FXUS61 KPHI 020535 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 1235 AM EST Mon Dec 2 2024 .SYNOPSIS... As high pressure remains centered to our south and southwest, a weak system slides by Delmarva tonight. High pressure crests across our area later Tuesday into Wednesday, then low pressure tracks to our north later Wednesday and Thursday pulling a cold front our area. Strong high pressure builds into the Ohio Valley Friday into Saturday before weakening into our area through Sunday. A weak low pressure system and front may slide by later Saturday. && .NEAR TERM /THROUGH TODAY/... The light rain and/or light snow over southern Delaware is tapering off, and skies will clear out into daybreak. Another cold night on tap for the region with lows edging into the teens north and west of I-95 and perhaps in the Pine Barrens of NJ, and the 20s elsewhere. High pressure builds in a little bit from the southwest on Monday, but the northwest flow picks up a little too, and with the upper trough overhead, a few snow showers may try to make their way into the Poconos later in the day. For now have kept this out of the forecast but its worth keeping our eye on. Highs look a bit more uniform than today, with near 40 across much of the region, except low 30s in the Poconos. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... A cold pattern continues. The axis of an upper-level trough is forecast to cross our area Monday night, however cyclonic flow aloft continues through Tuesday before it weakens Tuesday night. High pressure will build to our southwest and south with time then also extend across our area briefly Tuesday night into Wednesday. Much of this time frame looks to be on the dry and chilly/cold side, with perhaps a few snow showers extending into the Poconos Tuesday given ongoing eastern Great Lakes activity. Most of this activity should stay farther west though given light enough flow aloft. The passage of the trough axis aloft may result in some more clouds across parts of the area into Tuesday. A stronger upper-level trough is forecast to approach Wednesday and Wednesday night. This will support surface low pressure initially across or just north of the Great Lakes as it shifts eastward through Wednesday night. The track of this surface low is forecast to be well to our north, however the strength of the incoming trough and associated height falls should start to generate some forcing for ascent later Wednesday from west to east. The moisture however looks to be more limited especially with a southern extent and therefore how much precipitation is less certain. Most of the day Wednesday should be dry with any precipitation focused during Wednesday night. It looks cold enough across the far north for all snow with some mixing farther south to perhaps all rain even farther south given low-level warm air advection. Kept Pops at likely across the far north (generally the I-80 corridor) and then these taper down through chance and slight chance quickly southward. Given the quick movement and limited moisture overall, any precipitation should be on the light side and this could include some light snow accumulations mainly across the Pocono region. The low to mid level flow increases ahead of this system, therefore a breeze will increase especially later Wednesday. && .LONG TERM /THURSDAY THROUGH SUNDAY/... Summary...Another shot of cold air along with windy conditions to end the week. Some slight warming by the end of the weekend. Synoptic Overview...A strong upper-level trough is forecast to pivot across the East Thursday into Friday, then weaken some over the weekend. At the surface, low pressure is forecast to track well to our our north Thursday however a cold front sweeps through. The low deepens into the Canadian Maritimes Friday as strong high pressure builds into the Ohio Valley. The high builds closer to our area over the weekend but weakens, however a quick moving but weak low may track nearby over the weekend. For Thursday and Friday...A strong upper-level trough is forecast to pivot across the Mid-Atlantic and Northeast Thursday before weakening some on Friday. This will drive strengthening surface low pressure well to our north with it moving into the Canadian Maritimes Thursday night into Friday. Given the surface low tracking well to our north, most of the forcing and moisture should be to our north however strong shortwave energy within the trough will move across our area Thursday morning. This may be enough to keep some rain or snow showers going to start the day before notably drier air moves in. The main sensible weather is an increasing westerly wind especially in the wake of a cold front. Strengthening and deepening cold air advection, stronger flow, deeper mixing and a tightening pressure gradient will all result in breezy to windy conditions. As of now, looks like winds stay below Wind Advisory criteria with peak wind gusts of 30-40 mph. The winds should diminish some Thursday night, however a notable breeze should be maintained given the synoptic setup. It will turn colder in the wake of the cold front as well with widespread 20s Thursday night, then highs Friday only in the 30s for most (20s in the Poconos). A gusty west-northwest wind continues Friday adding an extra chill factor, however the winds may not be as strong as Thursday. For Saturday and Sunday...While the upper-level trough is forecast to not be as strong over the weekend, another shortwave may sharpen the trough some Saturday. It will be on the chilly to cold side, however with some less amplification of the trough the temperatures should start to rebound at least a little Sunday. In addition, the aforementioned shortwave within the main trough may support a weak surface low nearby and some precipitation cannot be ruled out. The winds will be much less as the pressure gradient is weak with surface high pressure starting to extend toward or into our area from the southwest. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas... Overnight...VFR. Clouds early KMIV/KACY. Winds W-NW around 5 knots. High confidence. Monday...VFR. Northwest wind 5-10 kts. High confidence. Outlook... Monday night and Tuesday...VFR. Wednesday...A period of sub-VFR conditions possible along with a chance of some rain/snow showers mainly at night. Thursday...Any sub-VFR conditions improve to VFR. West winds 15-20 knots with gusts 30-35 knots. Friday...VFR. West-northwest winds 10-15 knots with gusts 20-30 knots, diminishing in the evening. && .MARINE... Conditions will remain below advisory levels through Monday across all coastal waters. Westerly to northwesterly winds of 10-15 knots with gusts up to 20 knots and seas of 2-4 feet are expected throughout the period. Outlook... Monday night and Tuesday...The conditions are anticipated to be mostly below Small Craft Advisory criteria. Wednesday...Small Craft Advisory conditions develop, with gales possible at night. Thursday and Friday...Small Craft Advisory conditions. An increasing chance for gale conditions especially Thursday and Thursday night. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ SYNOPSIS...Gorse NEAR TERM...MPS/RCM SHORT TERM...Gorse LONG TERM...Gorse AVIATION...Gorse/MPS/RCM MARINE...Gorse/RCM