Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 201652
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
952 AM MST THU NOV 20 2014

.SYNOPSIS...A VERY WEAK PACIFIC TROUGH IS MOVING THROUGH NORTHERN
UTAH TODAY. ANOTHER WEAK SYSTEM WILL BRUSH SOUTHWEST UTAH EARLY
FRIDAY. A MUCH STRONGER STORM SYSTEM WILL MOVE INTO THE AREA
SATURDAY AND CONTINUE THROUGH MONDAY.

&&

.DISCUSSION...REMNANTS OF PACIFIC TROUGH ARE MOVING THROUGH
NORTHERN UTAH TODAY. RADAR SHOWS CONSIDERABLE VIRGA...BUT LITTLE
IF ANY PRECIP REACHING THE GROUND. EXPECT A FEW MOUNTAIN SNOW
SHOWERS AND PERHAPS A SPRINKLE OR TWO THIS AFTERNOON IN THE
VALLEYS MAINLY OGDEN NORTHWARD.

NEXT TROUGH NOW ENTERING CA IS A BIT STRONGER BUT ALL MODELS SHOW
IT CLOSING OFF AND GOING SOUTH THROUGH LAS VEGAS AND INTO AZ LATE
TONIGHT AND EARLY FRIDAY. 12Z GFS/NAM BOTH INDICATE SOME LIGHT
PRECIP OVER SOUTHWEST CORNER OF UTAH FRIDAY MORNING WHILE 00Z EC
INDICATES NO PRECIP IN UTAH WITH THIS TROUGH. CURRENT POPS IN
CHANCE CATEGORY SEEM APPROPRIATE.

OVERNIGHT MODELS AND QUICK LOOK AT 12Z GFS INDICATE LITTLE CHANGE
FOR WEEKEND STORM SYSTEM. NEW 12Z GFS IS JUST A TAD LESS COLD AT
500 MB WITH SATURDAY NIGHT AND SUNDAY NIGHT TROUGHS...BUT
TIME/HEIGHT SECTIONS FOR SLC SHOW DEEP INSTABILITY THROUGH 450 MB.
LATEST 12Z GFS ALSO CONTINUES TO GENERATE PRECIP MONDAY AND MONDAY
NIGHT AS WARM FRONT MOVES OVER AREA AT TAIL END OF STORM WHILE
PREVIOUS GFS HAD THIS MOISTURE FURTHER NORTH. STILL LOOKS LIKE AN
EXCELLENT SET UP FOR OROGRAPHIC SNOW FOR NORTHERN MOUNTAINS FROM
SATURDAY AFTERNOON THROUGH MONDAY...AND POSSIBLY INTO TUESDAY
MORNING WITH AREAS THAT ARE FAVORED BY NORTHWEST FLOW DOING
PARTICULARLY WELL IN THIS PATTERN. WINTER STORM WATCH FOR NORTHERN
MOUNTAINS STILL LOOKS ON TRACK.

VALLEY SNOW FORECAST IS TOUGHER. PRECIP SHOULD CHANGE TO SNOW
SHORTLY AFTER FROPA SATURDAY AFTERNOON IN THE NORTH...EAST BENCH
AREAS MAY DO QUITE A BIT BETTER THAN VALLEY FLOORS OR WEST SIDE OF
SALT LAKE AND UTAH COUNTY. STILL A FEW DAYS OUT SO LOTS OF
UNCERTAINTY ABOUT VALLEY SNOW AMOUNTS. LAKE EFFECT IS WILDCARD.
LOOKING AT ALCOTT`S STUDY SUGGESTS ONLY ABOUT A 10-20 PERCENT
CHANCE OF DREADED LAKE EFFECT AS 700 MB TEMPS ARE NOT ALL THAT
COLD. USED A LAKE TEMP OF PLUS 6 IN THE CALCULATION.

ONLY CHANGE TO CURRENT FORECAST AT THIS TIME WAS TO DIMINISH CLOUD
COVER OVER SOUTHWEST UTAH.

&&

.AVIATION...CIGS ARE EXPECTED TO REMAIN AT OR ABOVE 7K FT AGL
THROUGH 00Z BUT THERE IS A 40 PERCENT OF CIGS LOWERING BELOW 7K FT
AGL BETWEEN 19 AND 00Z. WINDS WILL BE LIGHT AND VARIABLE THROUGH
ABOUT 19Z THEN SHOULD SET UP WEAKLY OUT OF THE NORTHWEST.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WINTER STORM WATCH FROM LATE FRIDAY NIGHT THROUGH LATE MONDAY
     NIGHT FOR UTZ007>009.

WY...NONE.
&&

$$

PUBLIC...DUNN
AVIATION...WILENSKY

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

FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)


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