FXUS65 KSLC 012230
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
330 PM MST TUE DEC 1 2009

.SYNOPSIS...A COLD TROUGH OVER THE NORTHERN ROCKIES TODAY WILL
PUSH UNSEASONABLY COLD AIR INTO THE AREA TONIGHT AND WEDNESDAY.
THIS COLD AIRMASS WILL REMAIN OVER THE AREA INTO EARLY FRIDAY.

&&

.DISCUSSION...SHORT TERM...COLD AIR AT 700 MB AND BELOW NOW
BEGINNING TO PUSH SOUTH INTO THE AREA AND THIS COLD AIR ADVECTION
CONTINUES THROUGH EARLY THURSDAY BEFORE ABATING. SO BIG MESSAGE
THE NEXT FEW DAYS IS BRRRR. IT WILL BE MOSTLY SUNNY AFTER THE NEXT
FEW DAYS SO IT WILL LOOK THE SAME AS IT HAS BEEN...BUT TEMPS WILL
BE 15 TO 20 DEGREES COOLER THAN RECENT DAYS. 12Z AND 18Z NAM
CONTINUE TO SHOW NEARLY SATURATED CONDITIONS FROM THE SURFACE TO
11K MSL OVER THE WASATCH FRONT EASTWARD TO THE UINTAS LATER
TONIGHT SO FORECAST INCLUDES ABOUT A 20 PERCENT CHANCE OF LIGHT
SNOW BUT BEST THREAT FOR AN INCH WILL BE ALONG THE NORTH SLOPES OF
THE UINTAS WITH JUST A FEW FLAKES LIKELY ELSEWHERE.

LONGER TERM...ALL MODELS CONTINUE TO SHOW MAJOR PATTERN SHIFT WITH
RIDGE THAT HAS BEEN ALONG THE WEST COAST FOR ABOUT 5 WEEKS
REDEVELOPING WESTWARD AND NORTHWARD OVER ALASKA. ALL MODELS ALSO
DEVELOP A COLD TROUGH OVER THE PACIFIC NORTHWEST BY SATURDAY WITH
SURFACE COLD FRONT JUST NORTH OF UTAH BY SATURDAY AFTERNOON. AFTER
THAT THE MODELS BEGIN TO DIVERGE WITH THE GFS AND CANADIAN GEM
DEEPENING THE TROUGH INTO THE GREAT BASIN OVER THE WEEKEND WHILE
THE EC CONTINUES TO SHOW WESTERLIES BREAKING THROUGH UNDER THE
AFOREMENTIONED RIDGE WITH THE MILDER AND MORE MOIST WESTERLIES
BRINGING A LOT MORE PRECIP TO THE GREAT BASIN THAN THE COLDER AND
DEEPER GFS/GEM SOLUTION. LATEST 12Z EC HAS A WEAKER UNDERCUTTING
TROUGH IN THE WESTERLIES THAN PREVIOUS 00Z EC. OVERALL
PROBABILITY OF PRECIP FOR THE ENTIRE FORECAST AREA LOOKS TO BE
FAIRLY HIGH FROM SATURDAY NIGHT ON THROUGH THE EARLY PART OF NEXT
WEEK...BUT AMOUNTS AND SNOW LEVELS VARY DEPENDING ON THE MODEL.
HAVE INCREASED POPS TO ABOVE CLIMO LEVELS FOR THE PERIOD BUT
BELIEVE IT IS FAR TOO EARLY TO PUT MUCH DETAIL IN DAYS 5 THROUGH 7
GIVEN THE MODEL DIFFERENCES.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL AT SLC TERMINAL THROUGH THIS 
EVENING. CEILINGS COULD TEMPORARILY LOWER TO BELOW 6000 FT BETWEEN 
06Z AND 12Z TONIGHT...BUT THERE IS ONLY A 20 PERCENT CHANCE. NORTH 
TO SOUTH SURFACE GRADIENT WILL FAVOR NORTH WINDS TO CONTINUE THROUGH 
TONIGHT WITH A SLIGHT CHANCE OF BECOMING SOUTHEAST AFTER 12Z TONIGHT.

&&

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

&&

$$

PUBLIC...DUNN
AVIATION...STRUTHWOLF

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