Chester, PA Weather

What Has Changed

Aviation section updated for 00Z TAFs.

Marine section updated.

Key Messages

1. Elevated tide cycles persist due to Post- Tropical Cyclone Josephine well off the coast, resulting in widespread minor coastal flooding continuing for back bay areas in Ocean County, NJ and Sussex County, DE.

2. Frost and freeze impacts tonight and Saturday night where the growing season continues.

Discussion

KEY MESSAGE 1...Elevated tide cycles persist due to Post- Tropical Cyclone Josephine well off the coast, resulting in widespread minor coastal flooding continuing for back bay areas in Ocean County, NJ and Sussex County, DE.

Post-Tropical Cyclone Josephine has pulled away from the region as it's now over the Canadian Maritimes. However elevated water levels persist, mainly in the back bay areas of Ocean County, NJ and Sussex County, Delaware. The Coastal Flood Advisory for these counties is in effect until 7 AM Saturday.

KEY MESSAGE 2...Frost and freeze impacts tonight and Saturday night where the growing season continues.

A Freeze Warning was issued for areas north and west of the I-95 corridor from midnight until 9 AM Saturday where the growing season remains active. For the I-95 corridor and areas south and east, a Frost Advisory was issued from midnight until 9 AM Saturday for all other zones, excluding Sussex County in Delaware and the barrier islands in New Jersey.

As an upper-level trough pivots across the Northeast tonight, a strong mid-level ridge in the Plains to Midwest shifts eastward through the weekend. This will support strong surface high pressure shifting eastward into the Northeast and Mid-Atlantic through the weekend.

A chilly and dry airmass will accompany this strong surface high, and as the high itself settles more overhead, forecast soundings show surface winds decoupling. This will set the stage for efficient radiational cooling both tonight and Saturday night. The forecast lows are in the upper 20s to mid 30s for much of the area (with the only exception along the immediate coastal strip) with a favorable setup for frost and freeze. Some scattered to broken cirrus will be in place overnight. However, the thin cloud coverage will be the only limiting reagent to the efficient radiational cooling. This will probably slow cooling down by a few degrees at best, likely aiding to prevent a widespread freeze situation, but it is not expected to slam the brakes hard on the efficient radiational cooling setup overnight.

Aviation

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

Tonight...VFR. Winds will go calm for a time, then increase slightly out of the north to northeast less than 5 kts after 06Z. High confidence.

Saturday...VFR. Winds 5 kts or less favoring a north to northeast direction early, then shifting more easterly and becoming variable after 18Z. Winds may become calm at times. High confidence.

Saturday night...VFR/SKC. Calm winds. High confidence.

Outlook...

Sunday through Wednesday...VFR. No significant weather expected.