Alert archive / Maryland / Flash Flood Warnings in 2009

Flash Flood Warning 51, NWS Philadelphia/Mount Holly

August 22, 2009Caroline County, Maryland

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 22, 2009, 4:46 PM EDT for Caroline County, 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
Aug 22, 2009, 4:46 PM EDT (20:46 UTC)
Expired
Aug 22, 2009, 10:14 PM EDT
In force
5 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

County Caroline County, MD

The radar

The Dover AFB radar (KDOX), 36 km from the middle of the area, began a volume at 20:46 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, 8.8 hours before the alert went out and 113 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 2009-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1451 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 2009-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 square meters per square second.1939Sfc1 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
1451 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
643 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
40 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 
WGUS51 KPHI 222046
FFWPHI
MDC011-230045-
/O.NEW.KPHI.FF.W.0051.090822T2046Z-090823T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
446 PM EDT SAT AUG 22 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL CAROLINE COUNTY IN EASTERN MARYLAND...

* UNTIL 845 PM EDT

* AT 443 PM EDT...MORE HEAVY RAIN IS GOING TO ADD TO THE FLASH FLOODING
  PROBLEM THAT OCCURED EARLIER THIS MORNING.  THIS IS BECOMING A 
  POTENTIALLY DANGEROUS SITUATION ESPECIALLY IN THE TOWN OF RIDGELY WHERE
  OVER NINE INCHES FELL THIS MORNING. 

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO RIDGELY AND
  DENTON

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

&&

LAT...LON 3893 7592 3900 7583 3883 7572 3871 7586

$$

EBERWINE
3 follow-up statements
000 
WGUS71 KPHI 222231
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
631 PM EDT SAT AUG 22 2009

MDC011-230045-
/O.CON.KPHI.FF.W.0051.000000T0000Z-090823T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CAROLINE MD-
631 PM EDT SAT AUG 22 2009

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 PM EDT FOR
CENTRAL CAROLINE COUNTY...

POTENTIALLY DANGEROUS SITUATION DEVELOPING THROUGHOUT THE EVENING
HOURS ESPECIALLY OVER PARTS OF THE COUNTY THAT RECEIVED VERY HEAVY
RAINS THIS MORNING.

A ROAD WAS WASHED OUT SOUTH OF RIDGELY THIS MORNING AND ANY ATTEMPT
AT CLEANING UP WILL BE HAMPERED BY ADDITIONAL RAINS THIS EVENING. 

IT IS VERY POSSIBLE THAT PARTS OF CAROLINE COUNTY COULD RECEIVE ANOTHER
THREE TO FIVE INCHES BEFORE MIDNIGHT.     

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

&&

LAT...LON 3893 7592 3900 7583 3883 7572 3871 7586

$$

EBERWINE
000 
WGUS51 KPHI 230034
FFWPHI
MDC011-230245-
/O.EXT.KPHI.FF.W.0051.000000T0000Z-090823T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
834 PM EDT SAT AUG 22 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS EXTENDED THE

* FLASH FLOOD WARNING FOR...
  CENTRAL CAROLINE COUNTY IN EASTERN MARYLAND...

* UNTIL 1045 PM EDT

* AT 826 PM EDT...VERY HEAVY RAIN WAS STILL FALLING IN THE VICINITY
  OF RIDGELY. RADAR ESTIMATED ABOUT AN INCH AN HOUR.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO RIDGELY AND
  DENTON

RIDGELY HAS RECEIVED OVER 13 INCHES IN THE PAST 24 HOURS INCLUDING
THE 5 OR 6 INCHES THIS EVENING. BASEMENTS AND CRAWL SPACES ARE FLOODED
WITH SOME ROADS WASHED AWAY AND UP TO SEVEN ROADS CLOSED. THE RAIN WILL
CONTINUE HEAVY FOR THE NEXT HOUR THEN BEGIN TO TAPER OFF.

PLEASE AVOID THIS PART OF CARLINE COUNTY TONIGHT.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

&&

LAT...LON 3893 7592 3900 7583 3883 7572 3871 7586

$$

EBERWINE
000 
WGUS71 KPHI 230214
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1014 PM EDT SAT AUG 22 2009

MDC011-230222-
/O.CAN.KPHI.FF.W.0051.000000T0000Z-090823T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CAROLINE MD-
1014 PM EDT SAT AUG 22 2009

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR CENTRAL CAROLINE
COUNTY...

THE RAIN HAS ENDED OVER CAROLINE COUNTY BUT TRAVEL THROUGH THE COUNTY
ESPECIALLY THROUGH RIDGELY SHOULD BE AVOIDED SINCE SEVERAL ROADS ARE
STILL FLOODED AND SOME WERE WASHED AWAY. CHECK WITH OFFICIALS FOR THE
LATEST INFORMATION ON TRAVEL.

THERE IS AN AREA OF RAIN OVER QUEEN ANNES COUNTY AND NORTH TO PENNSYLVANIA
BUT IT IS NOT EXPECTED TO WIDESPREAD OR VERY HEAVY. HOWEVER...A FLASH
FLOOD WATCH CONTINUES FOR THE REGION.

LAT...LON 3893 7592 3900 7583 3883 7572 3871 7586

$$

EBERWINE

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 21, 10:14 PM EDTAreal Flood AdvisoryPHICecil, Kent3 hr
Aug 21, 11:49 PM EDTAreal Flood AdvisoryPHICaroline, Queen Anne's, Talbot116 min
Aug 22, 12:45 AM EDTAreal Flood WarningPHICaroline17 hr
Aug 22, 1:28 AM EDTFlash Flood WarningPHICaroline, Queen Anne's4 hr
Aug 22, 2:19 AM EDTAreal Flood AdvisoryPHICaroline, Queen Anne's, Talbot6 hr
Aug 22, 4:26 AM EDTAreal Flood AdvisoryPHICaroline6 hr
Aug 22, 5:42 AM EDTAreal Flood AdvisoryPHICaroline, Queen Anne's3 hr
Aug 22, 8:12 AM EDTAreal Flood AdvisoryPHICaroline, Kent, Queen Anne's, Talbot3 hr
Aug 22, 3:53 PM EDTFlash Flood WarningPHICaroline, Talbot6 hr
Aug 22, 5:40 PM EDTAreal Flood WarningPHICaroline14 hr
Aug 22, 6:02 PM EDTFlash Flood WarningPHICecil, Kent, Queen Anne's4 hr

Nearby

Flash Flood Warnings in Maryland, 2009Every flash flood 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.