Delaware Bay south of East Point NJ to Slaughter Beach DE Marine Forecast
|Today...W Winds 10 To 15 Kt With Gusts Up To 20 Kt, Diminishing To 5 To 10 Kt This Afternoon. Waves Around 3 Ft This Morning, Then 2 Ft Or Less. A Slight Chance Of Showers This Morning.|
|Tonight...W Winds 5 To 10 Kt, Becoming N After Midnight. Waves 2 Ft Or Less.|
|Sat...Nw Winds 5 To 10 Kt, Becoming Around 10 Kt In The Afternoon. Waves 2 Ft Or Less.|
|Sat Night...Nw Winds 10 To 15 Kt, Diminishing To 5 To 10 Kt After Midnight. Waves 2 Ft Or Less.|
|Sun...Nw Winds 5 To 10 Kt, Becoming Sw In The Afternoon. Waves 2 Ft Or Less.|
|Sun Night...S Winds 10 To 15 Kt With Gusts Up To 20 Kt. Waves 2 Ft Or Less.|
|Mon...Se Winds 10 To 15 Kt. Waves 2 Ft Or Less.|
|Mon Night...Se Winds Around 10 Kt. Waves 2 Ft Or Less. A Chance Of Showers In The Evening, Then Showers Likely After Midnight.|
|Tue...Se Winds Around 10 Kt, Becoming Ne In The Afternoon. Waves 2 Ft Or Less, Then Around 3 Ft In The Afternoon. Showers Likely, Mainly In The Morning.|
|Tue Night...N Winds Around 10 Kt. Waves Around 3 Ft. A Chance Of Showers.|
| Area Forecast Discussion|
National Weather Service Mount Holly NJ
628am EDT Fri Oct 22 2021
Low pressure over the Great Lakes continues to track to the northeast, and this will drag a cold front across the region this morning. That front becomes nearly stationary over the Mid- Atlantic as high pressure establishes itself through the weekend. Low pressure then develops along that front and impacts the region possibly into the middle of next week.
Near Term - Through Tonight
A surface low lifting quickly northeastward into eastern Canada was allowing a cold front to approach the northern Mid-Atlantic rapidly early this morning. Expect any remaining showers to dissipate or move north of the area by daybreak, with a mostly dry forecast for today. However, a reinforcing vorticity maximum may provide sufficient lift for a few showers near or just off the Delaware and southern New Jersey coasts later this morning into early this afternoon. Additional sprinkles or light showers may occur in the Poconos, but not expecting anything measurable in this area.
Skies will be variably cloudy today given the passing midlevel perturbations, with winds becoming more west or northwest (generally 5 to 15 mph). Cold advection will not be particularly strong in the post-frontal regime given that low-level winds will not be strongly parallel to the temperature gradient. Thus, expecting today's highs to be only a few degrees lower than yesterday's (probably on the order of 5 to 10 degrees). This results in forecast highs in the upper 60s to lower 70s for most of the region (upper 50s/low 60s in the Poconos and vicinity).
The next in a series of perturbations will pivot around the upper low in Ontario/Quebec tonight, reaching the northern Mid-Atlantic by 12z Saturday. Again, cannot rule out a few sprinkles or even an isolated shower near/north of I-78 late tonight, but think the better chances will hold off until Saturday morning. With considerable cloudiness expected in advance of the vort max, overnight lows should remain seasonably mild...mainly in the upper 40s and lower 50s.
Short Term - Saturday Through Saturday Night
An upper level wave currently over Saskatchewan will move southeast around the base of an upper level trough axis and be crossing the Mid-Atlantic region Saturday afternoon. The core of the DCVA with this system looks to stay just north of the region, but is more than sufficient across NJ and eastern PA to bring a slight chance of showers to the area. As the wave moves overhead, shortwave cooling will help to steepen lapse rates with 700/500 MB lapse rates around 6 degrees C. Forecast soundings also show this, with a saturated layer between 900/700 MB. Usually when this happens, coverage tends to be slightly more widespread than initially expected. Given the above, have gone ahead and expanded the slight chance Probability of Precipitation for Saturday to cover most of NJ and eastern PA. Expect high temperatures to vary across the region, with upper 60s expected over southern DE to lower 50s towards the Poconos. The urban corridor will likely see high temperatures in the lower to mid 60s.
Late Saturday afternoon into early evening, the wave will exit the coast with weak subsidence in its wake. Skies will slowly clear with low temperatures in the lower 40s expected (upper 40s in the urban areas).
Long Term - Sunday Through Thursday
The long term will feature a rather complex upper level pattern with a potent upper level low located off the West Coast of the United States as well as another upper level low just south of the James Bay. The model depiction of how these upper level lows evolve will likely be subject to a fair amount of change over the next couple of days, until the closed low just off the West Coast of the United States can get sampled by upper air observations.
Sunday, a surface low pressure will form over Kansas and head northeast. As this occurs, surface high pressure over the Mid- Atlantic will head east with southerly winds becoming established across the region. Currently, most of Sunday looks dry with high temperatures in the mid 60s.
Sunday night into Monday, the upper level low that was just south of the James Bay will begin to shear out and head east. Simultaneously, another shortwave from the Mountain West will break off and head east. The wave will likely be crossing the Ohio Valley Monday with the area solidly in the warm sector. Most of the isentropic upglide now appears to be towards NY with more of NJ/ DE/ and PA dry. For now have just trended Probability of Precipitation down.
Monday night into Tuesday the core of the DCVA, and accompanying ~90 m height falls, will cross overhead with widespread shower development forecast. The wave will then slowly exit the region Tuesday afternoon with showers slowly coming to an end from west to east. Surface high pressure will then briefly build into the region Tuesday night through Wednesday. The second closed low, that was located off the West Coast of the United States this weekend, will then slowly approach the area on Thursday. As this occurs, the chance of precipitation will also return to the region.
Winds have diminished on lower Delaware Bay early this morning, and the small craft advisory expired at 6 am. This trend should begin on the Atlantic waters later this morning, with the small craft advisory here set to expire at noon. By tonight, north to northwest winds of 5 to 15 kt are expected, with seas of 2 to 4 feet.
Outlook... Saturday...Sub-SCA (Small Craft Advisory) conditions expected with northwest winds peaking from 15 to 20 knots. Seas from 2 to 3 feet.
Sunday...Northwest winds in the morning backing from the southwest by the afternoon hours with speeds slowly increasing to 10 to 15 knots.
Monday...Southerly winds around 15 knots with gusts approaching 25 knots. Seas 3 to 5 feet. SCA (Small Craft Advisory) conditions possible.
Tuesday...SCA (Small Craft Advisory) conditions possible as an area of surface low pressure moves east over the waters. Showers likely.
NOAA Mount Holly NJ Office: Watches - Warnings - Advisories
PA...None. NJ...None. DE...None. MD...None.
Small Craft Advisory until noon EDT today for ANZ450>455.