May 28, 2013 0600 UTC Day 1 Convective Outlook
Updated: Tue May 28 06:04:37 UTC 2013
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20130528 1200 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20130528 1200 UTC Day 1 Tornado Probabilities 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
20130528 1200 UTC Day 1 Damaging Wind Probabilities 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
20130528 1200 UTC Day 1 Large Hail Probabilities 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.
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 530,006 49,818,593 Chicago, IL...Indianapolis, IN...Detroit, MI...Kansas City, MO...Omaha, NE...
   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

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