Alert archive / North Carolina / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 301, NWS Raleigh, NC

August 17, 2009Durham County, Orange County, Person County, North Carolina

NWS Raleigh, NC issued this severe thunderstorm warning at Aug 17, 2009, 2:48 PM EDT for Durham County, Orange County, Person County, North Carolina. 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
Aug 17, 2009, 2:48 PM EDT (18:48 UTC)
Expired
Aug 17, 2009, 3:30 PM EDT
In force
42 min
Issued by
NWS Raleigh, NC
Area
Storm-based polygon

Counties Durham County, NC, Orange County, NC, Person County, NC

The radar

The Raleigh/Durham radar (KRAX), 71 km from the middle of the area, began a volume at 19:05 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 nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 6.8 hours before the alert went out and 82 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, Greensboro/Hi Pt, NC at 12:00Z on 2009-08-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1792 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, Greensboro/Hi Pt, NC at 12:00Z on 2009-08-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -2 square meters per square second.1939Sfc1 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
1792 J/kg
Mixed-layer CIN
-14 J/kg
Mixed-layer LCL
661 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
-2 m²/s²
0-3 km storm-relative helicity
22 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

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 Raleigh, NC wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 17, 11:13 AM EDT, 3 hours 35 minutes earlier.

Area forecast discussion, Aug 17, 11:13 AM EDT, 3 hours 35 minutes before
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Hazardous weather outlook, Aug 17, 4:13 AM EDT, 10 hours 35 minutes before
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In the hours before

Special weather statement, Aug 17, 2:14 PM EDT, 34 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
214 PM EDT MON AUG 17 2009

NCZ008-024>026-041-171945-
DURHAM-FRANKLIN-GRANVILLE-ORANGE-WAKE-
214 PM EDT MON AUG 17 2009

...ISOLATED THUNDERSTORMS DEVELOPING ACROSS THE TRIANGLE...

AT 210 PM EDT...DOPPLER RADAR SHOWED DEVELOPING THUNDERSTORMS WITH
VERY HEAVY RAIN ACROSS EASTERN ORANGE...CENTRAL DURHAM AND NORTHERN
WAKE COUNTIES. THESE SHOWERS AND THUNDERSTORMS WERE MOVING EAST AT
20 MPH.

THE STRONGEST THUNDERSTORM WITH VERY HEAVY RAIN ALONG WITH SMALL
HAIL AND GUSTY WINDS WILL MOVE NEAR BETHESDA...GORMAN...FALLS
LAKE...PURNELL...WAKE FOREST THROUGH 315 PM.

BLAES
Special weather statement, Aug 17, 2:36 PM EDT, 12 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
236 PM EDT MON AUG 17 2009

NCZ075-171930-
MOORE-
236 PM EDT MON AUG 17 2009

...A STRONG THUNDERSTORM WILL MOVE ACROSS MOORE COUNTY THROUGH 330 PM
EDT...

AT 235 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER
TAYLORTOWN...OR ABOUT 8 MILES SOUTHWEST OF CARTHAGE...MOVING SLOWLY
EAST AT 5 MPH.

SOME LOCATIONS AFFECTED BY THIS STORM INCLUDE...TAYLORTOWN...
PINEHURST...WHISPERING PINES.

GUSTY WINDS OF 30 TO 40 MPH...SMALL HAIL AND DANGEROUS
CLOUD-TO-GROUND LIGHTNING CAN BE EXPECTED WITH THESE THUNDERSTORMS.

IN ADDITION...VERY HEAVY RAIN WITH RAINFALL RATES EXCEEDING
EXCEEDING ONE INCH DURING THE NEXT HOUR CAN BE EXPECTED IN THESE
AREAS. MOTORISTS SHOULD DRIVE WITH CAUTION TO AVOID HYDROPLANING.

SMITH

The office that day

Everything else NWS Raleigh, NC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 17, 3:07 PM EDTAreal Flood AdvisoryRAHMoore100 min
Aug 17, 3:15 PM EDTSevere Thunderstorm WarningRAHHoke, Scotland60 min
Aug 17, 3:25 PM EDTSevere Thunderstorm WarningRAHChatham, Lee51 min
Aug 17, 3:53 PM EDTAreal Flood AdvisoryRAHWake86 min
Aug 17, 4:14 PM EDTAreal Flood AdvisoryRAHOrange39 min
Aug 17, 4:28 PM EDTSevere Thunderstorm WarningRAHRichmond, Scotland39 min
Aug 17, 4:36 PM EDTSevere Thunderstorm WarningRAHJohnston, Wake39 min
Aug 17, 4:45 PM EDTAreal Flood AdvisoryRAHWake61 min
Aug 17, 4:49 PM EDTAreal Flood AdvisoryRAHRichmond, Scotland43 min
Aug 17, 4:52 PM EDTSevere Thunderstorm WarningRAHGranville, Vance38 min

Nearby

Severe Thunderstorm Warnings in North Carolina, 2009Every severe thunderstorm warning in 2009

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.