DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1111 AM CST WED FEB 19 2014
VALID 201200Z - 211200Z
...THERE IS A SLGT RISK OF SVR TSTMS OH/MID AND LOWER MS VALLEYS
INTO THE TN VALLEY AND DEEP SOUTH...
...SYNOPSIS...
AN INTENSE TROUGH WILL SHIFT EWD OUT OF THE PLAINS THURSDAY
AFTERNOON AND ACROSS THE MID MS AND OH VALLEYS/SRN GREAT LAKES
REGION BY 12Z FRIDAY. AT THE SURFACE...ASSOCIATED LOW IN THE
VICINITY OF WRN MO AT THE BEGINNING OF THE PERIOD WILL RAPIDLY
INTENSIFY AND LIFT NEWD TOWARD THE UPPER GREAT LAKES. THUNDERSTORMS
ARE EXPECTED TO INCREASE ALONG AN EWD ADVANCING COLD FRONT DURING
THE EARLY AFTERNOON...WITH A DAMAGING WIND THREAT EXTENDING ROUGHLY
ALONG THE I-70 CORRIDOR FROM SRN IL INTO SRN OH SOUTHWARD ACROSS THE
OH/TN VALLEYS INTO THE DEEP SOUTH INTO THE OVERNIGHT HOURS.
...MID AND LOWER MS VALLEY...OH/TN VALLEY INTO THE DEEP SOUTH...
DESPITE WARMING TEMPERATURES THE LAST FEW DAYS...SUBSTANTIAL SNOW
PACK REMAINS ACROSS PARTS OF NRN IL...SRN LOWER MI AND NRN IND/OH.
WHILE THE INTENSIFYING SFC LOW AND APPROACHING SHORTWAVE IMPULSE
WILL LEAD TO STRONG DEEP LAYER FLOW ACROSS THIS REGION...THE
LINGERING SNOW PACK WILL LIMIT SEVERE POTENTIAL NORTH OF THE I-70
CORRIDOR DUE TO A NEAR SURFACE STABLE LAYER AND WEAK BUOYANCY
LIMITING CONVECTIVELY ENHANCED WIND POTENTIAL.
FURTHER SOUTH...ESPECIALLY TOWARD THE LOWER OH AND TN VALLEY...THE
QUALITY OF THE WARM SECTOR AIRMASS AND LOW LEVEL THERMODYNAMICS
/UPPER 50S F DEWPOINTS...0-3 KM LAPSE RATES NEAR 7.0 DEG C PER KM
AND MUCAPE APPROACHING 1000 J PER KG/ SHOULD BE SUFFICIENT TO
SUPPORT MORE ROBUST THUNDERSTORM UPDRAFTS INTO THE EVENING HOURS.
ADDITIONALLY...THE STRENGTH OF LOW LEVEL WIND FIELDS /50+ KT JUST
OFF THE SFC/ COUPLED WITH A FAST MOVING QLCS COULD LEAD TO
WIDESPREAD DAMAGING WINDS ACROSS PARTS OF FAR SRN IND...PARTS OF
WRN/CNTRL KY INTO PORTIONS OF WRN/MIDDLE TN. STRONG LOW LEVEL SPEED
SHEAR COULD LEAD TO A FEW TORNADOES AS WELL.
THUNDERSTORMS WILL CONTINUE TO DEVELOP SOUTHWARD ALONG/JUST AHEAD OF
THE SFC COLD FRONT INTO THE LOWER MS VALLEY WHERE BETTER MOISTURE
AND A WARMER AIRMASS WILL RESIDE. HOWEVER...THIS AIRMASS WILL NOT BE
JUXTAPOSED WITH BETTER KINEMATIC FIELDS AS THE SFC LOW AND SHORTWAVE
TROUGH CONTINUE TO LIFT NEWD. ADDITIONALLY...FORECAST SOUNDINGS
INDICATE A DRY/WARM LAYER AROUND 700 MB WHICH COULD INITIALLY HINDER
UPDRAFT ORGANIZATION/STRENGTH UNTIL AFTER DARK. BUT...STEEP LOW
LEVEL LAPSE RATES AND A FAST MOVING LINE OF STORMS WILL STILL POSE A
DAMAGING WIND THREAT AS THE LINE TRACKS EWD ACROSS THE DEEP SOUTH
OVERNIGHT.
..LEITMAN/DARROW.. 02/19/2014
