SWODY1
SPC AC 010536
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1236 AM CDT SAT SEP 01 2007
VALID 011200Z - 021200Z
..NO SVR TSTM AREAS FORECAST...
..SYNOPSIS...
SYNOPTIC PATTERN ALOFT WILL FEATURE STRONG RIDGING FROM 4-CORNERS
AREA HIGH NEWD ACROSS UPPER MS VALLEY AND UPPER GREAT LAKES...WITH
ANOTHER RIDGE NWD ACROSS NRN ROCKIES. SHORTWAVE TROUGH -- NOW
EVIDENT IN MOISTURE CHANNEL IMAGERY INVOF WRN ID BORDER...IS FCST TO
EJECT NEWD ACROSS NRN ROCKIES BY START OF PERIOD...THEN EWD THROUGH
LARGER SCALE RIDGE AND ACROSS SASK/MB. ASSOCIATED COLD FRONT WILL
MOVE ESEWD ACROSS DAKOTAS AND SSEWD ACROSS ERN WY AND NWRN NEB. BY
2/12Z...FRONT SHOULD LIE NEAR LINE FROM INL-MHE-CDR.
ELSEWHERE...NUMEROUS SMALL MID/UPPER LEVEL VORTICITY MAXIMA AND
CYCLONIC SHEAR ZONES...SOME OF WHICH WILL HAVE SFC
COUNTERPARTS...WILL PERSIST ACROSS MOST OF GULF COAST REGION IN
SUPPORT OF GEN THUNDER POTENTIAL.
..NRN PLAINS/UPPER MIDWEST...
VERY CONDITIONAL SVR POTENTIAL EVIDENT DURING LATE AFTERNOON INVOF
FRONT...SHIFTING OR REDEVELOPING FARTHER E OVER NRN MN DURING
OVERNIGHT HOURS NEAR MOISTENING/SWLY LLJ. ANY TSTMS THAT DO DEVELOP
DURING AFTERNOON INVOF FRONT MAY PRODUCE HAIL AND STG-SVR
GUSTS...WITH HAIL ALSO POSSIBLE FROM ANY CLUSTERED/OVERNIGHT
ACTIVITY FARTHER E.
FAVORABLE FACTORS FOR CONVECTIVE DEVELOPMENT WILL INCLUDE
INCREASING/PREFRONTAL BOUNDARY LAYER MOISTURE...STG SFC
HEATING...AND SOME LIFT ALONG FRONT. FRONTAL CONVERGENCE WILL BE
LIMITED BY PRESENCE OF SWLY FLOW IN WARM SECTOR...WITH STRONGEST
ISALLOBARIC FORCING REMAINING OVER CANADA. MOIST ADVECTION AND
EVAPOTRANSPIRATION WILL CONTRIBUTE TO SFC DEW POINTS COMMONLY
MID-UPPER 60S F. THIS WILL COMBINE WITH STG SFC HEATING AND STEEP
MIDLEVEL LAPSE RATES TO SUPPORT MLCAPES AROUND 2000 J/KG ACROSS
CENTRAL/ERN DAKOTAS. THOSE LARGE LAPSE RATES WILL BE ASSOCIATED
WITH STRONG ELEVATED MIXED LAYER THAT WILL BE ROOTED IN SUBSTANTIAL
CAP. UPSTREAM SOUNDINGS...UPPER AIR ANALYSES AND MODEL FCST
SOUNDINGS INDICATE STRONG CAPPING WILL PERSIST FOR MUCH OF
AFTERNOON...AND MAY PREVENT DEVELOPMENT ALTOGETHER S OF CANADIAN
BORDER. ALTHOUGH SFC FLOW WILL BE SWLY...ENOUGH VEERING WITH HEIGHT
IS EXPECTED TO YIELD CURVED LOW LEVEL HODOGRAPHS. DEEP-LAYER BULK
SHEAR SHOULD BE MRGL -- WITH EFFECTIVE SHEARS PROGGED TO REMAIN AOB
40 KT MOST AREAS.
..AZ...
WIDELY SCATTERED TO SCATTERED TSTMS ARE FCST TO DEVELOP PRINCIPALLY
DURING MID-LATE AFTERNOON AND OVER HIGHER TERRAIN OF CENTRAL/ERN AZ.
THIS ACTIVITY WILL BE EMBEDDED WITHIN DEEP BUT NOT PARTICULARLY
STRONG LAYER OF ELY/NELY WINDS ALOFT...AROUND SRN PORTION OF
ANTICYCLONE. ACTIVITY SHOULD MOVE WWD/SWWD ACROSS DESERTS/VALLEYS
DURING LATE AFTERNOON...ATOP DEEP/WELL-MIXED BOUNDARY LAYERS
SUITABLE FOR MAINTAINING STG/POTENTIALLY DAMAGING GUSTS TO SFC.
CONVECTION SHOULD DIMINISH MARKEDLY AFTER APPROXIMATELY 03Z...WHEN
COMBINATION OF OUTFLOWS AND DIABATIC COOLING SUBSTANTIALLY
STABILIZES AIR MASS.
.EDWARDS/DARROW.. 09/01/2007
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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