textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Updated aviation discussion for 12z TAFs.

KEY MESSAGES

1. Gusty winds behind a cold front are expected for Saturday.

2. Potentially unsettled for next week with multiple days of shower chances.

DISCUSSION

KEY MESSAGE 1...Gusty winds behind a cold front are expected for Saturday.

An area of low pressure is expected to dive through New England tonight, and will drag a cold front through our region overnight. This should be a dry frontal passage though as moisture over our area is lacking, but a noticeable uptick in winds is expected behind the front. The result will be a breezy Saturday across the region.

Wind gusts out of the north/northwest will be strongest after daybreak Saturday. Gusts upward of 25 to 35 MPH with peak gusts around 40 MPH are anticipated. Gusts will gradually diminish by the mid-afternoon and into the early evening.

The one place where gusts could be a bit higher will be over the southern Poconos. The current forecast has gusts getting close to Wind Advisory criteria on Saturday morning but have elected to hold off on any headlines for now. Both the NBM and HREF probability of gusts over 40 kt (Wind Advisory criteria) are around 20-30%. While most of the region will see gusts mainly in the 30s, some areas in the Poconos could get above 40 MPH on Saturday morning.

Outside of gusty winds, it will be a quiet weekend with a dry weather and temperatures a few degrees below normal, but still pleasant as we get towards meteorological summer.

KEY MESSAGE 2...Potentially unsettled for next week with multiple days of shower chances.

An upper level trough will swing in from north to start next week with most guidance having the trough cutoff and form an upper level low. Still some uncertainty though as the GFS has the cutoff low lingering just off the coast while both the ECMWF and CMC have a more progressive pattern. Regardless, some sort of feature will be over our area and result in a stretch of unsettled weather. How long it lasts remains the question that will come into better focus over the next few days.

While the pattern looks unsettled, significant impacts aren't expected at this time. As is the usual case with an upper level low, temperatures look to be below normal for most of next week, but still not too bad as daytime highs should be in the 70s.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

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

Today...VFR. Winds start northwesterly around 5-10 kt but will shift and become west/southwesterly by the afternoon with 10-15 kt sustained winds and gusts 20-25 kt. High confidence in prevailing VFR. Moderate confidence in timing of wind shifts.

Tonight...VFR. A cold front will come through between 04z-08z and result in winds going northwesterly again. Winds will increase in the wake of the front with sustained winds around 15 kt and gusts 20 to 25 kt. Moderate confidence in timing of the frontal passage/wind shifts/wind increases. High confidence in prevailing VFR.

Saturday...VFR. Northwesterly wind gusts between 25 to 35 kt. High confidence.

Outlook...

Saturday Night through Sunday Night...VFR. No significant weather. Saturday night through Sunday night...VFR. No significant weather.

Monday through Tuesday...Primarily VFR. Low chance of showers during the afternoon both days, around 15-30%.

MARINE

Sub-SCA conditions expected for today. Northwest winds will become southwesterly later today, around 10-20 kt with seas 2 to 4 feet.

A Small Craft Advisory is now in effect beginning late tonight for all marine zones as a cold front comes through. This will result in north/northwesterly winds around 20 to 30 kt for late tonight, continuing into tomorrow. Seas will also increase, getting into the 3 to 6 foot range.

The Small Craft Advisory expires on Saturday afternoon for Delaware Bay, but will continue into the first half of Saturday Night for all ocean zones.

Outlook...

Sunday through Tuesday...No marine headlines expected.

Rip Currents...

For today, a northwest wind 10-15 mph will become west and then southwest as more of a sea breeze develops during the afternoon. A medium period 7 to 8 second swell and breaking waves in the surf zone of 1-2 feet are forecast. This will result in a LOW risk for the development of dangerous rip currents for both the New Jersey Shore and Delaware Beaches.

For Saturday, northwest to north winds 15-20 mph with gusts 25-35 mph are forecast. Breaking waves of around 2 to 3 feet in the surf zone along with a medium period 5 to 7 second swell will continue to result in a LOW risk for the development of dangerous rip currents for both the New Jersey Shore and Delaware Beaches.

Ocean water temperatures are in the 50s to low 60s. These chilly water temperatures can quickly cause hypothermia and physical incapacitation to anyone suddenly immersed in the water.

For specific beach forecasts, visit weather.gov/beach/phi

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 4 AM to 4 PM EDT Saturday for ANZ430- 431. Small Craft Advisory from 1 AM Saturday to 2 AM EDT Sunday for ANZ450>452. Small Craft Advisory from 4 AM to 11 PM EDT Saturday for ANZ453>455.