Des Moines, IA...St. Joseph, MO...Rapid City, SD...Ames, IA...West Des Moines, IA...
Probabilistic Damaging Wind 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 %
79,799
3,000,116
Omaha, NE...Lincoln, NE...Des Moines, IA...St. Joseph, MO...Rapid City, SD...
5 %
348,027
20,609,373
Denver, CO...Kansas City, MO...Colorado Springs, CO...Tampa, FL...Aurora, CO...
Probabilistic Large Hail 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.
Omaha, NE...Lincoln, NE...Des Moines, IA...St. Joseph, MO...Rapid City, SD...
5 %
251,861
5,805,990
Kansas City, MO...Colorado Springs, CO...Aurora, CO...Kansas City, KS...Topeka, KS...
SPC AC 080559
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT SAT AUG 08 2015
VALID 081200Z - 091200Z
...THERE IS A SLGT RISK OF SVR TSTMS LOWER MO VALLEY...
...THERE IS A SLGT RISK OF SVR TSTMS BLACK HILLS AREA...
...THERE IS A SLGT RISK OF SVR TSTMS CNTRL HIGH PLAINS...
...THERE IS A MRGL RISK OF SVR TSTMS N-CNTRL STATES...
...THERE IS A MRGL RISK OF SVR TSTMS ERN GULF COAST STATES...
...SUMMARY...
SEVERE STORMS APPEAR MOST LIKELY OVER PARTS OF THE LOWER MISSOURI
VALLEY DURING THE LATE AFTERNOON AND EVENING. TORNADOES...VERY LARGE
HAIL...AND DAMAGING WINDS WILL BE POSSIBLE. LARGE HAIL AND SEVERE
WINDS SHOULD ACCOMPANY A FEW STORM CLUSTERS OVER THE NORTHERN AND
CENTRAL HIGH PLAINS IN THE LATE AFTERNOON AND EVENING.
...LOWER MO VALLEY AREA...
PRIMARY FORECAST CONCERN IS OVER THE POTENTIAL FOR A SIGNIFICANT
TORNADO SETUP ACROSS A LOCALIZED PORTION OF SERN NEB TO SWRN IA
WHERE A 10 SIG TOR PROBABILITY WAS CONSIDERED FOR THIS OUTLOOK. BUT
WITH PREDICTABILITY RESIDING PREDOMINATELY ON THE MESO-BETA
SCALE...WILL DEFER TO LATER OUTLOOKS FOR POSSIBLE DELINEATION OF AN
ENHANCED RISK PROBABILITY.
ONGOING MCS CENTERED OVER S-CNTRL NEB/N-CNTRL KS SHOULD BE IN A
DECAYING STATE AT 12Z THIS MORNING. REMNANT MCV IS PROGGED TO SHIFT
E THIS MORNING OVER IA AND THEN DAMPEN OVER THE MIDWEST. GUIDANCE IS
HIGHLY CONSISTENT WITH A LACK OF DIURNALLY DRIVEN CONVECTIVE
DEVELOPMENT ASSOCIATED WITH THE REMNANT MCV PERHAPS DUE TO THE
FEATURE OUTPACING THE BUOYANT MOIST SECTOR CURRENTLY ALONG THE MS
RIVER WWD. THE MORE PROBABLE SCENARIO IS FOR RENEWED TSTM
DEVELOPMENT LATE AFTERNOON OR EVENING ACROSS PARTS OF THE LOWER MO
VALLEY WHERE PRONOUNCED DIFFERENTIAL HEATING IS EXPECTED ON THE SRN
EDGE OF RESIDUAL CLOUD COVERAGE/OUTFLOW BOUNDARY FROM THE DECAYING
MCS. A RATHER MOISTURE-RICH BOUNDARY LAYER BENEATH A PLUME OF
MODERATELY STEEP MID-LEVEL LAPSE RATES WILL RESULT IN A CORRIDOR OF
STRONG DESTABILIZATION WITH MLCAPE AOA 2500 J/KG.
UNCERTAINTY DOES EXIST OVER THE TIMING OF TSTM INITIATION GIVEN
CAPPING CONCERNS WITH LARGELY 700-MB SWLYS MAINTAINING WAA. SOME
CAMS SUGGEST TSTMS WILL BE DELAYED UNTIL JUST AFTER SUNSET AS THE
LLJ INTENSIFIES AND PROVIDES NECESSARY FORCED ASCENT. OTHER GUIDANCE
INDICATES LATE AFTERNOON INITIATION PERHAPS AIDED BY A SUBTLE
MID-LEVEL IMPULSE EJECTING FROM THE FOUR CORNERS AREA. SHOULD THIS
OCCUR...RELATIVELY STRONG LOW-LEVEL SRH ALONG THE EARLY-DAY OUTFLOW
BOUNDARY/RESULTANT EFFECTIVE FRONT COULD FAVOR A COUPLE INTENSE
SUPERCELLS /PARTICULARLY GIVEN THAT OVERALL FORCING SHOULD BE
MODEST/. A CONDITIONAL RISK FOR VERY LARGE HAIL AND A STRONG TORNADO
IS APPARENT. WILL MAINTAIN INHERITED SIGNIFICANT SEVERE
PROBABILITIES /DRIVEN BY HAIL/...BUT MESOSCALE PREDICTABILITY IS TOO
LOW FOR A LOCALIZED UPGRADE TO ENHANCED RISK PROBABILITIES THIS
OUTLOOK. REGARDLESS OF WHEN TSTM INITIATION OCCURS...UPSCALE GROWTH
INTO A LATE EVENING MCS SEEMS PROBABLE WITH A DAMAGING WIND RISK
MOST LIKELY DURING THE EARLY STAGES OF STORM-SCALE MERGERS UNTIL
CONVECTION TENDS TO WEAKEN OVERNIGHT.
...BLACK HILLS AREA...
LOW-AMPLITUDE SHORTWAVE TROUGH OVER THE ERN GREAT BASIN SHOULD REACH
THE NRN HIGH PLAINS BY EARLY SUN. WITH A LEE CYCLONE BECOMING
ESTABLISHED OVER ERN WY...A MODEST INCREASE IN LOW-LEVEL MOISTURE IS
EXPECTED FROM THE LOWER PLAINS. OVERALL BUOYANCY WILL BE
LIMITED...BUT STEEP LAPSE RATES AND ELONGATED STRAIGHT-LINE
HODOGRAPHS SHOULD FAVOR A COUPLE SPLITTING SUPERCELLS AND/OR AN
ORGANIZED CLUSTER WITH LARGE HAIL/SEVERE WINDS AS THE PRIMARY
HAZARDS.
...CNTRL HIGH PLAINS...
WHILE FORCING FOR ASCENT AND VERTICAL SHEAR SHOULD NOT BE AS STRONG
AS FARTHER N...COMPARATIVELY RICHER LOW-LEVEL MOISTURE SHOULD STILL
FAVOR ISOLATED TO WIDELY SCATTERED TSTMS FORMING ALONG A LEE TROUGH.
A COUPLE OF SEMI-ORGANIZED CLUSTERS WITH A SEVERE WIND/HAIL THREAT
SHOULD DEVELOP WITH THE MOST PROBABLE CORRIDOR ACROSS PARTS OF
E-CNTRL CO/W-CNTRL KS TO THE NW OF A BAROCLINIC ZONE PROGGED FROM
CNTRL KS TO THE OK/TX PANHANDLES.
..GRAMS/MOSIER.. 08/08/2015
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