Severe Storm Outlook Narrative (AC)
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000
ACUS48 KWNS 280951
SWOD48
SPC AC 280950

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0350 AM CST SUN DEC 28 2014

VALID 311200Z - 051200Z

...DISCUSSION...
LOW-THETAE AIR MASS...RELATED TO LARGE/POST-FRONTAL LOW-LEVEL
ANTICYCLONE E OF ROCKIES...IS EXPECTED TO SUPPRESS SEVERE POTENTIAL
DURING REMAINDER OF 2014 AND AT LEAST THROUGH DAY 5.  STG SHORTWAVE
TROUGH AND RELATED CLOSED LOW OVER WRN CONUS -- DISCUSSED IN DAY-2
AND DAY-3 OUTLOOKS...IS EXPECTED TO EJECT EWD ACROSS 4-CORNERS
REGION AND TOWARD ROCKIES AND PERHAPS SRN HIGH PLAINS BY DAY
6/2ND-3RD.  STG AGREEMENT EXISTS BETWEEN OPERATIONAL SPECTRAL/ECMWF
ON FASTER SRN-PLAINS POSITION LATE DAY 6 INTO DAY 7/3RD-4TH...THOUGH
MOST MREF MEMBERS LIE BETWEEN THAT SOLUTION AND RELATIVELY SLOW
UKMET.  THIS TRANSLATES TO LARGE SPREAD IN LOW-LEVEL MASS
FIELDS...INCLUDING POSITION/GEOMETRY OF INTENSE SFC CYCLONE AND
RELATED COLD FRONT.  GIVEN THOSE FACTORS...ALONG WITH UNCERTAINTY
REGARDING QUALITY OF GULF MOISTURE RETURN...PREDICTABILITY OF ANY
POTENTIAL 15%-SVR AREAS IS TOO LOW FOR OUTLOOK ATTM.

BY DAY 8...SHORTWAVE TIMING DIFFERENCES AMONGST PROGS BECOME
GREATER...THOUGH GENERAL CONSENSUS IS APPARENT ON NEWD EJECTION AND
WEAKENING OF EJECTING SHORTWAVE TROUGH AS LONGWAVE TROUGH DEVELOPS
OVER CENTRAL CONUS.

..EDWARDS.. 12/28/2014


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