Alert archive / West Virginia / Flash Flood Warnings in 2012

Flash Flood Warning 41, NWS Blacksburg, VA

August 1, 2012Mercer County, West Virginia

NWS Blacksburg, VA issued this flash flood warning at Aug 1, 2012, 10:02 PM EDT for Mercer County, West Virginia. It was in force for 94 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
Aug 1, 2012, 10:02 PM EDT (02:02 UTC)
Expired
Aug 1, 2012, 11:36 PM EDT
In force
94 min
Issued by
NWS Blacksburg, VA
Area
Storm-based polygon
Flood severity
None

County Mercer County, WV

The radar

The Roanoke radar (KFCX), 96 km from the middle of the area, began a volume at 02:05 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
Aug 1, 10:15 PM EDTFLASH FLOODMatoaka, WVROCKSLIDE CAUSED A BRIEF ROAD CLOSURE IN MOTOAKA. ROAD NAME UNKNOWN AT THIS POINT.

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

The nearest sounding before it

Roanoke, VA (KRNK), launched 00:00Z, 2.0 hours before the alert went out and 155 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, Roanoke, VA at 00:00Z on 2012-08-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1079 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, Roanoke, VA at 00:00Z on 2012-08-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 75 square meters per square second.193958Sfc1 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
1079 J/kg
Mixed-layer CIN
-25 J/kg
Mixed-layer LCL
1361 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
75 m²/s²
0-3 km storm-relative helicity
114 m²/s²
Significant tornado parameter
0.2
Supercell composite
2.9

Open this sounding in Storm Lab

The text

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

476 
WGUS51 KRNK 020202
FFWRNK
WVC055-020800-
/O.NEW.KRNK.FF.W.0041.120802T0202Z-120802T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BLACKSBURG VA
1002 PM EDT WED AUG 1 2012

THE NATIONAL WEATHER SERVICE IN BLACKSBURG HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WEST CENTRAL MERCER COUNTY IN SOUTHEAST WEST VIRGINIA

* UNTIL 400 AM EDT.

* AT 957 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM NEAR WENONAH...OR NEAR
  MATOAKA...MOVING SOUTHEAST AT 5 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  MONTCALM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

RADAR INDICATES THAT RAINFALL OF 2.5 TO 3.0 INCHES HAS FALLEN NEAR 
MATOAKA...WITH ADDITIONAL RAINFALL AMOUNTS OF 1.0 TO 1.5 INCHES 
EXPECTED DURING THE NEXT HOUR AS THUNDERSTORMS PERSIST ACROSS THIS 
AREA. THE GROUND IN THIS AREA IS SATURATED FROM PREVIOUS HEAVY 
RAINFALL AND THUNDERSTORMS.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

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.

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.

IN MOUNTAINOUS AND HILLY TERRAIN THERE ARE HUNDREDS OF LOW WATER 
CROSSINGS WHICH ARE POTENTIALLY DANGEROUS IN HEAVY RAIN. DO NOT 
ATTEMPT TO TRAVEL ACROSS FLOODED ROADS. FIND ALTERNATE ROUTES. IT 
TAKES ONLY A FEW INCHES OF SWIFTLY FLOWING WATER TO CARRY VEHICLES 
AWAY.

PLEASE RELAY ANY REPORTS OF FLOODING INCLUDING MUDSLIDES...OR ROAD
CLOSURES TO THE NATIONAL WEATHER SERVICE IN BLACKSBURG BY CALLING
TOLL FREE...1...8 6 6...2 1 5...4 3 2 4. DELAYED REPORTS ARE WELCOME.

&&

LAT...LON 3751 8124 3742 8113 3737 8118 3735 8125
      3746 8129

$$

RAB
2 follow-up statements
791 
WGUS71 KRNK 020306
FFSRNK

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
1106 PM EDT WED AUG 1 2012

WVC055-020800-
/O.CON.KRNK.FF.W.0041.000000T0000Z-120802T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MERCER WV-
1106 PM EDT WED AUG 1 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 AM EDT FOR
WESTERN MERCER COUNTY...

AT 1101 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THAT THE THUNDERSTORM THAT PROMPTED THE FLASH FLOOD WARNING FOR 
WESTERN MERCER COUNTY HAS DISSIPATED. CONSIDERABLE RUNOFF WILL 
CONTINUE ACROSS THIS AREA DURING THE NEXT HOUR OR SO AS RAINFALL OF 
2 TO 3 INCHES FELL WITHIN THIS AREA DURING THE PAST COUPLE OF HOURS. 
IF THE AREA REMAINS RAIN FREE...THE FLASH FLOOD WARNING WILL LIKELY 
BE CANCELLED WELL BEFORE 4 AM EDT THURSDAY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PLEASE RELAY ANY REPORTS OF FLOODING INCLUDING MUDSLIDES...OR ROAD
CLOSURES TO THE NATIONAL WEATHER SERVICE IN BLACKSBURG BY CALLING
TOLL FREE...1...8 6 6...2 1 5...4 3 2 4. DELAYED REPORTS ARE WELCOME.

&&

LAT...LON 3751 8124 3742 8113 3737 8118 3735 8125
      3746 8129

$$

RAB
037 
WGUS71 KRNK 020336
FFSRNK

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
1136 PM EDT WED AUG 1 2012

WVC055-020346-
/O.CAN.KRNK.FF.W.0041.000000T0000Z-120802T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MERCER WV-
1136 PM EDT WED AUG 1 2012

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR WESTERN MERCER
COUNTY...

ANY FLOODING HAS ENDED OVER THE WARNED AREA...THUS THE FLASH FLOOD 
WARNING HAS BEEN CANCELLED.

LAT...LON 3751 8124 3742 8113 3737 8118 3735 8125
      3746 8129

$$

JH

The office that day

Everything else NWS Blacksburg, VA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 1, 8:44 PM EDTSpecial Weather StatementRNKMercer61 min
Aug 1, 9:16 PM EDTSpecial Weather StatementRNKGreenbrier44 min

Nearby

Flash Flood Warnings in West Virginia, 2012Every flash flood warning in 2012

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.