textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Updated Rip Current Section for Monday and Tuesday.

KEY MESSAGES

1. A weak cold front will pass through the region tonight into early Monday morning.

2. Monitoring a far offshore low midweek, but high pressure keeps it dry through late week.

DISCUSSION

KEY MESSAGE 1...A weak cold front will pass through the region tonight into early Monday morning.

In general, upper-level troughing will remain in place over much of the Northeastern US through the first half of the week. At the surface, a weak cold front will pass through the region tonight into early Monday morning.

Guidance continues to trend of drier, with maximum rain chances around 20% Monday afternoon, primarily across our southern Delmarva zones. While a few sprinkles or light showers can't be ruled out given the broad troughing aloft and weak frontal passage, most areas will likely remain dry.

Temperatures look to be close to seasonal norms or slightly below, with highs in the mid 70s and lows in the 50s.

KEY MESSAGE 2...Monitoring a far offshore low midweek, but high pressure keeps it dry through late week.

By mid-week, an upper- low is expected to begin to close off near the North Carolina coast before tracking slowly northeastward away from the coast. A surface low will likely form in association with the closed upper-low off the coast as it pulls away.

Guidance seems to be converging on a slower moving cut- off low, but well off the coast. Consensus keeps this low well offshore thanks to a strong ridge of high pressure that will remain squarely in control across the Great Lakes region and into the rest of the Northeast. As a result, it is increasingly likely that the vast majority of land areas will stay dry with this system. Should the surface low drift closer to the eastern seaboard, we could see a northeasterly flow that could help cool temperatures down slightly midweek, especially along the coast, but even so, dry conditions will likely still prevail.

Otherwise, we are expecting seasonable temperatures Tuesday with gradual warming through the end of the week. Friday and Saturday could see temperatures in the afternoon creep back into the low 90s as surface high pressure slips to the Southeastern US and ushering in a much warmer airmass across the Northeast. Some precipitation could be possible by the weekend, but confidence remains low at this time.

AVIATION /20Z SUNDAY THROUGH FRIDAY/

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

Through 00Z...VFR. A few afternoon clouds 6-8 kft. West winds around 10 kt with a few gusts near 20 kt possible. High confidence.

Tonight...VFR with some increase in mid-level clouds. Southwest winds 5 kt or less. High confidence.

Monday...VFR. Winds becoming northeast at 5-10 kt. High confidence.

Outlook...

Monday night through Friday...Primarily VFR.

MARINE

A Small Craft Advisory remains in effect for all NJ and DE Atlantic coastal waters south of Manasquan Inlet NJ until 6 PM for seas near 5 feet at times. While some guidance suggests seas may remain elevated into tonight, the general trend should be downward, so have opted not to extend the Advisories at this time. Southwest winds today of 10-20 kt will become north tonight and northeast on Monday at 10-15 kt. Otherwise, fair weather.

Outlook...

Monday night through Friday...Sub-SCA conditions probable. Continuing to monitor the far offshore low midweek for potential changes to the forecasts for elevated seas.

Rip Currents...

A HIGH RISK FOR THE DEVELOPMENT OF DANGEROUS RIP CURRENTS REMAINS IN EFFECT UNTIL 8 PM TODAY FOR COASTAL OCEAN COUNTY.

For Monday, northeast winds around 5-10 mph in the morning will become east winds and increase to around 10-15 mph in the afternoon. Breaking wave heights will be 2-3 feet accompanied by a 2-3 ft east-northeast swell at 9-10 seconds. As the Full Moon Phase is only one day removed, have opted to keep both the Jersey Shore and Delaware Beaches at a MODERATE risk for the development of dangerous rip currents.

For Tuesday, northeast winds around 10-15 mph in the morning will become southeast winds around 5-10 mph in the afternoon. Breaking wave heights will be 2-3 feet with a east-northeast swell around 8-9 seconds. Given similar conditions to Monday, have opted to continue with a MODERATE risk for the development of dangerous rip currents at all beaches.

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

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...High Risk for Rip Currents until 8 PM EDT this evening for NJZ026. DE...None. MD...None. MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ451>455.