Alert archive / New Jersey / Special Marine Warnings in 2025

Special Marine Warning 21, NWS Philadelphia/Mount Holly

April 26, 2025

NWS Philadelphia/Mount Holly issued this special marine warning at Apr 26, 2025, 7:56 PM EDT. It was in force for 64 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Apr 26, 2025, 7:56 PM EDT (23:56 UTC)
Expired
Apr 26, 2025, 9:00 PM EDT
In force
64 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
49.0 mph

The radar

The Dover AFB radar (KDOX), 55 km from the middle of the area, began a volume at 23:57 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 11.9 hours before the alert went out and 72 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Wallops Is Stn, VA at 12:00Z on 2025-04-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 266 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Wallops Is Stn, VA at 12:00Z on 2025-04-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 129 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
266 J/kg
Mixed-layer CIN
-62 J/kg
Mixed-layer LCL
921 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
129 m²/s²
0-3 km storm-relative helicity
110 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

267 
WHUS51 KPHI 262356
SMWPHI
ANZ455-475-270100-
/O.NEW.KPHI.MA.W.0021.250426T2356Z-250427T0100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Mount Holly NJ
756 PM EDT Sat Apr 26 2025

The National Weather Service in Mount Holly NJ has issued a

* Special Marine Warning for...
  Coastal waters from Cape Henlopen to Fenwick Island DE out 20 nm...
  Outer waters from Cape May NJ to Fenwick Island DE out 20 to 40
  nm...

* Until 900 PM EDT.

* At 756 PM EDT, a strong thunderstorm was located 11 nm west of
  Bethany Beach, moving east at 35 knots.

  HAZARD...Wind gusts to nearly 50 knots and small hail.

  SOURCE...Radar.

  IMPACT...Small craft could be damaged in briefly higher winds and 
           suddenly higher waves.

* Locations impacted include...
  Bethany Beach, Fenwick Island, Delaware Lightship Buoy 44009, and
  Indian River Inlet Bridge.

LAT...LON 3832 7464 3845 7503 3845 7510 3851 7511
      3853 7515 3851 7523 3856 7533 3860 7534
      3861 7534 3865 7437 3830 7441
TIME...MOT...LOC 2356Z 273DEG 36KT 3849 7530 

HAIL...<.75IN
WIND...49KTS

$$

RCM
3 follow-up statements
286 
FZUS71 KPHI 270023
MWSPHI

Marine Weather Statement
National Weather Service Mount Holly NJ
823 PM EDT Sat Apr 26 2025

ANZ455-475-270100-
/O.CON.KPHI.MA.W.0021.000000T0000Z-250427T0100Z/
823 PM EDT Sat Apr 26 2025

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 900 PM EDT...

For the following areas...
Coastal waters from Cape Henlopen to Fenwick Island DE out 20 nm...
Waters from Cape May NJ to Fenwick Island DE out 20 to 40 nm...

At 823 PM EDT, a strong thunderstorm was located near Fenwick Island,
moving east at 35 knots.

HAZARD...Wind gusts to nearly 50 knots and small hail.

SOURCE...Radar indicated.

IMPACT...Small craft could be damaged in briefly higher winds and 
         suddenly higher waves.

Locations impacted include...
Bethany Beach, Fenwick Island, Delaware Lightship Buoy 44009, and
Indian River Inlet Bridge.

LAT...LON 3832 7462 3845 7503 3845 7510 3851 7511
      3853 7515 3861 7516 3865 7437 3830 7441
TIME...MOT...LOC 0023Z 273DEG 36KT 3847 7495 

HAIL...<.75IN
WIND...49KTS

$$

RCM
402 
FZUS71 KPHI 270030
MWSPHI

Marine Weather Statement
National Weather Service Mount Holly NJ
830 PM EDT Sat Apr 26 2025

ANZ455-475-270100-
/O.CON.KPHI.MA.W.0021.000000T0000Z-250427T0100Z/
830 PM EDT Sat Apr 26 2025

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 900 PM EDT...

For the following areas...
Coastal waters from Cape Henlopen to Fenwick Island DE out 20 nm...
Waters from Cape May NJ to Fenwick Island DE out 20 to 40 nm...

At 830 PM EDT, a strong thunderstorm was located 7 nm west of
Delaware Lightship Buoy 44009, moving east at 35 knots.

HAZARD...Wind gusts to nearly 50 knots and small hail.

SOURCE...Radar indicated.

IMPACT...Small craft could be damaged in briefly higher winds and 
         suddenly higher waves.

Locations impacted include...
Delaware Lightship Buoy 44009.

LAT...LON 3832 7462 3845 7503 3851 7502 3854 7503
      3861 7504 3865 7437 3830 7441
TIME...MOT...LOC 0030Z 273DEG 36KT 3847 7486 

HAIL...<.75IN
WIND...49KTS

$$

RCM
626 
FZUS71 KPHI 270053
MWSPHI

Marine Weather Statement
National Weather Service Mount Holly NJ
853 PM EDT Sat Apr 26 2025

ANZ455-475-270102-
/O.EXP.KPHI.MA.W.0021.000000T0000Z-250427T0100Z/
853 PM EDT Sat Apr 26 2025

...THE SPECIAL MARINE WARNING WILL EXPIRE AT 900 PM EDT...

The affected areas were... 
Coastal waters from Cape Henlopen to Fenwick Island DE out 20 nm...

The thunderstorm is moving out of the area and will soon pose no 
further significant threat to boaters.

LAT...LON 3832 7462 3845 7503 3851 7502 3854 7503
      3861 7504 3865 7437 3830 7441
TIME...MOT...LOC 0052Z 273DEG 36KT 3846 7463 

$$

RCM

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 26, 12:43 PM EDTSpecial Marine WarningPHI29 min
Apr 26, 4:36 PM EDTSpecial Marine WarningPHI54 min
Apr 26, 5:12 PM EDTSpecial Marine WarningPHI68 min
Apr 26, 5:16 PM EDTSevere Thunderstorm WarningPHIOcean27 min
Apr 26, 5:29 PM EDTTornado WarningPHIOcean14 min
Apr 26, 5:48 PM EDTSpecial Marine WarningPHI58 min
Apr 26, 3:48 PM EDTSevere Thunderstorm WarningPHIKent42 min
Apr 26, 7:55 PM EDTSevere Thunderstorm WarningPHISussex34 min

Nearby

Special Marine Warnings in New Jersey, 2025Every special marine warning in 2025

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.