Severe weather outbreak - June 12-13 - Midwest, Mid-Atlantic

[CrazyC83]

Moderate Risk today and tomorrow, about to become a HIGH RISK!

MESOSCALE DISCUSSION 1040
NWS STORM PREDICTION CENTER NORMAN OK
1026 AM CDT WED JUN 12 2013

AREAS AFFECTED...EXTREME ERN IA...NRN IL...NRN IND...NWRN OH

CONCERNING...OUTLOOK UPGRADE

VALID 121526Z - 121630Z

SUMMARY...THE 1630Z CONVECTIVE OUTLOOK WILL INCLUDE A CATEGORICAL
UPGRADE TO HIGH RISK FOR DAMAGING WIND POTENTIAL FROM EXTREME
EASTERN IOWA INTO NORTHERN PORTIONS OF ILLINOIS AND INDIANA...AND
NORTHWEST PORTIONS OF OHIO. IN ADDITION...TORNADO PROBABILITIES WILL
BE INCREASED TO 15 PERCENT OVER PORTIONS OF EXTREME EASTERN IOWA
INTO NORTHWEST ILLINOIS.

DISCUSSION...SVR TSTMS ARE EXPECTED TO DEVELOP THIS AFTERNOON IN THE
VICINITY OF EASTERN IOWA/NORTHWEST ILLINOIS AND QUICKLY BECOME
SEVERE SUPERCELLS WITH A RISK FOR TORNADOES...POSSIBLY
SIGNIFICANT...WITH UPSCALE GROWTH INTO A FAST-MOVING AND
FORWARD-PROPAGATING MESOSCALE CONVECTIVE SYSTEM. WIDESPREAD DAMAGING
WINDS ARE LIKELY ACROSS THE HIGH RISK AREA...WITH SOME SIGNIFICANT
SEVERE GUSTS POSSIBLE.

DETAILS WILL BE FORTHCOMING IN THE 1630Z CONVECTIVE OUTLOOK.

..BUNTING/CARBIN.. 06/12/2013


ATTN...WFO...ILN...IWX...IND...LOT...ILX...DVN...

LAT...LON 40428861 40538938 40979080 41469099 41919096 42269070
42459028 42358912 42388860 42298808 41728689 41638595
41678518 41698471 41658438 41248404 40608437 40348508
40288608 40328738 40428861

[WeatherGuesser]

1630Z, what is that, about 40 minutes out?

[CrazyC83]

1630Z, what is that, about 40 minutes out?

About 30-40 minutes from now.

[CrazyC83]

SPC AC 121626

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1126 AM CDT WED JUN 12 2013

VALID 121630Z - 131200Z

...THERE IS A HIGH RISK OF SVR TSTMS FROM EXTREME EASTERN IOWA
ACROSS NORTHERN ILLINOIS/INDIANA AND EXTREME SOUTHWEST LOWER
MICHIGAN AND NORTHWEST OHIO...

...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK AREA
FROM EASTERN IOWA TO WESTERN OHIO...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA
FROM THE CNTRL PLAINS/MIDWEST TO EAST COAST AND PARTS OF THE SRN
APPALACHIANS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER MUCH OF MT AND A PART OF
NERN WY...

...SYNOPSIS...
A SIGNIFICANT SEVERE WEATHER OUTBREAK APPEARS INCREASINGLY LIKELY
ACROSS PORTIONS OF THE UPPER MIDWEST/LOWER GREAT LAKES FROM THIS
AFTERNOON THROUGH THIS EVENING. INTENSE STORM DEVELOPMENT IN A VERY
UNSTABLE AIRMASS...COINCIDENT WITH A COMPACT AND INTENSIFYING
SURFACE LOW SHOULD RESULT IN NUMEROUS DAMAGING WIND EVENTS AS WELL
AS SCATTERED...POSSIBLY STRONG TORNADOES.

...ERN IA/NRN IL/NRN IND/NWRN OH AND ADJACENT AREAS OF EXTREME SRN
WI AND SWRN LOWER MI...

SIGNIFICANT SEVERE WEATHER INGREDIENTS HAVE CONGEALED AHEAD OF A
COMPACT AND PROGRESSIVE MID/UPPER TROUGH AND ASSOCIATED 50-60KT MID
LEVEL WLY FLOW CURRENTLY TRACKING EAST FROM THE NRN/CNTRL PLAINS. AN
EXPANSIVE WARM/MOIST SECTOR EXISTS AHEAD OF THE UPPER FORCING AND
DEVELOPING SURFACE CYCLONE WITH 2M DEWPOINTS WELL INTO THE 60S AND
LOWER 70S F AND PW VALUES IN EXCESS OF 1.25 INCHES ACROSS MUCH OF
THE MIDWEST FROM IA EAST ACROSS IL/IND/OH. MORNING SOUNDINGS ACROSS
THIS SAME REGION INDICATE A PRONOUNCED EML ADVECTING EAST FROM THE
SRN HIGH PLAINS WITH 700-500MB LAPSE RATES APPROACHING 9C/KM.

DESPITE RELATIVELY STRONG CAPPING ACROSS THE WARM SECTOR...DEGREE OF
HEATING AND LARGE SCALE ASCENT AIDING SURFACE CYCLONE
INTENSIFICATION ACROSS ERN IA BY LATE AFTERNOON WILL PROVE ADEQUATE
FOR SURFACE-BASED STORM INITIATION. ADDITIONAL NEAR-SURFACE-BASED
DEEP CONVECTION WITH BOTH HAIL AND WIND POTENTIAL MAY PRECEDE TRULY
SURFACE-BASED STORMS TO THE NORTH OF THE SURFACE LOW AND
QUASI-STATIONARY FRONT SITUATED FROM NERN IA ACROSS SRN WI TO LOWER
MI. GIVEN DEGREE OF CAPPING AND MAGNITUDE OF INSTABILITY...EXPECT
POTENTIALLY EXPLOSIVE STORM DEVELOPMENT TO OCCUR IN THE PRESENCE OF
MODEST TO LOCALLY STRONG STORM-RELATIVELY HELICITY /SRH/. ANY
CONVECTION INITIATING NEAR THE SURFACE LOW AND FRONT WILL QUICKLY
ACQUIRE SUPERCELL CHARACTERISTICS GIVEN DEGREE OF EFFECTIVE VERTICAL
SHEAR OF 35-55KT. POTENTIALLY STRONG TORNADO THREAT MAY BE MAXIMIZED
DURING THIS EARLY DEVELOPMENT PHASE /21Z-00Z/ NEAR THE LOW AND FRONT
WHILE STORMS REMAIN DISCRETE AMIDST HIGH INSTABILITY AND EFFECTIVE
SRH IN EXCESS OF 200 M2/S2.

ORGANIZING INFLUENCE OF THE DEEPENING SURFACE CYCLONE RIPPLING EAST
ALONG THE WARM/QUASI-STATIONARY FRONT...IN CONCERT WITH 50-60KT
MID-LEVEL JET STREAK DIRECTED PREFERENTIALLY INTO/ACROSS THE
DEVELOPING MASS OF CONVECTION SUGGESTS UPSCALE PROGRESSIVE MCS
/POSSIBLE DERECHO/ EVOLUTION THROUGH THE EVENING HOURS. GIVEN
ANTECEDENT AIRMASS CHARACTERISTICS...STRENGTH OF LARGE SCALE
FORCING...AND DEPICTION OF CURRENT CONDITIONS...RELATIVELY HIGH
CONFIDENCE EXISTS IN A NUMBER OF STORM-SCALE MODEL SIMULATIONS
SHOWING MCS/DERECHO EVOLUTION WITHIN THE HIGH RISK AREA THROUGH THE
EVENING HOURS. WRF-ARW SIMULATION FROM 00Z TAKES THE APEX OF THE
PROGRESSIVE MCS FROM CHICAGO TO DETROIT IN UNDER 6 HOURS WITH A
FORWARD SPEED IN EXCESS OF 40KT. SHEAR AND INSTABILITY WITHIN AND
AHEAD OF THIS CONVECTION WILL REMAIN SUPPORTIVE OF BOTH HIGH WINDS
POSSIBLY WELL IN EXCESS OF 60KT...AS WELL A FEW TORNADOES POSSIBLY
ASSOCIATED WITH SUPERCELL STRUCTURES EMBEDDED WITHIN THE SQUALL
LINE/QLCS.

...OH EAST TO EAST COAST/SOUTHEAST...
WARM MOIST AIRMASS ALSO EXISTS WELL EAST OF THE STRONGER FORCING
ACROSS FROM OH EAST ACROSS THE APPALACHIANS TO EAST COAST. SOME
MODEL SIMULATIONS DEPICT THE POSSIBLE EVOLUTION OF SMALL CONVECTIVE
COMPLEXES DEVELOPING FROM INITIALLY MULTICELLULAR STORMS ACROSS THE
HIGHER TERRAIN THIS AFTERNOON. LARGE SCALE FORCING AND SHEAR REMAIN
SUBTLE/WEAK ACROSS THESE AREAS UNTIL LATE IN THE PERIOD.
HOWEVER...DEGREE OF ANTICIPATED INSTABILITY COULD RESULT IN A FEW
HAIL/WIND EVENTS THROUGH THE EVENING AND POSSIBLY INTO LATE
TONIGHT/EARLY FRIDAY ACROSS THESE PARTS OF THE SLGT RISK AREA.

...MT/NERN WY...
STRONG IMPULSES ROTATING THROUGH THE BASE OF LARGER TROUGH ACROSS
THE PACIFIC NORTHWEST WILL AID ASCENT ACROSS THE NRN ROCKIES THROUGH
THE AFTERNOON. STEEPENING LOW THROUGH MID-LEVEL LAPSE RATES AND
STRENGTHENING SHEAR SHOULD CONTRIBUTE TO A NUMBER OF SUPERCELL
STORMS POSING BOTH HAIL AND WIND THREATS. AN ISOLATED TORNADO MAY
ALSO EVOLVE FROM INITIAL DISCRETE CELLS GIVEN RELATIVELY HIGH
BOUNDARY LAYER MOISTURE AND SUFFICIENT DIRECTIONAL SHEAR IN THE
STORM UPDRAFT LAYER.

..CARBIN/SMITH/BUNTING.. 06/12/2013

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
CURRENT UTC TIME: 1632Z (12:32PM), RELOAD THIS PAGE TO UPDATE THE TIME

[brunota2003]

I can't believe that this thread was just created, and such little talk about it! I've been hearing derecho for a few days, ontop of a high tornado threat...with some major cities in the sights of both! Today has the potential to be one of the worst days we've seen in a long time.

[WeatherGuesser]

There has been a lot of media coverage in the last 24 hours or so.

First HIGH Risk since April of last year.

[Ntxw]

Is this high risk mostly for hail and wind? What do you guys think are the TOR probabilities (aside from the 15% area SPC)? Certainly came out of nowhere.

Edit: It seems from the SPC discussion above it appears derecho is the greatest threat

[CrazyC83]

Is this high risk mostly for hail and wind? What do you guys think are the TOR probabilities (aside from the 15% area SPC)? Certainly came out of nowhere.

Tough to call. I believe personally this may stay tornadic longer, and not really become the derecho progged. Tomorrow looks to be wild too in the heavily populated mid-Atlantic as well...maybe not High Risk, but significant, especially for tornadoes.

[Ntxw]

Is this high risk mostly for hail and wind? What do you guys think are the TOR probabilities (aside from the 15% area SPC)? Certainly came out of nowhere.

Tough to call. I believe personally this may stay tornadic longer, and not really become the derecho progged. Tomorrow looks to be wild too in the heavily populated mid-Atlantic as well...maybe not High Risk, but significant, especially for tornadoes.

HRRR short range certainly backs up your thinking. Shows lots of broken storms in a cluster in N Illiniois, S Wisconsin. I hope this isn't one of those surprise events that loves to overachieve.

[CrazyC83]

ZCZC SPCPWOSPC ALL
WOUS40 KWNS 121655
IAZ000-ILZ000-INZ000-OHZ000-130200-

PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1155 AM CDT WED JUN 12 2013

...SEVERE THUNDERSTORMS EXPECTED OVER PORTIONS OF THE MIDDLE
MISSISSIPPI VALLEY EAST TO THE UPPER OHIO VALLEY AND LOWER GREAT
LAKES THIS AFTERNOON AND TONIGHT...

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
DEVELOPMENT OF WIDESPREAD DAMAGING WINDS AND A FEW STRONG TORNADOES
OVER PARTS OF THE PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY EAST TO
THE UPPER OHIO VALLEY AND LOWER GREAT LAKES THIS AFTERNOON AND
TONIGHT.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE

EXTREME EASTERN IOWA
NORTHERN ILLINOIS
NORTHERN INDIANA
NORTHWEST OHIO

ELSEWHERE...SEVERE STORMS ARE ALSO POSSIBLE FROM PORTIONS OF THE
MID-ATLANTIC STATES INTO THE SOUTHEAST U.S.

SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP RAPIDLY THIS AFTERNOON
OVER PORTIONS OF IOWA...NORTHWEST ILLINOIS AND SOUTHWEST WISCONSIN
WITH A THREAT FOR TORNADOES...LARGE HAIL AND DAMAGING WINDS. SOME OF
THE TORNADOES MAY BE STRONG. WITH TIME...THUNDERSTORMS ARE EXPECTED
TO DEVELOP INTO A FAST-MOVING SQUALL LINE WITH THE PRIMARY THREATS
BEING WIDESPREAD DAMAGING WINDS AND EMBEDDED TORNADOES. A FEW WIND
GUSTS IN EXCESS OF 75 MPH WILL BE POSSIBLE AS THE LINE OF
THUNDERSTORMS MOVES RAPIDLY EAST ACROSS THE SOUTHERN GREAT LAKES AND
OHIO VALLEY REGION THIS EVENING.

ADDITIONAL SEVERE THUNDERSTORMS MAY DEVELOP EASTWARD ALONG A FRONTAL
BOUNDARY INTO THE MID-ATLANTIC REGION WITH A THREAT FOR DAMAGING
WINDS AND LARGE HAIL.

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.

..CARBIN/SMITH/BUNTING.. 06/12/2013

$$

[JonathanBelles]

Huge sports risk today! from twitter: @alexanderhall #Blackhawks #Bruins #WhiteSox #BlueJays fans - please follow @NWSChicago and put them on SMS update.

[CrazyC83]

12Z guidance seems to be trending north too...greatest threat may be moving up towards the I-90 corridor up to southern Michigan as well, and perhaps towards NYC tomorrow instead of DC...

[apocalypt-flyer]

Ok, that answers my question in the stickied thread. 11million in the HIGH area, really SMACK ON over the Chicago metro.

Could be a busy busy day/evening.

[brunota2003]

Down here in eastern KY, my weather station is reading 93F with a dew point of 80F. Yikes!

[CrazyC83]

Little change for tomorrow, slight expansion west:

SPC AC 121730

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT WED JUN 12 2013

VALID 131200Z - 141200Z

...THERE IS A MDT RISK OF SVR TSTMS FROM ERN VA...MD...DEL...SRN
NJ...SERN PA...

...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE MID
ATLANTIC...

...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE NRN HIGH
PLAINS...

...SYNOPSIS...

A SHORTWAVE TROUGH OVER THE NRN PLAINS IS CRESTING CNTRL U.S. UPPER
RIDGE...AND WILL RESULT IN AMPLIFICATION OF DOWNSTREAM MEAN TROUGH
ACROSS THE MID ATLANTIC AND NERN U.S. THURSDAY. MEANWHILE...THE
UPPER TROUGH OVER THE PACIFIC NW WILL MOVE SLOWLY EWD INTO THE NRN
INTERMOUNTAIN REGION.

SFC CYCLONE WILL SHIFT EWD THROUGH THE MID ATLANTIC IN ASSOCIATION
WITH DEEPER FORCING ATTENDING THE ERN U.S. SHORTWAVE TROUGH. BY 12Z
THURSDAY A COLD FRONT SHOULD EXTEND FROM THE SFC LOW OVER PA...SWWD
INTO THE OH AND LOWER MS VALLEY REGION. THIS BOUNDARY WILL ADVANCE
SEWD DURING THE DAY...REACHING THE ATLANTIC SEABOARD LATER THURSDAY
EVENING WITH TRAILING PORTION EXTENDING INTO THE SERN STATES. WARM
FRONT EXTENDING EWD FROM THE LOW WILL LIFT SLOWLY NWD THROUGH THE
MID ATLANTIC STATES...LIKELY AS FAR NORTH AS NJ.

...MID ATLANTIC REGION...

SWLY WINDS AHEAD OF THE DEVELOPING CYCLONE WILL TRANSPORT UPPER 60S
DEWPOINTS THROUGH PRE-FRONTAL WARM SECTOR BENEATH RESIDUAL PLUME OF
7 C/KM MID LEVEL LAPSE RATES. THE ATMOSPHERE IS EXPECTED TO BECOME
MODERATELY UNSTABLE AS DIABATIC WARMING COMMENCES WITH MLCAPE FROM
2000-3000 J/KG POSSIBLE. MEANWHILE...STRONGER WINDS IN THE 700-500
MB LAYER ROUNDING BASE OF AMPLIFYING SHORTWAVE TROUGH WILL SPREAD
OVER THE WARM SECTOR DURING THE AFTERNOON. STRENGTHENING DEEP LAYER
WLY WINDS SHOULD RESULT IN A DOWNSLOPING REGIME IMMEDIATELY EAST OF
SRN/CNTRL APPALACHIANS...SUGGESTING IT MIGHT BE DIFFICULT FOR ANY
ONGOING STORMS SURVIVE CROSSING THE MOUNTAINS. HOWEVER...PRE FRONTAL
TROUGH/CONVERGENCE AXIS WILL LIKELY EVOLVE FARTHER EAST FROM THE
CNTRL CAROLINAS INTO CNTRL/ERN VA. ADDITIONAL STORMS WILL LIKELY
DEVELOP ALONG THIS CONVERGENCE ZONE OR AS COLD FRONT OVERTAKES THE
DESTABILIZING WARM SECTOR. DEEP LAYER WIND PROFILES WILL BE LARGELY
UNIDIRECTIONAL WITH SWLY FLOW IN THE SFC-3 KM LAYER SOUTH OF SFC
LOW. THE 0-6 KM VERTICAL SHEAR OF 30-40 KT WILL SUPPORT POTENTIAL
FOR A FEW SUPERCELLS ESPECIALLY WITHIN 2-3 HOURS OF INITIATION.
HOWEVER...TENDENCY MAY BE FOR SOME OF THIS ACTIVITY TO EVOLVE INTO
LINE SEGMENTS WITH LEWP/BOW STRUCTURES. WIDESPREAD DAMAGING WIND AND
LARGE HAIL ARE EXPECTED TO BE THE MAIN THREATS...THOUGH A FEW
TORNADOES CANNOT BE RULED OUT.

...SERN STATES...

LOW 70S BOUNDARY LAYER DEWPOINTS ARE IN PLACE AND WILL SUPPORT
MODERATE INSTABILITY /2000-2500 J/KG MLCAPE/ AS THE SFC LAYER WARMS
AND DESTABILIZES DURING THE AFTERNOON. A BELT OF STRONGER MID-UPPER
WINDS WILL DROP SEWD OVER THE WARM SECTOR AS THE UPPER TROUGH
AMPLIFIES THE EAST OF THIS REGION. THIS WILL RESULT IN NWLY DEEP
LAYER WINDS AND EFFECTIVE SHEAR OF 30-35 KT THAT WILL BECOME AT
LEAST MARGINALLY SUPPORTIVE OF ORGANIZED STORMS. CURRENT INDICATIONS
ARE THAT A FEW STORMS MAY BE ONGOING OVER THE TN VALLEY REGION...AND
ADDITIONAL ACTIVITY MAY DEVELOP/INTENSIFY ALONG THE SWD MOVING
OUTFLOW BOUNDARIES. DAMAGING WIND AND LARGE HAIL WILL BE THE MAIN
THREATS.

..ERN MT AND THE NRN HIGH PLAINS REGION...

COLD FRONT AND ASSOCIATED UPPER TROUGH WILL ADVANCE EWD INTO A
DESTABILIZING AFTERNOON AIRMASS. EXPECT ISOLATED THUNDERSTORMS TO
DEVELOP -- INITIALLY OVER CENTRAL AND ERN MT AND ADJACENT NERN WY.
WHILE STRONG CAPPING -- OWING TO THE PRECEDING INFLUENCE OF UPPER
RIDGE -- SUGGESTS THAT COVERAGE WILL BE LIMITED...STORMS WHICH DO
DEVELOP WILL LIKELY BECOME SEVERE/SUPERCELLULAR GIVEN MODERATE
INSTABILITY AND AMPLE VEERING/SHEAR. HAIL AND DAMAGING WINDS WILL
BE THE PRIMARY SEVERE THREATS THROUGH THE AFTERNOON. STORMS SHOULD
SPREAD EWD ACROSS ERN MT TOWARD WRN SD INTO THE EVENING...AS A SELY
LOW-LEVEL JET INCREASES ACROSS THE HIGH PLAINS. SHEAR WILL CONTINUE
TO FAVOR SEVERE POTENTIAL...WITH CONTINUED THREAT FOR DAMAGING WINDS
AND HAIL AND POSSIBLY AN ISOLATED TORNADO.

..DIAL.. 06/12/2013

CLICK TO GET WUUS02 PTSDY2 PRODUCT

NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z
CURRENT UTC TIME: 1733Z (1:33PM), RELOAD THIS PAGE TO UPDATE THE TIME

[EF-5bigj]

What is the tornado risk for this?

[CrazyC83]

Tornado watch coming. Could be PDS.

MESOSCALE DISCUSSION 1041
NWS STORM PREDICTION CENTER NORMAN OK
1249 PM CDT WED JUN 12 2013

AREAS AFFECTED...PORTIONS OF CENTRAL/ERN IA...SWRN WI...NWRN IL

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 121749Z - 121845Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...A TORNADO WATCH WILL BE COORDINATED WITH LOCAL NWS WEATHER
FORECAST OFFICES PRIOR TO 19Z. SVR TSTMS ARE EXPECTED TO DEVELOP
OVER PORTIONS OF NORTHERN/EASTERN IA AND NORTHWEST ILLINOIS THIS
AFTERNOON AND QUICKLY BECOME SEVERE WITH A RISK FOR
TORNADOES...LARGE HAIL AND DAMAGING WINDS.

DISCUSSION...SURFACE MESOANALYSIS AT 17Z INDICATES AN AREA OF LOW
PRESSURE OVER CENTRAL IOWA AND A FRONTAL BOUNDARY EXTENDING EASTWARD
ALONG THE ILLINOIS/WISCONSIN BORDER. LATEST VISIBLE SATELLITE
IMAGERY SHOWS A DEVELOPING CU FIELD AS DIABATIC HEATING REDUCES
MLCINH. TOWERING CU EVIDENT WEST/NW OF DES MOINES SUGGESTS THAT
CONVECTIVE INITIATION MAY OCCUR WITHIN THE NEXT FEW HOURS. THE
ENVIRONMENT IS CHARACTERIZED BY MODERATE/STRONG INSTABILITY WITH
MLCAPES RANGING FROM 2000 J/KG OVER CENTRAL IOWA TO NEAR 4000 J/KG
OVER EASTERN IOWA/NORTHWEST ILLINOIS. STRONG DEEP-LAYER SHEAR IS
PREVALENT WITH 50-60 KNOTS OVER THE DISCUSSION AREA. LOW-LEVEL /0-3
KM/ SRH FROM THE DAVENPORT VWP OF NEAR 300 M2/S2 SUGGESTS THAT
LOW-LEVEL ROTATION IS POSSIBLE WITH ANY DISCRETE STORM THAT DOES
DEVELOP.

AS AN UPPER LEVEL IMPULSE APPROACHES FROM THE WEST THIS AFTERNOON
AND PROVIDES ADDITIONAL FORCING FOR ASCENT...SEVERE THUNDERSTORMS
ARE EXPECTED TO DEVELOP RAPIDLY NEAR THE SURFACE FRONT AND
INTENSIFYING SURFACE LOW PRESSURE. LOW-LEVEL FLOW WILL BACK WITH
TIME LATER THIS AFTERNOON NORTHEAST OF THE SURFACE LOW...FURTHER
AUGMENTING LOW-LEVEL SRH.

TORNADOES...LARGE HAIL AND DAMAGING WINDS WILL BE POSSIBLE WITH
SUPERCELLS DEVELOPING IN THE DISCUSSION AREA...WITH THE POSSIBILITY
FOR A STRONG TORNADO DURING THE FIRST FEW HOURS AFTER INITIATION.
WITH TIME...UPSCALE GROWTH IS ANTICIPATED AS THE STORMS MOVE EAST
WITH ENHANCED DAMAGING WIND/EMBEDDED MESOVORTEX TORNADO THREATS.

A TORNADO WATCH WILL BE COORDINATED WITH LOCAL NWS WEATHER FORECAST
OFFICES PRIOR TO 19Z.

..BUNTING/CARBIN.. 06/12/2013


ATTN...WFO...MKX...DVN...ARX...MPX...DMX...

LAT...LON 42718972 42368975 41968980 41648993 41559022 41439071
41519144 41559217 41669317 41819403 42539398 42939364
43549311 43729241 43629112 43189045 42718972

[RL3AO]

White Sox game postponed. Good call by MLB/Chicago.

[TYNI]

Huge sports risk today! from twitter: @alexanderhall #Blackhawks #Bruins #WhiteSox #BlueJays fans - please follow @NWSChicago and put them on SMS update.

Was sitting in the back yard waiting for the Jays/White Sox pre-game on the radio. Game has been postponed to a later date.

Stay safe people...

[apocalypt-flyer]

What is the tornado risk for this?

Not a bad time to post this:



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