textproduct: Philadelphia/Mt Holly

SYNOPSIS

High pressure builds in from the west tonight. The center of the arctic high slides to our south Tuesday before weakening as it shifts offshore Wednesday. A warm front may slide by to our north Wednesday into Thursday, followed by a cold front Thursday night. High pressure returns to close out the week.

NEAR TERM /THROUGH MONDAY/

The cold front and low pressure which brought the area a widespread snowfall this morning continues to depart as strong, Arctic high pressure builds over the central CONUS. As a result of a tightening pressure gradient between these features, winds have been quite breezy with gusts generally ranging between 30-40 mph as cold air advection pours into the region. Temperatures have also topped out earlier this morning, and continue to fall this afternoon under a mix of sun and clouds. A few residual snow showers and flurries are possible, but will diminish toward sunset.

Tonight, the pressure gradient will lessen to an extent, but winds will remain breezy with gusts up to 20-30 mph continuing. Skies will become mostly clear as well. Low temperatures are expected to fall into the low to mid teens in many locales, with single digits across the higher terrain in the Poconos and northern New Jersey. When factoring the wind into the equation, wind chills will range generally between 0 to 5 degrees above zero. The exception will be in the Poconos where wind chills will be well into the negatives, as cold as -15 degrees. Have decided on issuing a Cold Weather Advisory for the Pocono Plateau as wind chills are already close to advisory threshold and it appears that criteria will be met overnight.

On Monday, surface high pressure shifts off to the south and east and settles over the Southeast US with a weak surface trough nearby. An impulse will also be tracking through in the upper levels, which will bring an increase in cloudiness through the day. With enhanced lift between the trough and the energy aloft, this may result in a few snow showers developing, mainly across areas northwest of the I-95 corridor. Any accumulations would be negligible with perhaps up to a coating in the higher terrain. Winds will continue to diminish with gusts up to 25 mph possible. As a result of recent snow pack and cloud cover, suspect temperatures will struggle to reach the freezing mark on Monday. For many highs will top out in the mid 20s to low 30s with wind chills in the teens and 20s.

SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/

Monday night is another cold night with temperatures in the teens for many. Winds will be lower Monday night at around 10-15 mph which results in wind chill values in the single digits to low teens for most. For Tuesday, it is a dry day with the high pressure system in place across the region. Highs on Tuesday are in the mid 20s to mid 30s.

By Tuesday night, temperatures are slightly higher with overnight lows in the 20s for most and teens for the higher elevations. Winds are at around 5-10 mph, so wind chill values are in the teens and low 20s for most.

Our weather pattern starts to change by Wednesday which results in more mild air filtering in. Our high pressure system starts to move offshore Wednesday which gives us more of a southwest wind that ushers in warmer air. Highs on Wednesday are mainly in the upper 30s to upper 40s.

LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/

A more amplified pattern looks to take shape for the end of the week. A low pressure system near the Great Lakes region Thursday moves northeast into Quebec Friday. This low pressure system will drag a cold front through the area Thursday night. The precipitation type with this cold front will be rain as temperatures will be mainly in the mid 40s to mid 50s on Thursday and mainly upper 30s to mid 40s Thursday night. By Friday, a high pressure system builds in from the west and temperatures are in the 40s for most. This high pressure system moves closer to the region Saturday which may keep us completely dry. However, there is a low pressure system near the Great Lakes region and its associated warm front extending close to the area during this timeframe that may have the potential to initiate some precipitation. Due to the uncertainty, PoPs are capped at a slight chance for Saturday.

AVIATION /21Z SUNDAY THROUGH FRIDAY/

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

Rest of Today (through 23Z): Primarily VFR, lingering MVFR ceilings possible at KACY. Northwest winds around 15-20 kt with occasional gusts up to 30-35 kt at times. This may result in periods of blowing snow which could reduce visibility at some terminals. Moderate confidence overall.

Tonight...VFR with mostly clear skies. West-northwest winds around 10-15 kt with gusts up to 20-25 kt. High confidence.

Monday...VFR with increasing clouds. West-northwest winds around 10 kt with gusts up to 20 kt. A slight chance of a snow shower at KABE and KRDG. High confidence.

Outlook...

Monday night through Wednesday night...VFR. No significant weather.

Thursday...Primarily VFR. A slight chance of rain showers in the afternoon.

MARINE

Gale Warnings for all Atlantic Coastal Waters and the Delaware Bay are in effect through 7 AM Monday.

Northwest winds between 25-35 kt with gusts up to 40 kt are expected to continue through tonight and seas of 4-7 feet. Areas of freezing spray are likely.

For Monday, west-northwest winds will diminish to around 15-25 kt with gusts up to 30 kt possible and seas of 3-5 feet. Spotty areas of freezing spray may continue.

Outlook...

Monday night through Tuesday night...No marine headlines are currently anticipated with winds remaining below 25 kt and seas below 5 feet.

Wednesday...Small Craft Advisory conditions possible with southwesterly winds 15-20 kt with gusts perhaps near 25 kt. Seas 2-4 feet.

Wednesday night...No marine headlines are currently anticipated with winds remaining below 25 kt and seas below 5 feet.

Thursday...Small Craft Advisory conditions possible with south- southeasterly winds 15-20 kt with gusts perhaps near 25 kt. Seas 4-6 feet.

PHI WATCHES/WARNINGS/ADVISORIES

PA...Cold Weather Advisory from 9 PM this evening to 9 AM EST Monday for PAZ054-055. NJ...None. DE...None. MD...None. MARINE...Gale Warning until 7 AM EST Monday for ANZ430-431-450>455.