Office: SLC

FXUS65 KSLC 232157
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
355 PM MDT TUE SEP 23 2008

.SYNOPSIS...HIGH PRESSURE ALOFT CENTERED OVER THE SOUTHERN ROCKIES
WILL GRADUALLY STRENGTHEN THROUGH THE COMING WEEKEND. MOISTURE WILL
RETURN FROM THE SOUTH LATE IN THE WEEK...AND REMAIN OVER THE AREA
THROUGH THE WEEKEND.

&&

.DISCUSSION...STABLE WESTERLY FLOW ALOFT ACROSS THE GREAT BASIN WILL
BACK HIGH PRESSURE STRENGTHENS ACROSS THE SRN ROCKIES THROUGH THE
COMING WEEKEND. THE INCREASINGLY WARM SOUTHERLY FLOW ALOFT BEGINNING
WEDNESDAY WILL CREATE SIGNIFICANTLY WARMER TEMPERATURES ACROSS THE
WRN VALLEYS WEDNESDAY/THURSDAY. MOISTURE STILL WELL TO THE SOUTH
OVER SRN AZ/NRN MEXICO WILL WORK BACK TO THE NORTH LATE IN THE
WEEK...BRINGING THE FIRST THREAT OF SPOTTY CONVECTION TO THE SRN
MOUNTAINS LATE IN THE WEEK.

THE CONVECTIVE THREAT LOOKS LIKE IT WILL INCREASE THIS WEEKEND...AND
CONTINUE INTO EARLY NEXT WEEK. THE PERSIST S-SW FLOW INTO THE BASIN
WILL CONTINUE TO BRING MOISTURE NORTH ACROSS ALL OF UTAH EARLY THIS
WEEKEND. THE WILD CARD IN THIS SITUATION WILL BE THE EXISTENCE OF AN
UPPER LOW OFF THE CA COAST BY THE LATTER HALF OF THE WEEKEND. BOTH
THE GFS AND ECMWF HAVE THIS FEATURE...WITH THE GFS BRINING IT IN A
BIT SOONER. WEAK SHORTWAVES EJECTING NORTH OUT OF THIS FEATURE WOULD
SUPPLY THE DYNAMIC LIFT TO GET CONVECTION ORGANIZED SATURDAY...WITH
INCREASED ACTIVITY AS THE REMNANT OF THE COASTAL LOW LIFTS THROUGH
LATE SUNDAY/MONDAY. THE BIG DIFFERENCE BETWEEN THE TWO MODELS WILL
BE TIMING AS THE ECMWF HAS A SIMILAR EVOLUTION...JUST SLOWER TIMING
WITH THE REMNANT MOVING THROUGH LATER ON MONDAY.

WILL PROBABLY SEE SOME TERRAIN- TIED CONVECTION AGAIN TUESDAY AS THE
MOISTURE WILL BE SLOW TO LEAVE THE AREA UNDER A LIGHT MEAN FLOW
ALOFT. THE WESTERLIES LOOK LIKE THEY WILL PUNCH INTO THE WRN CONUS
AGAIN THE MIDDLE OF NEXT WEEK...THOUGH THE ECMWF KEEP THE CORE OF
THE WESTERLIES FURTHER NORTH THAN THE GFS.

&&

.AVIATION...LIGHT AND VARIABLE WINDS...WITH A MAINLY NORTHERLY
COMPONENT WILL CONTINUE AT THE SLC TERMINAL THROUGHOUT THE AFTERNOON
AND INTO THE EVENING. WINDS ARE EXPECTED TO SHIFT TO THE SOUTHEAST
BETWEEN 02-04Z TONIGHT.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...NONE.

&&

$$

CONGER/KRUSE

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