Friday, October 12, 2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 121246
SWODY1
SPC AC 121243

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0743 AM CDT FRI OCT 12 2007

VALID 121300Z - 131200Z

..NO SVR TSTM AREAS FORECAST...

..SYNOPSIS...
FAIRLY POTENT UPR LOW/TROUGH NOW OFF THE NRN CA CST SHOULD CONTINUE
E/SE TO NEAR SFO THIS EVENING BEFORE TURNING MORE E INTO THE SRN GRT
BASIN EARLY SATURDAY. AT THE SAME TIME...EXPECT DOWNSTREAM RIDGE TO
PERSIST ACROSS THE PLNS GIVEN SLOW DEAMPLIFICATION/EWD MOVEMENT OF
COMPLEX SYSTEM OVER THE GRT LKS/NORTHEAST.

AT THE SFC...A LEE LOW SHOULD CONSOLIDATE WITH TIME OVER THE SRN HI
PLNS AS HEIGHTS FALL OVER THE CNTRL/SRN RCKYS. PERSISTENT LOW LVL
RIDGING ACROSS THE NWRN GULF/LWR MS VLY...HOWEVER...WILL KEEP AXIS
OF BOUNDARY LYR MOISTURE RETURN COMPARATIVELY NARROW INVOF
STRENGTHENING LLJ OVER THE SRN/CNTRL PLNS.

..CNTRL PLNS...
SCTD ELEVATED STORMS SHOULD PERSIST THROUGH THE DAY IN AREA OF WAA
IN EXIT REGION OF LLJ OVER PARTS OF KS AND SRN NEB. ADDITIONAL BUT
MORE WIDELY SCTD DEVELOPMENT MAY ALSO OCCUR SWD ALONG ERN SIDE OF
LLJ INTO WRN OK/NW TX. DIURNAL HEATING AND CONTINUED MOISTURE
INFLUX IN UPSTREAM ENVIRONMENT MAY ENHANCE UPDRAFT STRENGTH THIS
AFTN/EVENING...AND YIELD A FEW STORMS WITH MARGINALLY SVR HAIL.
FARTHER SW...RELATIVELY WEAK LARGE SCALE ASCENT...ABSENCE OF SFC
FOCUSING MECHANISMS...AND LIMITED INSTABILITY SUGGEST THAT POTENTIAL
FOR SURFACE-BASED STORMS IN WARM SECTOR WILL BE LOW.

LATER TONIGHT AND EARLY SATURDAY EXPECT STORM COVERAGE WILL INCREASE
FROM CNTRL/NRN KS INTO WRN/SRN NEB AND PERHAPS SW SD AS LLJ
INTENSIFIES IN RESPONSE TO BOTH DIURNAL INFLUENCES AND CONTINUED EWD
MOVEMENT OF CA TROUGH. STEEPENING MID LVL LAPSE
RATES AND 30-40 KT CLOUD-LYR SHEAR COULD POSE A THREAT FOR
MARGINALLY SVR HAIL WITH SOME STORMS.

..SRN HI PLNS...
ISOLD LATE AFTN TSTMS MAY ONCE AGAIN FORM IN LOW LVL MOISTURE AXIS
FROM THE SW TX MOUNTAINS NNE INTO THE SRN HI PLNS. SUFFICIENT
INSTABILITY /SBCAPE TO 1000 J PER KG/ SHOULD DEVELOP TO SUPPORT
STRONG UPDRAFTS. BUT WEAKER UPSLOPE COMPONENT TO NEAR-SFC
WINDS...AND MORE ZONAL MID/UPR UPR FLOW...SUGGEST THAT COVERAGE OF
SUSTAINED ACTIVITY SHOULD BE REDUCED RELATIVE TO YESTERDAY. THE
GREATEST POTENTIAL FOR STRONG STORMS/POSSIBLE SHORT-LIVED
SUPERCELLS...SHOULD EXIST OVER W TX...WHERE A FEW HAIL REPORTS MAY
OCCUR.

.CORFIDI/GRAMS.. 10/12/2007

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