Sep 15, 2015 1300 UTC Day 1 Convective Outlook
Updated: Tue Sep 15 12:41:06 UTC 2015 (20150915 1300Z Day 1 shapefile | 20150915 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20150915 1300 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 114,726 733,936 Bismarck, ND...Minot, ND...Kearney, NE...Garden City, KS...North Platte, NE...
Probabilistic Tornado Graphic
20150915 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.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20150915 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.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 114,855 731,744 Bismarck, ND...Minot, ND...Kearney, NE...Garden City, KS...North Platte, NE...
Probabilistic Large Hail Graphic
20150915 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.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 65,315 457,194 Bismarck, ND...Minot, ND...Garden City, KS...Mandan, ND...Lamar, CO...
   SPC AC 151241

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0741 AM CDT TUE SEP 15 2015

   VALID 151300Z - 161200Z

   ...THERE IS A MRGL RISK OF SVR TSTMS OVER PARTS OF THE CNTRL HIGH
   PLNS...

   ...THERE IS A MRGL RISK OF SVR TSTMS OVER PARTS OF THE NRN PLNS...

   ...SUMMARY...
   ISOLATED STRONG STORMS ARE POSSIBLE MAINLY ACROSS PARTS OF THE
   CENTRAL AND NORTHERN PLAINS LATE THIS AFTERNOON AND EVENING.

   ...SYNOPTIC SETUP...
   LARGE-SCALE TROUGH WILL CONTINUE TO AMPLIFY ALONG THE W CST THIS
   PERIOD AS LEAD IMPULSE NOW OVER ERN WA/ORE SHEARS NE INTO
   AB/SK...AND UPSTREAM SPEED MAX DIGS SE TO NEAR THE ORE CST BY 12Z
   WED. AS THIS OCCURS...RESIDUAL SRN STREAM JET NOW OVER THE ERN GRT
   BASIN/CNTRL RCKYS SHOULD BECOME INCREASINGLY ABSORBED WITHIN
   BROADENING CYCLONIC FLOW OVER THE WEST. 

   AT LWR LVLS...ERN MT SFC LOW SHOULD MOVE E INTO W CNTRL ND BY THIS
   EVE BEFORE ACCELERATING NE INTO WRN ONT TNGT/EARLY WED. TRAILING
   COLD FRONT WILL ADVANCE E/SE ACROSS THE NRN HIGH PLNS LATER
   TODAY...OVERTAKING PRE-FRONTAL LEE TROUGH EXTENDING SSW INTO ERN CO.
   PERSISTENT SSW FLOW E OF THE TROUGH WILL DRAW GULF MOISTURE NWD
   ACROSS E TX TODAY...AND INTO THE SRN OZARKS TNGT. BUT MOISTURE
   RETURN WILL BE MORE LIMITED FARTHER N AND W...PERHAPS SOMEWHAT
   AUGMENTED BY EVAPOTRANSPIRATION OVER THE NRN PLNS/UPR MS VLY.  

   ...CNTRL PLNS AFTN/EVE...
   LEE TROUGH SHOULD BE THE FOCUS FOR WDLY SCTD...HIGH-BASED...
   LATE-DAY TSTMS OVER THE CNTRL HIGH PLNS...WHERE A VERY
   WARM/WELL-MIXED ENVIRONMENT WILL EXIST BENEATH AXIS OF 30+ KT SWLY
   MID-LVL FLOW ASSOCIATED WITH RESIDUAL SRN STREAM JET. COUPLED WITH
   MODEST FORCING FOR ASCENT...SETUP MAY YIELD A FEW INSTANCES OF
   LOCALLY DMGG WIND AND PERHAPS A SPOT OR TWO OF MARGINALLY SVR HAIL
   EWD INTO WRN/NRN KS AND CNTRL NEB BY EARLY TNGT.

   ...ND LATE AFTN INTO TNGT...
   ALTHOUGH COVERAGE OF STORMS MAY REMAIN LIMITED...COMBINATION OF
   FRONTAL CONVERGENCE AND GLANCING INFLUENCE OF PASSING AB/SK UPR
   IMPULSE SHOULD BE SUFFICIENT TO BREAK EML CAP AND FOSTER DEVELOPMENT
   OF ISOLD TO WDLY SCTD STORMS ALONG AND BEHIND MERGING COLD FRONT/LEE
   TROUGH IN ND AND PERHAPS SE MT/NE WY/NW SD LATE TODAY INTO TNGT.
   ASSUMING STORMS DO FORM...ISOLD SVR WIND AND/OR HAIL COULD OCCUR
   GIVEN STEEP LOW TO MID-LVL LAPSE RATES...PRESENCE OF ADEQUATE
   MOISTURE /PW AOA 1 INCH/...AND 30+ KT SWLY DEEP SHEAR.

   ...GRT BASIN AFTN/EVE...
   DIURNALLY ENHANCED STORMS ONCE AGAIN EXPECTED OVER MUCH OF THE GRT
   BASIN...WITH THE GREATEST CONCENTRATION EXPECTED FROM MUCH OF UT AND
   ERN ID INTO WRN WY/CO...ALONG BAND OF SLIGHTLY STRONGER FLOW/ASCENT
   WITH RESIDUAL SRN STREAM JET. A FEW STORMS ALSO MAY OCCUR IN NV.
   MODERATE CYCLONIC UPR FLOW COULD YIELD A FEW STRONG GUSTS THIS AFTN
   AND EVE. BUT MODEST HEATING/BUOYANCY SHOULD KEEP OVERALL SVR THREAT
   LOW/ISOLD.

   ..CORFIDI/COOK.. 09/15/2015

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z