Severe Storm Outlook Narrative (AC)
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
000
ACUS02 KWNS 301713
SWODY2
SPC AC 301712

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1212 PM CDT TUE SEP 30 2014

VALID 011200Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CNTRL
PLAINS...MID MO VALLEY AND SRN PLAINS...

...SUMMARY...
SCATTERED SEVERE THUNDERSTORMS ARE EXPECTED ACROSS PARTS OF THE
CENTRAL PLAINS AND MID MISSOURI VALLEY WEDNESDAY WITH A HIGHER
CONCENTRATION OF SEVERE STORMS POSSIBLE IN PARTS OF EASTERN KANSAS
AND FAR SOUTHEAST NEBRASKA.  LARGE HAIL AND DAMAGING WINDS SHOULD
OCCUR WITH THE STRONGER THUNDERSTORMS.  A TORNADO OR TWO WILL BE
POSSIBLE.

...CNTRL PLAINS/MID MO VALLEY...
A LEAD SHORTWAVE TROUGH WILL MOVE ACROSS THE CNTRL PLAINS AND MID MO
VALLEY ON WEDNESDAY AS A LARGE-SCALE UPPER-LEVEL TROUGH MOVES
THROUGH THE FOUR CORNERS REGION. AT THE SFC...A LOW WILL DEEPEN IN
THE CNTRL PLAINS AS A COLD FRONT ADVANCES SEWD ACROSS THE CNTRL HIGH
PLAINS. A 30 TO 40 KT LOW-LEVEL JET SHOULD BE ONGOING ACROSS ERN KS
AND SE NEB AT DAYBREAK WEDNESDAY WITH A CLUSTER OF ELEVATED
THUNDERSTORMS LOCATED NEAR THE NOSE OF THE JET IN SE NEB AND NE KS.
MODEL CONSENSUS WEAKENS THIS CLUSTER OF STORMS BY EARLY AFTERNOON AS
MODERATE INSTABILITY DEVELOPS FROM NRN OK NWD INTO ERN NEB. THE
DEEPENING SFC LOW SHOULD HELP LOW-LEVEL CONVERGENCE TO BECOME
ENHANCED BY MID TO LATE AFTERNOON WITH SFC-BASED THUNDERSTORM
DEVELOPMENT POSSIBLE TO THE NORTH AND EAST OF THE LOW. MODEL
CONSENSUS AGREES WITH THIS SCENARIO WITH A GRADUAL INCREASE IN STORM
COVERAGE DURING THE EARLY TO MID EVENING.

FORECAST SOUNDINGS FOR TOPEKA AND EMPORIA KS AT 00Z/THURSDAY SHOW
IMPRESSIVE SHEAR PROFILES WITH 0-6 KM SHEAR OF 55 TO 60 KT.
SUBSTANTIAL VEERING WITH HEIGHT IS FORECAST FROM THE SFC TO ABOUT
800 MB. THIS SHEAR ENVIRONMENT SHOULD SUPPORT SUPERCELL DEVELOPMENT
DURING THE LATE AFTERNOON AND EARLY EVENING. IN ADDITION...0-3 KM
STORM RELATIVE HELICITIES OF 350 TO 400 M2/S2 MAY BE FAVORABLE FOR A
FEW TORNADOES AND A STRONG TORNADO CAN NOT BE RULED OUT. A WIND
DAMAGE THREAT SHOULD ALSO EXIST WITH SUPERCELLS BUT MAY ALSO DEVELOP
DURING THE EVENING WITH ANY SHORT-LINE SEGMENTS THAT CAN ORGANIZE.
HAVE ADDED A 30 PERCENT PROBABILITY FOR SEVERE IN PARTS OF ERN KS
AND FAR SE NEB WHERE THE STRONGEST COMBINATION OF INSTABILITY AND
SHEAR IS FORECAST AND WHERE CONVECTIVE COVERAGE IS FORECAST TO BE
THE GREATEST. OTHER SEVERE STORMS WITH LARGE HAIL...WIND DAMAGE AND
PERHAPS A TORNADO MAY DEVELOP NWD INTO ECNTRL NEB AND SW IA.

...SRN PLAINS...
AN UPPER-LEVEL TROUGH WILL MOVE ACROSS THE FOUR CORNERS REGION
WEDNESDAY AS A 45 TO 55 KT MID-LEVEL JET MOVES ENEWD THROUGH THE
BASE OF THE TROUGH AND INTO THE SRN HIGH PLAINS. AT THE SFC...WINDS
WILL BE SLY ACROSS MUCH OF THE SRN PLAINS AS A LOW DEEPENS ACROSS
SRN KS. SFC DEWPOINTS IN THE MID TO UPPER 60S SHOULD ENABLE MODERATE
INSTABILITY TO BE IN PLACE BY AFTERNOON AS A DRYLINE SETS UP ACROSS
PARTS OF WRN OK AND NW TX. ISOLATED THUNDERSTORM DEVELOPMENT IS
EXPECTED ALONG THE DRYLINE DURING THE LATE AFTERNOON AS LOW-LEVEL
CONVERGENCE BECOMES ENHANCED. FORECAST SOUNDINGS FOR GAGE OK AND
CLINTON OK AT 00Z/THURSDAY SHOW 0-6 KM SHEAR OF 35 KT WITH MLCAPE
NEAR 1500 J/KG. THIS COMBINED WITH STEEP LOW-LEVEL LAPSE RATES MAY
BE ENOUGH FOR A MARGINAL WIND DAMAGE THREAT. A THREAT FOR HAIL MAY
ALSO DEVELOP WITH STORMS THAT CAN INITIATE IN AREAS THAT DESTABILIZE
THE MOST.

..BROYLES.. 09/30/2014



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.