SWODY2
SPC AC 291648
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1148 AM CDT FRI AUG 29 2008
VALID 301200Z - 311200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
LARGE-SCALE PATTERN WILL UNDERGO AMPLIFICATION DURING THE DAY TWO
PERIOD AS LONG WAVE TROUGH INTENSIFIES OVER WRN CANADA/U.S...
SUPPORTING BUILDING OF DOWNSTREAM RIDGE OVER THE UPPER GREAT LAKES
AND ONTARIO.
...CNTRL HIGH PLAINS INTO LOWER MS VALLEY...
WRN EXTENSION OF SURFACE BOUNDARY OVER THE HIGH PLAINS WILL LIFT NWD
THROUGH THE PERIOD IN RESPONSE TO LEE CYCLOGENESIS OVER THE NRN HIGH
PLAINS. FARTHER SE...FRONT WILL CONTINUE SLOWLY SWD AS EXPANSIVE
SURFACE HIGH BUILDS EWD ACROSS THE GREAT LAKES/OH VALLEY.
PRE-FRONTAL AIR MASS IS EXPECTED TO REMAIN QUITE MOIST OVER THE
LOWER MS VALLEY INTO SRN PLAINS WITH DEWPOINTS IN THE 60S TO
LOWER/MID 70S. THIS MOISTURE WILL COMBINE WITH DAYTIME HEATING TO
SUPPORT A MODERATELY UNSTABLE AIR MASS BY AFTERNOON WITH MLCAPES
APPROACHING 2000-3000 J/KG. OVER THE HIGH PLAINS...BOUNDARY LAYER
WILL BE SOMEWHAT DRIER...BUT RELATIVELY STEEP MIDLEVEL LAPSE RATES
WILL YIELD MLCAPES OF 1000-2000 J/KG.
SUSTAINED CONVERGENCE ALONG THE FRONT SHOULD SERVE TO FOCUS DIURNAL
STORM DEVELOPMENT WITHIN A KINEMATIC ENVIRONMENT CHARACTERIZED BY
RATHER WEAK VERTICAL SHEAR. NONETHELESS...THE MORE INTENSE STORMS
WILL BE CAPABLE OF LOCALLY STRONG WIND GUSTS AND MARGINALLY SEVERE
HAIL. THE HAIL POTENTIAL WILL BE GREATEST OVER THE HIGH PLAINS
OWING TO THE STEEPER LAPSE RATE ENVIRONMENT.
...MT...
A STRONG COLD FRONT WILL MOVE EWD THROUGH THE NRN INTERMOUNTAIN
REGION AND ADJACENT HIGH PLAINS IN ADVANCE OF AMPLIFYING UPPER
TROUGH TO THE W. PRE-FRONTAL AIR MASS IS FORECAST TO REMAIN RATHER
DRY WITH PW VALUES OF GENERALLY LESS THAN 0.6-0.7 INCH.
HOWEVER...LAPSE RATES WILL BE STEEP...RESULTING IN POCKETS OF WEAK
CONVECTIVE INSTABILITY. AS SUCH...THE POTENTIAL WILL EXIST FOR
ISOLATED STORMS ALONG OR IN IMMEDIATE POST-FRONTAL AIR MASS DURING
THE LATE AFTERNOON AND EVENING HOURS. SOME HAIL AND/OR STRONG WIND
GUSTS WILL BE POSSIBLE WITH THE MORE INTENSE STORMS GIVEN THE STEEP
LAPSE RATES...COOL THERMODYNAMIC PROFILES AND MODERATELY STRONG
VERTICAL SHEAR.
...LOWER CO VALLEY...
A MOIST...UNSTABLE AIR MASS IS FORECAST ACROSS THE REGION SATURDAY
ALONG NRN EXTENSION OF MONSOONAL MOISTURE SURGE. WHILE MIDLEVEL
WIND FIELDS ARE EXPECTED TO BE WEAKER THAN THE PREVIOUS COUPLE OF
DAYS...ENVIRONMENT WILL STILL BE SUPPORTIVE OF A FEW MORE INTENSE
STORMS CAPABLE OF MAINLY LOCALLY DAMAGING WIND GUSTS.
..MEAD.. 08/29/2008
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