Severe Storm Outlook Narrative (AC)
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ACUS48 KWNS 150853
SWOD48
SPC AC 150852

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0352 AM CDT MON SEP 15 2014

VALID 181200Z - 231200Z

...DISCUSSION...
THE ECMWF AND GFS MODELS BEGIN THE DAY 4 TO 8 PERIOD WITH AN
UPPER-LEVEL TROUGH ALONG THE EAST COAST AND AN UPPER-LEVEL RIDGE IN
THE CNTRL AND NRN ROCKIES. THE UPPER-LEVEL RIDGE MOVES EWD TOWARD A
CORRIDOR OF LOW-LEVEL MOISTURE IN THE GREAT PLAINS ON THURSDAY/DAY
4. THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE THURSDAY AFTERNOON
ALONG THE MOIST AXIS. ON FRIDAY/DAY 5...THE MODELS FLATTEN THE
UPPER-LEVEL RIDGE AS IT MOVES EWD ACROSS THE UPPER MS VALLEY. THE
GFS MODEL FORECASTS A POCKET OF MODERATE INSTABILITY ACROSS THE NRN
PLAINS AND UPPER MIDWEST FRIDAY AFTERNOON WHERE STRONG TO SEVERE
THUNDERSTORMS WILL BE POSSIBLE. ON SATURDAY/DAY 6...BOTH THE ECMWF
AND GFS MODELS MOVE AN UPPER-LEVEL TROUGH INTO THE MID TO UPPER MS
VALLEY. STRONG THUNDERSTORMS WITH SOME POSSIBLY SEVERE...WOULD BE
POSSIBLE ALONG A CORRIDOR OF INSTABILITY EXTENDING FROM THE CNTRL
PLAINS NNEWD INTO THE UPPER MS VALLEY. ON SUNDAY/DAY 7...MODEL
SOLUTIONS DIVERGE SHARPLY. AT THIS POINT...A NOTABLE SEVERE THREAT
COULD DEVELOP ACROSS PARTS OF THE NCNTRL STATES FROM FRIDAY INTO
SATURDAY. HOWEVER...QUESTIONS CONCERNING THE TIMING OF THE
UPPER-LEVEL TROUGH AND THE AMOUNT OF INSTABILITY REMAIN. FOR THESE
REASONS...WILL NOT OUTLOOK AN AREA ATTM.

..BROYLES.. 09/15/2014



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