FXUS65 KSLC 022227
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
327 PM MST WED DEC 2 2009

.SYNOPSIS...A COLD AND GENERALLY DRY NORTHERLY FLOW ALOFT WILL
REMAIN ACROSS UTAH THROUGH THURSDAY NIGHT. THE NEXT PACIFIC STORM
SYSTEM WILL MOVE SOUTH FROM WESTERN CANADA FRIDAY...AND SETTLE
INTO NORTHERN UTAH THIS WEEKEND.

&&

.DISCUSSION...THE FORECAST AREA REMAINS UNDER AN UNSEASONABLY COOL
NORTHERLY FLOW THIS AFTERNOON BETWEEN A DEVELOPING RIDGE OFF THE
CALIFORNIA COAST AND A BROAD STORM SYSTEM MOVING ACROSS THE
CENTRAL UNITED STATES. BECAUSE OF THAT...TEMPERATURES HAVE BEEN
STRUGGLING TO WARM TODAY...ESPECIALLY OVER NORTHERN UTAH...WHERE
MAXES SHOULD BE OVER 5F BELOW NORMAL. 

WITH THE AIRMASS REMAINING DRY AND STABLE...HAVE LOWERED TEMPS
FROM THE PREVIOUS PACKAGE FOR TONIGHT AND TOMORROW. THIS MEANS
THAT MAXES TOMORROW ARE PROGGED TO RUN 5-7F COOLER THAN TODAY. THAT
MEANS THAT TEMPERATURES ALONG THE WASATCH FRONT COULD STAY BELOW
FREEZING THROUGHOUT THE DAY. MODELS AGREE THAT THE FLOW ALOFT WILL
BECOME MORE WESTERLY BY FRIDAY AFTERNOON AS A PACIFIC STORM SYSTEM
APPROACHES. THIS WOULD ALLOW THE AIRMASS TO WARM BY ALMOST 10C AT
700 MB BETWEEN NOW AND FRIDAY...BUT SURFACE RIDGING IN PLACE WOULD
CONTINUE TO LIMIT MIXING. STILL...THE FORECAST AREA SHOULD SEE A
WARMING TREND IN TEMPERATURES...THOUGH THE CURRENT FORECAST COULD
BE A BIT OPTIMISTIC. 

GLOBAL MODELS CONTINUE TO OFFER DIVERGING SOLUTIONS FOR THE
WEEKEND AND BEYOND. ALL BRING THE PACIFIC TROUGH OVER NORTHERN
UTAH BEGINNING SATURDAY...BUT THE ASSOCIATED COLD FRONT IS MUCH
MORE WELL DEFINED IN 12Z GEM/EC SOLUTION...WHICH WOULD BRING A
GOOD BAND OF SNOW THROUGH NORTHERN AND CENTRAL UTAH...THOUGH THE
PRECIP WOULD BE FAST MOVING. 12Z GFS HAD A MORE ILL-DEFINED FRONT
AND LITTLE ASSOCIATED QPF...THOUGH THE FRONT IS BETTER DEFINED IN
THE 18Z RUN. POP GRIDS FAVOR THE EC/GEM SOLUTION OVER THE WEEKEND. 

THE BEGINNING OF NEXT WEEK LOOKS TO BE WET IN ALL MODELS...THOUGH
THE SOLUTIONS REMAIN QUITE A BIT DIFFERENT. GFS BRINGS A SECOND
TROUGH THROUGH THE STATE BEGINNING MONDAY NIGHT...AND IN IT
SOLUTIONS THIS FEATURE BRINGS A GOOD DEAL OF PRECIP TO MOSTLY
SOUTHERN UTAH THROUGH TUESDAY...BEFORE WEAK RIDGING AND A DRIER
AIRMASS MOVE IN. GEM LOOKS MORE SIMILAR TO THE GFS DURING THIS
PERIOD. ON THE OTHER HAND...THE ECMWF WEAKENS THE SECOND SYSTEM SO
THAT A SECOND WELL DEFINED TROUGH NEVER MOVES INTO THE AREA.
HOWEVER...WITH STRONG JET SUPPORT...PLENTY OF MOISTURE...AND ZONAL
FLOW...IT KEEPS PRECIP GOING OVER THE ENTIRE AREA THROUGH AT LEAST
MIDWEEK. IT SHOULD BE NOTED THAT THE EC SOLUTION IS MUCH WARMER
THAN THE GFS...AND PRECIPITATION MAY FALL AS RAIN IN THE VALLEYS
IF ITS SOLUTION PANS OUT. WITH ALL MODELS SHOWING A MOIST PATTERN
FOR THE BEGINNING OF NEXT WEEK...HAVE GONE QUITE A BIT ABOVE CLIMO
WITH THE POPS IN THE EXTENDED. 

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL AT THE KSLC TERMINAL THROUGH 
THE TAF PERIOD.  NORTH WINDS WILL CONTINUE THROUGH THE EVENING PUSH. 
THE TYPICAL SWITCH TO SOUTHEAST WINDS THIS EVENING WILL BE DELAYED 
UNTIL 0500-0700 UTC.  HOWEVER...THERE IS A 30 PERCENT CHANCE THAT 
THE WINDS WILL NOT SWITCH TO THE SOUTHEAST UNTIL AFTER 0700 UTC. 

&&

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

&&

$$

PUBLIC...TRAPHAGAN
AVIATION...GRAHAM

FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)