textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Updated aviation section for 12Z TAFs.

KEY MESSAGES

1. A cool air mass likely brings frost to parts of the region tonight, particularly across the Poconos and northwestern New Jersey.

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

DISCUSSION

KEY MESSAGE 1...A cool air mass likely brings frost to parts of the region tonight, particularly across the Poconos and northwestern New Jersey.

The cool air mass will peak today as high pressure builds more firmly into the region. It will start to vacate the region tonight as the high shifts eastward and winds start to turn more southwesterly, but perhaps not quite quickly enough. While dew points will start to rise, light winds and clear skies should try to promote some radiational cooling. Undercut NBM temps most areas given this and included patchy frost in the normally cooler areas including interior southern NJ, but held the frost advisory to the far north (Poconos and Sussex NJ) where air will probably take longest to moisten back up, bringing the best chance of radiating to near freezing there. That said, wouldn't be at all shocked if some colder locations further south, particularly across the NJ Pine Barrens, made a run at 32 tonight. Also wouldn't rule out some expansion of the frost advisory, but confidence at this time is a bit too low for that.

KEY MESSAGE 2...Tranquil weather will prevail this week continuing into the weekend with no significant weather hazards anticipated.

High pressure will be in control through much of the week resulting in mostly clear/sunny skies and seasonably cool to mild temperatures.

As high pressure shifts offshore by Wednesday, airmass modification will commence. Temperatures return to more seasonable values on Wednesday, and likely go above normal on Thursday with highs in the mid to upper 70s. Temperatures look to return to near normal again for Friday and into the weekend. It should be an extended stretch of pleasant weather days with the next chance for rain not arriving until Sunday at the earliest.

AVIATION /09Z TUESDAY THROUGH SATURDAY/

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

Today...VFR. Northwest winds around 5 to 10 kt, settling out of the west late in the day. A few gusts to 20 kts around midday/early afternoon. High confidence.

Tonight...VFR. Winds becoming light/variable. High confidence.

Wednesday...VFR. Winds light/variable becoming southwest 5-10 kts. High confidence.

Outlook...

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

MARINE

Northwest winds continue into early this morning over the waters and a Small Craft Advisory remains in effect for all ocean waters through early morning. Generally expect northwest winds of 15 to 20 kt gusting up to 25 kt. As the winds begin to subside early this morning the Advisory expires in stages from south to north. Expect seas of 3 to 4 feet early lowering to 2 to 3 feet later today. Sub-SCA for the bulk of today and tonight.

Outlook...

Wednesday through Saturday...No marine hazards expected.

PHI WATCHES/WARNINGS/ADVISORIES

PA...Frost Advisory from 11 PM this evening to 9 AM EDT Wednesday for PAZ054-055. NJ...Frost Advisory from 11 PM this evening to 9 AM EDT Wednesday for NJZ001. DE...None. MD...None. MARINE...Small Craft Advisory until 10 AM EDT this morning for ANZ450>452.