####018009639#### FXUS61 KPHI 070758 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 258 AM EST Sun Dec 7 2025 .SYNOPSIS... Weak high pressure moves offshore today before dissipating. A cold front will cross through the area tonight, followed by Arctic high pressure which will build across the Great Lakes and dominate through Tuesday. An area of low pressure will impact the region on Wednesday with its associated fronts. Brief high pressure returns on Thursday, followed by a clipper system Thursday night into Friday. High pressure should then return by next weekend. && .NEAR TERM /THROUGH MONDAY/... Through Sunday morning, the key message is freezing fog, primarily in Delmarva. Some freezing fog has developed especially on portions of the MD eastern shore, so have issued a freezing fog advisory for those areas as well as central and southern Delaware. Looking at pavement sensors, most pavement temperatures are hovering right above freezing, so the main concern with any icing will be on bridges, but also can't rule out isolated slippery conditions on untreated roads. Then, our attention turns to the cold front moving in tonight into Monday morning. It still appears that the front itself will be mostly dry for our area (though can't rule out a few flurries, especially for the southern Poconos). The main impacts will be the dramatic temperature difference and wind changes. Guidance tends to have a low bias with arctic cold air advection regimes even if the trough isn't very amplified (as this one doesn't appear to be), so have included wind speeds and gusts on the higher end of guidance. Even so, should stay well below wind advisory thresholds. The peak gusts in our region will likely be in the 35 to 40 mph range. Temperatures on Monday are expected to be 5 to 10 degrees lower than Sunday, with highs only ranging from the lower 20s to mid 30s. Wind chill values are expected to be in the teens and 20s. Also of note on Monday, one of the high res models - the HRRR - depicted the low forming off the southeastern US coast on Monday considerably further north that other models. If this were to verify, it would mean that snow (albeit light in our area) would be possible as far north as South Jersey. For now, this appears to be an outlier, so have stayed close to the blend of guidance. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... The short term period as a whole is highlighted by a blast of very cold temperatures (as much as 10-20 degrees below normal). Large and expansive Arctic high pressure will exit the Great Lakes region and settle overhead for Monday night. This high will shift east off the coast of New England on Tuesday with southerly return flow returning late in the day into Tuesday night. Monday night will by far be the coldest night of the week and likely so far this season for most locales. With the high essentially settling directly overhead, light northerly winds should become calm at times, and with clear skies, this should equate to optimal conditions for radiational cooling. Low temperatures ranging from the single digits to upper teens appear likely. Considering the set- up in place, considered blending in some colder guidance, which would result in temperatures below zero in some spots. As of now, cold weather headlines do not appear to be warranted, however. For Tuesday and Tuesday night, high pressure departs but will still largely be in control with dry weather conditions. Return flow will shift to more southerly, allowing temperatures to moderate some, yet remain well below normal. Skies will be mostly clear to start the day, but an increase and thickening of clouds are expected come Tuesday night. High temperatures in the low 30s to low 40s are expected with lows in the low 20s to low 30s for most of the area. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... The long term pattern then becomes more active across the Eastern US with several areas of low pressure and their associated fronts taking aim at the area. Guidance has come into better agreement with Wednesday's system as a rather strong shortwave tracks through the Great Lakes with an upper level low meandering within the vicinity of the Hudson Bay. At the surface, low pressure will track out of the Great Lakes and across southern Quebec into Wednesday night. As it does so, its associated cold front will cross through the Mid- Atlantic region. This will be the next opportunity for much of the area to recieve some kind of precipitation. With the region located well south of the low center, so its likely that this precipitation will be mostly in the form of rain...although some snow cannot be ruled out in the Poconos. Temperatures for Wednesday will be close to average. Following the frontal passage, temperatures are expected to dip back below average for Thursday as some weak ridging at the surface returns. Aloft, the Mid-Atlantic will remain nestled well under the deep trough, yielding the continuation of cool weather. Beyond Thursday and continuing into next weekend, guidance diverges significantly with the timing, position and strength of features. As of now, it does appear that will be some sort of 'clipper-like' system that will move into the region Thursday night into Friday. This system looks to be a rather quick mover, but temperatures will be cool thanks to the frontal passage the day prior. This could result in a period for light snow and/or light rain across the area, but ultimately comes down to timing and the track of the low. For this reason, kept NBM guidance which depicts a 30-50% chance of light rain/snow across much of the area. Behind this system though, will be another period of dry weather but very cold temperatures for next weekend. Early indications are for daytime highs to struggle to reach the freezing mark at times. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Through 12Z...Prevailing VFR for most TAF sites with a ceiling around 4000 ft AGL. However, for RDG, ILG, ACY, and especially MIV, periods of BR or freezing fog will lead to visibility reductions, mostly in the MVFR category. At MIV and locations further south, a 200 ft ceiling has also developed leading to prevailing LIFR conditions. Sunday...VFR. Southwesterly wind around 5 kt. High confidence. Tonight...VFR expected. Between 03 and 09Z, expect an abrupt shift to northwesterly winds with wind speeds increasing to 10g20kt. Outlook... Monday night through Tuesday night...VFR. No significant weather expected. Wednesday through Wednesday night...Sub-VFR conditions possible at times. A chance for rain at all terminals, with a slight chance of snow at KRDG and KABE. Wind gusts in excess of 20 kt possible. Thursday...VFR. A slight chance of rain, otherwise no significant weather expected. && .MARINE... Winds and seas will stay below Small Craft Advisory conditions today into this evening. Late tonight into early Monday Morning, a cold front will cross over the waters, bringing an abrupt shift from southwesterly to northwesterly winds. Wind speeds will also increase quickly behind this front. Wind gusts near or above 30 kt are forecast. A Small Craft Advisory is in effect for the Atlantic Coastal Waters and the Delaware Bay starting Late Tonight and continuing through the day time on Monday. Winds are expected to slowly begin to subside Monday Afternoon, but it may take time for the seas to subside. Outlook... Monday night...Lingering SCA conditions likely with wind gusts up to 20-25 kt and seas around 3-6 feet. Tuesday...No marine headlines expected. Tuesday night through Thursday...SCA conditions likely with a brief period of gales possible on Wednesday. Seas may build in excess of 8 feet. && .TIDES/COASTAL FLOODING... Now several days removed from the Full Moon phase that occurred on December 4th, expect one more round of spotty minor tidal flooding with this morning's high tide cycle. This is primarily for the NJ and DE coasts and lower Delaware Bay. No tidal flooding is expected elsewhere. && .CLIMATE... Very cold Monday Night into Tuesday Morning. At this point, we aren't forecasting to break any record lows. Below are the record lows for December 9. SITE RECORD/YEAR Allentown (ABE) 7/2002 AC Airport (ACY) 6/1968 AC Marina (55N) 5/1876 Philadelphia (PHL) 6/1876 Wilmington (ILG) 13/1960 Reading (RDG) 0/1989 Trenton (TTN) 12/2002 Mount Pocono (MPO) -1/1902 Georgetown (GED) 10/1976 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...Freezing Fog Advisory until 9 AM EST this morning for DEZ002>004. MD...Freezing Fog Advisory until 9 AM EST this morning for MDZ012- 015-019-020. MARINE...Small Craft Advisory from 1 AM to 6 PM EST Monday for ANZ430- 431-450>455. && $$ SYNOPSIS...DeSilva NEAR TERM...Johnson SHORT TERM...DeSilva/Staarmann LONG TERM...DeSilva/Staarmann AVIATION...DeSilva/Johnson MARINE...DeSilva/Johnson TIDES/COASTAL FLOODING...PHI CLIMATE...PHI ####018006385#### FXUS63 KAPX 070759 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 259 AM EST Sun Dec 7 2025 .KEY MESSAGES... -Light snow across northern lower today, with lake effect possible near Whitefish Point through the day. -Cold tonight with subzero lows on the table across the interior. -Several waves set to pass through the long term forecast period... specifically Monday night, Tuesday night - Wednesday, and again this weekend. Lake enhancement / lake effect possible at various times with these wave passages. && .SHORT TERM /THROUGH TONIGHT/... Issued at 259 AM EST Sun Dec 7 2025 Robust longwave troughing over eastern NOAM remains locked into place... with a weak impulse currently over Wisconsin continuing to be forced eastward by strong, cold west / northwesterly flow. Weakening thermal gradient and lack of supporting jet dynamics will essentially translate to a light snowfall across much of lower Michigan through the morning hours... perhaps 1 to 2 inches of accumulation, locally up to 3" along the Lake Michigan shores. In the wake of this system, will see some light lake effect activity across the NNW to NW flow snowbelts. Moisture is a bit lacking as upstream subsidence intruding. In addition, weak pressure gradient will continue to lead to land- lake breeze shenanigans off Lake Superior today into tonight, which may feed an additional 2 to 4 inches of snowfall across western Chippewa County (think Paradise / Whitefish Point). Will have to watch this feature closely... the theme from previous forecasts still holds, as there is always potential for convergence driven bands of snow / mesolow generation, but guidance doesn't seem to jump all over this idea... so will have to continue to keep a watch out for that. Meanwhile, big upstream 1030+ mb surface high with arctic origins over the northern Plains and Canadian prairies will charge south and east into the Great Lakes... which will eventually put an end to the snow activity... with winds decoupling and skies clearing across much of the area into tonight, save for the NW lower shoreline and portions of eastern upper. As such, our natural "refrigeration unit"... aka... the established snowpack... will be put into overdrive across the interior of northern lower. While shoreline locales probably stall out in the single digits into the teens... interior locales seem like a solid bet to be below zero by Monday morning. Wouldn't be overly surprising to see the interior "icebox" areas (Grayling, Mio, Atlanta) make a run at -10. && .LONG TERM /MONDAY THROUGH SATURDAY/... Issued at 259 AM EST Sun Dec 7 2025 The active wintry pattern continues its influence across the region through the remainder of the forecast period. Monday - Tuesday: Following what will likely be the coldest morning of the young winter season thus far, we will trend right back into an active regime with another quick moving clipper-like system passing through the Great Lakes. Synoptic snowfall looks marginal at best... most places probably wind up with a general 1 to 3 inches of snow later Monday night into Tuesday. That being said... with the cold locked into place, antecedent SSW flow looks to kick off a SSW flow lake effect boundary off Lake Michigan that could set its sights on Mackinac County (in particular, the western part of the county) and perhaps far SW Chippewa. This area could see totals in excess of 6 inches from this event. In the wake of the system... perhaps some lingering westerly flow lake effect. Definitely one to keep our eyes on. Tuesday night - Thursday: No time to put our feet up just yet, as another system... this time with a bit more beef to it... looks to quickly pass through later Tuesday night into Wednesday, and could deliver a bigger swath of snow to the region. Current probs for 4" of accumulation through Wednesday evening sit at 60% across much of the area, slightly lower in eastern upper... and touching 40% across interior northern lower for totals reaching 6 inches across northern lower. This system will have a superb warm advection surge to drive the snowfall... so will have to watch thermodynamics, especially the farther south one goes... as surface temps may balloon high enough to lead to some rain mixing in if higher end warm advection can be realized, and snow ratios in general may be lower than current guidance is depicting (outside of any FGEN bullseyes). Lake effect snow showers seem like a good bet on the backside of this system as colder air surges back into the region, which would primarily be a Wednesday night - Thursday phenom. Friday / Weekend: The core of an arctic airmass looks to make its way through the region, sending temperatures well below normal across the Northwoods. Preceded by a shortwave and persistent cold advection, this looks like it could feature prolonged lake effect snow potential across the snowbelt locales. For the time being, looks like several days with highs generally in the teens to near 20 and lows in the single digits. As such, for those looking to cash in on the early onset of winter activities may contend with snowy conditions on area roads when making the trek up to the Northwoods. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1146 PM EST Sat Dec 6 2025 Low-end VFR cigs will be pretty typical at the TAF sites thru the forecast, with a chance for some snow showers. TVC/MBL will see a period of -SHSN late tonight/Sunday morning, with MVFR cigs and borderline IFR/MVFR vsbys at times. Best chance for IFR conditions early Sunday morning is at MBL. Light winds tonight, a northwest breeze kicks in Sunday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory from noon today to 10 PM EST this evening for LHZ345>349. Small Craft Advisory from noon today to 10 PM EST this evening for LMZ323-341-342-344>346. Small Craft Advisory from noon today to 10 PM EST this evening for LSZ321-322. && $$ SHORT TERM...HAD LONG TERM...HAD AVIATION...JZ