Alert archive / Delaware / Special Weather Statements in 2011

Special Weather Statement, NWS Philadelphia/Mount Holly

September 23, 2011New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this special weather statement at Sep 23, 2011, 7:21 PM EDT for New Castle County, Delaware. It was in force for 24 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 23, 2011, 7:21 PM EDT (23:21 UTC)
Expired
Sep 23, 2011, 7:45 PM EDT
In force
24 min
Issued by
NWS Philadelphia/Mount Holly

County New Castle County, DE

The radar

The Dover AFB radar (KDOX), 77 km from the middle of the area, began a volume at 23:24 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.4 hours before the alert went out and 163 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, Washington/Dulle, VA at 12:00Z on 2011-09-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 709 joules per kilogram.LCLEL10008507005003002001001 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, Washington/Dulle, VA at 12:00Z on 2011-09-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 54 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
709 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
443 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
54 m²/s²
0-3 km storm-relative helicity
38 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.0

Open this sounding in Storm Lab

The text

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

622 
WWUS81 KPHI 232321
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
721 PM EDT FRI SEP 23 2011

DEZ001-MDZ008-NJZ016-232345-
CECIL MD-NEW CASTLE DE-SALEM NJ-
721 PM EDT FRI SEP 23 2011

...STRONG THUNDERSTORMS WILL AFFECT CECIL...NEW CASTLE AND SALEM
COUNTIES...

AT 719 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 2 MILES SOUTHEAST OF
ELKTON TO 5 MILES NORTHWEST OF MIDDLETOWN TO 9 MILES SOUTHWEST OF
MIDDLETOWN...MOVING EAST AT 25 MPH. THE THUNDERSTORMS WILL BE NEAR
BEAR...GLASGOW AROUND 730 PM...DELAWARE CITY AND ODESSA AROUND 745
PM.

WIND GUSTS TO 50 MPH ARE POSSIBLE WITH THESE STORMS.

THIS THUNDERSTORM IS SHOWING SOME WEAK ROTATION, IF IT BECOMES
STRONGER...IT MIGHT BECOME NECESSARY TO ISSUE A TORNADO WARNING.
IF YOU SEE THREATENING WEATHER, PLEASE SEEK SHELTER IMMEDIATELY.


LAT...LON 3947 7588 3965 7587 3977 7541 3959 7543
      3945 7553 3950 7557 3952 7554 3957 7553
      3958 7556 3946 7558 3943 7554 3941 7556
      3937 7577 3938 7577 3938 7594

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 23, 10:13 AM EDTAreal Flood AdvisoryPHIGloucester, Salem5 hr
Sep 23, 10:52 AM EDTAreal Flood AdvisoryPHIBurlington, Camden, Hunterdon, Mercer, Middlesex, Monmouth and 5 more5 hr
Sep 23, 5:27 PM EDTAreal Flood WarningPHIAtlantic, Camden, Cape May, Cumberland, Gloucester, Salem12 hr
Sep 23, 5:53 PM EDTAreal Flood WarningPHIWarren12 hr
Sep 23, 6:31 PM EDTSpecial Weather StatementPHISalem29 min
Sep 23, 6:34 PM EDTAreal Flood WarningPHIHunterdon, Mercer4 hr
Sep 23, 6:38 PM EDTAreal Flood WarningPHISussex6 hr
Sep 23, 7:30 PM EDTAreal Flood WarningPHIBurlington, Monmouth, Ocean2 hr
Sep 23, 7:48 PM EDTAreal Flood WarningPHIMiddlesex, Morris, Somerset5 hr
Sep 23, 11:49 AM EDTAreal Flood AdvisoryPHIBerks, Carbon, Lehigh, Monroe, Northampton6 hr
Sep 23, 12:47 PM EDTFlash Flood WarningPHIPhiladelphia2 hr
Sep 23, 1:59 PM EDTAreal Flood WarningPHICarbon3 hr
Sep 23, 9:17 AM EDTAreal Flood AdvisoryPHICaroline, Cecil, Kent, Queen Anne's, Talbot6 hr
Sep 23, 4:33 PM EDTAreal Flood WarningPHICaroline, Cecil, Kent, Queen Anne's, Talbot5 hr
Sep 23, 6:21 PM EDTSpecial Weather StatementPHIKent24 min

Nearby

Special Weather Statements in Delaware, 2011Every special weather statement in 2011

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.