textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

The aviation and rip current sections have been updated.

KEY MESSAGES

1. High pressure keeps the area dry through the end of the week.

2. Late this weekend into early next week, a trough will bring cooler weather and a chance for rain.

DISCUSSION

KEY MESSAGE 1... High pressure keeps the area dry through the end of the week.

Fair weather expected tonight and seasonably cool temperatures are forecast. On Wednesday, the upper-level trough that was across our area today will have amplified and sunk southward. The base of the trough is expected to close off into an upper low with the most recent guidance showing that occurring near the North Carolina coast. After it deepen a bit, it will then slowly move off to the northeast. At the surface, a low pressure system will likely form in association with the closed upper low. We will be close to this system, but in general high pressure will prevail across Delmarva, PA and NJ. As a result, the forecast continues to remain dry through the end of the week. The pleasant weather will continue into early Saturday too, but then some scattered showers or a tstm are possible for the afternoon hours for the NW counties.

A gradual warming trend will take place this week with temperatures reaching into the low 90s for both Friday and Saturday. Shore areas and the southern Poconos may see highs in the mid/upper 80s.

KEY MESSAGE 2... Late this weekend into early next week, a trough will bring cooler weather and a chance for rain.

The previously mentioned high pressure system during the later half of the week should weaken during the later half of the weekend as a positively tilted upper level trough digs in from the northwest. At the surface, a low should develop in response. There are differences between the deterministic guidance as to if this will be a closed surface low or a trough, but regardless, the net effect appears to be a cooling trend, especially going into Monday.

As can be expected with the wide variety of surface pattern solutions, there is also considerable uncertainty as to if this will result in widespread rain for the area. While it doesn't look like an ideal pattern for widespread, significant precipitation (moisture advection isn't likely to be maximized), given the synoptic scale lift, rain chances of 30 to 60 percent at this point seem appropriate for the pattern.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

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

Tonight...VFR expected. A north to north-northwest wind at 5 knots or less with periods of light and variable at times. High confidence.

Wednesday...VFR with a mainly clear sky. A north to north- northeast wind around 5 knots. Winds turn more east to southeast at KMIV/KACY during the afternoon due to a sea breeze. High confidence.

Outlook...

Thursday thru Saturday morning...VFR expected.

Saturday afternoon...Mainly VFR. A slight chance for a shower or thunderstorm at KRDG/KABE.

MARINE

High pressure builds in tonight and remain for the midweek period. Winds look to remain onshore with gusts 15 to 20 kts much of the rest of the afternoon. Fair weather.

Tonight and Wednesday... Fair weather and sub-SCA conditions continue.

Outlook...

Looks to be a great period on the waters with high pressure prevailing across the region. Winds and seas will remain below SCA levels for the rest of the week and into the early part of the weekend. Fair weather through Saturday then slow increasing chances for a few showers or a TSTM Saturday evening thought Sunday.

Rip Currents...

On Wednesday, north winds 5 to 10 mph in the morning will turn to the east, then southeast late in the day behind sea breezes. Breaking waves will be 2 to 3 feet. There will be a lessening easterly swell with a 9 to 10 second period. As a result, there is a LOW risk for the development of dangerous and life threatening rip currents for the Jersey Shore for Monmouth county, Ocean county, and Atlantic county, and a MODERATE risk for the Jersey Shore for Cape May county and Delaware Beaches.

On Thursday, winds will turn southerly and seas/swells will continue to lessen. Thus, there is a LOW risk of rip currents for the New Jersey Shore 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.