textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

A Small Craft Advisory is now in effect for Delaware Bay for tonight.

KEY MESSAGES

1. Low pressure passes north of the area tonight and drags a cold front through the region on Friday.

2. Mild and unsettled pattern takes hold as early as Monday Night next week.

DISCUSSION

KEY MESSAGE 1...Low pressure passes north of the area tonight and drags a cold front through the region on Friday.

High pressure is southeast of the Canadian Maritimes and continues to drift out to sea. Southwest winds increase later today as the pressure gradient tightens between the offshore high and a cold front approaching from the west. Warm air advection will be underway today, and highs will top off in the low to mid 70s. These highs are some 15 to 20 degrees above normal. Skies will be partly to mostly sunny, but clouds will increase late in the day as that front draws nearer.

Low pressure passes north of the area tonight, and this will pull a cold front south through the region. Showers develop this evening, and continue through tonight. The front will be through most of the region by Friday morning, then will become nearly stationary over the Delmarva Peninsula most of the day before finally sagging towards the Mid-Atlantic late in the day. Showers taper off over the southern Poconos, northern New Jersey, and the Lehigh Valley in the morning, and then showers continue over southern New Jersey, the Delaware Valley, and Delmarva most of the day. Some elevated this evening may result in a rumble of thunder or two this evening, but severe weather is not expected.

Temperatures drop during the day Friday as cold air advection will be underway. Temperatures will be in the mid to upper 50s for most of the area and in the low to mid 60s in the morning, and will fall into upper 40s to low 50s through the afternoon.

KEY MESSAGE 2...Mild and unsettled pattern takes hold as early as Monday Night next week.

High pressure that dominates this weekend resulting in dry and quiet weather will move offshore on Sunday. Return flow sets up, ushering in a warmer airmass after below normal temperatures on Saturday, and near normal temperatures on Sunday. Warm south/southwesterly flow for the beginning and middle part of next week will result in a stretch of above normal temperatures for the early and middle portion of next week.

While it will be on the more mild and warmer side next week, there will be multiple chances for rain as several frontal systems slide by. None of these systems look overly impactful at this point, but there could be some periods of rain, beginning late Monday and continuing off and on through the middle of the week.

AVIATION /06Z THURSDAY THROUGH MONDAY/

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

Early this morning...VFR. Light S winds. LLWS at 2000 ft with SW winds 40 to 45 kt. LLWS ends prior to 12Z. High confidence.

Today...VFR. SW winds 5 to 10 kt in the morning, increasing to 10 to 15 kt with 20 to 25 kt gusts after 16Z. Winds at 200 ft increase to 45 to 50 kt prior to 00Z at KRDG/KABE. Some -SHRA may move into KRDG/KABE prior to 00Z as well. Moderate confidence.

Tonight...Sub-VFR CIGs/VSBYs in -SHRA. LLWS at 2000 ft for SW winds 45 to 50 kt from around 00Z to 06Z. SW winds around 10 kt with gusts up to 20 kt, turning W-NW at around 10 kt after 06Z, then N by 12Z. Moderate confidence.

Friday...Sub-VFR in -SHRA and low CIGs. N winds 8 to 12 kt. Moderate confidence.

Outlook...

Friday Night...Lingering MVFR/IFR restrictions possible for the first half of the night, but conditions should lift to VFR by daybreak Saturday.

Saturday...VFR. Northwest wind gusts between 20-25 kt.

Saturday Night through Monday...VFR. No significant weather.

MARINE

South to southwest winds increase to 15 to 20 kt with 25 to 30 kt gusts later this morning on the ocean waters and will continue through tonight. Winds increase on Delaware Bay tonight. A cold front passes through the waters tonight, and winds turn north around 10 kt with gusts up to 20 kt on Friday.

A Small Craft Advisory remains in effect for the ocean waters today through tonight, and a Small Craft Advisory is now in effect for Delaware Bay for tonight.

Outlook...

Friday Night through Saturday...SCA conditions expected as wind gusts 25-30 kt pick up after a cold front moves through late Friday Night. Gusts continue through Saturday afternoon. Seas could near 5 feet at times.

Saturday Night through Sunday Night...No marine headlines expected.

Monday...SCA conditions likely (60-70%) as winds pick up out of the south/southwest around 20-25 kt and seas 4 to 6 feet.

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 8 PM this evening to 8 AM EDT Friday for ANZ430-431. Small Craft Advisory from 8 AM this morning to 8 AM EDT Friday for ANZ450>455.