Jun 30, 2014 1300 UTC Day 1 Convective Outlook
Updated: Mon Jun 30 12:52:07 UTC 2014 (20140630 1300Z Day 1 shapefile | 20140630 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Public Severe Weather Outlook

The SPC is forecasting ...Severe thunderstorms expected over parts of the Middle-upper Mississippi Valley region later today and tonight....   Please read the latest public statement about this event.  View What is a Watch? clip.

Categorical Graphic
20140630 1300 UTC Day 1 Outlook Graphic
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MODERATE 78,433 14,252,359 Chicago, IL...Des Moines, IA...Aurora, IL...Rockford, IL...Naperville, IL...
SLIGHT 319,398 30,932,425 Indianapolis, IN...Milwaukee, WI...Kansas City, KS...Kansas City, MO...Omaha, NE...
Probabilistic Tornado Graphic
20140630 1300 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.
Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 17,473 1,070,762 Des Moines, IA...Ames, IA...West Des Moines, IA...Ankeny, IA...Urbandale, IA...
15 % 18,417 1,093,591 Des Moines, IA...Ames, IA...West Des Moines, IA...Ankeny, IA...Urbandale, IA...
10 % 33,868 2,092,376 Omaha, NE...Cedar Rapids, IA...Davenport, IA...Waterloo, IA...Iowa City, IA...
5 % 126,423 23,985,491 Chicago, IL...Milwaukee, WI...Kansas City, KS...Kansas City, MO...Madison, WI...
2 % 147,217 15,530,830 Indianapolis, IN...Wichita, KS...St. Louis, MO...Lincoln, NE...Fort Wayne, IN...
Probabilistic Damaging Wind Graphic
20140630 1300 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.
Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 83,871 16,860,925 Chicago, IL...Milwaukee, WI...Madison, WI...Aurora, IL...Rockford, IL...
45 % 63,360 12,965,098 Chicago, IL...Des Moines, IA...Aurora, IL...Rockford, IL...Naperville, IL...
30 % 101,210 14,784,507 Milwaukee, WI...Kansas City, KS...Kansas City, MO...St. Louis, MO...Madison, WI...
15 % 182,383 15,629,122 Indianapolis, IN...Omaha, NE...Wichita, KS...Lincoln, NE...Fort Wayne, IN...
5 % 273,207 34,497,669 Detroit, MI...Columbus, OH...Charlotte, NC...Cleveland, OH...Atlanta, GA...
Probabilistic Large Hail Graphic
20140630 1300 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.
Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 65,399 5,191,599 Kansas City, KS...Kansas City, MO...Omaha, NE...Des Moines, IA...Overland Park, KS...
45 % 42,544 2,375,514 Des Moines, IA...Cedar Rapids, IA...Davenport, IA...Waterloo, IA...Iowa City, IA...
30 % 70,316 6,060,737 Kansas City, KS...Kansas City, MO...Omaha, NE...Wichita, KS...Overland Park, KS...
15 % 278,030 36,151,940 Chicago, IL...Indianapolis, IN...Milwaukee, WI...St. Louis, MO...Lincoln, NE...
5 % 175,600 10,854,978 Detroit, MI...Minneapolis, MN...Toledo, OH...St. Paul, MN...Louisville, KY...
   SPC AC 301252

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0752 AM CDT MON JUN 30 2014

   VALID 301300Z - 011200Z

   ...THERE IS A MDT RISK OF SVR TSTMS CENTRAL...SRN AND ERN IA...NRN
   MO...CENTRAL/NRN IL...EXTREME SRN WI...

   ...THERE IS A SLGT RISK OF SVR TSTMS ELSEWHERE FROM TX PANHANDLE TO
   LOWER MI AND INDIANA...

   ...SUMMARY...
   WIDESPREAD SEVERE THUNDERSTORMS CAPABLE OF LARGE HAIL...TORNADOES
   AND SWATHS OF WIND DAMAGE ARE EXPECTED ESPECIALLY THIS AFTERNOON
   INTO TONIGHT ACROSS MUCH OF THE CORN BELT AND MIDWEST.  MORE WIDELY
   SCATTERED SEVERE STORMS WILL BE POSSIBLE ACROSS THE SOUTH-CENTRAL
   PLAINS.

   ...SYNOPSIS...
   IN MID-UPPER LEVELS...CYCLONE NOW LOCATED OVER MB/ONT BORDER IS FCST
   TO FILL SLOWLY AS IT MOVES EWD ACROSS NORTHERNMOST REACHES OF ONT
   THROUGH REMAINDER PERIOD.  SYNOPTIC-SCALE RIDGE IS FCST TO AMPLIFY
   AS IT MOVES ONSHORE PAC NW TODAY AND ACROSS INTERIOR NWRN STATES AND
   BC OVERNIGHT.  IN BETWEEN THOSE SYNOPTIC FEATURES...SHORTWAVE TROUGH
   WAS APPARENT IN MOISTURE-CHANNEL IMAGERY OVER SRN/ERN MT.  THIS
   PERTURBATION WILL AMPLIFY BUT RETAIN POSITIVE TILT AS IT MOVES ESEWD
   ACROSS NRN PLAINS TODAY...TO NEAR DLH-VTN LINE BY 00Z.  SHORTWAVE
   TROUGH THEN SHOULD PIVOT NEWD AND DEAMPLIFY SOMEWHAT...REACHING ERN
   PORTIONS LS AND UPPER MI BY 12Z.

   AREA OF LOW PRESSURE ANALYZED ON 11Z SFC CHART OVER WRN KS IS
   EXPECTED TO CONSOLIDATE INTO MORE COHERENT SFC LOW DURING DAYLIGHT
   HOURS AND MOVE ENEWD ALONG FRONTAL ZONE TOWARD NERN KS/NWRN
   MO...WHILE TRAILING BOUNDARY MOVES SWD OVER KS AS COLD FRONT.  SAME
   FRONT ALSO WILL MOVE SEWD FROM NEB AND MN ACROSS MUCH OF IA THROUGH
   EVENING.  DRYLINE WILL MIX EWD FROM MORNING POSITION OVER NERN NM
   AND ACROSS PORTIONS OK/TX PANHANDLES AND SWRN KS...WHERE IT WILL
   INTERSECT SWD-MOVING COLD FRONT.

   ...CENTRAL PLAINS TO MID/UPPER MS VALLEY AND LOWER MI...
   REF SPC WWS 371-372 AND RELATED MESOSCALE DISCUSSIONS FOR LATEST
   NEAR-TERM INFO ON CONVECTION FROM WRN NEB TO CENTRAL IA.

   EARLIER TSTMS OVER NRN/ERN IA HAVE PRODUCED PRONOUNCED OUTFLOW
   BOUNDARY THAT APPEARS TO FOCUS SVR POTENTIAL MORE TIGHTLY OVER
   IA...FOR MIDDAY THROUGH AFTN WITHIN MDT RISK AREA...AND WHICH ALSO
   INCREASES RISK OF SIGNIFICANT TORNADOES.  VERY LARGE/DAMAGING HAIL
   STILL IS LIKELY FROM ANY SUSTAINED SUPERCELLS.

   OUTFLOW BOUNDARY HAS BECOME ALIGNED CLOSE TO OR JUST RIGHTWARD OF
   MEAN FLOW...AND MAY BE REINFORCED LOCALLY BY CONVECTION NOW MOVING
   EWD OUT OF ERN NEB.  ANY RELATIVELY DISCRETE SUPERCELL ALONG OR JUST
   N OF THAT BOUNDARY MAY HAVE SUSTAINED ACCESS TO VORTICITY-RICH AND
   DIABATICALLY DESTABILIZED AIR WITH SFC DEW POINTS LOW-MID 70S
   F...CONTRIBUTING TO MLCAPE 4000-5000 J/KG.  SIMILARLY RICH
   MOISTURE/BUOYANCY WILL EXTEND SWD INTO PRECONVECTIVE WARM
   SECTOR...SUPPORTING RAPID GROWTH OF ANY FRONTAL CONVECTION. 
   GREATEST JUXTAPOSITION OF STG BUOYANCY AND DEEP SHEAR THIS AFTN
   SHOULD BE OVER IA...ESPECIALLY WHEN CONSIDERING ENHANCEMENT TO
   LOW-LEVEL SHEAR/SRH RELATED TO OUTFLOW BOUNDARY.

   FARTHER E...AIR MASS WILL TAKE LONGER TO RECOVER FROM MORNING
   CONVECTION/OUTFLOW OVER SRN WI/NRN IL/SWRN LOWER MI AND VICINITY. 
   HOWEVER...SUSTAINED LOW-LEVEL WAA AND AREAS OF AFTN HEATING SHOULD
   ENABLE THAT PROCESS...WITH WAA CONTINUING IN PRECONVECTIVE REGIME
   AFTER 00Z.  AS SUCH...DAMAGING-WIND THREAT WILL EXTEND INTO THESE
   REGIONS DURING EVENING INTO TONIGHT...EXCEPT FOR RELATIVE MIN OVER
   COLD NEAR-SFC MARINE LAYER OF LM.  POTENTIAL EXISTS FOR NEB/IA
   CONVECTION TO EVOLVE UPSCALE AND PRODUCE SWATH OF SIGNIFICANT WIND
   DAMAGE -- PERHAPS WITH ENOUGH LATERAL/AREAL EXTENT TO CLASSIFY AS
   PROGRESSIVE DERECHO -- EWD AS FAR AS SWRN SHORES OF LM.

   DAMAGING WIND AND OCNL LARGE HAIL ALSO ARE LIKELY FROM SQUALL LINE
   EXTENDING SWWD ALONG/AHEAD OF SFC COLD FRONT ACROSS REMAINDER IL AND
   MUCH OF CENTRAL/NRN MO.

   ...SOUTH-CENTRAL PLAINS...
   CONVECTION IS EXPECTED TO DISCRETELY BACKBUILD SWWD INTO THIS REGION
   INVOF FRONT...AND ALSO WITHIN VERY WARM AND STRONGLY MIXING AIR NEAR
   DRYLINE.  HEATING AND LIFT ALONG THOSE BOUNDARIES WILL OVERCOME
   EML-RELATED CAPPING AND TAKE ADVANTAGE OF VERY STEEP MIDLEVEL LAPSE
   RATES...AS WELL AS INCREASING BOUNDARY-LAYER MOISTURE WITH EWD
   EXTENT.  THIS REGIME WILL RESIDE S OF SUBSTANTIAL MID-UPPER LEVEL
   LARGE-SCALE LIFT...WITH 25-35 KT EFFECTIVE SHEAR MAGNITUDES
   INDICATING DOMINANT MULTICELLULAR MODE AND ONLY TRANSIENT SUPERCELL
   POTENTIAL.  DAMAGING GUSTS AND LARGE HAIL WILL BE MAIN
   THREATS...THOUGH A NON-SUPERCELL TORNADO OR TWO CANNOT BE RULED OUT
   WITH COLD-FRONTAL CONVECTION IN ITS EARLY STAGES WHEREVER INTENSE
   UPDRAFTS CAN STRETCH PRE-EXISTING VORTICITY ALONG FRONT.  OVERALL
   SVR POTENTIAL SHOULD DIMINISH THROUGH LATE EVENING.

   ...SRN APPALACHIANS REGION...
   SCATTERED TSTMS SHOULD DEVELOP THIS AFTN OVER THIS AREA AS BOUNDARY
   LAYER DESTABILIZES DIABATICALLY...NEAR AND AHEAD OF WEAK SHORTWAVE
   TROUGH THAT IS MOVING SLOWLY EWD OVER SRN APPALACHIANS ATTM. 
   OUTFLOW/DIFFERENTIAL-HEATING BOUNDARIES FROM ONGOING CONVECTION
   ACROSS THIS REGION MAY FOCUS AFTN/SFC-BASED DEVELOPMENT ON
   MESOSCALE.  FROM THERE...ADDITIONAL OUTFLOWS AND BOUNDARY MERGERS
   MAY SERVE THAT FUNCTION.  WEAK DEEP SHEAR AND SMALL LAPSE RATES
   ABOVE BOUNDARY LAYER WILL LIMIT POTENTIAL FOR ORGANIZED SVR...BUT
   WELL-MIXED SUBCLOUD LAYERS AND WATER-LOADING IN PRECIP CORES SHOULD
   ENABLE RISK FOR DAMAGING GUSTS APCHG SVR LIMITS IN MOST INTENSE
   CORES.

   ..EDWARDS/JIRAK.. 06/30/2014

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