Marine Weather Net

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









The Marine Weather Forecast In Detail:
ANZ454 Forecast Issued: 702 AM EDT Sat Jul 20 2024

Today...Se Winds Around 5 Kt. Seas Around 2 Ft. Wave Detail: Se 2 Ft At 7 Seconds And Ne 1 Foot At 4 Seconds. Patchy Fog Early This Morning. A Slight Chance Of Showers Late. Vsby 1 To 3 Nm Early This Morning.
Tonight...Se Winds Around 5 Kt, Becoming Ne After Midnight. Seas Around 2 Ft. Wave Detail: Se 2 Ft At 7 Seconds And Ne 1 Foot At 4 Seconds. A Chance Of Showers.
Sun...N Winds Around 5 Kt, Becoming Se In The Afternoon. Seas 2 To 3 Ft. Wave Detail: Se 2 Ft At 7 Seconds.
Sun Night...S Winds Around 5 Kt. Seas 2 To 3 Ft. Wave Detail: Se 3 Ft At 9 Seconds.
Mon...Se Winds 5 To 10 Kt. Seas 2 To 3 Ft. Wave Detail: Se 2 Ft At 10 Seconds.
Mon Night...S Winds 5 To 10 Kt. Seas Around 2 Ft. Wave Detail: Se 2 Ft At 9 Seconds. A Chance Of Showers And Tstms.
Tue...S Winds 5 To 10 Kt. Seas 2 To 3 Ft. A Chance Of Showers And Tstms.
Tue Night...S Winds 5 To 10 Kt. Seas 2 To 3 Ft. Showers Likely With A Chance Of Tstms.
Wed...Sw Winds 5 To 10 Kt. Seas 2 To 4 Ft. A Chance Of Showers And Tstms.
Wed Night...Sw Winds Around 10 Kt. Seas 2 To 4 Ft. Showers Likely With A Chance Of Tstms. Winds And Seas Higher In And Near Tstms.
SHARE THIS PAGE:           
Area Forecast Discussion
National Weather Service Mount Holly NJ
916am EDT Sat July 20 2024

Weak high pressure is nearby today as a front remains stalled to our south. A weak system slides by to our north tonight, then a front settles into our area Sunday night before stalling in our vicinity through early next week. This front may dissipate Wednesday then a cold front should arrive later Thursday or Friday.

Near Term - Through Tonight
Forecast on track this morning. No changes with this update.

Overall, theNear Term - Rest Of Today Through Tonight
cast continues to feature a period of fairly typical summer weather across the region. The main synoptic features will be a weak surface trough passing to the north and a stalled frontal boundary to our south. Each of these will provide the opportunity for some showers or possibly a thunderstorm during the afternoon/evening hours today and into the overnight hours tonight. With the weak trough passing to the north, the primary focus looks to be for initiation to be the west/northwest of the region this afternoon, along the higher terrain and progressing eastward. As a result, the most likely areas to see any precipitation with the passage of this trough will be later this afternoon and northwest of the Lebanon/Lehigh/Delaware Water Gap Valleys (30-40%). CAM guidance indicates that convective activity with this trough passage may linger into the late evening/early overnight hours.

Precipitation riding along the stalled boundary to our south looks to potentially push into the region late this evening and continue through the overnight hours. The most likely areas to see any showers or storms will be in Delmarva and southeastern New Jersey. For areas across the central portion of the region, the near term forecast period looks to largely be dry, but a shower or storm drifting further south or north from the aforementioned systems cannot be completely ruled out.

Otherwise, temperatures will be within a few degrees of normal today. Temps look to top out this afternoon in the mid-upper 80s across most of the region (upper 70s to low 80s at the coast and at higher elevations). Lows tonight will be mainly in the upper 60s to low 70s.

Short Term - Sunday Through Monday Night
While temperatures are forecast to be close to average, dew points increase some through Monday and therefore it will be more humid but not oppressively hot.

As a large upper-level trough swings across eastern Canada it also pivots across the Northeast. We are forecast to be on the southern periphery of it and therefore much less forcing for ascent. A front however will approach our area from the northwest and this may provide enough forcing for an isolated afternoon/evening shower or thunderstorm especially across the northern areas. Overall though, most places should remain precipitation-free. The weak front then should settle into our area Sunday night.

The eastern Canadian upper-level trough weakens and lifts northward some Monday, however it also extends southwestward all the way into the Plains as some stronger shortwave energy drops southeastward. This places our region within southwesterly flow aloft and this will continue to increase the moisture and therefore a more humid air mass. Some embedded shortwaves within this flow aloft should arrive and this should assist in focusing enough forcing for ascent for some increase in the probability for some showers and thunderstorms Monday afternoon and night. The precipitable water values increase and therefore local downpours also increase at least some. May have to watch if some training convection is able to set up given a possible convergence area between the trough to our west and the ridge to our east. Given some uncertainty on the evolution of the convection, kept Probability of Precipitation in the 20-40 percent range.

Long Term - Tuesday Through Friday
Summary...Humid but not oppressively hot; Increased chances for convection at times.

Synoptic Overview...A strong ridge is forecast to be centered over the Southeast U.S. with a trough sliding across the Pacific Northwest with time. Meanwhile, an upper-level trough is forecast to be positioned across the Midwest/Great Lakes and back across the Mid- Mississippi Valley region. This trough is forecast to slowly get closer to the East Coast Thursday and Friday. A front stalled across our area Tuesday and Wednesday may dissipate thereafter. Low pressure tied to the aforementioned upper-level trough in the Great Lakes should track to our north, however its cold front settles into our area later Thursday and especially Friday.

For Tuesday and Wednesday...The chances for especially diurnally driven convection looks to increase as our region remains within southwesterly flow aloft well ahead of an upper-level trough. There looks to be a front also draped across our region and this should provide some additional focus for some convective development. The coverage and intensity of the convection will depend on the available instability/shear and also the timing of embedded shortwaves within the southwest flow aloft. It does appear though that with a more humid air mass in place, the most coverage of showers/storms should be each afternoon and evening. Temperatures are forecast to be closer to average, however dew points into the 70s (not as high as last weeks excessive heat stretch) will result in a rather humid feel. Given low enough temperatures however we are not anticipating excessive heat levels. Increased precipitable water values will result in stronger convection producing locally heavy rain.

For Thursday And Friday
An upper-level trough is forecast to gradually overspread the Northeast from the Great Lakes. This feature may become closed off and that could tend to slow its eastward progression at least some. The influence of this trough and the arrival of a cold front with time will provide some forcing for ascent and therefore some showers and thunderstorms once again. These may be more tied again to the afternoons and evenings. A humid air mass still in place will yield to high precipitable water and therefore locally heavy rain with any stronger convection. The approach of the upper-level trough should increase the deep-layer shear some and with the arrival of the cold front with time, will need to watch for a stronger thunderstorm risk.

No marine headlines are in effect through tonight. Mostly fair weather expected through the day today. A few showers possible (20- 30%) by later this afternoon, most likely for Atlantic coastal waters south of Cape May. Southeasterly winds around 10-15 kt. Seas around 2 feet.

Tonight, chances for showers and possibly a thunderstorm increase with the most likely areas remaining across the southern coastal waters. Winds mainly around 5 knots with seas of 2-3 feet.

Outlook... Sunday through Wednesday...The conditions are anticipated to be below Small Craft Advisory criteria.

Rip Currents... For today and Sunday, there will be a southerly wind near 10 mph with breaking waves in the surf zone of 1 to 2 feet and a 6 to 7 second period. There is a LOW risk for the development of dangerous rip currents at both the New Jersey Shore and the Delaware Beaches.

For specific beach forecasts, visit

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