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| Probabilistic Tornado Graphic | |||||||||
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| Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point. |
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| Probabilistic Damaging Wind Graphic | |||||||||
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| Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point. |
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| Probabilistic Large Hail Graphic | |||||||||
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| Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point. |
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SPC AC 170531 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1231 AM CDT WED JUL 17 2013 VALID 171200Z - 181200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM NRN NY EWD ACROSS NEW ENGLAND... ...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN WA INTO WRN MT... ...SYNOPSIS... A COMPACT SHORTWAVE TROUGH WILL MOVE NEWD ACROSS THE PACIFIC NW EARLY IN THE DAY...AND INTO NWRN MT BY AFTERNOON. LIFT WITH THIS FEATURE IS LIKELY TO RESULT IN SCATTERED SEVERE THUNDERSTORMS. TO THE E...AN UPPER HIGH WILL REMAIN SITUATED ACROSS THE MID MS AND OH VALLEYS WITH A BROAD UPPER TROUGH TO THE N ACROSS ONTARIO AND QUEBEC. THIS TROUGH WILL RESULT IN AN INCREASE IN WIND SHEAR AND FORCING FOR SEVERE STORMS ACROSS MAINLY NRN NEW ENGLAND. ELSEWHERE...AMPLE MOISTURE WILL REMAIN ACROSS THE SERN STATES...AND DAYTIME HEATING SHOULD AGAIN YIELD SCATTERED STRONG STORMS WITH LOCALIZED WIND AND HAIL. ...ERN WA INTO WRN MT... EARLY MORNING THUNDERSTORMS ARE EXPECTED TO FORM OVER ERN WA AS THE SHORTWAVE TROUGH INCREASES LIFT AND COOLING ALOFT. FORECAST SOUNDINGS SHOW THE MOISTURE WILL BE ELEVATED ABOVE A RELATIVELY WARM AND DRY BOUNDARY LAYER...WHICH SHOULD MAXIMIZE EVAPORATIVE COOLING IN THE SUBCLOUD LAYER. EFFECTIVE SHEAR WILL BE FAVORABLE FOR SUPERCELLS WITH INCREASING SPEED SHEAR WITH HEIGHT. DAMAGING WINDS WILL BE INCREASINGLY PROBABLE AS STORM COVERAGE INCREASES OVER WRN MT. ...NRN NY INTO NRN NEW ENGLAND... WEAK SHORTWAVE RIDGING WILL BE IN PLACE EARLY...WHILE SWLY LOW LEVEL FLOW HELPS TO TRANSPORT A WARM AND MOIST AIR MASS NEWD. LIFT ASSOCIATED WITH WARM ADVECTION COULD RESULT IN ISOLATED THUNDERSTORMS ACROSS MAINE BY MIDDAY...AND THESE STORMS WILL BE CAPABLE OF MARGINALLY SEVERE HAIL AND HEAVY RAIN. UPSTREAM INTO QUEBEC...A BROKEN LINE OF CELLS WILL EXIST ALONG THE ADVANCING COLD FRONT...WHICH SHOULD APPROACH THE U.S. BORDER AROUND 00Z. THESE STORMS WILL POSE A SEVERE WIND AND PERHAPS HAIL THREAT AS THEY TRAVERSE NEW ENGLAND DURING THE EVENING...AND WILL LIKELY WEAKEN AS THEY APPROACH MORE STABLE AIR NEAR THE COAST. ...NERN MN EWD ACROSS NRN WI AND INTO UPPER MI... AIDED BY STRONG HEATING...SCATTERED STORMS ARE EXPECTED TO DEVELOP BY AFTERNOON FROM CNTRL MN EWD ACROSS NRN WI AND THE U.P. OF MICHIGAN ALONG A WEAK BOUNDARY. FLOW ALOFT WILL GENERALLY BE PARALLEL TO THE BOUNDARY...WITH TRAINING ECHOES POSSIBLE. EFFECTIVE SHEAR WILL BE MARGINAL FOR ORGANIZED SEVERE STORMS...AND FLOW ALOFT WILL SLIGHTLY VEER WITH NEUTRAL HEIGHT CHANGES ALOFT. MARGINALLY SEVERE HAIL AND WIND WILL BE POSSIBLE WITH THE STRONGEST STORMS...BUT COVERAGE MAY NOT MEET SLIGHT RISK CRITERIA. ...SERN STATES... MODERATE INSTABILITY WILL AGAIN DEVELOP BY LATE MORNING/EARLY AFTERNOON WITH AMPLE MOISTURE IN PLACE. WITH LITTLE HEATING REQUIRED TO ERODE CIN...STORMS MAY FORM RELATIVELY EARLY ACROSS WRN VA/NC AND INTO NRN GA...AND THEN FARTHER E ACROSS SC. LOCALLY STRONG TO SEVERE DOWNBURSTS WILL BE POSSIBLE...ALONG WITH MARGINAL HAIL. ..JEWELL/BUNTING.. 07/17/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z |