Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 291625
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1025 AM MDT FRI APR 29 2016

.SYNOPSIS...THE LOW PRESSURE SYSTEM OVER COLORADO WILL EXIT EAST
INTO THE PLAINS LATE TONIGHT. A SECOND STORM SYSTEM WILL FOLLOW
FOR THIS WEEKEND...BRINGING A RETURN OF COOL AND UNSETTLED
CONDITIONS TO MAINLY SOUTHERN UTAH THIS WEEKEND.

&&

.DISCUSSION...THE UPPER LOW CURRENTLY CENTERED OVER COLORADO WILL
CONTINUE ON A SLOW EAST-NORTHEAST TRACK INTO THE CENTRAL PLAINS
STATES THIS WEEKEND. A WEAK VORTICITY LOBE ROTATING SOUTH ON THE
WEST SIDE OF THE COLORADO LOW WILL MAINTAIN SOME LIGHT SHOWER
ACTIVITY ACROSS MOST AREAS OF UTAH/SOUTHWEST WYOMING THROUGH EARLY
THIS EVENING.

THE SHORTWAVE CURRENTLY ALONG THE PACIFIC NORTHWEST COAST WILL
CONTINUE ON A SOUTH-SOUTHEAST TRAJECTORY AS THE UPSTREAM RIDGE
BUILDS OVER THE EASTERN PACIFIC. THIS SHORTWAVE IS STILL EXPECTED
TO DEVELOP INTO A CLOSED LOW AS IT MOVES THROUGH SOUTHERN NEVADA
LATE TONIGHT/EARLY SATURDAY. FROM THERE THIS FEATURE WILL SETTLE
INTO CENTRAL ARIZONA WHERE IT WILL GRADUALLY WEAKEN LATE SUNDAY
THROUGH MONDAY. ABUNDANT MOISTURE ALONG WITH A BROAD AREA OF
SYNOPTIC-SCALE LIFT NORTH OF THE LOW CENTER WILL BRING AN
INCREASING AREA OF VALLEY RAIN/MOUNTAIN SNOW ACROSS SOUTHERN UTAH
ON SATURDAY. PRECIP WILL BECOME MORE CONCENTRATED ACROSS
SOUTHEAST UTAH LATE IN THE WEEKEND AND THE REMNANT OF THE UPPER
LOW DRIFT NORTH TO THE FOUR CORNERS REGION.

THE HEADLINE ISSUE THIS WEEKEND WILL BE THE POTENTIAL FOR A
DOWNSLOPE HIGH WIND EVENT ALONG THE NORTHERN WASATCH FRONT/CACHE
VALLEY SATURDAY NIGHT THROUGH SUNDAY. THE SETUP FOR THIS EVENT
WILL BE THE INCREASING DEEP LAYER EASTERLY FLOW ALOFT BETWEEN THE
UPPER HIGH CENTERED ACROSS SOUTH-CENTRAL CANADA AND UPPER LOW
MOVING FROM COLORADO INTO THE CENTRAL PLAINS STATES LATE TONIGHT.
THE RESULTANT 40+ KTS NEAR 700MB COLD ADVECTION EASTERLY FLOW
ACROSS SOUTHWEST WYOMING AND NORTHERN NEVADA AND AN 8-10MB
NORTHEAST SURFACE PRESSURE GRADIENT BETWEEN CENTRAL WYOMING AND
NORTHERN UTAH SUPPORTS A RATHER SUBSTANTIAL DOWNSLOPE HIGH WIND
EVENT. WEST TO EAST CROSS SECTIONS THROUGH THE NORTHERN WASATCH
RANGE SHOW THETA SURFACE PACKING JUST ABOVE THE TERRAIN WHICH
EXTENDS DOWN ALONG THE WEST SLOPES INTO THE WASATCH FRONT. THIS
PATTERN WOULD INDICATE A STRONG DOWNSLOPE AND/OR BREAKING WAVE
HIGH WIND EVENT FOR THE NORTHERN WASATCH FRONT AND POSSIBLY INTO
THE CACHE VALLEY. WILL LIKELY BE ISSUING AN HIGH WIND WATCH IN THE
NEXT FORECAST PACKAGE.

&&

.AVIATION...WINDS AT THE SLC TERMINAL ARE EXPECTED TO REMAIN
MOSTLY LIGHT AND NORTHERLY THROUGH 02-03Z THIS EVENING. NEARBY
SHOWERS EXPECTED THIS AFTERNOON AND EARLY EVENING MAY CREATE
VARIABLE WINDS AND LOCALLY BREEZY CONDITIONS. INCREASING EASTERLY
GRADIENT WINDS SATURDAY MORNING MAY TURN THE WINDS NORTHERLY EVEN
NORTH EASTERLY EARLIER THAN NORMAL SATURDAY. VFR CONDITIONS WILL
PREVAIL THROUGH THE TAF PERIOD.

&&

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

$$

PUBLIC...CONGER
AVIATION...DEWEY

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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