Possible Severe Weather May 11

[GCANE]

Mid afternoon Wednesday in mid OK looks pretty good.

[GCANE]

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0330 AM CDT SUN MAY 08 2011

VALID 111200Z - 161200Z

...DISCUSSION...
SRN PORTIONS OF THE WRN STATES UPPER TROUGH WILL BE IN THE PROCESS
OF EJECTING ENE FROM THE SRN ROCKIES INTO THE CNTRL/SRN PLAINS BY
TUESDAY NIGHT AND WEDNESDAY /DAY 4/. 00Z ECMWF SOLUTION IS
PREFERRED IN MAINTAINING STRONGER HEIGHT FALLS/JET AS IT MOVES INTO
KS/OK/W TX WITH TRIPLE POINT LIKELY EVOLVING OVER SW KS WEDNESDAY
AFTN. MAGNITUDE OF FORCING...COOLING MID-LEVEL TEMPS AND 50-60 KTS
OF SWLY MID-LEVEL FLOW ASSOCIATED WITH THE TROUGH SHOULD LEAD TO
ORGANIZED SEVERE STORMS FROM KS/NEB BORDER SWD INTO NRN TX. THESE
STORMS WILL THEN TRANSLATE ENE TOWARD SE NEB...ERN PARTS OF KS/OK
AND NCNTRL TX WEDNESDAY NIGHT. AT THIS POINT...DAY 4 APPEARS TO BE
SETTING UP FOR AN ACTIVE SEVERE EVENT WITH ALL FACETS OF SEVERE
WEATHER POSSIBLE.

BEYOND WEDNESDAY...MODEL SPREAD INCREASES FURTHER WITH EVOLUTION OF
A POSSIBLE CUT-OFF LOW OVER THE MIDWEST/GREAT LAKES REGION. EXACT
EVOLUTION OF THIS SCENARIO IS NOT CLEAR AND PRECLUDES MENTION OF
SEVERE WEATHER AREAS THROUGH THE REMAINDER OF THE WEEK.

..RACY.. 05/08/2011

[monicaei]

So is this a severe weather event, with a heavy rainfall? Or a "blow by" with little rainfall? Not to minimize the affect of the system, but will it dump a lot of water into an already saturated watershed?

[GCANE]

DAY 3 CONVECTIVE OUTLOOK RESENT 1
NWS STORM PREDICTION CENTER NORMAN OK
0310 AM CDT MON MAY 09 2011

VALID 111200Z - 121200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER A LARGE PORTION OF THE
PLAINS AND UPPER MS VLY/MIDWEST...

...CNTRL/SRN PLAINS...
AN ACTIVE WEATHER WEDNESDAY IS EXPECTED AS PRIMARY PORTION OF THE
WRN STATES UPPER TROUGH BEGINS TO EJECT AS A NEGATIVE-TILT ENTITY
INTO THE CNTRL/SRN PLAINS. ACCOMPANYING LEE LOW WILL DEVELOP FROM
SE CO INTO NCNTRL KS DURING THE AFTN AS THE DRYLINE MIXES EWD INTO
CNTRL KS...WRN OK AND ERN EDWARDS PLATEAU IN TX. 60S SFC DEW POINTS
AND 7-8.5 DEG C/KM MID-LEVEL LAPSE RATES WILL CONTRIBUTE TO VERY
UNSTABLE CONDITIONS FROM CNTRL TX NWD TO THE NCNTRL KS/SCNTRL NEB
BORDER.

THERE ARE SOME MODELS THAT SUGGEST THAT A LEAD SUB-TROPICAL IMPULSE
MAY AID IN THE INITIATION OF TSTMS ACROSS NCNTRL TX INTO SERN OK
DURING THE EARLY-MID AFTN...BUT CONFIDENCE IS LOW AT THIS TIME AS IT
IS UNCLEAR ON EXACTLY WHAT INITIATING BOUNDARY MAY PLAY A ROLE IN
THIS INITIATION. THIS POSSIBILITY WILL HAVE TO BE CONSIDERED AND
WAS INCLUDED IN 15% SVR PROBS SINCE VERTICAL SHEAR/BUOYANCY WILL BE
SUFFICIENT FOR ORGANIZED STORMS.

MEANWHILE...AS MID-LEVEL COOLING AND ASCENT TIED TO THE TROUGH
SPREADS ACROSS THE HIGH PLAINS...COMBINATION OF HEATING AND ERODING
CAP WILL LEAD TO TSTM INITIATION NEAR TRIPLE POINT OVER NWRN/CNTRL
KS SWD ALONG THE DRYLINE INTO CNTRL TX BY MID-LATE AFTN. SUPERCELLS
WILL BE LIKELY WITH VERY LARGE HAIL...TORNADOES AND DMGG WINDS.
STRONGER ASCENT WILL SPREAD ENE ACROSS KS/NEB AND TOWARD IA/NW MO
WEDNESDAY NIGHT AND LIKELY SUPPORT ONE OR MORE CLUSTERS OF
STRONG/SVR STORMS. ADDITIONAL LONGER-LIVED TSTMS WILL LIKELY EXIST
THROUGH MOST OF THE NIGHT ACROSS PARTS OF CNTRL/NRN TX WITH SIMILAR
THREATS FOR HAIL AND HIGH WINDS.

...CORN BELT/UPPER MIDWEST...
A BRANCH OF THE SWLY LLJ WILL CONTINUE TO ENHANCE LOW/MID-LEVEL WARM
ADVECTION ALONG SRN PERIPHERY OF AN EJECTING IMPULSE OVER NWRN
ONTARIO ON WEDNESDAY. ELEVATED CLUSTERS OF STORMS MAY ALREADY BE
ONGOING EARLY IN THE DAY OVER PARTS OF THE UPPER GREAT LAKES. WRN
PERIPHERY OF THESE STORMS MAY CONTINUE TO THRIVE ALONG EDGE OF THE
CAP ACROSS PARTS OF THE UPPER MS VALLEY AND UPPER MIDWEST THROUGH
THE DAY...BUT OVERALL CONFIDENCE IS LOW. THERE WILL LIKELY BE AMPLE
INSTABILITY IN PLACE TO SUPPORT ORGANIZED SEVERE STORMS...ALTHOUGH
VERTICAL SHEAR MAY BE LACKING AS REGION BECOMES SANDWICHED BETWEEN
THE DEPARTING ONTARIO IMPULSE AND UPPER LOW EJECTING INTO THE
CNTRL/SRN HIGH PLAINS.

..RACY.. 05/09/2011

[GCANE]

[GCANE]

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1257 AM CDT MON MAY 09 2011

VALID 101200Z - 111200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE OH VLY TO THE SE
ATLANTIC COAST...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE NRN
PLAINS/UPPER MS VLY...

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

...MIDWEST TO THE SE ATLANTIC COAST...
MODELS HAVE BEEN MAINTAINING A CONSISTENT MESSAGE IN MAINTAINING A
RIDGE-TOPPING... CONVECTIVELY-INDUCED IMPULSE /CURRENT MCS OVER ERN
DAKOTAS/ SEWD INTO THE OH VLY BY 12Z TUE AND INTO THE SRN
APPALACHIANS AND SERN COASTAL STATES DURING TUESDAY PEAK HEATING.
THIS WILL AUGMENT AN ALREADY ENHANCED BELT OF WNW FLOW ALOFT /H5 40+
KTS/. TSTMS WILL READILY FORM ALONG FRINGE OF THE EML/FRONT AS
HEATING AND LARGE-SCALE SUPPORT SPREADS SEWD TUESDAY AFTN WITH
THREATS FOR ORGANIZED MULTICELL STORMS AND ISOLD SUPERCELLS. DMGG
WIND GUSTS...LARGE HAIL AND POSSIBLY A COUPLE TORNADOES CAN BE
EXPECTED...PARTICULARLY FROM UPSTATE SC/WRN NC TO THE COASTAL
PLAINS.

...NRN PLAINS/UPPER MS VLY...
STRONG MID-LEVEL WAVE...CURRENTLY ROUNDING BASE OF THE WRN STATES
UPR TROUGH...WILL TRANSLATE INTO THE NRN PLAINS BY TUESDAY AFTN.
ATTENDANT SFC LOW WILL TRAVEL NWD FROM NCNTRL SD AT 12Z TUE TO NERN
ND BY EVENING AND INTO SRN MANITOBA OVERNIGHT. DRYLINE/FRONT WILL
ADVANCE NEWD THROUGH ERN ND AND CNTRL/NRN MN TUESDAY AFTN AND MAY BE
FOCUS FOR A FEW SEVERE TSTMS.

WEDGE OF UPR 50S-MID 60S DEW POINTS WILL ADVECT WNW AHEAD OF THE
FRONT TO THE SFC LOW AND CONTRIBUTE TO MLCAPES OF 1500+ J/KG. VERY
STRONG EML SHOULD DECREASE PROBABILITIES FOR SFC-BASED STORMS WITH
SWD EXTENT ALONG THE SURGING FRONT...BUT AS LARGER-SCALE HEIGHT
FALLS/COOLING TEMPERATURES ALOFT GRAZE ERN ND AND CNTRL/NRN
MN...TSTMS MAY FORM. SUPERCELLULAR WIND PROFILES WILL EXIST WITH
THREATS FOR LARGE HAIL AND POSSIBLY TORNADOES. LOW-CONFIDENCE IN
EXTENT OF CONVECTIVE INITIATION WILL PRECLUDE HIGHER PROBABILITIES
AT THIS TIME. WHAT ACTIVITY DOES FORM WILL BEGIN TO ENCOUNTER
COOLER ELY FLOW OFF LAKE SUPERIOR OVER NERN MN WITH TIME TUESDAY
EVENING AND DECREASE TORNADO THREATS. BUT...SUFFICIENT ELEVATED
INSTABILITY WILL EXIST FOR AT LEAST ISOLD LARGE HAIL AS STORMS
DEVELOP ESE TOWARD PARTS OF WI AND UPPER MI TUESDAY NIGHT.

...ERN PARTS OF CNTRL/SRN PLAINS...
REGION WILL REMAIN IN SUSTAINED SLY LOW-LEVEL FLOW THAT WILL
MAINTAIN RELATIVELY RICH BOUNDARY LAYER MOISTURE /SFC DEW POINTS IN
THE 60S/ THROUGH TUESDAY. THIS MOISTURE WILL BE TOPPED BY A STRONG
EML THAT WILL RESULT IN A STRONG CAP...BUT POTENTIALLY VERY STRONG
INSTABILITY GIVEN 8+ DEG C/KM H5-H7 LAPSE RATES.

SECONDARY MID-LEVEL WAVE...EXPECTED TO BEGIN AN ENE TREK TO THE SRN
ROCKIES BY TUESDAY AFTN...WILL RESULT IN WEAKLY DIFLUENT UPR FLOW
REGIME ACROSS THE DRYLINE DURING THE AFTN/EVE. ALTHOUGH STORM
INITIATION CANNOT BE RULED OUT FROM NRN OK INTO CNTRL/ERN
KS...HIGHER PROBABILITIES WILL EXIST FROM CNTRL/SWRN OK INTO THE ERN
EDWARDS PLATEAU OF TX WHERE HOTTEST BOUNDARY LAYER TEMPERATURES
SHOULD EXIST. WIND PROFILES CONSISTING OF VERTICAL SHEAR OF 45-50
KTS...AND THE MAGNITUDE OF LAPSE RATES WILL YIELD SUPERCELLS WITH
LARGE HAIL AND PERHAPS ISOLD TORNADOES/DMGG WIND GUSTS DURING THE
EVENING. ACTIVITY MAY PERSIST INTO LATE EVENING ACROSS ERN OK TO
CNTRL TX WITH AT LEAST ISOLD LARGE HAIL.

MEANWHILE...WRN FRINGES OF EVENING MOISTURE SURGE MAY IGNITE INTO
TSTMS VERY LATE IN THE PERIOD AS THE UPPER TROUGH EDGES TO THE SRN
HIGH PLAINS. THESE STORMS MAY PRODUCE ISOLD LARGE HAIL FROM THE TX
S PLAINS INTO THE TRANS-PECOS REGION OF SW TX.

..RACY.. 05/09/2011

[RL3AO]

Some insane cape values over MN/IA/IL/WI. RUC shows 7000+ over parts of Minnesota later.

Thankfully the cap will be pretty strong and there isn't a ton of wind shear.

[vbhoutex]

Some insane cape values over MN/IA/IL/WI. RUC shows 7000+ over parts of Minnesota later.

Thankfully the cap will be pretty strong and there isn't a ton of wind shear.

I've seen some discussion on FB about those outrageous cape numbers. Most are saying that the RUC has always overdone cape values. What do you think? That seems crazy high to me.

BTW, love your signature.

[RL3AO]

I don't think so. MSP was already at 5000 at 12z. Very impressive lapse rates. If something does go, there could be some big hail.

[Bunkertor]

How come that the moisture does make it thus far north ?

[OverlandHurricane]

I just got home from umpiring a ballgame northwest of MSP. I think we'll be capped out until after nightfall (there wasn't a cloud in the sky within eyeshot on the way home). But after nightfall, with a 70 degree dew point, look out!

[RL3AO]

How come that the moisture does make it thus far north ?

Central part of the US is so flat the topography doesn't stop it. If you have a strong southerly wind, it will carry those high dewpoints very far north.

[OverlandHurricane]

OK, I'll take my crow over easy on rye toast. It's going to be storming here in the next half-hour.

Minnesota really is the theater of seasons. To go from down coats, choppers, and stocking caps to tornado watches in eight days is nuts.

[RL3AO]

Really popped in the last 10 minutes.

[Bunkertor]

How come that the moisture does make it thus far north ?

Central part of the US is so flat the topography doesn't stop it. If you have a strong southerly wind, it will carry those high dewpoints very far north.

OK, i thought there was another factor. I mean dragging 4 or 5k Cape over 3000 km is massive.

[Stephanie]

OK, I'll take my crow over easy on rye toast. It's going to be storming here in the next half-hour.

Minnesota really is the theater of seasons. To go from down coats, choppers, and stocking caps to tornado watches in eight days is nuts.

Yes it is!

[GCANE]

MESOSCALE DISCUSSION 0729
NWS STORM PREDICTION CENTER NORMAN OK
0809 AM CDT WED MAY 11 2011

AREAS AFFECTED...PARTS OF NRN MO AND CENTRAL/ERN IA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 111309Z - 111415Z

A NEW WW MAY BE NEEDED THIS MORNING FROM PARTS OF NRN MO INTO
CENTRAL AND ERN IA FOR AN INCREASE IN TSTM DEVELOPMENT AND ATTENDANT
SEVERE WEATHER THREAT.

AT 13Z...WATER VAPOR IMAGERY SHOWED A PAIR OF MIDLEVEL IMPULSES...1/
OVER WRN IA AND 2/ TRACKING NWD THROUGH WRN MO EXPECTED TO TRACK
NEWD INTO THE UPPER MS VALLEY. UVVS WITH EACH OF THESE FEATURES AND
A MODERATELY-STRONGLY UNSTABLE AIR MASS ALREADY IN PLACE FROM MO TO
THE ERN HALF OF IA /PER 12Z SOUNDINGS/ SHOULD SUPPORT ADDITIONAL
TSTM DEVELOPMENT ACROSS THE DISCUSSION AREA. 40-50 KT SLY MIDLEVEL
WINDS FROM MO TO IA ARE RESULTING IN 40 KT EFFECTIVE BULK SHEAR FOR
STORM ORGANIZATION.

12Z SOUNDINGS SUGGEST THE ONGOING STORMS FROM NWRN MO INTO PARTS OF
WRN IA ARE LIKELY ELEVATED...THOUGH VISIBLE SATELLITE IMAGERY SHOWED
SURFACE HEATING WILL OCCUR ACROSS MUCH OF ERN IA WITH POCKETS OF
HEATING IN NERN MO. THIS SHOULD RESULT IN THE REDUCTION OF SBCINH
LATER THIS MORNING FOR SURFACE BASED DEVELOPMENT AND GREATER TSTM
COVERAGE.

..PETERS.. 05/11/2011

[GCANE]

MESOSCALE DISCUSSION 0730
NWS STORM PREDICTION CENTER NORMAN OK
0956 AM CDT WED MAY 11 2011

AREAS AFFECTED...CNTRL TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 111456Z - 111630Z

STORMS MAY UNDERGO SOME INTENSIFICATION AS THEY DEVELOP EWD THROUGH
CNTRL TX. INITIAL THREAT IS EXPECTED TO BE DAMAGING WIND AND LARGE
HAIL...THOUGH A COUPLE OF TORNADOES CANNOT BE RULED OUT. AREA IS
BEING MONITORED FOR A POSSIBLE WW.

THIS MORNING STORMS CONTINUE DEVELOPING FROM NE OF SANDERSON TO NEAR
ABILENE. THE ATMOSPHERE DOWNSTREAM IS MODERATELY UNSTABLE WITH STEEP
MID LEVEL LAPSE RATES. HOWEVER...THE BOUNDARY LAYER HAS NOT
UNDERGONE SIGNIFICANT DESTABILIZATION DUE TO TIME OF DAY AND SOME
CONVECTIVE INHIBITION PERSISTS. THE STORMS APPEAR TO BE DEVELOPING
WITHIN A ZONE OF PRE-FRONTAL CONVERGENCE FORCED BY AN EJECTING LEAD
SHORTWAVE TROUGH. THE LLJ WILL GRADUALLY VEER AND SHIFT EWD AS THE
IMPULSE CONTINUE NEWD THROUGH THE SRN/CNTRL PLAINS. THE STORMS WILL
REMAIN EMBEDDED WITHIN EFFECTIVE SHEAR /35-45 KT/ SUFFICIENT FOR
ORGANIZED STORMS WITH DAMAGING WIND AND LARGE HAIL EXPECTED TO BE
THE INITIAL PRIMARY THREATS.

..DIAL.. 05/11/2011

[Extratropical94]

SEVERE THUNDERSTORM WATCH NUMBER 278
NWS STORM PREDICTION CENTER NORMAN OK
1020 AM CDT WED MAY 11 2011

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

CENTRAL AND NORTH CENTRAL TEXAS

EFFECTIVE THIS WEDNESDAY MORNING AND EVENING FROM 1020 AM UNTIL
600 PM CDT.

HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 60
STATUTE MILES EAST AND WEST OF A LINE FROM 10 MILES WEST
NORTHWEST OF SHERMAN TEXAS TO 45 MILES SOUTHWEST OF JUNCTION
TEXAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 277...

DISCUSSION...STORMS ARE EXPECTED TO CONTINUE DEVELOPING WITHIN ZONE
OF PRE-FRONTAL CONVERGENCE THROUGH CNTRL AND NCNTRL TX WHERE THE
ATMOSPHERE IS MODERATELY UNSTABLE WITH STEEP LAPSE RATES. VERTICAL
SHEAR FROM 35-45 KT WILL SUPPORT ORGANIZED STORM STRUCTURES WITH
DAMAGING WIND AND LARGE HAIL THE MAIN THREATS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 24035.


SEVERE THUNDERSTORM WATCH NUMBER 279
NWS STORM PREDICTION CENTER NORMAN OK
1220 PM CDT WED MAY 11 2011

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

CENTRAL AND EASTERN KANSAS
SOUTHEAST NEBRASKA

EFFECTIVE THIS WEDNESDAY AFTERNOON FROM 1220 PM UNTIL 500 PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 95
STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES WEST
NORTHWEST OF COLUMBUS NEBRASKA TO 65 MILES SOUTHEAST OF WICHITA
KANSAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 278...

DISCUSSION...TSTMS EXPECTED TO INCREASE IN COVERAGE AND INTENSITY
ACROSS THE REGION AS UPPER DISTURBANCE AND STRONG WINDS ALOFT ACT ON
INCREASINGLY UNSTABLE AIR MASS. SHEAR WILL INCREASE COINCIDENT WITH
FORCING AND STORM DEVELOPMENT SO A TRANSITION FROM MULTICELLULAR
CONVECTION WITH SOME HAIL AND WIND POTENTIAL TO A SUPERCELL/LINE
SEGMENT CONVECTIVE CHARACTER IS ANTICIPATED WITH TIME.
FURTHERMORE...AS INCREASINGLY SUPPORTIVE CONDITIONS FOR TORNADOES
EVOLVE ALONG FRONTAL ZONE NEAR AND NORTH OF KS/NEB BORDER...SOME
AREAS WITHIN THIS WATCH MAY NEED TO BE PLACED INTO A TORNADO WATCH
LATER TODAY.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 23035.

[Bunkertor]

KS is jammed. Chaser-meeting.