DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1243 AM CDT SUN AUG 07 2016 VALID 071200Z - 081200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS N-CNTRL MT... ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PORTIONS OF NRN HIGH PLAINS...CNTRL HIGH PLAINS...AND CNTRL PLAINS... ...SUMMARY... SEVERE THUNDERSTORMS CAPABLE OF DAMAGING WIND GUSTS AND HAIL ARE POSSIBLE OVER WESTERN AND CENTRAL MONTANA THIS AFTERNOON. AFTERNOON STORMS MAY ALSO PRODUCE A FEW LOCALLY STRONG WIND GUSTS ACROSS PORTIONS OF THE CENTRAL PLAINS AND CENTRAL HIGH PLAINS. ...SYNOPSIS... COMPACT SHORTWAVE TROUGH CURRENTLY MOVING THROUGH CNTRL CA WILL CONTINUE THROUGH THE SRN AND ERN PERIPHERY OF THE UPPER CYCLONE CENTERED JUST OFF THE PACIFIC NW COAST. RESULTING NEWD TRAJECTORY WILL TAKE THIS SHORTWAVE ACROSS THE NRN GREAT BASIN AND INTO THE NRN ROCKIES BY THE AFTERNOON. FARTHER E...A SERIES OF SHORTWAVE TROUGHS WILL TRAVERSE THE SRN PERIPHERY OF A LARGER TROUGH EXTENDING ACROSS QUEBEC...TRACKING EWD THROUGH SRN QUEBEC AND NRN NEW ENGLAND. SURFACE PATTERN AT 12Z WILL LIKELY FEATURE A DIFFUSE COLD FRONT STRETCHING FROM THE MID-ATLANTIC WWD ACROSS NRN PORTION OF THE SOUTHEAST STATES. THIS BOUNDARY WILL CONTINUE NWWD THROUGH OK AND INTO SW KS BUT ITS POSITION WILL BE DETERMINED BY OUTFLOW FROM MCS CURRENTLY MOVING ACROSS WRN KS. CURRENT EXPECTATION IS FOR THE BOUNDARY TO REMAIN MOSTLY STATIONARY THROUGHOUT THE DAY. ELSEWHERE...LEE TROUGHING WILL DEEPEN ACROSS THE HIGH PLAINS WHILE HIGH PRESSURE SLOWLY MOVES EWD OVER THE GREAT LAKES. ...CNTRL PLAINS... ONGOING CONVECTION ACROSS THE CNTRL PLAINS INTRODUCES SOME UNCERTAINTY REGARDING WHERE THE SVR POTENTIAL ACROSS THE REGION WILL MATERIALIZE. CURRENT EXPECTATION IS FOR THE OUTFLOW BOUNDARY ASSOCIATED WITH THIS CONVECTION TO EXIST NEAR THE OK/KS BORDER...ACTING AS THE EFFECTIVE FRONT. DIURNAL HEATING AND RESULTING DESTABILIZATION IN THE PRESENCE OF THIS BOUNDARY WILL LIKELY PROVIDE THE IMPETUS FOR CONVECTIVE INITIATION. VERTICAL SHEAR WILL BE WEAK BUT MODERATE INSTABILITY AND A MOIST LOW-LEVEL AIRMASS WILL SUPPORT STRONG UPDRAFTS CAPABLE OF PRECIPITATION LOADING...WITH A RESULTING THREAT FOR ISOLATED DAMAGING WIND GUSTS. ...CNTRL HIGH PLAINS... TSTMS ARE EXPECTED DEVELOP OVER THE HIGHER TERRAIN AND SLOWLY MOVE EWD INTO THE ADJACENT HIGH PLAINS. DIURNAL HEATING AND MODEST MOISTURE ADVECTION ASSOCIATED WITH UPSLOPE FLOW WILL CONTRIBUTE TO DESTABILIZATION ACROSS THE HIGH PLAINS...WITH THE POTENTIAL FOR A FEW OF THE STORMS INITIATED OVER THE HIGH TERRAIN TO PERSIST AS MOVE INTO THE REGION. VERTICAL SHEAR WILL BE WEAK BUT THE DEEPLY MIXED BOUNDARY LAYER AND HIGH CLOUD BASES COULD RESULT IN A FEW STRONG WIND GUSTS WITH THE MORE PERSISTENT STORMS. ...NRN ROCKIES/NRN HIGH PLAINS... LOW-LEVEL MOISTURE ADVECTION IS EXPECTED ACROSS THE REGION...WITH DEWPOINTS DURING THE MID-AFTERNOON LIKELY RANGING FROM THE LOW 50S OVER THE NRN HIGH PLAINS TO THE MID TO UPPER 50S ACROSS ERN MT. THIS MOISTURE ADVECTION WILL SUPPORT MODEST INSTABILITY AND...IN TANDEM WITH A FAVORABLY TIMED SHORTWAVE TROUGH...IS EXPECTED TO RESULT IN AT LEAST WIDELY SCATTERED TSTMS. ADDITIONALLY...SELY SURFACE WIND COUPLED WITH INCREASING MID-LEVEL FLOW ALOFT WILL RESULT IN VERTICAL SHEAR PROFILES FAVORABLE FOR ORGANIZED STORMS. GIVEN THE MIXED BOUNDARY LAYER AND HIGH CLOUD BASES...DAMAGING WIND GUSTS ARE PROBABLE WITH ANTICIPATED COVERAGE HIGH ENOUGH TO MERIT 15-PERCENT WIND PROBABILITIES. SVR HAIL COVERAGE WILL BE LIMITED BY LOW INSTABILITY...ALTHOUGH SOME ISOLATED OCCURRENCES OF SVR HAIL ARE STILL POSSIBLE. ..MOSIER/PICCA.. 08/07/2016Read more
from SPC Forecast Products http://ift.tt/s7Jkvo
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