Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 200551
SWODY2
SPC AC 200550

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1250 AM CDT SAT SEP 20 2014

VALID 211200Z - 221200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
SCATTERED SHOWERS AND ISOLATED STRONGER THUNDERSTORMS WILL BE
POSSIBLE ACROSS THE EASTERN GREAT LAKES...OHIO VALLEY...AND
NORTHEAST STATES ON SUNDAY. SCATTERED THUNDERSTORMS ARE ALSO
EXPECTED ACROSS THE INTERIOR WEST...THE RIO GRANDE VALLEY...AND OVER
FLORIDA.

...SYNOPSIS...
LARGE-SCALE TROUGH AMPLIFICATION WILL CONTINUE TO OCCUR OVER THE
GREAT LAKES REGION/NORTHEAST STATES FROM LATE TONIGHT INTO SUNDAY.
AN ASSOCIATED COLD FRONT WILL QUICKLY SPREAD EAST-SOUTHEASTWARD FROM
THE LOWER OH VALLEY/MIDDLE MS VALLEY TO THE APPALACHIANS AND
MID-ATLANTIC/NORTHEAST SEABOARD BY EARLY MONDAY. IN THE WESTERN
CONUS...A CLOSED UPPER LOW CURRENTLY NEAR COASTAL SOUTHERN CA WILL
BECOME MORE NORTHEASTWARD-PROGRESSIVE ON SUNDAY AS IT CROSSES THE
GREAT BASIN.

...UPPER OH VALLEY/CENTRAL APPALACHIANS TO NY...
AMPLIFYING UPPER TROUGH WILL CONTRIBUTE TO STEADY HEIGHT FALLS AND
STRONG CYCLONIC MID/UPPER-LEVEL WINDS IN CONJUNCTION WITH AN
ACCELERATING COLD FRONT AND A GRADUALLY DEEPENING SURFACE LOW OVER
THE LOWER GREAT LAKES. MODEST DESTABILIZATION...CHARACTERIZED BY
STEEPENING LOW-LEVEL LAPSE RATES AND MLCAPE POSSIBLY EXCEEDING 1000
J/KG...IS EXPECTED ALONG AND IN ADVANCE OF THE COLD FRONT. FORCED
ASCENT AND RELATIVELY STRONG DEEP-LAYER SHEAR OF 45+ KT SHOULD
CONTRIBUTE TO THE DEVELOPMENT OF NARROW BANDS AND LINES OF
FASTER-MOVING CONVECTION SUNDAY AFTERNOON/EVENING. SOME OF THESE
STORMS COULD PRODUCE SCATTERED STRONGER WIND GUSTS...MAINLY ACROSS
PARTS OF NY/PA/WV/FAR EASTERN OH WHERE THE MOST FAVORABLE
COLLOCATION OF FORCING/SHEAR/WEAK INSTABILITY IS ANTICIPATED.

...GREAT BASIN...
IN ASSOCIATION WITH A NORTHEAST-ADVANCING UPPER LOW...LARGE-SCALE
ASCENT AND A MODERATELY STRONG MID-LEVEL SPEED MAX OF 30-35 KT WILL
OVERSPREAD MUCH OF NV/UT AND NORTHERN AZ SUNDAY AFTERNOON. DIURNALLY
MAXIMIZED HEATING AND EFFECTIVE SHEAR ON THE ORDER OF 30 KT SHOULD
CONTRIBUTE TO THE DEVELOPMENT AND SUSTENANCE OF HIGH-BASED
STORMS...POTENTIALLY INCLUDING A LIMITED POTENTIAL FOR MARGINALLY
SEVERE HAIL AND/OR GUSTY DOWNDRAFT WINDS SUNDAY AFTERNOON/EARLY
EVENING.

..GUYER.. 09/20/2014




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