...SEVERAL STORM SURVEYS HAVE BEEN COMPLETED CONCERNING STORMS

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
840 PM CDT WED APR 27 2011

...SEVERAL STORM SURVEYS HAVE BEEN COMPLETED CONCERNING STORMS
WHICH OCCURRED APRIL 25 AND APRIL 26...

THIS DAMAGE OCCURRED OVER A TWO DAY PERIOD BEGINNING MONDAY
MORNING ACROSS PORTIONS OF THE REGION...WITH MORE WIDESPREAD
DAMAGE NOTED ACROSS THE ENTIRE FOUR STATE REGION TUESDAY
AFTERNOON THROUGH TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING.

BECAUSE OF THE NUMEROUS REPORTS OF DAMAGE WITH MULTIPLE
TORNADO WARNINGS ISSUED...IT WILL TAKE SEVERAL DAYS TO BEGIN
COMPLETING THE NECESSARY STORM DAMAGE SURVEYS ACROSS THE REGION.
AS SURVEYS ARE COMPLETED...TORNADOES WILL BE PLACED IN
CHRONOLOGICAL ORDER. DAMAGE SURVEYED WHICH IS DETERMINED TO BE NON
TORNADIC WILL BE PLACED AT THE END.

1. TATUM, TX
RATING: EF1
DATE: APRIL 26 2011
TIME: 6:35 PM THROUGH 6:54 PM
MAXIMUM WIDTH: 100 YDS
INJURIES: 0
FATALITIES: 0

DETAILS:
A FEW TREES WERE SNAPPED AT THEIR BASE AND HAD LARGE LIMBS BROKEN
OFF WITH THE INITIAL TOUCHDOWN ALONG CR 2138 SOUTHWEST OF TATUM.
IT CONTINUED ALONG A NORTHEAST PATH WHERE IT DESTROYED A STORAGE
OUTBUILDING AND UPROOTED SEVERAL TREES AT THE INTERSECTION OF FM
2187 AND HWY 149. THE TORNADO CONTINUED TO THE NORTHEAST WHERE IT
UPROOTED SEVERAL TREES AND RIPPED OFF THE TOPS OF SEVERAL MORE
ALONG CR 2216 AND CR 2221. THE TORNADO CONTINUED TO THE NORTHEAST
WHERE NUMEROUS TREE DAMAGE ALONG A PARALLEL PATH WITH HENDRICKS
LAKE ROAD WAS NOTED. THE TORNADO THEN BRIEFLY CROSSED INTO PANOLA
AND HARRISON COUNTIES KNOCKING OVER A FEW TREES ALONG HWY 43,
WHERE THE TORNADO THEN LIFTED. THE PATH LENGTH WAS 13.8 MILES AND
MAXIMUM WINDS WERE ESTIMATED AT 80-85 MPH.

2. 4 MILES SSE OF MARSHALL, TX
RATING: EF2
DATE: APRIL 26 2011
TIME: 7:04 PM THROUGH 7:14 PM
MAXIMUM WIDTH: 400 YDS
INJURIES: 0
FATALITIES: 0

DETAILS:
A FEW TREES WERE SNAPPED AT THEIR BASE AND HAD LARGE LIMBS BROKEN
OFF WITH THE INITIAL TOUCHDOWN ALONG FM 2625 JUST WEST OF HWY
59. THE TORNADO PARALLELED FM 2625 CAUSING SPORADIC TREE DAMAGE
UNTIL IT REACHED THE INTERSECTION OF FM 2625 AND TAYLOR ROAD. THE
TORNADO STRENGTHENED RAPIDLY IN A SHORT TIME FRAME, CAUSING EF2
DAMAGE TO TWO RESIDENTIAL HOMES AND EF1 DAMAGE TO A THIRD. ONE
HOUSE COMPLETELY LOST ITS ROOF WHILE ANOTHER HAD AN ENTIRE ROOM
DESTROYED. THE THIRD HOME HAD ITS METAL ROOF PEELED OFF WHILE
SUSTAINING PARTIAL WALL FAILURE. NUMEROUS TREES IN THE VICINITY OF
THE HOMES WERE COMPLETELY TOPPLED OR HAD THEIR TOPS SHEARED OFF.
THE TORNADO CONTINUED TO THE NORTHEAST WHERE IT INTERSECTED
BLOCKER ROAD NEAR FM 2625 SNAPPING AND UPROOTING NUMEROUS TREES.
THE TORNADO CONTINUED TO THE NORTHEAST DISSIPATING OVER A LOGGING
ROAD A MILE TO THE EAST OF BLOCKER RD. THE PATH LENGTH WAS 5.5
MILES AND MAXIMUM WINDS WERE ESTIMATED AT 120-125 MPH.

3. JONESVILLE, TX
RATING: EF0
DATE: APRIL 26 2011
TIME: 7:24 PM THROUGH 7:34 PM
MAXIMUM WIDTH: 70 YDS
INJURIES: 0
FATALITIES: 0

DETAILS:
A FEW TREES WERE SNAPPED WITH THE INITIAL TOUCHDOWN ALONG AND JUST
NORTH I-20, NEAR THE HWY 80 EXIT JUST WEST OF WASKOM. THE TORNADO
CONTINUED NORTHEAST CAUSING SPORADIC TREE DAMAGE ALONG BELLVIEW
ROAD. THE TORNADO THEN CONTINUED NORTHEAST WHERE IT TOPPLED
SEVERAL LARGE TREES AND KNOCKED DOWN LARGE LIMBS ALONG CONCORD
ROAD BETWEEN FM 134 AND OWEN GEORGE ROAD. THE TORNADO CONTINUED
NORTHEAST WHERE IT TOOK THE TOPS OFF OF A FEW TREES ALONG OWEN
GEORGE ROAD. THE TORNADO CONTINUED NORTHEAST KNOCKING OVER A FEW
TREES ALONG FM 9, WHERE IT FINALLY DISSIPATED. THE PATH LENGTH WAS
5.94 MILES AND MAXIMUM WINDS WERE ESTIMATED AT 70-75 MPH.

4. BENTON, LA
RATING: EF0
DATE: APRIL 26 2011
TIME: 7:34 PM THROUGH 7:39 PM
MAXIMUM WIDTH: 50 YDS
INJURIES: 0
FATALITIES: 0

DETAILS:
SEVERAL LARGE TREES WERE TOPPLED AND A FEW LARGE LIMBS WERE BROKEN
OFF TREES AT THE ENTRANCE OF THE MAGNOLIA CHASE SUBDIVISION ALONG
BENTON ROAD JUST SOUTH OF THE CITY OF BENTON. THE TORNADO
CONTINUED TO THE NORTH-NORTHEAST WHERE IT BROKE OFF LARGE LIMBS ON
A FEW TREES ALONG BENTON ROAD NEAR JACOBS TRAIL. THE TORNADO
CONTINUED TO THE NORTHEAST WHERE IT SNAPPED A TREE AT ITS BASE AND
KNOCKED DOWN A FEW LARGE LIMBS ALONG PALMETTO ROAD SOUTH OF THE
CITY OF BENTON. THE TORNADO CONTINUED NORTHEAST WHERE IT TOPPLED A
LARGE TREE NEAR THE INTERSECTION OF LARKIN STREET AND PALMETTO
ROAD AND FINALLY DISSIPATED. THE PATH LENGTH WAS 3.57 MILES AND MAXIMUM
WINDS WERE ESTIMATED AT 70-75 MPH.

5. KEACHI...FRIERSON, LA
RATING: EF2
DATE: APRIL 26 2011
TIME: 7:46 PM THROUGH 8:39 PM
MAXIMUM WIDTH: 0.5 MILES
INJURIES: 2
FATALITIES: 0

DETAILS:
THE NATIONAL WEATHER SERVICE CONDUCTED A STORM SURVEY IN PANOLA COUNTY
TEXAS...DESOTO...CADDO AND BOSSIER PARISHES IN LOUISIANA AND
TRACKED A LONG TRACK TORNADO. MOST OF THE DAMAGE ALONG THE PATH
CONSISTED OF EF0 TO EF1 TYPE DAMAGE. A FEW LOCATIONS NEAR KEACHI...LONGSTREET
AND FRIERSON EXHIBITED LOW END EF2 DAMAGE. THE TORNADO WAS
CONSISTENTLY ON THE GROUND FOR A CONTINUOUS 42 MILES. TREES WERE
SNAPPED AND UPROOTED...AND AS MANY AS 3 DOZEN HOMES SUSTAINED
MINOR DAMAGE WITH A FEW MODERATELY DAMAGED HOMES WHERE CARPORTS
WERE PEELED BACK OR TREES FELL ON THEM. SEVERAL BARNS WERE KNOCKED
OVER OR DESTROYED AS WELL. THE HEAVIEST DAMAGE WAS LOCATED IN THE
COMMUNITY OF FRIERSON WHERE WIDESPREAD TREE DAMAGE OCCURRED AND
THE TORNADO WAS AT ITS WIDEST POINT. OTHER DAMAGE ALONG AND JUST
SOUTH OF THE TORNADO TRACK IS RELATED TO REAR FLANK DOWNDRAFT
OTHERWISE KNOWN AS STRAIGHT LINE WINDS. THE TORNADO TRACKED FROM
EASTERN PANOLA COUNTY NEAR FM 3359 NORTHEAST INTO DESOTO PARISH
ACROSS BELLE BOWER TEXAS LINE ROAD...STATE ROUTE 3015 WHERE TREES
WERE SNAPPED OFF 4 TO 6 FEET OFF THE GROUND AND 2 TANKS FROM A GAS
WELL WERE OVERTURNED. THE TORNADO CONTINUED NORTHEAST CROSSING
STATE ROUTE 5 BETWEEN KEACHI AND LONGSTREET?THEN CROSSED SMYRNA
ROAD KNOCKING OVER TREES ONTO AND AROUND HOMES. THE TORNADO
CROSSED HWY 171 SOUTH OF THE HWY 5 AND 171 INTERSECTION AND
FOLLOWED ALONG JESSIE LATTIN WHERE A SEVERAL HOMES WERE DAMAGED
AND BARNS DESTROYED. THE STORM CONTINUED NORTHEAST CROSSING I49
WHERE RED BLUFF ROAD CROSSES UNDER. NUMEROUS TREES WERE DOWNED AND
INCREASED IN COVERAGE AS THE STORM MOVED INTO FRIERSON. THE
TORNADO CONTINUED NORTHEAST CROSSING THE INTERSECTION OF ELLERBE
ROAD AND HWY 1 WHERE SEVERAL PECAN TREES WERE SNAPPED THEN ACROSS
THE RED RIVER INTO BOSSIER PARISH AND ACROSS ATKINS CLARK ROAD
WHERE A MOBILE TRAILER WAS FLIPPED AT A GAS WELL INJURING THE
OCCUPANTS. THE TORNADO CONTINUED NORTHEAST CROSSING HWY 154 AND
157 INTERSECTION DAMAGING TREES AND POWERLINES BEFORE WEAKENING
AND LIFTING NEAR LAKE BISTENEAU. MAXIMUM WINDS ARE ESTIMATED AT
110 - 115 MPH.

6. DUBBERLY, LA
RATING: EF1
DATE: ARPIL 26 2011
TIME: 8:54 PM THROUGH 8:57 PM
MAXIMUM WIDTH: 150 YARDS
INJURIES: 0
FATALITIES: 0

DETAILS:
THE NATIONAL WEATHER SERVICE CONDUCTED A STORM SURVEY IN WEBSTER
PARISH LA NEAR DUBBERLY AND CONCLUDED THAT DAMAGE WAS THE RESULT
OF AN EF1 TORNADO. NUMEROUS TREES WERE SNAPPED AND UPROOTED SOUTH
OF SIBLEY EAST OF 371. THE TORNADO CONTINUED NORTHEAST INTO
DUBBERLY WHERE SEVERAL HOMES SUSTAINED ROOF DAMAGE. NUMEROUS TREES
WERE SNAPPED AND UPROOTED ALONG HWY 531NORTH OF DUBBERLY. THE
TORNADO LIFTED AS IT APPROACHED INTERSTATE 20. THE STORM
RESPONSIBLE FOR THIS TORNADO IS THE SAME CELL THAT PRODUCED A 42
MILE LONG TRACK ACROSS DESOTO PARISH. MAXIMUM WINDS ARE ESTIMATED
AT 95-105 MPH.

7. HALL SUMMIT, LA
RATING: EF1
DATE: APRIL 26 2011
TIME: 10:55 PM THROUGH 10:56 PM
MAXIMUM WIDTH: 125 YARDS
INJURIES: 0
FATALITIES: 0

DETAILS:
THE NATIONAL WEATHER SERVICE CONDUCTED A STORM SURVEY IN
RED RIVER PARISH LA NEAR HALL SUMMIT AND CONCLUDED THAT DAMAGE
WAS THE RESULT OF AN EF1 TORNADO. A COUPLE BARNS WERE DESTROYED
WEST OF TOWN NORTH OF STATE ROUTE 514. THE TORNADO CONTINUED EAST
SNAPPING AND UPROOTING TREES ALONG 514. SEVERAL HOMES IN TOWN
SUSTAINED MINOR TO MODERATE ROOF DAMAGE. THE TORNADO CROSSED 514
EAST OF HALL SUMMIT WHERE NUMEROUS TREES WERE SNAPPED ONTO THE
ROAD. THE TORNADO CONTINUED EAST CROSSING 371 KNOCKING OVER A FEW
TREES BEFORE LIFTING EAST OF 371. A SHERIFF DEPUTY WITNESSED THE
TORNADO CROSSING THE HWY EAST OF HALL SUMMIT AND WAS BLOCKED IN
FROM FALLING TREES. MAXIMUM WINDS ARE ESTIMATED AT 85-90 MPH.

Public Severe Weather Outlook

ZCZC SPCPWOSPC ALL
   WOUS40 KWNS 261153
   ARZ000-LAZ000-OKZ000-TXZ000-261800-
  
   PUBLIC SEVERE WEATHER OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0653 AM CDT TUE APR 26 2011
  
   ...OUTBREAK OF SEVERE STORMS AND TORNADOES EXPECTED OVER PARTS OF
   THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY THIS EVENING AND
   OVERNIGHT...
  
   THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
   DEVELOPMENT OF A FEW STRONG LONG TRACK TORNADOES AND WIDESPREAD
   DAMAGING WIND OVER PARTS OF THE SOUTHERN PLAINS AND LOWER
   MISSISSIPPI VALLEY THIS EVENING AND OVERNIGHT.
  
   THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE
  
          SOUTHERN ARKANSAS
          EXTREME NORTHWESTERN LOUISIANA
          SOUTHEASTERN OKLAHOMA
          NORTHEASTERN TEXAS
  
   ELSEWHERE...SEVERE STORMS ARE ALSO POSSIBLE FROM...THE OHIO AND
   TENNESSEE VALLEYS THROUGH THE LOWER MISSISSIPPI VALLEY AND EASTERN
   PORTIONS OF THE SOUTHERN PLAINS.
  
   STORMS ARE EXPECTED TO REDEVELOP LATER THIS AFTERNOON AND EVENING
   GENERALLY ALONG AND NORTH OF A WARM FRONT THAT WILL MOVE TO NEAR THE
   RED RIVER AREA OF TEXAS...EASTWARD THROUGH SOUTHERN ARKANSAS AS AN
   UPPER LEVEL STORM SYSTEM APPROACHES FROM THE WEST. THE STORMS ARE
   EXPECTED TO RAPIDLY BECOME SEVERE WITH POTENTIAL FOR LONG TRACK
   STRONG TORNADOES AND LARGE HAIL. THE THREAT FOR WIDESPREAD DAMAGING
   WIND MAY ALSO INCREASE...ESPECIALLY DURING THE EVENING AND OVERNIGHT
   FROM THE LOWER MS VALLEY INTO THE TENNESSEE VALLEY.
  
   STATE AND LOCAL EMERGENCY MANAGERS ARE MONITORING THIS POTENTIALLY
   VERY DANGEROUS SITUATION. THOSE IN THE THREATENED AREA ARE URGED TO
   REVIEW SEVERE WEATHER SAFETY RULES AND TO LISTEN TO
   RADIO...TELEVISION...AND NOAA WEATHER RADIO FOR POSSIBLE
   WATCHES...WARNINGS...AND STATEMENTS LATER TODAY.
  
   ..DIAL.. 04/26/2011
  
   $$       

Hazardous Weather Outlook

000
FLUS44 KSHV 191643
HWOSHV

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SHREVEPORT LA
1143 AM CDT TUE APR 19 2011

ARZ050-051-059>061-070>073-LAZ001>006-010>012-OKZ077-TXZ096-097-
108>112-124>126-136>138-149>153-201645-
SEVIER-HOWARD-LITTLE RIVER-HEMPSTEAD-NEVADA-MILLER-LAFAYETTE-
COLUMBIA-UNION AR-CADDO-BOSSIER-WEBSTER-CLAIBORNE-LINCOLN-
UNION LA-DE SOTO-RED RIVER-BIENVILLE-MCCURTAIN-BOWIE-FRANKLIN-
TITUS-CAMP-MORRIS-CASS-WOOD-UPSHUR-MARION-SMITH-GREGG-HARRISON-
CHEROKEE-RUSK-PANOLA-NACOGDOCHES-SHELBY-
1143 AM CDT TUE APR 19 2011

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

.DAY ONE...THIS AFTERNOON AND TONIGHT...
THUNDERSTORMS WILL BE DEVELOPING LATE TODAY JUST AHEAD OF AN
APPROACHING COLD FRONT. A VERY UNSTABLE ATMOSPHERE IS FORECAST TO
BE IN PLACE ACROSS THE REGION SO STORMS WILL HAVE THE POTENTIAL TO
BECOME SEVERE...PRODUCING LARGE HAIL AND DAMAGING WINDS. IN
ADDITION...ISOLATED TORNADOES MAY BE POSSIBLE DURING THE EVENING
HOURS ESPECIALLY IN THE INTERSTATE 30 CORRIDOR OF NORTHEAST
TEXAS...SOUTHEAST OKLAHOMA AND SOUTHWEST ARKANSAS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY...
A COLD FRONT IS FORECAST TO STALL ACROSS THE REGION DURING THE DAY
WEDNESDAY PROVIDING A FOCUS FOR SCATTERED THUNDERSTORMS FOR MUCH
OF THE REST OF THE WEEK...INTO THE WEEKEND. HOWEVER...WIND SHEAR
WILL BE SOMEWHAT LIMITED...KEEPING RISK OF SEVERE WEATHER MORE
ISOLATED IN COVERAGE. HAIL AND DAMAGING WINDS WILL BE POSSIBLE WITH
ANY STORMS WHICH CAN REACH SEVERE LIMITS. WEDNESDAY APPEARS TO
HAVE THE HIGHEST RISK FOR STRONG TO SEVERE STORMS.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL LIKELY BE NEEDED LATE THIS AFTERNOON...THROUGH
MUCH OF THE OVERNIGHT HOURS.

Day One Convective Outlook

   DAY 1 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   1129 AM CDT TUE APR 19 2011
  
   VALID 191630Z - 201200Z
  
   ...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT OVER
   PARTS OF ERN OK...AR...CNTRL/SRN MO...WRN TN...KY...IL...IND AND WRN
   OH...
  
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE LOWER GREAT LAKES SWWD
   INTO SRN TX...
  
   ...OUTBREAK OF SEVERE THUNDERSTORMS CAPABLE OF WIDESPREAD
   HAIL...DAMAGING WINDS AND A FEW STRONG TORNADOES POSSIBLE THIS
   AFTERNOON THROUGH TONIGHT...
  
   ...OH VALLEY/LOWER GREAT LAKES SWWD INTO ERN OK/AR...
  
   SHORTWAVE TROUGH OBSERVED OVER THE CNTRL/SRN HIGH PLAINS THIS
   MORNING WILL CONTINUE NEWD...CONTRIBUTING TO A CORRIDOR OF 30-60 M
   HEIGHT FALLS PER 12-HR AT 500 MB FROM THE CNTRL PLAINS THROUGH THE
   MID MS VALLEY INTO UPPER GREAT LAKES.  IN THE LOW-LEVELS...SURFACE
   LOW ATTENDANT TO THIS SYSTEM ANALYZED OVER W-CNTRL MO AS OF 16Z WILL
   DEVELOP NNEWD TO N OF STL BY 19/21Z...THE IL/IND BORDER NEAR DNV BY
   20/03Z TO LAKE ERIE BY 20/12Z.  A WARM FRONT WILL PRECEDE THE
   LOW...GRADUALLY LIFTING NWD THROUGH IL/IND/OH/PA.  TRAILING COLD
   FRONT WILL ADVANCE SEWD...LIKELY EXTENDING FROM SURFACE LOW OVER
   CNTRL IL SWWD THROUGH E-CNTRL MO...NWRN AR AND SERN OK BY 20/00Z.
   THIS COLD FRONT WILL SERVE AS THE PRIMARY FOCUS FOR SEVERE
   THUNDERSTORM DEVELOPMENT THIS AFTERNOON INTO TONIGHT.
  
   12Z REGIONAL SOUNDINGS SHOWED THE PRESENCE OF STEEP MIDLEVEL LAPSE
   RATES/EML IN PLACE FROM THE CNTRL/SRN PLAINS EWD THROUGH THE
   MID/LOWER MS VALLEYS.  THESE LAPSE RATES RESIDE ABOVE A MOIST AND
   RATHER BROAD WARM SECTOR CHARACTERIZED BY PW VALUES OF 1.0-1.5
   INCHES AND BOUNDARY LAYER DEWPOINTS IN THE 60S.  ASIDE FROM ISOLATED
   OCCURRENCES OF HAIL N OF WARM FRONT OVER THE OH VALLEY TODAY...A CAP
   AT THE BASE OF THE EML IS EXPECTED TO DELAY SURFACE-BASED TSTM
   DEVELOPMENT UNTIL THIS AFTERNOON.
  
   ABUNDANT SUNSHINE...THE STEEP LAPSE RATES AND INCREASING LOW-LEVEL
   MOISTURE WILL YIELD A MODERATELY TO STRONG UNSTABLE WARM SECTOR
   TODAY WITH MLCAPE VALUES RANGING FROM 1000-2000 J/KG S OF THE WARM
   FRONT IN THE OH VALLEY...TO 3000-4000+ J/KG AHEAD OF COLD FRONT FROM
   SRN MO INTO ERN OK/WRN AR.  FRONTAL UPLIFT COUPLED WITH INCREASED
   FORCING FOR ASCENT ATTENDANT TO MIDLEVEL TROUGH ARE EXPECTED TO
   FOSTER TSTM DEVELOPMENT BY MID AFTERNOON FROM THE VICINITY OF THE
   SURFACE LOW OVER CNTRL/E-CNTRL MO SWWD TO ERN OK/WRN AR.
  
   AN ISALLOBARICALLY BACKED WIND FIELD AHEAD OF SURFACE LOW WILL
   RESULT IN A CORRIDOR OF ENHANCED LOW-LEVEL SHEAR FROM E-CNTRL MO EWD
   THROUGH CNTRL PARTS OF IL/IND.  GIVEN MORE DISCRETE STORM MODES
   /I.E. SUPERCELLS/...THIS AREA WILL REPRESENT THE GREATEST RISK FOR
   TORNADOES /SOME POSSIBLY STRONG/ FROM LATE THIS AFTERNOON INTO
   TONIGHT.  OTHERWISE...EXPECT THE DEVELOPMENT OF SUPERCELLS AND LINE
   SEGMENTS ALONG COLD FRONT WITH EVENTUAL UPSCALE GROWTH INTO ONE OR
   MULTIPLE MCSS/QLCSS.  WIDESPREAD OCCURRENCES OF HAIL AND DAMAGING
   WINDS /SOME SIGNIFICANT/ ARE EXPECTED ACROSS THE MODERATE RISK AREA
   INTO EARLY WEDNESDAY DUE TO THE PRESENCE OF STEEP LAPSE RATES AND
   THE WIDE...UNSTABLE WARM SECTOR.
  
   ...TX...
  
   TSTM POTENTIAL AND ATTENDANT SEVERE WEATHER THREAT IS MORE UNCERTAIN
   WITH SWD EXTENT ALONG THE DRYLINE THIS AFTERNOON OWING TO WEAK OR
   NEGLIGIBLE LARGE-SCALE FORCING FOR ASCENT.  NONETHELESS...MORNING
   VISIBLE SATELLITE IMAGERY DOES SUGGEST THAT STRONG DIABATIC HEATING
   WILL OCCUR TODAY ALONG AND W OF DRYLINE...BOOSTING SURFACE
   TEMPERATURES INTO THE 90S.  SHOULD SUFFICIENT HEATING/CONVERGENCE
   DEVELOP TO INITIATE ISOLATED STORMS...THE PRESENCE OF MLCAPE VALUES
   OF 3000-4000+ J/KG AND 30-40 KT OF DEEP WLY SHEAR WILL BE SUPPORTIVE
   OF SUPERCELLS CAPABLE OF LARGE HAIL.  ANY STORMS THAT MAY DEVELOP
   WOULD LIKELY WEAKEN BY LATE EVENING AS THE BOUNDARY LAYER BEGINS TO
   COOL AND CONVECTIVE INHIBITION INCREASES.

April 14, 2011 - Tornadoes

000
NOUS44 KSHV 152226
PNSSHV
ARZ050-051-059>061-070>073-LAZ001>006-010>014-017>022-OKZ077-
TXZ096-097-108>112-124>126-136>138-149>153-165>167-161030-

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
526 PM CDT FRI APR 15 2011

...STORM SURVEYS HAVE BEEN COMPLETED FOR SOUTHEASTERN OKLAHOMA
CONCERNING DAMAGE RESULTING FROM TORNADOES ON APRIL 14TH...

THE NATIONAL WEATHER SERVICE CONDUCTED A STORM SURVEY IN MCCURTAIN
COUNTY OKLAHOMA AND FOUND EVIDENCE OF AN EF0 TORNADO NEAR
SMITHVILLE. THE TORNADO FIRST TOUCHED DOWN ALONG US 259 SOUTHWEST
OF SMITHVILLE WHERE SEVERAL TREES WERE SNAPPED ON POWER LINES IN
FRONT OF A HOME. THE TORNADO CROSSED US 259 AND SNAPPED A FEW
TREES ALONG THE BANK OF MOUNTAIN FORK RIVER. NEAR THE END OF THE
TRACK...A LARGE TREE WAS SNAPPED OFF ALONG HWY 4 EAST OF
SMITHVILLE AND SEVERAL LARGE BRANCHES WERE BROKEN FROM TREES IN
THE AREA. MAXIMUM WINDS ARE ESTIMATED AT 65-70 MPH. THE TORNADO
WAS 2.5 MILES LONG AND 75 YARDS WIDE...ON THE GROUND FROM 10:33 PM CDT
THROUGH 10:36 PM CDT.

AN EF0 TORNADO WITH A PATH LENGTH OF 75 YARDS AND 4.5 MILES ALSO
OCCURRED 6 MILES SOUTHEAST OF RINGOLD. NUMEROUS TREES WERE
UPROOTED OR SNAPPED. ONE BARN WAS DESTROYED AND ONE HOME HAD MINOR
ROOF DAMAGE.

A THIRD EF0 TORNADO OCCURRED NEAR HOCHATOWN. THE TORNADO FIRST
TOUCHED DOWN ALONG MEADOW LAKE DRIVE IN BEAVER BEND STATE PARK.
SEVERAL TREES WERE UPROOTED WHILE OTHERS HAD THEIR TOPS RIPPED
OFF. THE TORNADO CONTINUED EAST CROSSING COYOTE DRIVE UPROOTING A
FEW TREES IN A CAMPING AREA. THE TORNADO FINALLY LIFTED ALONG THE
SHORELINE OF LAKE BROKEN BOW. MAXIMUM WINDS ARE ESTIMATED AT 65-70
MPH. THE TORNADO WAS 1.3 MILES LONG AND 75 YARDS WIDE...ON THE
GROUND FROM 11:37 PM CDT TO 11:38 PM CDT.

$$

PDS Tornado Watch #135

URGENT - IMMEDIATE BROADCAST REQUESTED
   TORNADO WATCH NUMBER 135
   NWS STORM PREDICTION CENTER NORMAN OK
   230 PM CDT THU APR 14 2011
  
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   TORNADO WATCH FOR PORTIONS OF
  
          MUCH OF THE EASTERN HALF OF OKLAHOMA
          PARTS OF NORTH CENTRAL/NORTHEASTERN TEXAS
  
   EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 230 PM UNTIL
   1000 PM CDT.
  
   ...THIS IS A PARTICULARLY DANGEROUS SITUATION...
  
   DESTRUCTIVE TORNADOES...LARGE HAIL TO 4 INCHES IN DIAMETER...
   THUNDERSTORM WIND GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE
   POSSIBLE IN THESE AREAS.
  
   THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE
   MILES EAST AND WEST OF A LINE FROM 15 MILES NORTH NORTHEAST OF
   BARTLESVILLE OKLAHOMA TO 40 MILES SOUTH SOUTHEAST OF SHERMAN
   TEXAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
   WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).
  
   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 134...
  
   DISCUSSION...DRY LINE LOCATED VICINITY I-35 CORRIDOR WITH THE AIR
   MASS NOW VERY UNSTABLE EWD ACROSS OK.  WITH LITTLE REMAINING
   CINH...SEVERE THUNDERSTORMS WILL DEVELOP RAPIDLY OFF THE DRY LINE
   AND MOVE THRU A VERY FAVORABLE ENVIRONMENT FOR SUPERCELLS. INITIALLY
   VERY LARGE HAIL WILL BE THE RISK GIVEN THE STEEP LAPSE RATES AND
   DEEP LAYER SHEAR.  AS THE STRONG UPPER JET MAX APPROACHES TORNADIC
   SUPERCELLS WILL BECOME MORE LIKELY BY LATER  THIS AFTERNOON/EVENING
   WITH POTENTIAL FOR LONG LIVED SUPERCELLS AND STRONG TORNADOES.  DRY
   LINE VERY LIKELY WILL MOVE LITTLE EWD FROM CURRENT POSITION WITH
   POTENTIAL FOR SEVERE STORMS DEVELOPING ON W EDGE OF WATCH INTO THE
   EVENING HOURS.
  
   AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
   SURFACE AND ALOFT TO 4 INCHES. EXTREME TURBULENCE AND SURFACE
   WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
   550. MEAN STORM MOTION VECTOR 24035

National Situation Update: Wednesday, April 13, 2011

Significant National Weather

WestA low pressure system will generate a variety of inclement weather across the Central Great Basin.  Snow showers will continue into the evening with snowfall amounts of one or two inches in the valleys.  Isolated thunderstorms are forecast across portions of Nevada with wind gusts of up to 50 mph.  Also, Critical Fire Weather conditions are forecast across southeast Arizona, southern New Mexico and west Texas throughout the day, due to low relative humidity and gusty winds.

MidwestIsolated thunderstorms are forecast from eastern Wyoming to the Great Lakes.  Tonight, an area of low pressure will move through the Central Plains bringing snow to northeast Wyoming and most South Dakota. Several inches of snow will be possible, with the heaviest snowfall over central South Dakota.
SouthUnder an area of high pressure, most of the region will remain sunny and dry.  Red Flag Warnings will remain in effect through this evening for portions of the Florida Panhandle, southern Alabama and southern Georgia, due to low relative humidity and gusty winds.
NortheastA low pressure system moving across the Southern Appalachians will produce moderate to heavy rain as it moves northeastward into New England during the early morning.  Periods of light to heavy rain will continue this evening over most .  (National Weather Service, Hydrometeorological Prediction Center, and various media sources).

Potential Dam Failure in North Dakota

On April 12, the North Dakota State Water Commission reports erosion has been observed at Burlington #1 Dam on the Des Lacs River in Ward County in north central North Dakota. This extra strain has increased the threat of a possible dam failure. There is a moderate to high risk that this dam will fail within the next 24 hours and personnel monitoring the dam were removed for safety reasons.
Based on worst case scenario simulations, if the dam was to fail, residents below the dam should expect an additional 2 to 3 foot rise in Water Level.  Residents 1 mile below the dam will experience a 1.1 foot increase above current river stage values.  This level will likely continue to the confluence between the Des Lacs and the Mouse (Souris).
Local authorities have issued an evacuation order for approximately 50 -100 residences. The ND National Guard and the Game and Fish Department have prepositioned equipment in Minot, ND in anticipation of potential response operations.  Also, the Governor has requested that Ward County be added to the Emergency Declaration (FEMA-3318-EM-ND), since the dam is owned and operated by the county.  There are no additional requests for FEMA assistance.

Midwest Spring Flooding

Major to minor flooding continues across many of the rivers in the Upper Midwest.

Earthquake Activity

On April 13, at 12:28 a.m., EDT, a 5.1 magnitude earthquake occurred 124 miles east-northeast of San Juan, PR at a depth of 19.3 miles.  No damages or injuries have been reported and no tsunami was generated.   (USGS)

Fire Activity

Tuesday, April 12, 2011

• National Preparedness Level: 1
• Initial attack activity: Moderate (324 new fires)
• New Large Fires: 7
• Large Fires Contained: 6
• Uncontained Large Fires: 19
• Type 1 IMTs Committed: 1
• Type 2 IMTs Committed: 0
• States affected: CO, NM, TX, OK, MO, GA, KS and FL (NIFC)

Wildfire Activity
Rockhouse Fire (Presido County, TX)
On April 9, a FMAG was approved for the Rockhouse Fire in Presidio County.  As of April 12, the fire had burned approximately 108,000 acres and was 60 percent contained. A Type I Incident Management Team assumed command of the fire on April 12.

Disaster Declaration Activity

No new activity Amendment No. 1 to FEMA-1961-DR-MO was approved on April 11, adding Camden County for Public Assistance.(FEMA HQ)

Day 4-8 Convective Outlook

ZCZC SPCSWOD48 ALL
   ACUS48 KWNS 070857
   SPC AC 070857
  
   DAY 4-8 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0357 AM CDT THU APR 07 2011
  
   VALID 101200Z - 151200Z
  
   ...DISCUSSION...
   07/00Z GFS IS IN AGREEMENT WITH THE LAST THREE RUNS OF THE ECMWF
   SHOWING THE STRONGER FORCING FOR ASCENT WITH THE WRN TROUGH TRACKING
   THE SRN/CENTRAL ROCKIES AND REACHING THE MID SOUTH TO WRN GREAT
   LAKES BY THE END OF DAY 4 /12Z MON APR 11/.  WHILE EACH MODEL
   MAINTAINS THE PROGRESSIVENESS OF THIS SYSTEM ON DAY 5 /MON APR
   11/...THE GFS INDICATES THE TROUGH BECOMES NEGATIVELY TILTED MOVING
   INTO THE NERN STATES.  THE ECMWF DURING THIS SAME PERIOD IS SLOWER
   WITH EWD MOVEMENT WITH A MORE NEUTRAL TO POSITIVELY-TILTED TROUGH.
   THE DIFFERENT SOLUTIONS ATTENDANT TO THIS ERN TROUGH ON DAY 5 RESULT
   IN VARYING MAGNITUDES OF AN UPSTREAM RIDGE OVER THE CENTRAL
   STATES...AND THE SUBSEQUENT EWD MOVEMENT OF A PACIFIC TROUGH FROM
   THE WEST COAST TO MS VALLEY NEXT WEEK.
  
   ...DAY 4 /SUN APR 10/...
   THE POTENTIAL FOR A REGIONAL SEVERE THREAT EXTENDING FROM NRN LA TO
   IA AND EWD THROUGH THE TN/OH VALLEYS AND PART OF THE WRN GREAT LAKES
   FROM SUNDAY AFTERNOON THROUGH SUNDAY NIGHT/EARLY MONDAY MORNING
   REMAINS VERY LIKELY.  CONFIDENCE REMAINS HIGH FOR THIS SEVERE
   WEATHER EVENT WITH THE POTENTIAL FOR DAMAGING WINDS AND TORNADOES AS
   STRONG HEIGHT FALLS SPREAD ACROSS THE DAY 4 OUTLOOK AREA...
   ESPECIALLY DURING THE LATTER HALF OF THE FORECAST PERIOD.
  
   A SURFACE LOW ATTENDANT TO THE PROGRESSIVE MID-UPPER LEVEL TROUGH IS
   EXPECTED TO TRACK FROM WRN KS INTO IA BY LATE SUNDAY AFTERNOON AND
   REACH THE WRN GREAT LAKES BY 12Z MONDAY.  A TRAILING COLD FRONT IS
   EXPECTED TO OVERTAKE THE PLAINS DRY LINE WITH TSTMS DEVELOPING
   INITIALLY FROM ERN OK TO WRN IA.  SLY LOW LEVEL WINDS WILL MAINTAIN
   A MOIST AIR MASS ALREADY IN PLACE AT THE START OF DAY 4 AND SUPPORT
   A MODERATELY UNSTABLE WARM SECTOR.  STRENGTHENING DEEP LAYER WIND
   FIELDS ACROSS THE UNSTABLE AIR MASS WILL PROMOTE BOTH LINE SEGMENTS
   AND SUPERCELLS WITH THE INITIAL ACTIVITY SPREADING TO THE MS VALLEY.
   FOR SUNDAY NIGHT...THE SEVERE WEATHER THREAT SHOULD EVOLVE TO
   PRIMARILY DAMAGING WINDS AS A BROAD SWLY LLJ /50-70 KT/ DEVELOPS
   FROM THE MID SOUTH TO OH VALLEY AND A SQUALL LINE ADVANCES EWD FROM
   THE MS VALLEY.
  
   ...DAY 5 /MON APR 11/...
   GIVEN MODEL DIFFERENCES IN THE TIMING AND ORIENTATION OF THE DAY 4
   TROUGH AS IT MOVES EWD ON DAY 5 AND UNCERTAINTY IN THE DEGREE OF
   DESTABILIZATION WITH EWD EXTENT...A REGIONAL SEVERE WEATHER THREAT
   AREA WILL NOT BE INCLUDED FOR THIS PERIOD.
  
   ...BEYOND DAY 5...
   MODEL UNCERTAINTIES WITH THE TIMING OF A PACIFIC TROUGH REACHING THE
   PLAINS STATES NEXT WEEK PRECLUDES THE INCLUSION OF ANY THREAT AREAS
   FOR DAYS 7-8 /WED APR 13 THROUGH THU APR 14/.
  
   ..PETERS.. 04/07/2011

4-5 Apr Severe Outbreak

The most recent outbreak of severe weather over the eastern US was one of the larger ones on record.  The featured map presents the time composite maximum base reflectivity of NEXRAD along with the tornado and severe thunderstorm warnings issued.  The deep south is nearly completely covered with both.  The main severe weather mode was damaging winds and a number of tornadoes were reported as well.  There are 733 warnings shown on this map!

Bill Smith, K1ARK, Receives National Recognition for Storm Spotting Activities

It is difficult to imagine the number of hours that Dr Bill Smith, K1ARK, of Fayetteville, Arkansas, logs in his job as the University of Arkansas’ Director of New Media for the Razorback Athletics Department. Smith spends countless hours blogging, filming, commentating and handling the social media responsibilities for 19 teams and the department, but he still finds time to assist Washington County residents when dangerous weather conditions arise. Smith has volunteered for the Washington County Department of Emergency Management for more than a decade, assisting with county weather emergency communications. In addition, Smith is the volunteer Public Information Officer for the DEM with Advanced P10 certification from FEMA.

For these efforts, Smith -- an ARRL member -- has been named the Bob Kenworthy Community Service Award winner by the College of Sports Information Directors of America (CoSIDA). The Bob Kenworthy Community Service Award is presented annually to a member for civic involvement and accomplishments outside of the sports information office. CoSIDA is a 2700-plus member national organization comprised of the sports public relations, communications and information professionals throughout all levels of collegiate athletics in the United States and Canada. Smith will be honored at the CoSIDA at the organization’s annual convention in June.
“Bill has helped as the district emergency coordinator on Amateur Radio services countless times as a volunteer,” said John Luther, Director of 911, Fire Services and Search and Rescue. “Any time there is a severe weather warning, Bill has activated the storm spotter severe weather net, coordinating a network of Amateur Radio operators to verify weather in their areas. Through this operation, the National Weather Service in Tulsa can match up computer models and data with what is actually taking place in real time. In addition, Bill has assisted our offices in creating press releases during severe weather events and he has provided 24 hour operation during our Amateur Radio field day. He does wonderful work and is very professional. Bill has invested countless hours behind the scenes. He is very unselfish and his efforts are appreciated.”

Smith has become an integral part of SKYWARN, a long-standing program that fosters close working relationships between local communities and the National Weather Service. The program seeks to provide the public with the best information during periods of hazardous weather. On the local level, he created and managed the W5YM University WeatherNet as Washington County’s contribution to the regional SKYWARN system.

A certified OK-FIRST radar operator, Smith assists the county by training volunteers and coordinating those efforts during threatening weather in the Northwest Arkansas area. He has managed the Tulsa National Weather Services’ annual SKYWARN training; for eight years, he has served as the liaison for the county to the Tulsa Weather Forecast Office. In addition, Smith wrote the policies and procedures for local severe weather operations, and developed a training book for storm spotters.
“As one of the members of our office said to the group at this year’s training event in Fayetteville, ‘If we hear a report of severe weather that has come through Bill’s group, we are starting to type out a warning.’ That is a testament to the hard work and dedication Bill puts forth,” said NWS Tulsa Meteorologist-in-Charge Steven Pilz.

Pilz documented two of Smith’s contributions. Both examples came as Smith’s life as a Razorback crossed paths with his involvement of storm tracking. The first occurred during the 2009 NCAA Men’s and Women’s Outdoor Track and Field Championships in Fayetteville, when the media received a public report of a tornado. Smith -- who was already working the event as the Razorbacks’ Director of New Media -- began a rapid coordination between officials in Fayetteville and meteorologists in Tulsa to help assess that the report from the neighboring country was a hoax. Because of Smith’s local spotters, many unnecessary protective actions were averted for both Washington County and the track meet.

Pilz also recounted that a powerful storm moved through Northwest Arkansas in 2006. Smith coordinated with meteorologists in area and with University of Arkansas officials in suspending a Razorback soccer match against Kentucky, due to a threat of lightning. The information Smith provided was proven correct when a person was struck and killed by lightning on a lake nearby the Razorback Soccer Stadium at approximately the same time his warning to clear the fields was made.
Smith has more than 25 years in the field of media relations and new media. The former Associate A

Athletic Director of Women’s Communications at Arkansas, Smith has earned 14 Best in the Nation and an additional 37 national and 42 district publications awards from CoSIDA. Recognition of his skill and success has continued in his role as Director of New Media. He has earned and shared numerous Communicator Awards for video and new media video production.  -- Thanks to the University of Arkansas and the College of Sports Information Directors of America for the information

Convective Outlooks

Day 1 (Today)

...SRN PLAINS/WRN OZARKS...
   MOISTENING OF THE AIRMASS ACROSS THE SRN PLAINS WILL CONTINUE TODAY
   AS THE SRN END OF A WELL-DEFINED LOW-LEVEL JET MOVES EWD ACROSS THE
   REGION. MODERATE INSTABILITY IS FORECAST BY MID TO LATE AFTERNOON
   FROM CNTRL AND NORTH TX EXTENDING NWD INTO CNTRL AND ERN OK WHERE
   FORECAST SOUNDINGS SHOW MLCAPE VALUES AROUND 2500 J/KG. IN SPITE OF
   THE INSTABILITY...A CAPPING INVERSION WILL LIKELY REMAIN IN PLACE
   FOR MUCH OF THE AFTERNOON AND EVENING SUPPRESSING CONVECTIVE
   DEVELOPMENT. SEVERAL MODEL FORECASTS INITIATE STORMS IN NE OK AND NW
   AR DURING THE LATE EVENING WITH STORMS EXPANDING SWWD ALONG A COLD
   FRONT DURING THE OVERNIGHT PERIOD. THE MODERATE INSTABILITY...STEEP
   MID-LEVEL LAPSE RATES AND STRONG DEEP LAYER SHEAR SHOULD BE
   SUFFICIENT FOR A LARGE HAIL AND WIND DAMAGE THREAT. AFTER
   MIDNIGHT...ISOLATED THUNDERSTORM DEVELOPMENT COULD OCCUR SWWD ACROSS
   CNTRL AND NORTH TX AS THE COLD FRONT MOVES INTO THE REGION FROM THE
   NORTHWEST. FORECAST SOUNDINGS IN CNTRL AND NORTH TX AT 09Z TO 12Z
   SUGGEST DEEP LAYER SHEAR MAY BE STRONG ENOUGH FOR A MARGINAL WIND
   DAMAGE AND HAIL THREAT.


Day 2 (Monday)

THE 02/12Z ECMWF IS CONSISTENT WITH ITS 02/00Z RUN...AND REMAINS THE
   SLOWEST AND FARTHEST SOUTH OF THE OPERATIONAL AND LATEST 21Z SREF
   500 MB MEAN HEIGHTS...SHOWING THE BASAL SHORTWAVE TROUGH MOVING INTO
   THE LOWER MS VALLEY DURING THE LATTER HALF OF DAY 2.  HOWEVER...EVEN
   WITH THE SLOWER ECMWF SOLUTION...60-100 METER HEIGHT FALLS ARE
   EXPECTED IN ADVANCE OF THE PROGRESSIVE FULL LATITUDE TROUGH FROM THE
   OH VALLEY TO MID SOUTH/LOWER MS VALLEY SUPPORTING STRONG DEEP LAYER
   SSWLY WIND FIELDS.  THE 03/00Z GFS COMPARED TO THIS MODEL RUN FROM
   02/00Z IS NOW INDICATING STRONGER FORCING FOR ASCENT INTO THE MID
   SOUTH BY MONDAY AFTERNOON.
  
   IN THE LOW LEVELS...THE LATEST GFS CONTINUES TO INDICATE STRONGER
   DEEPENING OF THE SURFACE LOW...WITH BOTH THE 00Z GFS/12Z ECMWF
   TRACKING THE LOW FROM THE CENTRAL GREAT LAKES TO QUEBEC.  EACH MODEL
   CONTINUES TO SHOW STRONG BAROCLINICITY AS A COLD FRONT ADVANCES EWD
   ACROSS THE OH/TN AND LOWER MS VALLEYS AND CENTRAL GULF COAST STATES.
    THE ECMWF REMAINS THE SLOWER MODEL WITH EWD PROGRESSION OF THE COLD
   FRONT...AND IN AGREEMENT WITH HPC MODEL DIAGNOSTICS HAVE KEPT SERN
   EXTENT OF THE SLIGHT RISK IN LINE WITH THE ECMWF TIMING OF THE COLD
   FRONT INTO GA BY 12Z TUESDAY.
  
   ...E TX TO CENTRAL GULF COAST STATES NWD TO TN/OH VALLEYS...
   GREATEST SEVERE WEATHER THREAT AREA /COVERAGE AND INTENSITY/...
   INCLUDING POTENTIAL FOR TORNADOES...DAMAGING WINDS AND HAIL IS
   EXPECTED TO BE ACROSS THE LOWER MS/TN VALLEYS.
  
   DESPITE THE MODEL DIFFERENCES DISCUSSED IN THE SYNOPSIS...EVEN 60-90
   METER HEIGHT FALLS PER ECMWF FROM THE OH VALLEY TO THE MID
   SOUTH/LOWER MS VALLEY AND MID-UPPER LEVEL TROUGH BECOMING NEUTRALLY
   ORIENTED WILL SUPPORT FORCING FOR ASCENT SPREADING EWD ATOP THE COLD
   FRONT AND ADJACENT WARM SECTOR.  STEEP MIDLEVEL LAPSE RATES /8-9 C
   PER KM/ ACROSS THE SLIGHT RISK AREA AT 12Z MONDAY WILL INITIALLY CAP
   THE AIR MASS.  HOWEVER...THE HEIGHT FALLS ARE EXPECTED TO ELIMINATE
   THE CAP EARLY IN THE PERIOD /MONDAY MORNING/.  FORCING ATTENDANT TO
   THE TROUGH SHOULD MAINTAIN ONGOING TSTMS ALONG THE FRONT WHICH WILL
   EXTEND FROM LOWER MI SWWD TO NERN AND CENTRAL TX...WHILE NEW STORMS
   WILL ALSO DEVELOP AS THE CAP WEAKENS FROM W-E MONDAY MORNING INTO
   THE AFTERNOON.
  
   SLY LOW LEVEL WINDS WILL SPREAD MOISTURE NWD IN ADVANCE OF THE COLD
   FRONT...WITH SURFACE DEWPOINTS IN THE LOWER 60S SPREADING ACROSS THE
   OH VALLEY...AND MID-UPPER 60S SWD FROM TN.  VALUES AROUND 70 SHOULD
   BE ALONG THE GULF COAST.  THIS MOISTURE COMBINED WITH RELATIVELY
   STEEP MIDLEVEL LAPSE RATES SHOULD RESULT IN MODERATE INSTABILITY
   FROM E TX TO CENTRAL GULF COAST STATES AND INTO PARTS OF THE TN
   VALLEY.  INCREASING DEEP LAYER SHEAR VECTORS BECOMING LESS PARALLEL
   TO THE COLD FRONT ACROSS THIS REGION SUGGESTS SUPERCELLS WILL BE
   MORE LIKELY.  GIVEN THE STRENGTH OF THE LOW LEVEL SHEAR...TORNADOES
   WILL BE POSSIBLE IN ADDITION TO DAMAGING WINDS AND HAIL /SOME VERY
   LARGE/.  SEVERE WEATHER THREAT SHOULD PERSIST ACROSS THE CENTRAL
   GULF COAST STATES MONDAY NIGHT AS THE COLD FRONT SPREADS EWD INTO A
   MODERATELY UNSTABLE AND STRONGLY SHEARED ENVIRONMENT.
  
   FARTHER N INTO THE OH VALLEY INSTABILITY WILL BE WEAKER.  HOWEVER...
   FORCING FOR ASCENT WITH THE UPPER TROUGH AND POSSIBLY ASSOCIATED
   WITH A LEAD IMPULSE WILL SUPPORT TSTM DEVELOPMENT AS THE COLD FRONT
   ADVANCES EWD.  BULK SHEAR VECTORS ORIENTED MORE PARALLEL TO THE
   FRONT SUGGEST A LINEAR MODE WITH THE STRENGTH OF LOW LEVEL WINDS
   /50-60 KT/ SUGGEST DAMAGING WINDS WILL BE THE PRIMARY THREAT.

Hazardous Weather Outlook

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SHREVEPORT LA
605 AM CDT SUN APR 3 2011

ARZ050-051-059>061-070>073-LAZ001>006-010>014-017>022-OKZ077-TXZ096-
097-108>112-124>126-136>138-149>153-165>167-031700-
ANGELINA-BIENVILLE-BOSSIER-BOWIE-CADDO-CALDWELL-CAMP-CASS-CHEROKEE-
CLAIBORNE-COLUMBIA-DE SOTO-FRANKLIN-GRANT-GREGG-HARRISON-HEMPSTEAD-
HOWARD-JACKSON-LA SALLE-LAFAYETTE-LINCOLN-LITTLE RIVER-MARION-
MCCURTAIN-MILLER-MORRIS-NACOGDOCHES-NATCHITOCHES-NEVADA-OUACHITA-
PANOLA-RED RIVER LA-RED RIVER TX-RUSK-SABINE LA-SABINE TX-
SAN AUGUSTINE-SEVIER-SHELBY-SMITH-TITUS-UNION AR-UNION LA-UPSHUR-
WEBSTER-WINN-WOOD-
605 AM CDT SUN APR 3 2011

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

.DAY ONE...TODAY AND TONIGHT...

A COLD FRONT WILL BE APPROACHING EXTREME SOUTHEAST OKLAHOMA AND THE
IMMEDIATE ADJACENT SECTIONS OF NORTHEAST TEXAS AND SOUTHWEST ARKANSAS
BETWEEN 4 AM TO 7 AM CDT MONDAY. SHOWERS AND THUNDERSTORMS WILL BE
DEVELOPING AHEAD OF AND ALONG THE BOUNDARY...WITH SOME OF THE
STORMS HAVING THE POTENTIAL TO PRODUCE LARGE HAIL AND HIGH AND
DAMAGING WINDS.

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

A COLD FRONT WILL CONTINUE TO MOVE ACROSS THE FOUR STATE REGION ON
MONDAY WITH A BAND OF SHOWERS AND STRONG TO SEVERE THUNDERSTORMS
ALONG AND AHEAD OF THE FRONTAL BOUNDARY. THE BOUNDARY WILL BE
EXITING OFF TO THE EAST AND SOUTHEAST OUT OF THE FORECAST AREA BY
LATE MONDAY AFTERNOON AND EARLY EVENING...ENDING THE RAIN CHANCES
AND SEVERE WEATHER. STRONG DYNAMICS AND INSTABILITY WILL BE IN PLACE
AS THESE STORMS DEVELOP...WITH THE POTENTIAL FOR LARGE HAIL...
DAMAGING WINDS...ISOLATED TORNADOES...AND LOCALLY HEAVY RAINFALL.
A PASSING UPPER DISTURBANCES WILL PROVIDE FOR RETURNING RAIN
CHANCES DURING THE LATE WEEK AND MIDDLE OF NEXT WEEKEND...BUT
NOT AS STRONG AS THIS EARLY WEEK SYSTEM.

.SPOTTER INFORMATION STATEMENT...

THE ACTIVATION OF STORM SPOTTER NETWORKS...HAM RADIO OPERATORS...AND
EMERGENCY MANAGEMENT PERSONNEL...MAY BE NEEDED FOR LATE
TONIGHT AND INTO THE DAY MONDAY.

DAY 4-8 CONVECTIVE OUTLOOK

...DISCUSSION...
   00Z GFS/ECMWF REMAIN SIMILAR IN MAINTAINING AN AMPLIFIED FULL
   LATITUDE TROUGH MOVING EWD ACROSS THE PLAINS AND MS/LOWER OH VALLEYS
   ON DAY 4 /MON/...AND THEN ACROSS THE ERN STATES ON DAY 5 /TUE/ AS A
   MORE NEGATIVELY-TILTED SYSTEM.  THESE MODELS DO DIFFER IN THE TIMING
   OF THIS TROUGH WITH THE ECMWF FASTER...ESPECIALLY ON DAY 5
   ACCELERATING THIS TROUGH OFF THE ERN SEABOARD BY 12Z WEDNESDAY. 
  
   ...DAY 4 /MON APR 4/...
   MODELS MAINTAIN LIKELIHOOD FOR WIDESPREAD SEVERE STORMS FROM THE
   MID-LOWER MS VALLEY INTO THE OH/TN VALLEYS AND CENTRAL GULF COAST
   STATES ON DAY 4.  GULF MOISTURE WILL ADVECT NWD ACROSS THIS REGION
   IN ASSOCIATION WITH VERY STRONG EWD MIGRATING SLY LLJ.  TSTM
   ACTIVITY WILL BE SUPPORTED AS FORCING FOR DEEP ASCENT ATTENDING THE
   UPPER TROUGH SHIFTS EAST OF STRONGER EML.  THIS AND STRONG WIND
   FIELDS WILL SUPPORT A THREAT FOR SUPERCELLS AND LINE SEGMENTS
   WITH TORNADOES...LARGE HAIL AND DAMAGING WINDS.