FXUS65 KSLC 151642
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
942 AM MST TUE DEC 15 2009
.SYNOPSIS...HIGH PRESSURE ALOFT WILL BE REPLACED BY A MOIST
WESTERLY FLOW ACROSS THE NORTHERN INTERMOUNTAIN REGION THROUGH
THURSDAY. A SERIES OF WEAK STORM SYSTEMS WILL GRAZE NORTHERN
UTAH...BRINGING LIGHT PRECIPITATION TO FAR NORTHERN UTAH INTO
THURSDAY.
&&
.DISCUSSION...THE LOW AMPLITUDE UPPER RIDGE ACROSS THE GREAT
BASIN WILL YIELD TO A MOIST WESTERLY FLOW ALOFT THROUGH THE
MIDWEEK PERIOD. EMBEDDED WEAK SHORTWAVES WILL FOCUS ON THE NRN
ROCKIES/NRN GREAT BASIN INTO THURSDAY. WEAK DYNAMIC LIFT AND
MINIMAL THERMAL ADVECTION WILL KEEP PRECIP GENERALLY ON THE
LIGHT SIDE...WITH MOST OF THE ACTIVITY CONFINED TO THE MOUNTAIN
LOCATIONS. THE COLDER NRN VALLEYS COULD SEE A SHALLOW PROLONGED
OVERRUNNING EVENT DEVELOP...WITH THE CACHE...BEAR RIVER AND OGDEN
VALLEYS SEEING A DECENT SNOW EVENT THROUGH MIDWEEK. SRN/CNTRL UTAH
WILL LIKELY SEE SOME CLOUDS...BUT WILL BE SUFFICIENTLY FAR REMOVED
FROM ANY REAL THREAT OF PRECIP THROUGH THE BALANCE OF THE WEEK.
GENERALLY AGREEMENT BETWEEN THE ECMWF/CANADIAN/GFS ON BRINGING A
SOLID UPPER RIDGE INTO THE REGION THURSDAY NIGHT/FRIDAY. THE ECMWF
AND CANADIAN MAINTAIN THE RIDGE OVER THE WRN STATES THROUGH THE COMING
WEEKEND. THE GFS IN CONTRAST BRING A SHORTWAVE THROUGH THE RIDGE...
AND DRIVES IT SE ACROSS WY/NRN UTAH LATE SATURDAY THROUGH EARLY SUNDAY.
RECENT TRENDS IN THE GFS HAVE BEEN TO SHADE TOWARDS THE ECMWF SOLUTION
AS THE EVENT GETS CLOSER. SUSPECT THIS WILL BE THE CASE THIS TIME.
CURRENT FORECAST NARRATIVE WRITTEN TOWARD THE ECMWF SOLUTION...WITH
NO PLANS TO CHANGE THIS AT THIS TIME.
NO UPDATE THIS MORNING.
&&
.AVIATION...THE SLC TERMINAL WILL SEE VFR CONDITIONS WITH
INCREASING CLOUDS DURING THE LATE MORNING/AFTERNOON HOURS. WINDS
ARE EXPECTED TO REMAIN SOUTHERLY DURING THE DAY...BUT THERE IS A
30 PERCENT CHANCE OF A SHIFT TO THE NORTHWEST BETWEEN 20Z AND 22Z.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...NONE.
&&
$$
PUBLIC...CONGER
AVIATION...TRAPHAGAN
FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)
