SPC AC 160547
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1147 PM CST WED FEB 15 2006
   
   VALID 161200Z - 171200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS DURING THURSDAY AFTERNOON AND
   EVENING ACROSS PARTS OF  THE MID MS/LOWER OH VALLEYS...
   
   ...SYNOPSIS...
   A POSITIVE TILT LARGE-SCALE TROUGH WILL PERSIST OVER THE ERN
   PACIFIC...NORTHWEST AND INTERMOUNTAIN U.S...DOWNSTREAM FROM A LARGE
   BLOCKING RIDGE AXIS EXTENDING FROM THE GULF OF ALASKA TO THE
   CANADIAN ARCTIC. BAND OF VERY FAST WLY FLOW ALOFT WILL STRETCH FROM
   THE WEST COAST TO THE GREAT LAKES/APPALACHIANS...BETWEEN THE
   POSITIVE TILT WRN TROUGH AND A BUILDING SUBTROPICAL RIDGE ACROSS THE
   SRN GULF OF MEXICO/BAY OF CAMPECHE. A SHORT WAVE TROUGH EMBEDDED
   WITHIN THIS FAST FLOW REGIME...AND CURRENTLY MOVING ACROSS THE FOUR
   CORNERS REGION...WILL ACCELERATE ENEWD FROM THE HIGH PLAINS TO THE
   ERN GREAT LAKES THROUGH EARLY FRIDAY WITH A BAND OF 100-110KT MID
   LEVEL FLOW SPREADING FROM THE TX/OK PANHANDLES TO WRN PA DURING THE
   FORECAST PERIOD.
   
   STRONG FORCING ASSOCIATED WITH THIS SHORT WAVE IMPULSE AND
   ASSOCIATED WIND MAX WILL INDUCE SURFACE CYCLOGENESIS ALONG A FRONTAL
   ZONE SITUATED ACROSS SRN HIGH PLAINS. RAPID TRANSLATION OF THE LOW
   AMPLITUDE UPPER TROUGH WILL CAUSE THE SURFACE LOW TO QUICKLY REFORM
   EWD ACROSS THE MID MS VALLEY...AND THEN TRACK TO THE LOWER GREAT
   LAKES REGION THROUGH LATE TODAY WHILE DEEPENING. WITH THE PASSAGE OF
   THE INTENSIFYING LOW PRESSURE AREA...A STRONG SURGE OF ARCTIC AIR
   WILL SPREAD SEWD FROM THE CNTRL PLAINS TO THE LOWER MS VALLEY.
   
   ...AR/SERN MO TO OH VALLEY...
   EXPANDING LOW LEVEL MOIST AXIS WAS DEPICTED IN SURFACE OBS AND IR
   SATELLITE IMAGERY FROM ERN TX/OK TO SRN MO LATE TONIGHT AND IS
   EXPECTED TO CONTINUE TO BE TRANSPORTED NWD THROUGH THE MID MS VALLEY
   BY 12Z...AND THEN EWD ACROSS THE LOWER OH VALLEY DURING THE
   AFTERNOON. WHILE A FEW ELEVATED TSTMS WILL BE POSSIBLE WITHIN WARM
   AIR ADVECTION REGIME NORTH OF THE SURFACE FRONT ACROSS THE MIDWEST
   THROUGH THE MORNING...DEVELOPING WARM SECTOR AIR MASS WILL LIKELY
   REMAIN CAPPED TO SURFACE-BASED STORMS DUE TO EML INVERSION EVIDENT
   IN FORECAST SOUNDINGS ACROSS THE REGION.
   
   LATEST SHORT-TERM GUIDANCE IS IN VERY GOOD AGREEMENT THAT THE
   COMBINATION OF SURFACE HEATING AND LARGE SCALE ASCENT AHEAD OF
   APPROACHING UPPER TROUGH AND COLD FRONT WILL BE NEARLY SUFFICIENT TO
   ELIMINATE CONVECTIVE INHIBITION ACROSS CNTRL/SRN MO...WRN IL...AND
   NRN AR BY LATE AFTERNOON. HOWEVER...GUIDANCE ALSO APPEARS TO SUGGEST
   THAT STORM INITIATION OCCURS ON OR IMMEDIATELY BEHIND THE SURFACE
   COLD FRONT AS IT DEVELOPS EWD/SEWD INTO THESE AREAS BY 21Z. INITIAL
   ACTIVITY OVER MO MAY BE UNDERCUT BY THE ADVANCING FRONT AND POSE
   ONLY A LIMITED WIND/HAIL THREAT. A BETTER CHANCE FOR SUSTAINED STORM
   UPDRAFTS TAPPING WEAKLY TO MARGINALLY UNSTABLE BOUNDARY LAYER AIR
   MASS MAY EXIST INVOF SURFACE LOW AND FRONT ACROSS IL/IND INTO EARLY
   EVENING. ALTHOUGH PRIMARILY UNIDIRECTIONAL IN NATURE...VERY STRONG
   LOW LEVEL SHEAR AND FAST STORM MOTION SUGGESTS SUPERCELLS OR BOWING
   LINE SEGMENTS WITH DAMAGING WINDS AND POSSIBLY A BRIEF TORNADO OR
   TWO. DEEPENING COLD POOL...STRONG MID LEVEL DRY INTRUSION...AND MID
   LEVEL FLOW INCREASING TO 90-100KT...ALL SUPPORT THE POSSIBILITY OF
   UPSCALE EVOLUTION INTO A SEVERE SQUALL LINE WITH DAMAGING WINDS
   SPREADING  EAST ACROSS THE MIDWEST/LOWER OH VALLEY THROUGH LATE
   EVENING.
   
   FARTHER SOUTH...FROM AR TO NRN MS...LARGE SCALE DYNAMICS ASSOCIATED
   WITH THE TROUGH AND MID LEVEL JET WILL BE WEAKER THAN ACROSS THE
   MIDWEST. HOWEVER...THESE DEFICIENCIES MAY BE OFFSET BY GREATER
   BOUNDARY LAYER MOISTURE/CAPE AND FORCED ASCENT ALONG THE ADVANCING
   FRONT. A LINEAR MCS WITH WIND AND HAIL POTENTIAL SHOULD DEVELOP
   ACROSS THESE AREAS THROUGH AT LEAST LATE EVENING BEFORE LOOSING
   INTENSITY AS INSTABILITY AND FORCING GRADUALLY WANE WITH EWD/SEWD
   EXTENT.
   
   ..CARBIN.. 02/16/2006
   
   ...NOTICE...
   THE STATION RELATIVE POINTS IN THIS PRODUCT WERE
   DISCONTINUED ON 14 FEBRUARY 2006 AND ARE NOW AVAILABLE
   IN THE FOLLOWING PRODUCTS:
   
      WMO HEADER:       AWIPS ID:
      WUUS01            PTSDY1
      WUUS02            PTSDY2
      WUUS03            PTSDY3
   
   A SERVICE CHANGE NOTICE ...SCN05-39... PROVIDES DETAILS
   ON THIS TRANSITION. FOR ADDITIONAL DETAILS SEE THE FOLLOWING
   WEB ADDRESS USING LOWER CASE LETTERS:
   WWW.NWS.NOAA.GOV/OM/NOTIF.HTM
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z