Alert archive / Maryland / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 97, NWS Baltimore/Washington

July 1, 2001Calvert County, Saint Mary's County, Maryland

NWS Baltimore/Washington issued this severe thunderstorm warning at Jul 1, 2001, 6:43 PM EDT for Calvert County, Saint Mary's County, Maryland. It was in force for 47 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jul 1, 2001, 6:43 PM EDT (22:43 UTC)
Expired
Jul 1, 2001, 7:30 PM EDT
In force
47 min
Issued by
NWS Baltimore/Washington
Area
Whole counties

Counties Calvert County, MD, Saint Mary's County, MD

The radar

The Sterling radar (KLWX), 107 km from the middle of the area, began a volume at 22:44 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
Jul 1, 7:05 PM EDTThunderstorm WindCountywide, MDTrees and wires were downed.

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 1, 6:30 PM EDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.7 hours before the alert went out and 99 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, Washington/Dulle, VA at 12:00Z on 2001-07-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 737 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, Washington/Dulle, VA at 12:00Z on 2001-07-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 28 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
737 J/kg
Mixed-layer CIN
-52 J/kg
Mixed-layer LCL
1231 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
28 m²/s²
0-3 km storm-relative helicity
145 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.2

Open this sounding in Storm Lab

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 1, 2:35 PM EDT, 4 hours 8 minutes earlier.

Area forecast discussion, Jul 1, 2:35 PM EDT, 4 hours 8 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
235 PM EDT SUN JUL 1 2001

KPBZ/KCCX RADARS SHOWING SOLID LINE OF THUNDERSTORMS SAGGING SLOWLY
SOUTHWARD ACROSS CENTRAL PA. SEVERAL WARNINGS COMING OUT FROM
OFFICES TO THE NORTH. 18Z ANALYSIS SHOWING COLD FRONT EXTENDING FROM
EASTERN LAKE ONTARIO THROUGH CENTRAL OHIO.

THIS COLD FRONT PROGGED BY 12Z ETA AND AVN TO MOVE THROUGH THE AREA
DURING THE EARLY EVENING HOURS... AND 15Z RUC SHOWING NO DIFFERENCE
IN THE TREND. ETA AND NOW THE RUC ARE HINTING THAT THE LINE OF
STORMS TO THE NORTH WILL BREAK UP AS IT APPROACHES... DUE TO THE
FACT THAT THE WIND FIELDS OVER OUR AREA ARE NOT NEARLY AS FAVORABLE
AS THEY ARE TO THE NORTH AND THAT MAIN SHORT WAVE AND HEIGHT FALLS
REMAIN OVER PA. STILL... UNSTABLE AMS IN PLACE WITH LI VALUES
CURRENTLY IN THE -5 TO -7 RANGE. CONSIDERING STRENGTH OF SURFACE
BOUNDARY... WOULD EXPECT THAT AT LEAST SCATTERED THUNDERSTORMS WOULD
DEVELOP OVER OUR AREA DURING THE LATE AFTERNOON AND EARLY EVENING
HOURS. FORECAST SOUNDINGS CONTINUE TO SHOW POTENTIAL FOR
STRONG/SEVERE WIND GUSTS... WILL MENTION HARDER IN THE NORTH THAN
THE SOUTH.

CLEAR SKIES AND DRY AIR SHOULD WORK INTO THE AREA AFTER MIDNIGHT.
NEXT COUPLE OF DAYS LOOK VERY PLEASANT. MAY SEE SOME LOWS IN THE 40S
IN THE FAVORED VALLEYS OUT WEST MONDAY NIGHT.

NEXT CHANCE OF PRECIP APPEARS TO BE LATE TUESDAY NIGHT IN THE
WEST... AND WEDNESDAY THROUGH EARLY THURSDAY FOR THE ENTIRE AREA.
WARM ADVECTION AND WEAK SHORT WAVE MOVING ACROSS THE WEST LATE
TUESDAY NIGHT... FOLLOWED BY A COLD FRONT MOVING THROUGH THE AREA
WEDNESDAY AFTERNOON. HIGH PRESSURE BUILDING IN BEHIND THIS SYSTEM
RESULTING IN DRY WEATHER FOR THE REST OF THE EXTENDED.

DCA   63  78  61  81 /  50   0   0   0
BWI   58  78  55  81 /  40   0   0   0
MRB   57  76  51  80 /  30   0   0  10
IAD   57  78  52  81 /  40   0   0   0
CHO   64  78  55  82 /  50   0   0   0
HGR   58  75  50  79 /  30   0   0  10
NHK   64  77  58  82 /  50   0   0   0
W99   57  78  50  82 /  40   0   0  10

.LWX...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SCA FOR TIDAL POTOMAC AND MD PORTION OF CHESAPEAKE BAY.

MARGRAF!

In the hours before

Special weather statement, Jul 1, 4:44 PM EDT, 1 hour 59 minutes before
DCZ001-MDZ002>007-009>011-013-014-VAZ021-026>031-040>042-052>054-
WVZ048>055-020100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE-WASHINGTON
444 PM EDT SUN JUL 1 2001

SEVERE THUNDERSTORM WATCH NUMBER 492 IS IN EFFECT UNTIL 900 PM EDT FOR
THE FOLLOWING AREAS...

THE DISTRICT OF COLUMBIA

IN MARYLAND... ALLEGANY...ANNE ARUNDEL...CARROLL...FREDERICK...
HARFORD...HOWARD...MONTGOMERY...NORTHERN BALTIMORE...PRINCE
GEORGES...SOUTHERN BALTIMORE AND WASHINGTON

IN VIRGINIA... ARLINGTON/FALLS CHURCH/ALEXANDRIA...CLARKE...
FAIRFAX...FAUQUIER...FREDERICK...HIGHLAND...LOUDOUN...PAGE...PRINCE
WILLIAM/MANASSAS/MANASSAS PARK...RAPPAHANNOCK...ROCKINGHAM...
SHENANDOAH AND WARREN

IN WEST VIRGINIA... BERKELEY...GRANT...HAMPSHIRE...HARDY...
JEFFERSON...MINERAL...MORGAN AND PENDLETON

A LINE OF STRONG THUNDERSTORMS OVER SOUTHERN PENNSYLVANIA AND WESTERN
MARYLAND WILL MOVE THROUGH THE WATCH AREA DURING THE LATE AFTERNOON AND
EARLY EVENING HOURS. THE MAIN THREAT FROM THESE STORMS WILL BE DAMAGING
WIND. VERY HEAVY DOWNPOURS AND LARGE HAIL ARE ALSO POSSIBLE.

MARGRAF!
Special weather statement, Jul 1, 6:39 PM EDT, 4 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jul 1, 4:51 PM EDTSevere Thunderstorm WarningLWXPrince William, City of Manassas, City of Manassas Park39 min
Jul 1, 4:51 PM EDTSevere Thunderstorm WarningLWXFauquier39 min
Jul 1, 5:28 PM EDTSevere Thunderstorm WarningLWXFairfax, Prince William47 min
Jul 1, 5:28 PM EDTSevere Thunderstorm WarningLWXCity of Manassas47 min
Jul 1, 5:28 PM EDTSevere Thunderstorm WarningLWXFauquier47 min
Jul 1, 6:14 PM EDTSevere Thunderstorm WarningLWXLoudoun46 min
Jul 1, 3:49 PM EDTSevere Thunderstorm WarningLWXBaltimore, City of Baltimore41 min
Jul 1, 3:49 PM EDTSevere Thunderstorm WarningLWXCarroll41 min
Jul 1, 5:59 PM EDTSevere Thunderstorm WarningLWXCharles46 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2001Every 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.