Delaware Bay north of East Point NJ to Slaughter Beach DE Marine Forecast
10 - 15
5 - 10
5 - 10
5 - 10
5 - 10
|Tonight...E Winds 10 To 15 Kt With Gusts Up To 20 Kt, Becoming Ne 5 To 10 Kt Late. Waves Around 2 Ft This Evening, Then 1 Foot Or Less. Hazy With Areas Of Smoke Late This Evening And Early Morning.|
|Wed...Ne Winds 5 To 10 Kt, Becoming E In The Afternoon. Waves Around 2 Ft In The Morning, Then 1 Foot Or Less.|
|Wed Night...Se Winds 5 To 10 Kt, Becoming Ne After Midnight. Waves Around 2 Ft Or Less. A Chance Of Showers After Midnight.|
|Thu...Ne Winds 5 To 10 Kt, Becoming E In The Afternoon. Waves Around 2 Ft Or Less. A Chance Of Showers In The Morning.|
|Thu Night...Se Winds 5 To 10 Kt, Becoming Ne After Midnight. Waves Around 2 Ft Or Less.|
|Fri...N Winds Around 5 Kt, Becoming Se In The Afternoon. Waves Around 2 Ft Or Less.|
|Fri Night...Se Winds 5 To 10 Kt. Waves Around 2 Ft Or Less.|
|Sat...E Winds 5 To 10 Kt, Increasing To 10 To 15 Kt. Waves Around 2 Ft Or Less, Then Around 2 Ft.|
|Sun...E Winds 10 To 15 Kt, Becoming Se In The Evening, Then Becoming S After Midnight. Waves Around 2 Ft.|
| Area Forecast Discussion|
National Weather Service Mount Holly NJ
722pm EDT Tuesday May 30 2023
High pressure remains anchored over the Northeast through mid-week while weakening low pressure off the coast of the Carolinas will linger into Thursday. The low will continue to bring some scattered showers to the Delmarva Peninsula, but dry weather should prevail overall with increasing temperatures through the end of the week. A back-door cold front passes through on Saturday and introduces a cooler airmass for the weekend.
Near Term - Through Wednesday
Forecast on track this evening. Only minor adjustments made to the grids. Previous full discussion below... High pressure south of the Canadian Maritimes will sag to the south and east tonight through Wednesday. Meanwhile, upper low over the Mid- Atlantic continues to dissipate.
The other aspect to this forecast is smoke and haze from wildfires in Nova Scotia will spread into the region. More on that in a bit.
In terms of sensible weather, onshore flow will continue tonight through Wednesday. Another round of light rain showers may impact southern Delmarva, again with minimal Quantitative Precipitation Forecast, Wednesday afternoon.
With onshore flow and increasing low level moisture spreading into the region, patchy fog and drizzle is likely for coastal areas and areas just inland from the coast late tonight through Wednesday morning. In addition, a stratus deck will spread farther inland to about the I-95 corridor.
Clouds scatter out Wednesday morning, giving way to hazy sunshine in the afternoon.
Lows tonight will be in the mid and upper 40s to low 50s. Highs on Wednesday will top off in the upper 70s to low 80s inland, and in the upper 60s to low 70s along the coast and just inland.
Smoke from wildfires in Nova Scotia will then spread west into the region from the northeast. Latest HRRR (High-Resolution Rapid Refresh) and RAP vertically integrated smoke forecasts have one wave spreading into the region into this evening, and then another wave on Wednesday. Have included widespread haze with a smaller area of smoke. HRRR (High-Resolution Rapid Refresh) is also indicating the potential for smoke to mix down to the surface. Air Quality Alerts have been issued for all of New Jersey and southeastern PA, including the Philadelphia area. Be prepared for the smell of smoke in addition to some reduced visibility.
Short Term - Wednesday Night Through Friday
A strong upper ridge will remain overhead for the short term period while upper troughing digs across the Southwest. The flow will be quite meridional aloft and the resultant blocking pattern will hold strong through the end of the week. At the surface, high pressure remains in control while a weak surface low spins off the coast of the Carolinas.
Weak onshore flow Wednesday night will introduce a marine layer with low stratus/fog/light drizzle as moisture is trapped underneath a subsidence inversion around 900 mb. Further inland (Lehigh Valley to the Poconos) expect mostly clear skies and, with wind going light to calm, efficient radiational cooling, though warm advection will work to offset the cooling and lows will be a few degrees warmer than Wednesday night in the low 50s. In addition, expect that some haze/smoke will still be around into the early overnight, so maintained the patchy smoke mention.
Temperatures will rebound quite quickly on Friday as the NBM is still holding firm with highs in the upper 80s and low 90s, while cooler along the coast. Latest guidance has continued the slight increase of 850 mb temperatures to around 17-19C which is very close to supporting highs in the 90s. NBM prob MaxTs are indicating a >60% chance of MaxTs >90F primarily along I-95 and west, though MOS guidance is still not budging from the upper 80s. Regardless, we'll be seeing above average temperatures across the board. Forecast soundings show a very deep, dry boundary layer, so do expect that dew points will mix out in the afternoon and apparent temperatures should remain around actual air temperatures. A sea breeze should develop in the afternoon and will drop temperatures some as it progresses inland.
Long Term - Friday Night Through Tuesday
The forecast still remains more uncertain going into the weekend. The deterministic suite of guidance indicates a potent shortwave diving south out of New England and a back door surface front coming onshore on Saturday. Meanwhile, an area of surface low pressure will be sliding up the Atlantic coast, and both the GFS (Global Forecast System) and ECMWF (European Centre for Medium-Range Weather Forecasts) show the shortwave aiding in the low's development before quickly evolving into a closed low itself.
Both deterministic and ensemble guidance remains spread on the timing of the backdoor front as well as the strength and track of the surface low. The GFS and Canadian favor a very early Saturday morning passage with the ECMWF later. Ultimately, the setup is favoring a post-frontal cooldown on Saturday after a quite warm Friday with thickness values falling and cold advection with northeasterly onshore flow. Held with NBM which introduces some Probability of Precipitation (20-40%) with frontal passage on Saturday, though moisture may be overall lacking with the front. Cool high pressure is expected to build in on Sunday with mostly dry conditions and high temperatures in the low to mid 70s.
The beginning of next week looks to stay dry overall for now, but there is quite a bit of model spread regarding where this closed coastal low will end up. Current ensembles keep it a good distance offshore and mostly unimpactful to our area, though a surface boundary may sag south across the area sometime Monday. Run-to- run fluctuations continue essentially after the frontal passage Saturday, so stuck close to the consensus/NBM forecast here until we can narrow down possibilities over the next several days.
NE winds continue to diminish this evening, and will eventually settle to around 10 to 15 kt after midnight. On Wednesday, winds will be NE 10 to 15 kt with gusts up to 20 kt. Seas of 5 to 7 feet will subside to 3 to 5 feet tonight through Wednesday.
Small Craft Advisory has been allowed to expire for the lower DE Bay, and sub-SCA (Small Craft Advisory) conditions are expected for DE Bay through Wednesday. Seas remain elevated on northern NJ ocean waters through tonight, then seas will be below 5 feet through Wednesday. For southern NJ and DE ocean waters, seas remain around 5 feet through Wednesday, and SCA (Small Craft Advisory) remains in effect through Wednesday.
Outlook... Thursday...No marine headlines expected. Northeasterly wind 5-10 knots. Seas 3-4 feet.
Friday...No marine headlines expected. Southeasterly wind 5-10 knots. Seas 2-3 feet.
Saturday...Small Craft Advisory conditions possible. Northeasterly wind 5-10 knots in the morning increasing to 15-20 knots with gusts to 25-30 knots in the afternoon. Seas 2-3 feet building to 5-7 feet from north to south.
Sunday...Small Craft Advisory conditions possible. Northeasterly wind 15-20 knots with gusts to 25 knots and seas 5-7 feet in the morning. Conditions may improve later in the day.
NOAA Mount Holly NJ Office: Watches - Warnings - Advisories
PA...None. NJ...High Rip Current Risk until 9pm EDT this evening for NJZ014- 024>026. DE...High Rip Current Risk until 9pm EDT this evening for DEZ004. MD...None.
Small Craft Advisory until 6am EDT Wednesday for ANZ450-451. Small Craft Advisory until 8pm EDT Wednesday for ANZ452>455.