|Day 4-8 Severe Weather Outlook Issued on Jan 25, 2013|
|Updated: Fri Jan 25 09:21:02 UTC 2013|
|D4||Mon, Jan 28, 2013 - Tue, Jan 29, 2013
||D7||Thu, Jan 31, 2013 - Fri, Feb 01, 2013
|D5||Tue, Jan 29, 2013 - Wed, Jan 30, 2013
||D8||Fri, Feb 01, 2013 - Sat, Feb 02, 2013
|D6||Wed, Jan 30, 2013 - Thu, Jan 31, 2013
||(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 a 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 highly unlikely during the entire period (e.g. less than a 30% probability for a regional severe storm area across the CONUS through the entire Day 4-8 period).
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 250920
SPC AC 250920
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0320 AM CST FRI JAN 25 2013
VALID 281200Z - 021200Z
GENERAL AGREEMENT EXISTS AMONGST THE GFS/EC/UK/CMC GLOBAL MODELS IN
THE EVOLUTION OF A LARGE SCALE POSITIVE TILT TROUGH ACROSS THE WRN
U.S. THROUGH D4/MON. HOWEVER...IT IS IMMEDIATELY THEREAFTER AND
BEYOND WHEN SUBSTANTIAL DIFFERENCES APPEAR AND PERSIST AMONGST THE
MEDIUM RANGE GUIDANCE...THUS INTRODUCING CONSIDERABLE UNCERTAINTY IN
THE FORECAST FOR NEXT WEEK.
THE ECMWF EXHIBITS THE GREATEST DEPARTURE FROM PRIOR RUNS AND IS AN
OUTLIER IN DEVELOPING A CUTOFF LOW WITHIN THE BASE OF THE POSITIVE
TILT TROUGH ACROSS THE SOUTHWEST AND BAJA THROUGH D5/TUE. THE
GFS...AND TO SOME EXTENT THE OTHER GLOBAL MODELS AND GFS
ENSEMBLE...MAINTAIN A MORE PROGRESSIVE AND PHASED DEEP UPPER TROUGH
AND STRONGER COLD FRONT THAT SPREAD EAST AND SOUTH ACROSS MID/LOWER
MS VALLEY THROUGH D6/WED. BUT...EVEN AMONGST THE GFS ENSEMBLE
MEMBERS...UNCERTAINTY IN THE AMPLITUDE OF THIS TROUGH IS HIGH WITH
THE STANDARD DEVIATION IN 500MB HEIGHTS ACROSS THE CNTRL U.S.
EXCEEDING 90M AT THE 120H FORECAST VALID D5/TUE EVENING.
DESPITE THE SPREAD IN GFS ENSEMBLE MEMBERS...THERE REMAINS A LOW
PROBABILITY SEVERE WEATHER THREAT FROM ARKLATEX TO MS DELTA REGIONS
AS THE COLD FRONT ASSOCIATED WITH THE UPPER TROUGH DEVELOPS INTO AN
AXIS OF POTENTIAL INSTABILITY THROUGH D5/TUE EVENING. WITH LATEST
MODEL SOLUTIONS AND ENSEMBLE MEMBERS EXHIBITING SUCH DIVERGENT
OUTCOMES HOWEVER...FORECAST CONFIDENCE IN A MORE WIDESPREAD SEVERE
WEATHER THREAT HAS DECREASED SINCE YESTERDAY. THUS...PREDICTABILITY
APPEARS TOO LOW TO MAINTAIN A SEVERE WEATHER AREA AT THIS TIME.
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