Marine Weather Net

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


TODAY

W
WINDS
5 - 10
KNOTS

TONIGHT

SW
WINDS
5 - 10
KNOTS

SAT

NE
WINDS
10 - 15
KNOTS

SAT NIGHT

NE
WINDS
5 - 10
KNOTS

The Marine Weather Forecast In Detail:
ANZ454 Forecast Issued: 401 AM EDT Fri Jul 03 2020

Today...W Winds 5 To 10 Kt, Becoming Sw Late. Seas Around 3 Ft This Morning, Then 2 Ft Or Less. Swell Mainly From The Se With A Dominant Period Of 8 Seconds.
Tonight...Sw Winds 5 To 10 Kt, Becoming Ne After Midnight. Seas 2 Ft Or Less. Swell Mainly From The Se With A Dominant Period Of 8 Seconds.
Sat...Ne Winds 10 To 15 Kt. Seas Around 3 Ft. Swell Mainly From The Se With A Dominant Period Of 9 Seconds.
Sat Night...Ne Winds 5 To 10 Kt. Seas Around 3 Ft. Swell Mainly From The Se With A Dominant Period Of 9 Seconds.
Sun...Ne Winds Around 5 Kt, Becoming Se In The Afternoon. Seas Around 3 Ft.
Sun Night...S Winds 5 To 10 Kt. Seas Around 3 Ft In The Evening, Then 2 Ft Or Less.
Mon...S Winds 5 To 10 Kt. Seas 2 Ft Or Less.
Mon Night...S Winds 5 To 10 Kt. Seas Around 3 Ft.
Tue...S Winds Around 5 Kt, Increasing To 10 To 15 Kt In The Afternoon. Seas 2 Ft Or Less, Then Around 3 Ft In The Afternoon.
Tue Night...S Winds 10 To 15 Kt. Seas Around 3 Ft.
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Area Forecast Discussion
National Weather Service Mount Holly NJ
450am EDT Fri July 3 2020

Synopsis
High pressure builds over the area today, but a weak cold front will drop south through the region later today through tonight. High pressure returns for the weekend, and will be in place into the new week. Several disturbances will pass through the region as well through the middle of next week.

Near Term - Until 6am This Morning
The main story today will be the late afternoon and evening thunderstorm potential as well as the hottest day so far this year across portions of the forecast area.

The upper low will continue pushing south and east of the area today as ridging builds to our west resulting in northwest flow aloft. At the surface, high pressure will remain well west of the area with weak low pressure located just offshore. Additionally, surface ridging will begin to push into the area from the northeast toward the latter half of the day as an associated backdoor front sinks into the region into the evening.

While northwesterly flow around 5-10 mph will prevail at the surface through much of the day, dewpoints will remain mostly in the low to mid 60s area wide resulting in ML/SBCAPE values in the 1000 J/kg neighborhood. A mid-level impulse is forecast to approach the area from the Hudson River Valley toward the late afternoon bringing forcing aloft and deep layer shear on the order of 25 kts. This combined with the backdoor front is forecast to result in the development of scattered thunderstorms mainly north of the I-76 and I-195 corridors, however some more isolated activity cannot be ruled out farther south across the Philly metro, southern NJ, and Delmarva, especially into the evening. Storms could be strong to locally severe with gusty to locally damaging winds possible in the strongest storms. The highest, albeit marginal, severe thunderstorm threat will be generally along and north of the I-78 corridor from about the 5 PM to 8pm hours. Additionally, PWAT (Precipitable Water) values will be on the order of 2.00", so heavy rain may become a concern where convection tends to train, especially across more urbanized areas in the vicinity of the backdoor front. WPC has added a slight risk for excessive rainfall centered across northern New Jersey to highlight this threat.

Moving on to temperatures, a rather hot day is shaping up for much of the region, the hottest day so far this year for some. 850 mb temps are forecast to be in the 19-20 C range. This combined with the northwest flow will add some downsloping effects to further enhance the warming today. The result will likely be widespread temperatures in the mid 90s away from the coasts and highest terrain, where temperatures in the mid to upper 80s can be expected. With dewpoints mixing down into the low 60s where the highest temperatures are forecast, it will not feel oppressively hot and heat indicies will top out in the mid to upper 90s. The biggest question mark with regard to the temperature forecast will be how much cloud cover develops, especially toward the peak afternoon heating hours, however given the aforementioned factors, I don't believe the cloud cover will matter too much, especially from the Philly metro and points west and south.

Short Term - 6am This Morning Through 6am Saturday
Scattered showers and storms are forecast to decrease in coverage and strength as the evening progresses and instability wanes. The surface ridging will be taking control of the sensible weather during this time as well and temperatures will fall into the 70s and upper 60s into the overnight period along with east to northeasterly winds around 5-10 mph and increasing cloud cover.

Long Term - Saturday Through Thursday
Cold front will be south of the region and across the Mid- Atlantic by Saturday morning. A more seasonal airmass spreads into the region with closer to normal temperatures. Some shortwave energy passing through the region Saturday afternoon may trigger some isolated to scattered showers and thunderstorms.

Thereafter, high pressure builds in from the west, and an increasingly hot and humid airmass will spread east into much of the upcoming week. Temperatures will warm into the upper 80s and low 90s Sunday, and then into the low to mid 90s as the new week progresses. In addition, surface dewpoints will generally be in the low to mid 60s, rising to around 70 by Thursday. This results in max heat index values generally in the upper 90s Monday through Thursday. If conditions are just a bit warmer or a bit more humid, Heat Advisories may be needed.

Conditions should be dry on Sunday, but then afternoon and early evening convection will be possible each day starting on Monday as some shortwaves pass through the region. Given how humid it will be, locally heavy rain could be a threat.

Marine
Today and tonight...Conditions are forecast to remain below advisory criteria through the period. Seas will be 1-2 feet across Delaware Bay and 2-3 feet across the ocean waters. Initially offshore winds around 10 kts will shift easterly during the afternoon and increase to around 10-15 kts. Scattered showers and thunderstorms during the late afternoon and evening.

Outlook... A prolonged period where winds and seas will generally be below SCA (Small Craft Advisory) criteria from Saturday through Tuesday. Scattered afternoon and evening showers and thunderstorms possible on Saturday, and then again on Monday and Tuesday. Seas on the ocean will be mostly 2 to 3 ft.

Rip currents...Surf zone waves less than 2 feet will result in a low risk for rip currents today. Some areas may approach a moderate risk Saturday with onshore winds.

Tides / Coastal Flooding
Astronomical high tide levels will continue to rise as there will be a full moon this weekend. The evening high tides are over a foot higher than those in the morning.

A developing east to northeast wind may result in widespread minor flooding around the evening high tide both tonight and Saturday. The minor flooding could work its way up Delaware Bay and into the tidal Delaware River, as well. Issues are not anticipated with the morning high tides.

Based on the latest guidance this morning, will hold off on issuing a Coastal Flood Advisory with the high tide tonight. Many sites are just touching Advisory criteria, with just Cape May and Bowers Beach getting well into Advisory criteria. Will see how easterly flow develops today, as a Coastal Flood Advisory may be needed tonight.

Tidal flooding is not expected on the upper eastern shore of Chesapeake Bay.

Equipment
The NOAA Weather Radio All Hazards broadcast from Hibernia Park, PA (WNG704) remains off the air until further notice due to damage to the antenna during the June 3 Derecho.

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