Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 210059
SWODY1
SPC AC 210057

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0657 PM CST THU NOV 20 2014

VALID 210100Z - 211200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
OCCASIONAL LIGHTNING REMAINS POSSIBLE WITH LAKE-EFFECT CONVECTIVE
PLUMES IN THE LEE OF LAKES ERIE AND ONTARIO THROUGH EARLY EVENING.

...SYNOPTIC SETUP...
BROAD...TWO-STREAM CYCLONIC FLOW WILL PREVAIL OVER THE CONUS THROUGH
EARLY FRI...DOWNSTREAM FROM PERSISTENT BLOCK N OF AK. MAIN COMPONENT
OF ERN CANADIAN TROUGH WILL FURTHER AMPLIFY SE ACROSS THE GRT LKS
AND NERN STATES AS ASSOCIATED SHORTWAVE TROUGH NOW CROSSING LK
SUPERIOR SWEEPS E TO THE LWR LKS. IN THE SRN BRANCH...A SERIES OF
WEAK DISTURBANCES WILL CROSS THE SWRN STATES AHEAD OF STRONGER E
PACIFIC TROUGH NOW APPROACHING CNTRL CA.

...CNTRL CA...
COLD AIR ALOFT AND FORCING FOR ASCENT WITH A COMPACT SHORTWAVE
TROUGH WILL CONTINUE TO PRODUCE SHOWERS WITH ISOLATED LIGHTNING
STRIKES THIS EVENING. 00Z OAK SOUNDING SHOWS COLD AIR ALOFT WITH EL
HEIGHTS ABOVE THE -20 C LEVEL WHICH IS MARGINALLY SUPPORTIVE OF
LIGHTNING.

...ERN TX INTO THE ARKLATEX...
00Z SOUNDINGS FROM THE REGION CONTINUE TO INDICATE A CAPPING
INVERSION AND VERY DRY AIR ALOFT ATOP A SLOWLY-MOISTENING BOUNDARY
LAYER DESPITE WEAK INSTABILITY. WHILE SOME CONTINUED LOW-LEVEL
MOISTURE WILL CONTINUE OVERNIGHT DUE TO A SLY LOW-LEVEL
JET...CHANCES FOR CONVECTION DEEP ENOUGH TO PRODUCE LIGHTNING ARE
LOW.

..JEWELL.. 11/21/2014



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