Alert archive / Arkansas / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 172, NWS Shreveport, LA

May 10, 2009Nevada County, Arkansas

NWS Shreveport, LA issued this severe thunderstorm warning at May 10, 2009, 3:21 AM CDT for Nevada County, Arkansas. It was in force for 54 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: May 10, 2009, 3:21 AM CDT (08:21 UTC)
Expired: May 10, 2009, 4:15 AM CDT
In force: 54 min
Issued by: NWS Shreveport, LA
Area: Storm-based polygon

County Nevada County, AR

The radar

The Shreveport radar (KSHV), 144 km from the middle of the area, began a volume at 08:22 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

Shreveport, LA (KSHV), launched 00:00Z, 8.4 hours before the alert went out and 138 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1854 J/kg
Mixed-layer CIN: -40 J/kg
Mixed-layer LCL: 737 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 80 m²/s²
0-3 km storm-relative helicity: 164 m²/s²
Significant tornado parameter: 1.5
Supercell composite: 8.2

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 Shreveport, LA wrote its last area forecast discussion before this severe thunderstorm warning went out at May 9, 10:30 PM CDT, 4 hours 51 minutes earlier.

Area forecast discussion, May 9, 10:30 PM CDT, 4 hours 51 minutes before

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SHREVEPORT LA
1030 PM CDT SAT MAY 9 2009

...A QUICK UPDATE TO THE FORECAST WILL BE COMING...

.DISCUSSION...
PLENTY OF RAINDROPS CONTINUE TO FALL ON THE HEADS OF RESIDENTS
ACROSS NORTHEASTERN TEXAS AND SOUTHERN ARKANSAS...AS A FRONT REMAINS
NEARLY STATIONARY NEAR THE IH-20 CORRIDOR.  CONVECTIVE COVERAGE HAS
DECREASED SOMEWHAT OVER THIS REGION...AT LEAST TEMPORARILY.  I
EXPECT ADDITIONAL ELEVATED CONVECTION TO DEVELOP OVERNIGHT ACROSS
THIS REGION AS BOUNDARY LAYER MOISTURE CONTINUES INTERACTING WITH
ISENTROPIC UPGLIDE.

A LACK OF STRONG FORCING OF INSTABILITY SHOULD KEEP MOST
THUNDERSTORMS /SURFACE-BASED OR OTHERWISE/ AT BAY OVERNIGHT.  ANY OF
THE STRONGER STORMS MAY BE CAPABLE OF PRODUCING SOME HAIL.

WITH THIS UPDATE I HAVE ADJUSTED FIRST PERIOD PRECIPITATION
PROBABILITIES TO BRING THEM INTO BETTER ALIGNMENT WITH OBSERVED
TRENDS.  FLASH FLOODING REMAINS A GOOD BET IN SEVERAL AREAS
OVERNIGHT DUE TO TRAINING CONVECTION AND SOGGY GROUND CONDITIONS.
IN FACT...A COCORAHS OBSERVER IN BOWIE COUNTY HAS REPORTED OVER 5
INCHES OF RAINFALL SINCE THE RAIN BEGAN.

I HAVE ALSO MADE SOME ADJUSTMENTS TO THE SKY COVER...AS WELL AS
HOURLY TEMPERATURE AND DEWPOINT GRIDS.  THIS HAS RESULTED IN SOME
ADJUSTMENT OF OVERNIGHT LOW TEMPERATURES.

ISC GRIDS HAVE BEEN SENT AND SHOULD BE POSTED TO THE INTERNET.  AN
UPDATED SUITE OF PRODUCTS WILL BE ISSUED SHORTLY.  /21/

&&

.PREV DISCUSSION... /ISSUED 812 PM CDT SAT MAY 9 2009/

..A QUICK UPDATE TO THE FORECAST WILL BE COMING...

DISCUSSION...
FRONT HAS ALL BUT STALLED NEAR THE IH-20 CORRIDOR EARLY THIS
EVENING.  SHOWERS AND THUNDERSTORMS CONTINUE TO BE SEEN NORTH OF
THIS BOUNDARY...AND SOUTH OF THE THE 850MB FRONT /CLOSER TO THE
IH-40 CORRIDOR/.  CONVECTION SHOULD CONTINUE FROM NORTHEAST TEXAS
INTO SOUTH ARKANSAS AT LEAST FOR THE NEXT SEVERAL HOURS.  IN
GENERAL...IT LOOKS LIKE THE SEVERE WEATHER RISK IS JUST ABOUT OVER
THE NORTHERN TIER OF COUNTIES.  INSTABILITY AND MOISTURE REMAIN HIGH
OVER SOUTHERN AREAS...BUT THE EVENING SOUNDING SHOWS A STRONG
CAPPING INVERSION REMAINING IN PLACE.

THAT SAID...I WILL UPDATE THE FORECAST TO REMOVE SEVERE THUNDERSTORM
WATCH 282.  FLASH FLOODING REMAINS A RISK OVER NORTHERN AREAS THANKS
TO TRAINING...AND THE FLASH FLOOD WATCH WILL REMAIN IN EFFECT FOR
THE TIME BEING.

FOR NOW...I WILL NOT MAKE ANY CHANGES TO THE ONGOING FORECAST.  I
MAY MAKE A FEW ADJUSTMENTS LATER THIS EVENING TO THE SENSIBLE
WEATHER ELEMENTS BASED ON OBSERVED TRENDS.  UPDATES MAY BE SENT FOR
THIS LATER.  I WOULD JUST LIKE TO SEE HOW TEMPERATURES/DEWPOINTS
TREND IN SOME OF THE RAIN-COOLED AREAS BEFORE TWEAKING TOO MUCH ONE
WAY OR THE OTHER.

ISC GRIDS HAVE BEEN SENT AND SHOULD BE POSTED TO THE INTERNET.  AN
UPDATED SUITE OF PRODUCTS WILL BE ISSUED SHORTLY.  /21/

AVIATION...
MAINLY VFR FLIGHT CATEGORIES ARE EXPECTED S OF IH-20...WITH POSSIBLE
REDUCTIONS TO MVFR BETWEEN 10/0900-1400 UTC OR SO.  WIDESPREAD
MVFR/IFR FLIGHT CATEGORIES WILL BE PREVALENT AT MOST OTHER TERMINALS
WITH FURTHEY EVENING FOR THE FOLLOWING
     ZONES: ARZ050-051-059>061-070>073.

LA...NONE.
OK...FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR THE FOLLOWING
     ZONES: OKZ077.

TX...FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR THE FOLLOWING
     ZONES: TXZ096-097.

&&

D. BUTTS

Hazardous weather outlook, May 9, 11:46 AM CDT, 15 hours 35 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SHREVEPORT LA
1146 AM CDT SAT MAY 9 2009

ARZ050-051-059>061-070>073-LAZ001>006-010>014-OKZ077-TXZ096-097-
108>112-124>126-136>138-149>151-101200-
SEVIER-HOWARD-LITTLE RIVER-HEMPSTEAD-NEVADA-MILLER-LAFAYETTE-
COLUMBIA-UNION AR-CADDO-BOSSIER-WEBSTER-CLAIBORNE-LINCOLN-
UNION LA-DE SOTO-RED RIVER-BIENVILLE-JACKSON-OUACHITA-MCCURTAIN-
BOWIE-FRANKLIN-TITUS-CAMP-MORRIS-CASS-WOOD-UPSHUR-MARION-SMITH-
GREGG-HARRISON-CHEROKEE-RUSK-PANOLA-
1146 AM CDT SAT MAY 9 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
ARKANSAS...SOUTHWEST ARKANSAS...NORTH CENTRAL LOUISIANA...
NORTHWEST LOUISIANA...SOUTHEAST OKLAHOMA AND NORTHEAST TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT...

STRONG TO SEVERE THUNDERSTORMS MAY DEVELOP EARLY THIS
AFTERNOON...ALONG AND NORTH OF I 20...WHERE A FRONTAL BOUNDARY
LIES. THE THREAT WILL SHIFT TO JUST SOUTH OF I 20 AS THE FRONT
SLOWLY DIPS SOUTHWARD THIS EVENING. STRONG INSTABILITY FROM
DAYTIME HEATING WILL AID IN THUNDERSTORM INITIATION THIS AFTERNOON.
EVEN WITH THE LOSS OF DAYTIME HEATING...EXPECT THUNDERSTORMS TO
CONTINUE AS THE LOW LEVEL JET KICKS IN TONIGHT...WITH LOCALLY
HEAVY RAINFALL AND THE POSSIBILITY FOR LARGE HAIL AND DAMAGING
WINDS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...

THE SEVERE WEATHER AND HEAVY RAINFALL THREAT WILL CONTINUE THROUGH
AT LEAST SUNDAY NIGHT. FLASH FLOODING WILL BE A POSSIBILITY...
CONSIDERING THE RAINFALL EARLIER IN THE MONTH.

ANOTHER STORM SYSTEM AND ASSOCIATED COLD FRONT WILL ARRIVE LATE ON
WEDNESDAY INTO THURSDAY WITH YET ANOTHER POSSIBILITY OF STRONG TO
SEVERE THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND TONIGHT.

LAZ017>022-TXZ152-153-165>167-101200-
SABINE LA-NATCHITOCHES-WINN-GRANT-CALDWELL-LA SALLE-NACOGDOCHES-
SHELBY-ANGELINA-SAN AUGUSTINE-SABINE TX-
1146 AM CDT SAT MAY 9 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
LOUISIANA...NORTHWEST LOUISIANA AND EAST TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT...

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MAY DEVELOP THIS
AFTERNOON...AS A SOUTHWARD MOVING COLD FRONT ENTERS A MODERATELY
UNSTABLE ENVIRONMENT. THIS ACTIVITY WILL LIKELY DISSIPATE SHORTLY
AFTER SUNSET.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...

THUNDERSTORMS ARE EXPECTED TO DEVELOP ONCE AGAIN SUNDAY AND
MONDAY...AS THE FRONTAL BOUNDARY CONTINUES TO SLOWLY PUSH
SOUTHWARD. SOME STORMS MAY REACH SEVERE LIMITS...WITH LARGE HAIL
AND DAMAGING WINDS AS THE MAIN THREATS.

ANOTHER STORM SYSTEM AND ASSOCIATED COLD FRONT WILL ARRIVE LATE ON
WEDNESDAY INTO THURSDAY WITH YET ANOTHER POSSIBILITY OF STRONG TO
SEVERE THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL LIKELY NOT BE NEEDED THIS AFTERNOON OR TONIGHT.

12

In the hours before

Special weather statement, May 10, 12:33 AM CDT, 2 hours 48 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
1233 AM CDT SUN MAY 10 2009

ARZ050-051-OKZ077-100630-
HOWARD-MCCURTAIN-SEVIER-
1233 AM CDT SUN MAY 10 2009

...SIGNIFICANT WEATHER ALERT...

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A SIGNIFICANT
WEATHER ALERT...EFFECTIVE UNTIL 130 AM CDT...FOR THE FOLLOWING
COUNTIES...

IN SOUTHWEST ARKANSAS...
     SEVIER AND HOWARD...
IN SOUTHEAST OKLAHOMA...
     MCCURTAIN...

INCLUDING THE FOLLOWING LOCATIONS...
     ATHENS...DE QUEEN...GILLHAM...UMPIRE AND BROKEN BOW...

AT 1231 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A STRONG THUNDERSTORM 11 MILES NORTHWEST OF DE QUEEN...MOVING NORTHEAST
AT 35 MPH. THIS STORM WILL ENTER EXTREME NORTHWEST SEVIER COUNTY JUST
WEST OF GILLHAM DURING THE NEXT FEW MINUTES.

ANOTHER STRONG THUNDERSTORM WAS INDICATED OVER BROKEN BOW...ALSO MOVING
NORTHEAST AT 35 MPH.

PEA TO HALF INCH DIAMETER HAIL IS EXPECTED WITH THESE STORMS. SHOULD
THESE STORMS INTENSIFY...A SEVERE THUNDERSTORM WARNING WILL BE NEEDED.

15

Local storm report, May 10, 1:17 AM CDT, 2 hours 4 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT LA
117 AM CDT SUN MAY 10 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0110 AM     HAIL             UMPIRE                  34.27N 94.05W
05/10/2009  E1.75 INCH       HOWARD             AR   LAW ENFORCEMENT

            GOLF BALL SIZE HAIL REPORTED IN UMPIRE.

&&

15

Special weather statement, May 10, 2:06 AM CDT, 1 hour 15 minutes before

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Special weather statement, May 10, 2:51 AM CDT, 30 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
251 AM CDT SUN MAY 10 2009

ARZ051-100815-
HOWARD-
251 AM CDT SUN MAY 10 2009

...SIGNIFICANT WEATHER ALERT...

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A SIGNIFICANT
WEATHER ALERT...EFFECTIVE UNTIL 315 AM CDT...FOR THE FOLLOWING
COUNTY...

IN SOUTHWEST ARKANSAS...
     HOWARD...

INCLUDING THE FOLLOWING LOCATIONS...
     CENTER POINT...CORINTH AND DIERKS...

AT 250 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM NEAR CENTER POINT...OR 5 MILES SOUTHEAST OF
DIERKS...MOVING EAST AT 20 MPH...AS IT AFFECTS MAINLY RURAL AREAS OF
EASTERN HOWARD COUNTY.

PEA SIZE HAIL AND WIND GUSTS OF 30 TO 40 MPH ARE EXPECTED WITH THIS STORM.

15

Local storm report, May 10, 2:54 AM CDT, 27 minutes before

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Local storm report, May 10, 3:05 AM CDT, 16 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT LA
305 AM CDT SUN MAY 10 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0300 AM     FLASH FLOOD      5 S DIERKS              34.05N 94.02W
05/10/2009                   HOWARD             AR   LAW ENFORCEMENT

            HIGH WATER REPORTED ACROSS HWY 278 BETWEEN DIERKS AND
            NASHVILLE.

0300 AM     FLASH FLOOD      W DIERKS                34.12N 94.02W
05/10/2009                   HOWARD             AR   LAW ENFORCEMENT

            HIGH WATER REPORTED WEST OF DIERKS ON HWY 70.

&&

MBERRY

The office that day

Everything else NWS Shreveport, LA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 9, 10:16 PM CDT	Flash Flood Warning	SHV	Bowie	3 hr
May 9, 10:21 PM CDT	Severe Thunderstorm Warning	SHV	Bowie	24 min
May 9, 10:41 PM CDT	Severe Thunderstorm Warning	SHV	Bowie	64 min
May 10, 1:05 AM CDT	Severe Thunderstorm Warning	SHV	Red River	55 min
May 10, 1:50 AM CDT	Severe Thunderstorm Warning	SHV	Red River	55 min
May 10, 2:05 AM CDT	Flash Flood Warning	SHV	Red River	12 hr
May 10, 6:31 AM CDT	Flash Flood Warning	SHV	Bowie	8 hr
May 10, 10:00 AM CDT	River Flood Warning	SHV	Bowie, Red River	6 days
May 10, 11:20 AM CDT	River Flood Warning	SHV	Bienville, Bossier, Red River, Webster	7 days
May 10, 11:22 AM CDT	River Flood Warning	SHV	Bienville, Bossier, Caddo, Natchitoches, Red River	6 days
May 10, 11:22 AM CDT	River Flood Warning	SHV	Grant, Natchitoches, Red River	10 days
May 10, 1:12 PM CDT	Severe Thunderstorm Warning	SHV	Winn	48 min
May 10, 3:16 PM CDT	Tornado Warning	SHV	Bienville, Jackson, Natchitoches, Red River, Winn	29 min
May 10, 3:43 PM CDT	Tornado Warning	SHV	Bienville, Jackson, Natchitoches, Winn	47 min
May 10, 4:29 PM CDT	Tornado Warning	SHV	Grant, Natchitoches, Winn	46 min
May 10, 4:55 PM CDT	Tornado Warning	SHV	Natchitoches, Red River	35 min
May 10, 5:18 PM CDT	Severe Thunderstorm Warning	SHV	Caldwell, Grant, LaSalle, Winn	42 min
May 10, 5:39 PM CDT	Severe Thunderstorm Warning	SHV	Bienville, Natchitoches, Red River	51 min
May 10, 6:07 PM CDT	Severe Thunderstorm Warning	SHV	De Soto, Natchitoches, Red River	38 min
May 10, 6:40 PM CDT	Severe Thunderstorm Warning	SHV	Caldwell	35 min
May 10, 12:58 AM CDT	Severe Thunderstorm Warning	SHV	Howard, Sevier	32 min
May 10, 2:36 AM CDT	Severe Thunderstorm Warning	SHV	Hempstead, Howard	54 min
May 10, 4:57 AM CDT	Severe Thunderstorm Warning	SHV	Hempstead, Little River	63 min
May 10, 5:38 AM CDT	Severe Thunderstorm Warning	SHV	Hempstead, Nevada	52 min
May 10, 7:26 AM CDT	Flash Flood Warning	SHV	Nevada	7 hr
May 10, 9:58 AM CDT	River Flood Warning	SHV	Howard, Little River, Sevier	6 days
May 10, 2:17 PM CDT	Flash Flood Warning	SHV	Hempstead, Howard, Little River, Sevier	4 hr
May 10, 4:03 PM CDT	Flash Flood Warning	SHV	Nevada	57 min

Nearby

Severe Thunderstorm Warnings in Arkansas, 2009 Every 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.