Alert archive / New Jersey / Special Marine Warnings in 2021

Special Marine Warning 92, NWS Philadelphia/Mount Holly

July 17, 2021

NWS Philadelphia/Mount Holly issued this special marine warning at Jul 17, 2021, 10:51 PM EDT. It was in force for 114 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 17, 2021, 10:51 PM EDT (02:51 UTC)
Expired
Jul 18, 2021, 12:45 AM EDT
In force
114 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
40.0 mph

The radar

The Dover AFB radar (KDOX), 57 km from the middle of the area, began a volume at 02:50 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 00:00Z, 2.9 hours before the alert went out and 151 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-pSkew-T log-p diagram, Wallops Is Stn, VA at 00:00Z on 2021-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1997 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Wallops Is Stn, VA at 00:00Z on 2021-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 59 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
1997 J/kg
Mixed-layer CIN
-29 J/kg
Mixed-layer LCL
1118 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
59 m²/s²
0-3 km storm-relative helicity
74 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

010 
WHUS51 KPHI 180251
SMWPHI
ANZ430-431-180445-
/O.NEW.KPHI.MA.W.0092.210718T0251Z-210718T0445Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Mount Holly NJ
1051 PM EDT Sat Jul 17 2021

The National Weather Service in Mount Holly NJ has issued a

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

* Until 1245 AM EDT.

* At 1051 PM EDT, strong thunderstorms were located along a line
  extending from Ship John Shoal Light to 12 nm west of Bowers Beach,
  moving east at 15 knots.

  HAZARD...Wind gusts to 40 knots and small hail.

  SOURCE...Radar.

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

* Locations impacted include...
  Fortesque Beach, Sea Breeze, Fourteen Foot Bank Light, Slaughter
  Beach, East Point, Bowers Beach, Woodland Beach, Miah Maull Light,
  Ship John Shoal Light, Brandywine Shoal Light and Cross Ledge
  Light.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor until hazardous weather passes.

&&

LAT...LON 3941 7542 3941 7518 3927 7513 3926 7507
      3941 7509 3941 7499 3932 7492 3937 7478
      3941 7478 3941 7465 3926 7479 3931 7492
      3923 7495 3919 7486 3880 7525 3893 7540
      3899 7539 3922 7549 3930 7551
TIME...MOT...LOC 0251Z 258DEG 17KT 3929 7540 3908 7567 

HAIL...<.75IN
WIND...40KTS

$$

Staarmann
3 follow-up statements
188 
FZUS71 KPHI 180315
MWSPHI

Marine Weather Statement
National Weather Service Mount Holly NJ
1115 PM EDT Sat Jul 17 2021

ANZ430-431-180445-
/O.CON.KPHI.MA.W.0092.000000T0000Z-210718T0445Z/
1115 PM EDT Sat Jul 17 2021

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 1245 AM 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 1115 PM EDT, strong thunderstorms were located along a line
extending from near Sea Breeze to near Cross Ledge Light to near
Slaughter Beach, moving east at 20 knots.

HAZARD...Wind gusts to 40 knots and small hail.

SOURCE...Radar indicated.

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

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor until hazardous weather passes.

&&

LAT...LON 3941 7542 3941 7518 3927 7513 3926 7507
      3941 7509 3941 7499 3932 7492 3937 7478
      3941 7478 3941 7465 3926 7479 3931 7492
      3923 7495 3919 7486 3880 7525 3893 7540
      3899 7539 3922 7549 3930 7551
TIME...MOT...LOC 0315Z 267DEG 18KT 3931 7526 3915 7536 3892 7538 

HAIL...<.75IN
WIND...40KTS

$$

Staarmann
748 
FZUS71 KPHI 180328
MWSPHI

Marine Weather Statement
National Weather Service Mount Holly NJ
1128 PM EDT Sat Jul 17 2021

ANZ430-431-180445-
/O.CON.KPHI.MA.W.0092.000000T0000Z-210718T0445Z/
1128 PM EDT Sat Jul 17 2021

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 1245 AM 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 1128 PM EDT, strong thunderstorms were located along a line
extending from near Sea Breeze to Cross Ledge Light to Slaughter
Beach, moving east at 15 knots.

HAZARD...Wind gusts to 40 knots and small hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Fortesque Beach, Sea Breeze, Fourteen Foot Bank Light, Slaughter
Beach, East Point, Miah Maull Light, Brandywine Shoal Light and Cross
Ledge Light.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor until hazardous weather passes.

&&

LAT...LON 3939 7537 3941 7518 3935 7518 3927 7513
      3926 7507 3930 7506 3941 7509 3941 7499
      3932 7492 3937 7478 3941 7478 3941 7465
      3926 7479 3930 7485 3931 7492 3923 7495
      3919 7486 3880 7525 3893 7540
TIME...MOT...LOC 0328Z 257DEG 17KT 3932 7524 3916 7529 3893 7531 

HAIL...<.75IN
WIND...40KTS

$$

Staarmann
741 
FZUS71 KPHI 180353
MWSPHI

Marine Weather Statement
National Weather Service Mount Holly NJ
1153 PM EDT Sat Jul 17 2021

ANZ430-431-180445-
/O.CON.KPHI.MA.W.0092.000000T0000Z-210718T0445Z/
1153 PM EDT Sat Jul 17 2021

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 1245 AM 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 1153 PM EDT, strong thunderstorms were located along a line
extending from 9 nm northeast of Fortesque Beach to East Point to
near Slaughter Beach, moving east at 20 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...
Fortesque Beach, Miah Maull Light, Brandywine Shoal Light, Fourteen
Foot Bank Light, Slaughter Beach and East Point.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor until hazardous weather passes.

&&

LAT...LON 3935 7518 3927 7513 3926 7507 3930 7506
      3941 7509 3941 7499 3932 7492 3937 7478
      3941 7478 3941 7465 3926 7479 3931 7485
      3931 7492 3923 7495 3919 7486 3880 7525
      3895 7535
TIME...MOT...LOC 0353Z 260DEG 19KT 3933 7500 3917 7505 3891 7523 

HAIL...0.00IN
WIND...>34KTS

$$

Staarmann

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 17, 8:00 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Mercer, Monmouth45 min
Jul 17, 8:09 PM EDTFlash Flood WarningPHIMercer, Somerset4 hr
Jul 17, 8:35 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Camden, Gloucester40 min
Jul 17, 8:36 PM EDTSevere Thunderstorm WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean, Somerset54 min
Jul 17, 8:46 PM EDTSpecial Marine WarningPHI59 min
Jul 17, 8:53 PM EDTAreal Flood AdvisoryPHIMercer, Middlesex, Monmouth3 hr
Jul 17, 9:25 PM EDTAreal Flood AdvisoryPHIBurlington, Camden, Gloucester, Salem2 hr
Jul 17, 9:27 PM EDTSevere Thunderstorm WarningPHIGloucester, Salem48 min
Jul 17, 9:30 PM EDTSevere Thunderstorm WarningPHICape May29 min
Jul 17, 9:36 PM EDTFlash Flood WarningPHICamden, Gloucester, Salem2 hr
Jul 17, 9:44 PM EDTSpecial Marine WarningPHI61 min
Jul 17, 9:48 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Gloucester, Mercer, Salem42 min
Jul 17, 10:21 PM EDTSevere Thunderstorm WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean54 min
Jul 17, 10:22 PM EDTTornado WarningPHIBurlington, Monmouth, Ocean23 min
Jul 17, 10:27 PM EDTSpecial Weather StatementPHIBurlington, Camden33 min
Jul 17, 10:38 PM EDTTornado WarningPHIBurlington, Monmouth, Ocean16 min
Jul 17, 10:43 PM EDTFlash Flood WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean79 min
Jul 17, 10:47 PM EDTSpecial Marine WarningPHI118 min
Jul 17, 11:07 PM EDTSpecial Weather StatementPHIMiddlesex38 min
Jul 17, 11:08 PM EDTAreal Flood WarningPHIHunterdon12 hr
Jul 17, 11:11 PM EDTSpecial Weather StatementPHIMonmouth, Ocean34 min
Jul 17, 11:20 PM EDTSpecial Marine WarningPHI115 min
Jul 17, 11:26 PM EDTAreal Flood WarningPHISomerset10 hr
Jul 18, 2:41 AM EDTAreal Flood WarningPHIMercer4 hr
Jul 18, 3:48 AM EDTRiver Flood WarningPHIMercer3 hr
Jul 18, 9:08 AM EDTAreal Flood WarningPHISomerset2 hr
Jul 18, 11:03 AM EDTRiver Flood WarningPHIMiddlesex, Somerset88 min
Jul 17, 8:44 PM EDTAreal Flood AdvisoryPHIChester, Montgomery82 min
Jul 17, 8:57 PM EDTSevere Thunderstorm WarningPHIChester48 min
Jul 17, 9:15 PM EDTAreal Flood AdvisoryPHIDelaware, Montgomery, Philadelphia2 hr
Jul 17, 8:40 PM EDTSpecial Weather StatementPHIKent35 min
Jul 17, 10:36 PM EDTSpecial Weather StatementPHIKent24 min
Jul 17, 10:54 PM EDTAreal Flood AdvisoryPHIKent48 min
Jul 17, 10:55 PM EDTSevere Thunderstorm WarningPHIKent50 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.