DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 160556
SWODY1
SPC AC 160554

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1154 PM CST FRI NOV 15 2013

VALID 161200Z - 171200Z

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS OF THE MID-MO AND
MID-MS VALLEYS...

...SYNOPSIS...
A LARGE-SCALE TROUGH WILL EXTEND FROM THE PACIFIC COAST TO THE GREAT
LAKES...WITH A LEAD EMBEDDED SHORTWAVE FORECAST TO SHIFT FROM THE
CENTRAL PLAINS INTO THE UPPER GREAT LAKES. FARTHER UPSTREAM...A MORE
POTENT EMBEDDED SHORTWAVE WILL AMPLIFY ACROSS THE CENTRAL ROCKIES
AND CENTRAL PLAINS LATE IN THE PERIOD...AND CONTRIBUTE TO A
STRENGTHENING OF DEEP-LAYER WIND FIELDS ACROSS THE CENTRAL CONUS.

AT THE SFC...INITIAL FRONTAL WAVE ACCOMPANYING THE LEAD SHORTWAVE
TROUGH WILL QUICKLY PROGRESS NEWD ACROSS THE UPPER MS VALLEY AND
UPPER GREAT LAKES. LOW-LEVEL MOISTURE WILL ADVECT NWD THROUGHOUT THE
PERIOD AS A SFC LOW DEEPENS OVER IA EARLY SUN MORNING.

...PORTIONS OF THE MID-MO AND MID-MS VALLEYS...
A SHORTWAVE UPPER TROUGH MOVING THROUGH THE CENTRAL ROCKIES AND
CENTRAL HIGH PLAINS IS FORECAST TO MINOR OUT AND EJECT NEWD.
ASSOCIATED SFC CYCLOGENESIS WITH THIS FEATURE IS EXPECTED TO BE
RATHER WEAK...BUT SFC LOW AND ATTENDANT FRONTAL WAVE ARE FORECAST TO
ACCELERATE NEWD ACROSS THE DAKOTAS AND UPPER MS VALLEY BY 17/03Z.
MEANWHILE...50-60 KT LLJ WILL LIKELY BE MAINTAINED THROUGHOUT THE
DAY FROM THE SRN PLAINS...WITH LOW-LEVEL THETA-E ADVECTION FOCUSED
FROM CENTRAL IA/MO AND POINTS EWD. FORECAST MODELS INDICATE
MID-UPPER 50S F DEWPOINTS WILL SPREAD NWD ACROSS THIS AREA DURING
THE AFTERNOON. DESPITE THE LIKELIHOOD OF COOL SFC TEMPERATURES
/LOW-MID 60S F/...MODERATELY STEEP MIDLEVEL LAPSE RATES /AROUND 7
C/KM/ MAY BE SUFFICIENT TO YIELD MLCAPE VALUES PEAKING AT 500-1000
J/KG. SRN EXTENSION OF THE LEAD SHORTWAVE TROUGH MAY LINGER THROUGH
IA/IL DURING THE LATE AFTERNOON AND EVENING...AND COULD SUPPORT TSTM
DEVELOPMENT ACROSS PARTS OF IA/WRN IL AND NRN MO...ALTHOUGH
UNCERTAINTY REMAINS HIGH GIVEN WEAK FOCUS FOR INITIATION WITHIN THE
WARM CONVEYOR BELT. AS SUCH...ANY SVR POTENTIAL ASSOCIATED WITH LATE
AFTERNOON AND EARLY EVENING ACTIVITY APPEARS TO BE QUITE
CONDITIONAL. HOWEVER...STRONG LOW-/MIDLEVEL SHEAR WILL BE SUFFICIENT
FOR ISOLATED DMGG WIND GUSTS AND PERHAPS A TORNADO.

MORE SUBSTANTIAL FORCING FOR ASCENT...AND ASSOCIATED SVR
POTENTIAL...IS EXPECTED TO ARRIVE LATE SAT EVENING INTO EARLY SUN
MORNING...AS A SHORTWAVE UPPER TROUGH AMPLIFIES OVER THE ROCKIES AND
HIGH PLAINS. PRECEDING MIDLEVEL HEIGHT FALLS AND STRENGTHENING OF
MID/UPPER-LEVEL WIND FIELDS WILL OVERSPREAD THE REGION...AND WITH A
FURTHER STRENGTHENING OF LOW-LEVEL THETA-E ADVECTION...SHOWERS/TSTMS
SHOULD BECOME MORE NUMEROUS THROUGHOUT THE LATE EVENING ACROSS ERN
IA AND IL. A CLUSTER OR LINE MAY EVOLVE OUT OF THIS ACTIVITY AND
SPREAD EWD OVERNIGHT ACROSS IND AND THE LOWER OH VALLEY...BUT SHOULD
ENCOUNTER AN INCREASINGLY STABLE BOUNDARY LAYER AND PRIMARILY BE
ELEVATED. ADDITIONAL TSTM DEVELOPMENT WILL BE POSSIBLE FARTHER W
ALONG A DRYLINE EXTENDING FROM CNTRL IA SWWD TO NEAR MKC...PRIMARILY
AFTER 17/00Z.

BY THE EARLY SUN MORNING...SFC LOW WILL BEGIN TO DEEPEN OVER CNTRL
IA...WITH AN ATTENDANT COLD FRONT ACCELERATING EWD. WITH NEARLY
SATURATED LOW-LEVELS...TSTMS MAY REMAIN NEAR-SFC BASED DURING THE
OVERNIGHT HRS ESPECIALLY WITHIN THE MOIST AXIS/WARM CONVEYOR...AND
COULD SUPPORT A DMGG WIND AND PERHAPS A BRIEF/WEAK TORNADO THREAT
GIVEN STRONG LOW-LEVEL SHEAR. THE POTENTIAL FOR SFC-BASED STORMS
INVOF THE DEEPENING SFC LOW...ESPECIALLY TOWARDS THE END OF THE
PERIOD...IS A BIT MORE UNCERTAIN W OF THE RICHEST MOISTURE.
NONETHELESS...TSTMS WILL BE CAPABLE OF PRODUCING LARGE HAIL AND
POSSIBLY DMGG WIND GUSTS.

..ROGERS/DARROW.. 11/16/2013

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