SPC May 19, 2012 0600 UTC Day 2 Convective Outlook

SPC 0600Z Day 2 Outlook

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1219 AM CDT SAT MAY 19 2012

VALID 201200Z - 211200Z

...NO SVR TSTM AREAS FORECAST...

...FRONTAL CONVECTION FROM THE UPPER GREAT LAKES TO THE SRN HIGH
PLAINS...

LATEST SHORT-RANGE MODEL GUIDANCE CONTINUES EARLIER TRENDS REGARDING
THE EVOLUTION OF UPPER TROUGH AS IT PROGRESSES SLOWLY DOWNSTREAM
INTO THE MID/UPPER MS VALLEY.  THIS FEATURE WILL PROVE PARTLY
RESPONSIBLE FOR EARLY MORNING ELEVATED CONVECTIVE THREAT ALONG A
POST-FRONTAL CORRIDOR FROM SRN MN TOWARD THE WRN TIP OF LAKE
SUPERIOR.  STRONGEST FLOW ALOFT WILL STRUGGLE TO OVERSPREAD THE WARM
SECTOR EXCEPT POSSIBLY ACROSS WRN/NRN PORTIONS OF WI.  BOTH THE NAM
AND GFS SUGGEST FAIRLY STRONG BOUNDARY LAYER HEATING IMMEDIATELY
AHEAD OF THE FRONT ALONG THE MS VALLEY WHICH SHOULD ENHANCE LAPSE
RATES/INSTABILITY BY EARLY AFTERNOON SUCH THAT SBCAPE VALUES COULD
APPROACH 2000 J/KG PRIOR TO TSTM INITIATION ALONG THE WIND SHIFT.
GIVEN THE EXPECTED DESTABILIZATION ACROSS WI INTO THE U.P. OF MI
HAVE EXPANDED LOW SEVERE PROBS TO ACCOUNT FOR THE THREAT OF
HAIL/WIND WITH AFTERNOON CONVECTION.  IF STRONGER FLOW CAN INTERACT
WITH FRONTAL CONVECTION THERE MAY BE AN ENHANCED RISK OF SEVERE DUE
TO MORE ORGANIZED UPDRAFTS.

FARTHER SW ALONG THE TRAILING COLD FRONT...DAYTIME HEATING WILL
CONTRIBUTE TO AIR MASS DESTABILIZATION WITHIN AN OTHERWISE FAIRLY
NONDESCRIPT LARGE SCALE PATTERN.  DEEP LAYER SHEAR IS EXPECTED TO
REMAIN WEAK AS ROUGHLY 20KT OF MID LEVEL FLOW MAY SPREAD ACROSS THE
WIND SHIFT.  EARLY IN THE PERIOD WEAK WARM ADVECTION MAY CONTRIBUTE
TO THE LONGEVITY OF OVERNIGHT CONVECTION AS IT DRIFTS ACROSS ERN
KS/NWRN HALF OF OK.  IT/S NOT ENTIRELY CLEAR CONVECTIVE
DEBRIS/OUTFLOW WILL INHIBIT HEATING ALONG THE BOUNDARY EARLY BUT
WITH MID DAY DISSIPATION RENEWED THUNDERSTORM DEVELOPMENT IS
POSSIBLE.  MARGINALLY SEVERE HAIL AND GUSTY WINDS ARE THE PRIMARY
THREATS WITH STRONGEST STORMS.

...ELSEWHERE...

SCATTERED THUNDERSTORMS WILL ONCE AGAIN DEVELOP ACROSS PARTS OF THE
CNTRL/SRN FL PENINSULA AND OVER PORTIONS OF THE MIDDLE ATLANTIC
BENEATH STATIONARY UPPER TROUGH.  WITH 20-25KT OF MID LEVEL FLOW
EXPECTED ACROSS THE PENINSULA THERE MAY BE A PROPENSITY FOR ROBUST
UPDRAFTS IF SUFFICIENT INSTABILITY CAN DEVELOP.  LOW SEVERE PROBS
MAY NEED TO BE ADDED TO THIS REGION IN LATER OUTLOOKS TO ACCOUNT FOR
ISOLATED SEVERE HAIL/WIND THREAT.

..DARROW.. 05/19/2012

via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day2otlk_0600.html