SPC AC 090553
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1153 PM CST MON MAR 08 2010
VALID 091200Z - 101200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
UPPER LOW OVER THE CENTRAL U.S. IS PROGGED TO SHIFT NWD/NEWD WITH
TIME THIS PERIOD...AS A SECOND MOVES QUICKLY SEWD OUT OF CA/NV AND
ACROSS AZ AND NM THROUGH THE PERIOD.
AT THE SURFACE...CYCLOGENESIS IS PROGGED INVOF ERN NM -- S AND W OF
THE INITIAL LOW WHICH SHOULD BE MOVING NEWD TOWARD MO/IA -- AS THE
SECOND UPPER SYSTEM APPROACHES THE SRN HIGH PLAINS LATE. CONVECTION
IS EXPECTED ACROSS PARTS OF THE CENTRAL PLAINS AND INTO THE MS
VALLEY REGION AHEAD OF THE INITIAL SYSTEM...WITH STORMS ALSO LIKELY
ACROSS THE FOUR CORNERS REGION AND VICINITY AS THE SECOND SYSTEM
CROSSES THIS REGION. FINALLY...CONVECTION WILL ALSO AFFECT COASTAL
PARTS OF THE PAC NW...AS A SHARP SHORT-WAVE TROUGH MOVES ONSHORE.
...LOWER MS VALLEY REGION...
KINEMATIC AND THERMODYNAMIC ENVIRONMENT SUPPORTIVE OF AT LEAST SOME
SEVERE WEATHER POTENTIAL SHOULD EVOLVE ACROSS PARTS OF LA/AR/MS
DURING THE AFTERNOON...AS LOW-LEVEL THETA-E ADVECTION CONTINUES ON
SLY BOUNDARY-LAYER FLOW. AREA POINT FORECAST SOUNDINGS FROM VARIOUS
MODELS APPEAR SUPPORTIVE OF SUPERCELLS AND EVEN SOME TORNADO
POTENTIAL.
HAVING SAID THAT...LIKELIHOOD FOR STORM DEVELOPMENT REMAINS
QUESTIONABLE...AS THE UPPER LOW LIFTS NWD INTO THE MID MO VALLEY
REGION. THE ASSOCIATED SURFACE LOW...INITIALLY OVER THE KS/OK
VICINITY...IS ALSO EXPECTED TO SHIFT AWAY FROM THE LOWER MS
VALLEY...MOVING NEWD INTO NRN MO/SRN IA BY THE END OF THE PERIOD.
TRAILING SWD...THE WEAK/ILL-DEFINED TROUGH/FRONT IS PROGGED TO SHIFT
EWD INTO WRN AR/ERN TX THROUGH THE DAY...LARGELY WASHING OUT DURING
THE LATE AFTERNOON/EARLY EVENING AS THE PARENT LOW SHIFTS NEWD. THE
LATEST HI-RES WRF RUN -- LIKELY DUE TO THE LACK OF A SURFACE FOCUS
-- DOES NOT INITIATE APPRECIABLE CONVECTION ACROSS THIS REGION AFTER
EARLIER/WARM ADVECTION-TYPE CONVECTION SHIFTS EWD/NEWD AWAY FROM THE
AREA. WHILE NAM/GFS RUNS DO INITIATE CONVECTION ACROSS THE
REGION...AMOUNTS ARE LIGHT -- WHICH HINTS AT ONLY ISOLATED COVERAGE.
GIVEN THE ABOVE FACTORS...WILL MAINTAIN ONLY LOW SEVERE WEATHER
PROBABILITIES...AS THE UNCERTAINTY REGARDING POTENTIAL FOR/DEGREE OF
CONVECTIVE DEVELOPMENT REMAINS A CONCERN. IF GREATER DEVELOPMENT OF
DEEP/SUSTAINED CONVECTION OCCURS THAN WHAT IS CURRENTLY
ANTICIPATED...THE KINEMATIC AND THERMODYNAMIC ENVIRONMENT WOULD
SUPPORT AN UPGRADE TO SLIGHT RISK.
...FAR ERN KS AND ADJACENT WRN AND CENTRAL MO...
COOL AIR ALOFT ASSOCIATED WITH THE UPPER LOW SHOULD PROVIDE
SUFFICIENT INSTABILITY FOR THE MAINTENANCE OF PERSISTENT CONVECTION
ACROSS THIS REGION. HOWEVER...THE DEGREE OF INSTABILITY WILL LIKELY
REMAIN INSUFFICIENT FOR APPRECIABLE SEVERE WEATHER POTENTIAL...GIVEN
A RELATIVELY COOL BOUNDARY LAYER AND MODEST SURFACE DEWPOINTS.
WHILE A STRONGER CELL OR TWO DURING THE AFTERNOON COULD PRODUCE A
COLD AIR FUNNEL OR EVEN BRIEF/WEAK TORNADO...THREAT APPEARS MINIMAL
ATTM.
..GOSS/GARNER.. 03/09/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
|
