Alert archive / Virginia / Severe Thunderstorm Warnings in 2002
Severe Thunderstorm Warning 157, NWS Baltimore/Washington
NWS Baltimore/Washington issued this severe thunderstorm warning at Jul 27, 2002, 2:23 PM EDT for 7 counties in Virginia. It was in force for 52 min. 3 reports 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 27, 2002, 2:23 PM EDT (18:23 UTC)
- Expired
- Jul 27, 2002, 3:15 PM EDT
- In force
- 52 min
- Issued by
- NWS Baltimore/Washington
- Area
- Whole counties
Counties City of Fairfax, VA, City of Manassas, VA, City of Manassas Park, VA, Fairfax County, VA, Fauquier County, VA, Loudoun County, VA, Prince William County, VA
The radar
The Sterling radar (KLWX), 17 km from the middle of the area, began a volume at 18:25 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
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 27, 2:40 PM EDT | Thunderstorm Wind | Broad Run, VA | Trees were downed. |
| Jul 27, 2:47 PM EDT | Thunderstorm Wind | Warrenton, VA | Wires were downed. |
| Jul 27, 3:07 PM EDT | Thunderstorm Wind | Centreville, VA | Large tree limbs 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 nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 6.4 hours before the alert went out and 16 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.
- Mixed-layer CAPE
- 116 J/kg
- Mixed-layer CIN
- -98 J/kg
- Mixed-layer LCL
- 579 m above ground
- 0-6 km bulk shear
- 18 kt
- 0-1 km storm-relative helicity
- 65 m²/s²
- 0-3 km storm-relative helicity
- 128 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 27, 10:02 AM EDT, 4 hours 21 minutes earlier.
Area forecast discussion, Jul 27, 10:02 AM EDT, 4 hours 21 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON 1002 AM EDT SAT JUL 27 2002 HV ISSD FFA FOR W MD...E WV PANHANDLE AND HIGHLAND COUNTY VA. RECVD RPT OF OVR 3 IN OF RA IN GRANT COUNTY FM YEST. ADDITIONAL 1-2 IN OCCURRED OVR POTOMAC HILNDS LAST NGT. SFC WRMFRONT WAS LOCATED ALG PA/MD STATE LN AT 13Z. 06Z MESO ETA SUGGESTS FRONT WL BCM DIFFUSE BY ERLY AFTN. MDL BRINGS S/W FM OH THRU NRN FA THIS AFTN. VIS SAT PIX DEPICTED CLRG TREND OVR WRN ZONES THIS AM. W/WRMFNT N OF FA...EXPECT LOW CLDS OVR RMNDR OF FA TO MIX OUT THIS AFTN AND AMS TO BCM INCRGLY UNSTABLE. APPCH OF S/W AND LEFTOVR BDRIES FM ERLIER CONVECTION WL PROVIDE FOCUS/LIFT FOR MORE CONVECTION THIS AFTN. H85 DWPTS WERE +15 DEG C AND HIGH H7 DWPTS WERE ADVECTING INTO RGN. THIS MOISTURE IN COMBINATION W/SFC DWPTS IN 70S AND PCP H20 OF 1.75 IN WL CAUSE SHRAS/TSRAS TO PRODUCE HVY RAFL. FLASH FLOOD THREAT WL BE HIEST IN WRN FA WHERE HVY RA OCCURRED YEST/LAST NGT. FFG IN THIS AREA WAS ARND 2 IN/HR. .LWX... DC...NONE. MD...FLOOD WATCH FOR SATURDAY FOR ZONE MDZ002. VA...FLOOD WATCH FOR SATURDAY FOR ZONE VAZ021. WV...FLOOD WATCH FOR SATURDAY FOR ZONES WVZ048>050...WVZ054>055. ARTHUR
The office that day
Everything else NWS Baltimore/Washington issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 27, 10:39 AM EDT | Flash Flood Warning | LWX | Grant | 111 min |
| Jul 27, 12:37 PM EDT | Flash Flood Warning | LWX | Grant | 3 hr |
Nearby
Severe Thunderstorm Warnings in Virginia, 2002Every severe thunderstorm warning in 2002
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.