Alert archive / New Jersey / Special Marine Warnings in 2021

Special Marine Warning 61, NWS Philadelphia/Mount Holly

July 1, 2021

NWS Philadelphia/Mount Holly issued this special marine warning at Jul 1, 2021, 4:21 PM EDT. It was in force for 114 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: Jul 1, 2021, 4:21 PM EDT (20:21 UTC)
Expired: Jul 1, 2021, 6:15 PM EDT
In force: 114 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 50.0 mph

The radar

The Dover AFB radar (KDOX), 50 km from the middle of the area, began a volume at 20:24 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 1, 5:30 PM EDT	MARINE TSTM WIND 52	1 Ssw North Cape May, NJ	NOS GAUGE CMAN4.

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, 8.4 hours before the alert went out and 149 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: 1445 J/kg
Mixed-layer CIN: -95 J/kg
Mixed-layer LCL: 981 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 29 m²/s²
0-3 km storm-relative helicity: 31 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

926 
WHUS51 KPHI 012021
SMWPHI
ANZ430-431-012215-
/O.NEW.KPHI.MA.W.0061.210701T2021Z-210701T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Mount Holly NJ
421 PM EDT Thu Jul 1 2021

The National Weather Service in Mount Holly NJ has issued a

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

* Until 615 PM EDT.

* At 420 PM EDT, a severe thunderstorm was located 14 nm west of 
  Bowers Beach, moving east at 25 knots. Additional severe storms 
  will likely move through the bay thereafter.

  HAZARD...Wind gusts in excess of 50 knots and small hail.

  SOURCE...Radar.

  IMPACT...Boats could suffer significant structural damage in high 
           winds. Small craft could capsize in 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,
  Miah Maull Light, Ship John Shoal Light, Brandywine Shoal Light,
  Reedy Point, Fortesque Beach, Sea Breeze, Pea Patch Island, Cross
  Ledge Light, Cape May Point and Rehoboth Beach.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor immediately as gusty winds and high waves are
expected.

&&

LAT...LON 3968 7562 3971 7558 3974 7558 3974 7545
      3943 7540 3930 7512 3927 7513 3927 7506
      3914 7479 3893 7493 3894 7497 3881 7509
      3872 7508 3896 7540 3899 7539 3902 7544
      3927 7548 3946 7561
TIME...MOT...LOC 2020Z 256DEG 27KT 3912 7570 

HAIL...<.75IN
WIND...50KTS

$$

CMS

2 follow-up statements

697 
FZUS71 KPHI 012106
MWSPHI

Marine Weather Statement
National Weather Service Mount Holly NJ
506 PM EDT Thu Jul 1 2021

ANZ430-431-012215-
/O.CON.KPHI.MA.W.0061.000000T0000Z-210701T2215Z/
506 PM EDT Thu Jul 1 2021

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 615 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 505 PM EDT, a severe thunderstorm capable of producing waterspouts
was located over Slaughter Beach, moving east at 35 knots.

HAZARD...Waterspouts, wind gusts in excess of 50 knots, and small 
         hail. There is a very strong indication of a tornado near 
         Slaughter Beach.

SOURCE...Radar indicated.

IMPACT...Waterspouts can easily overturn boats and create locally 
         hazardous seas. Boats could suffer significant structural 
         damage in high winds. Small craft could capsize in 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, Miah
Maull Light, Ship John Shoal Light, Brandywine Shoal Light, Reedy
Point, Fortesque Beach, Sea Breeze, Pea Patch Island, Cross Ledge
Light, Cape May Point and Rehoboth Beach.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor immediately as gusty winds and high waves are
expected.

&&

LAT...LON 3968 7562 3971 7558 3974 7558 3974 7545
      3943 7540 3930 7512 3927 7513 3927 7506
      3914 7479 3893 7493 3894 7497 3881 7509
      3872 7508 3896 7540 3899 7539 3902 7544
      3927 7548 3946 7561
TIME...MOT...LOC 2105Z 261DEG 33KT 3892 7531 

WATERSPOUT...POSSIBLE
HAIL...<.75IN
WIND...50KTS

$$

CMS

991 
FZUS71 KPHI 012206
MWSPHI

Marine Weather Statement
National Weather Service Mount Holly NJ
606 PM EDT Thu Jul 1 2021

ANZ430-431-012215-
/O.EXP.KPHI.MA.W.0061.000000T0000Z-210701T2215Z/
606 PM EDT Thu Jul 1 2021

...THE SPECIAL MARINE WARNING WILL EXPIRE AT 615 PM EDT...

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

The thunderstorm has moved out of the area and no longer poses a
significant threat to boaters.

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 3968 7562 3971 7558 3974 7558 3974 7545
      3943 7540 3930 7512 3927 7513 3927 7506
      3914 7479 3893 7493 3894 7497 3881 7509
      3872 7508 3896 7540 3899 7539 3902 7544
      3927 7548 3946 7561
TIME...MOT...LOC 2205Z 256DEG 27KT 3903 7475 

$$

Robertson

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 30, 8:37 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer	38 min
Jun 30, 8:56 PM EDT	Special Marine Warning	PHI		94 min
Jun 30, 9:05 PM EDT	Special Weather Statement	PHI	Somerset	40 min
Jun 30, 9:21 PM EDT	Special Weather Statement	PHI	Salem	39 min
Jun 30, 9:49 PM EDT	Special Weather Statement	PHI	Monmouth	26 min
Jun 30, 9:51 PM EDT	Special Marine Warning	PHI		60 min
Jul 1, 2:58 AM EDT	Small Craft Advisory	PHI		17 hr
Jul 1, 1:10 PM EDT	Special Weather Statement	PHI	Monmouth	50 min
Jul 1, 1:16 PM EDT	Special Weather Statement	PHI	Atlantic	29 min
Jul 1, 1:28 PM EDT	Special Marine Warning	PHI		62 min
Jul 1, 1:31 PM EDT	Special Weather Statement	PHI	Cumberland	29 min
Jul 1, 4:27 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Gloucester, Hunterdon, Mercer, Salem and 1 more	48 min
Jul 1, 4:55 PM EDT	Severe Thunderstorm Warning	PHI	Cape May, Cumberland, Salem	80 min
Jul 1, 4:59 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Gloucester, Mercer, Middlesex, Monmouth and 2 more	46 min
Jul 1, 5:02 PM EDT	Tornado Warning	PHI	Burlington, Mercer	28 min
Jul 1, 5:27 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 5 more	93 min
Jul 1, 5:35 PM EDT	Tornado Warning	PHI	Mercer, Monmouth, Ocean	25 min
Jul 1, 5:40 PM EDT	Special Marine Warning	PHI		65 min
Jul 1, 5:46 PM EDT	Special Marine Warning	PHI		119 min
Jul 1, 6:13 PM EDT	Special Marine Warning	PHI		92 min
Jun 30, 8:16 PM EDT	Special Weather Statement	PHI	Bucks, Montgomery	44 min
Jul 1, 2:51 PM EDT	Special Weather Statement	PHI	Chester, Montgomery	39 min
Jul 1, 3:13 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery	47 min
Jul 1, 3:23 PM EDT	Areal Flood Advisory	PHI	Chester, Montgomery	77 min
Jul 1, 3:48 PM EDT	Areal Flood Advisory	PHI	Bucks, Delaware, Montgomery, Philadelphia	112 min
Jul 1, 3:50 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	40 min
Jul 1, 4:08 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	52 min
Jul 1, 4:08 PM EDT	Severe Thunderstorm Warning	PHI	Kent	52 min
Jul 1, 4:10 PM EDT	Areal Flood Advisory	PHI	Kent, New Castle	94 min
Jul 1, 4:32 PM EDT	Severe Thunderstorm Warning	PHI	Kent, New Castle, Sussex	43 min
Jul 1, 4:57 PM EDT	Tornado Warning	PHI	Kent, Sussex	22 min
Jul 1, 5:12 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	48 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.