Marine Weather and Tide Forecast for Avon-by-the-Sea, NJ

NEAR TERM /THROUGH TONIGHT/
Overall forecast is on track, however, temperatures dipped a bit cooler than forecast in sheltered areas away from the urban centers. Will adjust hourly grids based on the latest surface observations, but no significant changes will be made.

Otherwise, high pressure over the Northeast and Mid-Atlantic will slide offshore today. Meanwhile, low pressure, both at the surface and aloft, over the Gulf Coast states will slowly lift to the north and east today and tonight. A warm front extending from that low will meander over the Mid-Atlantic and Delmarva Peninsula today before lifting north through Delmarva and into the Delaware Valley and southern New Jersey late tonight.

Mostly sunny to partly cloudy skies for most of today, but then clouds will increase and lower from south to north later today and tonight. Another warm and mild day with highs in the upper 70s to around 80, though cooler along the coasts, mostly in the 60s, due to onshore flow over the cooler ocean waters with sea surface temperatures in the upper 50s to around 60. A few showers associated with that warm front lay develop over Delmarva late this afternoon, but the showers will hold off until tonight.

Skies become mostly cloudy tonight as that warm front lifts north through Delmarva, the Delaware Valley, and southern New Jersey late tonight. Showers develop in the evening over Delmarva, but the bulk of the activity will hold off until after midnight. By late tonight, showers will be likely mainly west of a line from Allentown to Philadelphia to Cape May, mostly over Delmarva, the Delaware Valley, and into southwest New Jersey. Lows tonight will be warm and muggy, generally in the 50s to low 60s. With increasing low level moisture, patchy fog will develop as well.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
A closed low approaches the region on Tuesday from the southwest bringing an unsettled batch of weather for midweek. This will be in the form of widespread rain showers Tuesday and even some isolated thunderstorms Tuesday night for Delmarva and southern New Jersey.
Scattered showers continue on Wednesday across the area with some isolated thunderstorms possible. The coverage of showers starts to decrease Wednesday night as they become more isolated and a rumble of thunder still cannot be ruled out.

For Tuesday through Wednesday night, the flooding risk is low. There is a Marginal Risk (1/4) for excessive rainfall for southeast Pennsylvania and Delmarva for Tuesday and Tuesday night. This is the period when most of the rain will fall from this closed low. NBM 24 hour probability of over an inch of rain is around 40-45% for southeast Pennsylvania and closer to 60% for Delmarva. For an inch and a half of rain, the probability is 20% for southeast Pennsylvania and near 40% for Delmarva. Generally, there has been an increase in QPF values with the latest model runs. Right now, rainfall totals from Monday night through Wednesday evening look to be around half an inch to an inch for most of the area. Delmarva and parts of southern New Jersey are ranging from an inch to close to an inch and a half of rain.

As for temperatures, clouds and rain will keep the area cooler on Tuesday and Wednesday with highs in the 60s and 70s. Lows at night will be muggy and in the 50s to low 60s.

LONG TERM /THURSDAY THROUGH SUNDAY/
The closed low gradually opens back up into a shortwave trough Wednesday night as it continues moving towards the region, then finally passes overhead on Thursday. The shower coverage may be a bit more isolated Thursday morning before becoming a bit more scattered again for the afternoon. For Thursday, highs reach into the 70s for most. Temperatures do not fall too much overnight Thursday as lows are mainly in the low to mid 60s.

There is a brief lull in the unsettled weather Thursday night into Friday morning, as an upper-level ridge builds in with a weak surface high pressure system. This will allow drier conditions but does not do much in the way of cloud cover. The high pressure system does not last long as more showers and even some thunderstorms arrive for the second half of Friday. A low pressure system over the Great Lakes will lead to another active stretch of weather for the end of the week and into the weekend.

For Friday, there is a signal there for a cold front to move through later in the day which could lead to more of a focal point for showers and any thunderstorm potential. Another cold front arrives later Saturday, which could have a similar scenario as Friday by leading to a more focused area of showers and thunderstorms. Will note that these series of fronts, both Friday and Saturday, will have more instability available than the midweek system. These fronts bear watching for any severe weather potential, as the 500 mb pattern looks interesting as well. However, would not say there is an overwhelming signal for widespread severe weather at this point as this timeframe is a ways away with uncertainty but it does look active. By Sunday, there is still a slight chance for some showers to end the weekend.

AVIATION /12Z MONDAY THROUGH FRIDAY/
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas.

Today...VFR/SCT-BKN250. E winds 5 to 10 kt in the morning, becoming S after 18Z. High confidence.

Tonight...VFR through around 06Z, then CIGs /VSBYs lower to MVFR after 09Z in SHRA/BR. IFR CIGs possible at KRDG/KABE. S winds 5 kt or less. Moderate confidence.

Outlook...

Tuesday through Wednesday...Primarily IFR with showers and low clouds expected. Slight chance (15%) of a thunderstorm.

Wednesday Night through Friday...Periods of sub-VFR conditions likely (80-90%) with low clouds and scattered showers. If there were a period of VFR, it would be Thursday Night into Friday, though stratus could hang around. Thunderstorms possible Friday afternoon (30-40% chance).

MARINE
Sub-Small Craft Advisory conditions through tonight. E winds around 10 kt, becoming SE later today and tonight. Seas 2 to 3 ft. VSBY restrictions in fog and showers developing tonight.

Outlook...

Tuesday...No marine headlines expected.

Tuesday Night through Wednesday...SCA conditions expected with seas 5 to 7 feet and wind gusts near 25 kt at times, especially on the southern waters and Delaware Bay.

Wednesday Night through Thursday...SCA conditions possible (50-60%)
with seas near 5 feet.

Thursday Night through Friday...No marine headlines expected.

PHI WATCHES/WARNINGS/ADVISORIES
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.