Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 241014
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
314 AM MST SAT JAN 24 2015

.SYNOPSIS...STRONG HIGH PRESSURE WILL BUILD INTO THE WESTERN
STATES THROUGH EARLY NEXT WEEK...BEFORE A WEAK STORM SYSTEM PASSES
THROUGH THE AREA MONDAY NIGHT INTO TUESDAY.

&&

.SHORT TERM (THROUGH 12Z TUESDAY)...
WATER VAPOR LOOP SHOWS AN EXPANSIVE EASTERN PACIFIC RIDGE
BUILDING INTO THE REGION AS A CLOSED LOW DEVELOPS OFF OF BAJA.
AMDAR 400- 250MB WIND OBSERVATIONS INDICATE A 75-175KT
ANTICYCLONIC JET FROM BRITISH COLUMBIA OVER THE NORTHERN ROCKIES
AND INTO SOUTHERN CALIFORNIA. GOES/GPS/RAP/00Z RAOB INDICATE THE
PRECIPITABLE WATER VALUE RANGES BETWEEN 0.05-0.15" MOUNTAINS...TO
0.25-0.30" MOST VALLEYS. BLENDED TOTAL PRECIPITABLE WATER PRODUCT
INDICATES VALUES MUCH BELOW NORMAL ACROSS THE SOUTHWEST...WITH A
MOISTURE TAP INTO THE PACIFIC NORTHWEST AND NORTHERN ROCKIES.

FAIRLY QUIET WEATHER DURING THE SHORT TERM PERIOD.

STRONG NORTHEASTERLY PRESSURE GRAIDENT IS SUPPORTING AN INCREASE IN
NORTHERLY GUSTS ACROSS PRONE DOWNSLOPE/CANYON AREAS OF SOUTHERN
UTAH...GENERALLY IN THE 25 TO 35 MPH RANGE. THESE WINDS GRADUALLY
DIMINISH THROUGH SUNDAY MORNING.

RIDGETOP TEMPERATURES CONTINUE THE WARMING TREND THROUGH MONDAY.
WITH RIDGING SURFACE AND ALOFT DOMINATING...EXPECT INVERTED
CONDITIONS TO INTENSIFY. NOT A LOT OF VALLEY SNOW COVER SO NO
SIGNIFICANT CHANGES TO VALLEY TEMPERATURE TRENDS. AIR QUALITY ON THE
OTHER HAND EXPECTED TO DETERIORATE THROUGH EARLY NEXT WEEK.
INTRODUCED HAZE INTO THE URBAN CORRIDOR MONDAY AFTERNOON.

THE AFORMENTIONED CLOSED LOW IS DEPICTED TO LIFT ALONG THE SOUTHERN
CALIFORNIA COAST INTO TUESDAY MORNING. TROPICAL MOISTURE LIFTS
NORTHWARD AS THE RIDGE DEPARTS TO THE EAST. EJECTING WEAKENING WAVES
WITHIN DIFFLUENT FLOW LIKELY TO SUPPORT SHOWER ACTIVITY DEVELOPING
ACROSS SOUTHERN UTAH MONDAY NIGHT. MANY LOCATIONS WOULD SEE
RAIN...WITH THE SNOW LEVEL EXPECTED TO RANGE BETWEEN 7-8KFT.

&&

.LONG TERM (AFTER 12Z TUESDAY)...
REMNANT ENERGY OF THE EARLY WEEK CLOSED OVER THE SOUTHEAST
PACIFIC REMAINS FORECAST TO MOVE INTO CENTRAL NEVADA TUESDAY.
ELEVATED PW VALUES WITHIN EXPANDING SOUTH TO SOUTHEAST FLOW WILL
CONTINUE TO SPREAD NORTH ACROSS THE FORECAST AREA THROUGHOUT THE
DAY REACHING MOST ALL AREAS BY MIDDAY...PW VALUES ON AVERAGE NEAR
.50 INCHES REMAIN PROGGED. THIS SAID...BUFR SOUNDINGS INDICATE A
RATHER STABLE LOW/MID PROFILE W/DRY LOW LEVELS AND PRIMARY FORCING
LOOKS TO FOCUS ABOUT THE REMNANT MID LEVEL CIRCULATION
TRANSITIONING INTO NEVADA. EXPECTING WIDESPREAD CLOUDS AND
GENERALLY LIGHT AND SHOWERY PRECIP TO TRANSITION NORTH W/THE
INFLUX OF MOISTURE AND WEAK MID LEVEL CAA/DIVERGENCE ALOFT BUT
PRECIP OF ANY SIGNIFICANCE SHOULD REMAIN TO OUR WEST. LOOKING LIKE
A FAIRLY HIGH POP AND LOW QPF SITUATION FOR OUR AREA TUESDAY ATTM.

AFOREMENTIONED CIRCULATION OVER NEVADA CONTINUES TO DISSOLVE AS THE
SHORT WAVE CONTINUES TO OPEN UP TUESDAY NIGHT...WITH DYNAMIC LIFT
MOST LIKELY FOCUSING ALONG THE RESIDUAL TROUGH AXIS WHICH AT THAT
TIME WILL BE MOVING EAST ACROSS NEVADA THEN PRIMARILY NORTHERN UTAH
BY DAYBREAK. MODELS DIVERGE IN DETAIL SLIGHTLY REGARDING EVOLUTION
OF THIS FEATURE BUT TRENDED TOWARDS ECMWF/GEM AND BUMPED POPS/QPF UP
ALONG THE WASATCH FRONT/MOUNTAINS WITH PASSAGE OF THIS AXIS LATE
TUESDAY NIGHT INTO WED MORNING. A GRADUAL TAPERING TREND IN POPS
FROM WEST TO EAST REMAINS FOR LATER WED AS REMNANT ENERGY
WILL CONTINUE A DOWNSTREAM TRANSITION.

DURING THE TUE/WED TIMEFRAME H7 TEMPS WILL BE FALLING SOME 10
DEGREES TO NEAR -5 C...THIS AIDING VENTILATION POTENTIAL FOR
LINGERING VALLEY/BASIN INVERSIONS. LIKELY SOME HELP FOR STAGNANT
CONDITIONS THAT WILL BE IN PLACE BUT A COMPLETE TURNOVER REMAINS
UNCERTAIN.

GLOBAL MODELS CONTINUE TO INDICATE A RETURN TO A STRONG BLOCKING
PATTERN ACROSS THE EASTERN PACIFIC THROUGH THE LATTER HALF OF THE
WEEK...WITH PACIFIC ENERGY FALLING INTO THE WEAKNESS WHERE THE
PREVIOUS LOW WAS POSITIONED...FORMING ANOTHER CLOSED LOW OVER THE
SOUTHEASTERN PACIFIC. WILL CONTINUE TO MONITOR FUTURE RUNS TO SEE IF
ANY NORTHERN BRANCH ENERGY ATTEMPTS TO CLIP THE NORTH...AND IF SAID
LOW GENERATES A NEW TAP W/THE ITCZ ONCE AGAIN.

&&

.AVIATION...OPERATIONAL WEATHER CONCERNS ARE EXPECTED TO REMAIN
MINIMAL AT THE KSLC TERMINAL THROUGH THE VALID TAF PERIOD. LIGHT
SOUTHEAST SURFACE WINDS ARE EXPECTED TO SWITCH TO THE NORTHWEST
BETWEEN 18-19Z PER NORM.

&&

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

$$

SHORT TERM...ROGOWSKI
LONG TERM/AVIATION...MERRILL

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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