834 FXUS61 KPHI 132305 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 605 PM EST Mon Jan 13 2025 .SYNOPSIS... A cold front will move across the area through this evening and offshore tonight. High pressure builds cross the southeast for Tuesday through Thursday, keeping west to northwest flow across the area. A cold front will weaken as it approaches Thursday, then a warm front lifts north of the area Friday. A cold front is expected to move across the area later Saturday into Saturday night. A coastal low may impact the area later Sunday into Sunday night. && .NEAR TERM /THROUGH TUESDAY/... Just minor tweaks made to the forecast, but overall, it is on track. The cold front is crossing the area at this hour, and will move off the coast around midnight. This will result in mostly clear skies after midnight. In wake of the front, should observe an increase in surface winds where winds may occasionally gust up to 20 mph overnight. Overnight low temps will range from the teens to mid 20s across the region so when factoring in the wind, we`ll likely have wind chills in the single digits to low teens by Tuesday morning. For Tuesday, cold Canadian high pressure will build out of the High Plains, slowing inching toward the Mid-Atlantic region. This will be the start of a reinforcing cold airmass through mid-week. Temps will struggle to reach the freezing mark with many locations topping out in the 20s to low 30s for highs under partly to mostly cloudy skies. A shortwave aloft will also be passing through in the afternoon, so may see some isolated flurries late in the day north and west of the I-95 corridor. Confidence in this is low as the airmass behind the front is quite dry, so have left this potential out of the forecast grids at this time. In addition to the cold temps, a modest pressure gradient will set-up over the region. So, Tuesday will be quite breezy with wind gusts up to 30-35 mph possible. This should result in wind chills remaining in the teens for Tuesday afternoon. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... For Tuesday night through Wednesday night, high pressure will build across the Ohio River Valley and weaken as it approaches the southeastern states. Meanwhile, low pressure drifts offshore of the Canadian Maritimes. In between the two, a tight pressure gradient will keep a steady west to northwest flow across the area. Winds will likely gust 20-30 mph or higher at times through Wednesday. Winds will weaken some by Wednesday night. For Thursday, high pressure dissipates to our south, as a cold front weakens as it approaches from the west. As the front approaches and weakens, there is a chance for snow showers to move into the western half of the area during the afternoon. Temperatures for Tuesday night through Thursday will be below normal. && .LONG TERM /FRIDAY THROUGH MONDAY/... On Friday, a warm front will lift north of the area, allowing temperatures to moderate back above normal. As we move into Saturday into Saturday night, a cold front is expected to move across the area. Most areas will be warm enough for any precipitation that starts our as snow to change over to rain during the day Saturday. The front will shift offshore by Saturday night, then there is a chance a developing coastal storm could affect the area later Sunday into Sunday night. && .AVIATION /23Z MONDAY THROUGH SATURDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas... Tonight...VFR with mostly clear skies. Westerly winds around 5-10 kt, with gusts up to 20 kt increasing in frequency after midnight. High confidence. Tuesday...VFR. Mostly clear skies early with SCT/BKN ceilings in the afternoon. West-northwest winds around 10-20 kt with gusts up to 25- 30 kt. High confidence. Tuesday Night...VFR. Gusts gradually weakening as the night goes on, though still will be around 20-25 kt out of the west/northwest. High confidence. Outlook... Wednesday through Wednesday night...Generally VFR. Gust winds 20-30 knots Tuesday through Wednesday. Thursday-Friday night...Generally VFR. Saturday...Sub-VFR conditions possible with a chance of showers. && .MARINE... A Small Craft Advisory is in effect for all Atlantic coastal waters including the Delaware Bay beginning tonight through Tuesday. West-southwest winds up to 20 kt this evening will shift to west- northwest tonight around 15-25 kt with gusts up to 30 kt. These wind conditions will persist through Tuesday. Seas around 4-6 feet. Fair weather skies expected. Due to the combination of cold air/water temperatures, gusty winds and enhanced seas, freezing spray will be likely on both the Atlantic coastal waters and Delaware Bay on Tuesday. Outlook... Tuesday night...Gale Warning in effect. Light freezing spray likely. Wednesday-Wednesday night...Light freezing spray likely in the morning. Small Craft Advisory Conditions likely. Thursday-Friday night...Conditions expected to be below advisory levels. Saturday...Small Craft Advisory conditions possible. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 11 PM this evening to 6 PM EST Tuesday for ANZ430-431-454-455. Gale Warning from 6 PM Tuesday to 6 AM EST Wednesday for ANZ430-431-450>455. Small Craft Advisory until 6 PM EST Tuesday for ANZ450-451. Small Craft Advisory until 6 PM EST Tuesday for ANZ452-453. && $$ SYNOPSIS...Robertson NEAR TERM...DeSilva/Hoeflich SHORT TERM...Robertson LONG TERM...Robertson AVIATION...DeSilva/Hoeflich/Robertson MARINE...DeSilva/Hoeflich/Robertson