Jul 13, 2012 1300 UTC Day 1 Convective Outlook | |
Updated: Fri Jul 13 13:01:32 UTC 2012 | |
Probabilistic to Categorical Outlook Conversion Table |
Categorical Graphic |
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Probabilistic Tornado Graphic |
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. |
Probabilistic Damaging Wind Graphic |
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. |
Probabilistic Large Hail Graphic |
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. |
SPC AC 131257 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0757 AM CDT FRI JUL 13 2012 VALID 131300Z - 141200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE INTERIOR PACIFIC NW/NRN RCKYS... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MO VLY NE INTO THE UPR MS VLY... ...SYNOPSIS... WHILE THE MAIN BELT OF THE WLYS WILL REMAIN IN CANADA...TWO TROUGHS OVER THE LWR 48 WILL SERVE TO FOCUS TSTM POTENTIAL OVER THE U.S. THIS PERIOD. THE FIRST TROUGH...ALONG THE W CST...CONSISTS OF A CLOSED LOW THAT SHOULD REMAIN STNRY OVER WRN WA...WITH AN ELONGATED SRN MEMBER EXTENDING THROUGH THE GRT BASIN TO THE LWR CO VLY. FARTHER E...BEYOND A RIDGE OVER THE RCKYS...A SIMILAR BUT WEAKER PAIR OF DISTURBANCES WILL EXIST OVER THE MS VLY. THE NRN MEMBER OF THIS PAIR SHOULD MOVE SLOWLY E ACROSS MN...WHILE THE SRN ONE REMAINS QSTNRY OVER E TX/WRN LA. ...NRN RCKYS TODAY/TNGT... WRN WA UPR LOW IS EXPECTED TO REMAIN STNRY OR PROGRESS ONLY VERY SLOWLY E THIS PERIOD AS A SERIES OF WEAKER DISTURBANCES MOVE NNE ACROSS ERN ORE IN CORRIDOR OF 25+ KT SSWLY MID LVL FLOW ON ITS ERN FRINGE. WITH LOW LVL MOISTURE CONTINUING TO PERSIST ACROSS NRN WA INTO NRN ID/NW MT /SFC DEWPOINTS IN THE UPR 50S F/...AND WITH RELATIVELY COOL /AOB MINUS 10 C AT 500 MB/ MID LVL TEMPS CONTINUING NEAR UPR LOW...POTENTIAL WILL EXIST FOR A FEW STRONG TO SVR STORMS GIVEN LIKELIHOOD FOR STRONG SFC HEATING/STEEPENING LOW LVL LAPSE RATES BENEATH ZONE OF UPR DIVERGENCE IN NE QUADRANT OF LOW. SUFFICIENT SHEAR ALSO WILL BE PRESENT FOR SUPERCELLS WITH LARGE HAIL/LOCALLY DMGG WIND...ESPECIALLY OVER NRN WA AND PERHAPS NRN ID/NWRN MT. A FEW ELEVATED STORMS POSING A THREAT FOR HAIL MAY SPREAD W TOWARD THE SEATTLE AREA GIVEN PERSISTENT ELY 700 MB FLOW/STEEP MID LVL LAPSE RATES N OF UPR LOW. ...MID MO VLY TO UPR MS VLY THIS AFTN/EVE... SLOWLY-MOVING UPR TROUGH WILL CONTINUE E INTO NRN/CNTRL MN TODAY...WITH AN ASSOCIATED AREA OF LOW LVL WAA EXTENDING SE INTO TOWARD THE MID MS VLY. AS YESTERDAY...SCTD AREAS OF TSTMS SHOULD FORM/INCREASE WITH DAYTIME HEATING BOTH WITHIN THE TROUGH AND ALONG WEAK SFC REFLECTION/WIND SHIFT IN RELATIVELY WEAKLY-CAPPED ENVIRONMENT. BOTH LOW LVL CONVERGENCE AND DEEP SHEAR SHOULD REMAIN WEAK. BUT SUFFICIENT INSTABILITY /MAINLY DUE TO RELATIVELY COOL MID LVL TEMPS/ SHOULD EXIST TO SUPPORT A FEW LONGER-LIVED MULTICELLS CAPABLE OF HAIL AND POSSIBLY LOCALLY DMGG WIND. ...SWRN U.S TODAY/TNGT... SRN CA UPR LOW/TROUGH EXPECTED TO FURTHER ELONGATE S-N ACROSS THE LWR CO VAL TODAY...ALLOWING MOISTURE TO CONTINUE SPREADING N ACROSS ERN NV AND UT. PW VALUES AOA 1.5 INCHES SHOULD PREVAIL FROM SW AZ NWD INTO SE CA/SRN NV...WITH VALUES ABOVE 1.0 INCH EXTENDING AS FAR N AS SALT LAKE CITY. MODEST...INCREASINGLY UNIDIRECTIONAL SLY FLOW AND THERMODYNAMIC PROFILES SUPPORTIVE OF SCTD TO NUMEROUS SHOWERS AND TSTMS...ESPECIALLY OVER THE CO RVR VLY...MAY YIELD ISOLD STRONG DOWNBURSTS GIVEN INCREASING WATER LOADING. ...NRN NEW ENGLAND THIS AFTN... A WEAK SHORT-WAVE TROUGH WILL GLANCE NRN ME LATER TODAY...ON SRN FRINGE OF MODEST WLY JET CROSSING SE QUE. COMBINATION OF STRONG SFC HEATING...MODEST MOISTURE /SFC DEWPOINTS IN THE UPR 50S F/...AND WEAK CONVERGENCE ALONG LOW LVL WIND SHIFT/FRONT MAY SUPPORT WDLY SCTD AFTN/EARLY EVE STORMS. 25-30 KT MID LVL WLY FLOW WILL LIMIT MAGNITUDE OF DEEP SHEAR. BUT GIVEN STEEPENING LOW LVL LAPSE RATES...SETUP COULD YIELD A FEW MULTICELLS WITH GUSTY WINDS AND MARGINALLY SVR HAIL. ..CORFIDI/ROGERS.. 07/13/2012 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z