Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 300427
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
927 PM MST THU JAN 29 2015

.SYNOPSIS...A DEVELOPING UPPER LOW OVER THE SOUTHERN GREAT BASIN
WILL SPREAD MOISTURE INTO UTAH TONIGHT THROUGH SATURDAY. THE
DEEPEST MOISTURE WILL REMAIN PRIMARILY OVER CENTRAL AND SOUTHERN
UTAH.

&&

.DISCUSSION...CURRENT LARGE-SCALE PATTERN AS INDICATED BY WATER
VAPOR IMAGERY INDICATES A STORM SYSTEM CENTERED OFF THE BAJA COAST
WHILE A COUPLE OF OTHER SMALLER BUT WELL-DEFINED LOWS ARE EVIDENT
OVER THE WEST COAST STATES. A WEAK SHORTWAVE DISTURBANCE IS
CURRENTLY EJECTING NORTH THROUGH UTAH WHICH HELPED SPREAD MOISTURE
INTO THE AREA IN THE FORM OF ABUNDANT MID/HIGH CLOUDS. WEAK WARM
ADVECTION BEHIND THIS WAVE ALLOWED SOME LIGHT PRECIPITATION TO
DEVELOP. THIS WAVE IS REACHING NORTHERN UTAH THIS EVENING...JUST
HAVING CROSSED A WENDOVER TO PROVO LINE. ALTHOUGH MEASURABLE
PRECIPITATION IS NOT VERY LIKELY ACROSS MUCH OF NORTHERN UTAH
TONIGHT...SPRINKLES AND HIGH-ELEVATION FLURRIES ARE POSSIBLE.

THE VARIOUS PIECES OF ENERGY MENTIONED ABOVE WILL EVENTUALLY WRAP
INTO A SINGLE LARGER LOW WHICH WILL TRACK INTO ARIZONA TOMORROW
EVENING BEFORE RETREATING SOUTH INTO MEXICO SATURDAY AFTERNOON.
FOLLOWING THE LIGHT PRECIPITATION WITH THE INITIAL WAVE REACHING
NORTHERN UTAH TONIGHT...PRECIPITATION WILL THEN BECOME LARGELY
CONFINED SOUTH OF A DEFORMATION AXIS THAT WILL SETTLE ACROSS CENTRAL
UTAH. HOWEVER...DEEP TROPICAL MOISTURE IS BEING TAPPED IN THE SOUTH
FLOW AHEAD OF THE STORM SO SIGNIFICANT PRECIPITATION CAN BE EXPECTED
WITHIN THIS AREA. THE DEEP MOISTURE WILL START POURING INTO SOUTHERN
UTAH TONIGHT SO EXPECT PRECIPITATION RATES TO PICK UP OVER SOUTHERN
UTAH AFTER MIDNIGHT AND OVER CENTRAL UTAH TOMORROW MORNING. THERE IS
STILL SOME UNCERTAINTY OVER THE NORTHERN EXTENT OF THE PRECIPITATION
SHIELD...BUT MOST LIKELY THIS WILL BE NEAR THE PROVO AREA.

RELATIVELY WARM AIRMASS ASSOCIATED WITH THIS STORM IS EXPECTED TO
KEEP SNOW LEVELS HIGH. MAJORITY OF VALLEY LOCALES WILL SEE
RAIN...WITH THE BULK OF THE SNOW TO EXIST ABOVE 6500-7000FT. GIVEN
THE COPIOUS AMOUNT OF MOISTURE...SNOW ACCUMULATIONS WILL BE
SIGNIFICANT ON THE HIGHER PEAKS. A WINTER WEATHER ADVISORY IS
ALREADY IN PLACE FOR THE SOUTHERN AND CENTRAL MOUNTAINS AND HIGH
POINTS ALONG THE SAN RAFAEL SWELL THROUGH SATURDAY.

WILL MAKE MINOR UPDATES MAINLY TO SPREAD MENTIONABLE POPS
FASTER/FARTHER INTO THE NORTH FOR TONIGHT.

&&

.AVIATION...CIGS AT THE SLC TERMINAL ARE EXPECTED TO LOWER TO NEAR
6K FT AGL BY 05Z AS A WEAK DISTURBANCE MOVES ACROSS NORTHERN UTAH.
THERE IS A 40 PERCENT CHANCE THAT CIGS WILL REMAIN ABOVE 7K FT AGL
THROUGH 06-07Z. WINDS WILL LIKELY REMAIN LIGHT SOUTHERLY THROUGH THE
NIGHT.

$$

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WINTER WEATHER ADVISORY UNTIL 4 PM MST SATURDAY FOR UTZ010-013-
     517-518.

WY...NONE.
&&

$$

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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