2012 U.S Severe Weather (Videos-Photos-Stats-Forecasts)

[Ntxw]

GFS is joining the Euro in keeping the trough out west with the ridge holding strong. Again this would probably mean localized areas of severe weather in the northern plains/high plains and southern Canadian prairies. Not sure this looks like an outbreak there might be a fast moving front and some precipitation is post frontal in that region. A lot of jet energy but not zonal like one would look for in an outbreak.

[SaskatchewanScreamer]

Hmmmmm so those luscious well developed hanging plants I *just* purchased should probably go into the shed and garage Wednesday night (if not Tuesday)?

I hate losing plants to hail/high winds at any time but this early in the season would be beyond depressing (never mind having more $$$$$$$ damage).

p.s. I am not enthusiatic re any thoughts of tornadoes &/or straight line winds (we lost a barn to that a couple of years ago) and if by chance they land up here, or anywhere on the Great Plains, I hope they pick on empty fields (please).

[cycloneye]

SPC is still not bullish on a big outbreak in the near future.

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0321 AM CDT MON MAY 21 2012

VALID 241200Z - 291200Z

...DISCUSSION...
WHILE THE ECMWF AND GFS AGREE THAT A BELT OF STRONGER FLOW WILL BE
SHUNTED INTO THE MIDDLE OF THE U.S. DURING THE DAY3-4 PERIOD
SIGNIFICANT DIFFERENCES EMERGE REGARDING INDIVIDUAL SHORT-WAVES BY
THURSDAY. THE GFS IS NOTABLY FASTER WITH AN EJECTING SHORT-WAVE
TROUGH ACROSS THE UPPER MS VALLEY WHILE THE ECMWF LAGS CONSIDERABLY
OVER THE CNTRL HIGH PLAINS AT 25/00Z. GIVEN THE EXPECTED WARM EML
THAT WILL BE IN PLACE AHEAD OF THE COLD FRONT THERE IS TOO MUCH
UNCERTAINTY AT THIS TIME TO WARRANT A RISK OF ORGANIZED SEVERE
THUNDERSTORMS.

BEYOND DAY4...UPPER HEIGHTS ARE EXPECTED TO RISE ACROSS MUCH OF THE
ERN CONUS WITH THE CENTER OF A STRENGTHENING HIGH PRESSURE SYSTEM
OVER THE TN VALLEY. IF SUFFICIENT MOISTURE CAN RETURN TO THE HIGH
PLAINS THEN STRONG/SEVERE TSTMS MAY EVOLVE ACROSS THAT REGION.

..DARROW.. 05/21/2012

[SaskatchewanScreamer]

Thank you for the update Cycloneye.

[RL3AO]

One year tomorrow since Joplin.

[cycloneye]

Still anything of significance on the 4-8 day outlook by SPC.

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0321 AM CDT TUE MAY 22 2012

VALID 251200Z - 301200Z

...DISCUSSION...
CONSIDERABLE DIFFERENCES BEGIN TO EMERGE AMONG THE MEDIUM RANGE
MODELS REGARDING THE TIMING OF EJECTING SHORT-WAVES AS THEY TRAVERSE
THE GREAT BASIN INTO THE PLAINS...ATOP A STRENGTHENING/BUILDING HIGH
PRESSURE DOME...THEN ACROSS THE GREAT LAKES REGION. LATEST ECMWF
AND GFS AGREE THAT A DOMINANT HIGH PRESSURE SYSTEM WILL ESTABLISH
ITSELF OVER THE TN VALLEY. THIS FEATURE WILL ENSURE EJECTING
SHORT-WAVES WILL STRUGGLE TO INFLUENCE AREAS SOUTH OF I-70 IN THE
PLAINS BUT RATHER HAVE GREATER IMPACT ON AREAS CLOSER TO THE
U.S./CANADIAN BORDER AS WARM MID LEVEL TEMPERATURES SERVE TO CAP
MUCH OF THE REGION. WHILE CONVECTION WILL LIKELY EVOLVE ALONG
NRN/ERN EDGE OF STRONG CAP WITHIN WARM ADVECTION ZONES...UNTIL
MARITIME TROPICAL AIRMASS CAN RETURN NWD INTO THE CNTRL U.S. WARM
SECTOR TSTMS MAY STRUGGLE TO OVERCOME THE INFLUENCE OF SAID MID
LEVEL ANTICYCLONE.

..DARROW.. 05/22/2012

[cycloneye]

Here are the latest stats for 2012 that have been updated.

Code: Select all

Month Total Torn Hail Wind
Jan 2012 554 97 92 365
Feb 2012 714 63 188 463
Mar 2012 1967 225 1146 596
Apr 2012 1903 233 1053 617
May 2012 1351 71 739 541
Jun 2012 0 0 0 0
Jul 2012 0 0 0 0
Aug 2012 0 0 0 0
Sep 2012 0 0 0 0
Oct 2012 0 0 0 0
Nov 2012 0 0 0 0
Dec 2012 0 0 0 0
TOTAL 6489 689 3218 2582


[SaskatchewanScreamer]

Am copying and pasting the above to the Canadian thread as well. Thank you Cycloneye!

[Cyclenall]

Still anything of significance on the 4-8 day outlook by SPC.

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0321 AM CDT TUE MAY 22 2012

VALID 251200Z - 301200Z

...DISCUSSION...
CONSIDERABLE DIFFERENCES BEGIN TO EMERGE AMONG THE MEDIUM RANGE
MODELS REGARDING THE TIMING OF EJECTING SHORT-WAVES AS THEY TRAVERSE
THE GREAT BASIN INTO THE PLAINS...ATOP A STRENGTHENING/BUILDING HIGH
PRESSURE DOME...THEN ACROSS THE GREAT LAKES REGION. LATEST ECMWF
AND GFS AGREE THAT A DOMINANT HIGH PRESSURE SYSTEM WILL ESTABLISH
ITSELF OVER THE TN VALLEY. THIS FEATURE WILL ENSURE EJECTING
SHORT-WAVES WILL STRUGGLE TO INFLUENCE AREAS SOUTH OF I-70 IN THE
PLAINS BUT RATHER HAVE GREATER IMPACT ON AREAS CLOSER TO THE
U.S./CANADIAN BORDER AS WARM MID LEVEL TEMPERATURES SERVE TO CAP
MUCH OF THE REGION. WHILE CONVECTION WILL LIKELY EVOLVE ALONG
NRN/ERN EDGE OF STRONG CAP WITHIN WARM ADVECTION ZONES...UNTIL
MARITIME TROPICAL AIRMASS CAN RETURN NWD INTO THE CNTRL U.S. WARM
SECTOR TSTMS MAY STRUGGLE TO OVERCOME THE INFLUENCE OF SAID MID
LEVEL ANTICYCLONE.

..DARROW.. 05/22/2012

Two points about the bolded text: The main models seem to be highly divergent on not just this type of weather, but all now. Obviously its all inter-connected but temps., severe weather, and now maybe Bud are all low confidence. The 2nd is if nothing severe related happens, I want that High pressure to "go all out" and become a death ridge that blasts me with furnace heat and ramps the humidity up to extreme levels for weeks The later part of May 1911 will do .

[cycloneye]

Severe event on day 5

SPC is bullish on the upcomming outbreak on day 5. Let's see how it evolves as things fall into place.

ZCZC SPCSWOD48 ALL
ACUS48 KWNS 230829
SPC AC 230829

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0329 AM CDT WED MAY 23 2012

VALID 261200Z - 311200Z

...DISCUSSION...
LATEST MEDIUM RANGE MODEL GUIDANCE IS IN GENERAL AGREEMENT REGARDING
THE LIKELIHOOD FOR A SIGNIFICANT SHORT-WAVE TROUGH TO EJECT ACROSS
THE GREAT BASIN DURING THE DAY4 PERIOD THEN INTO THE NRN/CNTRL
PLAINS AND UPPER MS VALLEY BY DAY5. THIS FEATURE WILL INDUCE
SIGNIFICANT MID LEVEL HEIGHT FALLS WHICH WILL FLATTEN THE DOMINANT
TN VALLEY RIDGE. VERY WARM EML WILL EXPAND NWD ACROSS THE PLAINS
DURING THE DAY4 PERIOD WITH 14C AT 700MB EXPECTED TO SPREAD INTO SD
EARLY. ALONG THE NRN/ERN EDGE OF THIS WARM PLUME THERE WILL LIKELY
BE ROBUST ELEVATED CONVECTION DRIVEN BY STRONG LOW LEVEL WARM
ADVECTION. SOME OF THIS ACTIVITY COULD BE SEVERE BUT GIVEN THE
STRENGTHENING CAP WILL NOT INTRODUCE AN ORGANIZED SEVERE THREAT
DURING THE DAY4 PERIOD. HOWEVER...MUCH STRONGER FORCING ASSOCIATED
WITH THE EJECTING SHORT-WAVE TROUGH WILL LIKELY FOCUS SEVERE
THUNDERSTORMS FROM THE CNTRL PLAINS INTO THE UPPER MS VALLEY BY
SUNDAY AS A STRONG COLD FRONT SURGES EWD. SIGNIFICANT COOLING ALOFT
SHOULD ERODE THE CAP ENABLING MORE ORGANIZED DEVELOPMENT POSSIBLE.

..DARROW.. 05/23/2012



Uploaded with imageshack.us

[cycloneye]

SPC is more confident today of an outbreak on the 4-8 day period.

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0328 AM CDT THU MAY 24 2012

VALID 271200Z - 011200Z

...DISCUSSION...
THERE IS INCREASING CONFIDENCE...BASED ON LATEST MODEL
GUIDANCE...THAT A STRONG SHORT-WAVE TROUGH WILL EJECT INTO THE HIGH
PLAINS EARLY IN THE DAY4 PERIOD...THEN INTO THE UPPER MS
VALLEY/GREAT LAKES DAY5. THIS FEATURE SHOULD ERODE THE WARM EML
ACROSS MUCH OF THE MIDWEST SUCH THAT STRONG/SEVERE THUNDERSTORMS ARE
EXPECTED TO DEVELOP ALONG ADVANCING COLD FRONT. BY LATE IN THE WEEK
BOUNDARY LAYER MOISTURE SHOULD BE SUBSTANTIALLY HIGHER THAN
CURRENTLY OBSERVED ACROSS THE PLAINS. SRN EXTENT OF ORGANIZED
SEVERE EACH OF THESE DAYS IS SOMEWHAT IN QUESTION BUT LIKELY LIMITED
BY HEIGHT FALLS THAT SHOULD EXTEND INTO KS/MO.

..DARROW.. 05/24/2012

[cycloneye]

Here is the 4-8 forecast. Low confidence is the word here.

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0355 AM CDT FRI MAY 25 2012

VALID 281200Z - 021200Z

...DISCUSSION...
THE MEDIUM RANGE MODELS BEGIN THE DAY 4 TO 8 PERIOD IN GOOD
AGREEMENT WITH AN UPPER-LEVEL TROUGH EXTENDING SWD THROUGH THE NRN
AND CNTRL PLAINS ON MONDAY/DAY 4. BY LATE MONDAY AFTERNOON...A COLD
FRONT IS FORECAST TO BE LOCATED FROM THE WRN GREAT LAKES SSWWD INTO
THE MID-MO VALLEY. THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE ALONG
THIS BOUNDARY MONDAY AFTERNOON AND EVENING. GFS FORECAST SOUNDINGS
MONDAY EVENING FROM AROUND SPRINGFIELD MO NNEWD TO AROUND DAVENPORT
IA SHOW MODERATE TO STRONG INSTABILITY WITH AMPLE DEEP LAYER SHEAR
FOR SEVERE STORMS. WILL MAINTAIN AN ENHANCED SEVERE THREAT AREA
ALONG THIS CORRIDOR ON DAY 4. FOR TUESDAY/DAY 5...THE MODELS MOVE
THE UPPER-LEVEL TROUGH INTO THE GREAT LAKES REGION WITH THE COLD
FRONT ADVANCING QUICKLY SEWD ACROSS THE MID-MS VALLEY. AS THE FRONT
MOVES AWAY FROM THE STRONGER FORCING...THUNDERSTORM DEVELOPMENT
SHOULD BE MORE ISOLATED. THE GREATEST CONVECTIVE COVERAGE SHOULD
EXIST NEWD INTO THE CNTRL AND NRN APPALACHIAN MTNS WHERE STRONG
THUNDERSTORM ACTIVITY COULD OCCUR. A SEVERE THREAT MAY ALSO EXIST IN
THE SRN PLAINS AS MOISTURE RETURNS NWD DURING THE DAY. UNCERTAINTY
IS TOO GREAT TOO WARRANT A SEVERE THREAT AREA ON TUESDAY. ON
WEDNESDAY/DAY 6...BOTH THE GFS AND ECMWF BRING A SHORT-WAVE TROUGH
ESEWD ACROSS THE SRN PLAINS SUGGESTING A CONCENTRATED AREA OF SEVERE
THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE ALONG AN AXIS OF STRONG
INSTABILITY WEDNESDAY AFTERNOON AND EVENING. HOWEVER...UNCERTAINTY
EXISTS CONCERNING THE TIMING AND AMPLITUDE OF THE SHORTWAVE TROUGH
AND WILL NOT INTRODUCE AN ENHANCED SEVERE THREAT AREA FOR WEDNESDAY.
BEYOND DAY 6...THE MODELS AMPLIFY AND MOVE THE SHORTWAVE TROUGH EWD
INTO THE MID-MS VALLEY. THUNDERSTORMS WILL AGAIN BE POSSIBLE AHEAD
OF THE SYSTEM BUT CONFIDENCE IS NOT VERY HIGH CONCERNING THIS LATE
IN THE PERIOD.

..BROYLES.. 05/25/2012

[cycloneye]

Forecast for slight risk on day 3 on from the 28th thru the 29th.

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0226 AM CDT SAT MAY 26 2012

VALID 281200Z - 291200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE GREAT
LAKES...LOWER MO VALLEY AND MID MS VALLEY...

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

...MID MS VALLEY/LOWER OH VALLEY/GREAT LAKES...
SOUTHWEST FLOW WILL BE IN PLACE ACROSS THE UPPER MIDWEST AND GREAT
LAKES REGION MONDAY AS A COLD FRONT MOVES INTO THE REGION FROM THE
WEST. AHEAD OF THE FRONT...MODEL FORECASTS SHOW A PRONOUNCED
PRE-FRONTAL TROUGH WITH MODERATE INSTABILITY DEVELOPING ALONG THE
TROUGH BY AFTERNOON. IN ADDITION TO THE INSTABILITY...THE
COMBINATION OF A BROAD MID-LEVEL JET AND A WELL-FOCUSED LOW-LEVEL
JET WILL CREATE SHEAR PROFILES FAVORABLE FOR SEVERE STORMS. FORECAST
SOUNDINGS AT 29/00Z AT CHICAGO AND DETROIT SHOW MLCAPE VALUES OF
1000 TO 1500 J/KG WITH 30 TO 40 KT OF DEEP LAYER SHEAR. THIS
COMBINATION OF SHEAR AND INSTABILITY SHOULD SUPPORT SUPERCELL
STRUCTURES WITH LARGE HAIL. ORGANIZED LINE-SEGMENTS WILL ALSO BE
PROBABLE AND MCS DEVELOPMENT MAY OCCUR BY EARLY EVENING AS STORMS
INCREASE IN COVERAGE. THE LOW-LEVEL JET AND INSTABILITY AXIS SHOULD
BE CO-LOCATED HELPING TO CREATE AN ENVIRONMENT FAVORABLE FOR
DAMAGING WIND GUSTS. SEVERAL UNCERTAINTIES EXIST CONCERNING THE
OUTLOOK. THE FIRST IS THE TIMING OF THE COLD FRONT AND THE SECOND IS
THE TIMING OF THE UPPER-LEVEL TROUGH. A SLOWER SOLUTION WOULD RESULT
IN A SEVERE THREAT FURTHER TO THE WEST. FOR THIS REASON...HAVE DRAWN
THE WRN EDGE OF THE SLIGHT RISK AREA ACROSS ERN IA AND WRN WI WHERE
STORMS ARE FORECAST TO FIRST DEVELOP MONDAY AFTERNOON. MARGINAL
SEVERE STORMS MAY ALSO OCCUR JUST AHEAD OF THE UPPER-LEVEL LOW OVER
THE ARROWHEAD OF MN AND FURTHER TO THE EAST IN THE ERN GREAT LAKES
AND NRN APPALACHIAN MTNS WHERE MODERATE INSTABILITY IS FORECAST.

...SRN PLAINS...
WEST TO SOUTHWEST FLOW SHOULD BE IN PLACE ACROSS THE SRN PLAINS
MONDAY. AN AXIS OF MODERATE TO STRONG INSTABILITY SHOULD DEVELOP
FROM WEST TX EXTENDING NEWD ACROSS CNTRL OK MONDAY AFTERNOON. AS SFC
TEMPS WARM DURING THE DAY AND THE CAP WEAKENS...SCATTERED
THUNDERSTORM INITIATION SEEMS PROBABLE ACROSS NORTHWEST TX AND
SOUTHWEST OK. THE INSTABILITY AND SHEAR ENVIRONMENT SHOULD BE
SUPPORTIVE OF SEVERE STORMS. FORECAST SOUNDINGS AT 29/00Z AT WICHITA
FALLS SHOW MLCAPE OF 2000 TO 2500 J/KG WITH AROUND 40 KT OF DEEP
LAYER SHEAR. THIS SHOULD SUPPORT A THREAT FOR SUPERCELLS WITH LARGE
HAIL. HOWEVER...THE MODELS ARE HAVING DIFFICULTY RESOLVING SHORTWAVE
FEATURES AND MUCH UNCERTAINTY EXISTS CONCERNING STORM COVERAGE. HAVE
ADDED A SLIGHT RISK FROM NEAR LUBBOCK NEWD TO THE OKLAHOMA CITY AREA
WHERE THE GFS SHOWS A THE DEVELOPMENT OF A THUNDERSTORM COMPLEX
MONDAY EVENING.

..BROYLES.. 05/26/2012

[Nicko999]

2 tornadoes confirmed in Quebec, north of Montreal... one F1 and the other F0.

Quebec tornadoes cause millions in damage

Environment Canada has confirmed that two tornadoes — one of which was classed as a moderate F-1 packing winds of up to 150 km/h — touched down near Montreal Friday night, causing millions of dollars in damage.

http://www.cbc.ca/news/canada/montreal/ ... rando.html

There was also a teenager in Ottawa who died after being hit by lightning.

[cycloneye]

Moderate Risk for Wednesday/Thursday

I think a thread for this will be needed.

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT TUE MAY 29 2012

VALID 301200Z - 311200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS SOUTHERN KS AND PORTIONS
OF OK...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CENTRAL/SOUTHERN
PLAINS TO OZARKS/ARKLATEX...

...CENTRAL/SOUTHERN PLAINS TO OZARKS/ARKLATEX...
WHILE A DEGREE OF GUIDANCE VARIABILITY REMAINS EMBEDDED SHORTWAVE
FEATURES...00Z-BASED NUMERICAL GUIDANCE REFLECT A QUICK
AMPLIFICATION OF THE LARGE SCALE PATTERN OVER THE PLAINS ON
WEDNESDAY...AS A SHORTWAVE TROUGH CURRENTLY OVER THE PACIFIC
NORTHWEST/WESTERN CANADA AMPLIFIES/SPREADS SOUTHEASTWARD TOWARD THE
PLAINS. IN THE LOW LEVELS...A MOIST/POTENTIALLY UNSTABLE AIRMASS
WILL BE IN PLACE TO THE EAST OF 1/ A SURFACE LOW ACROSS THE TX SOUTH
PLAINS/NORTHWEST TX AND 2/ A SOUTH-TO-NORTH EXTENDING SURFACE TROUGH
ACROSS THE CENTRAL HIGH PLAINS...AND OTHERWISE IN VICINITY OF A
STALLED BOUNDARY ACROSS OK/KS.

AS THE AFOREMENTIONED SHORTWAVE TROUGH APPROACHES/HEIGHT FALLS
OCCUR...CURRENT THINKING IS THE MOST PROBABLE AREA FOR INITIAL
SURFACE BASED DEEP CONVECTIVE DEVELOPMENT DURING THE AFTERNOON WILL
BE ACROSS WESTERN KS/SOUTHWEST NEB...AND EVENTUALLY SOUTHERN KS AND
WESTERN/NORTHERN OK BY LATE AFTERNOON/EVENING. GIVEN GRADUALLY
STRENGTHENING WESTERLIES WITH HEIGHT AND THE POTENTIAL FOR STRONG
DESTABILIZATION /3000+ J PER KG MLCAPE ESPECIALLY ACROSS OK INTO
SOUTHERN KS/...SUPERCELLS CAPABLE OF VERY LARGE HAIL/PERHAPS A FEW
TORNADOES WILL BE POSSIBLE...ESPECIALLY WITHIN THE FIRST SEVERAL
HOURS OF TSTM INITIATION. THAT SAID...CURRENT THINKING IS THAT THE
OVERALL TORNADO POTENTIAL WILL BE TEMPERED BY INITIALLY WEAK LOW
LEVEL FLOW AND/OR BY CONVECTIVE MODE AFTER DARK. A SUBSEQUENT
UPSCALE GROWTH/EVOLUTION OF ONE OR MORE EAST-SOUTHEASTWARD MOVING
MCS/S SEEMS LIKELY TO OCCUR...PERHAPS AS EARLY AS LATE AFTERNOON
ACROSS WESTERN/CENTRAL KS...AND OTHERWISE DURING THE EVENING HOURS
ACROSS OK/ADJACENT NORTH TX/EVENTUALLY AR WITH DAMAGING WINDS
/POSSIBLY WIDESPREAD/ A DISTINCT POSSIBILITY THROUGH THE
EVENING/PERHAPS OVERNIGHT.

...LOWER MS RIVER VALLEY/SOUTHEAST STATES...
ISOLATED TO SCATTERED TSTMS SHOULD DIURNALLY INCREASE/MATURE
WEDNESDAY AFTERNOON ALONG/SOUTH OF A SLOW MOVING FRONT. VERTICAL
SHEAR WILL NOT BE STRONG...BUT SUFFICIENT MOISTURE/INSTABILITY WILL
EXIST FOR PULSE-TYPE STORMS/SOME MULTICELLS CAPABLE OF
DOWNBURSTS/MARGINALLY SEVERE HAIL MAINLY WEDNESDAY AFTERNOON/EARLY
EVENING.

...NORTHEAST/MID-ATLANTIC STATES TO CAROLINAS...
A FEW STRONG/SEVERE TSTMS MAY BE POSSIBLE ON WEDNESDAY ACROSS THE
REGION ALONG/SOUTH OF A WEAKENING FRONTAL BOUNDARY...ALTHOUGH SUCH
POTENTIAL WILL BE TEMPERED BY WEAK LAPSE RATES ALOFT/MODEST OVERALL
BUOYANCY. GIVEN THESE LIMITATIONS...AND UNCERTAIN TIMING OF THE
EAST-SOUTHEASTWARD ADVANCING COLD FRONT AS WELL AS POSSIBLE
WESTERN-PERIPHERAL/SUBSIDENT INFLUENCES OF REMNANT BERYL...WILL NOT
INCLUDE LOW PROBABILITIES FOR SEVERE TSTMS AT THIS TIME.

..GUYER.. 05/29/2012

[cycloneye]

Updated Moderate Risk outlook for 5/30/12

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1151 AM CDT TUE MAY 29 2012

VALID 301200Z - 311200Z

...THERE IS A MDT RISK OF SVR TSTMS FROM PORTIONS OF SCNTRL KS
ACROSS A GOOD PORTION OF OK...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK REGION
FROM SWRN NEB TOWARD THE ARKLATEX...

...CNTRL/SRN PLAINS...

NWLY FLOW IS EXPECTED TO GRADUALLY INTENSIFY ACROSS THE PLAINS BY
LATE AFTERNOON WITH SRN CURRENT OF SPLIT FLOW REGIME EXPECTED TO BE
SUPPRESSED TOWARD THE U.S./MEXICAN BORDER AS BROAD HEIGHT FALLS ARE
EXPECTED. BOTH THE NAM AND GFS SUGGEST A WEAK SHORT-WAVE TROUGH
WILL EJECT ACROSS THE SRN ROCKIES INTO THE HIGH PLAINS AROUND
18Z...WITH FAVORABLE LATE AFTERNOON TIMING FOR CONVECTIVE SUPPORT
ACROSS KS/OK. LARGE SCALE PARAMETERS APPEAR TO BE COMING TOGETHER
FOR MULTIPLE SEVERE TSTM CLUSTERS THAT SHOULD EVOLVE INTO A LARGE
MCS DURING THE OVERNIGHT HOURS ACROSS OK.

EARLY MORNING CONVECTION WILL LIKELY BE ONGOING ALONG THE NRN-ERN
PLUME OF EML FROM PORTIONS OF KS INTO ERN OK. THIS ACTIVITY SHOULD
BE ELEVATED IN NATURE BUT WILL LIKELY CONTRIBUTE TO COOLER ELY LOW
LEVEL COMPONENT AND POSSIBLE WELL DEFINED OUTFLOW BOUNDARY THAT MAY
BIFURCATE THE OUTLOOK AREA. WHILE IT/S NOT ENTIRELY CLEAR HOW FAR
WEST STABILIZATION WILL BE OBSERVED...IT APPEARS THE LACK OF
MEANINGFUL CONVECTIVE OVERTURNING UPSTREAM ACROSS NWRN TX WILL ALLOW
FOR UNOBSTRUCTED MOISTURE INFLOW ALONG/JUST EAST OF THE DRYLINE
ACROSS THE HIGH PLAINS THROUGH WRN OK INTO SWRN KS. THIS WILL BE
THE FOCUS FOR AFTERNOON INITIATION AS STRONG HEATING WILL PROVE MORE
THAN ADEQUATE FOR THUNDERSTORM DEVELOPMENT...ESPECIALLY GIVEN THE
APPROACHING SHORT-WAVE TROUGH. BOUNDARY LAYER MOISTURE SHOULD BE
HIGHER THAN THE NAM INDICATES ALONG THE DRYLINE AND AN AXIS OF
MODERATE INSTABILITY SHOULD CONTRIBUTE TO POTENTIALLY INTENSE
UPDRAFTS THAT WILL BE PARTIAL TO STORM ROTATION AND ORGANIZATION.
FOR THIS REASON SUPERCELLS SHOULD EVOLVE WITHIN AN ENVIRONMENT
CONDUCIVE FOR VERY LARGE HAIL. WHILE IT/S NOT OUT OF THE QUESTION
THAT A FEW TORNADOES COULD BE NOTED WITH EARLY SUPERCELL
STRUCTURES...LARGE HAIL...AND WITH TIME DAMAGING WINDS...ARE THE
PRIMARY SEVERE THREATS AS ONE OR MORE MCS TYPE STRUCTURES
SPREAD/DEVELOP SEWD ACROSS THE MDT RISK INTO THE EVENING HOURS.


..DARROW.. 05/29/2012

[Nicko999]

INSANE T-STORMS this afternoon. There was once again TORNADO WARNINGS in extreme Southern Quebec.

It was absolutely pouring...



[youtube]http://www.youtube.com/watch?v=q9hopcrEf0U[/youtube]

[youtube]http://www.youtube.com/watch?v=O03rZG0lyKg&feature=related[/youtube]

we also had a big one this morning... it did wake me up at 5AM.

[cycloneye]

Moderate Risk for Today

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1253 AM CDT WED MAY 30 2012

VALID 301200Z - 311200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS WRN AND CENTRAL OK/N TX
AND A SMALL PORTION OF SRN KS...

...THERE IS A SLGT RISK OF SVR TSTMS EXTENDING FROM PARTS OF WRN NEB
SWD INTO N TX/SWRN MO/WRN AR...

...SYNOPSIS...
BROAD/WEAK TROUGHING OVER THE ERN U.S. IS FORECAST TO BECOME
REINFORCED ON ITS WRN FRINGE AS SHORT-WAVE TROUGHING MOVES OUT OF
THE ROCKIES AND INTO THE CENTRAL U.S. THROUGH THE PERIOD.

AT THE SURFACE...DEPARTING T.D. BERYL IS PROGGED TO BE SHIFTING OFF
THE SERN U.S. COAST EARLY...LEAVING A WEAK WIND SHIFT/CONVERGENCE
AXIS IN ITS WAKE -- EXTENDING WWD ALONG THE GULF COAST REGION.
MEANWHILE...LOW PRESSURE IS FORECAST TO REMAIN INVOF NWRN TX DURING
THE DAY...WITH A COMBINATION FRONT/OUTFLOW EXTENDING EWD ACROSS THE
OK VICINITY AND A DRYLINE EXTENDING SWD. THESE TWO BOUNDARIES IN
THE OK/TX VICINITY AND THE WIND SHIFT ACROSS THE GULF COAST REGION
SHOULD SERVE AS THE PRIMARY CONVECTIVE FOCI THIS PERIOD.

...PARTS OF THE CENTRAL AND SRN PLAINS REGION...
ANOTHER DAY OF SUBSTANTIAL SEVERE WEATHER POTENTIAL IS EXPECTED
ACROSS THE OK/TX VICINITY...WITH SOME THREAT EXTENDING NWWD INTO THE
CENTRAL HIGH PLAINS REGION. ACROSS THE SRN
PLAINS...HEATING/DESTABILIZATION IS FORECAST IN THE WAKE OF
OVERNIGHT CONVECTION -- AND AN ASSOCIATED OUTFLOW BOUNDARY WHICH
SHOULD BE RETREATING NWD ACROSS THE RED RIVER VALLEY/SRN OK DURING
THE DAY. BY MID TO LATE AFTERNOON...THIS BOUNDARY -- EXPECTED TO
RESIDE ACROSS CENTRAL OR NRN OK...AND A DRYLINE MIXING EWD ACROSS
THE TX PANHANDLE/NWRN TX TOWARD WRN OK...WILL LIKELY FOCUS UPDRAFT
INITIATION -- AIDED BY THE A SUBTLE FEATURE ALOFT WHICH SHOULD BE
SHIFTING INTO THE SRN HIGH PLAINS.

WITH VERY STEEP MID-LEVEL LAPSE RATES BEING CONTINUALLY SUPPLIED BY
WLY FLOW ALOFT -- SPREADING ATOP A MOIST/HEATING BOUNDARY
LAYER...STRONG DESTABILIZATION WILL OCCUR...WITH AFTERNOON CAPE
VALUES OVER WRN OK AND VICINITY FORECAST TO EXCEED 4000 J/KG
MIXED-LAYER CAPE. THIS THERMODYNAMIC ENVIRONMENT WILL ALLOW
EXPLOSIVE CONVECTIVE GROWTH ONCE STORMS INITIATE...FURTHER AIDED BY
DEEP-LAYER SHEAR SUPPORTIVE OF UPDRAFT ROTATION. ISOLATED STORMS
DEVELOPING ACROSS WRN OK AND VICINITY WILL LIKELY PRODUCE VERY
LARGE/DAMAGING HAIL...AND WILL ALSO BE CAPABLE OF PRODUCING DAMAGING
WINDS. WHILE SOMEWHAT WEAK LOW-LEVEL FLOW MAY LIMIT TORNADO
POTENTIAL IN MOST AREAS...ENHANCED SHEAR NEAR/N OF THE SURFACE
FRONT/REMNANT OUTFLOW MAY SUPPORT A ZONE OF SLIGHTLY HIGHER TORNADO
PROBABILITY.

MORE ISOLATED STORMS MAY ALSO DEVELOP NWWD ACROSS THE CENTRAL HIGH
PLAINS REGION...WHERE LESSER -- BUT SUFFICIENT -- INSTABILITY WILL
SUPPORT SOME HAIL/WIND POTENTIAL.

AS STORMS INCREASE IN COVERAGE ACROSS OK AND VICINITY...COLLIDING
STORM OUTFLOWS COMBINED WITH THE DEGREE OF INSTABILITY SUGGEST THAT
STORM CLUSTERING/UPSCALE GROWTH IS LIKELY INTO THE EVENING. ALONG
WITH VERY LARGE HAIL AND ISOLATED TORNADO POTENTIAL WITH ROTATING
CELLS...WIND POTENTIAL SHOULD INCREASE -- WITH STORMS EVENTUALLY
FORECAST TO SHIFT EWD ACROSS OK/N TX LIKELY IN THE FORM OF ONE OR
MORE MCS/S.

...THE GULF COAST REGION FROM LA EWD TO SRN GA/FL...
AFTERNOON DESTABILIZATION INVOF THE WEAK W-E SURFACE BOUNDARY/WIND
SHIFT IN THE WAKE OF BERYL SHOULD FOCUS ISOLATED TO SCATTERED
AFTERNOON CONVECTIVE DEVELOPMENT. GENERALLY WEAK SHEAR SUGGESTS
DISORGANIZED/PULSE STORMS...BUT DEGREE OF INSTABILITY IN SOME AREAS
COULD SUPPORT BRIEF GUSTY WINDS AND MARGINAL HAIL.

..GOSS/MOSIER.. 05/30/2012

[CrazyC83]

MAJOR derecho possible. Biggest threat is extreme damaging winds but some tornadoes also possible.

[cycloneye]

The 11:30 AM CDT update:

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT WED MAY 30 2012

VALID 301630Z - 311200Z

...THERE IS A MDT RISK OF SVR TSTMS FROM SRN KS INTO WRN AND CENTRAL
OK...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM
THE CENTRAL/SRN PLAINS INTO THE LOWER MS VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS OVER ERN NC...

...SRN KS INTO WRN/CENTRAL OK...
COMPLEX MESOSCALE PATTERN IS PRESENT THIS MORNING ASSOCIATED WITH
THE EFFECTS OF NOCTURNAL AND MORNING CONVECTION OVER OK INTO
TX...WITH MULTIPLE OUTFLOW BOUNDARIES EVIDENT IN SURFACE AND
SATELLITE DATA OVER TX. NORTH OF THE BOUNDARIES...SELY SURFACE
WINDS FROM NWRN TX INTO SWRN/SOUTH CENTRAL KS WILL ALLOW MOISTURE TO
INCREASE NWD THIS AFTERNOON...WITH ELEVATED MOISTURE EXTENDING
FARTHER NORTH INTO PARTS OF SRN NEB. A SURFACE LOW OVER THE SOUTH
PLAINS OF WEST TX IS EXPECTED TO PERSIST OVER THE AREA ENHANCED BY
STRONG HEATING THIS AFTERNOON.

12Z REGIONAL RAOBS INDICATE VERY STEEP MID LEVEL LAPSE RATES OVER
THE HIGH PLAINS ASSOCIATED WITH THE ERN EDGE OF THE EML. AS CLOUDS
DIMINISH EAST OF A N/S SURFACE TROUGH FROM EXTREME ERN CO SWD INTO
WEST TX...STRONG DIABATIC HEATING AND INCREASING LOW LEVEL MOISTURE
WILL CONTRIBUTE TO FURTHER DESTABILIZATION WITH MLCAPE REACHING
2500-3500 J/KG...WHILE GRADUALLY REDUCING THE CAP STRENGTH. THIS
PROCESS WILL BE AIDED BY WEAK LARGE SCALE ASCENT ASSOCIATED WITH A
SUBTLE SHORT WAVE TROUGH MOVING EWD FROM THE CENTRAL/SRN ROCKIES.

DESPITE SOME VARIABILITY IN MODEL PREDICTIONS OF
CONVECTION...GENERAL CONSENSUS INDICATES STORMS WILL DEVELOP BY
MID/LATE AFTERNOON OVER PARTS OF WRN/CENTRAL KS AND WRN
OK...POSSIBLY EXTENDING AS FAR SOUTH AS NWRN TX. WIND PROFILES
EXHIBIT STRONG VEERING WITH HEIGHT FROM SSELY IN THE LOW LEVELS TO
WESTERLY IN THE MID LEVELS...PROVIDING A FAVORABLE ENVIRONMENT FOR
SUPERCELL STORMS. STRONGER CELLS WILL BE CAPABLE OF PRODUCING VERY
LARGE HAIL...DAMAGING WIND GUSTS...AND POSSIBLY SEVERAL TORNADOES.
THE ACTIVITY MAY GROW UPSCALE INTO ONE OR MORE BOWING MCS/S BY THIS
EVENING AS STORMS SPREAD EWD/SEWD...WITH AN INCREASING THREAT OF
MORE WIDESPREAD DAMAGING WINDS ALONG THE LEADING EDGE OF THE MCS/S.

...SOUTH CENTRAL NEB INTO NRN KS...
ELEVATED STORMS OVER SOUTH CENTRAL NEB HAVE DEVELOPED IN ASSOCIATION
WITH LOW LEVEL WARM ADVECTION AND A MID LEVEL SHORT WAVE TROUGH
MOVING EWD INTO THE HIGH PLAINS. HAIL WILL BE THE MOST LIKELY
THREAT FROM THESE STORMS /SEE MESOSCALE DISCUSSION 977 FOR MORE
DETAILS./

...ERN AR INTO SWRN TN/WRN MS NERN LA...
A BAND OF STORMS HAS BEEN PROGRESSING SLOWLY EWD INTO ERN AR AHEAD
OF A WEAK SHORT WAVE TROUGH FROM SRN MO INTO WRN AR. LOW LEVEL
HEATING IN THE ENVIRONMENT IMMEDIATELY DOWNSTREAM FROM THE
CONVECTIVE BAND WILL RESULT IN DESTABILIZATION WITH MUCAPE OF
1500-2500 J/KG THIS AFTERNOON. THERE WILL BE POTENTIAL FOR STRONGER
CELLS TO PRODUCE WET MICROBURSTS AND LARGE HAIL THIS AFTERNOON.

...ERN NC...
THE WIND PROFILE FROM KMHX SHOWS STRONG LOW LEVEL SHEAR IN THE RIGHT
FRONT QUADRANT OF THE REMNANTS OF BERYL...AND SEVERAL TRANSIENT
ROTATIONAL COUPLETS HAVE BEEN INDICATED WHERE CG LIGHTING HAS
INCREASED. POTENTIAL WILL CONTINUE FOR AN ADDITIONAL BRIEF TORNADO
OR TWO ALONG COASTAL SECTIONS THIS AFTERNOON...AND A 5% TORNADO AREA
/SLGT RISK/ HAS BEEN INCLUDED.

..WEISS/HURLBUT.. 05/30/2012