Cape Henlopen to Fenwick Island DE out 20 nm Marine Forecast
| This Afternoon...S Winds 25 To 30 Kt With Gusts Up To 40 Kt. Seas 9 To 12 Ft. Wave Detail: Se 11 Ft At 9 Seconds. Showers With A Chance Of Tstms. |
| Tonight...S Winds 30 To 40 Kt, Becoming W 25 To 35 Kt After Midnight. Seas 10 To 13 Ft, Subsiding To 8 To 11 Ft After Midnight. Wave Detail: Se 13 Ft At 9 Seconds, Becoming Se 11 Ft At 10 Seconds. Showers. |
| Tue...W Winds 20 To 25 Kt With Gusts Up To 35 Kt. Seas 5 To 8 Ft. Wave Detail: Se 8 Ft At 10 Seconds And Nw 5 Ft At 4 Seconds. Scattered Flurries In The Afternoon. |
| Tue Night...Nw Winds 10 To 15 Kt With Gusts Up To 25 Kt. Seas 4 To 6 Ft. Wave Detail: Se 5 Ft At 10 Seconds And Nw 4 Ft At 5 Seconds. Scattered Flurries In The Evening. |
| Wed...N Winds 10 To 15 Kt, Becoming E 5 To 10 Kt In The Afternoon. Seas 3 To 5 Ft. Wave Detail: Se 4 Ft At 10 Seconds And Nw 2 Ft At 4 Seconds. |
| Wed Night...S Winds 5 To 10 Kt. Seas 3 To 4 Ft. Wave Detail: Se 4 Ft At 9 Seconds And N 1 Foot At 4 Seconds. |
| Thu...S Winds 5 To 10 Kt. Seas Around 3 Ft. |
| Thu Night...S Winds Around 5 Kt. Seas Around 3 Ft. |
| Fri...Sw Winds 5 To 10 Kt. Seas Around 3 Ft. |
| Fri Night...S Winds 5 To 10 Kt, Becoming Sw 10 To 15 Kt After Midnight. Seas 3 To 5 Ft. A Chance Of Rain After Midnight. Winds And Seas Higher In And Near Tstms. |
| Area Forecast Discussion National Weather Service Mount Holly NJ 327pm EDT Monday Mar 16 2026 .WHAT HAS CHANGED... Wind Advisory expanded inland to include all of the forecast area this afternoon into tonight. Gale Warning extended until 6am early Tuesday morning. .KEY MESSAGES... 1. We continue to monitor the potential for strong to severe thunderstorms this afternoon into tonight along and ahead of a strong cold front. Even outside of storms, strong winds are likely, especially closer to the coast. Localized flash flooding will also be possible, especially inland. 2. Some minor coastal flooding along the back bays with high tide this evening. 3. Cold and dry for the middle of the week, then temperatures moderate late this week and through this weekend. KEY MESSAGE 1...We continue to monitor the potential for strong to severe thunderstorms this afternoon into tonight along and ahead of a strong cold front. Even outside of storms, strong winds are likely, especially closer to the coast. Localized flash flooding will also be possible, especially inland. A strongly amplified upper level trough across the central CONUS will turn negatively tilted as we head toward evening. A strong mid latitude cyclone will continue to strengthen and move northeastward across the eastern Great Lakes and into southeastern Canada into tonight. This system will continue to push north towards James Bay in Quebec and will usher in a strong cold front with a sharp temperature gradient through the region late this evening. The warm sector of the cyclone has enveloped the region, with both warmer temperatures and higher dewpoints. The southerly flow associated with this system has brought a deep moisture plume into the region ahead of the frontal system. Significant height falls are occuring along with a strong upper level jet with the right rear located right over the Mid Atlantic. The combination of strong warm air advection, rapidly falling surface pressure, and upper level dynamics will result in significant forcing for ascent across the region through the evening. Low level wind shear is quite strong just ahead of the frontal passage and the combination of dynamic lift, sufficient moisture, and modest instability (for mid March standards) will support organized convection. Instability will be the limiting factor, however the dynamics should play a strong enough role in overcoming that instability. High res guidance show sufficient low level support to see STP values greater than 0.5-1 during a brief window during the late afternoon/evening. As of early this afternoon, a tornado watch is in effect across the entire CWA (County Warning Area) until early evening, and it may be extended as conditions warrant. Something to note, is that if the temperatures/dewpoints surge higher than initially forecast, instability will increase quite a bit. Guidance has a tendency to be too conservative with surface conditions in strong southerly flow regimes (as we will have during this event). Higher temperatures/dewpoints in the warm sector ahead of the cold front could support potential for some isolated supercells to develop. The primary threat remains wind, however the threat for tornadoes is increasing. Shear vectors are generally supportive of QLCS type tornadoes and these are often the hardest type of tornado to issue warnings for, as they can be very brief in nature. A potential limiting factor for this setup could be too much convection. If too much disorganized, benign convection occurs ahead of the line, it could weaken lapse rates and instability. But again, we'll have plenty of forcing and very strong wind fields to help recover the environment in the wake of such activity. Finally, it should be noted that even outside of any thunderstorms the strong wind fields will support southerly winds. A burst of strong westerly winds is also likely during and immediately after the cold frontal passage late this evening, with gusts up to 55 mph possible. Therefore, the Wind Advisory was expanded to include the entire forecast area. The strong southerly winds has ushered in an unseasonably warm and humid airmass. Temperatures this evening will be in the mid 60s to low 70s inland, and closer to 60 degrees near the coast and higher terrain. In addition to the severe weather and strong wind threat, the showers/storms will likely be producing heavy rainfall as PWATs (Precipitable Waters) are forecast to be 1.1-1.4" which is above the 90th percentile for early March. MMEFS guidance is showing modest rises in rivers, so we'll continue to watch for any potential hydro concerns, especially where any training of convection occurs. KEY MESSAGE 2...Some minor coastal flooding along the back bays with high tide this evening. South winds will continue to increase through this evening with gales developing by or just after sunset. This will keep water from draining out of Barnegat Bay, Rehoboth Bay, and Little Assawoman Bay, resulting in elevated tide levels and some minor coastal flooding around the high tide this evening. The most likely areas to experience impacts will be along the northern end of Barnegat Bay in Ocean County NJ, Rehoboth Bay and Little Assawoman Bay in Sussex County DE. These bays are particularly susecptible to flooding during strong southerly wind events, as the winds prevent water from draining normally during low tide. Thus, impacts may not follow typical astronomical tide cycles. These advisories are in effect through 2am Tuesday, however extensions may be needed if impacts linger after winds shift offshore. The Eastern Shore of Chesapeake Bay and upper portion of the tidal Delaware River (north of Philadelphia) could also experience some minor coastal flooding, though confidence is lower for these areas. Trends will continue to be monitored to determine if any additional advisories may be needed. KEY MESSAGE 3...Cold and dry for the middle of the week, then temperatures moderate late this week and through this weekend. Canadian high pressure will be centered over the southern Appalachians and Mid-Atlantic Tuesday night, then will lift to the northeast, with the center of the high passing over New Jersey on Wednesday. The high then lifts into the Canadian Maritimes Wednesday night through Thursday. A weak cold front will pass through the region Thursday night, followed by a stronger cold front Friday night. High pressure will mostly be over the area this weekend until another cold front potentially passes through the area Sunday night. Temperatures Tuesday night through Wednesday will more resemble that of January than mid-March with lows in the 20s and low 30s and highs in the upper 30s to low 40s. Thereafter, a much warmer airmass begins to build east with highs warming into the 40s and low 50s Thursday, then generally in the low to mid 50s north and west of the Fall Line and in the mid and upper 50s south and east of the Fall Line Friday through Sunday. With the passage of the first front Thursday night, generally 20 to 30 percent PoPs, mostly for rain, but some spotty freezing rain is possible for the southern Poconos. With the stronger front Friday night, Probability of Precipitation will generally be in the 30 to 50 percent range, again, mostly rain. Marine Gale Warning continues on the waters through tonight, may need extension into the day Tuesday. Southerly flow continues to increase, with gales likely by late day/evening just ahead of cold front. Then westerly winds likely produce gales along/just behind front for a few hours into the early morning Tuesday. Winds will relax a bit as we get into Tuesday but some lingering gale gusts may continue past dawn. Seas building thru this evening until peaking at 10-15 feet, then starting to slowly diminish late tonight through Tuesday. Outlook... Tuesday night...Gusty west winds diminish in the evening, but seas remain elevated. SCA (Small Craft Advisory) may continue to be needed. No significant weather. Wednesday through Friday...VFR. Sub-SCA (Small Craft Advisory) conditions. No significant weather. NOAA Mount Holly NJ Office: Watches - Warnings - Advisories PA...Wind Advisory until 2am EDT Tuesday for PAZ054-055-060>062- 070-071-101>106. NJ...Wind Advisory until 2am EDT Tuesday for NJZ001-007>010- 012>027. Coastal Flood Advisory until 2am EDT Tuesday for NJZ020-026. DE...Wind Advisory until 2am EDT Tuesday for DEZ001>004. Coastal Flood Advisory until 2am EDT Tuesday for DEZ003-004. MD...Wind Advisory until 2am EDT Tuesday for MDZ012-015-019-020. Marine Gale Warning until 6am EDT Tuesday for ANZ430-431-450>455. |
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