SWODY1
SPC AC 230058
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0758 PM CDT WED APR 22 2009
VALID 230100Z - 231200Z
...THERE IS A SLGT RISK OF SVR TSTMS SMALL PORTION OF SRN KS...
...SYNOPSIS...
UPPER AIR PATTERN REMAINS CHARACTERIZED BY RELATIVELY HIGHLY
AMPLIFIED NRN STREAM INVOF CANADIAN BORDER...AND SRN STREAM WITH
SEVERAL WEAK/EMBEDDED SHORTWAVE TROUGHS. HEIGHT FALLS ARE FCST
THROUGH REMAINDER PERIOD AS DEEP/BROAD UPPER CYCLONE MOVED FROM
MID-ATLANTIC REGION TO NEW ENGLAND. MEANWHILE POSITIVELY TILTED
TROUGH WILL MOVE EWD FROM PRESENT POSITION OVER N-CENTRAL AB...SWRN
BC AND PACIFIC WATERS OFFSHORE WA/ORE. SMALL BUT WELL-DEFINED SRN
STREAM PERTURBATION -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER
SWRN KS -- SHOULD MOVE EWD TO ESEWD VICINITY KS/OK BORDER THROUGH
REMAINDER PERIOD. MEANWHILE....BROADER BUT FAIRLY WEAK UPPER LOW
WILL MOVE FROM SERN CA TO WRN AZ.
AT SFC...COMPLEX PATTERN OF OUTFLOW BOUNDARIES AND WARM FRONT PASSES
THROUGH OR VERY NEAR LOW LOCATED OVER SWRN KS. DIFFUSE WARM FRONT
IS DRAWN ESEWD ACROSS NERN OK...AND SHOULD LIFT NWD ACROSS KS/OK
LINE OVERNIGHT AS LOW MOVES SLOWLY EWD.
...KS...
TWO PRIMARY OUTFLOW BOUNDARIES ARC FROM KIOWA-MEADE-HASKELL/FINNEY
COUNTIES KS AS OF 00Z...EXPANDING RADIALLY. THIS BOUNDARY SHOULD
DECELERATE THROUGH SUNSET EXCEPT INVOF CONVECTION NEAR ITS ERN
SEGMENT...AND IS BEING OVERTAKEN BY NEXT OUTFLOW OVER FINNEY COUNTY.
ANOTHER OUTFLOW BOUNDARY WAS MOVING SEWD ACROSS NESS/FINNEY/KEARNY
COUNTIES...FROM HIGH-BASED ACTIVITY IN NWRN KS. WIDELY SCATTERED
TSTMS HAVE BEEN DEVELOPING DURING PAST FEW HOURS INVOF SFC LOW AND
ALONG AND N OF OUTFLOW BOUNDARIES...WITH INTERMITTENT SVR HAIL OVER
A SMALL PART OF SWRN KS. OUTFLOW INTERSECTIONS SHOULD HELP TO
SUSTAIN POTENTIAL FOR NEAR SFC-BASED CONVECTIVE DEVELOPMENT FOR
ANOTHER HOUR OR TWO...BEFORE BOUNDARY LAYER DECOUPLES IN WARM SECTOR
AND LLJ STRENGTHENS APPRECIABLY. CONVECTION SHOULD INCREASE IN
COVERAGE DURING REMAINDER EVENING...BOOSTING HAIL RISK SOMEWHAT.
LLJ AND ACCOMPANYING REGIME OF MAXIMIZED LOW LEVEL WAA AND MOISTURE
TRANSPORT -- WITH MRGL BUT ADEQUATE MOISTURE CONTENT -- WILL SUPPORT
PARCELS BEING RAISED ISENTROPICALLY TO LFC. THROUGH ABOUT
04Z-06Z...THIS REGIME SHOULD SHIFT EWD/NEWD SLIGHTLY...NEARLY
JUXTAPOSED WITH MAXIMUM COOLING ALOFT ASSOCIATED WITH MID-UPPER
PERTURBATION. TROUGH ALOFT THEN SHOULD CONTINUE TO MOVE E WHILE LOW
LEVEL INSTABILITY WEAKENS.
IN ADDITION TO ONGOING HAIL RISK...CONDITIONAL AND BRIEF TORNADO
POTENTIAL MAY EXIST FOR ANY STORM REMAINING ALONG ERN SEGMENT OF
LEADING OUTFLOW BOUNDARY. THAT ENVIRONMENT WILL REMAIN
CHARACTERIZED BY RELATIVELY MAXIMIZED BOUNDARY LAYER
VORTICITY...BACKED SFC WINDS ENHANCED 0-1 KM AGL HODOGRAPHS...AND
LCL LOWERS BECAUSE OF LOSS OF STG SFC HEATING/MIXING.
HOWEVER...OFFSETTING FACTORS INCLUDE THAT SAME COOLING TENDENCY --
WHICH WILL LEAD TO CONSIDERABLE STRENGTHENING OF SBCINH IN NEXT 2-3
HOURS...AS WELL AS RELATIVELY WEAK MID-UPPER WINDS RESULTING IN
ADVERSE STORM-SCALE PRECIP DISTRIBUTION AND LIMITED EFFECTIVE SHEAR.
..EDWARDS.. 04/23/2009
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