Severe Weather Discussion - October '09

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DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0329 AM CDT MON OCT 26 2009

VALID 291200Z - 031200Z

...DISCUSSION...

LATEST MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT REGARDING THE
SPEED/MOVEMENT OF UPPER LOW EJECTING FROM THE CNTRL/SRN ROCKIES NEWD
INTO THE GREAT LAKES/OH VALLEY REGION DURING THE DAY4-5 TIME FRAME.
BOTH THE GFS AND ECMWF SUGGEST STRONG MID LEVEL FLOW WILL TRANSLATE
THROUGH THE BASE OF THE TROUGH INTO THE MS VALLEY WHERE DEEPENING OF
THIS LOW PRESSURE SYSTEM WILL BE NOTED THROUGH A DEEP LAYER. WITH
MOISTURE/INSTABILITY EXPECTED TO RETURN ACROSS THE SCNTRL
U.S...THUNDERSTORMS SHOULD READILY DEVELOP ALONG ADVANCING COLD
FRONT ACROSS OK/TX DAY4...THEN SHIFT EWD INTO THE MS VALLEY DAY5
WHERE FRONTAL INTENSIFICATION IS EXPECTED. IF SUFFICIENT
INSTABILITY CAN RETURN TO IL/IND ORGANIZED SEVERE THUNDERSTORMS WILL
LIKELY OCCUR AS INTENSE HEIGHT FALLS/FORCING WILL BE NOTED ACROSS
THIS REGION.

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DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1231 AM CDT TUE OCT 27 2009

VALID 281200Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS NWRN TX AND SWRN OK...

...TX/OK...

00Z MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT WITH EVOLUTION OF
LONG WAVE TROUGH OVER THE WRN U.S. INTO THE DAY2 PERIOD. STRONGEST
JET CORE WINDS WILL ROUND THE BASE OF THE SWRN U.S. TROUGH OVER NRN
MEXICO BEFORE EJECTING NEWD ACROSS THE TRANS PECOS REGION INTO THE
TX PANHANDLE LATE. THIS WILL INDUCE LEE CYCLOGENESIS OVER NERN NM
EARLY BEFORE SFC LOW IS DISPLACED INTO SWRN KS DURING THE OVERNIGHT
HOURS. LEADING EDGE OF MARITIME AIRMASS OVER THE WRN GULF SHOULD
RETURN IN EARNEST BEGINNING AROUND 28/12Z...WITH 60+ SFC DEW POINTS
EXPECTED TO SURGE INTO PORTIONS OF NWRN TX BY 00Z. IT APPEARS A
REASONABLE AMOUNT OF BOUNDARY LAYER HEATING WILL BE NOTED NEAR THE
LEE TROUGH...PRIOR TO FRONTAL MERGER...ACROSS THE TX SOUTH PLAINS
INTO THE TRANS PECOS REGION. THOUGH LOW LEVEL LAPSE RATES WILL
STEEPEN SIGNIFICANTLY REMOVING EARLY INHIBITION...IT APPEARS
MOISTURE WILL BE DELAYED SUCH THAT DIURNAL CONVECTION WILL STRUGGLE
TO DEVELOP. WHAT SEEMS MORE LIKELY WILL BE FOR THUNDERSTORM
DEVELOPMENT DURING THE OVERNIGHT PERIOD AS CONTINUED MOISTENING
WITHIN THE BOUNDARY LAYER CONTRIBUTES TO AN EVER-INCREASING...ALBEIT
SOMEWHAT MARGINAL...AXIS OF INSTABILITY AHEAD OF SHARPENING COLD
FRONT. WITH MID 60S DEW POINTS EXPECTED TO SPREAD INTO SWRN OK
THERE WILL LIKELY BE SUFFICIENT THERMAL ADJUSTMENT/BUOYANCY FOR
SFC-BASED CONVECTION ALONG/AHEAD OF COLD FRONT BETWEEN 03-06Z ACROSS
NWRN TX INTO THE ERN TX PANHANDLE. FORECAST SHEAR PROFILES ARE VERY
INTENSE WITH SFC-6KM VALUES ON THE ORDER OF 70-75KT WITH STRONG
VEERING PROFILES AND 50KT+ FLOW JUST OFF THE SFC. ANY STORMS THAT
DEVELOP ALONG COLD FRONT...IF SUFFICIENTLY BUOYANT...COULD POSE A
DAMAGING WIND THREAT. LATEST THINKING IS A SQUALL LINE SHOULD
EMERGE ALONG COLD FRONT FROM THE ERN OK/TX PANHANDLE...SWD INTO NWRN
TX BEFORE SPREADING EAST INTO WRN OK/NCNTRL TX BY SUNRISE. IN
ADDITION...GIVEN THE STRONG DEEP LAYER SHEAR AND LOW LEVEL
HELICITY...A FEW TORNADOES CAN NOT BE RULED OUT...ESPECIALLY IF
DISCRETE SUPERCELLS DEVELOP.



DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0214 AM CDT TUE OCT 27 2009

VALID 291200Z - 301200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM CNTRL TX TO SRN MO...

...CNTRL TX...NEWD TO SRN MO...

UPPER TROUGH OVER THE SRN/CNTRL ROCKIES IS EXPECTED TO SHIFT EAST
INTO THE PLAINS DURING THE DAY3 PERIOD...THOUGH NOT AS A UNIFIED
LONG WAVE TROUGH BUT RATHER IN SEVERAL PIECES. ONE
SIGNIFICANT...AND LIKELY PRIMARY...UPPER CIRCULATION CENTER WILL
EJECT NEWD ACROSS CO INTO SD WITH SOME VARIANCE NOTED AMONG THE
LATEST SHORT RANGE MODEL GUIDANCE. A SECONDARY PIECE OF ENERGY WILL
EMERGE OVER FAR WEST TX LATE WITHIN THE BASE OF THE LONGER WAVE.
THIS SECONDARY SHORTWAVE WILL TRY TO INDUCE A WAVE ALONG SRN
PORTIONS OF THE COLD FRONT...MOST LIKELY ALONG THE LOWER RIO GRANDE
VALLEY BEFORE SHIFTING OFFSHORE. GIVEN THE BI-MODAL STRUCTURE OF
THIS EJECTING SYSTEM THERE ARE SOME NUANCES THAT WILL BE IMPOSSIBLE
TO ASCERTAIN THREE DAYS IN ADVANCE...NAMELY CONVECTIVE INFLUENCES
FROM DAY2 ACTIVITY AND ULTIMATE STORM MODE. OF PARTICULAR CONCERN
IS THE OVERALL MOISTURE INCREASE EXPECTED AHEAD OF COLD FRONT.
MODELS ARE IN GENERAL AGREEMENT THAT A LARGE SWATH OF 60+ SFC DEW
POINTS...70+ ACROSS PARTS OF TX/LA...WILL BE OBSERVED ACROSS THE
WARM SECTOR WHERE STRONGER H5 FLOW WILL OVERSPREAD A
MARGINAL-MODESTLY UNSTABLE AIRMASS. GIVEN THAT DEEP LAYER SHEAR IS
FORECAST TO BE STRONG...ANY STORMS THAT MANAGE TO DEVELOP EITHER
ALONG THE COLD FRONT...OR PERHAPS IMMEDIATELY AHEAD OF WIND
SHIFT...COULD PRODUCE SEVERE DAMAGING WIND GUSTS OR PERHAPS EVEN
ISOLATED TORNADOES. NWD EXTENT OF SEVERE RISK WILL BE LIMITED BY
MOISTURE RETURN NEEDED FOR SFC-BASED BUOYANCY.

..DARROW.. 10/27/2009

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DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1214 PM CDT TUE OCT 27 2009

VALID 281200Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE SRN
PLAINS...

...SYNOPSIS...
MID-WEEK ATTENTION WILL BE ON THE VERY STRONG UPR JET THAT WILL
CARVE OUT A COLD UPR LOW OVER THE INTERMOUNTAIN W. THIS FEATURE
WILL SETTLE INTO THE FOUR CORNERS REGION EARLY ON WEDNESDAY BEFORE
EJECTING ENE TO THE CNTRL HIGH PLAINS WEDNESDAY NIGHT.

IN THE LOWER-LEVELS...A FRONT THAT SETTLES INTO THE NRN GULF BASIN
IN WAKE OF THE CURRENT IMPULSE MIGRATING NEWD FROM THE MID-SOUTH IS
EXPECTED TO REDEVELOP QUICKLY N INTO PARTS OF NRN TX AND LWR MS VLY
BY WEDNESDAY NIGHT. UPSTREAM...LEE CYCLOGENESIS WILL TAKE PLACE
OVER NERN NM WEDNESDAY AFTN WITH THE LOW DEVELOPING INTO SWRN KS BY
12Z THURSDAY. SRN PLAINS LEE TROUGH WILL EVENTUALLY BE OVERTAKEN BY
A CDFNT LATE WEDNESDAY NIGHT OVER WRN TX WITH THE FRONT ARRIVING
OVER PARTS OF OK/CNTRL TX BY SUNRISE THURSDAY.

...SRN PLAINS...
BOUNDARY LAYER MOISTURE WILL BEGIN TO RETURN IN EARNEST WEDNESDAY
AFTN/NIGHT ACROSS THE SRN PLAINS AS SLY FLOW INCREASES DOWNSTREAM
FROM THE APCHG UPR LOW. SFC DEW POINTS IN EXCESS OF 60 DEG F WILL
BE SURGING INTO PARTS OF CNTRL/NWRN TX BY WEDNESDAY EVENING...BUT
PERHAPS SUFFICIENTLY DELAYED TO REDUCE THE RISK OF DIURNAL TSTM
DEVELOPMENT ALONG THE LEE TROUGH. MORE LIKELY SCENARIO WILL BE FOR
POST-SUNSET TSTMS TO EVOLVE ALONG THE TX/OK BORDER SWD INTO THE
TRANSPECOS REGION AS PRE-FRONTAL AIR MASS CONTINUES TO MOISTEN AND
LARGE-SCALE HEIGHT FALLS SPREAD EWD.

FORECAST DEEP LAYER SHEAR PROFILES WILL BE QUITE STRONG AND DESPITE
THE POST-DIURNAL CYCLE TIMING...INITIAL STORMS MAY BE SUPERCELLS
WITH LARGE HAIL...DMGG WINDS AND PERHAPS A TORNADO OR TWO. BACKING
LOW/MID-LVL WIND FIELDS WITH TIME AND INCREASING ASCENT WILL RESULT
IN AN EXPANDING SQUALL LINE FROM WRN/CNTRL OK INTO CNTRL TX BY 12Z
THURSDAY. WHILE SVR THREAT WILL TRANSITION INTO MOSTLY DMGG
WINDS...ISOLD TORNADOES CANNOT BE RULED OUT...PARTICULARLY WHERE
STORMS CAN REMAIN DISCRETE THE LONGEST WITHIN THE MORE ROBUST
BOUNDARY LAYER MOISTURE ACROSS CNTRL/NRN TX.

...UPR TX CST/E TX/WRN LA...
STREAMER SHOWERS WILL LIKELY BE ON THE INCREASE WEDNESDAY AFTN/EVE
ACROSS PARTS OF THE REGION AS STRONG LLVL SLY FLOW COMMENCES IN
RESPONSE TO THE APPROACH OF THE INTENSE UPR TROUGH. ACTIVITY WILL
LIKELY DEEPEN WITH TIME WEDNESDAY NIGHT AS MORE ROBUST
BUOYANCY/BOUNDARY LAYER MOISTURE BEGIN TO SURGE TO THE CST AND DEEP
LAYER WIND FIELDS INCREASE. WHILE THE RISK OF SVR WEATHER WILL
ESCALATE JUST BEYOND THE DAY 2 PERIOD /ENDING 12Z THURSDAY/...ISOLD
STORMS MAY BEGIN TO EXHIBIT SOME ORGANIZATION AS EARLY AS 09-12Z
THURSDAY. SUFFICIENT LLVL TURNING WILL EXIST FOR AT LEAST A LOW
PROBABILITY OF A TORNADO OR TWO INVOF THE WRMFNT.

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Severe Weather activity is likely the next 2 days. This is mainly going to be late evening Weds through Thursday event. Hail and damaging winds will be main risk, however there will be a tornado threat mainly in the western half of Oklahoma.





DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0102 AM CDT WED OCT 28 2009

VALID 281200Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SRN PLAINS...

...SYNOPSIS...
00Z UPPER AIR ANALYSIS SHOWED VERY STRONG MID-UPPER LEVEL WINDS
DIVING SSEWD ALONG THE WEST COAST WITH THIS FLOW REGIME CONTINUING
TO CARVE OUT A CLOSED MID/UPPER LEVEL LOW OVER NRN AZ/FOUR CORNERS
REGION BY 12Z TODAY. THIS SYSTEM WILL SHIFT ENEWD TO THE CENTRAL/
SRN HIGH PLAINS BY 12Z THURSDAY...AS THE STRONG MID/UPPER LEVEL FLOW
ROUNDS THE BASE OF THE UPPER TROUGH/CLOSED LOW.

IN THE LOW LEVELS...A SURFACE LOW WILL CONTINUE TO DEVELOP OVER NERN
NM THROUGH THE FIRST HALF OF THE FORECAST PERIOD...AND THEN MOVE
NEWD INTO WRN KS THIS EVENING...POTENTIALLY REACHING SWRN NEB BY 12Z
THURSDAY. BY EARLY WEDNESDAY EVENING...A SRN PLAINS LEE TROUGH WILL
BE OVERTAKEN BY A COLD FRONT ACCOMPANYING THE SWRN U.S. CLOSED UPPER
LOW/TROUGH. AS THE SURFACE LOW PROGRESSES NEWD INTO WRN KS...THE
TRAILING COLD FRONT WILL ADVANCE EWD TONIGHT REACHING CENTRAL PARTS
OF KS/OK AND TX BY END OF FORECAST PERIOD. MEANWHILE...A FRONT OVER
THE NRN GULF BASIN EARLY TODAY SHOULD RETURN FAIRLY QUICKLY NWD
GIVEN DEVELOPING AND STRENGTHENING SLY LOW LEVEL FLOW ACROSS LOWER
MS VALLEY AND SRN PLAINS. THIS BOUNDARY SHOULD EXTEND FROM LA NWWD
TO THE RED RIVER VALLEY BY 12Z THURSDAY.

...SRN PLAINS...
MODELS CONTINUE TO ADVERTISE BOUNDARY LAYER MOISTURE RETURNING IN
EARNEST ACROSS THE SRN PLAINS THIS AFTERNOON INTO THE EVENING/
OVERNIGHT PERIOD...AS SLY LOW LEVEL FLOW INCREASES DOWNSTREAM FROM
THE APPROACHING UPPER LOW. SURFACE DEW POINTS IN EXCESS OF 60 DEG F
WILL BE SURGING INTO PARTS OF NWRN TX/SRN OK BY EARLY EVENING.
GIVEN THE LATE ARRIVAL OF THIS MOISTURE AND STRONGER FORCING FOR
ASCENT NOT REACHING W TX/SWRN KS UNTIL AFTER 29/00Z...THE POTENTIAL
FOR DIURNAL TSTM DEVELOPMENT ALONG THE LEE TROUGH REMAINS QUITE LOW.

MORE LIKELY SCENARIO REMAINS WITH POST-SUNSET TSTMS TO EVOLVE ALONG
THE TX/OK BORDER SWD INTO THE TRANSPECOS REGION AS PRE-FRONTAL AIR
MASS CONTINUES TO MOISTEN AND LARGE-SCALE HEIGHT FALLS SPREAD EWD
CONCURRENT WITH THE COLD FRONT. FORECAST DEEP LAYER SHEAR PROFILES
WILL BE QUITE STRONG AND DESPITE THE POST-DIURNAL TSTM DEVELOPMENT
AND WEAK INSTABILITY...INITIAL STORMS MAY BE SUPERCELLS WITH LARGE
HAIL...DAMAGING WINDS AND PERHAPS A TORNADO OR TWO. FAST NEWD STORM
MOTIONS SUGGEST INITIAL ACTIVITY COULD MOVE INTO PARTS OF SWRN KS AS
SURFACE LOW TRACKS INTO WRN KS. BACKING LOW/MID-LEVEL WIND FIELDS
WITH TIME AND INCREASING ASCENT WILL RESULT IN AN EXPANDING SQUALL
LINE REACHING FROM CENTRAL/ERN KS TO CENTRAL OK/TX BY 12Z THURSDAY.
WHILE SEVERE THREAT WILL TRANSITION INTO MOSTLY DAMAGING WINDS...
ISOLATED TORNADOES CANNOT BE RULED OUT...PARTICULARLY WHERE STORMS
CAN REMAIN DISCRETE THE LONGEST WITHIN THE MORE ROBUST BOUNDARY
LAYER MOISTURE ACROSS CNTRL/NRN TX INTO WRN OK.



DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1232 AM CDT WED OCT 28 2009

VALID 291200Z - 301200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM TX/LA...NWD TO SRN MO...

...TX/LA...NWD TO SRN MO...

NRN PIECE OF BIFURCATING UPPER TROUGH WILL EJECT ACROSS CO INTO THE
NRN RED RIVER REGION OF NWRN MN BY THE END OF THE PERIOD WHILE A
SLOWER OPEN SHORTWAVE BEGINS TO SHIFT EWD ACROSS NM INTO FAR WEST
TX. A VERY STRONG JET CORE WILL DEVELOP ON FORWARD SIDE OF LONGWAVE
AND EXTEND FROM THE TX SOUTH PLAINS...NEWD INTO THE UPPER MS
VALLEY...DISPLACED A FEW HUNDRED MILES TO THE COOL SIDE OF FRONTAL
ZONE. EVEN SO...STRONG MID LEVEL FLOW WILL OVERSPREAD ADVANCING
COLD FRONT SUCH THAT ANY STORMS THAT MANAGE TO ROOT INTO MOISTENING
WARM SECTOR BOUNDARY LAYER WILL HAVE A PROPENSITY TO ROTATE. MODELS
CONTINUE TO SUGGEST MARITIME AIRMASS WILL INDEED RETURN ACROSS TX
LATE DAY1 INTO EARLY DAY2 WITH MID 60S SFC DEW POINTS EXPECTED AS
FAR NORTH AS CNTRL OK AHEAD OF COLD FRONT. MOISTURE PLUME WILL
GRADUALLY EXPAND AND SPREAD NWD ACROSS THE LOWER MS VALLEY AND
IMMEDIATE GULF COAST BY THE END OF THE PERIOD WITH 70+ DEW POINTS
LIKELY INTO SRN AR/MS. ALTHOUGH PRIMARY FORCING WILL SPREAD
INITIALLY TO THE NORTH OF THE CURRENT DAY2 OUTLOOK...IT APPEARS A
SQUALL LINE SHOULD DEVELOP ALONG FRONTAL ZONE AS IT INTERACTS WITH
INCREASINGLY MOIST...BUT ONLY MODESTLY UNSTABLE...ENVIRONMENT ACROSS
OK/TX. A CONSIDERABLE AMOUNT OF CONVECTION MAY ALSO TRAIL THE
LEADING WIND SHIFT AS FRONTAL ASCENT MAY BE REQUIRED FOR CONVECTIVE
INITIATION/MAINTENANCE OF LIKELY LINEAR MCS. IT/S NOT ENTIRELY
CLEAR HOW MUCH PRE-FRONTAL ACTIVITY WILL DEVELOP WITHIN STRONGLY
SHEARED AND MOIST WARM SECTOR. CURRENT THINKING IS THE MOST LIKELY
STORM MODE WILL BE A SQUALL LINE WITH EMBEDDED BOW-TYPE STRUCTURES
AND POSSIBLE SUPERCELLS. FORECAST SOUNDINGS EVEN AT 29/12Z ARE
QUITE IMPRESSIVE...SHEAR WISE...ACROSS PARTS OF NCNTRL TX INTO
SCNTRL OK...THOUGH INSTABILITY IS A BIT MEAGER. DAMAGING WINDS
APPEAR TO BE THE GREATEST RISK WITH THIS CONVECTIVE EVENT...ALONG
WITH ISOLATED TORNADOES...ESPECIALLY IF DISCRETE SUPERCELLS CAN
DEVELOP AHEAD OF MCS. ACTIVITY SHOULD PROGRESS ACROSS OK/TX INTO
THE LOWER/MID MS VALLEY DURING THE AFTERNOON/EVENING HOURS WITH
FRONTAL ZONE/MCS EXPECTED TO EXTEND FROM THE MOUTH OF THE SABINE
RIVER IN SERN TX/SWRN LA INTO WRN TN BY THE END OF THE PERIOD.

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DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT WED OCT 28 2009

VALID 281630Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE SRN
PLAINS...

...SYNOPSIS...
DEEP AND CLOSED UPPER LOW LOCATED IN THE UT/AZ AREA THIS MORNING IS
FORECAST TO SHIFT EWD INTO NM TONIGHT...AS STRONGER WINDS ALOFT
DEVELOP OVER THE CENTRAL/SRN HIGH PLAINS...IN RESPONSE TO
STRENGTHENING GRADIENT ALOFT. COMPLEX AREA OF SURFACE LOW PRESSURE
IS CURRENTLY LOCATED OVER THE CENTRAL/SRN ROCKIES. HOWEVER... MODELS
ARE CONSISTENT IN THE MAIN SURFACE LOW MOVING/DEVELOPING I THE LBB
AREA THIS EVENING...AND THEN ACCELERATING RAPIDLY NEWD INTO ERN KS
BY THU MORNING...AHEAD OF EVOLVING WIND MAX ALOFT. PRIMARY CONCERN
FOR SEVERE CONVECTION IS EXPECTED ALONG AND AHEAD OF DEEPENING
SURFACE LOW AND SWD TRAILING COLD FRONT.

...SRN PLAINS...
LATEST SATELLITE PW DATA AND PUSH OF MID/UPPER 60 DEWPOINTS INTO SRN
TX INDICATES RAPID MOISTURE ADVECTION IS ALREADY UNDERWAY...AND
SHOULD CONTINUE NWD ACROSS MUCH OF TX AND OK INTO THE OVERNIGHT
HOURS. STRONG CAPPING AND WEAK FORCING SHOULD LIMIT CONVECTIVE
DEVELOPMENT THROUGH MOST OR ALL OF THE DAYLIGHT HOURS ACROSS THE
SLIGHT RISK AREA. HOWEVER...THE COMBINATION OF LARGE SCALE FORCING
SPREADING IN FROM THE WEST...INCREASING MOISTURE/INSTABILITY AND LOW
LEVEL CONVERGENCE SHOULD LEAD TO THE DEVELOPMENT OF STRONG STORMS
ALONG AND EAST OF SURFACE LOW/FRONT ACROSS THE SRN HIGH PLAINS THIS
EVENING. STRONG MOSTLY SSWLY UNIDIRECTIONAL WINDS ALOFT SUGGEST THE
STORMS ARE LIKELY TO EVOLVE RAPIDLY INTO A SQUALL LINE AND SHIFT
QUICKLY EWD OVERNIGHT. DESPITE RELATIVELY WEAK LOW LEVEL LAPSE
RATES...MUCAPES FROM 500 TO 1000 J/KG ALONG WITH STRENGTHENING DEEP
SSWLY WIND FIELDS...AND 700 MB SPEEDS AOA 50 KT FAVORS DAMAGING
WINDS AS THE PRIMARY THREAT. HOWEVER...DEEP LAYER SHEAR AT 50 TO 60
KT AND STRONGLY CURVED LOW LEVEL HODOGRAPHS...1 KM SHEAR AROUND 40
KT...INDICATES TORNADOES WOULD ALSO BE POSSIBLE WITH EMBEDDED
BOWS/LEWPS AND ANY DISCRETE CELLS THAT DEVELOP AHEAD OF THE SQUALL
LINE.

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DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0257 PM CDT WED OCT 28 2009

VALID 282000Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SOUTHERN PLAINS...

...SOUTHERN PLAINS TONIGHT...
PREVIOUSLY DISCUSSED SCENARIO STILL HOLDS...WITH AN INCREASING
SEVERE THREAT EXPECTED LATER THIS EVENING/OVERNIGHT MAINLY ACROSS
PORTIONS OF NORTHWEST/NORTH CENTRAL TX AND WESTERN/CENTRAL OK. A
VERY MOIST AIRMASS WITH AROUND 70F SURFACE DEWPOINTS WILL CONTINUE
TO MOVE INLAND ACROSS SOUTHEAST TX THE REMAINDER OF THE
PERIOD...WITH INCREASING MERIDIONAL TRAJECTORIES AHEAD OF THE
SOUTHERN ROCKIES UPPER TROUGH AND SIGNIFICANTLY STRENGTHENING LOW
LEVEL FLOW /55-60 KT AROUND 850 MB/ FOSTERING AN AGGRESSIVE MOISTURE
RETURN SCENARIO ACROSS TX INTO OK TONIGHT. AS SURFACE CYCLOGENESIS
CONTINUES TO OCCUR ACROSS THE TX PANHANDLE/FAR WESTERN OK INTO THIS
EVENING...LATEST GUIDANCE IMPLIES THAT STORMS COULD INCREASE
ALONG/JUST AHEAD OF THE SURFACE FRONT/TROUGH BY AROUND
02Z-04Z...WITH POTENTIAL FOR SURFACE OR NEAR-SURFACE BASED TSTMS TO
ACTUALLY INCREASE THROUGH THE NIGHT ACROSS NORTHWEST/NORTH CENTRAL
TX AND WESTERN/CENTRAL OK AS A MOIST LOW LEVEL INFLUX CONTINUES.
WHILE A SQUALL LINE SHOULD ULTIMATELY EVOLVE
OVERNIGHT...QUASI-DISCRETE STORMS AND/OR QLCS EMBEDDED BOWS/LEWPS
MAY POSE A TORNADO RISK ALONG WITH DAMAGING WINDS THROUGH THE
PREDAWN HOURS.

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Quick update. Showers and storms forming ahead of the squall line in SC and Eastern Oklahoma. These extend down past Dallas/Fort Worth where one has developed pretty strong rotation and is now tornado warned. We may have a situation of quick spin ups tonight with the high shear environment today. No watches out at all right now though.



DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1256 AM CDT THU OCT 29 2009

VALID 291200Z - 301200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE SRN AND CNTRL
PLAINS INTO THE LOWER MS VALLEY...

...SYNOPSIS...

POSITIVE TILT UPPER TROUGH OVER THE SWRN STATES WILL ADVANCE SLOWLY
EAST THIS PERIOD WHILE A SERIES OF IMPULSES MOVE THROUGH THIS
FEATURE. LEAD IMPULSE CURRENTLY OVER THE SRN AND CNTRL HIGH PLAINS
WILL LIFT NWD THROUGH THE NRN PLAINS EARLY THURSDAY. A STRONGER
UPPER JET NOW ROUNDING THE BASE OF THE TROUGH WILL EJECT NEWD
THROUGH THE SRN PLAINS THIS AFTERNOON...REACHING THE CNTRL PLAINS BY
EARLY EVENING. AT THE SURFACE A WARM FRONT WILL LIFT NWD ACROSS NERN
TX...SERN OK AND THE LOWER MS VALLEY. A SURFACE LOW WILL DEVELOP
NEWD ALONG THE FRONT IN ASSOCIATION WITH EJECTING UPPER JET. THIS
FEATURE WILL REACH THE UPPER MS VALLEY LATE THURSDAY NIGHT. THE
TRAILING COLD FRONT WILL ADVANCE SLOWLY EWD THROUGH THE CNTRL AND
SRN PLAINS TODAY AND MID-LOWER MS VALLEY OVERNIGHT.

...SRN PLAINS THROUGH SERN KS...SWRN MO AND LOWER MS VALLEY...

RICH GULF MOISTURE WITH LOW 60S DEWPOINTS AS FAR NORTH AS ERN OK AND
LOW 70S ACROSS ERN TX AND THE LOWER MS VALLEY WILL ADVECT NWD IN
WAKE OF RETREATING WARM FRONT ALONG STRONG LOW LEVEL JET. MODEST MID
LEVEL LAPSE RATES AND AREAS OF CLOUDS WILL LIKELY LIMIT MLCAPE TO
AOB 1500 J/KG ACROSS MUCH OF THE WARM SECTOR...BUT MLCAPE COULD
APPROACH 2000 J/KG WHERE LOW CLOUDS CAN MIX OUT.

SCATTERED THUNDERSTORMS...MOST OF WHICH SHOULD BE AT LEAST SLIGHTLY
ELEVATED...MAY BE ONGOING EARLY THURSDAY MAINLY FROM NERN TX...ERN
OK INTO THE LOWER MS VALLEY WITHIN ZONE OF STRONGER ISENTROPIC LIFT
NORTH OF RETREATING WARM FRONT. UPPER FLOW WILL REMAIN MERIDIONAL
EAST OF UPPER TROUGH AND MAY RESULT IN AT LEAST SLIGHT WARMING IN
THE 850-500 MB LAYER ACROSS WARM SECTOR. THIS AND TENDENCY FOR
DEEPER FORCING ASSOCIATED WITH EJECTING UPPER JET TO REMAIN POST
FRONTAL RAISES CONCERNS THAT THE THERMODYNAMIC ENVIRONMENT COULD
POTENTIALLY LIMIT THE ROBUSTNESS AND EXTENT OF SURFACE BASED
THUNDERSTORMS IN WARM SECTOR. HOWEVER...VERTICAL SHEAR AND 0-1 KM
HODOGRAPHS WILL REMAIN SUFFICIENT FOR A THREAT OF SUPERCELLS AND
ISOLATED TORNADOES WITH ANY SURFACE BASED STORMS THAT DEVELOP.

OTHER STORMS WILL LIKELY CONTINUE WITHIN CORRIDOR OF DEEP ASCENT
ALONG BAROCLINIC ZONE AS IT ADVANCES EAST THROUGH TX...OK AND ERN KS
DURING THE DAY. THE NATURE OF THE FORCING AND MERIDIONAL UPPER FLOW
WILL PROMOTE PRIMARILY LINEAR STRUCTURES. HOWEVER...STORMS WILL
REMAIN WITHIN AN ENVIRONMENT CHARACTERIZED BY 50+ KT BULK SHEAR AND
SUFFICIENTLY LARGE LOW LEVEL HODOGRAPHS FOR EMBEDDED SUPERCELLS AND
BOWING SEGMENTS. DAMAGING WIND WILL BE THE MAIN THREAT WITH THIS
ACTIVITY...BUT ISOLATED TORNADOES WILL ALSO BE POSSIBLE. THREAT FOR
ISOLATED DAMAGING WIND MAY EXTEND AS FAR NORTH AS SERN KS AND SRN
MO...BUT NWD EXTENT OF THREAT WILL BE LIMITED BY WEAK INSTABILITY.

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MESOSCALE DISCUSSION 2151
NWS STORM PREDICTION CENTER NORMAN OK
0107 AM CDT THU OCT 29 2009

AREAS AFFECTED...PARTS OF SWRN/S-CNTRL OK INTO NWRN/N-CNTRL TX

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 290607Z - 290700Z

THE THREAT FOR SEVERE STORMS CAPABLE OF DAMAGING WINDS AND PERHAPS
TORNADOES IS EXPECTED TO INCREASE ACROSS AREA EARLY THIS MORNING. A
WW WILL BE REQUIRED.

RECENT TRENDS IN VOLUMETRIC RADAR DATA INDICATE STORMS GRADUALLY
DEEPENING/INTENSIFYING ALONG PACIFIC FRONT FROM NEAR CSM SSWWD TO
JUST E OF BPG AS OF 0550Z. THUS FAR...FRONTAL FORCING HAS REMAINED
TO THE W OF RICHER BOUNDARY LAYER MOISTURE AND RESULTANT STRONGER
INSTABILITY...EFFECTIVELY LIMITING STORM INTENSITY. HOWEVER AS
FRONT CONTINUES SLOWLY EWD...IT WILL ENCOUNTER MID/UPPER 60S
DEWPOINTS BEING ADVECTED NWWD BY 50-60 KT LLJ. THIS SHOULD SUPPORT
THE CONTINUED INTENSIFICATION OF STORMS...LIKELY IN THE FORM OF A
LINEAR CONVECTIVE SYSTEM. THE PRIMARY FACTORS CURRENTLY LIMITING A
MORE SUBSTANTIAL SEVERE THREAT APPEAR TO BE ANAFRONTAL FORCING ALONG
FRONT AND TENDENCY FOR STRONGER SYNOPTIC-SCALE FORCING FOR ASCENT TO
SHIFT NWD INTO THE CNTRL PLAINS THROUGH THE EARLY MORNING HOURS.

AREA VWPS AND PROFILERS INDICATE QUITE STRONG AMBIENT WIND
FIELD...RESULTING IN 0-1 AND 0-6 KM BULK SHEAR OF 40-45 KT AND 60 KT
RESPECTIVELY. AS SUCH...THE POTENTIAL WILL EXIST FOR EMBEDDED
SUPERCELL STRUCTURES CAPABLE OF TORNADOES...IN ADDITION TO THE
THREAT FOR DAMAGING WINDS SHOULD STORMS BECOME FIRMLY ROOTED IN
MOISTENING BOUNDARY LAYER.

A SEPARATE AREA OF TSTMS HAS ALSO RECENTLY INTENSIFIED NEAR OR S OF
THE METROPLEX...DRIVEN LARGELY BY LOW-LEVEL WAA INVOF WARM FRONT
RETREATING NWD TOWARD THE RED RIVER. HERE...BOUNDARY LAYER IS QUITE
MOIST WITH DEWPOINTS AROUND 70F...CONTRIBUTING TO AT LEAST WEAK
CONVECTIVE INSTABILITY. GIVEN THE STRONGLY SHEARED
ENVIRONMENT...POTENTIAL WILL EXIST FOR MORE DISCRETE TORNADIC
SUPERCELLS.

..MEAD.. 10/29/2009

[venture]

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 778
NWS STORM PREDICTION CENTER NORMAN OK
120 AM CDT THU OCT 29 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

SOUTHERN OKLAHOMA
NORTH CENTRAL TEXAS

EFFECTIVE THIS THURSDAY MORNING FROM 120 AM UNTIL 700 AM CDT.

SEVERAL TORNADOES
WIDELY SCATTERED DAMAGING WINDS
ISOLATED WIND GUSTS TO 70 MPH POSSIBLE
WIDELY SCATTERED LARGE HAIL TO 1.0 INCH IN DIAMETER

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE
MILES EITHER SIDE OF A LINE FROM 25 MILES NORTH OF MCALESTER
OKLAHOMA TO 40 MILES WEST OF CORSICANA TEXAS. FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU8).

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.

DISCUSSION...STORMS HAVE BEEN SLOWLY STRENGTHENING THE PAST COUPLE
OF HOURS ACROSS NRN TEXAS. WARM FRONT EXTENDED FROM NEAR FSI TO
GGG...AND DEWPOINTS NEAR 70 IN THE WARM SECTION APPEARED TO BE
AIDING IN THE DEVELOPMENT OF NEAR SURFACE BASED STORMS. THE
COMBINATION OF THIS MOIST ENVIRONMENT AND 1 KM SHEAR AT 40-50 KT
WILL BE FAVORABLE FOR ROTATING STORMS AND TORNADOES. AS THE WARM
FRONT CONTINUES TO RETREAT NWD THROUGH THE EARLY MORNING HOURS...THE
THREAT FOR TORNADOES WILL SPREAD INTO SRN OK.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
MEAN STORM MOTION VECTOR 20040.

----
WW 778 TORNADO OK TX 290620Z - 291200Z
AXIS..60 STATUTE MILES EITHER SIDE OF LINE..
25N MLC/MCALESTER OK/ - 40W CRS/CORSICANA TX/ ..AVIATION COORDS.. 50NM EITHER SIDE /24N MLC - 24NNE ACT/ HAIL SURFACE AND ALOFT..1 INCH. WIND GUSTS..60 KNOTS.
MAX TOPS TO 500. MEAN STORM MOTION VECTOR 20040.


Ulletin - immediate broadcast requested
tornado watch outline update for wt 778
nws storm prediction center norman ok
120 am cdt thu oct 29 2009

tornado watch 778 is in effect until 700 am cdt for the
following locations

okc005-013-019-023-029-049-063-069-077-085-095-099-121-123-125-
127-133-291200-
/o.new.kwns.to.a.0778.091029t0620z-091029t1200z/

ok
. Oklahoma counties included are

atoka bryan carter
choctaw coal garvin
hughes johnston latimer
love marshall murray
pittsburg pontotoc pottawatomie
pushmataha seminole

[venture]

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 779
NWS STORM PREDICTION CENTER NORMAN OK
200 AM CDT THU OCT 29 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

CENTRAL AND SOUTHWESTERN OKLAHOMA
NORTHWESTERN TEXAS

EFFECTIVE THIS THURSDAY MORNING FROM 200 AM UNTIL 900 AM CDT.

SEVERAL TORNADOES
WIDELY SCATTERED DAMAGING WINDS
ISOLATED WIND GUSTS TO 70 MPH POSSIBLE
WIDELY SCATTERED LARGE HAIL TO 1.0 INCH IN DIAMETER

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE
MILES EAST AND WEST OF A LINE FROM 25 MILES SOUTH SOUTHEAST OF
ABILENE TEXAS TO 40 MILES NORTH OF OKLAHOMA CITY OKLAHOMA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU9).

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 778...

DISCUSSION...A LINE OF STORMS FROM WEST CENTRAL OK SWWD INTO NWRN TX
WAS SLOWLY BECOMING BETTER ORGANIZED...AS STRONGER FORCING SPREADS
IN FROM THE SOUTHWEST. STRONGER CONVECTION CURRENTLY IS LOCATED
ALONG OR JUST BEHIND COLD FRONT. AS THE LINE MOVES SLOWLY EWD INTO A
MODERATELY UNSTABLE AIR MASS AND DEWPOINTS IN THE MID 60S...THE
POTENTIAL FOR SURFACE BASED STORMS WILL INCREASE. ALSO...GIVEN
EFFECTIVE SHEAR AT 60-70 KT AND 1 KM SRH IN THE 400-500 M2/S2
RANGE...ROTATING STORMS ARE LIKELY WITH EMBEDDED BOWS/WIND DAMAGE
AND POSSIBLY TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
MEAN STORM MOTION VECTOR 21040.

New Tornado Watch including the rest of the Metro.

WW 779 TORNADO OK TX 290700Z - 291400Z
AXIS..60 STATUTE MILES EAST AND WEST OF LINE..
25SSE ABI/ABILENE TX/ - 40N OKC/OKLAHOMA CITY OK/ ..AVIATION COORDS.. 50NM E/W /29SE ABI - 27SE END/ HAIL SURFACE AND ALOFT..1 INCH. WIND GUSTS..60 KNOTS.
MAX TOPS TO 500. MEAN STORM MOTION VECTOR 21040.

[Thunder]

I hope Karrie is sleeping.

[venture]

MESOSCALE DISCUSSION 2152
NWS STORM PREDICTION CENTER NORMAN OK
0340 AM CDT THU OCT 29 2009

AREAS AFFECTED...PARTS OF CNTRL/SRN OK INTO NRN TX

CONCERNING...TORNADO WATCH 778...779...

VALID 290840Z - 291015Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 778...779...CONTINUES.

THE THREAT FOR DAMAGING WIND GUSTS AND TORNADOES CONTINUES ACROSS WW
AREAS.

EXCEPT FOR A SMALL CLUSTER OF DEEP SHOWERS/TSTMS OVER BRYAN COUNTY
OK...MOIST CONVECTION HAS DIMINISHED ACROSS WW 778 AREA. BASED ON
2-HR PRESSURE TENDENCIES...IT IS POSSIBLE THAT THE STRONGEST
LOW-LEVEL FORCING FOR ASCENT /I.E. WAA/ IS SHIFTING NNEWD TOWARD THE
OZARK PLATEAU. HOWEVER...RADAR DATA DO CONTINUE TO INDICATE WEAK
SHOWERS PRESENT FROM THE HILL COUNTRY NWD THROUGH N-CNTRL
TX...INDICATIVE OF BROAD WAA OCCURRING ALONG 50-60 KT LLJ. AS
SUCH...THE POTENTIAL EXISTS FOR STORM REGENERATION...PARTICULARLY AS
LINEAR SYSTEM APPROACHES FROM THE W. KINEMATIC ENVIRONMENT WILL
REMAIN QUITE FAVORABLE FOR SUPERCELLS CAPABLE OF TORNADOES.

FARTHER W ACROSS WW779...BROKEN CONVECTIVE BAND WHICH EARLIER
INTENSIFIED...NOW APPEARS TO BE STRUGGLING WITH ANAFRONTAL AIRFLOW
REGIME. THIS IS LIKELY BEGIN EXACERBATED BY CONVECTIVE OUTFLOW
GENERATED BY ONGOING STORMS. AS OF 0820Z...THE STRONGEST STORMS
WERE LOCATED OVER WA****A AND KIOWA COUNTIES AND FARTHER S OVER
WILBARGER AND BAYLOR COUNTIES IN NW TX. THE WILBARGER/BAYLOR COUNTY
COMPLEX HAS EXHIBITED BOWING PROPERTIES WHILE FORWARD-PROPAGATING
NEWD AT AROUND 45 KT.

BASED ON CURRENT RADAR TRENDS...IT APPEARS THAT THE REGION BOUNDED
BY I-40...U.S. 287 AND I-35 WILL BE THE MOST LIKELY AREA FOR
ISOLATED SEVERE WEATHER THROUGH 10-11Z. HERE...THE STRONGER
SYNOPTIC-FORCING FOR ASCENT ATTENDANT TO MID/UPPER JET STREAK
LIFTING NWD THROUGH THE HIGH PLAINS WILL REMAIN COINCIDENT WITH
MOISTENING/DESTABILIZING PRE-FRONTAL WARM SECTOR.