Tuesday, August 31, 2010

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 311232
SWODY1
SPC AC 311230

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0730 AM CDT TUE AUG 31 2010

VALID 311300Z - 011200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE CNTRL PLNS TO
THE UPR MS VLY...

...SYNOPSIS...
AS LEAD SHORTWAVE IMPULSE ASSOCIATED WRN STATES TROUGH CONTINUES NE
INTO ONT THROUGH THE DAY...LARGER SCALE WRN STATES TROUGH WILL
DEAMPLIFY SOMEWHAT. THE NEXT DISTURBANCE IN THE TROUGH...NOW OVER
ERN ID/UT...SHOULD SHEAR NE ACROSS THE DAKOTAS/NRN MN LATER
TODAY/TONIGHT...BEFORE REACHING CNTRL ONT EARLY WED.

AT THE SFC...NRN PART OF COLD FRONT ATTENDANT TO LEAD SHORTWAVE
IMPULSE SHOULD MOVE STEADILY E/SE ACROSS THE UPR MS VLY/UPR GRT
LKS...WHILE THE SRN PART SETTLES MORE SLOWLY S ACROSS THE CNTRL
PLNS. THIS BOUNDARY WILL SERVE AS THE MAIN FOCUS FOR TSTMS THROUGH
THE PERIOD.

...CNTRL PLNS TO UPR MS VLY TODAY/TONIGHT...
PRE-FRONTAL ELEVATED TSTMS NOW PRESENT FROM NRN MO/IA NNE INTO
MN/WRN WI SHOULD MOVE/DEVELOP GENERALLY NEWD THROUGH EARLY
AFTN...WITH LITTLE CHANGE IN INTENSITY EXPECTED AS LEAD UPR IMPULSE
MOVES FARTHER NE INTO CANADA. CLOUDS AND OUTFLOW FROM THIS ACTIVITY
WILL SOMEWHAT DIMINISH LOW LVL DESTABILIZATION FARTHER W ALONG
AFOREMENTIONED COLD FRONT.

NEVERTHELESS...COMBINATION OF EVEN MODERATE SFC HEATING WITH ASCENT
PROVIDED BY GLANCING INFLUENCE OF UPSTREAM DISTURBANCE THAT WILL BE
CROSSING THE NRN PLNS SHOULD SUPPORT NEW STORM DEVELOPMENT ALONG THE
FRONT OVER FAR WRN WI...SRN MN...AND NRN IA BY MID AFTN. A BIT
LATER...DEVELOPMENT SHOULD OCCUR FARTHER SW ALONG THE BOUNDARY INTO
ERN NEB/NRN KS.

30-40 KT DEEP SWLY SHEAR ORIENTED ROUGHLY PARALLEL TO LOW LVL
FORCING...SBCAPE OF 2500-3000 J/KG...AND PW AOA 1.75 INCHES SHOULD
PROVE FAVORABLE FOR STRONG MULTICELL CLUSTERS...AND A FEW
SUPERCELLS...MAINLY DURING THE EARLIER STAGES OF DEVELOPMENT. DMGG
WIND SHOULD BE THE MAIN SVR THREAT. HOWEVER...A CONDITIONAL RISK
FOR HAIL AND TORNADOES COULD DEVELOP WITH ANY LONGER-LIVED STORMS
THAT AVOID EARLY MERGING... ESPECIALLY OVER THE WRN/CNTRL/NRN
IA...SE NEB...FAR NRN KS...AND NW MO.

THE STORMS COLLECTIVELY SHOULD GENERATE A FAIRLY EXTENSIVE COLD POOL
BY EARLY/MID EVE. THIS SHOULD FAVOR PROPAGATION OF STORMS AHEAD OF
THE FRONT...WITH A DIMINISHING THREAT FOR SVR AS THE ACTIVITY BUILDS
S/SE ACROSS KS...NRN MO AND NRN/WRN IL THROUGH EARLY WED.

...CNTRL HI PLNS LATE THIS AFTN INTO TONIGHT...
WEAK...INCREASINGLY MOIST POST-FRONTAL UPSLOPE FLOW MAY FOSTER THE
DEVELOPMENT OF SCTD TSTMS ALONG THE NRN CO FRONT RANGE AND/OR OVER
THE ADJACENT HI PLNS BY EARLY EVE. AS STORMS MOVE/DEVELOP EWD
ALONG/N OF THE STALLING FRONT...HIGHLY SHEARED/STEEP LAPSE RATE
ENVIRONMENT ON SRN FRINGE OF THE WLYS MAY YIELD A FEW STORMS CAPABLE
OF SVR HAIL/GUSTY WINDS. THESE MAY ORGANIZE INTO A SMALL CLUSTER OR
TWO THAT CONTINUES E INTO SRN NEB/NRN KS LATER TONIGHT.

...NRN ME TODAY...
SATELLITE SUGGESTS PRESENCE OF SEVERAL WEAK DISTURBANCES MOVING ESE
ACROSS S CNTRL QUEBEC. THESE FEATURES SHOULD CONTINUE ESE INTO NRN
NEW ENGLAND LATER TODAY WITHIN BAND OF MODEST WNWLY UPR LVL FLOW.
THEY MAY ENHANCE THE POTENTIAL FOR ISOLD AFTN TSTMS OVER NRN/ERN
ME...NOT FAR FROM STALLED FRONT IN NB. RELATIVELY WARM MID LVL
TEMPERATURES...AND WEAK FORCING FOR ASCENT/SHEAR ...SUGGEST THAT ANY
SVR THREAT WILL BE LIMITED.

..CORFIDI/ROGERS.. 08/31/2010

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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: