Alert archive / Maryland / Flash Flood Warnings in 2011

Flash Flood Warning 24, NWS Philadelphia/Mount Holly

August 14, 2011Caroline County, Kent County, Queen Anne's County, Maryland; Kent County, New Castle County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 14, 2011, 2:27 AM EDT for Caroline County, Kent County, Queen Anne's County, Maryland; Kent County, New Castle County, Sussex County, Delaware. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 14, 2011, 2:27 AM EDT (06:27 UTC)
Expired
Aug 14, 2011, 6:30 AM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Kent County, DE, New Castle County, DE, Sussex County, DE, Caroline County, MD, Kent County, MD, Queen Anne's County, MD

The radar

The Dover AFB radar (KDOX), 54 km from the middle of the area, began a volume at 06:27 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, 6.5 hours before the alert went out and 152 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 2011-08-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 250 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, Wallops Is Stn, VA at 00:00Z on 2011-08-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -9 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
250 J/kg
Mixed-layer CIN
-40 J/kg
Mixed-layer LCL
978 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
-9 m²/s²
0-3 km storm-relative helicity
13 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.

670 
WGUS51 KPHI 140627
FFWPHI
DEC001-003-005-MDC011-029-035-141030-
/O.NEW.KPHI.FF.W.0024.110814T0627Z-110814T1030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
227 AM EDT SUN AUG 14 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  KENT COUNTY DELAWARE...
  CAROLINE COUNTY MARYLAND...
  NORTHEASTERN KENT COUNTY MARYLAND...
  EASTERN QUEEN ANNE'S COUNTY...
  NORTHWESTERN SUSSEX COUNTY...
  NEW CASTLE COUNTY...

* UNTIL 630 AM EDT...

* AT 222 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  HEAVY RAIN OVER THE WARNED AREA...UP TO TWO INCHES HAS ALREADY     
  FALLEN IN SOME PLACES IN THE LAST TWO HOURS. WITH ADDITIONAL RAIN  
  ON THE WAY...FLASH FLOODING IS EXPECTED WHERE THE HEAVIEST RAIN    
  HAPPENS TO FALL.  


PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE 
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE 
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS 
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

PLEASE REPORT FLOODING...HAIL OR WIND DAMAGE TO THE NATIONAL WEATHER
SERVICE BY CALLING TOLL FREE...1-877-633-6772.

&&

LAT...LON 3873 7601 3881 7590 3892 7598 3937 7588
      3939 7577 3972 7579 3984 7566 3983 7549
      3979 7542 3963 7561 3959 7555 3959 7558
      3954 7556 3948 7559 3934 7546 3919 7539
      3907 7539 3897 7529 3869 7582 3867 7595

$$

JJM

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 14, 12:37 AM EDTAreal Flood AdvisoryPHICecil3 hr
Aug 14, 1:12 AM EDTFlash Flood WarningPHICecil4 hr
Aug 14, 1:51 AM EDTAreal Flood AdvisoryPHICaroline, Kent, Queen Anne's, Talbot6 hr
Aug 14, 3:42 AM EDTFlash Flood WatchPHICaroline, Cecil, Kent, Queen Anne's, Talbot25 hr
Aug 14, 5:03 AM EDTFlash Flood WarningPHICecil, Kent, Queen Anne's4 hr
Aug 14, 7:43 AM EDTFlash Flood WarningPHIKent, Queen Anne's4 hr
Aug 14, 8:41 AM EDTFlash Flood WarningPHICecil, Kent, Queen Anne's4 hr
Aug 14, 12:16 PM EDTAreal Flood WarningPHICecil, Kent4 hr
Aug 14, 6:39 AM EDTRiver Flood WarningPHINew Castle13 hr
Aug 14, 6:45 AM EDTAreal Flood AdvisoryPHIKent, New Castle4 hr
Aug 14, 11:40 AM EDTAreal Flood WarningPHIKent, New Castle18 hr
Aug 14, 11:47 AM EDTSevere Thunderstorm WarningPHIKent28 min
Aug 14, 2:56 PM EDTRiver Flood WarningPHINew Castle3 hr

Nearby

Flash Flood Warnings in Maryland, 2011Flash Flood Warnings in Delaware, 2011Every flash flood warning 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.