Sep 29, 2014 1730 UTC Day 2 Convective Outlook
Updated: Mon Sep 29 17:26:53 UTC 2014 (20140929 1730Z Day 2 shapefile | 20140929 1730Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20140929 1730 UTC Day 2 Outlook Graphic
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 34,547 1,331,196 Lincoln, NE...Sioux Falls, SD...Sioux City, IA...Fremont, NE...Norfolk, NE...
Probabilistic Graphic
20140929 1730 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 34,547 1,331,196 Lincoln, NE...Sioux Falls, SD...Sioux City, IA...Fremont, NE...Norfolk, NE...
5 % 133,576 2,964,279 Omaha, NE...Wichita, KS...Council Bluffs, IA...Bellevue, NE...Salina, KS...
   SPC AC 291726

   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1226 PM CDT MON SEP 29 2014

   VALID 301200Z - 011200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN SD/NEB AND
   NWRN IA...

   ...SUMMARY...
   ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE TUESDAY ACROSS PARTS OF
   THE EASTERN PLAINS FROM SOUTH DAKOTA INTO NEBRASKA.  A FEW STRONG
   STORMS MAY ALSO DEVELOP SOUTH INTO THE HIGH PLAINS OF THE EASTERN
   TEXAS PANHANDLE.  THE POSSIBILITY FOR A TORNADO OR TWO APPEARS
   HIGHEST ACROSS EASTERN SOUTH DAKOTA INTO EASTERN NEBRASKA DURING THE
   AFTERNOON...OTHERWISE STRONG WINDS ARE THE PRIMARY THREAT.

   ...SYNOPSIS...
   A POTENT SHORTWAVE TROUGH --EMBEDDED WITHIN A LARGER SCALE MID-LEVEL
   TROUGH-- WILL MOVE NNEWD FROM WRN NEB/WRN SD TUESDAY MORNING TO THE
   SD/ND BORDER BY EVENING.  A TRAILING UPSTREAM PV FILAMENT WITHIN
   CYCLONIC FLOW WILL QUICKLY MOVE FROM THE CNTRL HIGH PLAINS TO THE
   MID MO RIVER VALLEY BY MID-AFTERNOON.  A SURFACE LOW UNDERGOING
   DEEPENING PRIOR TO TUESDAY MORNING WILL MOVE NEWD FROM WRN SD INTO
   SRN MANITOBA DURING THE PERIOD.  A FRONT OVER THE MID MS RIVER
   VALLEY WILL ADVANCE SLOWLY NWD AS A WARM FRONT OVER THE MID MO RIVER
   VALLEY AND A LEE TROUGH/DRYLINE WILL EXTEND SWD ACROSS NEB INTO THE
   SRN HIGH PLAINS.  MEANWHILE FARTHER E...A BLOCKING PATTERN FEATURING
   A DIGGING IMPULSE OVER THE MID-ATLANTIC STATES WILL AID IN
   MAINTAINING A SURFACE RIDGE FROM ONTARIO INTO THE WRN GREAT LAKES.  

   ...MID MO RIVER VALLEY...
   A LOW-LEVEL MOIST FEED FROM THE S AND STRONG WARM ADVECTION ONGOING
   EARLY TUESDAY MORNING WILL PROBABLY LEAD TO SCTD SHOWERS/STORMS OVER
   PARTS OF THIS REGION.  WHILE A SMALL HAIL THREAT MAY EXIST WITH THE
   STRONGER EARLY-DAY STORMS ALONG THE WARM FRONT...ADDITIONAL STORM
   DEVELOPMENT IS LIKELY LATER IN THE DAY WHEN THE THREAT FOR STRONG TO
   SEVERE STORMS WILL BE GREATEST.  STRONG UVV/S ATTENDANT TO THE
   MID-LEVEL VORTICITY MAXIMUM MAY INITIATE STORMS BY EARLY AFTERNOON
   OVER PARTS OF SD WITHIN AN INCREASINGLY NARROW MOIST/INSTABILITY
   CORRIDOR WITH N-NWWD EXTENT TOWARDS THE SURFACE LOW.  MODELS SHOW
   SURFACE DEWPOINTS IN THE 50S TO LOWER 60S RESULTING IN SBCAPE
   RANGING FROM AROUND 2000 J/KG OVER ERN NEB TO 500 J/KG OVER CNTRL
   SD.  STRONG EFFECTIVE SHEAR WILL SUPPORT ORGANIZED STORMS CAPABLE OF
   ISOLD DMGG WINDS/LARGE HAIL...INCLUDING THE THREAT FOR SUPERCELLS
   WITH ANY QUASI-DISCRETE ROBUST UPDRAFT.  RELATIVELY-BACKED SSELY
   FLOW INVOF THE WARM FRONTAL ZONE WILL RESULT IN ENLARGED HODOGRAPHS.
   A TORNADO RISK MAY DEVELOP DURING A SEVERAL HOUR WINDOW IF SUPERCELL
   STORMS CAN MOVE INTO/INTERACT FAVORABLY IN A NARROW ZONE ON THE WEST
   EDGE OF VORTICITY-RICH LOW-LEVEL FLOW AND STEEPER LOW-LEVEL LAPSE
   RATES FROM THE W AND SW.  THE LOSS OF DAYTIME HEATING AND DECREASING
   INSTABILITY FARTHER N/E SHOULD LEAD TO STORMS WEAKENING DURING THE
   EVENING INTO THE OVERNIGHT HOURS AND A LESSENING SEVERE RISK.  

   ...KS INTO WRN OK/TX PANHANDLE...
   BOUNDARY LAYER DEWPOINTS IN THE UPPER 50S TO AROUND 60 AND STRONG
   HEATING WILL PROBABLY RESULT IN MODERATE BUOYANCY /1000-1500 J PER
   KG MLCAPE/ DEVELOPING BY MID-LATE AFTERNOON.  WEAK LOW-LEVEL
   CONFLUENCE AND A GRADUAL WEAKENING OF THE CAP WILL LIKELY RESULT IN
   SEVERAL WIDELY-SPACED ISOLD CLUSTERS OF STORMS BY LATE AFTERNOON
   INTO THE EARLY EVENING.  STRONG DEEP-LAYER SHEAR ORIENTED
   PERPENDICULAR TO THE LEE TROUGH WOULD FAVOR A DISCRETE MODE AND
   RESULT IN A MIX OF MULTICELL/SUPERCELL ACTIVITY POTENTIALLY CAPABLE
   OF AN ISOLD LARGE HAIL/STRONG WIND GUST THREAT.  A CONTINUATION OF
   SOME STORM ACTIVITY COULD MOVE EWD AND LINGER INTO THE OVERNIGHT
   HOURS ON THE NOSE OF A 40 KT LLJ OVER ERN KS.

   ..SMITH.. 09/29/2014

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z