Historic Multi Day Tornado/Flooding Event 4/23-28/2011

[GCANE]

The Vilonia tornado looked like a BEAST. Awful awful news for the town.

At today looks like it's gonna be another really dangerous day, too. Fort Worth/Dallas just at the edge of the HIGH/MDT area as well.

I think DFW may be under the gun today.

[GRAYSONCO.WX]

What are the thoughts for the Sherman, Denison area, 65 miles NNE of Dallas?

[GCANE]

Looks like skies clearing out to the north and west of DFW.

Should see a good break in the cap mid afternoon today with about 4500 CAPE.

This could be explosive.

[GCANE]

What are the thoughts for the Sherman, Denison area, 65 miles NNE of Dallas?

Could be bad.

If I were chasing, it would be a good spot to set up.

[GRAYSONCO.WX]

What are the thoughts for the Sherman, Denison area, 65 miles NNE of Dallas?

Could be bad.

If I were chasing, it would be a good spot to set up.

Thank you for the information!
Around what time do you think the storms will start to form?

[CrazyC83]

SPC AC 261234

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0734 AM CDT TUE APR 26 2011

VALID 261300Z - 271200Z

...THERE IS A HIGH RISK OF SVR TSTMS LATE THIS AFTERNOON INTO
TONIGHT FOR NE TX...FAR SE OK...EXTREME NW LA...AND THE SRN HALF OF
AR...

...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK...FROM
NE TX/SE OK TO THE CONFLUENCE OF THE MS/OH RIVERS...

...THERE IS A SLGT RISK OF SVR TSTMS IN A BROAD SWATH FROM THE SRN
PLAINS EWD/NEWD TO THE MS/OH VALLEYS AND THE LOWER GREAT LAKES...

...DANGEROUS TORNADO AND SEVERE THUNDERSTORM OUTBREAK EXPECTED LATE
THIS AFTERNOON INTO TONIGHT FROM NE TX ENEWD TO THE MS RIVER...

...SYNOPSIS...
AN INITIAL SHORTWAVE TROUGH OVER MO/IL WILL EJECT NEWD TOWARD LOWER
MI TODAY...WHILE AN INTENSE UPSTREAM JET STREAK PROGRESSES ESEWD TO
THE SRN PLAINS BY TONIGHT. MORNING SUBSIDENCE OVER AR /IN THE WAKE
OF THE DEPARTING WAVE/ WILL BE REPLACED BY ASCENT BEGINNING ALONG
THE RED RIVER VALLEY OF N TX/SRN OK LATER THIS AFTERNOON...SPREADING
EWD THIS EVENING INTO SE OK/NE TX AND SRN AR OVERNIGHT. A STRONG
SURFACE CYCLONE WILL DEVELOP EWD ALONG THIS SAME CORRIDOR IN
RESPONSE TO STRONG UPPER DIVERGENCE IN THE LEFT EXIT REGION OF THE
90-100 KT MIDLEVEL JET. THE CYCLOGENESIS WILL ALSO PROMOTE THE
DEVELOPMENT OF A STRENGTHENING SLY/SSWLY LLJ FROM THE ARKLATEX TO
THE LOWER MS VALLEY OVERNIGHT. MEANWHILE...RICH BOUNDARY LAYER
MOISTURE ACROSS E TX...BENEATH A PLUME OF STEEP MIDLEVEL LAPSE RATES
ORIGINATING TO THE W...WILL PROVIDE MODERATE-STRONG WARM SECTOR
INSTABILITY IN ADVANCE OF THE DEVELOPING CYCLONE. THE NET RESULT
WILL BE A STRONGLY SHEARED AND UNSTABLE WARM SECTOR LATE THIS
AFTERNOON INTO TONIGHT...WHICH APPEARS SUPPORTIVE OF A DANGEROUS
TORNADO AND SEVERE THUNDERSTORM OUTBREAK.

...S/SE AR INTO NW MS TODAY...
INITIAL WARM ADVECTION STORMS WILL FORM DURING THE DAY ALONG AND N
OF THE OUTFLOW/WARM FRONT ACROSS S/SE AR AND NW MS...AS LOW-LEVEL
WAA INCREASES WITH A DEVELOPING LLJ. A FEW SUPERCELLS ARE EXPECTED
ALONG THE WARM FRONT...WHERE MODERATE INSTABILITY AND EFFECTIVE SRH
AOA 200 M2/S2 WILL BE SUPPORTIVE OF A FEW TORNADOES...IN ADDITION TO
LARGE HAIL AND DAMAGING WINDS.

...ARKLATEX/SE OK LATE THIS AFTERNOON INTO EARLY TONIGHT...
OVERNIGHT CONVECTION THAT MOVED OVER AR/NW MS LEFT AN E-W OUTFLOW
BOUNDARY THAT WILL BECOME THE EFFECTIVE WARM FRONT TODAY. FARTHER
S...A WEAKENING MCS OVER SRN LA/MS HAS GENERATED A COLD POOL ACROSS
CENTRAL LA/E TX...BUT AN UNIMPEDED FEED OF LOW 70S BOUNDARY LAYER
DEWPOINTS REMAINS TO THE W OF THIS CONVECTION ACROSS SE TX. THE SE
TX MOISTURE WILL SURGE NWD TODAY AS THE SRN LA STORMS
DISSIPATE...WHILE STEEP MIDLEVEL LAPSE RATES WILL CONTINUE TO
OVERSPREAD THE WARM SECTOR FROM THE W. THESE PROCESSES...COMBINED
WITH DAYTIME HEATING...WILL CONTRIBUTE TO AFTERNOON MLCAPE VALUES OF
2500-3500 J/KG IN THE NE TX WARM SECTOR...WITH SOMEWHAT LESSER
INSTABILITY FARTHER E ACROSS NRN LA/SRN AR...AND FARTHER N INTO SE
OK.

SUPERCELLS ARE EXPECTED TO INITIATE BY MID-LATE AFTERNOON ACROSS
N/NE TX...ALONG THE WARM FRONT AND DRYLINE TO THE IMMEDIATE E/SE OF
THE SURFACE LOW...AND SPREAD EWD TOWARD SW AR/NW LA THROUGH TONIGHT.
THE STRONG INSTABILITY...EFFECTIVE BULK SHEAR IN EXCESS OF 60
KT...EFFECTIVE SRH OF 300-500 M2/S2...AND A SUFFICIENTLY MOIST
BOUNDARY LAYER WILL BE FAVORABLE FOR LONG-TRACK/DAMAGING TORNADOES
WITH DISCRETE AND CLUSTER SUPERCELLS INTO THE LATE EVENING/EARLY
NIGHTTIME HOURS. VERY LARGE HAIL AND DAMAGING WINDS WILL ALSO BE
LIKELY WITH THE INITIAL SUPERCELLS.

...NRN LA/SE AR/NW MS/WRN TN TONIGHT...
AS THE STRONG SYNOPTIC CYCLONE PROGRESSES EWD AND INTERACTS WITH THE
UNSTABLE WARM SECTOR...INTENSE CONVECTION IS LIKELY THROUGH THE
OVERNIGHT HOURS. INITIAL TORNADIC SUPERCELLS IN NE TX/SW AR AREA
SHOULD EVENTUALLY GROW UPSCALE INTO ONE OR MORE INTENSE
MCS/S...WHICH COULD EVOLVE INTO BOW ECHOES WITH THE POTENTIAL FOR
WIDESPREAD/INTENSE DAMAGING WINDS...AS WELL AS TORNADOES. THIS
ACTIVITY SHOULD PROGRESS QUICKLY EWD/NEWD TO THE MS RIVER LATE
TONIGHT AS THE SYNOPTIC WAVE BEGINS TO EJECT ENEWD.

...OH VALLEY REGION THROUGH EARLY TONIGHT...
THE EJECTING LEAD SHORTWAVE TROUGH WILL PROVIDE A BROAD SWATH OF
MODERATE-STRONG SWLY MIDLEVEL FLOW...ABOVE RESIDUAL BOUNDARY LAYER
DEWPOINTS IN THE UPPER 50S TO LOWER 60S. THE LINGERING CLOUDS AND
RESIDUAL OUTFLOW FROM PRIOR CONVECTION MAKE THE CONVECTIVE EVOLUTION
SOMEWHAT UNCERTAIN TODAY ACROSS THE OH VALLEY REGION...THOUGH
SURFACE-BASED INSTABILITY WILL BE SUFFICIENT FOR A FEW SUPERCELLS
AND/OR BOWING SEGMENTS WITH A RISK FOR A COUPLE OF
TORNADOES...DAMAGING WINDS...AND ISOLATED LARGE HAIL.

..THOMPSON/COHEN.. 04/26/2011

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
CURRENT UTC TIME: 1412Z (10:12AM), RELOAD THIS PAGE TO UPDATE THE TIME

[CrazyC83]

SPC AC 260600

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT TUE APR 26 2011

VALID 271200Z - 281200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS A LARGE PORTION OF
KENTUCKY AND TENNESSEE...NORTHEAST AND EAST CENTRAL
MISSISSIPPI...THE NORTHERN HALF OF ALABAMA...AND NORTHWEST
GEORGIA...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE LOWER GREAT LAKES
REGION SWWD TO THE CENTRAL GULF COAST...

...SYNOPSIS...
A LARGE UPPER TROUGH INITIALLY OVER THE CENTRAL U.S. IS FORECAST TO
MAKE SLOW BUT STEADY EWD PROGRESS THIS PERIOD...WITH A POTENT SPEED
MAX FORECAST TO ROUND THE BASE OF THE TROUGH AND SHIFT ACROSS THE
MID SOUTH INTO THE OH VALLEY REGION WITH TIME.

AT THE SURFACE...A DEEPENING LOW IS FORECAST TO SHIFT FROM THE
VICINITY OF AR EARLY NNEWD TO THE GREAT LAKES REGION...WHILE A
TRAILING COLD FRONT ACCELERATES EWD ACROSS THE OH/TN/MID AND LOWER
MS VALLEYS. BY THE END OF THE PERIOD...THE FRONT SHOULD CROSS THE
APPALACHIANS -- WITH A ZONE BETWEEN THE MS RIVER AND THE APPALACHIAN
CREST LIKELY TO SEE A WIDESPREAD/POTENTIALLY DANGEROUS SEVERE
WEATHER EVENT THIS PERIOD.

...LOWER GREAT LAKES REGION SWWD TO THE CENTRAL GULF COAST...
***POTENTIAL FOR A SIGNIFICANT/WIDESPREAD SEVERE WEATHER EVENT --
INCLUDING THE POSSIBILITY OF A TORNADO OUTBREAK -- REMAINS EVIDENT
THIS FORECAST...CENTERED ON THE MID SOUTH/TN VALLEY AREA.***

SOME QUESTIONS EXIST ATTM WITH RESPECT TO CONVECTIVE EVOLUTION THIS
PERIOD...CENTERED AROUND THE ONGOING STORMS PROGGED TO BE SHIFTING
ACROSS ERN AR AND INTO WRN TN/NRN MS AT THE START OF THE PERIOD.
WHILE THE COVERAGE AND PROGRESSION OF THIS CONVECTION COULD HAVE
EFFECTS ON TIMING/LOCATION OF LATER DAY STORMS AS WELL AS THE
QUALITY OF AIRMASS IN SOME AREAS...IT APPEARS ATTM THAT EARLY STORMS
SHOULD CONTINUE ENEWD ACROSS WRN KY/WRN TN/NRN MS THROUGH THE
MORNING...POSSIBLY WEAKENING SOME WITH TIME.

HOWEVER...AS HEATING OF THE MOIST BOUNDARY LAYER COMMENCES AHEAD OF
THE ADVANCING FRONT AND ASSOCIATED UPPER FEATURE AND AWAY FROM ANY
CONVECTIVELY-COOLED AREAS...STORM REINTENSIFICATION AND NEW STORM
DEVELOPMENT WILL BE LIKELY BY EARLY AFTERNOON.

STRONG SLY SURFACE FLOW AHEAD OF THE FRONT INCREASING TO 80 TO 100
KT FROM THE SW AT MID LEVELS WILL PROVIDE SHEAR HIGHLY FAVORABLE FOR
VERY INTENSE/LONG-LIVED ROTATING UPDRAFTS. THIS -- COMBINED WITH
FAVORABLE THERMODYNAMIC ENVIRONMENT...APPEARS SUPPORTIVE OF
SIGNIFICANT LONG-TRACK TORNADOES AND -- DEPENDING UPON STORM MODE --
THE THREAT FOR WIDESPREAD/VERY DAMAGING WINDS ALONG WITH LARGE HAIL.
ATTM...GREATEST POTENTIAL FOR TORNADOES APPEARS TO EXIST ACROSS
TN/KY/NRN MS AND NRN AND CENTRAL AL...WHILE POTENTIAL FOR WIDESPREAD
WIND DAMAGE -- ALONG WITH TORNADO THREAT -- WILL EXTEND NNEWD ACROSS
THE OH VALLEY TOWARD THE LOWER GREAT LAKES REGION AHEAD OF THE
FRONT.

OVERNIGHT...SOME TORNADO POTENTIAL WILL CONTINUE...THOUGH STORMS MAY
BECOME MORE LINEAR AHEAD OF THE ACCELERATING FRONT AS IT MOVES TO --
AND POSSIBLY ACROSS -- THE APPALACHIANS. EXPECT POTENTIAL FOR
DAMAGING WINDS TO PERSIST WITH THE CONVECTIVE LINE...GIVEN THE
OVERALL STRENGTH OF THE LARGE-SCALE SYSTEM.

..GOSS.. 04/26/2011

CLICK TO GET WUUS02 PTSDY2 PRODUCT

NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
CURRENT UTC TIME: 1426Z (10:26AM), RELOAD THIS PAGE TO UPDATE THE TIME

[srainhoutx]

If the HRRR is correct, what a frightening evening ahead for NE TX and AR. Stay safe folks and keep informed.

[GCANE]

What are the thoughts for the Sherman, Denison area, 65 miles NNE of Dallas?

Thank you for the information!
Around what time do you think the storms will start to form?

Last couple runs of HRRR have had intermittent data.

Looking at RUC, it looks like initiation will be around 20Z.

[CrazyC83]

There could be many Vilonia-like tornadoes today. Hope everyone has somewhere to go!

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

$$

[GRAYSONCO.WX]

Last couple runs of HRRR have had intermittent data.

Looking at RUC, it looks like initiation will be around 20Z.[/quote][/quote][/quote]

What is the HRRR showing for my area? Pretty bad storms?

[CrazyC83]

Shreveport is REALLY concerned.

000
FLUS44 KSHV 261024
HWOSHV

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SHREVEPORT LA
524 AM CDT TUE APR 26 2011

ARZ050-051-059>061-070>073-LAZ001>006-010>014-OKZ077-TXZ096-097-
108>112-124>126-136>138-149>151-261800-
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-
524 AM CDT TUE APR 26 2011

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...TODAY AND TONIGHT...

...FLASH FLOOD WATCH IN EFFECT FOR THE NORTHERN THIRD OF NORTHEAST
TEXAS...MCCURTAIN COUNTY IN SOUTHEAST OKLAHOMA AS WELL AS ALL OF
SOUTHWEST AND SOUTH CENTRAL ARKANSAS THROUGH 7 AM WEDNESDAY...

THE POTENTIAL EXIST FOR A VIOLENT OUTBREAK OF TORNADOES LATE THIS
AFTERNOON INTO THE OVERNIGHT HOURS ALONG AND NORTH OF THE
INTERSTATE 20 CORRIDOR OF NORTHEAST TEXAS AND NORTHERN
LOUISIANA...INCLUDING SOUTHEAST OKLAHOMA AND ALL OF SOUTHERN
ARKANSAS.

AN AREA OF LOW PRESSURE WILL QUICKLY SHIFT EASTWARD FROM THE TEXAS
HILL COUNTRY...TO NEAR THE MIDDLE RED RIVER VALLEY OF NORTHEAST
TEXAS INTO SOUTHEAST OKLAHOMA LATE TODAY. A DRYLINE WILL EXTEND
SOUTH OF THE AREA OF LOW PRESSURE ACROSS NORTHEAST TEXAS WHILE A
WARM FRONT WILL TAKE UP A POSITION ALONG THE RED RIVER OF
SOUTHEAST OKLAHOMA AND NORTHEAST TEXAS...TO NEAR THE
LOUISIANA...ARKANSAS BORDER. A STRONG UPPER LEVEL TROUGH TO OUR
WEST...IN COMBINATION WITH A VERY UNSTABLE AND HIGHLY SHEARED
ENVIRONMENT WILL LIKELY RESULT IN THE FORMATION OF SUPERCELLS
ACROSS THE REGION WITH A VIOLENT AND POTENTIAL DEADLY TORNADO
OUTBREAK EXPECTED. VERY LARGE HAIL AND DAMAGING BOWING LINE
SEGMENTS WILL ALSO ACCOMPANY THE CONVECTION LATE THIS AFTERNOON
THROUGH THE OVERNIGHT HOURS.

VERY HEAVY RAINFALL WAS OBSERVED ACROSS THE NORTHERN THIRD OF
NORTHEAST TEXAS...SOUTHEAST OKLAHOMA AND SOUTHWEST ARKANSAS ON
MONDAY. AN ADDITIONAL TWO TO FOUR INCHES OF RAIN WITH ISOLATED
HIGHER AMOUNTS CAN BE EXPECTED ACROSS THIS REGION LATE TODAY
THROUGH TONIGHT WHICH WILL LIKELY RESULT IN ADDITIONAL FLASH
FLOODING CONCERNS.

A STRONG COLD FRONT WILL PUSH THROUGH THE REGION WEDNESDAY MORNING
WITH THE THUNDERSTORM ACTIVITY ENDING FROM WEST TO EAST.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY...
STRONG TO SEVERE THUNDERSTORMS WILL AGAIN BE POSSIBLE ACROSS THE
REGION THIS WEEKEND WITH THE APPROACH OF ANOTHER UPPER LEVEL STORM
SYSTEM.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL BE NEEDED AS EARLY AS THIS AFTERNOON BUT
ESPECIALLY THIS EVENING AND THROUGH THE OVERNIGHT HOURS FOR THIS
SIGNIFICANT SEVERE THUNDERSTORM THREAT.

$$

LAZ017>022-TXZ152-153-165>167-261800-
SABINE LA-NATCHITOCHES-WINN-GRANT-CALDWELL-LA SALLE-NACOGDOCHES-
SHELBY-ANGELINA-SAN AUGUSTINE-SABINE TX-
524 AM CDT TUE APR 26 2011

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

.DAY ONE...TODAY AND TONIGHT...
SHOWERS AND THUNDERSTORMS WILL ONCE AGAIN BE POSSIBLE LATE THIS
AFTERNOON THROUGH THE OVERNIGHT HOURS ACROSS THE REGION. WITH A
VERY UNSTABLE ENVIRONMENT IN PLACE...STRONG TO SEVERE
THUNDERSTORMS ARE POSSIBLE...SOME OF WHICH COULD PRODUCE TORNADOES
WITH HAIL AND DAMAGING STRAIGHT LINE WINDS. THIS THREAT WILL
REALLY INCREASE AS WE TRANSITION INTO THE OVERNIGHT HOURS TONIGHT
AHEAD OF A STRONG COLD FRONT.

THE FRONT WILL PUSH THROUGH THE REGION WEDNESDAY MORNING WITH THE
THUNDERSTORM ACTIVITY ENDING FROM WEST TO EAST.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY...
STRONG TO SEVERE THUNDERSTORMS WILL AGAIN BE POSSIBLE ACROSS THE
REGION THIS WEEKEND WITH THE APPROACH OF ANOTHER UPPER LEVEL STORM
SYSTEM.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED AS EARLY AS THIS AFTERNOON BUT
ESPECIALLY THIS EVENING AND THROUGH THE OVERNIGHT HOURS FOR THE
POTENTIAL OUTBREAK OF SEVERE THUNDERSTORMS.

$$

13

[Bunkertor]

Looking at the SHV Sounding, i´d be concerned either.

[CrazyC83]

High Risk being expanded to include the Memphis area.

MESOSCALE DISCUSSION 0585
NWS STORM PREDICTION CENTER NORMAN OK
1051 AM CDT TUE APR 26 2011

AREAS AFFECTED...FAR EASTERN AR/SOUTHWEST TN/NORTHERN MS

CONCERNING...OUTLOOK UPGRADE

VALID 261551Z - 261645Z

THE EXISTING CATEGORICAL HIGH RISK WILL LIKELY BE EXPANDED
NORTHEASTWARD IN THE FORTHCOMING 1630Z DAY 1 OUTLOOK TO INCLUDE
REMAINING PORTIONS OF EASTERN AR...WHILE ADDING PARTS OF SOUTHWEST
TN/NORTHWEST MS INTO A HIGH RISK. FOR ADDITIONAL METEOROLOGICAL
DISCUSSION...SEE THE FORTHCOMING DAY 1 OUTLOOK THAT WILL BE ISSUED
BY AROUND 1630Z.

..GUYER.. 04/26/2011

[brunota2003]

Not good...they are expecting more rain tonight (up to a half inch):

CIVIL EMERGENCY MESSAGE
RELAYED BY NATIONAL WEATHER SERVICE TULSA OK
634 AM CDT TUE APR 26 2011

THE FOLLOWING MESSAGE IS TRANSMITTED AT THE REQUEST OF
THE CARROLL COUNTY ARKANSAS EMERGENCY MANAGEMENT.

BEAVER DAM GATES WILL BE OPEN TO 7 FEET. AN ADDITIONAL 1 TO 2 FEET
RISE IN THE FLOOD WATER CAN BE EXPECTED DOWNSTREAM. THIS LEVEL OF
RISE MAY SPREAD WATER INTO HOMES ALONG THE RIVER DOWNSTREAM OF THE
DAM. MANY ROADWAYS REMAIN IMPASSABLE AND WILL REMAIN SO WITH THE
ADDITIONAL WATER RELEASE. RESIDENTS IN LOW LYING AREAS NEAR AND
ALONG THE RIVER...INCLUDING THE COMMUNITIES OF BEAVER AND HOLIDAY
ISLAND...ARE URGED TO EVACUATE AND SEEK HIGHER GROUND.

[CrazyC83]

60H wind added as well.

SPC AC 261627

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1127 AM CDT TUE APR 26 2011

VALID 261630Z - 271200Z

...THERE IS A HIGH RISK OF SVR TSTMS LATE THIS AFTERNOON INTO
TONIGHT FOR NE TX...FAR SE OK...EXTREME NW LA...THE SRN HALF OF
AR...SOUTHWEST TN...AND NORTHWEST MS...

...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK...FROM
NE TX/SE OK TO THE CONFLUENCE OF THE MS/OH RIVERS...

...THERE IS A SLGT RISK OF SVR TSTMS FROM SRN OK/EAST TX INTO MUCH
OF THE LOWER/MID MS VALLEY...TN AND OH VALLEYS...AND INTO PA/NY...

...AN OUTBREAK OF SEVERE THUNDERSTORMS INCLUDING STRONG TORNADOES
AND WIDESPREAD DAMAGING WINDS IS FORECAST TO OCCUR LATER TODAY AND
TONIGHT...

MORNING WATER VAPOR LOOPS SHOW A BROAD UPPER TROUGH OVER MUCH OF THE
UNITED STATES...WITH TWO SIGNIFICANT SHORTWAVE FEATURES TRACKING
ACROSS THE NATION. THE FIRST TROUGH IS CURRENTLY OVER THE MID MS
AND OH VALLEY AND WILL EJECT NORTHEASTWARD TODAY INTO THE NORTHEAST
STATES. THIS WILL LEAD TO A RELATIVELY LARGE AREA OF POTENTIAL FOR
ISOLATED SEVERE THUNDERSTORMS AS FAR NORTHEAST AS PORTIONS OF NY/PA.
ANOTHER SHORTWAVE TROUGH IS OVER CO/NM AND WILL QUICKLY TRANSLATE
INTO OK/TX BY EVENING. THIS FEATURE IS EXPECTED TO RESULT IN
SIGNIFICANT SEVERE WEATHER OVER THE ARKLATEX AND LOWER/MID MS
VALLEY.

...OK/TX INTO THE LOWER/MID MS VALLEY...
LOW LEVEL MOISTURE IS RAPIDLY RETURNING NORTHWARD THIS MORNING
ACROSS THIS REGION...WITH MID/UPPER 60S DEWPOINTS NOW AS FAR NORTH
AS SOUTHERN AR. THE 12Z FWD RAOB SHOWED A PRONOUNCED CAPPING
INVERSION...WHICH SHOULD INHIBIT STRONG CONVECTIVE DEVELOPMENT UNTIL
MID AFTERNOON. BY THAT TIME...STRONG DAYTIME HEATING AND CONTINUED
MOISTENING OF THE BOUNDARY LAYER WILL YIELD MLCAPE VALUES OF
3000-4000 J/KG AND A WEAKENED CAP OVER NORTHEAST TX/NORTHWEST
LA/SOUTHWEST AR. ISOLATED DISCRETE SUPERCELL THUNDERSTORMS ARE
EXPECTED TO FORM IN THIS REGION...WHICH SHOULD TRACK NORTHEASTWARD
ACROSS SOUTHERN AR/NORTHERN LA DURING THE EVENING. LOW LEVEL WINDS
WILL BE STRENGTHENING DURING THIS PERIOD AS SURFACE CYCLOGENESIS
OCCURS OVER TX...LEADING TO INCREASINGLY FAVORABLE SHEAR PROFILES
FOR TORNADIC ACTIVITY.

MOST MODEL SOLUTIONS SUGGEST A SECOND ROUND OF INTENSE SUPERCELLS
DEVELOP NEAR THE DRYLINE ACROSS NORTH TX AND SOUTHEAST OK BY EARLY
EVENING. THESE STORMS WILL ALSO TRACK EAST-NORTHEASTWARD INTO AR/LA
/ROUGHLY THE SAME AXIS AS THE FIRST WAVE OF STORMS/ AND WILL BE IN A
MUCH MORE FAVORABLE VERTICAL SHEAR PROFILE FOR RISKS OF
STRONG/DAMAGING TORNADOES.

TONIGHT...VERY STRONG LOW LEVEL WINDS ARE FORECAST TO DEVELOP OVER
EASTERN AR/NORTHWEST MS/WEST TN NORTHWARD INTO IL/IND. THERE IS
CONSIDERABLE UNCERTAINTY REGARDING THE EVOLUTION OF STORMS AS THEY
PROGRESS INTO THIS ENVIRONMENT. THE STORMS MAY REMAIN DISCRETE
ACROSS AR WITH A RISK OF STRONG/VIOLENT TORNADOES...OR THEY MAY GROW
UPSCALE INTO A FAST-MOVING BOW ECHO WITH THE RISK OF WIDESPREAD
SIGNIFICANT WIND DAMAGE AND ISOLATED TORNADOES. IN EITHER
CASE...CONDITIONS ARE CLEARLY FAVORABLE A HIGH-END SEVERE WEATHER
EVENT WELL INTO THE NIGHT. FOR THESE REASONS...HAVE EXTENDED THE
HIGH RISK FARTHER EAST.

...TN/OH VALLEY INTO THE NORTHEAST STATES...
THE LEAD SHORTWAVE TROUGH EXTENDS FROM IL/IND INTO MS/AL. A BAND OF
THUNDERSTORMS ASSOCIATED WITH THIS TROUGH HAS BEEN SLOWLY
DIMINISHING THIS MORNING...BUT IS LIKELY TO REJUVENATE BY EARLY
AFTERNOON. WIDESPREAD STRONG MID LEVEL WINDS AND MODERATE CAPE WILL
LEAD TO A RISK OF HAIL AND LOCALLY DAMAGING WINDS OVER A RELATIVELY
BROAD AREA FROM AL/GA NORTHEASTWARD INTO PA/NY. DETAILS ON SPECIFIC
AREAS OF THIS THREAT WILL BE ADDRESSED THROUGH THE DAY IN
FORTHCOMING MESOSCALE DISCUSSIONS.

..HART/GRAMS.. 04/26/2011

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
CURRENT UTC TIME: 1635Z (12:35PM), RELOAD THIS PAGE TO UPDATE THE TIME

[brunota2003]

I'd take an 80 or 90 mph gust over an EF3 or EF4 long tracked tornado any day. That's the difference between roof damage and house leveled.

[CrazyC83]

I'd take an 80 or 90 mph gust over an EF3 or EF4 long tracked tornado any day. That's the difference between roof damage and house leveled.

True, but the 90 mph wind gusts affect a much larger area than the tornadoes. In the case of Memphis, even if an EF5 tornado were to hit downtown, most of the suburbs would feel like nothing happened. With 100 mph winds, the entire metropolitan area is brought to its knees for a while.

[CrazyC83]

ZCZC SPCPWOSPC ALL
WOUS40 KWNS 261637
ARZ000-LAZ000-MSZ000-OKZ000-TNZ000-TXZ000-270200-

PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1137 AM CDT TUE APR 26 2011

...AN OUTBREAK OF SEVERE THUNDERSTORMS EXPECTED OVER PARTS OF THE
SOUTHERN PLAINS AND LOWER/MIDDLE MISSISSIPPI RIVER VALLEY LATE THIS
AFTERNOON AND TONIGHT...

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
DEVELOPMENT OF A FEW STRONG/LONG-TRACK TORNADOES AND WIDESPREAD
DAMAGING WINDS OVER PARTS OF THE SOUTHERN PLAINS AND LOWER/MIDDLE
MISSISSIPPI RIVER VALLEY LATE THIS AFTERNOON AND TONIGHT.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE

SOUTHERN HALF OF ARKANSAS
FAR NORTHWEST LOUISIANA
NORTHWEST MISSISSIPPI
FAR SOUTHEAST OKLAHOMA
SOUTHWEST TENNESSEE
NORTHEAST TEXAS

ELSEWHERE...SURROUNDING THE HIGH RISK AREA...SEVERE STORMS ARE ALSO
POSSIBLE FROM PORTIONS OF THE SOUTHERN PLAINS NORTHEASTWARD TO THE
OHIO VALLEY...LOWER GREAT LAKES REGION...AND APPALACHIANS.

AS AN UPPER STORM SYSTEM APPROACHES FROM THE SOUTHWEST UNITED
STATES...THUNDERSTORMS ARE EXPECTED TO DEVELOP BY LATE THIS
AFTERNOON AND EVENING ACROSS PORTIONS OF THE SOUTHERN PLAINS AND
ARKLATEX REGION. WITH A MOIST AND UNSTABLE AIR MASS IN PLACE...THE
STORMS ARE EXPECTED TO RAPIDLY BECOME SEVERE WITH THE POTENTIAL FOR
LONG-TRACK STRONG TORNADOES AND LARGE HAIL. THIS WILL ESPECIALLY BE
THE CASE ACROSS PORTIONS OF NORTHEAST TEXAS...FAR SOUTHERN
OKLAHOMA...FAR NORTHERN LOUISIANA...AS WELL AS MUCH OF ARKANSAS.
ADDITIONALLY...THE THREAT FOR SIGNIFICANT AND WIDESPREAD WIND DAMAGE
WILL ALSO INCREASE LATER TONIGHT...ESPECIALLY DURING THE LATE
EVENING AND OVERNIGHT HOURS ACROSS THE LOWER/MIDDLE MISSISSIPPI
VALLEY INTO THE TENNESSEE VALLEY.

INTO WEDNESDAY...A WIDESPREAD SEVERE WEATHER OUTBREAK...INCLUDING
STRONG TORNADOES...WILL AGAIN BE POSSIBLE. AT THIS TIME...IT APPEARS
THE GREATEST THREAT WILL EXIST ACROSS THE TENNESSEE VALLEY...OHIO
VALLEY...AND SURROUNDING PORTIONS OF THE SOUTHEASTERN U.S.

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.

..GUYER.. 04/26/2011

$$

[CrazyC83]

Will we see only the second ever Day 2 High Risk at 1730Z?