textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

The Severe Thunderstorm Watch is no longer in effect.

Wind Advisory in effect for all of the forecast area through 2 am.

Gale Warning in effect until 6 AM early Tuesday morning.

KEY MESSAGES

1. Severe Thunderstorm Watch #71 is no longer in effect. Gusty winds will continue behind the cold front.

2. Some minor coastal flooding along the back bays with high tide this evening.

3. Cold and dry for the middle of the week, then temperatures moderate late this week and through this weekend.

DISCUSSION

KEY MESSAGE 1...Severe Thunderstorm Watch #71 is no longer in effect. Gusty winds will continue behind the cold front.

Thunderstorms have tapered off, and severe weather is no longer expected. Therefore, the Severe Thunderstorm Watch has been cancelled.

Behind the front, a tight west to northwest pressure gradient is developing with winds 25 to 35 mph with 50 to 55 mph gusts. Winds should diminish somewhat going through the overnight hours. The Wind Advisory remains in effect until 2 am.

Much colder air spreads into the region. Lows tonight will drop into the upper 20s and low 30s. Colder and breezy on Tuesday with highs in the upper 30s to low 40s. Though not as windy, it will still be quite breezy on Tuesday.

KEY MESSAGE 2...Some minor coastal flooding along the back bays with high tide this evening.

South winds will continue to increase through this evening with gales developing by or just after sunset. This will keep water from draining out of Barnegat Bay, Rehoboth Bay, and Little Assawoman Bay, resulting in elevated tide levels and some minor coastal flooding around the high tide this evening. The most likely areas to experience impacts will be along the northern end of Barnegat Bay in Ocean County NJ, Rehoboth Bay and Little Assawoman Bay in Sussex County DE. These bays are particularly susecptible to flooding during strong southerly wind events, as the winds prevent water from draining normally during low tide. Thus, impacts may not follow typical astronomical tide cycles. These advisories are in effect through 2 AM Tuesday, however extensions may be needed if impacts linger after winds shift offshore.

The Eastern Shore of Chesapeake Bay and upper portion of the tidal Delaware River (north of Philadelphia) could also experience some minor coastal flooding, though confidence is lower for these areas. Trends will continue to be monitored to determine if any additional advisories may be needed.

KEY MESSAGE 3...Cold and dry for the middle of the week, then temperatures moderate late this week and through this weekend.

Canadian high pressure will be centered over the southern Appalachians and Mid-Atlantic Tuesday night, then will lift to the northeast, with the center of the high passing over New Jersey on Wednesday. The high then lifts into the Canadian Maritimes Wednesday night through Thursday. A weak cold front will pass through the region Thursday night, followed by a stronger cold front Friday night. High pressure will mostly be over the area this weekend until another cold front potentially passes through the area Sunday night.

Temperatures Tuesday night through Wednesday will more resemble that of January than mid-March with lows in the 20s and low 30s and highs in the upper 30s to low 40s. Thereafter, a much warmer airmass begins to build east with highs warming into the 40s and low 50s Thursday, then generally in the low to mid 50s north and west of the Fall Line and in the mid and upper 50s south and east of the Fall Line Friday through Sunday.

With the passage of the first front Thursday night, generally 20 to 30 percent PoPs, mostly for rain, but some spotty freezing rain is possible for the southern Poconos. With the stronger front Friday night, PoPs will generally be in the 30 to 50 percent range, again, mostly rain.

AVIATION /06Z TUESDAY THROUGH SATURDAY/

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

Tonight...The cold front is working its way through the region. TSRA are ending, but sub-VFR conds will continue for several hours until the rain ends. There may even be some SN at KRDG/KABE for a few hours before precipitation ends. W-NW 25 to 35 kt with gusts as high as 45 kt, diminishing to around 20 kt with gusts up to 30 kt mainly after 06Z. Moderate confidence overall.

Tuesday...VFR. W-NW winds 15 to 20 kt with gusts up to 30 kt. Winds diminish after 21Z. High confidence.

Outlook...

Tuesday night...VFR. Gusty west winds early in the evening, diminishing by midnight.

Wednesday through Friday...VFR. NSW.

MARINE

Gale Warning continues on the waters through tonight, may need extension into the day Tuesday. Southerly flow continues to increase, with gales likely by late day/evening just ahead of cold front. Then westerly winds likely produce gales along/just behind front for a few hours into the early morning Tuesday. Winds will relax a bit as we get into Tuesday but some lingering gale gusts may continue past dawn. Seas building thru this evening until peaking at 10-15 feet, then starting to slowly diminish late tonight through Tuesday.

Outlook...

Tuesday night...Gusty west winds diminish in the evening, but seas remain elevated. SCA may continue to be needed. No significant weather.

Wednesday through Friday...VFR. Sub-SCA conditions. No significant weather.

PHI WATCHES/WARNINGS/ADVISORIES

PA...Wind Advisory until 2 AM EDT early this morning for PAZ054-055- 060>062-070-071-101>106. NJ...Wind Advisory until 2 AM EDT early this morning for NJZ001- 007>010-012>027. Coastal Flood Advisory until 2 AM EDT early this morning for NJZ020-026. DE...Wind Advisory until 2 AM EDT early this morning for DEZ001>004. Coastal Flood Advisory until 2 AM EDT early this morning for DEZ003-004. MD...Wind Advisory until 2 AM EDT early this morning for MDZ012-015- 019-020. MARINE...Gale Warning until 6 AM EDT early this morning for ANZ430-431- 450>455.