Alert archive / New Jersey / Special Marine Warnings in 2021

Special Marine Warning 49, NWS Philadelphia/Mount Holly

June 21, 2021

NWS Philadelphia/Mount Holly issued this special marine warning at Jun 21, 2021, 7:24 PM EDT. It was in force for 66 min. 1 report 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: Jun 21, 2021, 7:24 PM EDT (23:24 UTC)
Expired: Jun 21, 2021, 8:30 PM EDT
In force: 66 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.0 in
Wind: 49.0 mph

The radar

The Dover AFB radar (KDOX), 35 km from the middle of the area, began a volume at 23:27 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
Jun 21, 7:27 PM EDT	MARINE TSTM WIND 52	4 Ssw Elsinboro Twp, NJ

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, 11.4 hours before the alert went out and 132 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: 525 J/kg
Mixed-layer CIN: -38 J/kg
Mixed-layer LCL: 630 m above ground
0-6 km bulk shear: 7 kt
0-1 km storm-relative helicity: 4 m²/s²
0-3 km storm-relative helicity: -14 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

361 
WHUS51 KPHI 212324
SMWPHI
ANZ430-431-220030-
/O.NEW.KPHI.MA.W.0049.210621T2324Z-210622T0030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Mount Holly NJ
724 PM EDT Mon Jun 21 2021

The National Weather Service in Mount Holly NJ has issued a

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

* Until 830 PM EDT.

* At 723 PM EDT, strong thunderstorms were located along a line
  extending from 6 nm north of Pea Patch Island to 9 nm southwest of 
  Stony Point to 17 nm east of Chester River, moving east at 45 
  knots.

  HAZARD...Wind gusts to nearly 50 knots.

  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, Slaughter Beach, Cape
  Henlopen, East Point, Bowers Beach, Woodland Beach, Stony Point,
  Cape May Point, Miah Maull Light, Ship John Shoal Light, Brandywine
  Shoal Light, Reedy Point, Fortesque Beach, Sea Breeze, Pea Patch
  Island, Cross Ledge Light and Rehoboth Beach.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3968 7562 3969 7560 3945 7536 3926 7512
      3910 7480 3893 7495 3893 7498 3881 7509
      3877 7508 3874 7511 3880 7530 3884 7529
      3894 7541 3899 7539 3903 7546 3918 7547
      3923 7561
TIME...MOT...LOC 2323Z 268DEG 54KT 3969 7560 3936 7569 3905 7585 

HAIL...0.00IN
WIND...49KTS

$$

Fitzsimmons

1 follow-up statement

923 
FZUS71 KPHI 220004
MWSPHI

Marine Weather Statement
National Weather Service Mount Holly NJ
804 PM EDT Mon Jun 21 2021

ANZ430-431-220030-
/O.CON.KPHI.MA.W.0049.000000T0000Z-210622T0030Z/
804 PM EDT Mon Jun 21 2021

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 830 PM EDT...

For the following areas...
Delaware Bay waters north of East Point NJ to Slaughter Beach DE...
Delaware Bay waters south of East Point NJ to Slaughter Beach DE...

At 804 PM EDT, strong thunderstorms were located along a line
extending from 13 nm northeast of Sea Breeze to near Cross Ledge
Light to 16 nm west of Bowers Beach, moving southeast at 35 knots.

HAZARD...Wind gusts to 40 knots.

SOURCE...Radar indicated.

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

Locations impacted include...
Brown Shoal Light, Fourteen Foot Bank Light, Slaughter Beach, Cape
Henlopen, East Point, Bowers Beach, Woodland Beach, Stony Point, Cape
May Point, Miah Maull Light, Ship John Shoal Light, Brandywine Shoal
Light, Fortesque Beach, Sea Breeze, Cross Ledge Light and Rehoboth
Beach.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3946 7561 3951 7544 3926 7512 3910 7480
      3894 7494 3892 7500 3880 7509 3877 7508
      3874 7511 3880 7529 3884 7529 3894 7541
      3899 7539 3903 7546 3918 7547 3924 7561
      3928 7560 3930 7554 3940 7562
TIME...MOT...LOC 0004Z 301DEG 35KT 3946 7508 3923 7535 3896 7573 

HAIL...0.00IN
WIND...40KTS

$$

Fitzsimmons

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 21, 4:35 AM EDT	Heat Advisory	PHI	Burlington, Camden, Gloucester, Mercer	15 hr
Jun 21, 7:12 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Cumberland, Gloucester, Salem	48 min
Jun 21, 7:38 PM EDT	Severe Thunderstorm Warning	PHI	Warren	52 min
Jun 21, 7:43 PM EDT	Severe Thunderstorm Warning	PHI	Cumberland, Salem	47 min
Jun 21, 7:55 PM EDT	Special Weather Statement	PHI	Atlantic, Burlington, Camden, Mercer, Ocean	50 min
Jun 20, 9:27 PM EDT	Special Weather Statement	PHI	Schuylkill	33 min
Jun 20, 9:55 PM EDT	Special Weather Statement	PHI	Lebanon	35 min
Jun 20, 10:04 PM EDT	Areal Flood Advisory	PHI	Berks	86 min
Jun 20, 10:27 PM EDT	Special Weather Statement	PHI	Berks	33 min
Jun 21, 6:08 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	52 min
Jun 21, 6:21 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	54 min
Jun 21, 7:02 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Carbon, Lehigh, Northampton	43 min
Jun 21, 6:47 PM EDT	Severe Thunderstorm Warning	PHI	Kent, New Castle	58 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.