Alert archive / Texas / Flash Flood Watches in 2015

Flash Flood Watch 9, NWS Shreveport, LA

May 17, 201521 counties in Texas; 17 parishes in Louisiana; 9 counties in Arkansas

NWS Shreveport, LA issued this flash flood watch at May 17, 2015, 4:22 PM CDT for 21 counties in Texas; 17 parishes in Louisiana; 9 counties in Arkansas. It took effect at May 17, 2015, 10:00 PM CDT. It was in force for 18 hr.

The area

The counties it named.

The facts

Issued
May 17, 2015, 4:22 PM CDT (21:22 UTC)
In effect from
May 17, 2015, 10:00 PM CDT
Expired
May 18, 2015, 3:56 PM CDT
In force
18 hr
Issued by
NWS Shreveport, LA
Flood severity
None
All 47 counties

Columbia County, AR, Hempstead County, AR, Howard County, AR, Lafayette County, AR, Little River County, AR, Miller County, AR, Nevada County, AR, Sevier County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, Winn Parish, LA, Angelina County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Franklin County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Nacogdoches County, TX, Panola County, TX, Red River County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Smith County, TX, Titus County, TX, Upshur County, TX, Wood County, TX

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 9.4 hours before the alert went out and 282 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, Lake Charles Mun, LA at 12:00Z on 2015-05-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2562 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, Lake Charles Mun, LA at 12:00Z on 2015-05-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 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
2562 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
613 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
125 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 flash flood watch 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 flash flood watch went out at May 17, 1:01 PM CDT, 3 hours 21 minutes earlier.

Area forecast discussion, May 17, 1:01 PM CDT, 3 hours 21 minutes before
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Hazardous weather outlook, May 17, 12:11 PM CDT, 4 hours 11 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SHREVEPORT LA
1211 PM CDT SUN MAY 17 2015

ARZ050-051-059>061-070>073-LAZ001>004-OKZ077-TXZ096-097-108>112-
124>126-136>138-149>151-181100-
SEVIER-HOWARD-LITTLE RIVER-HEMPSTEAD-NEVADA-MILLER-LAFAYETTE-
COLUMBIA-UNION-CADDO-BOSSIER-WEBSTER-CLAIBORNE-MCCURTAIN-
RED RIVER-BOWIE-FRANKLIN-TITUS-CAMP-MORRIS-CASS-WOOD-UPSHUR-
MARION-SMITH-GREGG-HARRISON-CHEROKEE-RUSK-PANOLA-
1211 PM CDT SUN MAY 17 2015

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

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

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
SPREAD EAST OUT OF EAST TEXAS...SOUTHEAST OKLAHOMA...AND SOUTHWEST
ARKANSAS BY EARLY TO MID AFTERNOON. HOWEVER...BRIEF HEAVY RAINFALL
AND LOCALLY GUSTY WINDS WILL BE POSSIBLE WITH THE STRONGER STORMS.
ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
REDEVELOP LATE TONIGHT OVER NORTHEAST TEXAS...SOUTHEAST
OKLAHOMA...SOUTHWEST ARKANSAS AND NORTHWEST LOUISIANA...AHEAD OF
ANOTHER UPPER LEVEL DISTURBANCE THAT WILL MOVE NORTHEAST OVER THE
REGION. LOCALLY HEAVY RAINFALL AND THE THREAT FOR FLASH FLOODING
WILL AGAIN EXIST LATE TONIGHT...WITH ADDITIONAL RAINFALL AMOUNTS
OF ONE TO THREE INCHES POSSIBLE OVER ALREADY SATURATED GROUNDS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY...

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL BE ONGOING
MONDAY MORNING ACROSS THE REGION...GRADUALLY SHIFTING EAST BY
AFTERNOON. THE HEAVY RAINFALL AND FLASH FLOOD THREAT WILL CONTINUE
THROUGH THAT TIME BEFORE DIMINISHING DURING THE AFTERNOON.
ADDITIONAL ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
BE POSSIBLE TUESDAY THROUGH SATURDAY...AS A COUPLE OF WEAK SURFACE
FRONTS BACKDOOR THEIR WAY INTO THE REGION AND BECOME STATIONARY.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF EMERGENCY MANAGERS...SKYWARN NETWORKS...AND AMATEUR
RADIO OPERATORS...MAY BE NEEDED TONIGHT FOR HEAVY RAINFALL AND
FLASH FLOOD REPORTS.

LAZ005-006-010>014-017>022-TXZ152-153-165>167-181100-
LINCOLN-UNION-DE SOTO-RED RIVER-BIENVILLE-JACKSON-OUACHITA-SABINE-
NATCHITOCHES-WINN-GRANT-CALDWELL-LA SALLE-NACOGDOCHES-SHELBY-
ANGELINA-SAN AUGUSTINE-
1211 PM CDT SUN MAY 17 2015

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 THUNDERSTORMS WILL BE POSSIBLE THIS
AFTERNOON AND EVENING OVER DEEP EAST TEXAS AND NORTHCENTRAL
LOUISIANA...AS A DECAYING COMPLEX OF THUNDERSTORMS OVER EAST TEXAS
AND NORTHWEST LOUISIANA MOVE INTO A VERY MOIST AND UNSTABLE AIR
MASS. ISOLATED STRONG STORMS CAPABLE OF PRODUCING DAMAGING WINDS
AND BRIEF HEAVY RAINFALL WILL BE POSSIBLE BEFORE DIMINISHING LATE
IN THE DAY. ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO REDEVELOP LATE TONIGHT OVER EAST TEXAS...SOUTHWEST
ARKANSAS AND NORTHWEST LOUISIANA...AND MAY MOVE INTO THE AREA BY
DAYBREAK MONDAY.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY...

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS SHOULD BE ONGOING
ACROSS THE AREA MONDAY...AND SHOULD GRADUALLY SPREAD EAST
SOUTHEAST OVER THE REGION...DIMINISHING BY LATE AFTERNOON. LOCALLY
HEAVY RAINFALL AND ISOLATED STRONG STORMS CAPABLE OF PRODUCING
DAMAGING WINDS WILL BE POSSIBLE MONDAY BEFORE THE STORMS EXIT THE
REGION. ADDITIONAL ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
BE POSSIBLE TUESDAY THROUGH SATURDAY...AS A COUPLE OF WEAK SURFACE
FRONTS BACKDOOR THEIR WAY INTO THE REGION AND BECOME STATIONARY.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF EMERGENCY MANAGERS...SKYWARN NETWORKS...AND AMATEUR
RADIO OPERATORS...MAY BE NEEDED THIS AFTERNOON AND EVENING FOR
ISOLATED SEVERE THUNDERSTORM REPORTS.

15

In the hours before

Special weather statement, May 17, 2:39 PM CDT, 1 hour 43 minutes before
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Special weather statement, May 17, 3:06 PM CDT, 1 hour 16 minutes before
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Special weather statement, May 17, 3:36 PM CDT, 46 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
May 17, 5:32 AM CDTFlash Flood WarningSHVBowie, Franklin, Morris, Red River, Titus3 hr
May 17, 8:29 AM CDTAreal Flood AdvisorySHVBowie, Camp, Franklin, Morris, Red River, Titus and 1 more3 hr
May 17, 11:31 AM CDTRiver Flood WarningSHVFranklin, Morris, Red River, Titus20 days
May 17, 11:31 AM CDTRiver Flood WarningSHVWood5 days
May 17, 11:32 AM CDTRiver Flood WarningSHVFranklin, Morris, Titus15 days
May 17, 2:46 PM CDTRiver Flood WarningSHVNacogdoches, Rusk, San Augustine, Shelby21 days
May 17, 2:39 PM CDTSpecial Weather StatementSHVJackson, Winn66 min
May 17, 3:06 PM CDTSpecial Weather StatementSHVCaldwell54 min
May 17, 3:36 PM CDTSpecial Weather StatementSHVOuachita54 min
May 17, 5:08 AM CDTSpecial Weather StatementSHVSevier67 min

Nearby

Flash Flood Watches in Texas, 2015Flash Flood Watches in Louisiana, 2015Flash Flood Watches in Arkansas, 2015Every flash flood watch in 2015

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.