textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Coastal Flood Advisory added for Atlantic and Cape May Counties.

KEY MESSAGES

1. The nor'easter slowly departs the region on Monday.

2. Coastal flooding threat lowered in many areas but still a concern along the back bays of New Jersey and Delaware.

3. A cold front is likely to cross through the region Friday into Saturday.

DISCUSSION

KEY MESSAGE 1...The nor'easter slowly departs the region on Monday.

The nor'easter is now centered just offshore the NJ coast, with high pressure centered to the north. The low will continue to weaken as it tracks slowly northeastward.

Winds have now weakened substantially compared to the past few days, now only around 10 mph or so during the day out of the N to NW. Shower coverage will continue to diminish as well, with the best chance for an isolated to scattered shower north earlier in the day with PoP chances decreasing through the afternoon. Cloud coverage will linger through most of the day, though some breaks in the clouds will be possible late afternoon south and west.

KEY MESSAGE 2... Coastal flooding threat lowered in many areas but still a concern along the back bays of New Jersey and Delaware.

A Coastal Flood Advisory was added for Atlantic and Cape May counties for minor tidal flooding during this morning's high tide. Despite the weak offshore flow, back bays and other tidal waterways are slow to drain and could see minor tidal flooding as a result.

Further north, the onshore flow and continued effects of the Nor'easter will keep high tides Monday morning at Minor flooding levels. For those areas, a Coastal Flood Advisory remains in effect Monday morning. One exception, is Ocean County NJ, where we have kept the Coastal Flood Warning with the effects of high water in the back bays continuing. The warning presently goes until Monday 2 PM, but may need to be extended.

Further south, high water for back bays across Southern Delaware (including Rehoboth Bay, Indian River Bay and Little Assawoman Bay) remain a concern, so a Coastal Flood Warnings for Sussex County Delaware remains in effect until Monday 2 PM.

For Delaware Bay communities, a strengthening Northwest wind will remain across Delaware Bay into tonight. This will promote lowering tidal departures as the waters is pushed down/out Delaware Bay. As a result, additional flooding (at high tides) will be spotty Minor or less. No additional flags for tidal flooding are expected.

For the tidal Delaware River, the North to Northeast flow has kept water levels (at high tide) at the lower part of Minor flooding range. No flags for tidal flooding are expected.

KEY MESSAGE 3...A cold front is likely to cross through the region Friday into Saturday.

The surface high that will be over the region for much of the week will start to build southeast and off shore by Thursday. This will open the door for a cold front to sweep through the region Friday or Saturday. Models for the most part, aren't depicting a widespread rain event with this front. However, southwesterly flow on Wednesday and Thursday, should set the stage with ample moisture in place. The biggest question is forcing with this front. The best synoptic scale lift will likely be well removed from the mesoscale forcing associated with the front. For now the 20 to 30 percent PoPs through this period seem appropriate this far out. Preliminary guidance indicates that temperatures behind the front could be 5 to 10 degrees colder than normal.

AVIATION /07Z MONDAY THROUGH FRIDAY/

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

Rest of tonight...Continued MVFR/IFR conditions in lingering SHRA and BR. North to northeast winds slowly trending towards northwest at around 10 kts, with a few higher gusts remaining possible. Moderate confidence.

Monday...Lingering IFR conditions in the morning should give way to MVFR by the afternoon, with improvement to VFR not out of the question by late afternoon. Northwest winds around 10 kts, decreasing to 5-10 kt during the afternoon. Moderate confidence.

Monday Night...VFR with light and variable winds. Moderate confidence.

Outlook...

Tuesday through Friday...prevailing VFR expected.

MARINE

Small Craft Advisories were allowed to expire or were cancelled with the exception of the nearshore waters of Monmouth and Ocean counties where the SCA continues until 2PM this afternoon.

Seas 3-5 feet. Visibility restrictions in rain and some spray will remain possible into Monday morning.

Outlook...

Tuesday through Friday...winds and seas should stay below SCA criteria.

Rip Currents...

For Monday...Light offshore winds will prevail from the NNW to NW around 10 kts with wave heights around 2-4 feet in the surf zone. A lingering east- northeasterly 2 foot 9 second swell will, however, keep the risk for rip currents elevated. As a result, a Moderate Risk for rip currents is forecast for all area beaches.

For Tuesday...Offshore winds from the WNW diminish to around 5-10 kts with wave heights falling to 2-3 feet in the surf zone. A weak 2 foot 8 second easterly swell lingers. With improving conditions, a Low Risk for rip currents is forecast for all area beaches.

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...Coastal Flood Warning until 2 PM EDT this afternoon for NJZ020- 026. Coastal Flood Advisory until 2 PM EDT this afternoon for NJZ012>014. Coastal Flood Advisory from 8 AM this morning to 2 PM EDT this afternoon for NJZ022>025. DE...Coastal Flood Warning until 2 PM EDT this afternoon for DEZ003- 004. MD...None. MARINE...Small Craft Advisory until 2 PM EDT this afternoon for ANZ450- 451.