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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 041238 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0738 AM CDT WED SEP 04 2013 VALID 041300Z - 051200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF WA...ORE...AND ID.... ...WA/ORE/ID... A BROAD UPPER RIDGE IS IN PLACE OVER THE ROCKIES AND SOUTHERN PLAINS STATES TODAY...WHILE UPPER TROUGHS AFFECT THE NORTHEAST STATES AND THE PACIFIC NORTHWEST. SEVERAL PERTURBATIONS ARE FORECAST TO ROTATE AROUND A PERSISTENT UPPER LOW OFF THE WA/ORE COAST. THIS ENERGY WILL BEGIN TO AFFECT PORTIONS OF EASTERN WA/ORE AND MUCH OF ID BY MID/LATE AFTERNOON. RECENT SURFACE OBSERVATIONS AND 12Z RAOB DATA FROM LKN/BOI VERIFY AN AXIS OF SUBSTANTIAL MOISTURE IN THIS AREA WITH DEWPOINTS IN THE 50S AND PWAT VALUES OF 1.00-1.30 INCHES. STRONG DAYTIME HEATING WILL YIELD MLCAPE VALUES OVER 1000 J/KG WITH LITTLE CAP. THE RESULT WILL BE SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT OVER PARTS OF EASTERN ORE AND SOUTHWEST ID BY LATE AFTERNOON. THESE STORMS WILL SPREAD NORTHWARD ACROSS THE SLIGHT RISK AREA DURING THE EVENING. WHILE THE COVERAGE OF SEVERE STORMS IS IN QUESTION...IT APPEARS THAT STEEP LOW/MID LEVEL LAPSE RATES AND SUFFICIENT VERTICAL SHEAR WILL BE IN PLACE. ORGANIZED MULTICELL AND ISOLATED SUPERCELL STORMS ARE POSSIBLE...CAPABLE OF LARGE HAIL AND DAMAGING WINDS. ...MT AND WESTERN DAKOTAS... MORNING WATER VAPOR IMAGERY SHOWS A WEAK UPPER FEATURE MOVING ACROSS WESTERN WY. THIS SYSTEM IS FAVORABLY TIMED TO MOVE INTO THE HIGH PLAINS OF EASTERN MT/NORTHEAST WY AND THE WESTERN DAKOTAS LATE THIS AFTERNOON AND EVENING. EASTERLY LOW LEVEL WINDS WILL MAINTAIN 50S SURFACE DEWPOINTS AND MLCAPE VALUES OF 500-1500 J/KG. WEAK FORCING IS EXPECTED TO LIMIT THE AREAL COVERAGE OF INTENSE STORMS. HOWEVER...PARAMETERS APPEAR FAVORABLE FOR SOME RISK OF HAIL AND WIND IN THE STRONGEST STORMS THIS EVENING. ..HART/SMITH.. 09/04/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z |