textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Aviation section updated for 06Z TAFs.

KEY MESSAGES

1. Some areas of frost again overnight. Otherwise, generally tranquil weather is expected to prevail through the middle portion of next week.

2. Rain chances are expected to return late this week into this weekend.

DISCUSSION

KEY MESSAGE 1...Some areas of frost again overnight. Otherwise, generally tranquil weather is expected to prevail through the middle portion of next week.

High pressure will remain in place within the vicinity of our area through the middle of next week with continuing mild and dry conditions.

Overnight, low temperatures will be similar to this morning's lows, except a few degrees higher along and north of I-78. The current forecast is for low to mid 30s across interior PA and NJ areas, and upper 30s to mid 40s for the urban corridor, Delmarva, and coastal areas. So we anticipate some areas of frost developing again tonight, mainly for our PA and NJ areas outside of the urban corridor and immediate coast. Another Frost Advisory has been issued for the same areas as last night.

Scattered to broken high cloud cover will persist into next week despite surface high pressure. Temperatures are expected to increase back to above normal values early next week, with highs in the mid 60s to low 70s and milder overnights (no frost/freeze potential). Dry weather is expected to persist through the day Wednesday, when highs will reach well above normal into the low to mid 70s.

KEY MESSAGE 2...Rain chances are expected to return late this week into this weekend.

The ridging that will be in place across the area for the majority of the upcoming week will finally begin to break down by Wednesday night into Thursday as a potent upper trough over central portions of the US closes off and lifts northeastward into portions of the Great Lakes, southern portions of Ontario and Quebec, and perhaps northern New England late this week. As this occurs, broad troughing is expected to take shape across the eastern tier of the US, and a few lobes of upper level energy will likely pivot through the region Thursday and into the weekend. At the surface, low pressure centered over the Midwest is expected to track northeastward as it weakens into Thursday. After this time, there is considerable uncertainty.

At least broad low pressure looks to approach the area Thursday into Friday coincident with the period of greatest height falls across the region. This is expected to bring rain chances back to the region, potentially as early as Wednesday night, but more likely Thursday into Friday. For right now, PoPs are in the 50-60% range for most of the area during this time period. With a lack of stronger forcing and little to no instability, this looks most likely to be just a beneficial wetting rain to the region.

Heading into this weekend, ensemble guidance indicates negative H5 anomalies and generally lowered surface pressure across the region. This indicates that the pattern may remain a bit unsettled through Saturday before drier and cooler air begins to work into the region by Sunday.

AVIATION /06Z MONDAY THROUGH FRIDAY/

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

Through 12Z...VFR. Winds less than 5 kts favoring a south to southwest direction. Winds calm at times. Some patchy fog possible toward dawn. High confidence.

Monday...VFR. SW winds less than 5 kt to nearly calm in the morning, becoming SW 5 to 7 kt in the afternoon. High confidence.

Monday night...VFR to start, then areas of fog are forecast to develop after 06Z. MVFR to IFR visibility possible. South to southwest winds less than 5 kts to calm. Low confidence on fog details, but moderate confidence in fog impacting most terminals.

Outlook...

Tuesday through Wednesday...VFR is expected to prevail. Areas of fog possible Tuesday night, otherwise no significant weather.

Thursday through Friday...Rain will be possible at times with restrictions possible.

MARINE

No marine hazards through Monday. Light/variable winds 5 kts or less tonight become southwest around 10 kts Monday. Seas 1-3 feet. Fair weather.

Outlook...

Monday night through Wednesday night...No marine headlines currently anticipated with winds below 25 kt and seas below 5 feet.

Thursday through Friday...Advisory conditions possible with southeast winds increasing to 10-15 kt with gusts approaching 25 kt and seas increasing to 3-5 feet. Visibility restrictions possible at times in rain.

PHI WATCHES/WARNINGS/ADVISORIES

PA...Frost Advisory until 8 AM EST this morning for PAZ102-104-106. NJ...Frost Advisory until 8 AM EST this morning for NJZ016>018-021- 023. DE...None. MD...None. MARINE...None.