Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 231950
SWODY1
SPC AC 231948

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0248 PM CDT TUE SEP 23 2014

VALID 232000Z - 241200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
A FEW THUNDERSTORMS ACROSS THE CENTRAL PLAINS COULD BE STRONG TO
MARGINALLY SEVERE THIS AFTERNOON THROUGH EARLY EVENING.

...CNTRL HIGH PLAINS...

FORECAST APPEARS ON TRACK WITH STORMS EXPECTED TO DEVELOP OVER THE
CNTRL HIGH PLAINS FROM WRN/SWRN KS INTO CNTRL NEB ALONG AND EAST OF
A LEE TROUGH WHERE ABUNDANT HEATING IS DESTABILIZING THE BOUNDARY
LAYER WITH MLCAPE FROM 1000-1500 J/KG. BELT OF STRONGER WINDS ALOFT
ALONG SRN PERIPHERY OF AN UPPER TROUGH IS CONTRIBUTING TO 30-35 KT
VERTICAL SHEAR...SO A FEW STORMS COULD DEVELOP WEAK MID-LEVEL
UPDRAFT ROTATION. STORMS COULD BE A LITTLE MORE CONCENTRATED OVER
NCNTRL NEB AHEAD OF A PROGRESSIVE VORT MAX AS WELL AS OVER A PORTION
OF WRN/SWRN KS WHERE THERMAL AXIS INTERCEPTS WRN PERIPHERY OF PLUME
OF GREATER LOW-MID LEVEL MOISTURE. ISOLATED STRONG WIND GUSTS AND
SOME HAIL WILL BE POSSIBLE THROUGH EARLY EVENING BEFORE STORMS BEGIN
TO DIMINISH WITH LOSS OF DIABATIC WARMING.

..DIAL.. 09/23/2014

.PREV DISCUSSION... /ISSUED 1121 AM CDT TUE SEP 23 2014/

...SYNOPSIS...

MID-LEVEL RIDGE AMPLIFICATION WILL OCCUR ACROSS THE INTERIOR WEST IN
RESPONSE TO THE EWD PROGRESSION OF AN INTENSE TROUGH OVER THE NERN
PACIFIC...AND THE TRANSLATION OF A SHORTER-WAVELENGTH TROUGH FROM
THE NRN AND CNTRL PLAINS INTO THE UPPER MS VALLEY. ELSEWHERE...A MID
TO UPPER-LEVEL LOW WILL REMAIN QUASI-STATIONARY OVER THE CAROLINAS.

AT THE SURFACE...MID-MORNING MESOANALYSIS PLACED A CYCLONE OVER SWRN
SD WITH AN ASSOCIATED LEE TROUGH EXTENDING SSWWD TO A WEAKER LOW
OVER E-CNTRL CO BEFORE BECOMING MORE DIFFUSE OVER THE OK/TX PNHDLS.
AN OUTFLOW BOUNDARY REMNANT FROM OVERNIGHT STORMS STRETCHED FROM
CNTRL KS WWD TO THE ERN CO LOW. THE LEE TROUGH SHOULD CONTINUE
SLOWLY EWD TODAY WITH THE PRIMARY AREA OF LOW PRESSURE BECOMING
ESTABLISHED OVER WRN NEB. THE ABOVE-MENTIONED OUTFLOW BOUNDARY
SHOULD EVENTUALLY WASH OUT THIS AFTERNOON.

...CNTRL PLAINS THIS AFTERNOON/EVENING...

DECREASING CLOUDS IN THE WAKE OF OVERNIGHT NIGHT TSTMS COUPLED WITH
A RELATIVELY MOIST WARM SECTOR WILL CONTRIBUTE TO A DESTABILIZING
AIR MASS TODAY AHEAD OF THE LEE TROUGH WITH AFTERNOON MLCAPE
APPROACHING 1000-1500 J/KG. WHILE THE PRIMARY CORRIDOR OF HEIGHT
FALLS/DCVA ASSOCIATED WITH THE NRN/CNTRL PLAINS TROUGH WILL SHIFT
INTO THE UPPER MS VALLEY...MORNING WATER VAPOR IMAGERY AND MODEL
GUIDANCE SUGGEST THAT A WEAK VORTICITY LOBE OVER WY MAY PROGRESS
SEWD INTO THE CNTRL HIGH PLAINS...POTENTIALLY ENHANCING DEEP-LAYER
ASCENT ALONG THE LEE TROUGH. THIS SHOULD PROMOTE ISOLATED TO WIDELY
SCATTERED STORM DEVELOPMENT BY MID TO LATE AFTERNOON FROM N-CNTRL
NEB INTO WRN KS.

A SUBSET OF THESE STORMS COULD EXHIBIT SOME MID-LEVEL UPDRAFT
ROTATION OWING TO THE OVERLAP OF MODERATE INSTABILITY AND A
VERTICALLY VEERING WIND PROFILE WITH AROUND 30 KT OF DEEP-LAYER
SHEAR. AS SUCH...ISOLATED OCCURRENCES OF MARGINALLY SEVERE HAIL
AND/OR LOCALLY STRONG WIND GUSTS WILL BE POSSIBLE INTO THIS EVENING
PRIOR TO THE STABILIZATION OF THE BOUNDARY LAYER.




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