SWODY3
SPC AC 080828
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0228 AM CST SUN FEB 08 2009
VALID 101200Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS LATE TUE AFTN/TUE NIGHT FROM
PARTS OF THE SRN PLAINS INTO LWR/MID MS VALLEY....
...SYNOPSIS...
CONVECTIVE POTENTIAL...INCLUDING THE RISK FOR SEVERE STORMS...IS
EXPECTED TO INCREASE SUBSTANTIALLY DURING THIS FORECAST PERIOD...AS
THE NEXT IN A SERIES OF STRONG SHORT WAVE TROUGHS LIFTS OUT OF THE
FOUR CORNERS STATES. EAST NORTHEASTWARD ACCELERATION...OUT OF
BROADER SCALE TROUGHING WITHIN THE MAIN BELT OF POLAR WESTERLIES
ACROSS THE SOUTHWESTERN U.S...IS PROGGED...AS YET ANOTHER
SIGNIFICANT IMPULSE DIGS INTO THE NORTH CENTRAL PACIFIC COAST. IN
THE WAKE OF A PRIOR SYSTEM...LIKELY STILL GRADUALLY LIFTING ACROSS
THE INTERNATIONAL BORDER INTO NORTHWEST ONTARIO ON TUESDAY...A MORE
SOUTHERLY TRACK APPEARS LIKELY TO SUPPORT LEE SURFACE CYCLOGENESIS
IN CLOSE ENOUGH PROXIMITY TO THE GULF OF MEXICO TO ALLOW FOR WEAK TO
MODERATE DESTABILIZATION IN THE WARM SECTOR.
ASIDE FROM SOME CONTINUING VARIABILITY AMONG THE MODELS CONCERNING
THE SPEED AT WHICH THE MID-LEVEL SYSTEM SHIFTS EAST OF THE SOUTHERN
ROCKIES THROUGH THE MIDDLE MISSISSIPPI VALLEY...THE PRIMARY
UNCERTAINTY FOR THIS FORECAST CONCERNS LINGERING DOUBTS ABOUT THE
QUALITY OF THE GULF RETURN FLOW. AT THIS TIME...THIS PRECLUDES AN
OUTLOOK OF HIGHER SEVERE PROBABILITIES THAT COULD ACCOMPANY A
SYNOPTIC SYSTEM OF THIS STRENGTH...INCLUDING THE DEVELOPMENT OF A
50-70 KT SOUTHERLY PRE-FRONTAL 850 JET STREAK...BENEATH A 90-100+ KT
WEST SOUTHWESTERLY 500 MB JET STREAK. AND...HIGHEST PROBABILITIES
CURRENTLY INDICATED COULD STILL SHIFT A BIT.
...SOUTHERN PLAINS THROUGH LOWER HALF OF MISSISSIPPI VALLEY...
MODELS CONTINUE TO INDICATE GOOD POTENTIAL FOR THE EVOLUTION OF CAPE
AT LEAST ON THE ORDER OF 500 J/KG BY TUESDAY AFTERNOON...AS LAPSE
RATES STEEPEN ABOVE LOW-LEVEL MOISTURE CHARACTERIZED BY MID 50S TO
AROUND 60F SURFACE DEW POINTS...FROM PARTS OF EASTERN TEXAS INTO THE
OZARK PLATEAU. MID-LEVEL INHIBITION SHOULD BE SUFFICIENTLY STRONG
TO PRECLUDE THE INITIATION OF STORMS PRIOR TO LATE
AFTERNOON...PERHAPS EARLY EVENING. BUT...GUIDANCE IS SUGGESTIVE
THAT A CONFLUENCE ZONE/ZONE OF ENHANCED LOW-LEVEL WARM ADVECTION
NEAR THE INTENSIFYING LOW-LEVEL JET CORE COULD BECOME THE FOCUS FOR
DISCRETE STORMS NEAR OR SHORTLY AFTER DARK ACROSS PARTS OF NORTHEAST
TEXAS AND EASTERN OKLAHOMA INTO WESTERN ARKANSAS. IF THIS
OCCURS...LONG HODOGRAPHS WITH LARGE LOW-LEVEL CLOCKWISE CURVATURE
WILL BE QUITE FAVORABLE FOR SUPERCELLS CAPABLE OF PRODUCING
TORNADOES.
ANY DISCRETE DEVELOPMENT IS EXPECTED TO SPREAD NORTHEASTWARD INTO/
THROUGH THE OZARK PLATEAU TUESDAY EVENING...AS ADDITIONAL STORMS
DEVELOP TO THE WEST...FROM PARTS OF NORTHEAST TEXAS INTO SOUTHEAST
KANSAS. THIS IS EXPECTED TO OCCUR ALONG OR JUST AHEAD OF AN
EASTWARD ADVANCING COLD FRONT...AS STRENGTHENING LINEAR FORCING
ENCOUNTERS THE BETTER MOISTURE ACROSS THE SOUTHEASTERN PLAINS. THE
EVOLUTION OF AN EXTENSIVE SQUALL LINE APPEARS POSSIBLE...ACCOMPANIED
BY THE POTENTIAL FOR STRONG CONVECTIVE GUSTS WITH THE RISK FOR
CONSIDERABLE WIND DAMAGE AS IT SURGES EASTWARD INTO THE LOWER
MISSISSIPPI VALLEY TUESDAY NIGHT.
..KERR.. 02/08/2009
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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