Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS03 KWNS 230732
SWODY3
SPC AC 230730

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CDT SAT AUG 23 2014

VALID 251200Z - 261200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
A FEW STRONG/ISOLATED SEVERE STORMS WILL BE POSSIBLE ACROSS THE
UPPER GREAT LAKES REGION MONDAY...WHILE ADDITIONAL STORMS EVOLVE
FARTHER TO THE WEST AND WEST-SOUTHWEST ACROSS THE CENTRAL PORTION OF
THE COUNTRY.

...SYNOPSIS...
AS AN UPPER LOW SHIFTING NEWD AWAY FROM THE N CENTRAL U.S. CONTINUES
TO WEAKEN AS IT CROSSES ONTARIO...THE LARGE-SCALE RIDGE IS PROGGED
TO EXPAND ACROSS A LARGE PORTION OF THE SRN AND ERN CONUS.
MEANWHILE...A DOWNSTREAM TROUGH WILL REMAIN OVER THE WRN PORTION OF
THE COUNTRY THROUGH THE PERIOD.

AT THE SURFACE...A COLD FRONT -- TRAILING SWWD FROM A LOW MOVING
NEWD ACROSS ONTARIO TOWARD HUDSON BAY -- WILL ADVANCE EWD ACROSS THE
UPPER GREAT LAKES REGION THROUGH THE DAY.  MEANWHILE...THE WRN
EXTENSION OF THIS BOUNDARY WILL REMAIN MORE QUASISTATIONARY/W-E
ORIENTED ACROSS THE UPPER MIDWEST/CENTRAL PLAINS VICINITY THROUGH
THE PERIOD.

...UPPER GREAT LAKES REGION...
ONGOING STORMS ARE FORECAST AHEAD OF THE ADVANCING COLD FRONT EARLY
IN THE PERIOD...WITH SOME INTENSIFICATION OF CONVECTION POSSIBLE
DURING THE AFTERNOON AS MODEST DESTABILIZATION OCCURS.  WITH
ENHANCED FLOW ALOFT -- ON THE SRN FRINGE OF THE DEPARTING UPPER
SYSTEM -- LYING ACROSS THE UPPER GREAT LAKES...SHEAR SUFFICIENT FOR
STORM ORGANIZATION IS EXPECTED.  THUS...A STRONGER STORM OR TWO MAY
BECOME CAPABLE OF LOCALLY DAMAGING WINDS AND/OR HAIL THROUGH EARLY
EVENING.

...CENTRAL HIGH PLAINS ENEWD ACROSS THE MID MO VALLEY...
RELATIVELY SUBSTANTIAL MODEL-TO-MODEL DIFFERENCES ARE EVIDENT WITH
RESPECT TO EVOLUTION OF THE WRN U.S. TROUGH...WITH THE GFS SHOWING A
MORE PROGRESSIVE FEATURE CROSSING THE ROCKIES AND THEN APPROACHING
THE PLAINS DURING THE SECOND HALF OF THE PERIOD WHILE THE NAM SHOWS
A CUT-OFF -- EVEN SLIGHTLY RETROGRESSIVE -- LOW OVER THE WRN NV/NRN
CA VICINITY.  UPSTREAM DIFFERENCES ACROSS THE PLAINS ARE THUS ALSO
EVIDENT...WITH THE NAM DEPICTING RISING HEIGHTS ACROSS THE CENTRAL
U.S. AND A WEAKENING SURFACE FRONT...WHILE THE GFS SUGGESTS
CYCLOGENESIS OVER THE CENTRAL HIGH PLAINS ALONG THE WRN FRINGE OF
THE SURFACE FRONT.  AS SUCH...THE GFS IS MUCH MORE BULLISH WITH
RESPECT TO POSSIBLE SEVERE RISK...WHILE THE NAM WOULD SUGGEST A
LARGELY SUB-SEVERE/ELEVATED CONVECTIVE EVENT N OF THE FRONT.
ATTM...WILL OPT TO REFRAIN FROM ISSUANCE OF SEVERE PROBABILITIES DUE
TO UNCERTAINTY...WITH THIS AREA TO BE RE-EVALUATED IN LATER
FORECASTS.

..GOSS.. 08/23/2014



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