Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes 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.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
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SPC AC 251618 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1118 AM CDT TUE JUN 25 2013 VALID 251630Z - 261200Z ...THERE IS A SLGT RISK OF SVR TSTMS TODAY INTO TONIGHT ACROSS THE SOUTHERN GREAT LAKES REGION AND OHIO VALLEY INTO THE NORTHEAST...AND ACROSS PARTS OF THE NORTHERN PLAINS SOUTHEASTWARD INTO THE MID MISSOURI AND MIDDLE MISSISSIPPI VALLEYS... ...SYNOPSIS... A STRONG MID-LATITUDE PACIFIC JET CONTINUES TO NOSE INLAND ACROSS THE NORTH CENTRAL PACIFIC COAST AND NORTHERN INTERMOUNTAIN REGION. THIS BELT OF FLOW HAS BEEN GENERALLY ZONAL...BUT MODELS SUGGEST SIGNIFICANT AMPLIFICATION WITHIN THIS REGIME LATER TODAY INTO TOMORROW. A SUBTROPICAL HIGH OVER THE NORTHERN MEXICAN AND SOUTHERN U.S. PLATEAU REGION IS EXPECTED TO EXPAND...WITH RIDGING BUILDING NORTHWARD THROUGH THE ROCKIES...WHILE UPPER TROUGHING DEEPENS UPSTREAM...ACROSS THE EAST CENTRAL PACIFIC. EAST OF THE PLAINS...MID/UPPER HEIGHT FALLS ARE EXPECTED TO COMMENCE...MOST SUBSTANTIVELY...THOUGH STILL SOMEWHAT WEAK...ACROSS PARTS OF THE GREAT LAKES AND UPPER OHIO VALLEY INTO THE NORTHEAST. WITHIN A REGIME TRANSITIONING FROM BROADLY ANTICYCLONIC TO BROADLY CYCLONIC...A NUMBER OF EMBEDDED SMALLER SCALE IMPULSES ARE EXPECTED GRADUALLY DEVELOP EAST SOUTHEAST OF THE UPPER MIDWEST AND GREAT LAKES REGION TODAY. A BELT OF STRONGER WESTERLY LOWER/MID TROPOSPHERIC FLOW...ON THE ORDER OF 30-40+ KT...IS EXPECTED TO ACCOMPANY THIS FEATURE ACROSS PARTS OF THE SOUTHERN GREAT LAKES REGION AND UPPER OHIO VALLEY...THROUGH NORTHERN MID ATLANTIC COASTAL AREAS AND SOUTHERN NEW ENGLAND. VERY WARM AND STRONGLY CAPPING ELEVATED MIXED LAYER AIR WHICH HAS ADVECTED EASTWARD ACROSS MUCH OF THE PLAINS...THE UPPER MIDWEST...AND PARTS OF THE LOWER OHIO VALLEY DOES NOT APPEAR LIKELY TO MAKE FURTHER EASTWARD PROGRESS TODAY. AND...IN FACT...CONVECTIVE OVERTURNING AND MID-LEVEL COLD ADVECTION MAY BEGIN STABILIZING LAPSE RATES ACROSS THE NORTHERN PLAINS LATE THIS AFTERNOON AND TONIGHT...WHILE THE ELEVATED MIXED LAYER HOLDS FIRM ACROSS/SOUTH AND WEST OF THE CENTRAL PLAINS AND MIDDLE MISSISSIPPI VALLEY. GIVEN THE PRESENCE OF CONTINUING SEASONABLE MOISTURE...WEAK/ WEAKENING INHIBITION ACROSS MUCH OF THE GREAT LAKES/OHIO VALLEY AND NORTHEAST PROBABLY WILL ALLOW FOR CONSIDERABLE THUNDERSTORM ACTIVITY THIS AFTERNOON AND EVENING. THUNDERSTORM PROBABILITIES ALSO APPEAR LIKELY TO BECOME RELATIVELY HIGH DURING THE PEAK AFTERNOON HEATING ACROSS THE SOUTHEAST STATES...INCLUDING THE FLORIDA PENINSULA. ...GREAT LAKES/OHIO VALLEY INTO THE NORTHEAST... MODERATELY LARGE MIXED LAYER CAPE...ON THE ORDER OF 1000-2000+ J/KG ...IS EXPECTED TO DEVELOP WITH DAYTIME HEATING ACROSS MUCH OF THE REGION. HIGHEST VALUES ARE EXPECTED ACROSS THE OHIO VALLEY INTO THE SOUTHERN/LOWER GREAT LAKES REGION...AND PORTIONS OF THE NORTHERN MID ATLANTIC COAST STATES...WHERE THE AFOREMENTIONED BELT OF ENHANCED LOW/MID-LEVEL FLOW MAY CONTRIBUTE TO SEVERAL STORM CLUSTERS WITH COLD POOLS CAPABLE OF PRODUCING SWATHS OF POTENTIALLY DAMAGING WIND GUSTS. A BELT OF STRONGER MID/UPPER FLOW AND FORCING FOR UPWARD VERTICAL MOTION...ASSOCIATED WITH A SHORT WAVE IMPULSE PROGRESSING ACROSS THE EASTERN CANADIAN PROVINCES...MAY ALSO ENHANCE CONVECTIVE POTENTIAL ACROSS PARTS OF CENTRAL/NORTHERN MAINE...WHERE ISOLATED SUPERCELLS WITH THE RISK FOR LARGE HAIL AND LOCALIZED STRONG WIND GUSTS MAY NOT BE OUT OF THE QUESTION. ...NORTHERN PLAINS INTO THE MID MO/MID MS VALLEYS... DIFLUENT AND DIVERGENT HIGH LEVEL FLOW APPEARS LIKELY TO BECOME FOCUSED ACROSS NORTH DAKOTA LATE THIS AFTERNOON OR EARLY EVENING. THIS IS EXPECTED TO COINCIDE WITH THE NORTHEASTWARD PROGRESSION OF A MID-LEVEL TROUGH OUT OF THE NORTHERN ROCKIES... BEFORE IT TURNS EASTWARD...THEN SOUTHEASTWARD TOWARD THE UPPER MISSISSIPPI VALLEY. IT SEEMS PROBABLE THAT THIS WILL WEAKEN INHIBITION SUFFICIENTLY FOR CONVECTIVE DEVELOPMENT IN THE PRESENCE OF THERMODYNAMIC PROFILES QUITE SUPPORTIVE OF SEVERE HAIL AND WIND POTENTIAL. MORE UNCERTAINTY EXISTS CONCERNING THE STRENGTH OF VERTICAL SHEAR...BUT THE EVOLUTION OF AN ORGANIZED STORM CLUSTER DOES NOT APPEAR OUT OF THE QUESTION. THE EXTENT AND LOCATION OF RELATIVELY HIGHER SEVERE PROBABILITIES REMAIN MORE UNCLEAR ACROSS PARTS OF THE MID MISSOURI AND MIDDLE MISSISSIPPI VALLEYS. THE PRIMARY FOCUS WOULD SEEM TO BE NORTHEAST OF A SURFACE LOW...NEAR THE INTERSECTION OF A SURFACE TROUGH AND REMNANTS OF CONVECTIVE OUTFLOW...JUST EAST OF THE MID MISSOURI VALLEY AT EARLY EVENING. BUT MID-LEVEL INHIBITION COULD REMAIN SUPPRESSIVE TO CONVECTIVE DEVELOPMENT THROUGH THE ONSET OF LATE EVENING BOUNDARY LAYER COOLING/STABILIZATION. ..KERR/COHEN.. 06/25/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z