Jul 4, 2015 1630 UTC Day 1 Convective Outlook
Updated: Sat Jul 4 16:30:29 UTC 2015 (20150704 1630Z Day 1 shapefile | 20150704 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20150704 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 233,365 4,406,820 Shreveport, LA...Jackson, MS...Wilmington, NC...Greenville, NC...Jacksonville, NC...
MARGINAL 562,736 40,645,407 Dallas, TX...Fort Worth, TX...Oklahoma City, OK...Virginia Beach, VA...Atlanta, GA...
Probabilistic Tornado Graphic
20150704 1630 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.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
2 % 106,354 615,669 Rapid City, SD...Bismarck, ND...Minot, ND...North Platte, NE...Mandan, ND...
Probabilistic Damaging Wind Graphic
20150704 1630 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.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 233,056 4,409,784 Shreveport, LA...Jackson, MS...Wilmington, NC...Greenville, NC...Jacksonville, NC...
5 % 557,894 40,404,618 Dallas, TX...Fort Worth, TX...Oklahoma City, OK...Virginia Beach, VA...Atlanta, GA...
Probabilistic Large Hail Graphic
20150704 1630 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.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 48,781 181,454 North Platte, NE...
15 % 176,369 1,014,444 Rapid City, SD...Bismarck, ND...Grand Forks, ND...Minot, ND...North Platte, NE...
5 % 475,894 26,028,663 Dallas, TX...Fort Worth, TX...Oklahoma City, OK...Arlington, TX...Plano, TX...
   SPC AC 041630

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1130 AM CDT SAT JUL 04 2015

   VALID 041630Z - 051200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF ND AND MT...

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PART OF THE NRN AND
   CNTRL HIGH PLAINS...

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE GULF
   COAST STATES...

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER ERN NC...

   ...THERE IS A MRGL RISK OF SVR TSTMS FROM THE NRN PLAINS THROUGH
   GULF COAST TO ERN CAROLINAS...

   ...THERE IS A MRGL RISK OF SVR TSTMS OVER A PART OF THE GREAT
   BASIN...

   ...SUMMARY...
   A FEW SEVERE STORMS WITH LARGE HAIL...DAMAGING WINDS...AND POSSIBLY
   A TORNADO ARE EXPECTED OVER PARTS OF THE NORTHERN AND CENTRAL PLAINS
   LATE THIS AFTERNOON AND EVENING. STORMS CAPABLE OF LOCALLY DAMAGING
   WIND AND HEAVY RAIN ARE EXPECTED OVER CENTRAL GULF COAST STATES.
   MORE ISOLATED STRONG TO SEVERE STORMS WILL AFFECT THE SOUTHERN
   PLAINS...GEORGIA...THE CAROLINAS...AND THE GREAT BASIN.

   ...SYNOPSIS...

   A MID TO UPPER-LEVEL LOW WILL TRACK ACROSS NRN PORTIONS OF THE
   CANADIAN PRAIRIE PROVINCES WHILE A RELATED VORTICITY MAXIMUM DIGS
   SWD THROUGH BRITISH COLUMBIA INTO THE PACIFIC NW.  THIS PATTERN
   EVOLUTION WILL DAMPEN A MID-LEVEL RIDGE PRESENT FROM THE GREAT BASIN
   INTO NRN MEXICO...AND EFFECTIVELY FRACTURE THE ERN U.S. LONG-WAVE
   TROUGH INTO SEPARATE AIR STREAMS WITH THE NRN BRANCH UNDERGOING
   SUBSTANTIAL HEIGHT RISES OVER ONTARIO AND QUEBEC.  MEANWHILE A BELT
   OF ENHANCED CYCLONIC FLOW AND COOL MID-LEVEL TEMPERATURES WILL
   PERSIST WITH THE SRN PORTION OF THE RESIDUAL TROUGH OVER THE TN
   VALLEY AND GULF COAST STATES INTO SERN CONUS.  AHEAD OF THE EVOLVING
   CANADIAN UPPER-AIR SYSTEM...A LOW-AMPLITUDE SHORT-WAVE TROUGH WILL
   TRACK FROM THE NRN PLAINS INTO THE UPPER MS VALLEY.

   AT THE SURFACE...A LEE CYCLONE WILL DEEPEN TODAY OVER ERN MT ALONG A
   COLD FRONT SHIFTING SWD INTO THE NRN HIGH PLAINS.  AN ASSOCIATED LEE
   TROUGH WILL CORRESPONDINGLY STRENGTHEN FROM THE LOW SWD THROUGH THE
   CNTRL HIGH PLAINS.  ELSEWHERE...A QUASI-STATIONARY FRONT CURRENTLY
   FROM THE SRN PLAINS THROUGH LOWER OH VALLEY TO AN AREA OF LOW
   PRESSURE OVER THE MID ATLANTIC WILL BECOME MORE DIFFUSE WITH TIME.

   ...NRN/CNTRL PLAINS THIS AFTERNOON INTO TONIGHT...

   THE INFLUENCES OF THE LEAD SHORT-WAVE TROUGH MOVING THROUGH THE
   DAKOTAS TODAY...AND THE LARGER-SCALE CANADIAN UPPER-AIR SYSTEM WILL
   AUGMENT CIRCULATIONS ALONG THE SWD-MOVING COLD FRONT AND LEE TROUGH
   TO FOSTER CORRIDORS OF STORMS BY LATE AFTERNOON/EARLY EVENING OVER
   ND INTO NRN MT...AND FROM PARTS OF WRN/CNTRL SD INTO WRN NEB.  THE
   AMBIENT WARM SECTOR AIR MASS WILL BE CHARACTERIZED BY STEEP LAPSE
   RATES...MODEST BOUNDARY-LAYER MOISTURE CONTENT AND RESULTING MLCAPE
   OF 1500-2500 J/KG.  WHEN COUPLED WITH A VERTICALLY VEERING WIND
   PROFILE AND 30-35 KT OF DEEP-LAYER SHEAR THE SETUP WILL BE
   SUPPORTIVE OF SUPERCELLS CAPABLE OF LARGE HAIL...LOCALLY DAMAGING
   WINDS AND PERHAPS A TORNADO OR TWO.

   RECENT CONVECTION-ALLOWING MODEL GUIDANCE IS SUGGESTIVE THAT THE
   DIURNALLY ENHANCED STORMS OVER SD/NEB COULD EVOLVE INTO A SWD-MOVING
   MCS OVER SWRN NEB/NWRN KS LATER THIS EVENING OWING THE ENHANCEMENT
   OF MOIST/UNSTABLE INFLOW BY A NOCTURNALLY STRENGTHENING LLJ.  SHOULD
   THIS SCENARIO UNFOLD...THE RISK FOR ISOLATED DAMAGING WINDS COULD
   CONTINUE INTO TONIGHT OVER PARTS OF WRN KS.

   ...GULF COAST STATES THIS AFTERNOON INTO EVENING...

   FORCING FOR ASCENT/DCVA RELATED TO A VORTICITY MAXIMUM PROGRESSING
   SEWD INTO THE LOWER MS VALLEY COUPLED WITH LOW-LEVEL UPLIFT ALONG A
   COMPOSITE OUTFLOW BOUNDARY MOVING SEWD THROUGH NRN LA AND CNTRL
   PARTS OF MS AND AL WILL PROMOTE AN INCREASE IN STORM COVERAGE AND
   VIGOR ACROSS THE REGION THROUGH THE PEAK OF THE DIURNAL HEATING
   CYCLE.  WHILE VERTICAL SHEAR WILL WEAKEN WITH THE PROGRESSIVE SWD
   DISPLACEMENT OF THE WARM SECTOR TODAY...THE PRESENCE OF A VERY MOIST
   AIR MASS AND RESULTING MODERATE INSTABILITY WILL PROMOTE STRONG
   UP/DOWNDRAFTS WITH THE PRIMARY HAZARD BEING WET MICROBURSTS.

   ...ERN CAROLINAS THIS AFTERNOON...

   THE EWD PROGRESSION OF A SUBTLE MID-LEVEL IMPULSE THROUGH THE SRN
   APPALACHIANS HAS GIVEN RISE TO RECENT TSTM DEVELOPMENT OVER CNTRL
   NC.  DAYTIME HEATING OF A VERY MOIST AIR MASS OVER ERN NC WILL YIELD
   AN AXIS OF MODERATE INSTABILITY LATER TODAY WHICH WILL COINCIDE WITH
   A RESIDUAL BELT OF ENHANCED WLY FLOW IN THE 700-600-MB LAYER PER
   CURRENT VAD DATA AND FORECAST SOUNDINGS.  AS SUCH...THE POTENTIAL
   WILL EXIST FOR THE EVOLUTION OF BOWING STORM STRUCTURES CAPABLE OF
   DAMAGING WIND GUSTS INTO EARLY EVENING.

   ...GREAT BASIN THIS AFTERNOON...

   A SHORT-WAVE TROUGH OVER THE LOWER CO VALLEY WILL PROGRESS NNWWD
   THROUGH NV TODAY...PROMOTING A GRADUAL INCREASE IN TSTM COVERAGE AND
   INTENSITY.  MORNING VISIBLE SATELLITE SUGGESTS THAT STRONGER HEATING
   AND RESULTANT AIR MASS DESTABILIZATION WILL REMAIN CONFINED TO NRN
   NV WHERE A FEW BRIEFLY SEVERE STORMS MAY OCCUR LATER TODAY.

   ..MEAD/MOSIER.. 07/04/2015

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z