Severe Storm Outlook Narrative (AC)
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ACUS48 KWNS 270954
SWOD48
SPC AC 270953

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0353 AM CST THU NOV 27 2014

VALID 301200Z - 051200Z

...DISCUSSION...
THE MEDIUM-RANGE MODELS BEGIN THE DAY 4 TO 8 PERIOD WITH A WEST TO
SOUTHWEST FLOW PATTERN IN PLACE ACROSS THE CONUS. ON SUNDAY/DAY
4...THE MODELS MOVE A LOW AMPLITUDE LONGWAVE TROUGH ACROSS THE NRN
STATES AS A COLD FRONT ADVANCES SEWD ACROSS THE MID MS VALLEY AND
SRN PLAINS. THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE ALONG THE
FRONT SUNDAY EVENING OR OVERNIGHT FROM THE OZARKS EWD INTO THE TN
VALLEY. A CHANCE FOR STORMS ALONG THE FRONT MAY CONTINUE TO
MONDAY/DAY 5 AS THE FRONT MOVES SWD ACROSS THE SRN PLAINS AND LOWER
MS VALLEY. ON TUESDAY/DAY 6...THE ECMWF AND GFS SOLUTIONS DIVERGE
SHARPLY. THE ECMWF FORECASTS A LONGWAVE TROUGH OVER MUCH OF THE
CONUS WHILE THE GFS SHOWS ZONAL FLOW OVER THE CNTRL AND ERN STATES.
BOTH SOLUTIONS KEEP LOW-LEVEL MOISTURE IN PLACE ACROSS THE GULF
COAST STATES SUGGESTING THAT THUNDERSTORM DEVELOPMENT COULD OCCUR
THERE TUESDAY AFTERNOON. THE MODEL SOLUTIONS CONTINUE BE VERY
DIFFERENT FOR WEDNESDAY/DAY 7.

ALTHOUGH THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE FROM THE TN
VALLEY SWWD INTO THE SRN PLAINS FROM SUNDAY TO TUESDAY...WEAK
INSTABILITY AND A LACK OF STRONG LARGE-SCALE ASCENT SHOULD KEEP ANY
SEVERE THREAT THAT DEVELOPS RELATIVELY ISOLATED.

..BROYLES.. 11/27/2014



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