textproduct: Philadelphia/Mt Holly

SYNOPSIS

High pressure will remain in control across the area through tonight. 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. Another high pressure system will build in to end the week and for the start of the weekend.

NEAR TERM /THROUGH TONIGHT/

High pressure is currently moving overhead and offshore. Low pressure developing over the Southern Plains will lift to the north and east tonight through Tuesday morning. A warm front extending from that low will lift north into the region Tuesday afternoon.

In terms of sensible weather, high clouds continue to move into the region tonight. Clouds will thicken and lower throughout the day Tuesday as that warm front gets closer. Conditions will be dry for most of the period with some rain moving in from the west starting around midday Tuesday before spreading east late Tuesday afternoon.

Winds become mostly light and variable tonight, then a light southerly flow develops on Tuesday both behind the departing high and ahead of the approaching warm front.

Lows tonight will generally range from the low to mid 30s for most of the area, though lows will be in the mid and upper 30s in the urban areas, Delmarva, and along the coasts. A mild day on tap for Tuesday with highs in the low to mid 50s north and west of the Fall Line and in the upper 50s to low 60s across southern New Jersey and Delmarva. Depending on how far north that warm front can get on Tuesday will determine how warm it gets and how far north that warmth spreads.

SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/

A weak warm front will move through Tuesday night with more stratiform rain moving through the area. This warm front will allow for warmer air to filter in overnight and into Wednesday. Lows Tuesday night are in the mid 40s to mid 50s. Highs on Wednesday are in the 60s for most.

During the day Wednesday, a cold front will be approaching the area from the west. The coverage of the precip looks more in the form of rain showers as the general trend has been a bit more convective. There is also the potential for an isolated thunderstorm with some instability present. Best potential for a rumble of thunder looks to be in Delmarva and southern NJ. We trend drier Wednesday night with just some lingering showers that taper off as the cold front passes through. Rainfall totals look to be between 0.25-0.50" with localized higher amounts. Once the cold front passes, we see strong cold air advection and winds increasing out of the west. Wind gusts will start to increase to 25-35 mph across the area. Lows Wednesday night will be in the upper 20s to upper 30s. Wind chill values will be in the 20s and potentially the teens in the Poconos.

LONG TERM /THURSDAY THROUGH MONDAY/

Winds continue to increase for Thursday and Friday with cold air continuing to filter in. For Thanksgiving, the day looks dry but cold and windy. Highs are in the mid 30s to mid 40s. Gusty winds out of the west at 30-35 mph. Lows Thursday night are in the 20s. Wind chills will be in teens when you factor in the windy conditions.

Friday looks to be the windiest day with gusts out of the west- northwest at 30-40 mph. In this set-up, with all the cold air filtering in across the region, there will be ongoing lake-effect snow showers upstream of our area. Due to the wind shift of a more NW component, we have the potential to see some snow showers in the Poconos and northern NJ on Friday. Highs on Friday are in the mid 30s to mid 40s. Lows Friday night are in the 20s. Wind chill values are in the teens again. Our winds do decrease Friday night as a surface high builds in and moves overhead into Saturday. This will keep us dry Friday night into Saturday.

For the weekend, it is a colder start with highs on Saturday in the mid 30s to low 40s. By Sunday, temperatures start to climb back into the mid 40s to mid 50s for highs. There is also the signal for another system to bring increasing precipitation chances on Sunday.

AVIATION /06Z TUESDAY THROUGH SATURDAY/

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

Through 12z...VFR. Winds light/variable to calm, favoring a southerly direction if anything.

Today...VFR through most of the day before rain moves in later this afternoon. Cloud bases gradually lower as the day goes on. Rain moves into the Lehigh Valley around 18z-19z, the I-95 corridor around 20z-21z, and 21z-22z for the South Jersey terminals with lower CIGs and VSBYs occurring not much longer after light rain begins. Thinking MVFR restrictions begin around 21z-22z for KRDG/KABE, 22z-01z for the I-95 corridor terminals, and 00z-03z for the South Jersey terminals. Winds pick up around 14z-15z, with a light south/southeasterly wind around 5-10 kt. High confidence in prevailing VFR through at least the early afternoon, with moderate confidence in timing and extent of restrictions.

Tonight...MVFR to start with IFR CIGs and possibly VSBYs moving in as rain continues through the night. Expecting IFR conditions to take over at the Lehigh Valley and I-95 terminals between 00z-03z. KACY/KMIV may stay MVFR depending on the positioning of the warm front. Winds start out of the south/southeast but will transition to the southwest between 04z-07z, around 5-10 kt. A brisk low-level jet will result in a period of low-level wind shear between 00z-06z. Low confidence overall.

Outlook...

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

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

Saturday...VFR. West-northwest winds 5-10 knots.

MARINE

Light and variable winds tonight, then S 5 to 10 kt late tonight and Tuesday morning, increasing to 10 to 15 kt with gusts up to 20 kt late in the day. Seas 1 to 2 feet, building to 2 to 4 feet late Tuesday.

Outlook...

Tuesday night...A Small Craft Advisory has been issued for all of the ocean zones for gusts of 25 knots out of the south with seas near 5 feet.

Wednesday...SCA conditions possible with wind gusts of 20-25 knots and seas near 5 feet.

Wednesday night through Thursday...SCA conditions are expected with a west-northwest wind 20-30 kt and seas 4-6 feet.

Thursday night through Friday night. Gales expected with a west- northwest wind of 35-40 kt and seas of 4-6 feet.

Saturday...SCA conditions possible early but winds and seas quickly subsided through the day.

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 6 PM this evening to 6 AM EST Wednesday for ANZ450>455.