Aug 26, 2014 1630 UTC Day 1 Convective Outlook
Updated: Tue Aug 26 16:28:00 UTC 2014 (20140826 1630Z Day 1 shapefile | 20140826 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20140826 1630 UTC Day 1 Outlook Graphic
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Tornado Graphic
20140826 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.
Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20140826 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.
Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 218,195 20,001,814 Chicago, IL...Indianapolis, IN...St. Louis, MO...Lincoln, NE...Fort Wayne, IN...
Probabilistic Large Hail Graphic
20140826 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.
Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 175,747 3,126,772 Omaha, NE...Lincoln, NE...St. Joseph, MO...St. George, UT...Council Bluffs, IA...
   SPC AC 261628

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1128 AM CDT TUE AUG 26 2014

   VALID 261630Z - 271200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SUMMARY...
   ISOLATED SEVERE STORMS WITH HAIL AND WIND ARE POSSIBLE FROM THE
   CENTRAL HIGH PLAINS TO OHIO VALLEY. ISOLATED SEVERE STORMS ALSO MAY
   OCCUR OVER NORTHERN ARIZONA AND SOUTHERN UTAH.

   ...SYNOPSIS...

   A PROGRESSIVE POLAR-BRANCH OF WESTERLIES WILL REMAIN LARGELY
   CONFINED TO CANADA...WHILE OVER THE CONUS...A DEEP-LAYER CYCLONE
   WILL EDGE ESEWD THROUGH THE GREAT BASIN WITH A FLATTENED DOWNSTREAM
   RIDGE CENTERED OVER THE TN VALLEY. AT THE SURFACE...A COLD FRONT
   WILL SETTLE SEWD THROUGH THE REMAINDER OF THE GREAT LAKES INTO THE
   OH VALLEY WITH THE WRN EXTENSION OF THIS FRONT SLOWLY SHIFTING NWD
   IN RESPONSE TO LEE CYCLOGENESIS OVER THE CNTRL HIGH PLAINS. 

   ...UPPER GREAT LAKES/OH VALLEY THIS AFTERNOON/EVENING...

   A NNE-SSW-ORIENTED BAND OF TSTMS MOVING THROUGH THE CHICAGOLAND AREA
   AS OF 16Z HAS EXHIBITED SOME FORWARD-PROPAGATING CHARACTERISTICS
   WITH ISOLATED WIND DAMAGE REPORTED ALONG ITS TRACK. BY AFTERNOON...A
   SUBSET OF THESE STORMS WILL LIKELY MERGE WITH A DOWNSHEAR CLUSTER OF
   SLOWER-MOVING TSTMS ONGOING OVER IND. 

   DAYTIME HEATING COUPLED WITH THE PRESENCE OF A VERY MOIST BOUNDARY
   LAYER WILL ONCE AGAIN YIELD A STRONGLY UNSTABLE AIR MASS AHEAD OF
   THESE STORM CLUSTERS WITH MLCAPE APPROACHING 3500-4500 J/KG. AND
   SIMILAR TO MONDAY...EXPECT STORM MOTIONS TO BECOME MORE SLY WITH
   TIME AS ACTIVITY IS DRAWN INTO THE BACKSIDE OF A MID-LEVEL
   ANTICYCLONE CENTERED OVER THE OZARKS. VERTICAL SHEAR WILL ONCE AGAIN
   REMAIN WEAK...BUT THE PRESENCE OF THE STRONG INSTABILITY AND HIGH
   MOISTURE CONTENT WILL FOSTER INTENSE WATER-LOADED DOWNDRAFTS CAPABLE
   OF DAMAGING SURFACE WINDS.

   AN UPGRADE TO SLIGHT RISK REMAINS POSSIBLE AT 20Z SHOULD IT BECOME
   MORE APPARENT THAT AN ORGANIZED COLD POOL AND ASSOCIATED GREATER
   SEVERE THREAT WILL MATERIALIZE.

   ...CNTRL HIGH PLAINS INTO MID MO VALLEY THIS AFTERNOON INTO
   TONIGHT...

   LOW-LEVEL UPSLOPE FLOW COUPLED WITH THE APPROACH OF A WEAK MID-LEVEL
   PERTURBATION FROM THE SRN ROCKIES WILL PROMOTE SCATTERED TSTM
   DEVELOPMENT OVER THE CNTRL HIGH PLAINS LATER TODAY. WHILE EARLY-DAY
   CLOUDS ARE EXPECTED TO SLOW THE DESTABILIZATION PROCESS...CORRIDORS
   OF MODERATE INSTABILITY /I.E. MLCAPE OF 1000-1500 J PER KG/ MAY
   DEVELOP BY AFTERNOON...SUPPORTING THE DEVELOPMENT OF A FEW INTENSE
   STORMS. DEEP-LAYER SHEAR IS EXPECTED TO BE WEAKER THAN THAT OBSERVED
   ON MONDAY...WHICH SHOULD LIMIT THE POTENTIAL FOR AN ORGANIZED SEVERE
   WEATHER EVENT. NONETHELESS...ISOLATED OCCURRENCES OF MARGINALLY
   SEVERE HAIL AND/OR LOCALLY DAMAGING WIND GUSTS ARE POSSIBLE.

   SIMILAR TO LAST NIGHT...ELEVATED TSTMS ARE ONCE AGAIN EXPECTED TO
   DEVELOP OVERNIGHT OVER NEB INTO IA AS WAA IS ENHANCED TO THE NORTH
   OF THE SURFACE FRONT BY A NOCTURNALLY STRENGTHENING LLJ. THE
   STRONGEST STORMS MAY BE CAPABLE OF GUSTY WINDS AND SOME HAIL.

   ...LOWER CO VALLEY/SRN GREAT BASIN THIS AFTERNOON/EVENING...

   INCREASING HEIGHT FALLS/DCVA AHEAD OF THE MID TO UPPER-LEVEL LOW
   WILL INTERACT WITH A STEEP LAPSE RATE AND AT LEAST MODESTLY SHEARED
   ENVIRONMENT TO YIELD ISOLATED STRONG TO SEVERE STORMS LATER TODAY.
   LOCALLY STRONG WIND GUSTS AND/OR MARGINALLY SEVERE HAIL MAY
   ACCOMPANY THE STRONGEST STORMS.

   ..MEAD/COHEN.. 08/26/2014

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