DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 140553
SWODY2
SPC AC 140551

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1251 AM CDT MON MAY 14 2012

VALID 151200Z - 161200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR SRN WI...FAR NRN IL TUE
AFTERNOON/EVENING...

...SYNOPSIS...
BROAD/WEAK UPPER-LEVEL TROUGH WILL CONTINUE TO ENCOMPASS THE ERN
HALF OF THE CONUS. EMBEDDED WITHIN THIS TROUGH...A SHORT WAVE
IMPULSE SHOULD AMPLIFY SEWD ACROSS ONTARIO INTO THE UPPER GREAT
LAKES...IN THE EXIT REGION OF AN UPPER-LEVEL JET STREAK SHIFTING
SEWD ACROSS THE PRAIRIE PROVINCES. AN ATTENDANT SURFACE COLD FRONT
WILL PUSH SEWD ACROSS THE GREAT LAKES AND UPPER MS VALLEY. FARTHER
SW...A SHORT WAVE IMPULSE WILL DAMPEN AS IT TRACKS ACROSS THE LOWER
RIO GRANDE OF TX TO THE WRN GULF COAST.

...GREAT LAKES...
DIFFERENCES PERSIST WITH THE 00Z NAM DEPICTING A LESS
AMPLIFIED/SLOWER EVOLUTION OF THE APPROACHING SHORT WAVE IMPULSE
COMPARED TO THE 00Z GFS/12Z ECMWF/21Z SREF MEAN. CONSENSUS OF THE
LATTER DEPICT FASTER TIMING OF THE COLD FRONT MOVING SEWD DURING THE
DAY ON TUE. MOISTURE RETURN AHEAD OF THE FRONT SHOULD REMAIN
LIMITED...WITH SURFACE DEW POINTS LIKELY STRUGGLING TO INCREASE
BEYOND THE LOWER 50S. STILL...SUBSTANTIAL HEATING AHEAD OF THE FRONT
SHOULD RESULT IN STEEP LOW/MID-LEVEL LAPSE RATES SUFFICIENT FOR AT
LEAST ISOLATED TSTM DEVELOPMENT ALONG THE FRONT. THE RISK FOR SEVERE
HAIL SHOULD PEAK AROUND 00Z AS MID/UPPER-LEVEL NWLYS STRENGTHEN AND
YIELD SUFFICIENT DEEP-LAYER SHEAR FOR UPDRAFT ROTATION /MOST
PROBABLE IN SRN WI/. THE SUSTENANCE OF THE SEVERE THREAT INTO THE
EVENING IS QUESTIONABLE GIVEN THE PRESENCE OF A RELATIVELY DRY
BOUNDARY LAYER...BUT COULD FAVOR LOCALLY DAMAGING WINDS IF A CLUSTER
OR TWO PERSISTS.

...MID-ATLANTIC/SOUTHEAST...
A BROAD BELT OF 20-30 KT MID-LEVEL SWLYS SHOULD PERSIST DOWNSTREAM
OF A WEAK UPPER-LEVEL TROUGH EXTENDING FROM THE GREAT LAKES TO THE
WRN GULF COAST. ALTHOUGH MID-LEVEL LAPSE RATES SHOULD REMAIN
WEAK...PRESENCE OF LOWER TO MIDDLE 60S SURFACE DEW POINTS AND
POCKETS OF STRONGER DIURNAL HEATING COULD YIELD A FEW MULTICELL
CLUSTERS CAPABLE OF LOCALLY DAMAGING WINDS/MARGINAL HAIL.

...LOWER RIO GRANDE VALLEY OF DEEP S TX...
TIMING OF THE DAMPENING SHORT WAVE IMPULSE IS VARIED WITH THE 00Z
NAM/GFS AND WRF CONVECTION-ALLOWING RUNS FASTER THAN THE 12Z
ECMWF/21Z SREF MEAN. THE LATTER SUGGESTS THAT DIURNAL HEATING WOULD
BE MORE PRONOUNCED AND IN CONJUNCTION WITH A NARROWING CORRIDOR OF
30-40 KT MID-LEVEL WLYS...MAY BE SUFFICIENT FOR A FEW SEVERE STORMS
PRIOR TO CONVECTION MOVING OFF THE COAST.

..GRAMS.. 05/14/2012

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