Alert archive / Maryland / Areal Flood Warnings in 2011

Areal Flood Warning 87, NWS Philadelphia/Mount Holly

September 23, 2011Kent County, New Castle County, Sussex County, Delaware; 5 counties in Maryland

NWS Philadelphia/Mount Holly issued this areal flood warning at Sep 23, 2011, 4:33 PM EDT for Kent County, New Castle County, Sussex County, Delaware; 5 counties in Maryland. It was in force for 5 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
Sep 23, 2011, 4:33 PM EDT (20:33 UTC)
Expired
Sep 23, 2011, 9:45 PM EDT
In force
5 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, Cecil County, MD, Kent County, MD, Queen Anne's County, MD, Talbot County, MD

The radar

The Dover AFB radar (KDOX), 48 km from the middle of the area, began a volume at 20:36 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 12:00Z, 8.6 hours before the alert went out and 124 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 12:00Z on 2011-09-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 57 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 12:00Z on 2011-09-23The 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
57 J/kg
Mixed-layer CIN
-101 J/kg
Mixed-layer LCL
903 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
58 m²/s²
0-3 km storm-relative helicity
92 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.

562 
WGUS41 KPHI 232033
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
433 PM EDT FRI SEP 23 2011

DEC001-003-005-MDC011-015-029-035-041-240230-
/O.NEW.KPHI.FA.W.0087.110923T2033Z-110924T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
KENT DE-CAROLINE MD-CECIL MD-KENT MD-QUEEN ANNE'S MD-TALBOT MD-
SUSSEX DE-NEW CASTLE DE-
433 PM EDT FRI SEP 23 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN...
  KENT COUNTY IN CENTRAL DELAWARE...
  CAROLINE COUNTY IN EASTERN MARYLAND...
  CECIL COUNTY IN NORTHEAST MARYLAND...
  QUEEN ANNE'S COUNTY IN NORTHEAST MARYLAND...
  TALBOT COUNTY IN EASTERN MARYLAND...
  SUSSEX COUNTY IN SOUTHERN DELAWARE...
  NEW CASTLE COUNTY IN NORTHERN DELAWARE...

* UNTIL 1030 PM EDT

* AT 425 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR SHOWED MORE 
RAIN MOVING BACK INTO THE WARNED AREA. WITH UP TO TWO INCHES OF RAIN 
ALREADY FALLING ACROSS PORTIONS OF THE DELMARVA COMBINED WITH 
ANOTHER ONE TO TWO INCHES THIS EVENING, EXCESSIVE RUNOFF WILL CAUSE 
FLOODING OF SMALL CREEKS AND STREAMS, URBAN AREAS, HIGHWAYS, STREETS 
AND UNDERPASSES AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING 
SPOTS.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF 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.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

&&

LAT...LON 3846 7570 3869 7583 3856 7604 3867 7636
      3887 7625 3882 7621 3883 7620 3894 7624
      3884 7637 3886 7639 3905 7631 3900 7618
      3918 7628 3951 7599 3972 7623 3980 7542
      3946 7558 3880 7507 3845 7505

$$

KRUZDLO
2 follow-up statements
005 
WGUS81 KPHI 240012
FLSPHI

FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
812 PM EDT FRI SEP 23 2011

DEC001-005-MDC011-240016-
/O.CAN.KPHI.FA.W.0087.000000T0000Z-110924T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
KENT DE-CAROLINE MD-SUSSEX DE-
812 PM EDT FRI SEP 23 2011

...THE FLOOD WARNING HAS BEEN CANCELLED FOR URBAN AREAS AND SMALL
STREAMS IN SUSSEX...CAROLINE AND KENT COUNTIES...

THE RAINS HAVE MOVED NORTH AND EAST. THE FLOOD WARNING HAS BEEN 
CANCELLED.


LAT...LON 3868 7634 3887 7625 3882 7621 3882 7620
      3883 7620 3894 7624 3885 7638 3905 7631
      3900 7618 3918 7628 3951 7599 3972 7623
      3980 7542 3962 7560 3937 7552 3929 7576
      3914 7575 3897 7595 3860 7598

$$

DEC003-MDC015-029-035-041-240230-
/O.CON.KPHI.FA.W.0087.000000T0000Z-110924T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CECIL MD-KENT MD-QUEEN ANNE'S MD-TALBOT MD-NEW CASTLE DE-
812 PM EDT FRI SEP 23 2011

...THE FLOOD WARNING REMAINS IN EFFECT UNTIL 1030 PM EDT FOR URBAN
AREAS AND SMALL STREAMS IN NEW CASTLE...TALBOT...QUEEN ANNE'S...KENT
AND CECIL COUNTIES...

AT 806 PM EDT...ALTHOUGH ONLY LIGHT SHOWERS REMAINED ACROSS THE 
WARNED AREA, THE WARNING WILL REMAIN IN EFFECT UNTIL THE HEAVIER 
RAINS FROM THIS EVENING HAVE DRAINED.   

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF 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.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

&&

LAT...LON 3868 7634 3887 7625 3882 7621 3882 7620
      3883 7620 3894 7624 3885 7638 3905 7631
      3900 7618 3918 7628 3951 7599 3972 7623
      3980 7542 3962 7560 3937 7552 3929 7576
      3914 7575 3897 7595 3860 7598

$$

KRUZDLO
208 
WGUS81 KPHI 240145
FLSPHI

FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
945 PM EDT FRI SEP 23 2011

DEC003-MDC015-029-035-041-240153-
/O.CAN.KPHI.FA.W.0087.000000T0000Z-110924T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CECIL MD-KENT MD-QUEEN ANNE'S MD-TALBOT MD-NEW CASTLE DE-
945 PM EDT FRI SEP 23 2011

...THE FLOOD WARNING HAS BEEN CANCELLED FOR URBAN AREAS AND SMALL
STREAMS IN NEW CASTLE...TALBOT...QUEEN ANNE'S...KENT AND CECIL
COUNTIES...

THE RAIN HAS MOVED OUT OF THE AREA. NO NEW FLOODING IS EXPECTED. 
THERE IS A SEPARATE RIVER FLOOD WARNING IN EFFECT FOR THE CHRISTINA 
RIVER IN NORTHERN NEW CASTLE COUNTY. 

LAT...LON 3868 7634 3887 7625 3882 7621 3882 7620
      3883 7620 3894 7624 3885 7638 3905 7631
      3900 7618 3918 7628 3951 7599 3972 7623
      3980 7542 3962 7560 3937 7552 3929 7576
      3914 7575 3897 7595 3860 7598

$$

KRUZDLO

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 23, 10:13 AM EDTAreal Flood AdvisoryPHIKent, New Castle5 hr
Sep 23, 7:21 PM EDTSpecial Weather StatementPHINew Castle24 min
Sep 23, 9:17 AM EDTAreal Flood AdvisoryPHICaroline, Cecil, Kent, Queen Anne's, Talbot6 hr
Sep 23, 6:21 PM EDTSpecial Weather StatementPHIKent24 min

Nearby

Areal Flood Warnings in Maryland, 2011Areal Flood Warnings in Delaware, 2011Every areal 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.