textproduct: Philadelphia/Mt Holly

SYNOPSIS

High pressure will remain in control across the area through Monday night. Low pressure will begin to approach from the west on Tuesday, bringing the start of unsettled weather. The low and associated cold front will pass through Wednesday, with a few reinforcing shots of cold air thereafter. High pressure will build back in to end the week.

NEAR TERM /THROUGH TONIGHT/

It is quiet this morning as a cold front moves out and high pressure builds in. With a bit of a gradient in place when we mix out, a brief period of wind gusts near 15-25 MPH could come later this morning, but winds should settle by the early afternoon as the incoming high gets closer. Skies will be mostly sunny today, with clouds increasing late day ahead of the next system. Temperatures should get into the low to mid 50s, with 40s in the higher elevations of the Poconos and NW NJ.

For tonight, high pressure will move overhead and offshore. This will result in a period of calm winds overnight but with the mid-week system approaching, cloud cover will continue to increase. This will prevent temperatures from bottoming out completely. Lows get down into the low to mid 30s.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/

High pressure will depart to the east through the day Tuesday with a low pressure system approaching from the west. A weak warm front will move through Tuesday night.

Tuesday is expected to feature overcast skies with rain chances increasing from west to east during the afternoon hours. High temperatures look to be in the low 50s northwest of I-95 and in the upper 50s to near 60 southeast. Rain will be widespread across the area Tuesday night. With warm advection through the night, lows should be in the mid 40s across most of eastern PA and northern NJ, and in the low 50s for the Delmarva and southern NJ.

A cold front will approach the region during the day Wednesday. Ahead of the cold front, scattered showers will remain possible areawide. PoPs will be in the 30-50% chance during the day Wednesday. Wednesday afternoon and evening, models are hinting at some modest elevated instability, so a few rumbles of thunder cannot be ruled out. This currently appears most likely across the Delmarva and southern NJ. With the region ahead of the cold front and amidst continued warm advection, Wednesday will be relatively warm across the entire area, with highs generally in the 60s.

The cold front will move through the region Wednesday evening into Wednesday night, ending rain chances. By the time all is said and done, rainfall amounts across the area are expected to be in the 0.25-0.50" range, with isolated higher amounts possible.

Behind the cold front, strong cold air advection will bring much colder temperatures to the area. Lows Wednesday night look to be in the low-mid 30s areawide. In addition, gusty northwest winds are expected, with gusts perhaps exceeding 30 mph. This will lead to windchill values falling into the 20s, and potentially the teens across the Poconos.

LONG TERM /THURSDAY THROUGH SUNDAY/

Strong northwesterly flow and cold air advection will continue Thursday and Friday. It appears that both days will be several degrees below average, with most locations remaining in the 40s for highs and 20s for lows. Both days will be breezy, with northwesterly wind and gusts potentially in the 30-40 mph range. Aside from being brisk, it currently appears that the area will remain dry. With that said, these northwest flow regimes favor the development of lake effect snow, and we will have to monitor to see if some of that activity can make it far enough southeast to reach the higher elevations of eastern PA and far northern NJ.

As high pressure begins to build in Friday night and into the weekend, winds will relax, but it will stay several degrees above average. By Sunday, temperatures may begin to rebound a bit. Significant model discrepancies exist, which is to be expected at this range, but our next storm system of interest could bring increasing precipitation chances to end the weekend.

AVIATION /12Z MONDAY THROUGH FRIDAY/

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

Today...VFR. NW winds 10 to 15 kt with sporadic gusts up to 20 kt in the morning, becoming W/WSW around 5 to 8 kt in the afternoon. High confidence.

Tonight...VFR. Winds light and variable/calm. High confidence.

Outlook...

Tuesday through Wednesday...Periods of sub-VFR conditions are expected in rain.

Wednesday night through Friday...VFR. Gusty northwest winds, especially Thursday and Friday.

MARINE

A Small Craft Advisory is in place through 18z for coastal waters north of Little Egg Inlet as wind gusts could get near 25 kt at times. No marine headlines on the rest of the waters.

Once the SCA expires, sub-SCA conditions are expected through tonight. Winds will be less than 10 kt with seas 1 to 2 feet.

Outlook...

Tuesday...No marine headlines are anticipated. Winds below 25 kt and seas below 5 feet.

Tuesday night through Wednesday...SCA conditions are possible (40- 50%) on the ocean waters with south wind increasing to 15-25 kt. Seas could potentially reach 5 feet.

Wednesday night through Friday...SCA conditions are expected, with gales possible (40-50%). Northwest wind 20-30 kt, potentially near 35 kt, particularly Thursday afternoon into Friday. Seas below 4-6 feet.

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory until 1 PM EST this afternoon for ANZ450- 451.