textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

The Small Craft Advisory is no longer in effect.

Emphasized cooling trend starting Friday with backdoor front sliding into the region.

KEY MESSAGES

1. A weak low pressure system will cross through the region today bringing some light rain showers to the area.

2. High pressure builds into the region for Thursday with above normal temperatures, but a backdoor cold front then puts an end to them Friday.

3. Low pressure will bring widespread rainfall to the region this weekend.

DISCUSSION

KEY MESSAGE 1...A weak low pressure system will cross through the region today bringing some light rain showers to the area.

A weak low pressure system continues to approach the area from the Great Lakes region today. Through the morning, a warm front lifts northward leading to continued potential for light rain showers across the area. Following the warm front, a cold front sinks south this evening into tonight. This cold front looks rather weak, but still has the potential to lead to an isolated rain shower this evening into tonight. The best shower coverage looks to be this morning with the warm front. We trend drier overnight as a surface high pressure system approaches the region. Some patchy fog is possible overnight as some moisture gets trapped below a low-level inversion and winds turn light.

Highs today reach into the 50s for areas near and north of I-78. Areas south of I-78 get into the 60s with near 70 degree temperatures in parts of Delmarva. It will be cooler along the coast. Lows tonight are in the 40s for most.

KEY MESSAGE 2...High pressure builds into the region for Thursday with above normal temperatures, but a backdoor cold front then puts an end to them Friday.

A warm front lifts north through the region early Thursday with high pressure building over the area. A back door cold front slides through the region Friday.

Conditions will be dry with temperatures warming to above normal levels Thursday, along with highs in the low to mid 70s throughout, perhaps a touch warmer in interior south NJ and Delmarva away from the coast and bay shores..

A back door cold front will slide south through the region Friday. A few showers may develop, but conditions will otherwise be mostly dry and cooler. We currently forecast highs near 70 in the eastern shore of MD, but upper 50s in the Poconos and along the northern NJ shore and higher terrain of northern NJ, with 60s for the bulk of the region. It should be noted that guidance is notoriously bad with back door fronts and its entirely possible (as suggested by the latest NAM) that the front races southwestward much faster and we end up notably cooler than the current forecast.

KEY MESSAGE 3...Low pressure will bring widespread rainfall to the region this weekend.

Low pressure organizes and develops over the Great Lakes Friday night and pushes towards the Northeast and Mid-Atlantic on Saturday. Showers are likely throughout the day, providing what looks to be a beneficial rainfall with around 1/2 inch or so of rain. It will, however, be outright chilly with highs in the 40s to around 50. Most showers taper off Saturday night with lingering showers into Sunday. Highs will still only be in the 50s on Sunday.

Dry and warmer on Monday with highs in the 60s. Another system may arrive by Tuesday.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

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

Rest of today...Overall, VFR. Cannot rule out some brief MVFR CIGs into this evening, but confidence low in that occurring. For now, will only include at KABE. Variable winds around 5 kt.

Tonight...VFR initially, then at least MVFR conds in patchy fog and low stratus for most terminals. E winds less than 5 kt, though mostly LGT/VRB. Low confidence.

Thursday...Morning fog and stratus will lift and dissipate shortly after sunrise, then VFR. NW winds 5 to 10 kt, increase to 10 to 15 kt with gusts up to 20 kt in the afternoon. Moderate confidence.

Outlook...

Thursday night...VFR.

Friday...VFR. Cannot rule out a few light SHRA with minimal restrictions.

Friday night through Sunday...Sub-VFR at times with SHRA. Improving conds later on Sunday.

MARINE

Seas continue to subside to less than 5 feet. Therefore, the Small Craft Advisory is no longer in effect.

South to southeast winds 10 to 15 kt with gusts up to 20 kt will turn to the southwest. Winds become more northerly to north- northeast tonight at 5-10 knots. Seas around 4 feet into this evening, then 2-4 feet.

Outlook...

Thursday through Friday night...Sub-SCA conditions.

Saturday through Sunday...SCA conditions develop on Saturday and persist through the weekend. VSBY restrictions in showers Saturday through early Sunday with improving VSBYs on Sunday.

PHI WATCHES/WARNINGS/ADVISORIES

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