Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 030557
SWODY1
SPC AC 030555

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1255 AM CDT MON AUG 03 2015

VALID 031200Z - 041200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE
NORTHEAST AND OH VALLEY VICINITY...

...THERE IS A MRGL RISK OF SVR TSTMS FROM NEW ENGLAND SWWD ACROSS
THE OH VALLEY...AND THEN WWD ACROSS MO/KS INTO THE CENTRAL AND SRN
HIGH PLAINS...

...SUMMARY...
A FEW SEVERE STORMS ARE EXPECTED FROM THE NORTHEAST INTO THE OHIO
VALLEY...ACCOMPANIED BY ISOLATED OCCURRENCES OF SEVERE WIND AND/OR
HAIL DURING THE AFTERNOON. ISOLATED HAIL AND WIND ARE ALSO POSSIBLE
ACROSS PORTIONS OF THE CENTRAL PLAINS AND INTO THE TEXAS PANHANDLE
AREA.

...SYNOPSIS...
A LARGE MID- AND UPPER-LEVEL VORTEX CENTERED INVOF JAMES BAY IS
PROGGED TO DRIFT VERY GRADUALLY EWD THIS PERIOD...WITH ENHANCED
CYCLONIC FLOW/TROUGHING TO RESIDE OVER MUCH OF THE ERN CONUS.
FARTHER W...NEGATIVELY TILTED SHORT-WAVE TROUGHING SHOULD SHIFT NEWD
ACROSS THE ROCKIES/PLAINS THROUGH A BACKGROUND/LONGER-WAVELENGTH
MEAN RIDGE.

AT THE SURFACE...A WEAKENING COLD FRONT TRAILING SWD/SWWD FROM A WRN
QUEBEC LOW IS FORECAST TO SHIFT EWD ACROSS THE NORTHEAST U.S. AND
SEWD INTO THE OH VALLEY/MIDWEST REGION...AND THEN WWD ACROSS MO AND
KS AND INTO THE CENTRAL HIGH PLAINS.  THIS FRONT WILL FOCUS
CONVECTION/ISOLATED SEVERE RISK THROUGH THE PERIOD.

...PORTIONS OF NEW ENGLAND SWWD INTO THE OH VALLEY...
AS A WEAKENING COLD FRONT MOVES SLOWLY EWD ACROSS THE NORTHEAST U.S.
DURING THE DAY...GRADUAL DEVELOPMENT OF SCATTERED SHOWERS AND
THUNDERSTORMS IS EXPECTED TO OCCUR...AS DIURNAL HEATING PUSHES
MIXED-LAYER CAPE INTO THE 1000 TO 2000 J/KG RANGE ACROSS THE
NORTHEAST/NEW ENGLAND...AND IN EXCESS OF 3000 J/KG INTO THE MID-OH
VALLEY REGION.

WITH A BELT OF ENHANCED/CYCLONIC LOW- TO MID-LEVEL SWLYS PROGGED TO
RESIDE ACROSS THE REGION...A FEW STRONGER STORMS ARE EXPECTED --
THOUGH FLOW LARGELY PARALLEL TO THE FRONTAL ZONE AND UNIDIRECTIONAL
WITH HEIGHT SHOULD TEND TO LIMIT THE OVERALL SEVERE POTENTIAL TO
SOME DEGREE.  STILL...STRONGER CELLS ACROSS THE AREA WILL BE CAPABLE
OF PRODUCING MARGINAL HAIL AND/OR DAMAGING GUSTS DURING THE
AFTERNOON AND EARLY EVENING HOURS.

...PORTIONS OF THE CENTRAL AND SRN PLAINS...
SCATTERED SHOWERS AND THUNDERSTORMS ARE FORECAST ACROSS PORTIONS OF
THE CENTRAL AND SRN PLAINS...AS LARGE-SCALE ASCENT ASSOCIATED WITH A
WEAK VORT MAX SHIFTING EWD OUT OF THE CENTRAL ROCKIES IS FOCUSED AT
LOW LEVELS ALONG THE COLD FRONT PROGGED TO LIE W-E ACROSS THE NRN KS
VICINITY AS WELL AS INVOF A LEE TROUGH OVER THE HIGH PLAINS.  WHILE
FLOW ALOFT WILL REMAIN RELATIVELY WEAK ACROSS MOST OF THE AREA --
AND THUS ONLY LIMITED SEVERE THREAT WITH LARGELY DISORGANIZED
STORMS...SLIGHTLY GREATER SHEAR IS EXPECTED WHERE LOW-LEVEL FLOW IS
BACKED -- I.E. JUST E OF THE HIGH-PLAINS LEE TROUGH...AND TO THE
COOL SIDE OF THE SURFACE FRONT.  IN BOTH AREAS...MULTICELL
ORGANIZATION POTENTIAL MAY SUPPORT EVOLUTION OF A FEW STRONGER STORM
CLUSTERS -- ALONG WITH A FEW HAIL/WIND OCCURRENCES APPROACHING OR
EXCEEDING SEVERE LEVELS.

..GOSS/MARSH.. 08/03/2015



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