textproduct: Philadelphia/Mt Holly

SYNOPSIS

A weak clipper system will pass by to the north on Sunday. High pressure moves in Sunday night through Tuesday morning, with a frontal system moving in for the mid-week period. High pressure takes over in the wake of the frontal system for the Thanksgiving holiday through the end of the week, resulting in dry but cold weather.

NEAR TERM /THROUGH MONDAY/

Northwesterly flow aloft will continue through the morning hours. A mid-level impulse will pass just to the north of the region this afternoon. Heights will begin to rise with the passage of the impulse and will continue to rise through the day Monday. At the surface, a weak low pressure system will track through southern Ontario and Quebec today, and through far northern New England tonight. A trailing cold front will pass through the region tonight. High pressure will build into the area in its wake.

It is a chilly morning across the area with temperatures largely in the upper 20s to lower 30s. Fog this morning has been very localized and transient. This should remain the trend, with all fog dissipating within a few hours after sunrise.

Skies today will be partly to mostly cloudy. High temperatures will generally be in the low 50s north of I-78 and the mid 50s south. In the Poconos and into far northwestern NJ, temperatures may struggle to get out of the low 40s. Most will be dry today. However, there will be a slight chance (around 20%) for a few rain or snow showers in the aforementioned areas. Impacts would be minimal if this were to occur.

With the passage of the cold front tonight, skies will become mostly clear. Lows look to be in the low-mid 30s areawide. Monday will be mostly clear to start, with increasing clouds late. Highs look to be in the low 50s outside of the higher elevations, where they should remain in the mid-upper 40s.

SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/

Quiet on Monday Night as high pressure moves overhead and offshore. Clouds increase ahead of the mid-week system, which will prevent temperatures from bottoming out completely. With the cold airmass in place though, temperatures will still fall into the low to mid 30s.

On Tuesday, a warm front will be lifting northward through the area which is attached to a deepening low pressure system near the Great Lakes region. This warm front along with the high pressure system moving offshore will set the stage for warmer air to filter in Tuesday into Tuesday night. We are cloudy Tuesday with rain starting to move in by midday and becoming more widespread Tuesday evening. Highs on Tuesday are in the low 50s to low 60s.

Periods of rain continue Tuesday night into Wednesday. The first cold front with the deepening low now moving into Canada will move through Wednesday night. This will result in more periods of rain into Wednesday night. In the temperature department, we see lows Tuesday night in the mid 40s to mid 50s. Highs on Wednesday are in the 60s for most. By Wednesday night, lows are in the 30s for many. Starting to get within range of the QPF period, though not fully in it yet to capture the mid-week system. However, the NBM Probability of rainfall over 1" is less than 10% region-wide. Overall, this system looks like a beneficial rain more than anything though Tuesday through Wednesday Night is shaping up to be a damp and dreary stretch.

LONG TERM /THURSDAY THROUGH SATURDAY/

The secondary cold front comes through on Thursday, ushering in a stretch of below normal temperatures. Strong cold air-advection should set up with an incoming area of high pressure and departing low pressure, setting up a tight gradient and rush of cold air from Canada. The result will be a breezy set of days to close out the week, though it should be dry for both Thanksgiving and Black Friday. Still too early to say exactly how strong wind gusts will be both days, but would expect a period of blustery conditions with below normal temperatures.

High pressure slides in Friday Night into Saturday, which will put an end to the windy conditions. Still looking at below normal temperatures for next weekend, though with some moderation. Dry weather should continue through at least Saturday with the high in the vicinity of the Mid-Atlantic.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas.

Today...VFR. SCT/BKN mid-level clouds. Light wind becoming west-southwest and increasing to 5-10 kt by 15-17Z. High confidence.

Tonight...VFR. West-northwest wind around 5 kt. High confidence.

Monday...VFR. Northwest wind around 10 kt.

Outlook...

Monday night...VFR. No significant weather.

Tuesday...Primarily VFR, though conditions likely deteriorate as the day goes on dropping to MVFR by the late afternoon/early evening with rain showers moving in.

Tuesday Night through Wednesday...MVFR/IFR conditions expected with periods of rain and low clouds in place.

Wednesday Night...Conditions likely improving to VFR late, but MVFR/IFR restrictions possible (40-60%) for at least part of the night.

Thursday...VFR. Wind gusts out of the west/northwest around 20-30 kt.

MARINE

A Small Craft Advisory is in effect from 7 PM this evening until 1 PM Monday for all ocean zones as well as the Lower Delaware Bay.

North wind around 10 kt will become westerly this afternoon and increase to around 15 kt. Tonight, wind will become northwesterly at 15-20 kt with frequent gusts around 25 kt. Wind will remain northwesterly through the day Monday but is expected to decrease by mid-late afternoon. Seas 1-3 feet through today, increasing to 2-4 feet tonight into Monday afternoon, and then decreasing again by Monday evening.

Outlook...

Monday Night through Tuesday...No marine headlines expected.

Tuesday Night...SCA conditions possible (50%), especially on the ocean waters with wind gusts out of the south/southwest nearing 25 kt and seas 3 to 5 feet.

Wednesday...SCA conditions possible (50%) with seas near 5 feet.

Wednesday Night...SCA conditions expected with wind gusts 25-30 kt.

Thursday through Friday...SCA conditions expected with gales possible (50%) with brisk west/northwest winds 25-35 kt. Seas may near 5 feet at times.

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 7 PM this evening to 1 PM EST Monday for ANZ431-450>455.