Tornado Alley (PROG)

[F6]

May 24, 2011 1300 UTC Day 1 Convective Outlook

Updated: Tue May 24 12:58:08 UTC 2011


Categorical Day 1 1300Z Outlook


Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.


Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% or greater probability of wind gusts 65 knots or greater within 25 miles of a point.


Probability of one inch diameter hail or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of two inch diameter hail or larger within 25 miles of a point.

Forecast Discussion

    SPC AC 241254 
     
    DAY 1 CONVECTIVE OUTLOOK   
    NWS STORM PREDICTION CENTER NORMAN OK 
    0754 AM CDT TUE MAY 24 2011 
     
    VALID 241300Z - 251200Z 
     
    ...THERE IS A HIGH RISK OF SVR TSTMS OVER PARTS OF OKLAHOMA AND 
    KANSAS... 
     
    ...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK AREA 
    FROM N TX N/NEWD INTO PARTS OF AR AND MO... 
     
    ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE ABOVE AREAS 
    FROM S CNTRL TX THROUGH THE MID MS AND OH VLYS INTO NEW 
    ENGLAND...THE MID ATLANTIC STATES AND NC... 
     
    ...SYNOPSIS... 
    ...TORNADO OUTBREAK EXPECTED OVER PARTS OF THE SRN AND CNTRL PLNS 
    AND OZARKS LATER TODAY INTO TONIGHT... 
     
    POTENT UPR TROUGH NOW CROSSING THE FOUR CORNERS WILL FURTHER 
    STRENGTHEN AND EVOLVE INTO CLOSED LOW OVER THE CNTRL HI PLNS BY THIS 
    EVE AS ASSOCIATED BAND OF 75 KT MID LVL FLOW SWEEPS E/NE ACROSS THE 
    SRN PLNS.  THE LOW WILL CONTINUE E INTO CNTRL KS TONIGHT/EARLY WED 
    AS THE SPEED MAX/VORT LOBE ROTATE NE ACROSS THE OZARKS.  AT THE 
    SFC...LOW NOW OVER THE OK/TX PANHANDLES SHOULD UNDERGO SUBSTANTIAL 
    DEEPENING AS IT MOVES SLOWLY NE INTO S CNTRL KS THIS EVE...AND 
    CONTINUES N/NE INTO CNTRL KS OVERNIGHT.  IN RESPONSE...FLOW AT ALL 
    LVLS SHOULD SUBSTANTIALLY STRENGTHEN OVER THE SRN HALF OF THE PLNS 
    AND OZARKS LATER TODAY THROUGH EARLY WED. 
     
    ...SRN/CNTRL PLNS AND OZARKS LATER TODAY THROUGH TNGT... 
    SETUP STILL APPEARS FAVORABLE FOR SCTD STRONG TSTM DEVELOPMENT BY 
    ABOUT 21Z IN AREA OF STRONG SFC HEATING ALONG AND AHEAD OF DRYLINE 
    EXTENDING S FROM PANHANDLE SFC LOW.  COMBINATION OF STRENGTHENING 
    WIND FIELD...DEEP EML...AND RATHER RICH BOUNDARY LAYER MOISTURE 
    ACROSS REGION WILL SUPPORT A FEW INTENSE SUPERCELLS.  ARRIVAL OF 
    STRONG HEIGHT FALLS/UVV WITH AFOREMENTIONED VORT LOBE SHOULD FOSTER 
    MORE WIDESPREAD STORM DEVELOPMENT ALONG AND AHEAD OF DRY LINE A BIT 
    LATER IN THE DAY OR BY EARLY EVE. 
     
    ALTHOUGH SOME POTENTIAL WILL EXIST FOR POSSIBLE STORM 
    INTERFERENCE...ESPECIALLY WITH NWD EXTENT IN HIGH/MDT RISK 
    AREA...SETUP STILL APPEARS FAVORABLE FOR AT LEAST FEW LONG-LIVED 
    DISCRETE/SEMI-DISCRETE STORMS.  GIVEN STRENGTH OF WIND FIELD AND 
    STRONG LWR TROPOSPHERIC VEERING DUE TO WWD POSITION OF SFC LOW AND 
    SLIGHT NEG TILT OF UPR VORT...POTENTIAL ALSO WILL EXIST FOR 
    LONG-LIVED STRONG TORNADOES...ESPECIALLY IN CNTRL/ERN/NRN OK. 
    WEAK W-E BOUNDARY NOW INVOF THE RED RVR SHOULD MOVE/REDEVELOP NEWD 
    LATER TODAY.  THIS FEATURE MAY SERVE AS A SECONDARY FOCUS FOR STORM 
    DEVELOPMENT...AND/OR ENHANCE LOW LVL HELICITY...OVER PARTS OF 
    CNTRL/ER OK LATER TODAY. 
     
    WITH TIME THE KS/OK/N TX STORMS SHOULD EVOLVE INTO BROKEN LINE 
    SEGMENTS AND POSSIBLY A COMPLEX QLCS WITH EMBEDDED SUSTAINED 
    SUPERCELLS.  THIS ACTIVITY SHOULD MOVE/DEVELOP RAPIDLY NE INTO PARTS 
    OF MO AND AR LATER THIS EVE THROUGH EARLY WED...WITH AN EXPANDING 
    THREAT FOR DMGG WIND IN ADDITION TO A CONTINUING RISK FOR 
    HAIL/TORNADOES.  A PORTION OF THIS ACTIVITY...OR PERHAPS NEW 
    STORMS...MAY AFFECT THE LWR OH VLY REGION BY 12Z WED. 
     
    IN THE NEAR TERM...SLIGHTLY ELEVATED MCS WITH A THREAT FOR HAIL AND 
    POSSIBLY LOCALLY DMGG WIND EXPECTED TO CONTINUE E TO ESE ACROSS 
    CNTRL KS.  OUTFLOW BOUNDARY FROM THIS FEATURE MAY SERVE AS 
    A FOCUS FOR STORM DEVELOPMENT IN CNTRL/ERN KS LATER TODAY. 
     
    ...CNTRL APPALACHIANS INTO VA/NC NOW THROUGH THIS AFTN... 
    ONGOING LOOSELY-ORGANIZED MCS NOW OVER ERN KY/TN APPEARS TO BE 
    SUPPORTED IN PART BY UPR IMPULSE THAT CROSSED THE SRN PLNS 
    YESTERDAY.  AS THE IMPULSE CONTINUES EWD AND BOUNDARY LAYER 
    DESTABILIZES AHEAD OF IT...CONDITIONS MAY BECOME FAVORABLE FOR 
    UPSCALE DEVELOPMENT INTO A N-S ORIENTED FORWARD-PROPAGATING MCS.  
    STRENGTH OF UNIDIRECTIONAL WIND FIELD AND STEEP LOW LVL LAPSE RATES 
    PER GSO 12Z SOUNDING SUGGEST GOOD LIKELIHOOD FOR DMGG WIND.  OTHER 
    STRONG/SVR STORMS MAY FORM AHEAD OF THE MCS ALONG LEE TROUGH IN SE 
    VA/ERN NC. 
     
    ...OH VLY TO MID ATLANTIC/NEW ENGLAND THIS AFTN... 
    ONGOING SHOWERS/SCTD TSTMS MAY BE JOINED POCKETS OF ADDITIONAL 
    DEVELOPMENT LATER TODAY AS AIR MASS DESTABILIZES ALONG/AHEAD OF COLD 
    FRONT ASSOCIATED WITH ERN CANADIAN UPR TROUGH. WHILE THE BELT OF 
    STRONGEST FLOW ALOFT WILL REMAIN S OF THE OH RVR... 
    AMPLE FLOW WILL EXIST FOR ORGANIZED STORMS THAT MAY POSE A THREAT 
    FOR LOCALLY DMGG WIND AND SVR HAIL. 
     
    ..CORFIDI/SMITH.. 05/24/2011 
     
    CLICK TO GET WUUS01 PTSDY1 PRODUCT 
  
    NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z

http://www.spc.noaa.gov/products/outlook/day1otlk.html [use this link for later Day 1 Outlooks, available at 11:30a, 3p and 8p CDT]


=====


Public Severe Weather Outlook [current one in the post to which this is a reply; next one should come out by sometime midday]
http://www.spc.noaa.gov/products/outlook/pwo.html

---

Current Convective Watches
http://www.spc.noaa.gov/products/watch/

---

Severe Weather and Flash Flood Warnings
http://kamala.cod.edu/svr/


=====


and to repeat -- this is another day to get in touch with family and friends in the high/moderate risk areas and relay the message "today, make sure to stay informed on the latest watches and warnings, and just get it together and head straight to good shelter if in particular a tornado warning is issued"