SWODY3
SPC AC 280728
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0228 AM CDT SAT AUG 28 2010
VALID 301200Z - 311200Z
...THERE IS A SLGT RISK OF SVR TSTMS LATE MONDAY AFTERNOON AND
EVENING ACROSS PARTS OF THE NORTHERN PLAINS...
...SYNOPSIS...
MODELS INDICATE THAT A HIGH CENTER OVER THE MID ATLANTIC STATES WILL
REMAIN STRONG THROUGH THIS PERIOD...WITHIN BROADER SCALE SUBTROPICAL
RIDGING...WHICH APPEARS LIKELY TO EXPAND WEST NORTHWESTWARD ACROSS
THE NORTHERN MEXICAN PLATEAU AND PARTS OF THE SOUTHERN ROCKIES AND
PLATEAU REGION. THIS IS EXPECTED TO OCCUR AS LARGE SCALE TROUGHING
BEGINS TO LIFT OUT OF THE WESTERN STATES... GENERALLY COINCIDENT
WITH THE NORTHEASTWARD ACCELERATION OF A SIGNIFICANT EMBEDDED SHORT
WAVE TROUGH OUT OF THE GREAT BASIN THROUGH THE CENTRAL CANADIAN/U.S.
BORDER AREA BY EARLY TUESDAY.
GUIDANCE CONTINUES TO SUGGEST THAT THIS WILL BE ACCOMPANIED BY
FAIRLY STRONG SURFACE CYCLOGENESIS...WHICH COULD COMMENCE AS EARLY
AS MONDAY NIGHT...MAINLY OVER SOUTHEASTERN MANITOBA INTO
NORTHWESTERN ONTARIO. HOWEVER...SUBSTANTIAL SPREAD EXISTS AMONG THE
DATA CONCERNING THE EVOLUTION OF THIS PROCESS...INCLUDING THE TIMING
OF THE ARRIVAL OF STRONGER FORCING ASSOCIATED WITH THE UPPER IMPULSE
INTO THE NORTHERN U.S. PLAINS MONDAY/MONDAY NIGHT.
...NORTHERN PLAINS...
DESPITE THE LINGERING UNCERTAINTIES...THERMODYNAMIC PROFILES...
CHARACTERIZED BY A HOT AND DEEPLY MIXED BOUNDARY LAYER...STEEP
MID-LEVEL LAPSE RATES AND ENOUGH MOISTURE TO SUPPORT SUFFICIENT CAPE
FOR VIGOROUS CONVECTIVE DEVELOPMENT...ARE EXPECTED TO EVOLVE IN A
PRE-FRONTAL CORRIDOR FROM NORTH CENTRAL NEBRASKA THROUGH EASTERN
NORTH DAKOTA BY LATE MONDAY AFTERNOON. IT SEEMS PROBABLE THAT THIS
WILL OCCUR JUST PRIOR TO THE ARRIVAL OF STRONGER MID-LEVEL HEIGHT
FALLS AND LOWER/MID TROPOSPHERIC COOLING...WHICH SHOULD WEAKEN
LINGERING INHIBITION SUFFICIENTLY FOR THE INITIATION OF STORMS.
DEEP LAYER SHEAR WITHIN THIS ZONE MAY BE SOMEWHAT MODEST...BUT
30-40+ KT...AND STRENGTHENING...SOUTHWESTERLY LOWER/MID TROPOSPHERIC
FLOW IS EXPECTED TO AUGMENT A FAVORABLE ENVIRONMENT FOR STRONG
DOWNBURSTS AND SURFACE COLD POOL DEVELOPMENT...ACCOMPANIED BY
DAMAGING SURFACE WIND GUSTS. THIS THREAT IS EXPECTED TO PERSIST
WITH A GROWING EASTWARD ADVANCING LINE OR CLUSTER OF THUNDERSTORMS
AT LEAST INTO THE EVENING HOURS ...BEFORE PERHAPS WANING IN A LESS
STRONGLY HEATED/DEEPLY MIXED AND COOLING BOUNDARY LAYER TOWARD THE
UPPER MISSISSIPPI VALLEY.
..KERR.. 08/28/2010
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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