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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 280600 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0100 AM CDT TUE MAY 28 2013 VALID 281200Z - 291200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE PLAINS TO THE MIDWEST/GREAT LAKES REGION... ...SYNOPSIS... THE LONGWAVE PATTERN WILL UNDERGO AMPLIFICATION DURING THE PERIOD...HIGHLIGHTED BY AN AMPLIFYING UPPER TROUGH OVER THE CENTRAL/SOUTHERN ROCKIES THIS AFTERNOON/TONIGHT...WITH A STRONG POLAR JET/SECONDARY SHORTWAVE TROUGH ADDITIONALLY APPROACHING THE PACIFIC NORTHWEST/GREAT BASIN. ...MIDWEST/GREAT LAKES TO NORTHEAST STATES... AN MCS OR REMNANTS THEREOF MAY BE LOCATED ACROSS NORTHERN/CENTRAL PORTIONS OF IL/INDIANA AT THE BEGINNING OF THE PERIOD...WITH A POSSIBLE MCV AND/OR EMBEDDED SHORTWAVE TROUGH OTHERWISE LIKELY TO CONTINUE TO SPREAD EAST-NORTHEASTWARD OVER PARTS OF THE MIDWEST/GREAT LAKES REGION TODAY. AS THE BOUNDARY LAYER DESTABILIZES...SURFACE BASED TSTM DEVELOPMENT/INTENSIFICATION SHOULD OCCUR AHEAD OF THE REMNANT MCV/AFOREMENTIONED MID-LEVEL IMPULSE...POTENTIALLY INCLUDING PORTIONS OF LOWER MI/NORTHERN INDIANA EASTWARD INTO NORTHERN OH AND PORTIONS OF PA/WESTERN NY. WHILE MULTICELLS CAPABLE OF MAINLY DAMAGING WINDS/SOME HAIL SHOULD THE PRIMARY HAZARDS...DEEP LAYER/LOW-LEVEL SHEAR WILL BE ADEQUATE FOR SOME SUPERCELLS AND AN ISOLATED TORNADO THREAT. ...EASTERN KS/LOWER MO VALLEY/MIDDLE MS VALLEY... OUTFLOW BOUNDARY FROM OVERNIGHT/EARLY MORNING MCS WILL LIKELY SETTLE SOUTH-SOUTHEASTWARD ACROSS THE REGION TODAY. WHILE SPECIFIC CONFIDENCE IS MODEST AND DETAILS ARE A BIT UNCERTAIN...TSTMS SHOULD REDEVELOP LATER TODAY IN VICINITY OF THIS EFFECTIVE BOUNDARY...SEEMINGLY MOST PROBABLE MID/LATE AFTERNOON INTO THIS EVENING ACROSS AREAS SUCH AS EASTERN KS INTO MO. THIS IS WHERE SOMEWHAT STRONGER HEATING IS MORE LIKELY ON THE WEST-SOUTHWESTERN FRINGE OF THE PROBABLE OUTFLOW REMNANTS. COMBINED WITH A BELT OF MODERATELY STRONG DEEP LAYER SOUTHWESTERLY FLOW...SUSTAINED SEVERE TSTMS INCLUDING MULTICELLS/SOME SUPERCELLS WILL BE POSSIBLE WITH ASSOCIATED POTENTIAL FOR SEVERE HAIL...DAMAGING WINDS...AND PERHAPS A TORNADO OR TWO /MAINLY IN VICINITY OF THE EFFECTIVE FRONT OR REMNANT OUTFLOW/. ...WESTERN OK AND MUCH OF WEST/NORTHWEST TX... AIRMASS WILL DESTABILIZE ALONG/EAST OF THE SOUTHERN HIGH PLAINS DRYLINE THIS AFTERNOON...WITH AT LEAST ISOLATED/WIDELY SCATTERED TSTM DEVELOPMENT PROBABLE ESPECIALLY ACROSS PORTIONS OF THE TX PANHANDLE AND NORTHWEST TX/WESTERN OK. OTHER...PERHAPS A BIT MORE ISOLATED...DEEP CONVECTIVE DEVELOPMENT IS LIKELY TO OCCUR FARTHER SOUTH-SOUTHWEST ACROSS ADDITIONAL PARTS OF WEST/SOUTHWEST TX. OF NOTE...AFTER PEAK HEATING...ADDITIONAL DEVELOPMENT CANNOT BE RULED OUT FARTHER WEST ALONG THE RETREATING DRYLINE DURING THE EVENING OR EVEN LATE NIGHT...PERHAPS AIDED BY THE APPROACHING UPSTREAM TROUGH. REGARDLESS...MODERATE INSTABILITY COMBINED WITH AROUND 35 KT OF EFFECTIVE SHEAR WILL SUPPORT A MIXED MODE OF SUSTAINED MULTICELLS/SUPERCELLS WITH LARGE HAIL/DAMAGING WINDS AS THE PRIMARY HAZARDS...ESPECIALLY DURING THE LATE AFTERNOON/EARLY EVENING HOURS AS STORMS POTENTIALLY MERGE/SPREAD EASTWARD ACROSS NORTHWEST TX/WESTERN OK. ...CENTRAL HIGH PLAINS... AIDED BY A GRADUALLY DEEPENING EASTERN CO SURFACE LOW AND APPROACHING EASTERN GREAT BASIN/CENTRAL ROCKIES SHORTWAVE TROUGH...A LOW-LEVEL UPSLOPE REGIME WILL ADDITIONALLY CONTRIBUTE TO PROBABLE TSTM DEVELOPMENT BY MID/LATE AFTERNOON. THIS INCLUDES THE WY/PARTS OF CO FRONT RANGE INTO WESTERN NEB/SOUTHWEST SD/NORTHEAST CO. AROUND 35 KT OF DEEP LAYER SHEAR COINCIDENT WITH A CORRIDOR OF MODERATE INSTABILITY /1000-2000 J PER KG MLCAPE/ WILL SUPPORT THE POSSIBILITY OF SEVERE CALIBER MULTICELLS/SUPERCELLS CAPABLE OF LARGE HAIL. THE POTENTIAL WILL ALSO EXIST FOR A TORNADO OR TWO AND/OR LOCALIZED WIND DAMAGE...PERHAPS ESPECIALLY BY EARLY EVENING AS DEEP LAYER SHEAR/LOW-LEVEL SOUTHEASTERLY WINDS INCREASE ACROSS THE REGION. AS A WARM ADVECTION REGIME NOCTURNALLY INCREASES...ADDITIONAL STORM DEVELOPMENT WILL BE POSSIBLE A BIT FARTHER EAST ACROSS PORTIONS OF WESTERN/NORTHERN KS INTO NEB THROUGH EARLY/MID EVENING. AT LEAST ISOLATED BOUTS OF LARGE HAIL WILL BE A POSSIBILITY. ..GUYER/GRAMS.. 05/28/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z |