Area Forecast Discussion
Issued by NWS Salt Lake City, UT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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 011145
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
545 AM MDT SUN MAY 1 2016

.SYNOPSIS...A LOW PRESSURE SYSTEM WILL WORK ITS WAY THROUGH THE
DESERT SOUTHWEST TODAY. HIGH PRESSURE ALOFT WILL RETURN TO THE
INTERIOR WEST BY THE MIDDLE OF NEXT WEEK.

&&

.SHORT TERM (THROUGH 18Z WEDNESDAY)...THE LARGE-SCALE PATTERN THIS
MORNING CONSISTS OF AN UPPER LOW CENTERED OVER ARIZONA WITH A DEEP-
LAYER EASTERLY FLOW ACROSS NORTHERN UTAH. LATEST MSAS ANALYSIS SHOWS
A 11MB SURFACE PRESSURE GRADIENT BETWEEN KLND AND KSLC WHILE MODELS
INDICATE H7 WINDS IN EXCESS OF 40KT ACROSS THE WASATCH RANGE ALONG
WITH A THERMAL GRADIENT OF AROUND 5-6C. AS A RESULT...STRONG
DOWNSLOPE WINDS DEVELOPED OVERNIGHT WITH MANY AREAS PEAKING JUST
RECENTLY. THE STRONGEST WINDS HAVE BEEN ALONG THE NORTHERN WASATCH
FRONT AND ESPECIALLY IN THE FAVORED FARMINGTON AND CENTERVILLE
AREAS. A HIGH WIND WARNING REMAINS IN PLACE FOR THE NORTHERN WASATCH
FRONT.

ELSEWHERE ACROSS NORTHERN UTAH...WINDS HAVE BEEN A BIT WEAKER AND
MORE LOCALIZED. IN THE CACHE VALLEY AND SALT LAKE VALLEYS GUSTS HAVE
REACHED THE 40-50 MPH RANGE BUT MOSTLY NEAR CANYONS. WIND ADVISORIES
REMAIN IN PLACE FOR THOSE AREAS. IN UTAH COUNTY HOWEVER...THE WINDS
HAVE NOT REALLY MATERIALIZED. HOWEVER...WIND SPEEDS DID TREND UPWARD
IN PROVO CANYON OVER THE PAST COUPLE OF HOURS. HAVE LEFT THE
ADVISORY IN PLACE THERE WITH THE IDEA THAT LOCALIZED STRONGER CANYON
WINDS COULD STILL OCCUR INTO THE MORNING HOURS SINCE WINDS IN
GENERAL ARE STILL PEAKING...BUT THERE IS A CHANCE THAT UTAH COUNTY
COULD ESCAPE WITHOUT SEEING THE ADVISORY-LEVEL WINDS.

A DOWNWARD TREND IN WIND SPEEDS IS EXPECTED THIS AFTERNOON AS H7
WINDS AND THERMAL PACKING RELAX A BIT. HOWEVER...GIVEN THE CURRENT
WIND SPEEDS...EVEN WITH A MODERATE DECREASE...THE WINDS WILL REMAIN
QUITE GUSTY. THE WINDS MAY PICK UP AGAIN THIS EVENING BEFORE
DECREASING LATE TONIGHT AS SUPPORT ALOFT WANES LEAVING ONLY THE
EASTERLY SURFACE GRADIENT.

BESIDES WINDS...SOME SHOWERS ARE STILL IN THE FORECAST FOR TODAY.
THE AFOREMENTIONED LOW OVER ARIZONA WILL LIFT NORTHEAST TOWARDS THE
FOUR CORNERS AREA...ALTHOUGH IT IS PROGGED TO WEAKEN AND FILL BEFORE
IT GETS THERE. HOWEVER...THIS TRACK IS EXPECTED TO SPREAD
PRECIPITATION INTO SOUTHEAST UTAH THIS MORNING. BY
AFTERNOON...ALTHOUGH THE DYNAMICS WILL HAVE SIGNIFICANTLY
WEAKENED...LINGERING MOISTURE AND SOME INSTABILITY WILL ALLOW A FEW
SHOWERS AND THUNDERSTORMS TO DEVELOP...MAINLY ACROSS THE MOUNTAINS
OF EASTERN...CENTRAL AND SOUTHERN UTAH AND ADJACENT VALLEYS AS WELL
AS SOUTHEAST UTAH.

TOMORROW...A WEAK DISTURBANCE WILL TRACK INTO ARIZONA. WITH THE
AIRMASS STILL SOMEWHAT UNSTABLE WITH SOME MOISTURE STILL IN
PLACE...A FEW SHOWERS ARE POSSIBLE ONCE AGAIN...WITH THE BEST CHANCE
ACROSS THE MOUNTAINS AND SOUTH. FINALLY...HIGH PRESSURE WILL START
TO BUILD INTO THE AREA ON TUESDAY. A DRYING AND WARMING TREND WILL
ENSUE WITH TEMPERATURES FINALLY RETURNING TO ABOVE NORMAL READINGS.

.LONG TERM (AFTER 18Z WEDNESDAY)...RIDGE AXIS SLIDES TO THE EAST OF
THE FORECAST AREA WEDNESDAY AFTERNOON ALLOWING A BROAD SOUTHERLY
FLOW ALOFT TO COMBINE WITH A FAVORABLE SURFACE GRADIENT TO ACHIEVE A
WELL MIXED AIR MASS. AS A RESULT TEMPERATURES SHOULD PEAK IN THE
UPPER 70S TO NEAR 80 IN MOST VALLEYS...EXCEPT UPPER 80S IN DIXIE. EC
TRIES TO DEVELOP SOME QPF OVER THE SOUTHWEST BUT DO NOT SEE WHAT IS
DRIVING THAT SO KEPT FORECAST DRY. BY THURSDAY...THE LONG WAVE
TROUGH HAS BARELY MOVED EAST ALONG THE WEST COAST AS IT PINCHES OFF
AS A CLOSED LOW OFF THE SOUTHERN CALIFORNIA COAST. THIS WILL KEEP
THE BROAD SOUTHERLY FLOW IN PLACE WITH TEMPS REMAINING VERY
WARM...EXCEPT THE SOUTHWEST PORTION UTAH WHERE A SLIGHT DIP IN TEMPS
EXPECTED DUE TO ADDITIONAL CLOUD COVER AND SOME 700MB COOLING.

BY FRIDAY AFTERNOON THE LOW IS BARELY INTO SOUTHERN CAL BUT A LOBE
OF ENERGY IS SWINGING NORTHWARD ACROSS THE CWA WHICH IS SEEN IN BOTH
THE GFS AND EC BUT NEITHER REALLY SHOW MUCH INCREASE IN 700MB
MOISTURE. WAS ABOUT TO INCREASE THE THREAT OF SHOWERS FOR FRIDAY BUT
THIS LACK OF 700 MB MOISTURE IS DISCONCERTING. HAVE GONE WITH NEAR
CLIMO POPS FOR NOW.

THE CLOSED MOVES NORTHEAST INTO NEVADA SATURDAY BUT ONCE AGAIN THE
MOISTURE DOES NOT APPEAR TO BE VERY IMPRESSIVE AT MID LEVELS SO KEPT
THE POPS NEARLY SIMILAR TO THOSE OF FRIDAY. BROUGHT TEMPS DOWN SOME
AS THE 700 MB TEMPS DROP SEVERAL MORE DEGREES C.

MODELS DIVERGE GREATLY BY SUNDAY AS THE GFS DRIVES THE LOW SOUTHEAST
TOWARDS ARIZONA DUE TO AN INCOMING TROUGH OVER THE PACIFIC
NORTHWEST. HOWEVER THE EC MOVES AND OPENS UP THE LOW TOWARDS THE
NORTHEAST ACROSS THE CWA. KEPT POPS SLIGHTLY HIGHER THAN CLIMO AS
MODELS UNCERTAINTY KEEPS CONFIDENCE LOW.

&&

.AVIATION...NEARBY DOWNSLOPE WINDS ALONG THE WASATCH FRONT WILL CAUSE
PERIODS OF ERRATIC WIND DIRECTIONS AT THE SLC TERMINAL INTO THIS
AFTERNOON. WINDS WILL MOST LIKELY WANDER BETWEEN NORTH AND SOUTHEAST
THROUGH 19Z BUT EAST-SOUTHEAST SHOULD BE THE MOST DOMINANT WITH
GUSTS AS HIGH AS 25-30KT. AFTER 19Z WINDS SHOULD BECOME
PREDOMINANTLY NORTHWEST WITH GUSTS BETWEEN 15 AND 20KTS.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WIND ADVISORY UNTIL 3 PM MDT THIS AFTERNOON FOR UTZ001-003-004.

     HIGH WIND WARNING UNTIL 3 PM MDT THIS AFTERNOON FOR UTZ002.

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.