DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 081259
SWODY1
SPC AC 081258

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0758 AM CDT FRI JUN 08 2012

VALID 081300Z - 091200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE NERN
STATES...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE UPR MS
VLY/UPR GRT LKS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER WRN PARTS OF THE NRN
PLNS...

...SYNOPSIS...
PROGRESSIVE TROUGH/RIDGE/TROUGH PATTERN WILL PREVAIL OVER THE NRN
HALF OF THE CONUS THIS PERIOD...WITH WEAK FLOW ACROSS THE SRN TIER.
CLOSED LOW OFF VANCOUVER ISLAND SHOULD CONTINUE SE INTO ORE BY EARLY
SAT AS A SERIES OF WEAK DOWNSTREAM DISTURBANCES TRACK NE ACROSS ID
AND MT. FARTHER E...SHORTWAVE TROUGH NOW OVER SRN SK/ND LIKELY WILL
WEAKEN AS IT SHEARS ESE IN CONFLUENT FLOW OVER WRN ONT/LK
SUPERIOR...WHILE IMPULSE NOW ENTERING SW QUE AMPLIFIES SE INTO ERN
NEW ENGLAND.

DIURNALLY ENHANCED TSTMS...SOME POSSIBLY SVR...WILL ACCOMPANY THE
SHORTWAVE FEATURES OVER PARTS OF THE NRN PLNS...THE UPR MS VLY...AND
THE NERN STATES.

...NERN U.S. THIS AFTN/EVE...
INCREASING LARGE SCALE ASCENT/UPR DIFFLUENCE WILL OVERSPREAD UPSTATE
NY AND NRN NEW ENGLAND TODAY AHEAD OF UPR IMPULSE AMPLIFYING SEWD
FROM QUE. WHILE THIS WILL LEAD TO AN INCREASE IN HIGH-LVL
CLOUDS...APPROACH OF SYSTEM ALSO WILL BE ACCOMPANIED BY STEEPENING
MID LVL LAPSE RATES. LOW LVL CONVERGENCE WILL REMAIN WEAK...AND
MOISTURE COMPARATIVELY SPARSE. BUT COMBINATION OF INCREASING
ASCENT...STEEPENING MID LVL LAPSE RATES...AND SFC HEATING SHOULD
SUPPORT DEVELOPMENT OF A SHORT BANDS/SMALL CLUSTERS OF STORMS OVER
NRN/ERN NY AND WRN/NRN NEW ENGLAND BY EARLY TO MID AFTN. 30-40 KT
NWLY MID LVL FLOW SHOULD PROVE SUFFICIENT FOR A FEW SUSTAINED
STORMS/MULTICELLS WITH A RISK FOR SVR WIND/HAIL. WHILE BOTH WINDS
AND ASCENT WILL CONTINUE TO INCREASE AFTER SUNSET...THE STORMS
SHOULD DIMINISH WITH ONSET OF DIURNAL COOLING.

...UPR MS VLY/UPR GRT LKS THIS AFTN INTO TNGT...
WEAK WAA/MOISTURE TRANSPORT WILL PREVAIL OVER NE MN...WI...AND UPR
MI TODAY AS SK/ND UPR IMPULSE SHEARS ESE TOWARD ONT. IN WAKE OF
EARLY DAY ELEVATED WAA CONVECTION/STORMS...SFC HEATING...MOISTURE
INFLOW...AND GLANCING INFLUENCE OF UPR TROUGH SHOULD SUPPORT NEW
STORM DEVELOPMENT THIS AFTN GIVEN ABSENCE OF AN APPRECIABLE EML.
30-40 KT SWLY FLOW AT 850 MB VEERING TO NW WINDS OF SIMILAR SPEEDS
AT MID LVLS WILL BE FAVORABLE FOR SUSTAINED STORMS/SUPERCELLS.
CURRENT SFC OBS AND PW DATA SUGGEST...HOWEVER...THAT WARM SECTOR
MOISTURE WILL REMAIN COMPARATIVELY LIMITED FOR THE TIME OF
YEAR...WITH SFC DEWPOINTS LIKELY TO AVERAGE IN THE UPR 50S TO LOW
60S F. AS A RESULT...HAIL AND LOCALLY DMGG WIND SHOULD BE THE MAIN
SVR THREATS. TORNADO OR TWO COULD...HOWEVER...OCCUR...ESPECIALLY IN
NE MN AND NW WI. THE STORMS LIKELY WILL EVOLVE INTO A CLUSTER OVER
NRN MI THIS EVE...WITH A DIMINISHING THREAT FOR SVR.

...MT/WRN ND THIS AFTN INTO TNGT...
STRONG HEATING WILL OCCUR OVER THE NRN HI PLNS TODAY...ESPECIALLY
FROM ERN MT INTO WRN ND/NW SD. MID LVL WINDS WILL INCREASE AND BACK
ACROSS MT TODAY...DOWNSTREAM FROM MAIN UPR LOW/TROUGH MOVING TOWARD
ORE. THIS PATTERN WILL STRENGTHEN LEE SFC LOW OVER THE NRN HI PLNS
AND MAINTAIN LOW LVL ELY FLOW/MOISTURE TRANSPORT OVER CNTRL/ERN MT
AHEAD OF ASSOCIATED COLD FRONT. FOR THIS REASON...AND WITH SFC
HEATING...EXPECT THAT LOW LVL BUOYANCY WILL DEVELOP SUFFICIENTLY FAR
W TO SUPPORT STRONG TSTM DEVELOPMENT JUST E OF THE MT RCKYS BY
MID-LATE AFTN. THESE STORMS SHOULD STRENGTHEN AND MOVE/DEVELOP E
INTO ERN MT THIS EVE...WHERE GREATER INSTABILITY AND LOW LVL SHEAR
WILL EXIST...POSING A RISK FOR SVR HAIL...HIGH WIND...AND POSSIBLY A
COUPLE TORNADOES.

SUSTAINED WAA/MOISTURE TRANSPORT OVER ERN MT SHOULD FAVOR
DEVELOPMENT OF AN MCS OR TWO OVER THE REGION TNGT. THESE SHOULD
MOVE MAINLY E INTO WRN ND LATER TNGT/EARLY SAT...WITH HAIL AND
LOCALLY DMGG WIND THE MAIN SVR THREATS.

..CORFIDI/LEITMAN.. 06/08/2012

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