Alert archive / Georgia / Tornado Watches in 2009

Tornado Watch 90

March 28, 200928 counties in Georgia; 15 counties in South Carolina

The Storm Prediction Center issued this tornado watch at Mar 28, 2009, 12:47 PM EDT for 28 counties in Georgia; 15 counties in South Carolina. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Mar 28, 2009, 12:47 PM EDT (16:47 UTC)
Expired
Mar 28, 2009, 8:00 PM EDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 43 counties

Appling County, GA, Atkinson County, GA, Bacon County, GA, Brantley County, GA, Bryan County, GA, Bulloch County, GA, Burke County, GA, Camden County, GA, Candler County, GA, Charlton County, GA, Chatham County, GA, Clinch County, GA, Coffee County, GA, Echols County, GA, Effingham County, GA, Evans County, GA, Glynn County, GA, Jeff Davis County, GA, Jenkins County, GA, Liberty County, GA, Long County, GA, McIntosh County, GA, Pierce County, GA, Richmond County, GA, Screven County, GA, Tattnall County, GA, Ware County, GA, Wayne County, GA, Aiken County, SC, Allendale County, SC, Bamberg County, SC, Barnwell County, SC, Beaufort County, SC, Berkeley County, SC, Calhoun County, SC, Charleston County, SC, Clarendon County, SC, Colleton County, SC, Dorchester County, SC, Hampton County, SC, Jasper County, SC, Orangeburg County, SC, Sumter County, SC

The radar

The Charleston,SC radar (KCLX), 60 km from the middle of the area, began a volume at 16:50 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 SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

17 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Mar 28, 2:01 PM EDTSevere Thunderstorm WarningJAXCoffee, Jeff Davis44 min
Mar 28, 3:32 PM EDTSevere Thunderstorm WarningJAXCoffee, Jeff Davis43 min
Mar 28, 3:56 PM EDTSevere Thunderstorm WarningCHSColleton, Dorchester49 min
Mar 28, 4:01 PM EDTTornado WarningCHSBryan, Chatham, Effingham29 min
Mar 28, 4:12 PM EDTSevere Thunderstorm WarningJAXAppling, Bacon, Coffee, Jeff Davis, Wayne48 min
Mar 28, 4:26 PM EDTSevere Thunderstorm WarningCHSEvans, Long, Tattnall64 min
Mar 28, 4:26 PM EDTSevere Thunderstorm WarningCHSBeaufort, Charleston, Colleton, Hampton, Jasper34 min
Mar 28, 4:33 PM EDTSevere Thunderstorm WarningCAEOrangeburg57 min
Mar 28, 4:40 PM EDTSevere Thunderstorm WarningCHSBerkeley, Charleston, Colleton, Dorchester65 min
Mar 28, 4:51 PM EDTSevere Thunderstorm WarningJAXAppling, Bacon, Pierce, Wayne39 min
Mar 28, 4:57 PM EDTSevere Thunderstorm WarningCHSCharleston, Colleton, Dorchester33 min
Mar 28, 4:58 PM EDTSevere Thunderstorm WarningCAEClarendon77 min
Mar 28, 5:05 PM EDTTornado WarningCAEClarendon, Orangeburg55 min
Mar 28, 5:34 PM EDTTornado WarningCHSLiberty, Long, McIntosh41 min
Mar 28, 5:40 PM EDTSevere Thunderstorm WarningCHSBryan, Bulloch, Chatham, Effingham, Liberty50 min
Mar 28, 5:43 PM EDTTornado WarningCHSBryan, Chatham, Liberty47 min
Mar 28, 5:47 PM EDTSevere Thunderstorm WarningJAXAtkinson, Clinch, Coffee, Jeff Davis, Ware43 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Charleston AFB, SC (KCHS), launched 12:00Z, 4.8 hours before the alert went out and 158 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, Charleston AFB, SC at 12:00Z on 2009-03-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 18 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, Charleston AFB, SC at 12:00Z on 2009-03-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 84 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
18 J/kg
Mixed-layer CIN
-65 J/kg
Mixed-layer LCL
857 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
84 m²/s²
0-3 km storm-relative helicity
60 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

771 
WWUS20 KWNS 281649
SEL0  
SPC WW 281649
GAZ000-SCZ000-CWZ000-290000-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 90
NWS STORM PREDICTION CENTER NORMAN OK
1250 PM EDT SAT MAR 28 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       SOUTHEAST GEORGIA
       CENTRAL AND COASTAL SOUTH CAROLINA
       COASTAL WATERS

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 1250 PM UNTIL
800 PM EDT.

TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE
MILES EAST AND WEST OF A LINE FROM 40 MILES NORTH NORTHWEST OF
CHARLESTON SOUTH CAROLINA TO 30 MILES EAST SOUTHEAST OF VALDOSTA
GEORGIA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 89...

DISCUSSION...A LARGE CONVECTIVE CLUSTER WITH AN EMBEDDED MCV WILL
LIKELY PERSIST THROUGH THE AFTERNOON WHILE MOVING NEWD FROM GA INTO
SC.  INSTABILITY IS NOT PARTICULARLY STRONG E OF THE ONGOING
STORMS...BUT SOME MOISTENING AND CONTINUED SURFACE HEATING SHOULD
RESULT IN SUFFICIENT DESTABILIZATION TO MAINTAIN THE CLUSTER.  GIVEN
THE ORGANIZED BOWING SEGMENTS AND MODERATELY STRONG VERTICAL
SHEAR...A COUPLE OF TORNADOES WILL BE POSSIBLE IN ADDITION TO
DAMAGING WINDS.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
MEAN STORM MOTION VECTOR 24035.


...THOMPSON

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 28, 2:17 AM EDTTornado WatchSPCDecatur, Early, Miller, Seminole4 hr
Mar 28, 5:25 AM EDTMesoscale DiscussionSPCBaker, Ben Hill, Berrien, Brooks, Calhoun, Clay and 22 more35 min
Mar 28, 5:50 AM EDTTornado WatchSPCBaker, Ben Hill, Berrien, Brooks, Calhoun, Clay and 20 more5 hr
Mar 28, 7:48 AM EDTMesoscale DiscussionSPCAtkinson, Baker, Ben Hill, Berrien, Bibb, Bleckley and 53 more57 min
Mar 28, 10:20 AM EDTTornado WatchSPCBaker, Baldwin, Ben Hill, Berrien, Bibb, Bleckley and 48 more8 hr
Mar 28, 11:51 AM EDTMesoscale DiscussionSPCAppling, Atkinson, Bacon, Bryan, Bulloch, Burke and 21 more54 min
Mar 28, 3:19 PM EDTMesoscale DiscussionSPCAppling, Atkinson, Bacon, Ben Hill, Berrien, Brantley and 29 more56 min
Mar 28, 4:53 PM EDTMesoscale DiscussionSPCClarendon, Darlington, Dillon, Florence, Georgetown, Horry and 4 more67 min
Mar 28, 5:38 PM EDTTornado WatchSPCDarlington, Dillon, Florence, Georgetown, Horry, Marion and 2 more6 hr

Nearby

Tornado Watches in Georgia, 2009Tornado Watches in South Carolina, 2009Every tornado watch 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.