(All days are valid from 12 UTC - 12 UTC the following day)
Note: A severe weather area depicted in the Day 4-8 period indicates 15%, 30% or higher probability for severe thunderstorms within 25 miles of any point.
PREDICTABILITY TOO LOW is used to indicate severe storms may be possible based on some model scenarios. However, the location or occurrence of severe storms are in doubt due to: 1) large differences in the deterministic model solutions, 2) large spread in the ensemble guidance, and/or 3) minimal run-to-run continuity.
POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears unlikely (i.e., less than 15%) for the forecast day.
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 210942
SPC AC 210942
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0342 AM CST SUN DEC 21 2014
VALID 241200Z - 291200Z
WEDNESDAY /DAY 4/...MODEL CONSENSUS IS THAT HIGH-AMPLITUDE UPPER
TROUGH WILL CONTINUE TOWARD THE ATLANTIC SEABOARD BEFORE FINALLY
REACHING THE COAST LATER WEDNESDAY NIGHT ALONG WITH ITS ATTENDANT
COLD FRONT. WHILE STRONG DEEP-LAYER WINDS AND VERTICAL SHEAR WILL
ACCOMPANY THIS FEATURE...WIDESPREAD PRECIPITATION IN THE MOIST
PRE-FRONTAL WARM SECTOR LOWERS CONFIDENCE IN A MORE ROBUST SEVERE
THREAT OVER THE CAROLINAS. A FEW SEVERE STORMS WILL ALSO BE POSSIBLE
AS THE COLD FRONT MOVES THROUGH THE FL PENINSULA...AND A RISK AREA
MAY ULTIMATELY BE NEEDED THERE IN LATER UPDATES.
DAY 5-8...SEVERE POTENTIAL WILL REMAIN LOW DAY 5 OWING TO INTRUSION
OF CP AIR INTO THE GULF. LIMITED MOISTURE WILL RETURN NWD INTO ERN
TX AND THE LOWER MS VALLEY DAY 6 AHEAD OF A COLD FRONT AND ATTENDANT
LOW-AMPLITUDE SHORTWAVE TROUGH. AT THIS TIME IT APPEARS LOW-LEVEL
MOISTURE WILL REMAIN INSUFFICIENT FOR A MORE ROBUST SEVERE THREAT.
BEYOND DAY 6 A LARGE AREA OF CP HIGH PRESSURE WILL EVOLVE OVER MUCH
OF THE ERN HALF OF THE COUNTRY AND PROMOTE OFFSHORE FLOW OVER THE
GULF AND STABLE CONDITIONS INLAND.
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