Area Forecast Discussion
Issued by NWS Salt Lake City, UT

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS65 KSLC 301203
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
603 AM MDT SAT APR 30 2016

.SYNOPSIS...THE NEXT PACIFIC STORM SYSTEM WILL CROSS FROM
SOUTHERN NEVADA INTO ARIZONA AND SPREAD MOISTURE ACROSS FAR SOUTHERN
AND EASTERN UTAH THIS WEEKEND. HIGH PRESSURE ALOFT WILL RETURN TO
THE INTERIOR WEST BY THE MIDDLE OF NEXT WEEK.

&&

.SHORT TERM (THROUGH 18Z TUESDAY)...THE NEXT UPPER LOW IS CURRENTLY
SEEN ON WATER VAPOR IMAGERY SLIDING DOWN THE CENTRAL/SOUTHERN SIERRA
NEVADA. DIFFLUENT FLOW AHEAD OF THE LOW HAS ALLOWED PRECIPITATION TO
DEVELOP INTO SOUTHWEST UTAH OVERNIGHT AND WHERE IT WILL CONTINUE
THIS MORNING. OTHERWISE...EXPECT A RELATIVELY QUIET START TO THE DAY
ACROSS THE REST OF THE FORECAST AREA WITH JUST A FEW SPOTTY SHOWERS
EXPECTED.

THE LOW WILL CROSS LAKE MEAD THIS AFTERNOON AND HEAD INTO ARIZONA
WHERE IT WILL LINGER THROUGH THE NIGHT. DUE TO THE SOUTHERLY TRACK
OF THE STORM...THE BULK OF THE PRECIPITATION ASSOCIATED WITH IT WILL
SHIFT SOUTH OF UTAH THIS AFTERNOON. HOWEVER...AMPLE MOISTURE WILL
REMAIN IN PLACE WITH ENOUGH INSTABILITY TO DRIVE AFTERNOON
CONVECTION ACROSS THE AREA. TEMPERATURES WILL REMAIN BELOW NORMAL
ACROSS MUCH OF THE AREA TODAY DESPITE AN EXPECTED SLIGHT WARMING
TREND ACROSS NORTHERN AND CENTRAL UTAH.

THE LOW WILL START TO LIFT NORTHEAST TOWARDS THE FOUR CORNERS REGION
TOMORROW MORNING BUT IS EXPECTED TO WEAKEN CONSIDERABLY BEFORE
MAKING IT THERE. AS A RESULT...PRECIPITATION WILL TEND TO INCREASE
ACROSS SOUTHEAST UTAH LATE TONIGHT INTO TOMORROW MORNING...THEN TURN
MORE SHOWERY FOR THE AFTERNOON. A GENERAL DRYING TREND IS EXPECTED
ACROSS THE NORTHERN AND WESTERN PORTIONS OF THE AREA.

THE MOST SIGNIFICANT IMPACT WITH THIS STORM IS STILL EXPECTED TO BE
ASSOCIATED WITH DOWNSLOPE AND CANYON WINDS ALONG THE WASATCH FRONT.
WINDS ALOFT ARE ALREADY STARTING TO TURN NORTHEASTERLY AND WILL
BECOME MORE EASTERLY WHILE STRENGTHENING THIS EVENING. SAME WITH THE
SURFACE PRESSURE GRADIENT ACROSS NORTHEAST UTAH. MODELS STILL
DEPICTING 50KT CROSS-BARRIER FLOW AT 700MB WITH WITH A 4-5C THERMAL
GRADIENT ACROSS THE WASATCH RANGE LATE TONIGHT THROUGH TOMORROW
MORNING. STILL LOOKING FAIRLY GOOD FOR A DOWNSLOPE WIND EVENT ALONG
THE WASATCH FRONT AND CACHE VALLEY WITH PARTICULAR EMPHASIS IN WEBER
AND DAVIS COUNTIES AS WELL AS PERHAPS THE CACHE VALLEY. GUSTY BUT
MORE LOCALIZED STRONG WINDS ARE ALSO EXPECTED IN THE SALT LAKE
VALLEY AND PORTIONS OF UTAH COUNTY. THE WINDS LOOK TO RELAX A BIT BY
SUNDAY AFTERNOON BUT REMAIN GUSTY. A BRIEF INCREASE IN WINDS IS
EXPECTED AGAIN TOMORROW EVENING BEFORE THE 700MB SUPPORT STARTS TO
WANE. HAVE LEFT THE HIGH WIND WATCH IN PLACE FOR THE MORNING PACKAGE
WITH THE IDEA THAT IT CAN BE UPGRADED DURING THE DAY AFTER
COORDINATION WITH PARTNERS.

FOR MONDAY AND MONDAY NIGHT...LINGERING MOISTURE ALONG WITH SOME
WEAK RIPPLES IN THE FLOW WILL CONTINUE TO ALLOW FOR ISOLATED TO
SCATTERED CONVECTION ACROSS THE AREA. HOWEVER...THE TREND WILL BE
FOR LIGHTER AND LESS ORGANIZED AREAS OF PRECIPITATION.

.LONG TERM (AFTER 18Z TUESDAY)...THE GLOBAL MODELS ARE PRETTY MUCH
IN GOOD AGREEMENT IN THE BIG PICTURE THROUGH THIS EXTENDED PERIOD.
HOWEVER THE EC BECOMES A LITTLE SLOWER IN BRINGING IN THE NEXT
TROUGH TOWARDS THE END OF NEXT WEEK. THE EC ENSEMBLE IS A LITTLE
FASTER THAN THE OPERATIONAL AND NOT AS DEEP SO HAVE LEANED TOWARD
GFS FOR MOST OF GUIDANCE.

IN THE MEANTIME...STILL LOOKS LIKE ENOUGH MOISTURE REMAINS WITH WEAK
ENTRANCE REGION JET DYNAMICS TO CREATE LIFT ACROSS NORTHERN UTAH AND
SOUTHWEST WYOMING TUESDAY AFTERNOON AND EVENING FOR A THREAT OF
SHOWERS AND THUNDERSTORMS. AFTER THIS POINT...THE RIDGE BUILDS IN
STRONGLY BRINGING A COUPLE OF DRY AND WARM DAYS IN ACROSS THE CWA.

THE TEMPERATURES ARE EXPECTED TO TAKE A RUN INTO THE UPPER 70S TO
LOWER 80S ACROSS MOST VALLEYS WEDNESDAY AND THURSDAY AS THE 700MB
TEMPERATURES CLIMB TO BETWEEN PLUS 5 AND PLUS 8 DEGREES CELSIUS.

BOTH THE GFS AND EC SHOW THE TROUGH AT 500 MB CLOSING OFF OVER
SOUTHERN CALIFORNIA BY MIDDAY FRIDAY. THIS WILL PLACE UTAH UNDER A
FAVORABLE CYCLONIC AND DIFFLUENT FLOW FOR SCATTERED CONVECTION
FRIDAY THROUGH SATURDAY. THE EC HINTS AT A DRY SLOT MOVING INTO THIS
CIRCULATION BUT DETAILS UNCERTAIN SO BROAD BRUSHED AREA WITH SLIGHT
CHANCE TO CHANCE OF SHOWERS AND THUNDERSTORMS. THIS IS NOT THAT COLD
OF A SYSTEM THEREFORE SNOW LEVELS WILL MOST LIKELY REMAIN ABOVE 8000
FT.

&&

.AVIATION...WINDS AT THE SLC TERMINAL WILL LIKELY REMAIN NORTHERLY
THROUGH THIS AFTERNOON BEFORE TRENDING NORTHEAST THIS EVENING.
NEARBY DOWNSLOPE WINDS ALONG THE WASATCH FRONT WILL CAUSE ERRATIC
WINDS AT THE TERMINAL FROM EASTERLY TO AT TIMES SOUTHWEST...ALTHOUGH
WINDS WILL TYPICALLY REMAIN UNDER 20 MPH.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...HIGH WIND WATCH FROM LATE TONIGHT THROUGH SUNDAY AFTERNOON FOR
UTZ001-002.

WY...NONE.
&&

$$

CHENG/STRUTHWOLF

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)


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.