textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Updated Aviation section with 00Z TAF cycle.

KEY MESSAGES

1. Tranquil conditions are anticipated through the daytime hours Saturday as high pressure centered north of the region slides slowly eastward.

2. A series of cold fronts and low pressure systems will keep unsettled weather over the area from Saturday night through Thursday. Heavy rain is possible Sunday and Sunday night.

DISCUSSION

KEY MESSAGE 1...Tranquil conditions are anticipated through the daytime hours Saturday as high pressure centered north of the region slides slowly eastward.

Mid-level ridging over portions of the Gulf Coast region will continue to shift slowly southwestward, with northwesterly flow aloft increasing across the area tonight through Saturday. At the surface, High pressure currently centered over portions of Ontario will shift eastward through Saturday, passing north of the region on Saturday before shifting offshore.

Tonight, low temperatures will range from near 50 across portions of eastern PA and northern NJ to the mid 60s across portions of Delmarva as a cooler airmass starts to settle into the region. It should remain dry through the daytime hours Saturday, though some clouds will remain around. It should be notably cooler however, with high temperatures generally in the low to mid 70s.

KEY MESSAGE 2...A series of cold fronts and low pressure systems will keep unsettled weather over the area from Saturday night through Thursday. Heavy rain is possible Sunday and Sunday night.

High pressure moves out to sea Saturday night, and then low pressure organizes and develops over the Midwest. A warm front extending out from that low will lift north through the Northeast Saturday night through Sunday morning. Showers first develop after midnight Saturday night and continue through Sunday morning. A warm and dry afternoon is in store with some clouds around. Temperatures have warmed into the 70s to near 80 across the area, with a few more degrees of warming anticipated through this afternoon. As low pressure draws nearer to the region, southerly flow increases throughout the Northeast and low level moisture increases as well with surface dew points rising well into the 60s and low 70s and PWATs will be in excess of 2 inches. Low pressure then passes through the southern Poconos and Lehigh Valley Sunday afternoon and evening, resulting in more widespread showers with isolated thunderstorms across most of the area during that time. Locally heavy rain may develop from time to time. As that low passes through the region, a cold front will sag south through the region Sunday night, and the axis of heavy rain will then track south towards the I-95 corridor and into the Philadelphia area. The front will stall out over Delmarva Monday morning.

WPC continues the Slight Risk for Excessive Rainfall (2 out of 4) for Sunday and Sunday night for areas along the I-95 corridor and points north and west. A Marginal Risk remains for the rest of the region south and east of the I-95 corridor. A Marginal Risk also continues for the entire region into Monday.

Several more disturbances will pass through the region Monday and Tuesday, and this will keep rain chances in the forecast during this time. For now, PoPs are limited to 30 to 50 percent (chance) given the uncertainty of the timing and coverage of showers. Low pressure looks to develop over the Mid-Atlantic coast and will meander over the western Atlantic between the Jersey Shore and south of Long Island during the midweek period. Onshore flow and unsettled weather continues with below normal temperatures.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

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

Tonight...VFR. North-northeast winds of 5-10 kt. High confidence.

Saturday...VFR. Northeast winds in the morning of 5-10 kt will shift more easterly in the afternoon. High confidence.

Outlook...

Saturday night through Monday...Sub-VFR from time to time in SHRA, isolated TSRA (mainly Sunday afternoon and Sunday night), low stratus, and fog.

Tuesday through Wednesday...Sub-VFR conditions possible with showers around with breezy northeast winds.

MARINE

A Small Craft Advisory has been issued for NJ Atlantic coastal waters north of Great Egg Inlet from 4 AM to 2 PM Saturday. Northeast winds will increase to 15-20 kt with gusts near 25 kt overnight tonight, with seas increasing to near 5 feet. Winds will shift to east-northeast on Saturday and slowly diminish, with diminishing seas as well. Outside of the advisory area, winds are expected to remain below 25 kt with seas remaining below 5 feet.

Outlook...

Saturday night through Sunday...Sub-SCA conditions. VSBY restrictions in showers and isolated thunderstorms Sunday afternoon and Sunday night.

Monday through Wednesday...SCA headlines may be needed starting on Monday for east to northeast winds 15 to 20 kt with gusts up to 25 kt and 4 to 6 ft. Gale force winds are possible Tuesday with wind gusts exceeding 35 kts. Seas may build as high as 10 to 15 ft from Tuesday through Thursday.

VSBY restrictions in showers Monday through Wednesday.

Rip Currents...

Saturday...East winds around 15 mph with gusts up to 20 mph. Easterly swells with a 10 to 12 second period. As a result, there is a MODERATE risk for the development of dangerous and life threatening rip currents for Monmouth county and Ocean county shores and a LOW risk for Atlantic county and coastal Cape May county shores and Delaware Beaches.

Sunday...The winds shift to south/southeast but remain around 15 to 20 mph. Breaking wave heights in the surf zone look to be around 3 to 4 feet for the Jersey shore and 2 to 3 feet for the Delaware Beaches. We will go with a MODERATE risk of dangerous and life threatening rip currents for the Jersey shore where there's more of a onshore component to the wind with a LOW risk for the Delaware Beaches.

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 2 PM EDT Saturday for ANZ450>452.