DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 281732
SWODY2
SPC AC 281730

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CST MON JAN 28 2013

VALID 291200Z - 301200Z

...THERE IS A MDT RISK OF SVR TSTMS FROM NRN LA...CNTRL AND ERN
AR...EXTREME SWRN TN AND NWRN TO WCNTRL MS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE SRN
PLAINS...LOWER THROUGH MID MS VALLEY INTO WRN PARTS OF THE TN AND OH
VALLEYS...

...SYNOPSIS...

THE HIGH AMPLITUDE UPPER TROUGH NOW OVER THE WRN U.S. WILL ADVANCE
EWD...WITH MODEL CONSENSUS INDICATING THAT THE TROUGH AXIS WILL BE
LOCATED FROM MN THROUGH CNTRL/ERN TX BY THE END OF THIS PERIOD. MID
LEVEL JET AND ATTENDANT VORT MAX LOCATED WITHIN BASE OF THE TROUGH
SHOULD EJECT FROM THE SRN PLAINS THROUGH THE LOWER-MID MS VALLEY
TUESDAY NIGHT. AS THIS OCCURS A CYCLONE WILL DEEPEN AND LIFT NEWD
THROUGH THE MID MS VALLEY REGION. A POLAR FRONT WILL EXTEND FROM THE
SFC LOW OVER IA SWWD INTO CNTRL/SRN HIGH PLAINS EARLY TUESDAY...WITH
A PACIFIC FRONT/DRYLINE EXTENDING SWD THROUGH WRN TX. POLAR FRONT
WILL ADVANCE SEWD DURING THE DAY...WHILE THE PACIFIC FRONT SURGES
EWD AND MERGES WITH DRYLINE...CONTINUING THROUGH THE LOWER MS VALLEY
OVERNIGHT.

...SRN PLAINS THROUGH LOWER MS VALLEY REGION...

POTENTIAL EXISTS FOR A SIGNIFICANT SEVERE WEATHER EVENT TUESDAY WITH
DAMAGING WIND AND TORNADOES THE PRIMARY THREATS...ESPECIALLY DURING
THE EVENING AND OVERNIGHT IN MODERATE RISK AREA. OBSERVATIONS SHOW A
RESERVOIR OF MIDDLE TO UPPER 60S DEWPOINTS FROM CNTRL INTO SRN TX.
SLY BOUNDARY LAYER FLOW ALREADY EXISTS FROM THE SRN PLAINS INTO THE
LOWER MS VALLEY AND WILL STRENGTHEN TUESDAY IN ASSOCIATION WITH AN
INTENSIFYING LLJ. WIDESPREAD MULTI-LAYER CLOUDS WILL LIMIT BOUNDARY
LAYER WARMING DURING THE DAY. HOWEVER...MID 60S DEWPOINTS SHOULD
ADVECT AS FAR NORTH AS SERN OK INTO CNTRL AR AND NRN MS BENEATH A
PLUME OF 6.5 C/KM MID LEVEL LAPSE RATES RESULTING IN AT LEAST
500-1000 J/KG MLCAPE.

STORMS ARE EXPECTED TO DEVELOP WITHIN PRE-FRONTAL CONFLUENCE BAND
ACROSS CNTRL/ERN OK INTO NCNTRL/NERN TX EARLY TUESDAY AND SHIFT EWD
AND NEWD DURING THE DAY. OTHER STORMS MAY DEVELOP FARTHER SOUTH
THROUGH ERN TX DURING THE AFTERNOON ALONG MERGING PACIFIC FRONT AND
SHIFT EWD THROUGH THE LOWER MS VALLEY. THE BOUNDARY LAYER WILL
MOISTEN SUFFICIENTLY FOR THIS ACTIVITY TO BECOME SFC BASED. STORMS
WILL BE EMBEDDED WITHIN STRONG DEEP LAYER FLOW WITH A 50+ KT SLY LLJ
AND MID LEVEL WINDS INCREASING TO 80 KT. STORMS ARE EXPECTED TO
EVOLVE INTO A PREDOMINANT QLCS WITH EMBEDDED SUPERCELL AND BOWING
SEGMENTS POSING A RISK FOR DAMAGING WIND AND TORNADOES. TORNADO
THREAT MAY INCREASE OVERNIGHT...ESPECIALLY IN MODERATE RISK AREA
WHERE LLJ INTENSIFYING TO IN EXCESS OF 70 KT WILL BE COLLOCATED WITH
NRN EDGE OF MID 60S DEWPOINTS.

...UPPER MS VALLEY THROUGH TN VALLEY REGION...

OTHER STORMS WILL EXPAND NEWD THROUGH THE MID MS VALLEY AND SWRN
PARTS OF OH VALLEY WHERE INSTABILITY WILL BE MORE LIMITED...BUT
SUFFICIENT FOR A THREAT FOR DAMAGING WIND WITH PRIMARY MODE BEING
LINES AND BOWING SEGMENTS WITH MESO VORTICES. A FEW EMBEDDED
SUPERCELLS WILL ALSO BE POSSIBLE GIVEN SIZE OF HODOGRAPHS AND
STRENGTH OF DEEP LAYER FLOW/SHEAR SUGGESTING A FEW TORNADOES CANNOT
BE RULED OUT.

..DIAL.. 01/28/2013

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