Alert archive / Virginia / Severe Thunderstorm Warnings in 2000

Severe Thunderstorm Warning 11, NWS Baltimore/Washington

April 21, 20004 counties in Virginia

NWS Baltimore/Washington issued this severe thunderstorm warning at Apr 21, 2000, 1:32 PM EDT for 4 counties in Virginia. It was in force for 43 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
Apr 21, 2000, 1:32 PM EDT (17:32 UTC)
Expired
Apr 21, 2000, 2:15 PM EDT
In force
43 min
Issued by
NWS Baltimore/Washington
Area
Whole counties

Counties Culpeper County, VA, Fauquier County, VA, Spotsylvania County, VA, Stafford County, VA

The radar

The Sterling radar (KLWX), 61 km from the middle of the area, began a volume at 17:34 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 watch it was issued in

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

IssuedProductOfficeLasted
Apr 21, 12:00 PM EDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.5 hours before the alert went out and 61 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 2000-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2000-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 230 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
626 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
230 m²/s²
0-3 km storm-relative helicity
254 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

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 Apr 21, 10:40 AM EDT, 2 hours 52 minutes earlier.

Area forecast discussion, Apr 21, 10:40 AM EDT, 2 hours 52 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
1040 AM EDT THU APR 20 2000

PREV FCST HAS GUD HANDLE ON AFTN WX SITN. MANY FAVORABLE FACTORS WL BE
PRESENT TO SUPPORT TSTMS AND PSBL SVR TSTMS.

A VORT MX ROTATING ARND OH VLLY CUTOFF LOW WL MOV OUT OF ERN TN
VLLY AND INTO THE WRN FA BY 18Z. CLRG HAS BN OCCURRING OVR WRN PTNS
OF FA THIS AM CONSISTENT W/DRY SLOT PROGGED BY LAST FEW MDL RUNS.
AT 300 MB...MLDS DID NOT CAPTURE PSN OF 95 KT JET. MDLS HAD JET
CNTRD TOO FAR W OF ITS ACTUAL 12Z PSN OVR GA. SO...FAIRLY STG JET WL BE
MOVG INTO FA THIS AFTN AND RGN WL BE UNDER LF QUAD.

AS UPR LOW HEADS EWD...ATMOS WL CONT TO DESTABILIZE. MODIFIED AM SDNG
GIVES LI OF -5 DEG C. IN ADDITION...SDNG HAD GUD VEERING IN LOW LVLS
AND SRH WAS 221 M/SEC2.

SFC DWPTS WERE IN 50S TO LOWER 60S THIS AM AND 850 MB PLOT SHOWED
PLENTY OF RH.

SFC LOW HAS FORMED NR CHO THIS AM. PRESENCE OF LOW MAY KEEP NRN FA
IN THE CLDS THIS AFTN WHICH WUD INHIBIT INSTAB SOMEWHAT. IN SRN FA
HOWEVER...LOW WL INCR UVV/S.

THINK BEST CHC FOR SVR WX WL BE IN SW ZONES DUE TO CLRG...SFC LOW
AND PROXIMITY OF UPR DYNAMICS. HOWEVER...EXPECT ENTR FA TO HV
TSTMS THIS AF]TN.

LOW WL BE STACKED OVHD TONIGHT AND LINGER ON SAT WHICH WL PROLONG
THE PCPN.

.LWX...SCA MD PTN CHES BAY AND POTOMAC.

ARTHUR

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 21, 2:10 PM EDTSevere Thunderstorm WarningLWXPrince William50 min
Apr 21, 2:21 PM EDTSevere Thunderstorm WarningLWXSpotsylvania, City of Fredericksburg24 min
Apr 21, 2:10 PM EDTSevere Thunderstorm WarningLWXCharles, Prince George's50 min
Apr 21, 2:33 PM EDTTornado WarningLWXCharles27 min
Apr 21, 3:03 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Prince George's57 min
Apr 21, 3:03 PM EDTSevere Thunderstorm WarningLWXCharles57 min
Apr 21, 4:16 PM EDTSevere Thunderstorm WarningLWXHoward, Montgomery59 min
Apr 21, 4:39 PM EDTSevere Thunderstorm WarningLWXPrince George's36 min
Apr 21, 5:05 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Baltimore, City of Baltimore55 min

Nearby

Severe Thunderstorm Warnings in Virginia, 2000Every severe thunderstorm 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.