conditions lowering to IFR everywhere tonight, improving to MVFR mid-morning Saturday, then VFR in the afternoon. PROB30 for TSRA Saturday afternoon into early evening. Southerly flow 5-10 kts expected through mid-morning Saturday, then southerly winds pick up to 10-15 kt with some gusts up to 20 kt in the afternoon. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Timing of category changes could be off by a couple o hours. Tempo or prevailing vsbys of 1/4sm possible at KJFK from 08-12z Sat. .OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY... Saturday: Mainly VFR but MVFR possible in the afternoon with chance of showers and thunderstorms with MVFR or lower conditions possible. Sunday: Mainly VFR. Slight chance of showers inland with MVFR possible. W winds G20-25kt. Monday - Tuesday: VFR. Monday NW winds G20-25kt day into evening. Wednesday: MVFR or lower with showers likely, mainly at night. E wind gusts 15-20 kt. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Areas of fog likely return tonight, potentially becoming dense and persisting into mid Saturday morning. A Dense Fog Advisory may be needed, with the potential for vsbys to fall to less than 1 nm at times overnight into Saturday AM. Winds and waves remain below Small Craft Advisory (SCA) criteria through at least Saturday night. Sunday afternoon and evening, wind gusts may marginally reach SCA criteria for the NY Harbor, western Sound and western Ocean. Otherwise, sub SCA conditions are expected on all waters thereafter through Wednesday. A passing frontal system will lead to ocean seas climbing 5-7 feet Wednesday night through Thursday night. && .HYDROLOGY... Locally heavy downpours are possible with any thunderstorms through Saturday aft/eve. While the overall flash flood threat is low, the brief heavy rainfall could lead to minor nuisance flooding in urban and poor drainage areas. There are no other hydrologic concerns through the end of next week. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...BR/DR NEAR TERM...JC SHORT TERM...DR LONG TERM...BR AVIATION...JC/JM MARINE...BR/DR HYDROLOGY...BR/DR ####018008252#### FXUS61 KGYX 170251 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1051 PM EDT Fri May 16 2025 .SYNOPSIS... A slow moving low pressure system will bring rounds of showers and thunderstorms tonight and through the weekend. Storms through tonight may be slow-moving, potentially leading to localized flash flooding north of the mountains. Saturday, storms may be more organized, leading to some stronger storms across NH as well as a potential flash flooding threat again north of the mountains. && .NEAR TERM /THROUGH SATURDAY/... 1045 PM Update... An area of heavy rain is currently slowly tracking east over the western ME mountains with some embedded thunder at times. Some locations under this area of rain could receive up to 1" of rainfall within an hour or so. Elsewhere, there is little activity on radar but the next round of thunderstorms is already approaching from central VT within a region of higher MLCAPE. This activity will be sub-severe but could produce locally heavy rainfall once again. Where it did rain earlier, fog has developed and it has become dense in spots. It will remain a mild and somewhat muggy night. Previously... 745 PM Update... Weakening thunderstorms are continuing to slowly push eastward at this hour across north-central NH and interior western ME. Storm strength has been on a noticeable decline with the loss of daytime heating and therefore the threat for gusty winds/hail has ended but locally heavy rainfall remains possible. Along the Mid- Coast, fog is moving onshore with KRKD already down to 1/4SM. Will monitor trends to determine if a dense fog advisory will be needed. Made some adjustments to PoPs, temperatures, and sky cover but the overall forecast thinking remains on track. Previously... Radar imagery currently shows numerous pulse thunderstorms across the interior. These storms are producing heavy downpours, and may have the potential to produce some gusty winds and small hail as well. Storms are slow moving and there is some training, so localized flash flooding may occur with some heavier storms. Coastal areas should stay mostly dry this evening, as the sea breeze should keep more stable air over the coast. After the frontal passage late tonight, marine fog builds back into the coastal plain. Scattered showers and developing fog overnight should allow for mild low temperatures tonight, with lows in the 50s and 60s. && .SHORT TERM /SATURDAY NIGHT THROUGH 6 PM SATURDAY/... Key Points: -Rounds of storms tomorrow may bring damaging winds and localized flash flooding to New Hampshire and western ME. The damaging wind threat looks to be across southwestern New Hampshire, while the flooding threat tomorrow is highest from the foothills and points north. -The SPC has issued a Slight Risk for Severe Weather in Southwest NH -The WPC has issued a Slight Risk for a 15% chance of excessive rainfall from the foothills and points north. Details: Visibility restrictions will be possible through most of the day tomorrow as very light onshore winds continue to advect fog into much of western Maine. Fog will keep high temperatures across Maine lower, and keep the environment more stable. Over western and southern NH, there should be thinner clouds with more breaks in them. This will allow for warmer high temperatures and allow for the environment to destabilize, becoming more conducive for severe weather. The environment tomorrow afternoon features 1000-1500J/kg of CAPE, some wind shear and 100m^2/s^2 of low-level helicity. These parameters suggest that damaging winds and hail are possible with thunderstorms across southwestern NH. In addition, multiple rounds of showers and storms across the north tomorrow may produce some localized flash flooding as well. The strongest storms move across western NH in the mid-afternoon, with another round of storms possible later on in the evening. Fog over Maine will allow for the marine layer to advect all the way to the mountains, with most storms weakening as they enter these areas of fog. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... 1045 PM Update... Little change in the latest NBM suite of guidance. The main story of next week will be for below normal temperatures for mid to late May. Previously... The surface low will exit into Downeast Maine Sunday morning while the 500 mb crosses overhead through the day. There could be fog and low stratus lingering in the morning, especially over eastern areas, but otherwise the upper low will bring another day of high shower coverage during the day and into Sunday night, especially inland and toward the mountains with activity more scattered farther south and closer to the coast. I don't think there's enough instability to include thunderstorms in the forecast at this point as models are mostly showing on the order of a couple hundred J/kg of CAPE. The upper low shifts east of the area early next week to around Nova Scotia, but broad troughing across the NE and enough residual moisture will still be sufficient enough for isolated to scattered showers to develop (lower coverage than Sunday), mainly during the daytime hours. Temperatures will be in the mid 50s to lower 60s for the most part on Monday and then a touch cooler on Tuesday. Another slow-moving, upper low then enters the picture for the second half of next week with models in good agreement a 500-mb low closing off near the Great Lakes that will slowly head toward New England. Shower chances will ramp back up as a result with cloudier conditions and temperatures staying on the cooler side. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Short Term... Thunderstorms and fog will keep restrictions mostly down this evening, likely continuing through Saturday and Saturday night as fog and multiple rounds of showers and storms move across NH and ME. Long Term...LIFR to IFR fog and/or stratus may stick around 12-15Z Sunday, mainly in the RKD-AUG corridor...otherwise showers will again be likely during the day Sunday into Sunday and could produce IFR to MVFR conditions. For Monday and Tuesday...MVFR ceilings possible during the first part of Monday, but coverage of showers will be lower and mostly during the daytime hours these days. Chances for showers and and flight restrictions then increase toward the middle of next week. && .MARINE... Short Term... 2-4ft seas expected this evening through Sunday morning. This afternoon, winds will be southerly at 6-11kts. Winds strengthen to 8- 13kts Saturday morning ahead of a frontal boundary. The frontal boundary crosses the waters tomorrow night, with winds shifting to westerlies at 6-11kts by Sunday morning. Long Term...Winds become westerly Sunday and then northwesterly Monday into Tuesday as surface low pressure moves east of the waters. Gusts to 20-25 kt may occur from time to time during this period, but in general things look to remain under SCA levels through Wednesday. Winds become east to northeast toward the second half of next week with developing low pressure to the south. It's uncertain what track the low will take, but SCA conditions are possible toward late week. && .HYDROLOGY... Torrential downpours with rain rates as high as 1-3" per hour from slow-moving showers and storms will pose a risk of flash flooding through this evening, mainly from the mountains northward. Multiple rounds of showers and storms are again possible during the day Saturday and could pose another threat of flash flooding. The threat is highest from the foothills and points north on Saturday where WPC has highlighted a Slight Risk of Excessive Rainfall. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Tubbs SHORT TERM...Palmer LONG TERM...Combs/Tubbs