Marine Weather Net

Cape May NJ to Cape Henlopen DE out 20 nm Marine Forecast


OVERNIGHT

S
WINDS
10 - 15
KNOTS

THU

SE
WINDS
5 - 10
KNOTS

THU NIGHT

NW
WINDS
10 - 15
KNOTS

FRI

W
WINDS
15 - 20
KNOTS

The Marine Weather Forecast In Detail:
ANZ454 Forecast Issued: 1003 PM EDT Wed Apr 14 2021

Overnight...S Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas Around 3 Ft. Rain. Vsby 1 To 3 Nm. Swell Mainly From The E With A Dominant Period Of 9 Seconds.
Thu...Se Winds 5 To 10 Kt, Becoming N Late In The Morning, Then Becoming Nw In The Afternoon. Seas 3 To 4 Ft. Rain Likely, Mainly In The Morning. Vsby 1 To 3 Nm. Swell Mainly From The E With A Dominant Period Of 11 Seconds.
Thu Night...Nw Winds 10 To 15 Kt, Increasing To 15 To 20 Kt In The Late Evening And Overnight. Gusts Up To 30 Kt. Seas 3 To 5 Ft. A Chance Of Rain Early In The Evening. Swell Mainly From The E With A Dominant Period Of 10 Seconds.
Fri...W Winds 15 To 20 Kt With Gusts Up To 25 Kt. Seas 4 To 5 Ft. Swell Mainly From The E With A Dominant Period Of 11 Seconds.
Fri Night...Nw Winds 15 To 20 Kt With Gusts Up To 25 Kt. Seas 3 To 5 Ft.
Sat...Nw Winds 10 To 15 Kt. Gusts Up To 20 Kt In The Morning. Seas 3 To 4 Ft.
Sat Night...W Winds 5 To 10 Kt. Seas Around 3 Ft In The Evening, Then 2 Ft Or Less.
Sun...Nw Winds Around 5 Kt, Becoming S In The Afternoon. Seas 2 Ft Or Less.
Sun Night...S Winds Around 10 Kt, Becoming W After Midnight. Seas 2 Ft Or Less.
Mon...W Winds 5 To 10 Kt. Seas 2 Ft Or Less.
Mon Night...W Winds Around 10 Kt. Seas 2 Ft Or Less.
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Area Forecast Discussion
National Weather Service Mount Holly NJ
959pm EDT Wednesday April 14 2021

Synopsis
Strengthening and slow moving coastal low pressure is expected to progress from off the coast of Virginia to over New England from tonight through Friday before it eventually departs to the northeast. Weak high pressure returns briefly on Saturday, then a few disturbances will keep a slight chance of rain in the forecast for Sunday and Monday. A cold front is expected to cross the region Tuesday or Wednesday of next week, with a generally unsettled pattern expected to continue well into next week.

Near Term - Through Thursday
No significant changes expected to the forecast so far this evening. Our area is in between two systems, one an area of low pressure that is forecast to move offshore of the Virginia coast later tonight and move to the northeast Thursday, while another low pressure remains nearly stationary across southern Quebec through Thursday, slowly pulling a cold front to the east.

Light rain will continue to spread across Maryland, Delaware, and southern New Jersey this evening and overnight north of the surface low to our south as several short wave/vorticity impulses move across the area as well. As the cold front approaches the area early on Thursday and the low pressure strengthens offshore of the east coast, rainfall will likely spread across much of the area. With each set of model runs, the axis of the heaviest rain continues to trend northeastward. It now appears as though it will set up in eastern New York and southwestern New England, sparing our area any concern for flooding.

There will be somewhat of a rainfall gradient in our region. Most locations will likely receive a quarter to a half inch. However, an area of less than a quarter inch amounts should extend into southeastern Pennsylvania and northern Delaware from the west. Some locations in northern and central New Jersey are still expected to receive at least a half to three quarters of an inch.

Tonight's low temperatures will favor the upper 40s and lower 50s with a light and variable wind. Thursday's highs are forecast to be mainly in the 50s and lower 60s. The wind will likely be variable in the morning. A cold front arriving from the west in the afternoon should cause the wind to become westerly at 5 to 10 MPH.

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... An upper closed low will pass from the southeastern Great Lakes region late Thursday to southern New England by mid-day Friday. This feature will bring 2 notable mid-level vorticity maxima into the forecast area, the first arriving late Thursday and the second during the day Friday. At the surface, a strengthening surface low will be located offshore to our east or northeast through this period.

The axis of heaviest Quantitative Precipitation Forecast has shifted northeast of our forecast area, and the bulk of the precipitation associated with the first vorticity maxima should be departing the area to the northeast late Thursday evening and overnight. As the upper low slides across the northern portion of the forecast area Thursday night, there could be a change over to snow across the southern Poconos and higher elevations. But with the axis of Quantitative Precipitation Forecast (forcing for ascent to produce precip) moving out of the region as the colder air arrives, the chances for snow have come down quite a bit from what was previous expected. Perhaps a brief coating of snow may occur if a burst of snow comes to fruition, but chances for this are low.

Thursday's cloudiness is also expected to lift north overnight as well with most locations outside of northwestern New Jersey and the Poconos experiencing mostly clear conditions by daybreak Friday. The strengthening low offshore and falling heigheights with the upper low moving in overnight should result in a persistent northwesterly breeze overnight with speeds around 10-15 mph and gusts up to 20 mph. Expect low temperatures in the lower 40s near and south of the Philly metro with mid to upper 30s farther north.

The second vorticity maxima arrives during the day Friday. Cloudiness will return from at least are the Philly metro and north. This period should stay largely dry owing to downsloping and drier air moving into the column as the better forcing arrives, but some areas of light rain can't be completely ruled out from around Philly north, so we've maintained a slight chance to chance Probability of Precipitation for this period. The vorticity maxima and further strengthening of the pressure gradient will result in a rather breezy day across the area, especially for southeastern Pennsylvania, southern New Jersey, and Delmarva. Expect northwesterly winds 15-20 mph with gusts up to 30 mph. The downsloping should also help boost temperatures a bit higher than guidance into the mid to upper 50s, but it will certainly not feel like a "nice" day given the breezy conditions and increasing clouds throughout the day.

The gusty northwesterly winds are forecast to gradually abate into the overnight hours Friday night and skies will begin to clear. Expect lows once again in the low 40s south to mid to upper 30s north. Saturday should be a more pleasant day with temperatures warming to near 60 degrees, but the northwesterly breeze will continue around 10-15 mph with gusts up to 20 mph. Clouds will be gradually increasing into the afternoon as the next shortwave trough begins moving closer to the region from the west, but the daytime hours are forecast to remain dry.

Long Term - Saturday Night Through Wednesday
The next shortwave trough will pass from the Ohio Valley on Saturday across the forecast area Saturday night amid a broader zonal flow. This will be associated with the closed upper low currently centered across the western CONUS. Another shortwave trough should pass south of the area Sunday night into Monday. Both features will result in increasing cloudiness and some chances for rain. Moisture will remain limited, so confidence is not high on the exact timing and coverage of the possible rain at this time. Temperatures should remain near normal during the period along with light winds.

Guidance seems to be pretty consistent in bringing a cold front toward the region late Tuesday into early Wednesday associated with a northern stream mid-level wave passing to our north. As a result, Tuesday should be a warm day with above normal temperatures and southwesterly winds. Moisture appears to remain limited, so the cold front appears to be a dry one at this time.

Marine
A southwest wind 10 to 15 knots is forecast to become southeast 5 to 10 knots late tonight. The wind should then back to the northeast, then to the north and northwest during the course of the day. Speeds are expected to increase back to 10 to 15 knots late in the day.

Wave heigheights on our ocean waters are expected to be mainly 3 to 4 feet. Waves on Delaware Bay should be 2 feet or less.

Outlook... Thursday night through Friday night...West to northwesterly winds and seas will build Thursday night and elevated conditions will persist through at least early Friday night. Expect winds of 15-20 kts with gusts of 25-30 kts during the period along with seas of 4-6 feet. A Small Craft Advisory will likely be needed for this time period.

Saturday through Monday...Sub-advisory conditions area expected with winds of 5-10 kts with gusts up to 15 kts at times. Seas 1-3 feet.

NOAA Mount Holly NJ Office: Watches - Warnings - Advisories
PA...None. NJ...None. DE...None. MD...None. MARINE...None.