Monday, April 21, 2008

DAY48SVR: Nws Storm Prediction Center Norman Ok

ACUS48 KWNS 210857
SWOD48
SPC AC 210857

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0357 AM CDT MON APR 21 2008

VALID 241200Z - 291200Z

...DISCUSSION...

MREF...GFS AND ECMWF ARE IN REASONABLE AGREEMENT THROUGH DAY 4 WITH
EVOLUTION OF UPPER PATTER...BUT BEGIN TO DIVERGE BY DAY 6.

ON DAY 4 THE COMPACT UPPER JET MAX FORECAST TO MOVE THROUGH THE SRN
PLAINS WEDNESDAY WILL CONTINUE NEWD THROUGH THE MID MS VALLEY AND
UPPER GREAT LAKES AREA THURSDAY. STRONG LOW-MID LEVEL WIND FIELDS
AND VERTICAL SHEAR WILL ACCOMPANY THIS FEATURE AND CONTRIBUTE TO A
THREAT FOR SEVERE STORMS...MAINLY OVER A PORTION OF THE MID MS
VALLEY. HOWEVER...UNCERTAINTY REGARDING DESTABILIZATION POTENTIAL
PRECLUDES INTRODUCING AN OUTLOOK AREA AT THIS TIME. OTHER STORMS
WILL LIKELY DEVELOP ALONG SEWD ADVANCING FRONT FROM THE CNTRL AND
NRN PLAINS NEWD INTO THE UPPER MS VALLEY. WHILE A FEW STRONG TO
SEVERE STORMS MAY BE POSSIBLE...INSTABILITY MAY BE A LIMITING
FACTOR.

THE FRONT WILL LIKELY CONTINUE EWD INTO THE OH VALLEY AND SWD
THROUGH THE SRN PLAINS DAY 5. SOME SEVERE STORMS MAY BE POSSIBLE IF
STORMS DEVELOP ALONG PORTION OF THE FRONT MOVING THROUGH THE SRN
PLAINS WHERE INSTABILITY WILL BE GREATER. HOWEVER...THIS PORTION OF
THE BOUNDARY WILL LIKELY SHIFT SOUTH OF THE STRONGER FLOW ALOFT.
INSTABILITY WILL PROBABLY BE A LIMITING FACTOR WITH STORMS MOVING
THROUGH THE GREAT LAKES AND OH VALLEY.

BEYOND DAY 5 DETERMINISTIC MODEL SOLUTIONS MREF MEMBERS BEGIN TO
DIVERGE AS THE ECMWF AMPLIFIES AN UPPER TROUGH OVER THE ERN STATES
MORE STRONGLY THAN THE GFS. IN EITHER CASE...OVERALL UPPER PATTERN
SUGGEST SEVERE POTENTIAL WILL BE LIMITED DAY 6-8.

..DIAL.. 04/21/2008

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@PO.UIUC.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.

No comments: