Alert archive / New Jersey / Special Marine Warnings in 2021

Special Marine Warning 85, NWS Philadelphia/Mount Holly

July 12, 2021

NWS Philadelphia/Mount Holly issued this special marine warning at Jul 12, 2021, 7:33 PM EDT. It was in force for 58 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: Jul 12, 2021, 7:33 PM EDT (23:33 UTC)
Expired: Jul 12, 2021, 8:31 PM EDT
In force: 58 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), 78 km from the middle of the area, began a volume at 23:35 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, 11.6 hours before the alert went out and 178 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: 1012 J/kg
Mixed-layer CIN: -81 J/kg
Mixed-layer LCL: 930 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 55 m²/s²
0-3 km storm-relative helicity: 72 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

As transmitted.

700 
WHUS51 KPHI 122333
SMWPHI
ANZ430-130100-
/O.NEW.KPHI.MA.W.0085.210712T2333Z-210713T0100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Mount Holly NJ
733 PM EDT Mon Jul 12 2021

The National Weather Service in Mount Holly NJ has issued a

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

* Until 900 PM EDT.

* At 733 PM EDT, a strong thunderstorm was located near Pea Patch
  Island. The strong thunderstorm was nearly stationary.

  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...
  Pea Patch Island, Stony Point and Reedy Point. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor until hazardous weather passes.

&&

LAT...LON 3968 7562 3973 7558 3976 7553 3974 7545
      3969 7544 3961 7534 3951 7539 3948 7533
      3943 7534 3943 7529 3946 7525 3946 7522
      3939 7516 3937 7518 3936 7518 3935 7533
      3939 7559 3948 7562
TIME...MOT...LOC 2333Z 321DEG 2KT 3968 7553 

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

$$

Staarmann

1 follow-up statement

412 
FZUS71 KPHI 130031
MWSPHI

Marine Weather Statement
National Weather Service Mount Holly NJ
831 PM EDT Mon Jul 12 2021

ANZ430-130040-
/O.CAN.KPHI.MA.W.0085.000000T0000Z-210713T0100Z/
831 PM EDT Mon Jul 12 2021

...THE SPECIAL MARINE WARNING IS CANCELLED...

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

The thunderstorm has weakened and no longer poses a significant
threat to boaters.

A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
northern Delaware...southern New Jersey...and the adjacent coastal
waters.

LAT...LON 3968 7562 3973 7558 3976 7553 3974 7545
      3969 7544 3961 7534 3951 7539 3948 7533
      3943 7534 3943 7529 3946 7525 3946 7522
      3939 7516 3937 7518 3936 7518 3935 7533
      3939 7559 3948 7562
TIME...MOT...LOC 0029Z 321DEG 2KT 3965 7550 

$$

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 1:59 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden	3 hr
Jul 12, 2:12 PM EDT	Flash Flood Warning Emergency	PHI	Burlington	7 hr
Jul 12, 2:20 PM EDT	Areal Flood Advisory	PHI	Mercer, Middlesex, Monmouth	3 hr
Jul 12, 2:37 PM EDT	Flash Flood Warning	PHI	Mercer, Middlesex, Monmouth	93 min
Jul 12, 3:08 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Middlesex, Monmouth, Ocean	67 min
Jul 12, 3:31 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Monmouth	41 min
Jul 12, 4:26 PM EDT	Special Marine Warning	PHI		2 hr
Jul 12, 4:33 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	42 min
Jul 12, 4:52 PM EDT	Areal Flood Advisory	PHI	Monmouth, Ocean	98 min
Jul 12, 5:08 PM EDT	Areal Flood Advisory	PHI	Sussex	5 hr
Jul 12, 5:08 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Mercer	67 min
Jul 12, 5:26 PM EDT	Areal Flood Advisory	PHI	Camden	2 hr
Jul 12, 5:36 PM EDT	Special Weather Statement	PHI	Sussex	24 min
Jul 12, 5:41 PM EDT	Areal Flood Advisory	PHI	Burlington	83 min
Jul 12, 5:57 PM EDT	Severe Thunderstorm Warning	PHI	Morris, Sussex	63 min
Jul 12, 6:01 PM EDT	Flash Flood Warning	PHI	Camden	102 min
Jul 12, 6:08 PM EDT	Areal Flood Advisory	PHI	Morris	98 min
Jul 12, 6:43 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester	93 min
Jul 12, 6:52 PM EDT	Severe Thunderstorm Warning	PHI	Morris, Sussex	34 min
Jul 12, 7:00 PM EDT	Areal Flood Advisory	PHI	Gloucester, Salem	112 min
Jul 12, 7:06 PM EDT	Severe Thunderstorm Warning	PHI	Salem	69 min
Jul 12, 7:11 PM EDT	Flash Flood Warning	PHI	Morris, Sussex	35 min
Jul 11, 10:21 PM EDT	Severe Thunderstorm Warning	PHI	Berks	24 min
Jul 11, 10:22 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	38 min
Jul 12, 2:28 PM EDT	Areal Flood Advisory	PHI	Chester	3 hr
Jul 12, 4:16 PM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery, Philadelphia	114 min
Jul 12, 5:41 PM EDT	Severe Thunderstorm Warning	PHI	Chester	34 min
Jul 12, 6:18 PM EDT	Flash Flood Warning	PHI	Delaware	84 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.