Alert archive / Maryland / Flash Flood Warnings in 2000

Flash Flood Warning 22, NWS Baltimore/Washington

July 31, 2000Allegany County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Jul 31, 2000, 4:42 PM EDT for Allegany County, Maryland. It was in force for 78 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued
Jul 31, 2000, 4:42 PM EDT (20:42 UTC)
Expired
Jul 31, 2000, 6:00 PM EDT
In force
78 min
Issued by
NWS Baltimore/Washington
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Allegany County, MD

The radar

The Sterling radar (KLWX), 142 km from the middle of the area, began a volume at 20:42 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

Pittsburgh, PA (KPIT), launched 12:00Z, 8.7 hours before the alert went out and 134 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, Pittsburgh, PA at 12:00Z on 2000-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 618 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Pittsburgh, PA at 12:00Z on 2000-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 123 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
618 J/kg
Mixed-layer CIN
-50 J/kg
Mixed-layer LCL
869 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
123 m²/s²
0-3 km storm-relative helicity
143 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.4

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KLWX 312046
FFWLWX
MDC001-312200-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BALTIMORE-WASHINGTON
442 PM EDT MON JUL 31 2000

THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WESTERN AND CENTRAL ALLEGANY COUNTY IN WESTERN MARYLAND

* UNTIL 600 PM EDT

* AT 436 PM EDT...WEATHER SPOTTERS REPORTED THAT GEORGES CREEK
  IN WESTERNPORT TO BE OUT OF ITS BANKS. DOPPTER RADAR SHOWED
  ADDITIONAL THUNDERSTORMS WITH HEAVY RAIN MOVING INTO THE AREA
  OF WESTERN ALLEGANY COUNTY...THE THUNDERSTORMS WERE MOVING
  NORTHEAST AT 20 MPH.

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS AND STREAMS AND OTHER
LOW LYING AREAS ARE SUBJECT TO FLASH FLOODING.

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. VEHICLES CAUGHT IN RISING WATER SHOULD BE ABANDONED QUICKLY.
MOVE TO HIGHER GROUND.

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. IF YOUR VEHICLE STALLS, ABANDON IT IMMEDIATELY AND SEEK
HIGHER GROUND.

TO REPORT SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE FORECAST
OFFICE IN STERLING VIRGINIA.

LAT...LON 3950 7918 3945 7901 3973 7847 3993 7871

JLW

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Baltimore/Washington wrote its last area forecast discussion before this flash flood warning went out at Jul 31, 3:20 PM EDT, 1 hour 22 minutes earlier.

Area forecast discussion, Jul 31, 3:20 PM EDT, 1 hour 22 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
320 PM EDT MON JUL 31 2000

FLORIDA WEATHER HAS COME TO THE MID ATL STATES WITH TMPS IN THE 80S
AND DWPTS IN THE 70S...AND IT/S NOT LEAVING SOON. PERSISTENCE FORECAST
WILL WORK OUT JUST FINE FOR THIS PACKAGE. SLW MOVNG SCATTERED SHWRS
AND TSTMS WITH HEAVY RAIN WILL BE AROUND THROUGH THE WEEK. TROPICAL
PLUME EVIDENCED ON THE WV LOOP INDICATES DEEP MOISTURE AND PW VALS
ARE BTWN 1.5 AND TWO INCHES. NOT MUCH IN THE WAY OF FORCING...BUT
RIDGE LINES AND WEAK IMPULSES WILL BE ENUF FOR RNDM CONVCTN...MAINLY
DURING THE AFTERNOON AND EVENING HOURS.

EXTNDED PROGS HAVE A DRIER CANADIAN HGH PRES AREA MOVING IN LATE
SAT. MRF MOS GUIDANCE SHWS REMARKABLE DAY TO DAY CONSISTENCY THRU
THE WEEK.

STRONG
FCSTID = 78
DCA   70  85  70  87 /  40  40  40  40
BWI   70  85  70  87 /  40  40  40  40
MRB   70  85  70  87 /  40  40  40  40
IAD   70  85  70  87 /  40  40  40  40
CHO   70  85  70  87 /  40  40  40  40
HGR   70  85  70  87 /  40  40  40  40
NHK   70  85  70  87 /  40  40  40  40

.LWX...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.

The office that day

Everything else NWS Baltimore/Washington issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 31, 4:51 PM EDTTornado WarningLWXSaint Mary's39 min
Jul 31, 5:08 PM EDTTornado WarningLWXCalvert52 min

Nearby

Flash Flood Warnings in Maryland, 2000Every flash flood warning in 2000

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.