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Day 4-8 Convective Outlook Issued on Nov 25, 2009
Updated: Wed Nov 25 09:40:03 UTC 2009
| D4 | Sat, Nov 28, 2009 - Sun, Nov 29, 2009 |
D7 | Tue, Dec 01, 2009 - Wed, Dec 02, 2009 |
| D5 | Sun, Nov 29, 2009 - Mon, Nov 30, 2009 |
D8 | Wed, Dec 02, 2009 - Thu, Dec 03, 2009 |
| D6 | Mon, Nov 30, 2009 - Tue, Dec 01, 2009 |
(All days are valid from 12 UTC - 12 UTC) |
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 250939
SPC AC 250939
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0339 AM CST WED NOV 25 2009
VALID 281200Z - 031200Z
...DISCUSSION...
PROGRESSIVE BUT DECIDEDLY SPLIT FLOW REGIME WILL BE EVIDENT ACROSS
THE COUNTRY IN THE MEDIUM RANGE. PRIMARY FEATURE OF INTEREST WILL
BE THE UPR LVL IMPULSE EXPECTED TO EJECT EWD ACROSS THE SRN PLNS AND
LWR MS VLY ON MON-TUE /DAY 6-7/. 00Z GFS IS STRONGER WITH THE
FEATURE...MAINTAINING SUFFICIENTLY MORE NRN STREAM PHASING AND
RESULTING IN THE TROUGH BEING MORE NEGATIVELY-TILTED. LATEST ECMWF
DETERMINISTIC/MEANS ARE WEAKER WITH THE SYSTEM AND MORE
POSITIVELY-TILTED OWING TO THE MAINTENANCE OF TWO SEPARATE POLAR
BRANCHES. VARIANCE IN THE MODELS ALREADY WOULD ARGUE AGAINST A
HIGHER-END SVR OTLK GIVEN LOW CONFIDENCE AT THAT RANGE.
HOWEVER...THERE ARE ALSO QUESTIONS ON THE QUALITY OF MOISTURE RETURN
SINCE THE GULF OF MEXICO BOUNDARY LAYER WILL TAKE TIME TO MODIFY
AFTER THE DEEP SWD PENETRATION OF THE CDFNT INTO THE GULF BASIN
LATER THIS WEEK.
..RACY.. 11/25/2009
CLICK TO GET WUUS48 PTSD48 PRODUCT
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