Alert archive / Delaware / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 39, NWS Philadelphia/Mount Holly

May 29, 2009Caroline County, Maryland; Kent County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 29, 2009, 5:32 PM EDT for Caroline County, Maryland; Kent County, Sussex County, Delaware. It was in force for 58 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
May 29, 2009, 5:32 PM EDT (21:32 UTC)
Expired
May 29, 2009, 6:30 PM EDT
In force
58 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Kent County, DE, Sussex County, DE, Caroline County, MD

The radar

The Dover AFB radar (KDOX), 2 km from the middle of the area, began a volume at 21:33 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

TimeReportWhereRemark
May 29, 5:40 PM EDTHAIL 1Nne Milford Mill, DEIN ADDITION TO LARGE HAIL, SMALL TREE BRANCHES BLOWN DOWN.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 29, 1:26 PM EDTSevere Thunderstorm WatchSPC8 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 9.5 hours before the alert went out and 93 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 2009-05-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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 2009-05-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 58 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
4 J/kg
Mixed-layer CIN
-283 J/kg
Mixed-layer LCL
620 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
58 m²/s²
0-3 km storm-relative helicity
139 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 292132
SVRPHI
DEC001-005-MDC011-292230-
/O.NEW.KPHI.SV.W.0039.090529T2132Z-090529T2230Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
532 PM EDT FRI MAY 29 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN KENT COUNTY IN CENTRAL DELAWARE...
  SOUTHEASTERN CAROLINE COUNTY IN EASTERN MARYLAND...
  SUSSEX COUNTY IN SOUTHERN DELAWARE...
  THIS INCLUDES THE CITY OF GEORGETOWN...

* UNTIL 630 PM EDT

* AT 529 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING PENNY SIZE
  HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE
  LOCATED ALONG A LINE EXTENDING FROM BOWERS TO GEORGETOWN TO 11
  MILES SOUTHWEST OF FEDERALSBURG...OR ALONG A LINE EXTENDING FROM 9
  MILES SOUTHEAST OF DOVER TO GEORGETOWN TO 16 MILES SOUTHEAST OF
  EASTON...AND MOVING EAST AT 25 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO BIG
  STONE BEACH...SLAUGHTER BEACH...MILTON...LEWES...SYCAMORE...
  LAUREL...REHOBOTH BEACH...GUMBORO...SELBYVILLE...MILLSBORO...
  FENWICK ISLAND AND BETHANY BEACH

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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM EDT FRIDAY
EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN NEW
JERSEY AND SOUTHEAST PENNSYLVANIA.

&&

LAT...LON 3846 7570 3865 7572 3869 7583 3869 7587
      3876 7577 3927 7543 3926 7539 3924 7538
      3909 7540 3898 7529 3893 7530 3880 7516
      3880 7507 3847 7503 3844 7505
TIME...MOT...LOC 2132Z 270DEG 20KT 3906 7538 3870 7543
          3858 7589

$$

MPD
1 follow-up statement
000 
WWUS51 KPHI 292200
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
600 PM EDT FRI MAY 29 2009

DEC001-MDC011-292210-
/O.CAN.KPHI.SV.W.0039.000000T0000Z-090529T2230Z/
KENT DE-CAROLINE MD-
600 PM EDT FRI MAY 29 2009

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN CAROLINE AND
EASTERN KENT COUNTIES IS CANCELLED...

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM EDT FRIDAY
EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN NEW
JERSEY AND SOUTHEAST PENNSYLVANIA.

LAT...LON 3846 7570 3875 7570 3877 7562 3882 7554
      3888 7551 3891 7547 3892 7541 3895 7539
      3894 7530 3893 7530 3880 7516 3880 7507
      3847 7503 3844 7505
TIME...MOT...LOC 2200Z 270DEG 20KT 3906 7518 3870 7523
          3858 7569

$$

DEC005-292230-
/O.CON.KPHI.SV.W.0039.000000T0000Z-090529T2230Z/
SUSSEX DE-
600 PM EDT FRI MAY 29 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM EDT
FOR SUSSEX COUNTY...

AT 558 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING PENNY
SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS
WERE LOCATED ALONG A LINE EXTENDING FROM 12 MILES NORTHEAST OF
SLAUGHTER BEACH TO 7 MILES SOUTHEAST OF MILTON TO BETHEL...OR ALONG A
LINE EXTENDING FROM 18 MILES NORTHWEST OF CAPE MAY TO 8 MILES EAST OF
GEORGETOWN TO 16 MILES NORTHWEST OF SALISBURY...MOVING EAST AT 25
MPH.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
LEWES...LAUREL...HENLOPEN ACRES...SYCAMORE...REHOBOTH BEACH...DEWEY
BEACH...GUMBORO...SOUTH BETHANY...SELBYVILLE...OCEAN VIEW...
MILLVILLE...MILLSBORO...LONG NECK...FRANKFORD...FENWICK ISLAND...
DAGSBORO AND BETHANY BEACH

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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM EDT FRIDAY
EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN NEW
JERSEY AND SOUTHEAST PENNSYLVANIA.

&&

LAT...LON 3846 7570 3875 7570 3877 7562 3882 7554
      3888 7551 3891 7547 3892 7541 3895 7539
      3894 7530 3893 7530 3880 7516 3880 7507
      3847 7503 3844 7505
TIME...MOT...LOC 2200Z 270DEG 20KT 3906 7518 3870 7523
          3858 7569

$$

MPD

The office that day

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

IssuedProductOfficeCountiesLasted
May 29, 3:22 PM EDTSevere Thunderstorm WarningPHICaroline, Kent, Queen Anne's, Talbot68 min
May 29, 4:45 PM EDTSevere Thunderstorm WarningPHICaroline, Queen Anne's, Talbot50 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2009Severe Thunderstorm Warnings in Maryland, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.