textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

There is increasing concern for very windy conditions in the Southern Poconos where a wind advisory has been issued through 2 PM this afternoon.

KEY MESSAGES

1. Gusty winds behind a dry cold front expected Saturday.

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

DISCUSSION

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

As of midnight, the expected cold front was just starting to enter northern PA. It should be entering the southern Poconos within the next few hours. As expected, radar trends are on the decrease, so don't expect much more than sprinkles. There will be a noticeable uptick in winds is expected behind the front. The result will be a breezy Saturday across the region.

Upstream observations had wind gusts up to 45 mph. Part of that was related to enhanced mixing with the showers moving through. However, that was observed even at locations at a lower elevation than the ridges of Carbon and Monroe County. Given that, the model soundings depicting the mixed layer extending up to 40kt winds aloft, and the still relatively high NBM and HREF probabilities for 40 kt gusts, have issued a wind advisory for these two counties through 18Z/2 PM EDT. It will likely be a case where locations along the ridges (and other more exposed locations) will reach wind advisory criteria, while valley locations may be just shy of wind advisory criteria.

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.

Outside of gusty winds, the weather this weekend shouldn't be impactful with 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.

In general, upper-level troughing will remain in place over much of the Northeastern US through early next week. By mid- week, an upper- low is expected to begin to close off, before tracking slowly northeastward away from the coast. At the surface, a weak cold front is expected to pass through the region on Monday. A surface low will likely form in association with the closed upper-low off the coast as it pulls away.

The first chance for showers and perhaps a storm or two will be on Monday with the passage of the weak front. Chances will be greatest across the eastern half or so of the area, currently ranging from 20- 40%. No significant impacts are expected. Tuesday and beyond, the pattern looks to remain unsettled, though there are discrepancies in guidance as to how close to the coast the low will get due in part to strong high pressure building in from the northwest. Regardless, a 20-40% chance of showers exists over much of the area through Wednesday before the low begins to pull away on Thursday, with high pressure settling in thereafter.

Temperatures through Wednesday look to be fairly close to seasonal norms across the area, with highs generally in the mid 70s and lows in the mid 50s. A warming trend may begin Thursday into Friday.

AVIATION /04Z SATURDAY THROUGH WEDNESDAY/

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

Tonight...VFR. A cold front will come through between 04z-08z and result in winds going Northwesterly again. A few sprinkles at KABE/KTTN are possible. 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 30 kt, shifting to North by mid afternoon and easing to gusts around 20 kt. High confidence.

Outlook...

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

Monday through Wednesday...Primarily VFR. There will be a slight chance of a few periods of sub-VFR conditions each day with a few rain showers and perhaps a thunderstorm.

MARINE

Sub-SCA conditions through this evening, but a Small Craft Advisory will begin 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...

Saturday night...Lingering SCA conditions expected into the overnight hours. Winds under 25 kt, however, lingering seas of Seas 3-6 feet will continue into the overnight hours before diminishing by daybreak Sunday.

Sunday through Monday night...No marine headlines currently anticipated with winds under 25 kt and seas under 5 feet.

Tuesday through Wednesday...SCA conditions possible. Winds under 25 kt, but seas increase to 3-5 feet.

Rip Currents...

For Saturday, north winds around 15-25 mph with localized higher gusts possible. Breaking waves around 2-3 feet in the surf zone with a period around 6 to 8 seconds. In addition, the Full Moon Phase will occur on Sunday. As a result of these conditions, have opted to upgrade to a MODERATE risk for the development of dangerous rip currents for both the Jersey Shore and Delaware Beaches.

For Sunday, northwest winds in the morning will become southwest in the afternoon around 5-10 mph. Breaking waves heights around 1-3 feet in the surf zone. The Full Moon phase will occur on Sunday. Due to lighter winds and lower breaking wave heights despite the Full Moon, have opted to go with a LOW risk for the development of dangerous rip currents for all 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...Wind Advisory until 2 PM EDT this afternoon for PAZ054-055. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 4 AM early this morning to 4 PM EDT this afternoon for ANZ430-431. Small Craft Advisory until 2 AM EDT Sunday for ANZ450>452. Small Craft Advisory from 4 AM early this morning to 11 PM EDT this evening for ANZ453>455.