Severe Thunderstorm Warning 55, NWS Salt Lake City, UT

UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UTAH
300 AM MDT SAT SEP 11 1999

SYNOPSIS...A SOMEWHAT MOIST AND UNSTABLE AIRMASS OVER THE SOUTHERN
HALF OF UTAH WILL RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS
TODAY.  UP NORTH DRIER AND MUCH MORE STABLE AIR WILL FILTER IN FROM
THE NORTH.  THIS DRIER AND MORE STABLE AIR WILL SETTLE INTO
SOUTHERN UTAH SUNDAY.

DISCUSSION...SHOWERS AND ISOLD TSTRMS HAVE BROKEN OUT ALONG THE 700
MB CONFLUENCE ZONE SITUATED OVER CNTRL/SRN UTAH AT TIME.  THE AXIS
OF THE 250 MB JET THROUGH EXTREME SRN UTAH HAS HELP SUSTAIN STRONG
CONVECTION ACROSS EXTREME NW AZ/EXTREME SW UTAH.  ENTRANCE REGION OF
THIS JET SAG A BIT TO THE S AND E DURING THE DAY...WHICH SUGGEST
MOST ACTIVE CONVECTION MAY ALSO SHIFT WITH IT.  JET SUPPORT AND LOW
LEVEL FORCING BEGINS TO WANE LATE THIS AFTERNOON.  EXPECT THAT
THREAT FOR SHOWERS/TSTRMS SHOULD END AT LEAST IN THE CWA EARLY THIS
EVENING.

UP NORTH DRIER AIR AND LOW LEVEL COOL ADVECTION SHOULD PUT THE
SQUASH ON ANY SIGNIFICANT CONVECTION TODAY.  MAY SEE THE ODD
MOUNTAIN TSTRM...BUT BY AND LARGE A QUIET DAY IN STORE FOR AREAS
NORTH OF SLC.  DRIER..STABLE AIR SHOULD FILTER THROUGH MOST OF THE
CWA SUNDAY.

MEDIUM RANGE GUIDANCE A FAIRLY CLOSE AGREEMENT FOR THE COMING
WEEK. BOTH THE MRF AND ECMWF SHOW COOL CYCLONIC NORTHERLY FLOW
MONDAY YIELDING TO A STRONG UPPER RIDGE OVER THE WRN STATES BY
MIDWEEK.  COOL MORNING AND WARM AFTERNOON LOOK TO BE THE RULE FOR
THE EXTENDED FORECAST...AS IS TYPICAL FOR THE DRY PERIODS OF FALL
AROUND HERE.

SLC 110  CDC 432  CONGER

.SLC...NONE.