Alert archive / New Jersey / Special Marine Warnings in 2021

Special Marine Warning 101, NWS Philadelphia/Mount Holly

July 21, 2021

NWS Philadelphia/Mount Holly issued this special marine warning at Jul 21, 2021, 5:07 PM EDT. It was in force for 23 min. 4 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 21, 2021, 5:07 PM EDT (21:07 UTC)
Expired: Jul 21, 2021, 5:30 PM EDT
In force: 23 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 34.0 mph

The radar

The Dover AFB radar (KDOX), 48 km from the middle of the area, began a volume at 21:11 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.

What was reported inside it

Time	Report	Where	Remark
Jul 21, 5:32 PM EDT	TSTM WND DMG	Lower Township, NJ	TREE DOWN IN CAPE ROAD ROAD IN LOWER TOWNSHIP. TIME ESTIMATED FROM RADAR.
Jul 21, 5:33 PM EDT	TSTM WND GST 58	1 Ssw North Cape May, NJ	NOS SITE AT NORTH CAPE MAY MEASURES 58MPH GUST (TIME BETWEEN 5:30 AND 5:35 PM).
Jul 21, 5:36 PM EDT	TSTM WND DMG	1 Nnw Cape May Harbor, NJ	WIRES DOWN ON OCEAN DRIVE IN CAPE MAY. TIME ESTIMATED FROM RADAR.
Jul 21, 5:36 PM EDT	TSTM WND DMG	1 Sw Wildwood Crest, NJ	TELEPHONE POLE SNAPPED IN HALF ON W PRESTON AVE IN WILDWOOD CREST. PHOTO RELAYED ON SOCIAL MEDIA. TIME ESTIMATED FROM RADAR.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 9.1 hours before the alert went out and 128 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 728 J/kg
Mixed-layer CIN: -47 J/kg
Mixed-layer LCL: 1221 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: -10 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

As transmitted.

660 
WHUS51 KPHI 212107
SMWPHI
ANZ430-431-212130-
/O.NEW.KPHI.MA.W.0101.210721T2107Z-210721T2130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Mount Holly NJ
507 PM EDT Wed Jul 21 2021

The National Weather Service in Mount Holly NJ has issued a

* Special Marine Warning for...
  Delaware Bay...

* Until 530 PM EDT.

* At 507 PM EDT, a strong thunderstorm was located near Fourteen Foot
  Bank Light, moving east at 35 knots.

  HAZARD...Wind gusts 34 knots or greater and small hail.

  SOURCE...Radar.

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

* Locations impacted include...
  Brown Shoal Light, Fourteen Foot Bank Light, Miah Maull Light,
  Brandywine Shoal Light, Wildwood, Cape May Point, Sea Isle City and
  Slaughter Beach.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor until hazardous weather passes.

Report severe weather to the Coast Guard or the National Weather
Service.

&&

LAT...LON 3912 7535 3915 7470 3912 7471 3909 7471
      3902 7478 3903 7479 3903 7480 3899 7479
      3894 7486 3893 7491 3894 7497 3887 7504
      3895 7540
TIME...MOT...LOC 2107Z 282DEG 37KT 3902 7528 

HAIL...<.75IN
WIND...>34KTS

$$

MPS

1 follow-up statement

872 
FZUS71 KPHI 212121
MWSPHI

Marine Weather Statement
National Weather Service Mount Holly NJ
521 PM EDT Wed Jul 21 2021

ANZ430-431-212130-
/O.EXP.KPHI.MA.W.0101.000000T0000Z-210721T2130Z/
521 PM EDT Wed Jul 21 2021

...THE SPECIAL MARINE WARNING WILL EXPIRE AT 530 PM EDT...

The affected areas were... 
Delaware Bay...

There is another Special Marine Warning in effect for Delaware Bay.

A Severe Thunderstorm Watch remains in effect until 800 PM EDT for
central and southern Delaware...southern New Jersey...and the
adjacent coastal waters.

LAT...LON 3912 7535 3915 7470 3912 7471 3909 7471
      3902 7478 3903 7479 3903 7480 3899 7479
      3894 7486 3893 7491 3894 7497 3887 7504
      3895 7540
TIME...MOT...LOC 2120Z 282DEG 37KT 3899 7512 

$$

MPS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 11:09 AM EDT	Special Weather Statement	PHI	Morris	36 min
Jul 21, 12:41 PM EDT	Special Weather Statement	PHI	Ocean	34 min
Jul 21, 12:46 PM EDT	Special Marine Warning	PHI		89 min
Jul 21, 12:51 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Ocean	39 min
Jul 21, 12:53 PM EDT	Severe Thunderstorm Warning	PHI	Ocean	67 min
Jul 21, 1:28 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic	47 min
Jul 21, 1:43 PM EDT	Severe Thunderstorm Warning	PHI	Ocean	49 min
Jul 21, 2:10 PM EDT	Special Marine Warning	PHI		95 min
Jul 21, 2:13 PM EDT	Severe Thunderstorm Warning	PHI	Burlington	47 min
Jul 21, 2:35 PM EDT	Special Marine Warning	PHI		55 min
Jul 21, 2:52 PM EDT	Severe Thunderstorm Warning	PHI	Ocean	26 min
Jul 21, 3:04 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Gloucester	56 min
Jul 21, 3:16 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden	44 min
Jul 21, 3:27 PM EDT	Severe Thunderstorm Warning	PHI	Camden, Gloucester	33 min
Jul 21, 3:43 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	47 min
Jul 21, 3:48 PM EDT	Special Marine Warning	PHI		57 min
Jul 21, 3:48 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden	42 min
Jul 21, 3:57 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Gloucester, Salem	33 min
Jul 21, 4:04 PM EDT	Special Marine Warning	PHI		56 min
Jul 21, 4:17 PM EDT	Special Marine Warning	PHI		58 min
Jul 21, 4:50 PM EDT	Special Marine Warning	PHI		55 min
Jul 21, 5:09 PM EDT	Special Marine Warning	PHI		66 min
Jul 21, 5:24 PM EDT	Special Marine Warning	PHI		46 min
Jul 21, 5:31 PM EDT	Severe Thunderstorm Warning	PHI	Cape May	29 min
Jul 21, 5:52 PM EDT	Special Marine Warning	PHI		53 min
Jul 21, 1:08 PM EDT	Special Weather Statement	PHI	Lehigh	37 min
Jul 21, 1:11 PM EDT	Special Weather Statement	PHI	Northampton	34 min
Jul 21, 1:27 PM EDT	Severe Thunderstorm Warning	PHI	Berks	48 min
Jul 21, 2:03 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Northampton	42 min
Jul 21, 2:14 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Delaware, Montgomery	19 min
Jul 21, 2:41 PM EDT	Special Weather Statement	PHI	Montgomery	49 min
Jul 21, 2:48 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	42 min
Jul 21, 2:52 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	38 min
Jul 21, 5:59 PM EDT	Special Weather Statement	PHI	Berks	31 min
Jul 21, 4:50 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	25 min

Nearby

Special Marine Warnings in New Jersey, 2021 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.