Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 271948
SWODY1
SPC AC 271947

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0247 PM CDT WED AUG 27 2014

VALID 272000Z - 281200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE CENTRAL
HIGH PLAINS...

...SUMMARY...
WIDELY SCATTERED SEVERE STORMS CAPABLE OF HAIL...DAMAGING
STRAIGHT-LINE WINDS AND PERHAPS A COUPLE OF TORNADOES ARE EXPECTED
THROUGH THE EVENING ACROSS PARTS OF EASTERN COLORADO INTO NORTHWEST
KANSAS AND SOUTHWEST NEBRASKA.

...CENTRAL HIGH PLAINS...

ISOLATED TO WIDELY SCATTERED SEVERE THUNDERSTORMS ARE STILL EXPECTED
INTO THE EVENING/OVERNIGHT HOURS. A FEW STRONG STORMS WERE
DEVELOPING LATE THIS AFTERNOON ACROSS PARTS OF WESTERN KS AND A
GRADUAL INCREASE IN ACTIVITY SHOULD CONTINUE THE NEXT SEVERAL HOURS.
REF MCD 1627 FOR MORE DETAILS.

...NORTHEAST STATES...

ONLY MINOR ADJUSTMENTS WERE MADE TO THE GENERAL THUNDERSTORM LINE
AND THE 5 PERCENT WIND AREA BASED ON CURRENT SFC OBS AND LOCATION OF
THE COLD FRONT. REF MCD 1628 FOR MORE DETAILS.

...OH VALLEY TO LOWER MO VALLEY/OZARKS...

ONLY MINOR CHANGES WERE MADE THE GENERAL THUNDERSTORM LINE AND 5
PERCENT WIND AREA BASED ON CURRENT LOCATION OF THE COLD FRONT.

..LEITMAN.. 08/27/2014

.PREV DISCUSSION... /ISSUED 1117 AM CDT WED AUG 27 2014/

...SYNOPSIS...

A MID TO UPPER-LEVEL LOW OVER THE ERN GREAT BASIN/CNTRL ROCKIES WILL
GRADUALLY EVOLVE INTO AN OPEN WAVE AS THE SYSTEM SLOWLY EDGES INTO
THE CNTRL HIGH PLAINS. ELSEWHERE...A SHORT-WAVE TROUGH OVER THE
UPPER GREAT LAKES WILL PROGRESS THROUGH NEW ENGLAND WITHIN THE BASE
OF A LARGER-SCALE TROUGH MOVING THROUGH ERN CANADA.

AT THE SURFACE...A LEE CYCLONE WILL PERSIST OVER ERN CO TODAY BEFORE
DEVELOPING INTO WRN KS OVERNIGHT. AN ASSOCIATED WARM FRONT WILL
SLOWLY MOVE NWD INTO THE MID MO VALLEY...WHILE THE ERN PORTION OF
THIS BOUNDARY SETTLES SEWD THROUGH THE NERN U.S. AS A COLD FRONT.

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

MORNING WATER VAPOR IMAGERY DEPICTS A WEAK MID-LEVEL PERTURBATION
OVER CNTRL KS WHICH SHOULD CONTINUE NEWD INTO THE MID MO VALLEY
TODAY. IN ITS WAKE...BREAKS IN THE CLOUDS COUPLED WITH DEWPOINTS
LARGELY IN THE 60S WILL CONTRIBUTE TO POCKETS OF MODERATE
INSTABILITY WITH MLCAPE APPROACHING 1000-1500 J/KG. SCATTERED
SURFACE-BASED TSTMS ARE EXPECTED TO DEVELOP THIS AFTERNOON AHEAD OF
THE ERN CO SURFACE LOW AND WITHIN A CORRIDOR OF ENHANCED UPSLOPE
FLOW OVER NERN CO AS HEIGHT FALLS/DCVA INCREASE WITH THE APPROACH OF
THE CNTRL ROCKIES TROUGH.

THE COMBINATION OF MODERATE INSTABILITY AND A VERTICALLY VEERING
WIND PROFILE WITH 30-35 KT OF DEEP-LAYER SHEAR WILL SUPPORT
ORGANIZED/ROTATING STORMS CAPABLE OF LOCALLY DAMAGING WINDS...SOME
HAIL AND PERHAPS A COUPLE TORNADOES INTO THIS EVENING.

...NORTHEAST THIS AFTERNOON/EVENING...

LOW-LEVEL CONVERGENCE ALONG THE COLD FRONT WILL BE AUGMENTED BY
HEIGHT FALLS/DCVA ATTENDANT TO THE MIGRATORY SHORT-WAVE TROUGH TO
FOSTER A BROKEN BAND OF TSTMS BY AFTERNOON. WHILE MIDLEVEL LAPSE
RATES WILL REMAIN WEAK...DAYTIME HEATING AND BOUNDARY-LAYER
DEWPOINTS IN THE 60S WILL YIELD AFTERNOON MLCAPE OF 500-1500 J/KG
AHEAD OF THE FRONT. WHEN COUPLED WITH A STEADILY STRENGTHENING MID
TO UPPER-LEVEL WIND FIELD...THE ENVIRONMENT MAY BECOME SUPPORTIVE OF
A FEW STRONG TO MARGINALLY SEVERE STORMS CAPABLE OF MAINLY STRONG
WIND GUSTS.

...OH VALLEY TO LOWER MO VALLEY/OZARKS THIS AFTERNOON/EVENING...

LARGE-SCALE FORCING FOR ASCENT WILL REMAIN NEGLIGIBLE OWING TO THE
CLOSE PROXIMITY OF THE UPPER RIDGE. HOWEVER...THE PRESENCE OF THE
SYNOPTIC FRONT AND RESIDUAL OUTFLOW BOUNDARIES WILL LIKELY SERVE AS
FOCI FOR DIURNALLY ENHANCED TSTM DEVELOPMENT. ABUNDANT SUNSHINE AND
THE PRESENCE OF A VERY MOIST AIR MASS WILL PROMOTE MODERATE TO
STRONG AFTERNOON INSTABILITY /MLCAPE OF 1500-3000+ J PER KG/ AND THE
POTENTIAL FOR STRONG UP/DOWNDRAFTS CAPABLE OF LOCALLY DAMAGING WIND
GUSTS AND PERHAPS SOME HAIL.



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