Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 191653
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1053 AM MDT TUE AUG 19 2014

.SYNOPSIS...A MOIST MONSOONAL AIRMASS WILL RESIDE ACROSS THE
REGION TODAY. A WEAK WEATHER SYSTEM WILL MAINTAIN AN UNSETTLED
PATTERN THROUGH THE REMAINDER OF THE WEEK...FOLLOWED BY A DRYING
TREND THIS WEEKEND.

&&

.DISCUSSION...DEEP MOISTURE IN PLACE COUPLED WITH BROAD ASCENT
OWING TO AN ONGOING PRECIP EVENT ALONG A ZONE FROM SOUTHWESTERN
UTAH NORTHEAST TO THE WASATCH FRONT. H5 ANALYSIS INDICATES A
CLOSED LOW RESIDING ALONG THE CENTRAL CALIFORNIA COAST WITH AREA
OF UPPER DIFFLUENCE FOCUSING OVER SOUTHWEST/WEST CENTRAL UTAH.
THE LEFT EXIT REGION OF THE ATTENDANT JET HAS TRANSITIONED INTO
NORTHWESTERN ARIZONA THIS MORN...AND COUPLING EXISTS ACROSS
CENTRAL/NORTHERN UTAH WHERE THE RIGHT ENTRANCE OF A NORTHERN
BRANCH JET CORE EXISTS ACROSS WESTERN WYOMING. HAVE THUS FAR SEEN
PRIMARILY STRATIFORM RAINFALL MOST AREAS WITH SOME EMBEDDED
CONVECTION IN AND AROUND DIXIE. HIGHEST RAINFALL OBS/ESTIMATES
EXIST ACROSS THE SOUTHWEST WHERE .5 TO 1.3 INCHES OF RAIN HAS
FALLEN OVER THE LAST SEVERAL HOURS. BENEATH THE UPPER COUPLING
SHORT WAVE ENERGY EXISTS OVER NORTH CENTRAL UTAH WHERE A MID LEVEL
CLOSED CIRCULATION EXISTS VICINITY KSLC.

DYNAMIC LIFT DRIVING CURRENT PRECIP WILL SLOWLY SHIFT EAST ACROSS
THE STATE TODAY AS THE UPPER LOW GRADUALLY NOSES ONSHORE.
SIGNIFICANT CLOUD COVER EXISTS BUT HAVE NOTED SOME THINNING ACROSS
EASTERN/SOUTHEASTERN UTAH ALLOWING SOME WARMING FROM ROUGHLY PRICE
TO LAKE POWELL. ANTICIPATE EMBEDDED CONVECTION WILL BE MOST
PRONOUNCED ACROSS THESE AREAS THIS AFTERNOON. THUS FAR PRECIP
RATES HAVE REMAINED MANAGEABLE BUT EXPECT MANY NORMALLY DRY WASHES
HAVE SOME FLOWS ACROSS THE SOUTHWEST...AND AFTERNOON CONVECTIVE
POTENTIAL ACROSS THE EAST/SOUTHEAST COULD BE SUFFICIENT FOR
LOCALLY HEAVY RAIN AND HIGHER PI RATES. HAVE MAINTAINED FLASH
FLOOD WATCH ACROSS MUCH OF CENTRAL AND SOUTHERN UTAH AS SUCH.

AS BEST LIFT SHIFTS EAST THIS AFTERNOON/EVE...HRRR/RAP13 SUGGESTS
A TAPERING OF PRECIP ACROSS THE WESTERN THIRD OF THE AREA...AND
EXPECT A MORE STABLE ENVIRONMENT TO EXIST WITHIN A RAINCOOLED
AIRMASS THERE. THAT SAID...WESTERN EDGE OF CLOUD SHIELD OVER
EASTERN NEVADA WILL LIKELY BE A FOCUS FOR MORE CONVECTIVE CELLS
LATE DAY THAT COULD WORK EAST INTO THE WEST CENTRAL/NORTHWESTERN
DESERTS AND POSSIBLY WASATCH FRONT OVERNIGHT. NOT OVERLY CONFIDENT
IN THAT AT THIS TIME DUE TO ANTICIPATED STABILITY BUT WILL DELVE
IN A BIT DEEPER AND MONITOR TRENDS FOR THE AFTERNOON PACKAGE.

UPDATED EARLIER TO INCREASE POPS/CLOUDS FOR TODAY AS ONLY UPDATE.
GOING FORECAST LOOKS ON TRACK. PREVIOUS LONG TERM BELOW...

THE CA LOW IS FORECAST TO EVOLVE INTO AN OPEN WAVE AND SLOWLY
SWING EASTWARD ACROSS THE REGION DURING THE WEDNESDAY/THURSDAY
TIMEFRAME...AS A LONGWAVE TROUGH BECOMES ESTABLISHED ACROSS THE
PACIFIC NORTHWEST/NORTHERN ROCKIES. ALTHOUGH THE AIRMASS WILL DRY
CONSIDERABLY FROM WHAT IS CURRENTLY BEING OBSERVED ACROSS THE
REGION...LINGERING MOISTURE COMBINED WITH A CYCLONIC FLOW ALOFT
SHOULD YIELD ISOLATED TO SCATTERED CONVECTION THROUGH THE
REMAINDER OF THE WEEK...AND HAVE BUMPED POPS 10-20 PERCENT AS A
RESULT. THIS FLOW WILL ALSO KEEP TEMPERATURES A BIT BELOW
CLIMATOLOGICAL NORMS THROUGH THE REMAINDER OF THE WEEK.

THE 00Z EC AND GFS DIVERGE WITH THE HANDLING OF THE LONGWAVE
TROUGH BY THE THE WEEKEND...WITH THE GFS FAVORING A LESS AMPLIFIED
SOLUTION WHILE THE EC IS DEEPER AND PUSHES A SHORTWAVE TROUGH INTO
FAR NORTHERN UT LATE SATURDAY/SUNDAY. FOR NOW HAVE MAINTAINED A
DRYING/WARMING TREND FOR LATE IN THE PERIOD.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED AT THE SLC TERMINAL
THROUGHOUT THE DAY. SOUTHEAST WINDS ARE EXPECTED TO SHIFT TO THE
NORTHWEST BETWEEN 21Z AND 23Z. HOWEVER...WITH A RAIN-COOLED ENVIRONMENT
THERE IS A 40 PERCENT CHANCE THIS SHIFT WILL NOT OCCUR. SHOWERS DEVELOPING
IN THE VICINITY OF THE TERMINAL LATE THIS MORNING THROUGH THE AFTERNOON
MAY RESULT IN PERIODS OF GUSTY AND/OR ERRATIC WINDS.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...FLASH FLOOD WATCH UNTIL 10 PM MDT THIS EVENING FOR UTZ010-
     012>014-016-019>021-517-518.

WY...NONE.
&&

$$

MERRILL/VERZELLA/SEAMAN


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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