textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

All sections updated.

KEY MESSAGES

1. A cold front crosses the area overnight with showers.

2. A series of cold fronts and low pressure systems will bring unsettled weather to the area starting Saturday night and continuing through at least Tuesday. Heavy rain from time to time is possible.

DISCUSSION

A cold front crosses the area overnight with showers.

The latest surface map shows a weak area of low pressure across New York State and a cold front into Pennsylvania. A mild and increasingly flow ahead of these features has brought some showers to parts of the region so far today. More showers and possibly a tstm will continue to develop across PA/MD and move east into NJ/DE this evening and into the overnight. We'll continue with the higher CHANCE and low-end LIKELY pops for these time periods. Rains will end by dawn but some patchy rural fog is possible.

While severe weather is not expected, there will likely be some short period downpours this evening with some rainfall rates around an inch per hour possible. The moderately fast motion of the cells will preclude any significant totals however. Average rainfall of 0.1 to 0.3 inches possible with a few totals closer to 1.0 inch possible.

KEY MESSAGE 2... A series of cold fronts and low pressure systems will bring unsettled weather to the area starting Saturday night and continuing through at least Tuesday. Heavy rain from time to time is possible.

High pressure will be centered over the Province of Quebec Saturday morning, and then the center of the high will shift towards the Canadian Maritimes and the Gulf of Maine by Saturday evening. Overall, conditions should start out mostly sunny Saturday morning, then mid and high clouds will build into the region throughout the day. Mild and pleasant otherwise with highs in the 70s to near 80.

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.

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. A cold front passes through the region behind the departing low, and that front will sag south towards Delmarva by Monday morning, where it will stall out.

WPC has a Marginal risk for Excessive Rainfall (1 out of 4) for the region Sunday and 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 will mostly be capped at 30 to 50 percent (chance).

AVIATION /20Z THURSDAY THROUGH TUESDAY/

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

Tonight... Restrictions mostly MVFR in showers and possibly a few tstms (greater chances for tstms across KACY/KMIV). Primarily VFR between the showers. Patchy fog possible late with MVFR possible then too. South to Southwest winds 5 to 10 knots becoming NW by dawn. Medium confid.

Friday... VFR expected. Decreasing clouds early then mostly sunny expected. North winds increasing to 10 to 15 kts with gusts to 20 kts. Medium/high confid.

Outlook...

Friday night through Saturday...VFR. NSW.

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

MARINE

No significant marine headlines for tonight or Friday. Scattered showers or perhaps a TSTM this evening into the early overnight period. Local higher winds in VCNTY of TSTMs.

Outlook...

Friday night through Monday...Sub-SCA conditions through Sunday. SCA headlines may be needed on Monday for east to northeast winds 15 to 20 kt with gusts up to 25 kt and 4 to 6 ft.

VSBY restrictions in showers and isolated thunderstorms Sunday through Monday.

Rip Currents...

Friday...North winds 10 to 15 mph with breaking waves of 1 to 2 feet with a light southerly swell with a 4 to 6 second period. As a result, there is a LOW risk for the development of dangerous and life threatening rip currents for the Jersey Shore and Delaware Beaches.

Saturday...East winds 10 to 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.

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

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...None.