Severe Thunderstorm Warning 47, NWS Salt Lake City, UT

UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
410 AM MDT SAT SEP 7 2002

.SYNOPSIS...A VERY MOIST AND SOMEWHAT UNSTABLE AIRMASS WILL REMAIN
THE GREAT BASIN THROUGH THE WEEKEND.  DRIER AIR WILL MOVE INTO
THE STATE FROM THE NORTHWEST LATE THIS WEEKEND.

.DISCUSSION...WELL DEFINED UPPER TROUGH OVER THE WEST COAST STATES
WILL ONLY MAKE SLOW EASTWARD PROGRESS TODAY.  THIS IN TURN WILL
MAINTAIN THE RATHER MOIST SSW FLOW INTO UTAH INTO AT LEAST EARLY
SUNDAY.

INGREDIENTS APPEAR TO BE IN PLACE FOR BOTH HEAVY RAIN AND AND AT
LEAST A FEW STRONG THUNDERSTORMS DURING THE DAY.  WITH TROPICAL
MOISTURE ALREADY IN PLACE...ANY LITTLE BIT OF DYNAMIC SUPPORT
SHOULD KICK OFF CONVECTION JUST ABOUT ANYWHERE IN THE STATE.
RIGHT-REAR QUADRANT OF THE 250 MB JET PROGGED TO REMAIN OVER WRN UT
TODAY.  DIVERGENCE ALOFT THAT RESULTS FROM THIS JET LOOKS FAIRLY
IMPRESSIVE.  THE SUBTROPICAL JET NOSING INTO NRN BAJA COULD LEAD TO
A COUPLED JET OVER WRN UT LATER TODAY...RIGHT IN AN AREA OF LOW-
LEVEL CONFLUENCE OVER SW THROUGH W/CNTRL UT.  SITUATION LOOKS GOOD
FOR STRONG CONVECTION WHICH COULD TRAIN OVER PORTIONS OF SRN/CNTRL
UT DURING THE DAY.  EVEN THOUGH THE MEAN FLOW IS FAIRLY STRONG...
YESTERDAYS STORMS WERE ABLE TO PRODUCE LOCALLY VERY HEAVY RAINFALL
AMOUNTS IN VERY SHORT PERIODS OF TIME.  WILL ISSUE A FLASH FLOOD
WATCH FOR MUCH OF THE SOUTH TO COVER THIS SITUATION TODAY.

CONVECTION WILL CONTINUE OVER MOST THE STATE TONIGHT AS THE
MOISTURE TAP REMAINS OPEN.  SUNDAY ALSO LOOKS INTERESTING AS THE
TROUGH LIFTS NE THROUGH THE STATE DURING THE DAY.  A LITTLE DRIER AIR
INTRUDING INTO WRN UT COULD LIMIT CONVECTION OVER THE FAR NW ZONES...
OTHERWISE WIDESPREAD CONVECTION A GOOD BET AGAIN SUNDAY.

A RELATIVELY WEAK FLOW ALOFT TRAILING THE EJECTING TROUGH EARLY NEXT
WEEK COULD EASILY LEAVE MOISTURE BACK OVER THE ERN/CNTRL PORTIONS OF
THE STATE.  WE COULD SEE SOME DIURNAL CONVECTIVE ACTIVITY BOTH
MONDAY AND TUESDAY.

THE LATEST MRF NOW LINING UP MUCH MORE LIKE THE UKMET FOR THE MIDDLE
TO LATTER HALF OF NEXT WEEK.  BOTH MODELS NOW DRAW THE NEWLY FORMED
PACIFIC TROUGH WELL BACK NEAR 150W...LEAVING THE WRN STATES IN WEAK
FLOW MEAN RIDGE POSITION.  FORECAST TREND IN GENERAL WOULD LOOK TO BE
A BIT DRIER/WARMER....THOUGH THE EUROPEAN MODELS DO HAVE A WRINKLE
WITH A WEAK UPPER LOW DRIFTING THROUGH THE REGION.  WOULDNT BE
SURPRISED IF ISOLATED CONVECTION WOULD FORM IN THIS SITUATION...BUT
NOT LOOKING FOR ANYTHING SIGNIFICANT FOR NOW.

SLC 765  CDC 766  CONGER

.SLC...FLASH FLOOD WATCH SOUTH CENTRAL THROUGH CENTRAL UT TODAY.