DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 081623
SWODY1
SPC AC 081621

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1121 AM CDT FRI JUN 08 2012

VALID 081630Z - 091200Z

...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTERNOON INTO
TONIGHT FOR THE NRN HIGH PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING
ACROSS PARTS OF THE UPPER GREAT LAKES...

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO EVENING
ACROSS PORTIONS OF THE HUDSON VALLEY INTO NEW ENGLAND...

...SYNOPSIS...

UPPER LOW OFF THE BRITISH COLUMBIA AND WA COASTS WILL MOVE INLAND
INTO THE INTERIOR PACIFIC NW WITH AN ASSOCIATED MIDLEVEL JET STREAK
AND 500-MB HEIGHT FALLS OF 60-90 M/12-HR DEVELOPING EWD ACROSS THE
NRN HIGH PLAINS. DOWNSTREAM FROM THIS FEATURE...A SHORTWAVE TROUGH
CURRENTLY CRESTING MIDLEVEL RIDGE AXIS OVER THE RED RIVER VALLEY
INTO SRN MANITOBA/WRN ONTARIO WILL WEAKEN WHILE PROGRESSING INTO AN
INCREASINGLY CONFLUENT FLOW REGIME OVER THE UPPER GREAT LAKES.
FARTHER E...MID TO UPPER-LEVEL JET STREAKS OVER ERN ONTARIO WILL
DEVELOP SEWD THROUGH THE HUDSON VALLEY/WRN NEW ENGLAND...
CONTRIBUTING TO THE AMPLIFICATION OF UPPER TROUGH ACROSS NEW
ENGLAND/NEW BRUNSWICK/NOVA SCOTIA.

AT THE SURFACE...LOW PRESSURE OVER ERN MT WILL DEEPEN IN RESPONSE TO
INCREASING HEIGHT FALLS MENTIONED ABOVE WITH CYCLONE DEVELOPING INTO
WRN ND BY 09/12Z. THIS SYSTEM WILL BE ATTENDED BY A COLD FRONT
WHICH WILL MOVE THROUGH THE NRN HIGH PLAINS. ELSEWHERE...A COLD
FRONT WILL ADVANCE SEWD THROUGH THE ST. LAWRENCE VALLEY INTO NEW
ENGLAND IN CONJUNCTION WITH AMPLIFYING UPPER TROUGH.

...NRN HIGH PLAINS...

SELY LOW-LEVEL FLOW WILL GRADUALLY STRENGTHEN TODAY OWING TO
DEEPENING LEE CYCLONE WITH BOUNDARY LAYER DEWPOINTS INCREASING
THROUGH THE 50S BENEATH AN EML/STEEP LAPSE RATE PLUME PRECEDING
PACIFIC NW SYSTEM. LATEST MODEL GUIDANCE REMAINS CONSISTENT IN
SUGGESTING AN INCREASED LIKELIHOOD FOR STORM DEVELOPMENT BETWEEN
08/21-09/00Z N/NW OF SURFACE LOW WHERE CONVERGENCE/UPSLOPE FLOW IS
ENHANCED. MORE ISOLATED STORMS WILL BE POSSIBLE AT THIS TIME SWD
ALONG LEE TROUGH INTO FAR ERN WY/WRN SD. LOCAL ENVIRONMENT BY LATE
AFTERNOON/EARLY EVENING WILL BE CHARACTERIZED BY MLCAPE OF 1000-2500
J/KG AND VERTICALLY VEERING WIND PROFILES WITH 35-50 KT DEEP-LAYER
SHEAR. AS SUCH...SETUP WILL FAVOR SUPERCELLS AS THE INITIAL STORM
MODE WITH A RESULTANT RISK FOR LARGE HAIL AND DAMAGING WINDS. WHILE
A TORNADO IS POSSIBLE...A MORE ROBUST THREAT WILL BE LIMITED BY
RELATIVELY HIGH LCL HEIGHTS OWING TO SIZABLE T-TD SPREADS.

UPSCALE GROWTH OF STORMS INTO AN MCS IS POSSIBLE BY MID-LATE EVENING
OVER ERN MT WITH A RISK FOR DAMAGING WINDS AND HAIL CONTINUING
TONIGHT INTO WRN ND.

...NERN U.S...

DESPITE MODEST BOUNDARY LAYER MOISTURE /I.E. DEWPOINTS IN THE
50S/...COOLING MIDLEVEL TEMPERATURES AND DAYTIME HEATING WILL
CONTRIBUTE TO AIR MASS DESTABILIZATION WITH MLCAPE VALUES
APPROACHING 500-1000 J/KG. FORCING/HEIGHT FALLS ASSOCIATED WITH THE
AMPLIFYING UPPER SYSTEM WILL GIVE RISE TO WIDELY SCATTERED TSTMS
THIS AFTERNOON WITHIN AN ENVIRONMENT OF GRADUALLY STRENGTHENING DEEP
LAYER SHEAR. GIVEN THE POTENTIAL FOR MODERATE INSTABILITY AND
RELATIVELY COOL THERMODYNAMIC PROFILES...A FEW SEVERE STORMS WILL BE
POSSIBLE WITH A RISK FOR LOCALLY DAMAGING WINDS AND SEVERE HAIL INTO
THIS EVENING.

...UPPER GREAT LAKES...

GLANCING INFLUENCE OF MIDLEVEL PERTURBATION AND SUSTAINED LOW-LEVEL
WAA ARE EXPECTED TO CONTRIBUTE TO A SLOW INCREASE IN STORM COVERAGE
THROUGH THE PEAK OF THE DIURNAL HEATING CYCLE. INITIALLY ELEVATED
STORMS MAY BECOME PROGRESSIVELY MORE ROOTED IN A WARMING/MOISTENING
BOUNDARY LAYER THIS AFTERNOON WHERE MLCAPE WILL INCREASE TO
1000-2000 J/KG. KINEMATIC ENVIRONMENT WILL FEATURE A VERTICALLY
VEERING WIND PROFILE WITH 35-45 KT OF DEEP NWLY SHEAR WHICH WILL
SUPPORT ROTATING/SUSTAINED UPDRAFTS. DAMAGING WINDS AND LARGE HAIL
WILL BE THE PRIMARY HAZARDS THOUGH A TORNADO IS POSSIBLE OWING TO
THE PRESENCE OF A 30 KT SWLY LLJ AND RESULTANT ENHANCEMENT OF
LOW-LEVEL SHEAR.

...CNTRL/SRN FL PENINSULA...

12Z TAMPA/MIAMI/KEY WEST SOUNDINGS INDICATE THE PRESENCE OF A VERY
MOIST BOUNDARY LAYER /I.E. DEWPOINTS IN THE LOW-MID 70S AND LOWEST
100-MB MEAN-MIXING RATIOS OF 16-17+ G PER KG/ WHICH IS ALREADY
CONTRIBUTING TO A MODERATELY UNSTABLE ENVIRONMENT WITH MLCAPE OF
1500-2500 J/KG. ONGOING STORMS SHOULD FURTHER INCREASE IN AREAL
COVERAGE TODAY...FOCUSED ALONG DEVELOPING SEA BREEZE CIRCULATIONS
AND SYNOPTIC FRONT STALLED ACROSS THE AREA. GIVEN THE VERY MOIST
ENVIRONMENT...SOME POTENTIAL WILL EXIST FOR LOCALLY DAMAGING WIND
GUSTS OWING TO WATER LOADING EFFECTS.

..MEAD/ROGERS.. 06/08/2012

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