Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 192224
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
324 PM MST WED NOV 19 2014

.SYNOPSIS...HIGH PRESSURE WILL EXIT THE FORECAST AREA THIS
EVENING. A SERIES OF WEAKENING WEATHER SYSTEMS WILL CROSS THE
REGION TONIGHT THROUGH FRIDAY. A POTENT STORM SYSTEM IS EXPECTED
TO IMPACT MUCH OF THE FORECAST AREA THIS WEEKEND AND INTO EARLY
NEXT WEEK.

&&

.SHORT TERM (THROUGH 12Z SATURDAY)...HIGH PRESSURE OVER THE
FORECAST AREA IS SHIFTING EAST THIS AFTERNOON AHEAD OF AN
APPROACHING SHORTWAVE. BETTER MIXING AHEAD OF THE SYSTEM HAS
ALLOWED TEMPERATURES TO RUN A BIT ABOVE YESTERDAYS VALUES...NEAR
OR JUST SLIGHTLY BELOW SEASONAL NORMALS AS HIGH CLOUDS INCREASE.

THE WAVE IS PROGGED TO CROSS UTAH AND SOUTHWEST WYOMING TONIGHT
THROUGH THURSDAY. THIS FEATURE IS FAIRLY ILL-DEFINED AND LACKING
IN MOISTURE...SO ASSOCIATED PRECIPITATION WILL BE LIMITED AT BEST
AND CONFINED TO NORTHERN UTAH. THOUGH THE WAVE WILL BRING A BIT OF
COOLING ALOFT...BETTER MIXING SHOULD KEEP MAXES SIMILAR TO VALUES
OBSERVED TODAY.

THE FORECAST AREA SHOULD SEE VERY BRIEF RIDGING THURSDAY NIGHT.
HOWEVER...THE NEXT PACIFIC SYSTEM WILL BE APPROACHING DURING THAT
TIME. THE SYSTEM IS EXPECTED TO DIVE SOUTHWARD...MOVING ACROSS
ARIZONA ON FRIDAY BEFORE SLIDING INTO MEXICO AND TEXAS. THOUGH THE
BEST MOISTURE AND DYNAMICS WILL STAY WELL SOUTH OF THE CWA...A FEW
SHOWERS ARE POSSIBLE FOR SOUTHERN UTAH...WITH THE BEST CHANCE
OCCURRING ON FRIDAY MORNING.

&&

.LONG TERM (AFTER 12Z SATURDAY)...A STRONG UPPER JET PUNCHING INTO
THE GREAT BASIN SATURDAY MORNING WILL SIGNAL THE BEGINNING OF A
MULTI-DAY STORM PATTERN AND WHAT WILL BE A WET WEEKEND AHEAD FOR THE
FORECAST AREA. WITH DEEP MOISTURE ARRIVING AHEAD OF THE JET AND WARM
ADVECTION STRENGTHENING SATURDAY MORNING...EXPECT PRECIPITATION TO
FILL IN RAPIDLY OVER THE NORTHERN HALF OF THE FORECAST AREA. WINDS
WILL INCREASE DURING THIS TIME WHICH SHOULD PROVIDE SUFFICIENT
MIXING TO WARM THE LOW LEVELS AND KEEP SNOW LEVELS ABOVE THE VALLEY
FLOORS.

THE ASSOCIATED COLD FRONT WILL CROSS THE AREA DURING THE
AFTERNOON...WITH SNOW LEVELS GRADUALLY LOWERING BEHIND IT AND
PRECIPITATION SPREADING FARTHER INTO SOUTHERN UTAH. THE MOIST
NORTHWEST FLOW TO FOLLOW FOR THE NIGHTTIME HOURS WILL BE QUITE
FAVORABLE FOR PRECIPITATION ACROSS THE SPINE OF UTAH AND ADJACENT
VALLEY LOCALES. SNOW LEVELS SHOULD REACH THE VALLEY FLOORS AFTER
MIDNIGHT ACROSS MOST OF NORTHERN AND WESTERN UTAH.

ANOTHER IMPULSE EMBEDDED IN THE TRAILING EDGE OF THE MEAN TROUGH
LOOKS TO BRING A RENEWED BURST OF PRECIPITATION FOR SUNDAY MORNING.
AFTER THAT...WILL SEE A GENERAL DECREASE IN AREAL COVERAGE OF
PRECIPITATION SUNDAY AFTERNOON AND EVENING AS THE TROUGH BEGINS TO
EXIT THE AREA. HOWEVER...FAVORED NORTHWEST-FACING SLOPES WILL
CONTINUE TO DO WELL IN THIS PATTERN AND STORM TOTALS SATURDAY
THROUGH SUNDAY COULD BE QUITE SIGNIFICANT AS A RESULT.
ADDITIONALLY...SHOWERS DEVELOPING OFF THE GREAT SALT LAKE COULD ALSO
COME INTO PLAY FOR THE SALT LAKE VALLEY AND IMMEDIATELY ADJACENT
AREAS.

ANOTHER WEAK TROUGH EMBEDDED IN THE MEAN FLOW LOOKS TO ARRIVE MONDAY
MORNING. HOWEVER...THE GFS IS A BIT STRONGER WITH THIS FEATURE THAN
THE EC. EVEN WITH THE MODEL DIFFERENCES...THE PATTERN STILL LOOKS TO
REMAIN UNSETTLED THROUGH MONDAY. AFTER THAT...GREATER UNCERTAINTY
EXISTS AS GLOBAL MODELS DIFFER BETWEEN HOW STRONGLY THE RIDGE WILL
AMPLIFY. THE GFS DEVELOPS MORE OF AN ANTICYCLONIC FLOW WITH NET
RESULT BEING DRIER AND MORE STABLE CONDITIONS...BUT THE EC MAINTAINS
THE JET CLOSER TO THE AREA WHICH WILL KEEP THE AIRMASS A BIT MORE
MOIST WITH THE POTENTIAL FOR A FEW SHOWERS ACROSS THE NORTH.

&&

.AVIATION...NO OPERATIONAL WEATHER CONCERNS AT THE SLC TERMINAL
THROUGH THE TAF PERIOD UNDER VFR CONDITIONS. WIND WILL REMAIN
LIGHT...BUT A SHIFT TO THE SOUTH IS EXPECTED BETWEEN 02 AND 04Z.

&&

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

$$

SHORT TERM...TRAPHAGAN
LONG TERM/AVIATION...CHENG

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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