Alert archive / Virginia / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 99, NWS Baltimore/Washington

July 4, 2001Loudoun County, Virginia; Frederick County, Maryland

NWS Baltimore/Washington issued this severe thunderstorm warning at Jul 4, 2001, 3:48 PM EDT for Loudoun County, Virginia; Frederick County, Maryland. It was in force for 42 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 4, 2001, 3:48 PM EDT (19:48 UTC)
Expired: Jul 4, 2001, 4:30 PM EDT
In force: 42 min
Issued by: NWS Baltimore/Washington
Area: Whole counties

Counties Frederick County, MD, Loudoun County, VA

The radar

The Sterling radar (KLWX), 34 km from the middle of the area, began a volume at 19:48 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 text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Jul 4, 2:45 PM EDT, 1 hour 3 minutes earlier.

Area forecast discussion, Jul 4, 2:45 PM EDT, 1 hour 3 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
245 PM EDT WED JUL 4 2001

ERN U.S. TROF WILL AMPLIFY ONCE AGAIN OVR THE NEXT COUPLE OF DAYS AS
A CUTOFF LOW DROPS SEWD THEN EWD THRU SE CANADA. UPR LVL TROF WILL
BEGIN TO LIFT OUT SAT AS UPR LVL RIDGE OVR THE CENTRAL U.S. STARTS
TO NUDGE EWD A BIT.

AT THE SFC...A TROF WILL PUSH THRU THE AREA THIS EVENING FOLLOWED BY
THE MAIN CDFNT THU AFT/EVE.

BEST MOISTURE CONVERGENCE AND INSTABILITY WILL BE ALG AND JUST AHD
OF THE SFC TROF EARLY TNGT. WILL GO CHC POPS THIS EVE FOR SHRA/TSRA
AS THE SFC TROF MOVES W TO E ACRS THE AREA.

MUCH OF THE MOISTURE AND INSTABILITY WILL BE SWEPT E OF THE AREA
TNGT WITH THE SFC TROF. W FLOW BEHIND THE TROF WILL DRY US OUT LATER
TNGT AND THU. LOW-LVL FORCING WL BE MARGINAL WITH THE CDFNT THU
AFT/EVE AS THE LOW-LVL FLOW NEVER COMPLETELY BACKS AROUND. AIR MASS
WILL NOT BE AS MOIST AND UNSTABLE AND W DOWNSLOPING FLOW WILL TEND
TO SUPRESS ACTIVITY. IN ADDITION...BUFKIT SOUNDINGS FM THE ETA SHOW
A CAP IN PLACE. HOWEVER...GIVEN THE FACT THAT THE CDFNT WILL COME
THRU DURING MAX HEATING WILL LEAVE 30 POPS IN PLACE JUST IN CASE A
FEW TSRA FORM ALG THE BOUNDARY.

SFC HIGH PRES BUILDS INTO THE AREA THU NIGHT AND FRI WITH A COOLER
AND DRIER AIR MASS. WILL GO M/CLR THU NIGHT AND SUNNY ON FRI.

RETURN FLOW ON BACKSIDE OF THE HIGH FOR SAT. MOIST AND MORE UNSTABLE
AIR MASS WILL RESULT IN SCT AFT/EVE TSRA AHEAD OF A CDFNT WHICH WILL
MOVE THRU THE AREA SAT NIGHT/EARLY SUN.

FCSTID = 15 / DMW

DCA   70  87  61  80 /  50  30  10   0
BWI   67  85  56  80 /  50  30  10   0
MRB   63  82  54  80 /  50  30  10   0
IAD   64  86  54  80 /  50  30  10   0
CHO   68  86  59  81 /  50  30  10   0
HGR   62  82  52  79 /  50  30  10   0
NHK   70  85  63  79 /  50  30  10   0
W99   58  82  48  80 /  30  30  10   0

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

In the hours before

Special weather statement, Jul 4, 10:50 AM EDT, 4 hours 58 minutes before

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Nearby

Severe Thunderstorm Warnings in Virginia, 2001 Severe Thunderstorm Warnings in Maryland, 2001 Every severe thunderstorm warning in 2001

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.