Oct 16, 2007 1730 UTC Day 2 Convective Outlook
Updated: Tue Oct 16 17:31:39 UTC 2007
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20071016 1730 UTC Day 2 Outlook Graphic
Probabilistic Graphic
20071016 1730 UTC Day Probabilitic Graphic
   SPC AC 161728
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1228 PM CDT TUE OCT 16 2007
   
   VALID 171200Z - 181200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS WED AFTN/EVE ACROSS MUCH OF
   CNTRL/ERN KS AND OK INTO PARTS OF WRN MO/AR....
   
   ...THERE IS A SLGT RISK OF SVR TSTMS WED/WED NIGHT SURROUNDING THE
   MDT RISK AREA...ACROSS THE CNTRL/SRN PLAINS INTO THE MID MS VLY....
   
   ...SYNOPSIS...
   THE NOSE OF A VERY STRONG WEST NORTHWESTERLY UPPER JET STREAK OVER
   THE EASTERN PACIFIC IS NOW OVERSPREADING CALIFORNIA...AND PROGGED TO
   CONTINUE THROUGH THE SOUTHERN ROCKIES BY 12Z WEDNESDAY...AND THE
   MIDDLE/LOWER MISSISSIPPI VALLEY BY 12Z THURSDAY.  MUCH OF MODEL
   GUIDANCE INDICATES THAT...AS THIS OCCURS...STRONG SURFACE
   CYCLOGENESIS WILL TAKE PLACE TO THE LEE OF THE CENTRAL ROCKIES...
   WITH THE MAIN SURFACE LOW LIKELY TO LIFT OUT OF THE CENTRAL PLAINS
   THROUGH THE MIDDLE MISSOURI VALLEY BY LATE WEDNESDAY NIGHT/EARLY
   THURSDAY.  THIS WILL SUPPORT A NORTHWARD RETURN FLOW OF MOISTURE
   FROM THE SOUTHERN PLAINS/RIO GRANDE VALLEY.
   
   RICHER BOUNDARY LAYER MOISTURE OVER THE WESTERN GULF OF
   MEXICO...CHARACTERIZED BY LOWER/MID 70S DEW POINTS...WILL PROBABLY
   NOT BECOME ENTRAINED INTO THE DEVELOPING SYSTEM OVER THE PLAINS. 
   BUT...THIS MOISTURE IS EXPECTED TO ADVECT TOWARD THE LOWER
   MISSISSIPPI VALLEY/CENTRAL AND EASTERN GULF COAST REGION...AS A
   TROPICAL PERTURBATION NOW OVER THE WESTERN GULF OF MEXICO
   ACCELERATES NORTH NORTHEASTWARD...AHEAD OF THE DEVELOPING SOUTH
   CENTRAL PLAINS POLAR TROUGH.
   
   THE FIRST IN A SERIES OF IMPULSES EMBEDDED WITHIN THE POLAR JET IS
   PROGGED EAST OF THE SOUTHERN ROCKIES INTO THE SOUTHERN PLAINS LATE
   TONIGHT INTO EARLY WEDNESDAY.  AND...AMPLIFICATION OF A LARGER SCALE
   TROUGH WILL CONTINUE THROUGH THE REMAINDER OF THE PERIOD AS A MORE
   SIGNIFICANT IMPULSE/JETLET DIGS TO THE LEE OF THE CENTRAL/ SOUTHERN
   ROCKIES.
   
   ...CENTRAL/SOUTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY...
   
   POTENTIAL FOR AN OUTBREAK OF SEVERE STORMS DOES EXIST FOR
   WEDNESDAY...INCLUDING THE POSSIBILITY OF ISOLATED STRONG TORNADOES.
   
   MOISTURE RETURN AND LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION
   WITH INITIAL IMPULSE ARE EXPECTED TO SUPPORT A RAPID INCREASE IN
   CONVECTIVE DEVELOPMENT EARLY IN THE PERIOD...PARTICULARLY FROM PARTS
   OF THE SOUTH CENTRAL PLAINS THROUGH THE OZARK PLATEAU REGION.  MUCH
   OF THIS ACTIVITY LIKELY WILL BE ELEVATED ABOVE A LINGERING
   COOL/STABLE LOW-LEVEL ENVIRONMENT ASSOCIATED WITH A WEAKENING LOW/
   MID-LEVEL CYCLONE NOW LIFTING NORTHEAST OF THE MID MISSOURI VALLEY. 
   SOME OF THESE STORMS...MAINLY WHERE STRONGER MID-LEVEL COOLING
   CONTRIBUTES TO STEEPER MID-LEVEL LAPSE RATES ACROSS THE SOUTH
   CENTRAL PLAINS...COULD CONTAIN SOME LARGE HAIL.  HOWEVER...THIS
   THREAT MAY DIMINISH AS CONVECTION/CLOUDS AND PRECIPITATION BECOME
   INCREASINGLY WIDESPREAD AND DEVELOP NORTHEASTWARD/EASTWARD THROUGH
   THE DAY.
   
   THE PROSPECT FOR CONSIDERABLE EARLY CONVECTION...IN CONJUNCTION WITH
   LOWER SUN ANGLE/SEASONABLY WEAKER DAYTIME HEATING...PROVIDE
   UNCERTAINTY REGARDING THE MAGNITUDE AND EXTENT OF SEVERE THREAT
   LATER WEDNESDAY...AND PARTICULARLY WEDNESDAY EVENING/NIGHT. 
   HOWEVER...IT APPEARS LIKELY THAT A LEAST A NARROW CORRIDOR OF
   SURFACE HEATING WILL OCCUR ALONG/JUST EAST OF A DRY LINE EXPECTED TO
   CURVE SOUTHEAST/SOUTH OF A DEEPENING SURFACE LOW OVER WESTERN KANSAS
   BY 21Z WEDNESDAY.  IN THE PRESENCE OF STEEP LAPSE RATES BENEATH A
   MID-LEVEL THERMAL TROUGH...MODELS ARE SUGGESTIVE THAT MIXED LAYER
   CAPE WILL EXCEED 1000 J/KG...AND THERMODYNAMIC PROFILES WILL BE
   CONDUCIVE TO STRONG UPDRAFTS.  COUPLED WITH STRONG DEEP LAYER NEAR A
   90+ KT WESTERLY 500 MB JET STREAK...THE ENVIRONMENT WILL BE
   FAVORABLE FOR SUPERCELLS WITH VERY LARGE HAIL/ LOCALIZED DAMAGING
   WINDS.  AND...LARGE LOW-LEVEL HODOGRAPHS BENEATH A 40-50+ KT
   SOUTHERLY 850 MB JET WILL SUPPORT THE RISK FOR A FEW
   TORNADOES...SOME OF WHICH COULD BECOME STRONG ACROSS PARTS OF
   CENTRAL/EASTERN KANSAS AND OKLAHOMA.
   
   SEVERE THREAT WILL CONTINUE AT LEAST INTO EARLY EVENING.  AND... IF
   DESTABILIZATION IS NOT SUBSTANTIALLY IMPEDED BY EARLIER
   CONVECTION...SEVERE POTENTIAL COULD CONTINUE NORTHEASTWARD THROUGH
   THE MIDDLE MISSISSIPPI VALLEY WEDNESDAY NIGHT.  BUT...AGAIN...THIS
   IS HIGHLY UNCERTAIN AT THE PRESENT TIME.
   
   ...LOWER MS VALLEY/TN VALLEY AND ERN GULF STATES...
   UNCERTAINTY ALSO EXISTS...BUT A SEVERE THREAT COULD ACCOMPANY A
   LINGERING LOW/MID-LEVEL CIRCULATION LIFTING INLAND OUT OF THE
   WESTERN GULF OF MEXICO.  INSTABILITY WILL LIKELY BE LIMITED DUE TO
   WEAK LAPSE RATES...BUT INLAND ADVECTION OF A MOIST BOUNDARY LAYER
   WITH 70F+ DEW POINTS AND STRENGTHENING LOW-LEVEL WIND FIELDS/SHEAR
   COULD SUPPORT THE RISK FOR ISOLATED TORNADOES/DAMAGING WINDS.
   
   ..KERR.. 10/16/2007
   
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