Alert archive / New Jersey / Special Marine Warnings in 2021
Special Marine Warning 12, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this special marine warning at May 4, 2021, 7:54 PM EDT. It was in force for 51 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
- May 4, 2021, 7:54 PM EDT (23:54 UTC)
- Expired
- May 4, 2021, 8:45 PM EDT
- In force
- 51 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Hail
- 0.0 in
- Wind
- 34.0 mph
The radar
The Dover AFB radar (KDOX), 32 km from the middle of the area, began a volume at 23:58 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 115 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.
- Mixed-layer CAPE
- 60 J/kg
- Mixed-layer CIN
- -270 J/kg
- Mixed-layer LCL
- 1140 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 46 m²/s²
- 0-3 km storm-relative helicity
- 96 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
962
WHUS51 KPHI 042354
SMWPHI
ANZ431-453-454-050045-
/O.NEW.KPHI.MA.W.0012.210504T2354Z-210505T0045Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Mount Holly NJ
754 PM EDT Tue May 4 2021
The National Weather Service in Mount Holly NJ has issued a
* Special Marine Warning for...
Lower Delaware Bay...
Coastal waters from Great Egg Inlet NJ to Cape Henlopen DE out 20
nm...
* Until 845 PM EDT.
* At 754 PM EDT, a strong thunderstorm was located near Slaughter
Beach, moving northeast at 35 knots.
HAZARD...Wind gusts 34 knots or greater.
SOURCE...Radar.
IMPACT...Small craft could be damaged in briefly higher winds and
suddenly higher waves.
* Locations impacted include...
Overfalls Shoal, Brown Shoal Light, Fourteen Foot Bank Light,
Slaughter Beach, Cape Henlopen, East Point, Cape May Point,
Brandywine Shoal Light and Wildwood.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Protecting yourself from immediate threats to life and safety shall
take priority. Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.
Move to safe harbor until hazardous weather passes.
&&
LAT...LON 3928 7499 3924 7494 3923 7495 3922 7492
3899 7466 3879 7506 3880 7509 3877 7509
3870 7523 3872 7524 3875 7520 3876 7530
3879 7531 3883 7529 3888 7534
TIME...MOT...LOC 2354Z 229DEG 36KT 3882 7525
HAIL...0.00IN
WIND...>34KTS
$$
Meola2 follow-up statements
857
FZUS71 KPHI 050024
MWSPHI
Marine Weather Statement
National Weather Service Mount Holly NJ
824 PM EDT Tue May 4 2021
ANZ431-453-454-050045-
/O.CON.KPHI.MA.W.0012.000000T0000Z-210505T0045Z/
824 PM EDT Tue May 4 2021
...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 845 PM EDT...
For the following areas...
Coastal waters from Cape May NJ to Cape Henlopen DE out 20 nm...
Coastal waters from Great Egg Inlet to Cape May NJ out 20 nm...
Delaware Bay waters south of East Point NJ to Slaughter Beach DE...
At 823 PM EDT, a strong thunderstorm was located near Cape May Point,
moving northeast at 35 knots.
HAZARD...Wind gusts 34 knots or greater.
SOURCE...Radar indicated.
IMPACT...Small craft could be damaged in briefly higher winds and
suddenly higher waves.
Locations impacted include...
Overfalls Shoal, Cape May Point and Wildwood.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Protecting yourself from immediate threats to life and safety shall
take priority. Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.
Move to safe harbor until hazardous weather passes.
&&
LAT...LON 3918 7490 3912 7480 3899 7466 3879 7506
3891 7506 3904 7509
TIME...MOT...LOC 0023Z 241DEG 35KT 3896 7490
HAIL...0.00IN
WIND...>34KTS
$$
Meola609
FZUS71 KPHI 050038
MWSPHI
Marine Weather Statement
National Weather Service Mount Holly NJ
838 PM EDT Tue May 4 2021
ANZ431-453-454-050048-
/O.EXP.KPHI.MA.W.0012.000000T0000Z-210505T0045Z/
838 PM EDT Tue May 4 2021
...THE SPECIAL MARINE WARNING WILL EXPIRE AT 845 PM EDT...
The affected areas were...
Lower Delaware Bay...
Coastal waters from Great Egg Inlet NJ to Cape Henlopen DE out 20
nm...
The thunderstorm has weakened and no longer poses a significant
threat to boaters.
LAT...LON 3918 7490 3912 7480 3899 7466 3879 7506
3891 7506 3904 7509
TIME...MOT...LOC 0038Z 224DEG 36KT 3900 7472
$$
MeolaThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 4, 7:04 PM EDT | Severe Thunderstorm Warning | PHI | Kent, Sussex | 41 min |
| May 4, 7:38 PM EDT | Severe Thunderstorm Warning | PHI | Kent, Sussex | 31 min |
| May 4, 7:43 PM EDT | Special Weather Statement | PHI | Sussex | 47 min |
Nearby
Special Marine Warnings in New Jersey, 2021Every special marine warning in 2021
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.