SWOD48
SPC AC 070957
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0357 AM CST SAT FEB 07 2009
VALID 101200Z - 151200Z
...SEVERE STORMS ARE POSSIBLE ACROSS THE SOUTH CENTRAL INTO PARTS OF
THE SOUTHEASTERN STATES THIS COMING TUESDAY/WEDNESDAY...
THE SECOND IN A SERIES OF SIGNIFICANT SHORT WAVE IMPULSES...WITHIN A
PROMINENT SOUTHERN BRANCH OF SPLIT POLAR WESTERLIES...IS PROGGED TO
RAPIDLY LIFT OUT OF THE FOUR CORNERS STATES DURING THE EARLY TO
MIDDLE PORTION OF THE COMING WORK WEEK. MEDIUM RANGE FORECAST
GUIDANCE INDICATES THAT THIS WILL SUPPORT STRONG NEW SURFACE
CYCLOGENESIS ACROSS THE SOUTHERN PLAINS...AS IT TRACKS TO THE LEE OF
THE ROCKIES AT A MORE SOUTHERN LATITUDE THAN THE PRIOR SYSTEM.
CLOSER PROXIMITY TO THE GULF OF MEXICO...COUPLED WITH A CONTINUED
GRADUAL MOISTENING OF THE BOUNDARY LAYER...IS EXPECTED TO SUPPORT
INCREASING CONVECTIVE POTENTIAL...INCLUDING A CONSIDERABLE RISK FOR
SEVERE STORMS. THIS MAY COMMENCE LATE TUESDAY AFTERNOON ACROSS
PARTS OF THE SOUTHERN PLAINS...WHERE A SIZABLE NUMBER OF MREF
MEMBERS INDICATE MIXED LAYER CAPE MAY APPROACH 1000 J/KG IN THE
PRESENCE OF STRONG DEEP LAYER AND LOW-LEVEL SHEAR. GIVEN
INSTABILITY AND FAVORABLE LARGE-SCALE FORCING FOR UPWARD VERTICAL
MOTION...AN EXTENSIVE SQUALL LINE APPEARS POSSIBLE FROM PARTS OF THE
SOUTHEASTERN PLAINS INTO THE LOWER MISSISSIPPI VALLEY TUESDAY NIGHT
INTO EARLY WEDNESDAY.
IT APPEARS PROBABLE THAT THE MID-LEVEL SYSTEM AND ASSOCIATED CYCLONE
WILL CONTINUE TRACKING NORTHEASTWARD INTO AND THROUGH THE OHIO
VALLEY DURING THE DAY WEDNESDAY. WHILE THIS WOULD LEAD TO WEAKENING
LARGE-SCALE LIFT ACROSS THE GULF STATES...STRONG WESTERLY MEAN FLOW
IN EXCESS OF 50 KT MAY ADVECT THE SQUALL LINE THROUGH MUCH OF THE
EASTERN GULF STATES WITH A RISK FOR DAMAGING WINDS...BEFORE ACTIVITY
WEAKENS IN A MORE STABLE ENVIRONMENT. GIVEN THE POSSIBILITY THAT A
SIGNIFICANT CONVECTIVE SYSTEM MAY CUT-OFF NORTHWARD GULF MOISTURE
RETURN...SEVERE POTENTIAL WITHIN THE ZONE OF STRONG FORCING...IN THE
WARM SECTOR OF THE CYCLONE AS IT PROGRESSES THROUGH THE OHIO
VALLEY...IS TOO LOW OR UNCERTAIN TO DELINEATE A SEVERE THREAT.
ADDITIONAL SIGNIFICANT IMPULSES ARE FORECAST TO PROGRESS THROUGH THE
STRONG SOUTHERN STREAM THROUGH THE REMAINDER OF THE PERIOD.
BUT...THE SPREAD AMONG MREF MEMBERS BECOMES TOO LARGE TO CONFIDENTLY
DETERMINE ADDITIONAL SEVERE POTENTIAL.
..KERR.. 02/07/2009
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.
No comments:
Post a Comment