DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0758 AM CDT SUN JUN 05 2016 VALID 051300Z - 061200Z ...THERE IS AN ENH RISK OF SVR TSTMS ACROSS PARTS OF PA/NJ TO NC... ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF NY TO GA... ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE EASTERN STATES... ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS CO/NM... ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS EAST/NORTHEAST MN AND WI... ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS NORTHERN CA/NV INTO ORE/ID... ...SUMMARY... SEVERAL STORM CLUSTERS ARE ANTICIPATED FROM NEW YORK TO GEORGIA THIS AFTERNOON AND EVENING. THUNDERSTORM-RELATED WIND DAMAGE WILL BE THE PRIMARY HAZARD...ESPECIALLY OVER THE MID-ATLANTIC STATES AND NORTH CAROLINA. ...SYNOPSIS... A SHORTWAVE TROUGH OVER THE GREAT LAKES WILL SHIFT EAST-NORTHEASTWARD AND REACH WESTERN QUEBEC BY EARLY MONDAY...AS AN UPSTREAM IMPULSE DIGS SOUTHEASTWARD ACROSS THE CANADIAN PRAIRIE PROVINCES INTO THE UPPER MIDWEST. A SURFACE CYCLONE WILL DEEPEN AS IT TRACKS FROM THE CENTRAL GREAT LAKES TOWARDS JAMES BAY. IN THE SOUTHWEST...AN UPPER-LEVEL RIDGE WILL DAMPEN AHEAD OF A SLOW-MOVING UPPER LOW OVER NORTHERN CA/NV. ...EASTERN STATES... STRENGTHENING MID/HIGH-LEVEL CYCLONIC FLOW IS EXPECTED TODAY OVER MUCH OF THE MID-ATLANTIC/NORTHEAST STATES TODAY IN ASSOCIATION WITH THE SHORTWAVE TROUGH MOVING OVER THE LOWER GREAT LAKES TOWARD QUEBEC. A COLD FRONT WILL CONTINUE GENERALLY EASTWARD TODAY ACROSS THE MIDDLE/UPPER OH RIVER VALLEY...REACHING THE COASTAL NORTHEAST/MID-ATLANTIC STATES BY EARLY MONDAY MORNING. AHEAD OF THE COLD FRONT...A MOIST AIR MASS WILL CONTINUE TO ADVECT NORTHEASTWARD ACROSS THE MID-ATLANTIC/NORTHEAST STATES...WITH UPPER 60S/LOWER 70S F SURFACE DEWPOINTS INCREASINGLY COMMON AS FAR NORTH AS NY/SOUTHERN NEW ENGLAND. WHILE RELATIVELY RICH MOISTURE WILL INCREASINGLY BE IN PLACE...EARLY-MORNING SATELLITE/RADAR IMAGERY FEATURES RELATIVELY PREVALENT CLOUD COVER AND WIDELY SCATTERED SHOWERS WITHIN THE WARM SECTOR...WITH WEAK LAPSE RATES NOTED IN REGIONAL 12Z OBSERVED SOUNDINGS. THIS CASTS SOME UNCERTAINTY ON THE EXACT DEGREE OF DESTABILIZATION THIS AFTERNOON...BUT EVEN SO...POCKETS OF STRONG INSOLATION AND A MARGINALLY TO MODERATELY UNSTABLE AIR MASS SHOULD LEAD TO INTENSIFYING/INCREASINGLY SURFACE-BASED THUNDERSTORMS THIS AFTERNOON. WITH A STRENGTHENING BELT OF MID-LEVEL /700-500 MB/ WEST-SOUTHWESTERLY WINDS OVERSPREADING THE WARM SECTOR...30-45 KT EFFECTIVE SHEAR WILL SUPPORT ORGANIZED/SUSTAINED AND RELATIVELY FAST-MOVING STORMS. A FEW INITIAL SUPERCELLS MAY OCCUR...BUT AN AMPLE DEGREE OF FORCING FOR ASCENT COMBINED WITH A TENDENCY FOR VEERED LOW-LEVEL WINDS SUGGESTS THAT ACTIVITY SHOULD EVOLVE INTO MULTICELL/LINEARLY BANDED CLUSTERS. DAMAGING WINDS WILL LIKELY BE THE PRIMARY HAZARD...BUT A TORNADO AND/OR MARGINALLY SEVERE HAIL WILL ALSO BE POSSIBLE IN ANY INITIAL OR TRANSIENT SUPERCELL STRUCTURES. ...CO/NM... A SUBTLE MID-LEVEL DISTURBANCE OVER SOUTHWEST WY IN THE PREDAWN HOURS SHOULD CONTINUE SOUTHEASTWARD AND REACH CENTRAL CO/NORTHERN NM THIS AFTERNOON. RELATED FORCING FOR ASCENT/OROGRAPHIC EFFECTS SHOULD CONTRIBUTE TO A STEADY INCREASE OF THUNDERSTORMS THIS AFTERNOON WITHIN A MODESTLY MOIST ENVIRONMENT /MIDDLE 40S TO LOWER 50S F DEWPOINTS/. ISOLATED TO WIDELY SCATTERED STORMS SHOULD INITIALLY FORM OVER THE SANGRE DE CRISTO MOUNTAINS VICINITY THIS AFTERNOON...AND SUBSEQUENTLY SPREAD SOUTH-SOUTHEASTWARD. AS MUCH AS 35 KT OF EFFECTIVE SHEAR WILL SUPPORT SUSTAINED MULTICELLS AND POSSIBLY A WEAK SUPERCELL OR TWO...WITH SEVERE HAIL/LOCALLY STRONG WIND GUSTS A POSSIBILITY THIS AFTERNOON AND EVENING. ...EAST/NORTHEAST MN AND WI... A STRENGTHENING BELT OF MID/HIGH-LEVEL NORTHWESTERLIES WILL BE PREVALENT ACROSS THE UPPER MIDWEST...YIELDING ELONGATED STRAIGHT HODOGRAPHS THIS AFTERNOON. BOUNDARY-LAYER MOISTURE WILL BE LIMITED /40S TO LOWER 50S F DEWPOINTS/ AND BUOYANCY MAY REMAIN MEAGER. HOWEVER...STEEPENING LOW/MID-TROPOSPHERIC LAPSE RATES AMID MID-LEVEL DCVA SHOULD YIELD WIDELY SCATTERED LOW-TOPPED THUNDERSTORM-PRODUCING CONVECTION. SETUP MAY SUPPORT FAST-MOVING CELLS WITH SPORADIC INSTANCES OF MARGINALLY SEVERE HAIL AND LOCALLY DAMAGING WINDS THIS AFTERNOON/EARLY EVENING. ...NORTHERN CA/NV INTO ORE/ID... AN UPPER LOW OVER NORTHERN CA EARLY THIS MORNING WILL CONTINUE TO DRIFT EAST-NORTHEASTWARD TOWARD NORTHERN/CENTRAL NV THROUGH TONIGHT. RELATED DPVA/UPPER-JET EXIT REGION WILL OVERSPREAD NORTHERN PORTIONS OF CA/NV INTO SOUTHERN/EASTERN ORE AND SOUTHERN ID...WITH AN EXPECTED DIURNAL INCREASE IN THUNDERSTORMS WITHIN A RELATIVELY MOIST ENVIRONMENT /0.50-0.70 INCH PRECIPITABLE WATER VALUES/. WHILE LOW/MID-TROPOSPHERIC FLOW WILL BE WEAK /LESS THAN 25 KT/ ON THE NORTH-NORTHEAST PERIPHERY OF THE UPPER LOW...SUFFICIENT MOISTURE/STEEP LAPSE RATES AND WELL-MIXED BOUNDARY LAYER SHOULD SUPPORT SOME DOWNBURST POTENTIAL /AND POSSIBLY SMALL HAIL/ THIS AFTERNOON AND EARLY EVENING. ..GUYER/DEAN.. 06/05/2016Read more
from SPC Forecast Products http://ift.tt/rATNzD
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