Alert archive / Virginia / Severe Thunderstorm Warnings in 1999
Severe Thunderstorm Warning 137, NWS Blacksburg, VA
NWS Blacksburg, VA issued this severe thunderstorm warning at Sep 7, 1999, 10:51 PM EDT for Halifax County, Virginia. It was in force for 49 min. 2 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
- Sep 7, 1999, 10:51 PM EDT (02:51 UTC)
- Expired
- Sep 7, 1999, 11:40 PM EDT
- In force
- 49 min
- Issued by
- NWS Blacksburg, VA
- Area
- Whole counties
County Halifax County, VA
The radar
The Roanoke radar (KFCX), 122 km from the middle of the area, began a volume at 02:51 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 |
|---|---|---|---|
| Sep 7, 11:15 PM EDT | Thunderstorm Wind | Halifax, VA | |
| Sep 7, 11:50 PM EDT | Thunderstorm Wind | Halifax, VA |
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
Roanoke, VA (KRNK), launched 00:00Z, 2.9 hours before the alert went out and 69 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
- 126 J/kg
- Mixed-layer CIN
- -28 J/kg
- Mixed-layer LCL
- 1827 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- 31 m²/s²
- 0-3 km storm-relative helicity
- 84 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
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 Blacksburg, VA wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 7, 9:15 PM EDT, 1 hour 36 minutes earlier.
Area forecast discussion, Sep 7, 9:15 PM EDT, 1 hour 36 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 915 PM EDT TUE SEP 7 1999 AXIS OF SHRTWV AND SFC TROF STILL PASSING THROUGH CWA THIS EVENING. WITH ARND 70 SFC DEW POINTS AND CAPES FM JUST OVR 1000 AT RNK TO 2800 IN GSO...MORE AND MORE TSRA ARE DEVELOPING BETWEEN LYH AND DAN. SO WL KEEP CHC IN UNTIL MID. BY THEN ACTIVITY SHUD BE E OF THE FA. OVERALL HOWEVER...SOUNDINGS SHOW THAT ALOT OF DRY AIR HAS MOVED IN ABV 8H. STILL EXPECT FOG IN THE SE WV COUNTIES BUT SHUD BE SHALLOW COMPARED TO THIS MORNING AND SHUD BURN OFF QUICKLY TOMORROW. NO CHANGES PLANNED TO REST OF FCST. .RNK VA...NONE. WV...NONE. NC...NONE. AMS
The office that day
Everything else NWS Blacksburg, VA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 7, 10:33 PM EDT | Flash Flood Warning | RNK | Charlotte | 87 min |
| Sep 7, 11:40 PM EDT | Severe Thunderstorm Warning | RNK | Halifax | 35 min |
Nearby
Severe Thunderstorm Warnings in Virginia, 1999Every severe thunderstorm warning in 1999
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.