SPC Outlook Update
Posted by JAC on 5/23/2011, 9:25 am


DAY 1 CONVECTIVE OUTLOOK  
  NWS STORM PREDICTION CENTER NORMAN OK
  0800 AM CDT MON MAY 23 2011
 
  VALID 231300Z - 241200Z
 
  ...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF THE SRN PLNS AND
  OZARKS...
 
  ...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF THE MIDWEST/OH
  VLY...
 
  ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK
  AREA...FROM N TX NEWD TO THE LWR GRT LKS/MID ATLANTIC...
 
  ...SYNOPSIS...
  WI UPR TROUGH EXPECTED TO CONTINUE E INTO NRN LWR MI LATER TODAY AS
  IT BECOMES INCREASINGLY ABSORBED WITHIN LARGER SCALE TROUGH TO ITS
  N.  BAND OF 50+ KT 700 MB FLOW ON S SIDE OF TROUGH...JUST NOW
  CROSSING THE MS RVR INTO IL...SHOULD SPREAD E ACROSS IND...OH
  AND WRN NY/PA LATER TODAY/TONIGHT.  MEANWHILE...WRN U.S. TROUGH WILL
  CONTINUE TO AMPLIFY SE ACROSS THE DESERT SW.  A WEAK LEAD IMPULSE
  NOW OVER NM PER WV IMAGERY...PROFILER...AND VWP DATA...SHOULD
  CONTINUE ENE ACROSS THE SRN PLNS TODAY AND THE OZARKS
  TONIGHT...WITHIN MODERATE WSW SRN BRANCH FLOW.
 
  FEATURES WILL BE RELATIVELY WEAK AT LWR LVLS...BUT WILL THERE WILL
  EXIST A LARGELY STNRY WSW-ENE ORIENTED FRONT FROM SRN KS INTO
  MO...AND SEVERAL SIMILARLY-ORIENTED CONFLUENCE ZONES/COLD FRONTAL
  SEGMENTS OVER THE MIDWEST/OH VLY IN ASSOCIATION WITH AFOREMENTIONED
  MID LVL SPEED MAX.  FARTHER E...A WEAK N-S WARM FRONT WILL MOVE
  SLOWLY E ACROSS THE MID ATLANTIC STATES.
 
  LINGERING RESERVOIR OF STRONG POTENTIALLY UNSTABLE AIR OVER THE SRN
  PLNS EXPECTED TO ONCE AGAIN FOSTER SVR TSTM DEVELOPMENT OVER PARTS
  OF OK AND ADJACENT STATES...WHILE BROAD AREA OF MODERATE TO STRONG
  FLOW JUXTAPOSED WITH SUFFICIENT INSTABILITY FOR STORMS MAY YIELD
  FAIRLY WIDESPREAD COVERAGE OF STRONG TO SVR CONVECTION FROM THE MS
  VLY TO THE MID ATLANTIC CST.
 
  ...SRN PLNS...
  STRONG SFC HEATING OF MOIST/VERY UNSTABLE CORRIDOR EXTENDING FROM
  WRN OK ENEWD INTO SE KS/SRN MO AND NW AR SHOULD YIELD SBCAPE OF AOA
  4000 J/KG BY MID-LATE AFTN.  HEATING...COUPLED WITH ASCENT ALONG
  AFOREMENTIONED FRONT AND/OR ALONG OUTFLOW BOUNDARY FROM ONGOING
  STORM CLUSTER IN SE KS/NE OK...SHOULD SUPPORT DEVELOPMENT OF SCTD
  INTENSE STORMS BY LATE AFTN.  DEVELOPMENT OVER ERN PORTION OF MDT
  RISK AREA MAY BE FURTHER AUGMENTED BY ASCENT DUE TO NM UPR IMPULSE.
 
  GIVEN CONTINUING PRESENCE OF SRN BRANCH JET...AMPLE DEEP SHEAR WILL
  BE PRESENT FOR SUSTAINED STORMS/SUPERCELLS.  COMBINATION OF DEEP EML
  ATOP RICH BOUNDARY LAYER MOISTURE SHOULD ONCE AGAIN SUPPORT
  INSTANCES OF VERY LARGE HAIL AND LOCALLY DMGG WIND.  WHILE LOW LVL
  SPEED/DIRECTIONAL SHEAR SHOULD REMAIN MODEST...SOME RISK ALSO WILL
  EXIST FOR TORNADOES GIVEN DEGREE OF INSTABILITY...ESPECIALLY INVOF
  STALLED OUTFLOW BOUNDARIES/FRONTAL SEGMENTS.
 
  SOME OF THE STORMS...LIKELY IN THE FORM OF A CLUSTER OR TWO... COULD
  LINGER THROUGH LATE TONIGHT...ESPECIALLY IN SRN MO AND AR WHERE
  ACTIVITY WILL BE SUPPORTED BY VEERING BRANCH OF MODERATE BUT VERY
  MOIST LLJ.
 
  ...MIDWEST/OH VLY...
  BAND OF MODERATE TO STRONG DEEP WSW FLOW ON SRN SIDE OF WI/MI UPR
  TROUGH MAY SUPPORT DEVELOPMENT OF ONE OR MORE BANDS OF
  FORWARD-PROPAGATING TSTMS BY EARLY TO MID AFTN OVER PARTS OF IL/IND
  AND SRN MI...WHERE HEATING AND LARGE SCALE FORCING FOR ASCENT SHOULD
  BE STRONGEST IN WAKE OF OVERNIGHT OH/KY MCS.  CONTINUED LOW LVL AIR
  MASS RECOVERY DOWNSTREAM MAY ALLOW STORMS TO SPREAD E INTO  OH AND
  WRN NY/PA LATER IN THE DAY.  STRENGTH OF WIND FIELD AND DEGREE OF
  INSTABILITY /SBCAPE TO 2500 J PER KG/ SUGGEST GOOD POTENTIAL FOR
  DMGG WIND AND HAIL.
 
  ...MID ATLANTIC...
  OH/KY MCS AND ASSOCIATED MCV SHOULD CONTINUE ENEWD LATER THIS
  MORNING...AND CRESTING PARTS THE APPALACHIANS BY EARLY AFTN.
  DOWNSTREAM DESTABILIZATION SHOULD BE SUFFICIENT TO SUPPORT
  INTENSIFICATION OF REMAINING STORMS...AND/OR DEVELOPMENT OF NEW
  ACTIVITY JUST AHEAD OF SYSTEM OVER PARTS OF WV/VA/NC/MD/PA AND NY.
  STRENGTH OF LWR TROPOSPHERIC FLOW SUGGESTS POTENTIAL FOR LOCALLY
  DMGG WIND WITH THE STORMS DESPITE RELATIVELY WEAK LAPSE RATES...AND
  POSSIBLY A TORNADO OR TWO INVOF SLOWLY-MOVING WARM FRONT.
 
  ...CNTRL GRT BASIN/CNTRL RCKYS...
  AMPLIFYING UPR TROUGH WITHIN LARGER-SCALE CYCLONIC FLOW OVER THE WRN
  U.S. SHOULD AFFECT PARTS OF THE GRT BASIN AND CNTRL RCKYS THIS
  AFTN/EVE.  ASSOCIATED STEEPENING OF MID LVL LAPSE RATES
  ATOP HEATED BOUNDARY LAYER SHOULD SUPPORT MODEST DESTABILIZATION
  ACROSS THE REGION...AND THE DEVELOPMENT OF NUMEROUS STORMS.
 
  WHILE MID LVL FLOW SHOULD REMAIN MODEST /20 TO 30 KT/...WIND FIELD
  MAY PROVE SUFFICIENT FOR A FEW STRONG/SUSTAINED CELLS WITH LOCALLY
  DMGG WIND AND MARGINALLY SVR HAIL THROUGH EARLY EVENING.
 
  ..CORFIDI/SMITH.. 05/23/2011
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Indy, Detroit, Toledo, Cleveland, Dayton, Columbus Under-the-Gun - JAC, 5/23/2011, 8:37 am
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