Aug 29, 2015 2000 UTC Day 1 Convective Outlook
Updated: Sat Aug 29 19:56:06 UTC 2015 (20150829 2000Z Day 1 shapefile | 20150829 2000Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20150829 2000 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 22,463 255,716 Bozeman, MT...Butte, MT...Helena, MT...Anaconda, MT...Belgrade, MT...
Probabilistic Tornado Graphic
20150829 2000 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
20150829 2000 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 % 22,463 255,716 Bozeman, MT...Butte, MT...Helena, MT...Anaconda, MT...Belgrade, MT...
Probabilistic Large Hail Graphic
20150829 2000 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
No Risk Areas Forecast
   SPC AC 291956

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0256 PM CDT SAT AUG 29 2015

   VALID 292000Z - 301200Z

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF SWRN AND INTO
   CENTRAL MT...

   ...SUMMARY...
   THUNDERSTORMS -- WITH ONE OR TWO OF THEM CAPABLE OF AN ISOLATED
   DAMAGING WIND GUST -- REMAIN POSSIBLE ACROSS SOUTHWESTERN/CENTRAL
   MONTANA THIS AFTERNOON. ADDITIONAL THUNDERSTORMS WILL BE POSSIBLE
   TODAY FROM THE SOUTHERN GREAT LAKES SOUTHWARD TO THE GULF COAST AND
   FLORIDA AND ACROSS THE SOUTHWESTERN DESERTS.

   ...DISCUSSION...
   ASIDE FROM MINOR ADJUSTMENTS TO THUNDER LINES...NO CHANGES ARE BEING
   MADE TO THE OUTLOOK ATTM AS CURRENT REASONING REMAINS VALID.

   ..GOSS.. 08/29/2015

   .PREV DISCUSSION... /ISSUED 1113 AM CDT SAT AUG 29 2015/

   ...SYNOPSIS...
   MORNING SATELLITE IMAGERY DEPICTS A DEEP UPPER TROUGH JUST OFF THE
   PACIFIC NW COAST WITH A LEAD SHORTWAVE TROUGH EMBEDDED WITHIN THIS
   TROUGH MOVING QUICKLY NEWD TOWARDS SW BRITISH COLUMBIA. CONTINUED
   EWD MOTION IS EXPECTED WITH THE UPPER TROUGH THROUGHOUT THE DAY WITH
   THE ENHANCED SWLY FLOW ALOFT AHEAD OF THE SYSTEM SPREADING INTO THE
   NRN ROCKIES AND THE NRN HIGH PLAINS. CONCURRENTLY...A DOWNSTREAM
   RIDGE -- EXTENDING ROUGHLY FROM THE SOUTHWEST NEWD INTO THE NRN
   PLAINS -- WILL BUILD...AMPLIFYING THE OVERALL UPPER PATTERN W OF THE
   MS RIVER. TUTT LOW JUST OFF THE SE LA COAST WILL DRIFT SLOWLY NEWD
   TOWARDS THE AL COAST/WRN FL PANHANDLE.

   RECENT SURFACE ANALYSIS PLACES A LOW OVER SE IA WITH A COLD FRONT
   EXTENDING FROM THIS LOW SWWD THROUGH CNTRL OK AND INTO SW TX. THIS
   FRONT IS EXPECTED TO BECOME INCREASINGLY DIFFUSE THROUGHOUT THE DAY.
   SOME TSTM ACTIVITY IS POSSIBLE ALONG THE FRONT THIS AFTERNOON ACROSS
   THE MID MS VALLEY BUT THE LACK OF BETTER SHEAR AND NEUTRAL TO
   POSSIBLY RISING HEIGHTS SHOULD KEEP ANY SEVERE RISK VERY LOW. HIGH
   PRESSURE...CURRENTLY CENTERED OVER SE VA...WILL PERSIST OVER MUCH OF
   THE ERN CONUS WHILE A COLD FRONT PUSHES EWD ACROSS THE NRN ROCKIES
   AND NRN HIGH PLAINS. 

   ...SW/CNTRL MT...
   DESPITE MEAGER LOW-LEVEL MOISTURE...ISOLATED TO WIDELY SCATTERED
   TSTMS ARE ANTICIPATED THIS AFTERNOON AS LARGE SCALE FORCING FOR
   ASCENT ASSOCIATED WITH THE APPROACHING UPPER TROUGH COMBINES WITH
   STEEP LOW-LEVEL LAPSE RATES AND MID-LEVEL MOISTURE TO FOSTER TSTM
   DEVELOPMENT. GIVEN THE STRENGTH OF THE MID/UPPER LEVEL WINDS /70 KT
   AT 500 MB/ AND PRESENCE OF STEEP LAPSE RATES...THERE IS AT LEAST
   SOME RISK FOR SOME STRONG WIND GUSTS AND A MARGINAL RISK/5 PERCENT
   WIND AREA HAS BEEN ADDED OVER THE REGION. 

   ...SOUTHEAST/FL...
   AT LEAST SCATTERED TSTM ACTIVITY IS EXPECTED ACROSS MUCH OF THE
   REGION THIS AFTERNOON WITH LOW POTENTIAL FOR A FEW DAMAGING WIND
   GUSTS. THE PRESENCE OF THE MID/UPPER LEVEL LOW MAY ENHANCE THE SHEAR
   A BIT ALONG THE W COAST OF FL BUT GENERALLY MOIST PROFILES SHOULD
   LIMIT LAPSE RATES AND INSTABILITY WITH THE EXPECTATION THAT SEVERE
   COVERAGE WILL REMAIN BELOW 5 PERCENT.

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z