textproduct: Philadelphia/Mt Holly

SYNOPSIS

Strong low pressure across the Great Lakes will slowly move across southern Canada tonight and Thursday. An attached cold front will cross the Middle Atlantic tonight. Strong high pressure builds towards the region Friday and Saturday. Another low and front arrive for Sunday and into Monday. Another storm may affect the area towards midweek.

NEAR TERM /THROUGH TONIGHT/

A warm front is trying to move through this morning. It has not had much problem moving through New Jersey, but with some cold air damming in place west of the Fall Line, it is struggling to move through of the Lehigh Valley and Poconos. As a result, fog, some of it dense, has developed. A Dense Fog Advisory is in effect for Berks/Lehigh/Northampton/Carbon/Monroe as visibility as low as a quarter of a mile has been observed. The Dense Fog Advisory goes until 10 AM, but it may be able to be canceled early depending on how quickly the warm front goes through.

Elsewhere, a another round of showers and isolated embedded thunderstorms are moving through Delmarva and South Jersey as a shortwave clips the southern portion of our area. Not expecting much in terms of impacts from this, and this round of rain should be offshore by the mid to late morning.

For today, the area will be fully in the warm sector ahead of a main cold front passing later this evening. This will allow temperatures to climb into the mid to upper 60s. Our climate sites should not threaten any records though with forecasted highs around 3 to 6 degrees below the daily records. It will be primarily dry for most of the day, though cannot rule out a light shower across the area until the front arrives. Some breaks of sun may actually come over the southern half of the area as well. More widespread showers and scattered downpours will move through later this afternoon as the cold front comes through between 5 PM and 10 PM. The front comes through and shower chances fall off with skies clearing out as well.

For tonight, skies will be partly cloudy with winds picking up in the wake of the front. Gusts will be around 25 to 35 MPH, with peak gusts upward of 40 MPH. Temperatures drop into the low to mid 30s, with upper 20s in the Poconos.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/

Strong high pressure builds towards the area through Friday. Low pressure exits east out of Canada tonight and Friday. The strong pressure gradient between the departing low and high will result in gusty winds across the region both Thursday and Friday. Gusts Thursday will be around 30 mph at times and the gusts will be 30 to 40 mph for Friday. Wind advisory flags are possible. The drier air will result in little or no precipitation thru the period. A couple snow showers across the southern Poconos are not out of the question Friday.

Temperatures will be below normal Thu/Fri with the colder air from Canada remaining across the region. Highs Thu/Fri will mostly be in the 40s with some 30s for the southern Poconos. Lows will range between 25 and 30 degrees both Thu/Fri nights. Winds will create wind chills in the 30s Thu/Fri and in the teens Thu night.

LONG TERM /SATURDAY THROUGH TUESDAY/

High pressure will be affecting the area Saturday with dry weather and temperatures below normal. High temps Saturday will be in the low/mid 40s for most spots after early morning lows in the 20s. These temps are 8 to 10 degrees below normal for late November.

Milder temps arrive for Sunday and continue into Monday too. Readings will just be a few degrees above normal with highs in the upper 40s to low 50s both days. The milder readings do come with a higher chance for rains. We'll continue with slight chances (20%) for Sunday and then have chance pops for Sunday night and Monday. These rains are the result of low pressure and its associated fronts moving across the region.

Beyond that, there are signs that a secondary low may affect the area towards the end of the long term. Chilly air will already have arrived behind the earlier disturbance so temps will already be running a bit below Tuesday. We will closely follow the NBM for Monday night/Tuesday attm.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

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

Today....LIFR/IFR through the morning, improving to MVFR and quickly up to VFR by the early to mid afternoon. The South Jersey terminals have been MVFR/VFR for the past few hours but should come down to IFR especially once rainfall moves out. Moderate confidence in timing and extent of restrictions. Winds southwest around 5-10 kt.

Tonight...VFR. Gusty westerly winds pick up with the passage of a cold front with 10-20 kt sustained and 20-30 kt gusts between 23z and 01z. High confidence in prevailing VFR. Moderate confidence in timing of frontal passage.

Outlook...

Thursday thru Saturday... VFR. Gusty winds Thu./Fri.

Sunday... sub-VFR possible with clouds and rain arriving.

MARINE

A Small Craft Advisory is in effect for the ocean zones today as seas will be around 4 to 6 feet. No marine headlines on Delaware Bay today. Winds will be out of the southwest around 10-15 kt today.

For tonight, an SCA is in effect for all marine zones. A cold front will pass with winds ramping up behind the front. Westerly winds after 00z will be around 15-25 kt with gusts around 30 kt. Seas 4 to 6 feet.

Outlook...

Thursday, Small Craft Advisories continue with West winds around 25 kts and gusts 30 to 35 kts. Fair weather.

Thursday night/Friday... Gale Watch continues with strengthening winds and gusts 35 to 40 kts possible. Fair.

Friday night/Sat... Lowering winds and seas thru the period with sub-SCA by Saturday morning. Fair weather.

PHI WATCHES/WARNINGS/ADVISORIES

PA...Dense Fog Advisory until 10 AM EST this morning for PAZ054-055- 060>062. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 7 PM this evening to 6 PM EST Thursday for ANZ430-431. Gale Watch from Thursday evening through Friday afternoon for ANZ430-431-450>455. Small Craft Advisory until 6 PM EST Thursday for ANZ450>455.