Alert archive / Louisiana / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 357, NWS Shreveport, LA

October 22, 20094 parishes in Louisiana

NWS Shreveport, LA issued this severe thunderstorm warning at Oct 22, 2009, 1:11 PM CDT for 4 parishes in Louisiana. It was in force for 49 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: Oct 22, 2009, 1:11 PM CDT (18:11 UTC)
Expired: Oct 22, 2009, 2:00 PM CDT
In force: 49 min
Issued by: NWS Shreveport, LA
Area: Storm-based polygon

Counties Bienville Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Winn Parish, LA

The radar

The Shreveport radar (KSHV), 106 km from the middle of the area, began a volume at 18:14 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Oct 22, 11:58 AM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 6.2 hours before the alert went out and 98 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: 294 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 469 m above ground
0-6 km bulk shear: 57 kt
0-1 km storm-relative helicity: 224 m²/s²
0-3 km storm-relative helicity: 250 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 2.7

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 Oct 22, 12:09 PM CDT, 1 hour 2 minutes earlier.

Area forecast discussion, Oct 22, 12:09 PM CDT, 1 hour 2 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
1209 PM CDT THU OCT 22 2009

...ANOTHER QUICK UPDATE TO THE FORECAST HAS BEEN MADE...

.DISCUSSION...
I HAVE UPDATED THE GRIDDED AND TEXT PRODUCTS IN ORDER TO
INCORPORATE TORNADO WATCH 772...VALID UNTIL 7 PM. NO OTHER CHANGES
WERE MADE AT THIS TIME.  /21/

&&

.PREV DISCUSSION... /ISSUED 901 AM CDT THU OCT 22 2009/

DISCUSSION...
COLD FRONT CONTINUES TO MAKE STEADY PROGRESS INTO THE FORECAST AREA
THIS MORNING...AND EXTENDS FROM COLLEGE STATION TEXAS TO MOUNT
HERMAN OKLAHOMA AS OF 8 AM.  THE FRONT SHOULD MOVE INTO NORTHWEST
LOUISIANA THIS AFTERNOON...AND THROUGH THE REGION THIS EVENING.
UNTIL THEN...PLENTY OF MOISTURE WILL COMBINE WITH AMPLE LIFT TO
PRODUCE WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ALONG AND
AHEAD OF THE FRONT.

FOR THE MOST PART...THE FORECAST PACKAGE LOOKS TO BE IN GOOD SHAPE.
IN LIGHT OF THE HEAVY RAINFALL TOTALS INDICATED BY AREA RADARS
ACROSS EAST TEXAS...I HAVE EXPANDED THE FLASH FLOOD WATCH TO
ENCOMPASS OUR ENTIRE FORECAST AREA.  THE EXPIRATION TIME WILL REMAIN
THE SAME...AND GOOD UNTIL 4 PM.  I HAVE ALSO UPDATED GRIDDED QPF
AMOUNTS BASED UPON THE LATEST GUIDANCE FROM THE HYDROMETEOROLOGICAL
PREDICTION CENTER.

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

AVIATION...
A COLD FRONT WILL PROGRESS THROUGH THE FOUR STATE REGION THROUGH THE
AFTERNOON AND EARLY EVENING HOURS. WIDESPREAD SHOWERS...ALONG WITH
EMBEDDED THUNDERSTORMS...WILL PERSIST AHEAD OF THE FRONT AS IT MOVES
EASTWARD. WIND GUSTS OF UP TO 25 KTS MAY BE POSSIBLE ACROSS AREA
TERMINALS...ASSOCIATED WITH EMBEDDED THUNDERSTORMS. WINDS WILL SHIFT
TO THE NORTHWEST BEHIND THE FRONT...AVERAGING AROUND 10 KTS.
OTHERWISE...CEILINGS WILL GRADUALLY IMPROVE ACROSS EAST TEXAS FROM
MVFR TO VFR LATE IN THE TERMINAL FORECAST PERIOD. /05/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  74  50  64  46  74 / 100  30  10  10  10
MLU  74  53  64  46  72 / 100  70  10  10  10
DEQ  66  42  62  38  71 /  80  20  10  10  10
TXK  68  49  63  46  70 /  90  30  10  10  10
ELD  72  49  64  44  71 / 100  50  10  10  10
TYR  69  45  66  48  75 /  90  10  10  10  10
GGG  72  46  65  46  72 /  90  20  10  10  10
LFK  74  48  68  44  77 /  90  20  10  10  10

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH UNTIL 4 PM CDT THIS AFTERNOON FOR THE
     FOLLOWING ZONES: ARZ050-051-059>061-070>073.

LA...FLASH FLOOD WATCH UNTIL 4 PM CDT THIS AFTERNOON FOR THE
     FOLLOWING ZONES: LAZ001>006-010>014-017>022.

OK...FLASH FLOOD WATCH UNTIL 4 PM CDT THIS AFTERNOON FOR THE
     FOLLOWING ZONES: OKZ077.

TX...FLASH FLOOD WATCH UNTIL 4 PM CDT THIS AFTERNOON FOR THE
     FOLLOWING ZONES:
     TXZ096-097-108>112-124>126-136>138-149>153-165>167.

&&

D. BUTTS

Hazardous weather outlook, Oct 22, 12:48 PM CDT, 23 minutes before

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In the hours before

Local storm report, Oct 22, 7:22 AM CDT, 5 hours 49 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT LA
722 AM CDT THU OCT 22 2009

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

0552 AM     FLASH FLOOD      QUITMAN                 32.80N 95.44W
10/22/2009                   WOOD               TX   BROADCAST MEDIA

            SEVERAL ROADS ARE CLOSED THROUGHOUT THE COUNTY DUE TO
            HIGH WATER.

0622 AM     FLASH FLOOD      2 SE NOONDAY            32.22N 95.37W
10/22/2009                   SMITH              TX   BROADCAST MEDIA

            FM2868 CLOSED DUE TO HIGH WATER.

0622 AM     FLASH FLOOD      13 NW LINDALE           32.64N 95.56W
10/22/2009                   SMITH              TX   BROADCAST MEDIA

            CR 455 CLOSED DUE TO HIGH WATER.

0625 AM     FLASH FLOOD      GILMER                  32.73N 94.95W
10/22/2009                   UPSHUR             TX   LAW ENFORCEMENT

            SEVERAL ROADS ARE FLOODED ACROSS THE COUNTY.

&&

15

Special weather statement, Oct 22, 9:22 AM CDT, 3 hours 49 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
922 AM CDT THU OCT 22 2009

TXZ151-153-221500-
PANOLA-SHELBY-
922 AM CDT THU OCT 22 2009

...SIGNIFICANT WEATHER ALERT...

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A SIGNIFICANT
WEATHER ALERT...EFFECTIVE UNTIL 1000 AM CDT...FOR THE FOLLOWING
COUNTIES...

IN NORTHEAST TEXAS...
     PANOLA...
IN EASTERN TEXAS...
     SHELBY...

INCLUDING THE FOLLOWING LOCATIONS...
     JOAQUIN AND TENAHA...

AT 922 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS ARE TRACKING
A STRONG THUNDERSTORM 6 MILES NORTHWEST OF CENTER...MOVING NORTH AT
20 MPH. SOME WEAK ROTATION WAS DETECTED WITH THIS STRONG THUNDERSTORM
AS IT MOVED NORTHEAST.

WINDS 40 TO 50 MPH ARE EXPECTED WITH THIS STORM.

13

Special weather statement, Oct 22, 9:26 AM CDT, 3 hours 45 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
926 AM CDT THU OCT 22 2009

TXZ153-166-221530-
SAN AUGUSTINE-SHELBY-
926 AM CDT THU OCT 22 2009

...SIGNIFICANT WEATHER ALERT...

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A SIGNIFICANT
WEATHER ALERT...EFFECTIVE UNTIL 1030 AM CDT...FOR THE FOLLOWING
COUNTIES...

IN EASTERN TEXAS...
     SHELBY AND SAN AUGUSTINE...

INCLUDING THE FOLLOWING LOCATIONS...
     BLAND LAKE...NEUVILLE AND SAN AUGUSTINE...

AT 925 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS ARE TRACKING
A STRONG THUNDERSTORM NEAR SAN AUGUSTINE...OR 20 MILES SOUTH OF
CENTER...MOVING NORTH AT 20 MPH. THIS THUNDERSTORM EXHIBITED SOME WEAK
ROTATION AS IT MOVED NORTHEAST.

WINDS 40 TO 50 MPH ARE EXPECTED WITH THIS STORM.

13

Local storm report, Oct 22, 12:39 PM CDT, 32 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT LA
1239 PM CDT THU OCT 22 2009

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

1220 PM     FLASH FLOOD      BENTON                  32.69N 93.74W
10/22/2009                   BOSSIER            LA   LAW ENFORCEMENT

            BOSSIER PARISH SHERIFFS OFFICE REPORTS SEVERAL HIGHWAYS
            ACROSS THE PARISH ARE UNDER WATER.

1225 PM     FLASH FLOOD      BOSSIER CITY            32.52N 93.66W
10/22/2009                   BOSSIER            LA   NWS EMPLOYEE

            AN NWS EMPLOYEE REPORTED MODERATE STREET FLOODING ALONG
            INTERSTATE HWY 220 AT SWAN LAKE RD.

&&

18

Local storm report, Oct 22, 12:55 PM CDT, 16 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 21, 8:32 PM CDT	River Flood Warning	SHV	Wood	10 days
Oct 22, 2:36 AM CDT	Areal Flood Advisory	SHV	Camp, Franklin, Smith, Titus, Upshur, Wood	3 hr
Oct 22, 5:40 AM CDT	Areal Flood Advisory	SHV	Camp, Franklin, Morris, Red River, Smith, Titus and 2 more	3 hr
Oct 22, 6:01 AM CDT	Flash Flood Warning	SHV	Camp, Franklin, Morris, Smith, Titus, Upshur and 1 more	4 hr
Oct 22, 7:30 AM CDT	Areal Flood Advisory	SHV	Bowie, Morris, Red River	4 hr
Oct 22, 7:39 AM CDT	River Flood Warning	SHV	Gregg	25 hr
Oct 22, 8:24 AM CDT	Areal Flood Advisory	SHV	Angelina, Gregg, Harrison, Nacogdoches, Panola, Rusk and 3 more	4 hr
Oct 22, 9:29 AM CDT	River Flood Warning	SHV	Angelina, Houston, Polk, Trinity, Tyler	31 days
Oct 22, 10:52 AM CDT	River Flood Warning	SHV	Gregg, Harrison, Marion, Upshur	9 days
Oct 22, 10:09 AM CDT	Areal Flood Advisory	SHV	Bossier, Caddo, De Soto, Sabine	3 hr
Oct 22, 11:13 AM CDT	Tornado Warning	SHV	De Soto, Red River	47 min
Oct 22, 11:34 AM CDT	Tornado Warning	SHV	Natchitoches, Sabine	41 min
Oct 22, 11:42 AM CDT	Areal Flood Advisory	SHV	Bienville, Claiborne, Natchitoches, Red River, Webster	4 hr
Oct 22, 12:05 PM CDT	Tornado Warning	SHV	Natchitoches	16 min
Oct 22, 12:13 PM CDT	Flash Flood Warning	SHV	Bossier	2 hr
Oct 22, 12:18 PM CDT	Tornado Warning	SHV	Natchitoches	27 min
Oct 22, 12:39 PM CDT	Flash Flood Warning	SHV	Natchitoches, Red River	111 min
Oct 22, 12:39 PM CDT	Tornado Warning	SHV	Bienville, Natchitoches, Winn	35 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 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.