textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Updated aviation section for 12z TAFs.

KEY MESSAGES

1. One more round of some showers and thunderstorms looks to affect the area late day Friday into Friday evening. Isolated to scattered severe thunderstorms will be possible with this round mainly for our southernmost counties in Delmarva.

2. The Labor Day Weekend will feature mostly dry weather with at or below normal temperatures and lower humidity.

DISCUSSION

KEY MESSAGE 1...One more round of some showers and thunderstorms looks to affect the area late day today into this evening. Isolated to scattered severe thunderstorms will be possible with this round mainly for our southernmost counties in Delmarva.

Heading into the day today, a diffuse frontal boundary will remain near the area but it will be a bit farther south compared to Thursday. As a result, we do expect one more round of some showers and thunderstorms to affect the area late afternoon into the evening but the severe weather threat will be more limited in areal extent. In fact at this point only our southernmost counties in Delmarva are highlighted by the Storm Prediction Center as areas that could see isolated to scattered severe thunderstorms. Damaging winds look to be the biggest threat with any storms that turn severe. Also, heavy rainfall will be possible with any storms and this could lead to localized flash flooding if any training of storms were to develop. Otherwise it will be another warm and humid day although not as much so as Thursday. Heat indices look to top out in the 80s north and the 90s south which is below Heat Advisory criteria.

Storms may linger into this evening before moving out overnight.

KEY MESSAGE 2...The Labor Day Weekend will feature mostly dry weather with at or below normal temperatures and lower humidity.

By Saturday, the trend among model guidance shows the frontal boundary south of our region, with Canadian high pressure building in across the Northeast and Mid-Atlantic. This will largely end any shower and thunderstorm potential. Thus, Labor Day Weekend is still shaping up to feature nice weather, with temperatures trending at or slightly below normal and lower humidity.

AVIATION /09Z FRIDAY THROUGH TUESDAY/

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

Today...Mainly VFR this morning. Another round of SHRA/TSRA may impact the terminals late in the afternoon and in the evening. Confidence is still rather low on the details of this next round but we've indicated prob30 groups for thunder for most TAF sites. The exception is ABE as storms look to stay south of there. W-NW winds around 10 kt with a few gusts to 20 kt possible in the morning. Low confidence on TSRA potential.

Tonight...Restriction possible in the evening due to storms and then some patchy rural fog possible overnight. Low confidence.

Outlook...

Saturday through Tuesday...Primarily VFR conditions expected.

MARINE

Winds and seas are generally expected to stay below Small Craft Advisory conditions. However, another round of storms may affect the waters Friday evening bringing localized gusty winds.

Outlook...

Saturday through Tuesday...generally Sub-SCA conditions are expected through the period however northeast winds on Sunday could get close to SCA levels.

Rip Currents...

For Friday, winds turn offshore, with west/northwest winds 10 MPH or less. Breaking waves also around 2 feet or less expected with a dominant period of 8 seconds. With relatively tranquil conditions in the surf zone, a LOW risk for rip currents is expected at all beaches.

For Saturday, winds turn more northerly, though still light. Similar surf zone conditions expected at all beaches will result in another LOW risk for all shore points to start the holiday weekend.

PHI WATCHES/WARNINGS/ADVISORIES

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