Alert archive / Delaware / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 19, NWS Philadelphia/Mount Holly

May 7, 2009Kent County, New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 7, 2009, 1:33 PM EDT for Kent County, New Castle County, Delaware. It was in force for 66 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
May 7, 2009, 1:33 PM EDT (17:33 UTC)
Expired
May 7, 2009, 2:39 PM EDT
In force
66 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Kent County, DE, New Castle County, DE

The radar

The Dover AFB radar (KDOX), 63 km from the middle of the area, began a volume at 17:35 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 5.6 hours before the alert went out and 46 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, Phillips Aaf/Abe, MD at 12:00Z on 2009-05-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 38 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Phillips Aaf/Abe, MD at 12:00Z on 2009-05-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 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
38 J/kg
Mixed-layer CIN
-66 J/kg
Mixed-layer LCL
642 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
106 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WUUS51 KPHI 071733
SVRPHI
DEC001-003-071900-
/O.NEW.KPHI.SV.W.0019.090507T1733Z-090507T1900Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
133 PM EDT THU MAY 7 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN KENT COUNTY IN CENTRAL DELAWARE...
  SOUTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  THIS INCLUDES THE CITY OF MIDDLETOWN...

* UNTIL 300 PM EDT

* AT 132 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 8 MILES
  NORTHWEST OF DELANEY CORNER...OR 9 MILES SOUTHWEST OF MIDDLETOWN...
  AND MOVING NORTHEAST AT 35 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  9 MILES NORTHWEST OF GREEN SPRING BY 145 PM EDT...
  MIDDLETOWN AND MOUNT PLEASANT BY 150 PM EDT...
  SAINT GEORGES BY 200 PM EDT...
  PORT PENN AND DELAWARE CITY BY 205 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

&&

LAT...LON 3912 7575 3950 7578 3960 7560 3959 7559
      3961 7557 3960 7555 3954 7555 3946 7558
      3942 7552 3935 7548 3932 7543 3924 7538
      3922 7539 3909 7574
TIME...MOT...LOC 1733Z 241DEG 31KT 3938 7586

$$

 
TFG
2 follow-up statements
000 
WWUS51 KPHI 071824
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
224 PM EDT THU MAY 7 2009

DEC001-003-071900-
/O.CON.KPHI.SV.W.0019.000000T0000Z-090507T1900Z/
KENT DE-NEW CASTLE DE-
224 PM EDT THU MAY 7 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM EDT
FOR SOUTH CENTRAL NEW CASTLE AND NORTHERN KENT COUNTIES...

AT 222 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM LIKELY OF PRODUCING PENNY SIZE
HAIL...AND DAMAGING WINDS UP TO 60 MPH.  THIS STORM WAS
LOCATED NEAR SMYRNA...OR 12 MILES SOUTHEAST OF MIDDLETOWN...MOVING
NORTHEAST AT 30 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  WOODLAND BEACH BY 235 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

&&

LAT...LON 3916 7568 3934 7571 3943 7553 3942 7552
      3935 7548 3932 7543 3926 7539
TIME...MOT...LOC 1824Z 245DEG 27KT 3933 7557

$$
 
TFG
000 
WWUS51 KPHI 071839
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
239 PM EDT THU MAY 7 2009

DEC001-003-071849-
/O.CAN.KPHI.SV.W.0019.000000T0000Z-090507T1900Z/
KENT DE-NEW CASTLE DE-
239 PM EDT THU MAY 7 2009

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL NEW CASTLE AND
NORTHERN KENT COUNTIES IS CANCELLED...

THE SEVERE STORM HAS CROSSED THE DELAWARE RIVER INTO NEW JERSEY.

LAT...LON 3916 7568 3934 7571 3943 7553 3942 7552
      3935 7548 3932 7543 3926 7539
TIME...MOT...LOC 1839Z 245DEG 27KT 3938 7543

$$
 
TFG

The office that day

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

IssuedProductOfficeCountiesLasted
May 6, 9:01 PM EDTFlood WatchPHINew Castle19 hr
May 7, 1:51 AM EDTFlash Flood WarningPHINew Castle5 hr
May 7, 2:00 AM EDTRiver Flood WarningPHINew Castle3 hr
May 7, 1:22 PM EDTAreal Flood AdvisoryPHINew Castle4 hr

Nearby

Severe Thunderstorm Warnings in Delaware, 2009Every severe thunderstorm warning in 2009

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.