Severe Thunderstorm Warning 50, NWS Salt Lake City, UT

UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
415 AM MDT SUN SEP 8 2002

.SYNOPSIS...THE VERY MOIST AND SOMEWHAT UNSTABLE AIRMASS OVER
UTAH WILL REMAIN IN PLACE TODAY.  DRIER AIR WILL MOVE INTO THE
AREA MONDAY BEHIND A WEAKENING PACIFIC TROUGH THAT MOVES THROUGH
TONIGHT.

.DISCUSSION...UPPER LEVEL TROUGH THAT HAS BEEN TO OUR WEST FOR THE
PAST SEVERAL IN THE PROCESS OF LIFTING NE AND WEAKENING LATER
TODAY THROUGH TONIGHT.  VORTICITY MAX CURRENTLY OVER THE CNTRL
SIERRAS POSITIONED WELL BY THE 00Z MODEL RUNS.  THIS FEATURE WILL
LIFT NE WITH THE REMNANT OF THE TROUGH...CROSSING NW UT OVERNIGHT.

AXIS OF THE MOISTURE PLUME FROM NRN BAJA TO SRN CANADA REMAINS
SQUARELY OVER THE GREAT BASIN TODAY.  MOST AREAS OF UTAH HAVE SEEN
SIGNIFICANT RAINFALL THE PAST COUPLE OF DAYS....LEAVING THE
LOWER LEVELS COOLER AND MORE STABLE.  EXTENSIVE CLOUD COVER WILL
INHIBIT SURFACE HEATING...SO FOCUS OF CONVECTION WILL HAVE TO
AROUND THE BEST DYNAMICS.

JET AXIS ALONG THE UT/NV BORDER HAS BEEN THE FOCUS OF ACTIVE
CONVECTION SATURDAY AND THROUGHOUT THE NIGHT.  SEE NO REASON TO
CHANGE THIS THINKING TODAY.  APPROACHING VORTICITY MAX MENTIONED
ABOVE WILL BE A PLAYER BY LATER THIS AFTERNOON.  ADD TO THE
INCREASING VORTICITY ADVECTION THE MID-LEVEL COOL POOL MOVING
ACROSS NRN/WRN THIS EVENING AND WE COULD SEE CONVECTION HIT IT PEAK
LATE THIS AFTERNOON/EVENING.

S/CNTRL THROUGH ERN UT....WHILE SEEING A BIT LESS DYNAMIC SUPPORT...
SHOULD STILL SEE WIDESPREAD CONVECTIVE PRECIP TODAY.  WILL ISSUE A
CAVEAT TO LIMITED SURFACE HEATING FOR THIS AREA...THOUGH ANY BREAKS
WILL BE SHORT-LIVED AS CLOUDS/PRECIP QUICKLY FILL IN.  STRONG
CONVECTION EXPECTED TO BE LIMITED...THOUGH LOCALLY HEAVY
RAINFALL/SMALL HAIL NOT OUT OF THE QUESTION.  TOYED WITH THE IDEA
OF A FLASH FLOOD WATCH...BUT AGAIN SUSPECT THAT HEAVY RAIN THAT
DEVELOPS WILL BE RATHER ISOLATED AND BRIEF.

DRIER AIR WORKING IN BEHIND THE EJECTING/WEAKENING TROUGH CONFINED
TO THE NRN/WRN SECTIONS OF THE STATE.  WILL STILL SEE SCATTERED
CONVECTION SRN/ERN SECTION MONDAY...THOUGH CANT RULE OUT SOME
STORMS NRN/WRN SECTIONS AS LOW-LEVELS REMAIN MOIST.

HANG BACK LOW LEFT OVER FROM THE EJECTING TROUGH HANDLED A BIT
DIFFERENTLY BY THE 00Z ETA/AVN.  THE DIFFERENCE CENTERS AROUND
RETURN MOISTURE OUT OF AZ.   THE ETA MODEL FOR A CHANGE APPEARS TO
BRING FAR MORE MOISTURE BACK SOONER THAN THE AVN.  THIS SEEMS TO BE
A BIT TOO MUCH AS MUCH OF THIS ORIGINATES AROUND NRN BAJA WHICH
COULD DRY OUT HERE SHORTLY.  WILL FOLLOW THE AVN SOLUTION MORE
CLOSELY WHICH WOULD INDICATE A MORE LIMITED CONVECTION THROUGH THE
MIDDLE OF THE WEEK.  WEAK FLOW ALOFT AND RIDGING TO OUR WEST THE
END OF THE WEEK SUGGESTS SEASONAL TEMPS WITH GENERALLY DRY
CONDITIONS.

SLC 763  CDC 764  CONGER

.SLC...NONE.