Alert archive / New Jersey / Special Marine Warnings in 2021

Special Marine Warning 134, NWS Philadelphia/Mount Holly

September 9, 2021

NWS Philadelphia/Mount Holly issued this special marine warning at Sep 9, 2021, 12:18 AM EDT. It was in force for 57 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
Sep 9, 2021, 12:18 AM EDT (04:18 UTC)
Expired
Sep 9, 2021, 1:15 AM EDT
In force
57 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), 79 km from the middle of the area, began a volume at 04:19 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, 4.3 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-pSkew-T log-p diagram, Wallops Is Stn, VA at 00:00Z on 2021-09-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 933 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 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 2021-09-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 97 square meters per square second.19395878Sfc1 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
933 J/kg
Mixed-layer CIN
-109 J/kg
Mixed-layer LCL
915 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
97 m²/s²
0-3 km storm-relative helicity
169 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

807 
WHUS51 KPHI 090418
SMWPHI
ANZ430-090515-
/O.NEW.KPHI.MA.W.0134.210909T0418Z-210909T0515Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Mount Holly NJ
1218 AM EDT Thu Sep 9 2021

The National Weather Service in Mount Holly NJ has issued a

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

* Until 115 AM EDT.

* At 1218 AM EDT, strong thunderstorms were located along a line
  extending from 23 nm northeast of Reedy Point to 9 nm northwest of
  Pea Patch Island, moving southeast at 20 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...
  Woodland Beach, Stony Point, Sea Breeze, Ship John Shoal Light, Pea
  Patch Island and Reedy Point.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor until hazardous weather passes.

&&

LAT...LON 3968 7562 3971 7558 3975 7557 3977 7552
      3974 7545 3969 7544 3961 7535 3951 7539
      3948 7533 3943 7534 3943 7529 3946 7525
      3946 7520 3939 7517 3937 7517 3918 7547
      3923 7561
TIME...MOT...LOC 0418Z 294DEG 22KT 3991 7531 3967 7575 

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

$$

SFJ
2 follow-up statements
690 
FZUS71 KPHI 090432
MWSPHI

Marine Weather Statement
National Weather Service Mount Holly NJ
1232 AM EDT Thu Sep 9 2021

ANZ430-090515-
/O.CON.KPHI.MA.W.0134.000000T0000Z-210909T0515Z/
1232 AM EDT Thu Sep 9 2021

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 115 AM EDT...

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

At 1232 AM EDT, showers were located along a line extending from 24
nm northeast of Reedy Point to near Pea Patch Island, moving
southeast 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...
Woodland Beach, Stony Point, Sea Breeze, Ship John Shoal Light, Pea
Patch Island and Reedy Point.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3968 7562 3971 7558 3975 7557 3977 7552
      3974 7545 3969 7544 3961 7535 3951 7539
      3948 7533 3943 7534 3943 7529 3946 7525
      3946 7520 3939 7517 3937 7517 3918 7547
      3923 7561
TIME...MOT...LOC 0432Z 294DEG 22KT 3988 7522 3964 7566 

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

$$

SFJ
920 
FZUS71 KPHI 090513
MWSPHI

Marine Weather Statement
National Weather Service Mount Holly NJ
113 AM EDT Thu Sep 9 2021

ANZ430-090523-
/O.EXP.KPHI.MA.W.0134.000000T0000Z-210909T0515Z/
113 AM EDT Thu Sep 9 2021

...THE SPECIAL MARINE WARNING WILL EXPIRE AT 115 AM EDT...

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

The showers have weakened and no longer pose a significant threat to
boaters.

LAT...LON 3968 7562 3971 7558 3975 7557 3977 7552
      3974 7545 3969 7544 3961 7535 3951 7539
      3948 7533 3943 7534 3943 7529 3946 7525
      3946 7520 3939 7517 3937 7517 3918 7547
      3923 7561
TIME...MOT...LOC 0513Z 294DEG 22KT 3978 7493 3954 7537 

$$

SFJ

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 8, 9:16 PM EDTAreal Flood AdvisoryPHIWarren3 hr
Sep 8, 9:16 PM EDTSpecial Weather StatementPHISussex, Warren29 min
Sep 8, 9:43 PM EDTSpecial Weather StatementPHISussex, Warren47 min
Sep 8, 10:42 PM EDTFlash Flood WarningPHIWarren6 hr
Sep 8, 10:56 PM EDTSpecial Weather StatementPHIWarren34 min
Sep 8, 11:27 PM EDTSevere Thunderstorm WarningPHIHunterdon, Warren48 min
Sep 8, 11:30 PM EDTAreal Flood AdvisoryPHIMorris, Sussex4 hr
Sep 9, 12:07 AM EDTSpecial Weather StatementPHIHunterdon, Somerset, Warren23 min
Sep 9, 12:30 AM EDTSpecial Weather StatementPHIMorris30 min
Sep 9, 12:41 AM EDTSpecial Marine WarningPHI52 min
Sep 9, 2:17 AM EDTSpecial Weather StatementPHIOcean28 min
Sep 9, 2:46 AM EDTSpecial Weather StatementPHIAtlantic29 min
Sep 9, 3:14 AM EDTSpecial Weather StatementPHIAtlantic31 min
Sep 9, 3:30 AM EDTAreal Flood AdvisoryPHIAtlantic, Burlington, Cape May, Cumberland112 min
Sep 9, 4:28 AM EDTAreal Flood WarningPHIWarren4 hr
Sep 8, 8:47 PM EDTSpecial Weather StatementPHINorthampton28 min
Sep 8, 9:12 PM EDTSpecial Weather StatementPHILehigh48 min
Sep 8, 9:38 PM EDTSpecial Weather StatementPHIBerks52 min
Sep 8, 9:46 PM EDTSpecial Weather StatementPHILehigh, Northampton44 min
Sep 8, 9:48 PM EDTFlash Flood WarningPHILehigh, Northampton7 hr
Sep 8, 9:59 PM EDTAreal Flood AdvisoryPHIBerks3 hr
Sep 8, 10:11 PM EDTSevere Thunderstorm WarningPHIBerks49 min
Sep 8, 10:23 PM EDTTornado WarningPHIBerks22 min
Sep 8, 10:27 PM EDTSpecial Weather StatementPHINorthampton33 min
Sep 8, 10:47 PM EDTAreal Flood AdvisoryPHICarbon, Monroe3 hr
Sep 8, 10:47 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh, Montgomery, Northampton58 min
Sep 8, 11:35 PM EDTSpecial Weather StatementPHIChester, Delaware, Montgomery40 min
Sep 9, 12:08 AM EDTSpecial Weather StatementPHIBucks, Delaware, Montgomery, Philadelphia37 min
Sep 9, 4:26 AM EDTAreal Flood WarningPHILehigh, Northampton3 hr
Sep 9, 12:58 AM EDTSpecial Weather StatementPHINew Castle32 min
Sep 9, 1:12 AM EDTAreal Flood AdvisoryPHINew Castle62 min
Sep 9, 5:37 AM EDTAreal Flood AdvisoryPHIKent, New Castle, Sussex3 hr

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.