Day 4-8 Severe Weather Outlook Issued on Nov 21, 2013
Updated: Thu Nov 21 09:46:03 UTC 2013
Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
D4
Sun, Nov 24, 2013 - Mon, Nov 25, 2013
D7
Wed, Nov 27, 2013 - Thu, Nov 28, 2013
D5
Mon, Nov 25, 2013 - Tue, Nov 26, 2013
D8
Thu, Nov 28, 2013 - Fri, Nov 29, 2013
D6
Tue, Nov 26, 2013 - Wed, Nov 27, 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).
Forecast Discussion
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 210944
SPC AC 210944
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0344 AM CST THU NOV 21 2013
VALID 241200Z - 291200Z
...DISCUSSION...
DAYS 4-5...SEVERE POTENTIAL SHOULD REMAIN LOW THROUGH DAY 4 AND MOST
OF DAY 5 OWING TO A COUPLE OF INTRUSIONS OF CP AIR ACCOMPANYING
EXPANSIVE AREAS OF HIGH PRESSURE BUILDING SEWD THROUGH THE ERN HALF
OF THE COUNTRY.
LATE DAY 5 THROUGH DAY 6...THOUGH SOME TIMING AND AMPLITUDE
DIFFERENCES STILL EXIST...ECMWF...GFS AND MOST ENSEMBLE MEMBERS HAVE
CONVERGED ON SIMILAR SOLUTIONS REGARDING THE EJECTION OF SWRN U.S.
UPPER LOW THROUGH THE GULF COASTAL STATES. IT STILL APPEAR THIS WAVE
WILL BEGIN TO AFFECT THE GULF COAST BY LATE DAY 5 INTO DAY 6. THE
ATTENDANT CYCLOGENESIS SHOULD RESULT IN A RETURN OF PARTIALLY
MODIFIED GULF AIR INTO THE CNTRL GULF COAST STATES MAYBE AS EARLY AS
LATE DAY 5 AND THE FL PANHANDLE...SRN GA AND POSSIBLY THE COASTAL
CAROLINAS DAY 6 AS THE LOW REDEVELOPS ALONG THE SERN ATLANTIC
SEABOARD. DEGREE OF ANY SEVERE THREAT WITH THIS EJECTING WAVE STILL
REMAINS UNCERTAIN AT THIS TIME DUE TO LINGERING QUESTIONS REGARDING
THE QUALITY AND EXTENT OF INLAND MOISTURE RETURN AND RESULTING
INSTABILITY. HOWEVER...THIS AREA WILL CONTINUE TO BE MONITORED FOR A
POSSIBLE CATEGORICAL RISK IN LATER OUTLOOKS.
DAYS 7-8...SEVERE POTENTIAL WILL BE LOW AS ANOTHER EXPANSIVE AREA OF
CP HIGH PRESSURE BUILDS THROUGH THE ERN HALF OF THE NATION IN WAKE
OF THE FRONT EXITING THE SERN ATLANTIC SEABOARD.
..DIAL.. 11/21/2013
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