textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Updated the Aviation Section for the 00Z TAFs and portions of the Marine Section.

KEY MESSAGES

1. Tranquil weather will prevail this week continuing into the weekend with no significant weather hazards anticipated.

2. The remnants of what is now Tropical Storm Isaias will approach the area later this weekend bringing chances for rain as early as Sunday.

DISCUSSION

KEY MESSAGE 1...Tranquil weather will prevail this week continuing into the weekend with no significant weather hazards anticipated.

Aloft, a closed low will traverse portions of Ontario and the Hudson Bay and into Quebec through Friday, with long wave troughing across much of the northeastern US. Mid-level ridging will briefly build into the region for Saturday. At the surface, high pressure currently centered just offshore the Mid-Atlantic and New England coast will shift slowly eastward through tonight. A weak cold front will pass through the region during the morning and afternoon hours Thursday.

After the cooler temperatures the past couple of days, a brief warmup is anticipated, with lows tonight generally in the low to mid 50s and highs on Thursday in the mid 70s. The cold frontal passage on Thursday will usher in drier air and nudge temperatures down a bit for Thursday night and into the first part of the weekend. Near- normal temperatures are expected Thursday night through Saturday, with lows in the mid 40s to low 50s and highs in the low to mid 70s for most locations. The cold frontal passage itself is expected to be dry, so tranquil conditions are expected through Saturday.

KEY MESSAGE 2...The remnants of what is now Tropical Storm Isaias will approach the area later this weekend bringing chances for rain as early as Sunday.

The primary forecast concern for the latter part of this weekend and perhaps into early next week will be the remnants of what is currently Tropical Storm Isaias in the Gulf. It is expected to intensify into a hurricane by Thursday morning, and make landfall somewhere along the northern Gulf coast Friday night as it begins interacting with an upper trough. From there, it is expected to undergo extratropical transition and continue northward into portions of the Ohio Valley through Saturday night, and then northeastward in the direction of our area on Sunday.

Timing discrepancies remain amongst model guidance this afternoon, but there is strong agreement that the remnants of Isaias will bring some impacts to the region Sunday and perhaps into early Monday. At this point in time, it appears that widespread rain will be the primary impact. It should be noted that PWATs are modeled to be in the 1.5-2 inch range, so some periods of heavy rainfall will be possible. WPC has placed most of the region in a Marginal Risk (1 of 4) Excessive Rainfall Outlook for Sunday.

It is too early to specify exact rainfall amounts, but confidence is higher than normal that a large portion of the area could end up with 1 to 2 inches of rain, with higher amounts certainly not out of the question. We will continue to monitor trends over the coming days.

AVIATION /00Z THURSDAY THROUGH MONDAY/

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

Tonight...VFR. Few to scattered clouds move into the after midnight from west to east. South-southwest winds around 3-8 kt, becoming light and variable in a few spots. High confidence.

Thursday...VFR. A few clouds in the morning, becoming SKC in the afternoon. West-southwest winds around 5-10 kt early , become west-northwest around 10-15 kt, with gusts up to 20 kt possible in the afternoon. High confidence.

Outlook...

Thursday night through Saturday...VFR. No significant weather expected.

Sunday and Monday...Restrictions likely with the remnants of what is now Tropical Storm Isaias moving through, accompanied by low stratus and rain.

MARINE

South-southwest winds have increased this evening to around 15-20 kt. Have started to see some gusts around 25 kt off the coast of Monmouth County and near the Delaware Bay, but gusts have really been sporadic in nature and varying in occurrence. Given this, have continued to hold off on any issuance of advisories at this time. Winds will shift to westerly in wake of the a cold front on Thursday, before beginning to diminish by Thursday evening. Seas around 2 to 4 feet. Fair weather.

Outlook...

Thursday night through Saturday night...No marine headlines currently anticipated with winds under 25 kts and seas below 5 feet.

Sunday through Monday...Advisory conditions are possible with wind gusts in excess of 25 kts and seas in excess of 5 feet. Visibility restrictions are possible in rain and perhaps spray.

PHI WATCHES/WARNINGS/ADVISORIES

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