Marine Weather and Tide Forecast for Dover Beaches South, NJ

KEY MESSAGES
1. Patchy areas of freezing fog and black ice possible again tonight, mainly southeast of I-95.

2. An arctic front Sunday will bring some wintry weather to our northern areas, possibly extending into the Philly metro.

3. Several waves of low pressure will impact the area over the middle to latter part of next week with some wintry precipitation possible Tuesday.

4. A significant warm-up is expected late next week.

DISCUSSION
KEY MESSAGE 1...Patchy areas of freezing fog and black ice possible again tonight, mainly southeast of I-95.

Mild air will persist across the region rest of today with plenty of snow melt continuing across those areas which still have some. This, combined with light winds under waning high pressure, should promote more fog development tonight, particularly across the coastal plain where snow persists, melting is maximized by warmer temps, and winds should be light before an approaching cold front stirs up the atmosphere later tonight. Fog or freezing fog advisories may be needed for portions of New Jersey and/or the Delmarva overnight. Further northwest, the approaching front plus colder daytime temps and/or little snow left to melt mean fog is considerably less likely northwest of I-95.

KEY MESSAGE 2...An arctic front Sunday will bring some wintry weather to our northern areas, possibly extending into the Philly metro.

Cold front stalls over the area late tonight with a wave of low pressure riding eastward along it. This will allow some snow showers to overspread our northern regions as the day wears on, with some sleet and rain showers likely further south. Because of the frontal boundary stalled in the area, and early morning inversion, its possible some spotty freezing rain could occur in areas north of Philadelphia during the morning, but right now odds of this look too low for any headlines. As colder air bleeds southward behind the system, any lingering showers may change to sleet and snow before ending as far south as Philly proper, then precip should be all done by later in the afternoon. Accumulations should be confined to areas north of Philly though, with most areas seeing less than an inch. Around an inch is the most likely accumulation across the southern Poconos and NW NJ, however. Temps near freezing early will likely rise a bit in the morning before falling again in the afternoon behind the system, with highs mostly in the 30s north of Philly and mostly 40s south.

KEY MESSAGE 3...Several waves of low pressure will impact the area over the middle to latter part of next week with some wintry precipitation possible Tuesday.

The region will be under the influence of high pressure centered over the northern Great Lakes during the early part of the week. The high will gradually shift eastward north of the area before sliding offshore by Tuesday morning.

A mid-level impulse will traverse the region on Tuesday. While somewhat subtle, it will still provide for synoptic scale ascent. At the surface, an initially stationary boundary looks to lift north towards the region as a warm front, with widespread light precipitation expected to overspread the region from west to east on the northern side of the boundary Tuesday.
Overnight lows Monday night look to be in the 10s and 20s areawide, so snow would be the favored precipitation type for a period Tuesday morning. The primary question is how quickly precipitation moves in, as temperatures are expected to warm up fairly quickly during the daytime hours into the upper 30s to mid 40s. At the moment, the expectation is for a period of snow or a rain snow mix for the I-95 corridor and points northwest Tuesday morning, transitioning to all rain. Any snow accumulations look to be under an inch, with the exception being across the southern Poconos where cold air could hang on a little bit longer and allow for amounts closer to an inch. By Tuesday afternoon, precipitation is expected to change to all rain across the entire area. Total QPF from this event looks to be in the neighborhood of 0.5 to 0.75 inch along and north of I-78, with slightly lower amounts south.

Tuesday night, the front is expected to begin shifting southward again, temporarily brining rain chances to an end by Wednesday morning. With that said, the pattern in place looks to remain fairly progressive through the end of the week, with the NBM featuring PoPs ranging from 20-50% each day Wednesday through Saturday. Given the progressive pattern and inherent uncertainties at this range, have opted to continue with PoPs generally in the slight chance to chance range each day.

KEY MESSAGE 4...A significant warm-up is expected late next week.

A substantial warming trend is expected to begin across the area Wednesday through Saturday. Some locations could see highs exceed seasonal norms by as much as 15-20 degrees, particularly on Thursday and beyond.

After the departure of the Tuesday system, additional mid-level impulses are expected to continue to pass through the region at times bringing continued unsettled weather. However, strong ridging over the Southeast and portions of the western Atlantic will expand northward. This will set the stage for multiple periods of return flow, with only brief pauses as weak disturbances pass through.

The 13Z NBM depicts the expected warming trend well. On Wednesday, probabilities of highs exceeding 60 degrees range from 20-50% across Delmarva, and are generally under 20% elsewhere. By Thursday, the entire region has at least a 20% chance of exceeding 60 degrees, with probabilities ranging from 50-80% across far southern NJ and Delmarva. Probabilities continue to increase through Saturday, with over 50% chance of exceeding 60 degrees across the entire area, and over 90% across Delmarva.

Forecast highs Wednesday look to be in the upper 40s to mid 50s for most, with temperatures warming into the 50s and 60s for Thursday and Friday. By Saturday, many locations from Philly south may approach or exceed 70. Overnight lows generally look to be in the 40s each night, with portions of Delmarva and the urban corridor potentially seeing a couple of nights with lows above 50.

AVIATION /18Z SATURDAY THROUGH THURSDAY/
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas.

Rest of Today...VFR. Winds south-southwest around 4-8 kt.
Moderate confidence overall.

Tonight...Prevailing VFR expected early. Another round of low clouds and dense fog possible for I-95 terminals, MIV and ACY.
RDG and ABE have the best chance to remain VFR throughout the night. Winds light and variable early, becoming east-northeast around 3-5 kt late. Low confidence.

Sunday.. MVFR to IFR expected at times, first due to low clouds/fog mainly terminals from PHL southeast, then due to rain/snow mix mainly for terminals northwest of PHL. Northwest winds may occasionally gust up to 20 kt in the afternoon. Low confidence.

Outlook...

Sunday night through Monday...VFR. No significant weather.

Monday night...Primarily VFR. Sub-VFR conditions could develop late in light snow.

Tuesday through Tuesday night...Sub-VFR conditions expected in rain and snow Tuesday morning, and rain Tuesday afternoon into Tuesday night. Conditions look to begin to improve late Tuesday night.

Wednesday through Thursday...Primarily VFR. Brief periods of sub-VFR conditions are possible with a chance of rain.

MARINE
No marine headlines are in effect through Sunday. Southwest winds around 5 kt this afternoon into this evening. Overnight, winds will become northeast around 5-10 kt following a frontal passage. Seas around 2 feet. Patchy areas of locally dense marine fog are possible later tonight. Winds become northwest and gust up to 20 kt with seas around 2-3 feet by afternoon.
Dense fog possible early, then showers possible later in the day.

Outlook...

Sunday night...SCA conditions are possible with north winds 10-15 kt and gusts around 20 kt. Seas 3-5 feet.

Monday through Tuesday...Sub-SCA conditions expected with winds below 25 kt and seas below 5 feet.

Tuesday night through Wednesday...SCA conditions possible.
South- southwesterly winds 10-15 kt and gusts 20-25 kt with seas 3-5 feet. Conditions are likely to improve through the day on Wednesday.

Wednesday night...Sub-SCA conditions expected with winds below 25 kt and seas below 5 feet.

Thursday...SCA conditions possible with southwesterly winds increasing to 10-15 kt and gusts 20-25 kt. Seas 3-5 feet.

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