textproduct: Philadelphia/Mt Holly

WHAT HAS CHANGED

Added a key message for the fog that has developed this morning.

KEY MESSAGES

1. Patchy fog across the area could result in some slow downs with this morning's commute.

2. The unsettled pattern continues through Wednesday, though today will feature some improvement.

3. Drier and more seasonable conditions return for the end of the week into the weekend.

DISCUSSION

KEY MESSAGE 1...Patchy fog across the area could result in some slow downs with this morning's commute.

With recent rainfall and light winds, some patchy shallow fog has developed across the area. Areas of reduced visibility are likely to continue through the mid-morning before mixing out. Cannot rule out some areas of dense fog over more rural areas as a few 1/4SM observations have been seen. Will monitor how things trend as we go through the night and consider issuing a Special Weather Statement or even a Dense Fog Advisory. Always use low- beams when encountering fog and allow some extra time when heading out this morning!

KEY MESSAGE 2...The unsettled pattern continues through Wednesday, though today will feature some improvement.

A stationary front is positioned over our area this morning and will slowly sink southward as the day goes on. Today actually will see some marked improvement compared to the holiday weekend. A low chance (25-30%) of showers is in the forecast for southern Delmarva and far South Jersey, but most of the area should stay dry today with even some peeks of sunshine. Temperatures should hover in the upper 70s/low 80s.

The stationary front will set up over Delmarva for tonight and tomorrow, with a wave of low pressure moving along it. This will result in a few more rounds of showers for the Tuesday Night and Wednesday period, mainly for areas south of I-78. A cold front will sweep in on Wednesday from the northwest, which will put an end to the unsettled pattern. Rainfall amounts around a half inch or more are expected south of Philadelphia with anywhere from a few hundredths to a quarter of an inch expected north of the Philadelphia metro. No significant impacts are expected with these rounds of rain. Temperatures Wednesday should be similar to today, hovering around 80.

Once the cold front comes through on Wednesday Night, a transition to more tranquil and nicer weather is expected.

KEY MESSAGE 3...Drier and more seasonable conditions return for the end of the week into the weekend.

Behind the cold front from Wednesday, we trend slightly cooler for Thursday which continues into the weekend. High temperatures for most locations will be in the 70s during this timeframe and lows generally in the 50s. A high pressure system is forecast to gradually build into the region Thursday and remain in place into the weekend. A low pressure system is also forecast to move into the Northeast Friday into Saturday, but model guidance trends continue to show the high pressure system having more of an influence across our area. Due to this high pressure system in control, it looks to be a drier end of the week and continue into the weekend. to the weekend.

AVIATION /06Z TUESDAY THROUGH SATURDAY/

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

Through 12z...Tricky and uncertain forecast continues with some patchy fog developing. Have a period of MVFR/IFR VSBYs with fog/ground fog at times reducing visibility. Periods of some LIFR VSBYs at KILG/KMIV/KACY are likely at times. Winds favoring a northerly direction but primarily light/variable to calm. Low confidence.

Today...IFR/MVFR conditions should improve at most terminals by 12z-13z with fog mixing out. Some stratus near KMIV/KACY could linger for a bit, but thinking primarily VFR through the day at most sites. Winds start out east/northeast around 5 kt or less, veering and becoming southwesterly between 17z-19z around 5-10 kt. Moderate confidence.

Tonight...VFR conditions drop to MVFR/IFR with fog and stratus developing with rain moving through late in the night. Around a 10-20% chance of LIFR conditions at KACY/KMIV with stratus and/or dense fog. Winds out of the south/southwest 5 kt or less. Low confidence.

Outlook...

Wednesday...Sub-VFR possible with scattered rain showers and low clouds.

Thursday through Sunday...VFR. No significant weather.

MARINE

Sub-SCA conditions expected through Wednesday. Seas of 2 to 4 feet. A Marine Dense Fog Advisory remains in place through 6 AM for all marine zones, but may need to be extended. Will keep track observations and make a decision around the time of expiration.

Outlook...

Wednesday Night through Saturday...The conditions are anticipated to be below Small Craft Advisory criteria.

Rip Currents...

For today, winds will shift to the east-southeast, but will be 5 to 10 mph. Breaking waves will be 1 to 3 feet with a southeasterly swell around 7 seconds. As a result, there is a MODERATE risk for the development of dangerous and life threatening rip currents.

On Wednesday, winds are more out of the southwest at 5-15 mph. Breaking waves will be 1 to 2 feet with a south-southeast swell around 7 seconds. As a result, there is a LOW risk for the development of dangerous and life threatening rip currents.

Ocean temperatures are mainly in the 50s to low 60s. These cold water temperatures can quickly cause hypothermia and physical incapacitation to anyone suddenly immersed in the water.

For specific beach forecasts, visit weather.gov/beach/phi

PHI WATCHES/WARNINGS/ADVISORIES

PA...None. NJ...None. DE...None. MD...None. MARINE...Dense Fog Advisory until 6 AM EDT early this morning for ANZ430-431-450>455-480>483-485.