textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Updated Aviation section for 12z TAFS.

KEY MESSAGES

1. High pressure will bring continuing tranquil conditions through mid week.

2. A cold front will cross the area Thursday bringing the potential for a round of showers and storms.

DISCUSSION

KEY MESSAGE 1...High pressure will bring continuing tranquil conditions through mid week.

High pressure settling in over the area will bring dry and tranquil weather for the next few days. For today, expect a sunny sky with light winds and low dew points making it feel quite comfortable. Generally expect highs in the upper 70s to low 80s except low to mid 70s over the Pocono Plateau. A cool night will follow for tonight with lows in much of the area getting down into the 50s due to the light winds and mainly clear skies. Right along the coast, the Delaware Bay, and the Philly metro area it will be a bit warmer with lows generally in the low 60s. More pleasant weather will follow for Tuesday with the high pressure center right over the area. Expect continuing sunshine with low humidity and slightly warmer temperatures compared to Monday.

By Wednesday, the center of high pressure will be shifting offshore leading to a return flow from the SW setting up. This will result in a continuing warming trend with conditions also turning a bit more humid as dew points increase. However it will be partly to mostly sunny with any showers/storms staying well north of the area through the day.

KEY MESSAGE 2...A cold front will cross the area Thursday bringing the potential for a round of showers and storms.

Wednesday night into Thursday, as high pressure continues to move offshore, a southerly flow will continue to bring in warmer and more humid air. It is not entirely out of the question that as the ridge begins to break down some shower and storm chances could ultimately evolve across portions of the area Wednesday night over the Poconos into NW NJ where we currently have 15 to 30% POPs. However the better chances for showers/storms looks to arrive Thursday afternoon into the evening as a cold front moves through north to south. That said, even for this time forecast confidence is relatively low as some forecast guidance continues to indicate a drier frontal passage. POPs for this period are generally in the 40-60% range. Currently, the threat for severe storms or flash flooding concerns appears relatively low.

Following the frontal passage, high pressure building back in should bring a period of generally fair weather and seasonable temperatures for Friday through next weekend.

AVIATION /09Z MONDAY THROUGH FRIDAY/

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

Today...VFR. Light winds in the morning will settle out of the northwest around 5-10 kts in the afternoon. High confidence.

Tonight...VFR with a mainly clear sky. Winds light and variable to calm.

Outlook...

Tuesday thru Wednesday... VFR expected.

Thursday thru Thursday night...Lower CIGS/VSBYs possible with scattered showers or a few tstms.

Friday...VFR expected.

MARINE

No marine headlines are expected through today and tonight. Generally expect winds around 10 knots or less and seas around 2-3 feet.

Outlook...

Tuesday through Tuesday night...Winds/seas expected to remain below Small Craft Advisory levels.

Wednesday through Thursday....Winds/seas increasing through the day Wednesday with low end SCA conditions probable by late day Wednesday into the day Thursday. By Thursday and Thursday night there will also be chances for showers/storms to affect the waters.

Friday...Winds/seas expected to once again be below Small Craft Advisory levels.

Rip Currents...

For Labor Day, light northeast to easterly flow with winds 10 MPH or less and breaking waves 2 feet or less will result in a LOW risk for rip currents at all beaches even with a 8 to 10 second period.

For Tuesday, winds turn more offshore and remain relatively light. Breaking waves again will be around 1 to 2 feet with another 8 to 9 second period swell. This will also result in a LOW risk for rip currents at all shore points.

PHI WATCHES/WARNINGS/ADVISORIES

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