Day 4-8 Convective Outlook Issued on Apr 17, 2011
Updated: Sun Apr 17 08:58:03 UTC 2011
|D4||Wed, Apr 20, 2011 - Thu, Apr 21, 2011
||D7||Sat, Apr 23, 2011 - Sun, Apr 24, 2011
|D5||Thu, Apr 21, 2011 - Fri, Apr 22, 2011
||D8||Sun, Apr 24, 2011 - Mon, Apr 25, 2011
|D6||Fri, Apr 22, 2011 - Sat, Apr 23, 2011
||(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 170858
SPC AC 170858
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0358 AM CDT SUN APR 17 2011
VALID 201200Z - 251200Z
PER 00Z ECMWF/GEFS/UKMET GUIDANCE...A RELATIVELY LOW AMPLITUDE/FAST
MOVING BELT OF WEST-SOUTHWESTERLY MID/UPPER FLOW IS EXPECTED TO
PREVAIL THROUGH THE MIDDLE/LATE PART OF THE UPCOMING WEEK. AS
TYPICAL OF SUCH A LOW AMPLITUDE LONGWAVE REGIME...SPECIFIC
PREDICTABILITY BEGINS TO WANE ESPECIALLY INTO DAYS 5-7. OF
NOTE...THE 00Z GEFS/DETERMINISTIC GFS ARE MORE AMPLIFIED WITH A DAY
5-7 WESTERN/CENTRAL CONUS UPPER TROUGH AS COMPARED TO THE 00Z
ECMWF/UKMET...WITH UNCERTAIN RAMIFICATIONS ON THE
LIKELIHOOD/MAGNITUDE OF SEVERE POTENTIAL IN THIS TIME FRAME.
ON THE HEELS OF WHAT IS EXPECTED TO BE AN ACTIVE DAY 3/TUESDAY...AT
LEAST SOME SEVERE THREAT MAY PERSIST INTO DAY 4/WEDNESDAY ACROSS THE
NORTHEAST STATES ATTENDANT TO THE ADVANCING UPPER TROUGH/FAST MOVING
COLD FRONT. LIMITED /OR AT LEAST UNCERTAIN/ DESTABILIZATION OWING TO
THE EXTENT OF REMNANT DAY 3 CONVECTION PRECLUDES CONSIDERATION OF A
SEVERE RISK AREA.
FOR DAY 5/THURSDAY...THE SOUTH-CENTRAL PLAINS COULD BE A FOCUS FOR
SEVERE TSTMS AS LOW LEVEL MOISTURE GRADUALLY RETURNS TOWARD A
DEVELOPING SOUTH-CENTRAL PLAINS SURFACE LOW AND DRYLINE.
HOWEVER...THE DEGREE OF LARGE SCALE FORCING /AMID LOW AMPLITUDE
SOUTHWESTERLY FLOW ALOFT/ COINCIDENT WITH THE WARM/MOIST SECTOR
CURRENTLY SEEMS QUESTIONABLE.
BY DAY 6/FRIDAY...A MORE WIDESPREAD SEVERE THREAT MAY EVOLVE ACROSS
A CORRIDOR FROM THE SOUTH-CENTRAL PLAINS TO THE MIDDLE MS RIVER
VALLEY VICINITY...ESPECIALLY IF A MORE AMPLIFIED WESTERN STATES
TROUGH MATERIALIZES AS PER 00Z GEFS GUIDANCE.
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