SWODY1
SPC AC 301639
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1139 AM CDT WED MAY 30 2007
VALID 301630Z - 311200Z
..THERE IS A SLGT RISK OF SVR TSTMS ACROSS CENTRAL AND EASTERN
TEXAS....
..THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER MS
VALLEY....
..SYNOPSIS...
LARGE MCS THAT MOVED SSEWD FROM OK INTO N CENTRAL TX IS EXPECTED TO
CONTINUE SEWD THRU THIS AFTERNOON. THIS FEATURE HAS CREATED QUITE A
CHALLENGE FOR FORECASTING THE REMAINDER OF THE DAY1 PERIOD. MODELS
INDICATE THAT LARGE VORTEX WILL DEVELOP OVER SD THIS AFTERNOON THRU
TONIGHT...STALLED DUE TO OMEGA BLOCK OVER THE MID ATLANTIC REGION.
MORNING SURFACE ANALYSIS SHOWS LOW PRESSURE OVER NERN SD WITH
QUASISTATIONARY BOUNDARY NEWD THRU N CENTRAL MN...AND ANOTHER
BOUNDARY EXTENDING SWD ACROSS ERN NEB AND ERN KS. THE CONVECTIVE
OUTFLOW BOUNDARY FROM OK/TX MCS CURRENTLY EXTENDS FROM SWRN AR/NERN
TX WSWWD INTO N CENTRAL TX.
..TX...
THERMAL/MOISTURE AXIS THIS MORNING EXTENDED SSEWD FROM E OF DAL -
BETWEEN HOU/GLS LINE. MESOANALYSIS SHOWS THAT MLCAPE IS 1500-1800
J/KG AND WOULD EXPECT MUCH OF THE BOW ECHO TO TRACK SEWD THRU THIS
AREA INTO EARLY/MID AFTERNOON.
PROBLEM NOW IS TO ESTIMATE WHERE ANY SURFACE HEATING AND
DESTABILIZATION CAN OCCUR FOR THIS AFTERNOON. MODELS GIVE A GENERAL
IDEA THAT THE COLD FRONTAL BOUNDARY WILL BE MOVING SLOWLY EWD/SEWD
THRU NWRN AND ERN PARTS OF W CENTRAL TX WHERE AIR MASS IS MORE
MODERATELY UNSTABLE WITH MLCAPE BETWEEN 2000-2500 J/KG. CURRENTLY
THIS AREA IS AROUND THE MWL-SEP-BWD-DYS AREA. IN ADDITION...THERE
IS SOME DEEP LAYER SHEAR STILL PRESENT JUST N OF THIS AREA WHERE
VALUES ARE 30-40 KT WHICH IS SUFFICIENT TO SUPPORT THE DEVELOPMENT
OF DEEP UPDRAFTS. THUS...WILL EXPECT LINE OF STRONG/SEVERE
THUNDERSTORMS ALONG/AHEAD OF SLOWLY ADVANCING FRONTAL BOUNDARY
ACROSS NWRN TX THIS AFTERNOON AND ADVANCEMENT SHOULD FOCUS ON
CONVECTIVE OUTFLOW BOUNDARY RELATED TO MCS.
..UPPER MS VALLEY...
ALL THE MODELS TAKE SRN PARTS OF MID/UPPER LEVEL LOW AND MOVE IT
NEWD TOWARDS PARTS OF MN AND IA THIS AFTERNOON. STRONG DYNAMIC
FORCING IS QUITE EVIDENT WITH THIS NEGATIVELY TILTED FEATURE AND
COULD GENERATE A LINE OF STRONG/SEVERE CONVECTION ASSOCIATED WITH
THE ADVANCEMENT OF THE BOUNDARY CURRENTLY FROM ERN SD INTO ERN NEB
AND ERN KS. NOTE THAT SURFACE DEW POINTS ARE IN THE LOW/MID 60S
ACROSS THIS REGION...AND VISIBLE SATELLITE IMAGERY SHOWS SUFFICIENT
HEATING AT THIS TIME WITH THE STRONGEST DESTABILIZATION OVER E
CENTRAL MN INTO WI. WHILE MODEL SOUNDINGS ARE SHOWING WEAK
DIRECTIONAL SHEAR...THERE IS SUFFICIENT SPEED SHEAR PRESENT THAT
THERE COULD BE SOME ISOLATED SPIN UPS ASSOCIATED WITH EXPECTED LINE
OF STRONG/SEVERE THUNDERSTORMS. LOOKS AT THIS TIME THAT THE MAIN
THREAT WILL BE DAMAGING WINDS...BUT THERE COULD BE ISOLATED
TORNADOES IN NERN SD/SERN ND INTO WRN MN WHERE THERE WILL BE LOW/MID
LEVEL VORTICITY NEAR THE DEVELOPMENT OF MID/UPPER LEVEL VORTEX
CIRCULATION.
.MCCARTHY/SCHNEIDER.. 05/30/2007
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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 chris@lib.siu.edu.
No comments:
Post a Comment