Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 020337
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
937 PM MDT SAT AUG 1 2015

.SYNOPSIS...MOISTURE OVER EXTREME SOUTHERN AND EASTERN UTAH WILL
SPREAD NORTHWARD ACROSS THE REGION SUNDAY. A DRIER SOUTHWESTERLY
FLOW WILL FOLLOW FOR EARLY NEXT WEEK.

&&

.SHORT TERM (UNTIL 12Z TUESDAY)...MOISTURE POOLED ACROSS FAR
SOUTHERN THROUGH EAST-CENTRAL UTAH THIS EVENING /PWAT VALUES
OF 1 INCH PLUS/ WILL WORK NORTH ACROSS MOST OF THE STATE BY LATE
SUNDAY. A VORTICITY MAX IDENTIFIED BY THE VARIOUS MODEL GUIDANCE
OVER THE LOWER COLORADO VALLEY THIS EVENING WILL BECOME BETTER
ORGANIZED AS IT TRAILS THE MOISTURE NORTHWARD SUNDAY. THIS SLOW
MOVING DYNAMIC FEATURE SHOULD BRING SCATTERED CONVECTION TO MUCH
OF THE STATE...WITH NORTHERN AND CENTRAL UTAH IN A GOOD POSITION
FOR SHOWERS/STORMS.

CONVECTION SO FAR THIS AFTERNOON AND EARLY EVENING HAS BEEN HIGH-
BASED AND ISOLATED ACROSS SOUTHWEST UTAH. A SECOND AREA OF
ISOLATED THUNDERSTORMS HAS POPPED UP OVER EAST-CENTRAL UTAH WHERE
A LIGHT BUT SOMEWHAT DEEP SOUTHEAST FLOW IS CREATING MOISTURE
CONVERGENCE INTO THE DRIER AIR TO THE NORTH. NOT LOOKING AT A
DRAMATIC INCREASE IN AREAL COVERAGE OVERNIGHT...THOUGH WOULD NOT
BE TOO SURPRISED TO SEE A STORM OR TWO AT TIMES NEAR THE MOISTURE
DISCONTINUITY OVERNIGHT.

FOR SUNDAY THE ADVANCING VORTICITY MAX COMBINED WITH WHAT LOOKS TO
BE UNUSUALLY STRONG MOIST WARM ADVECTION SHOULD LEAD TO FAIRLY
STRONG LIFT...ESPECIALLY ACROSS CENTRAL AND NORTHERN UTAH INTO
SUNDAY EVENING. STRONG LIFT AND RELATIVELY SLOW STORM MOTIONS
SUGGESTS THE POTENTIAL FOR HEAVY RAIN WITH THE STRONGER
SHOWERS/STORMS.

SCATTERED CONVECTION WILL LIKELY CONTINUE ACROSS THE NORTHERN
THIRD OF UTAH LATE SUNDAY NIGHT THROUGH MONDAY MORNING AS THE SLOW
MOVING VORTICITY MAX MOVES THROUGH THE AREA. DYNAMIC FORCING WILL
WANE QUICKLY BEHIND THE EXITING SYSTEM...THOUGH WITH ENOUGH
RESIDUAL MOISTURE IN PLACE WOULD STILL LOOK AT THE POSSIBILITY OF
ISOLATED TERRAIN-BASED CONVECTION THROUGH MONDAY EVENING.


.PREVIOUS LONG TERM (AFTER 12Z TUESDAY)...THE PRIMARY SHORTWAVE
TROUGH WILL CONTINUE TO EXIT TO THE NORTH THROUGH THE DAY
TUESDAY...WITH A DRIER AIRMASS MOVING INTO MUCH OF THE AREA ON THE
HEELS OF THE SHORTWAVE. HOWEVER...ENOUGH MOISTURE COULD LINGER IN
THE NORTHERN PORTIONS OF THE CWA TO ALLOW ISOLATED STORMS TO
PERSIST TUESDAY AND WEDNESDAY...AIDED BY WEAKER DISTURBANCES
PUSHING THROUGH THE REGION IN A MILD SOUTHWESTERLY FLOW. AFTER THE
LAST OF THESE WAVES EXITS WEDNESDAY NIGHT...EVEN DRIER AIR SHOULD
MOVE INTO THE ENTIRE CWA AS A RIDGE BUILDS OVER THE REGION...WITH
PRECIPITABLE WATER VALUES DROPPING BELOW 0.5 INCHES AREAWIDE.

THIS DRYING MAY BE RELATIVELY SHORT LIVED. A PACIFIC LOW IS FORECAST
TO MOVE INTO CALIFORNIA ON FRIDAY AND...DEPENDING ON THE DETAILS OF
PLACEMENT AND STRENGTH OF THIS LOW...COULD HELP DRAW MOISTURE INTO
SOUTHERN UTAH FROM THE SOUTH ON FRIDAY OR SATURDAY. HAVE MAINTAINED
THE GENERAL TREND OF INCREASING POPS ACROSS THE SOUTH STARTING
FRIDAY AFTERNOON/EVENING...AND THEN INTO MORE OF THE CWA ON
SATURDAY. HOWEVER...WITH SOME INCONSISTENCY IN THE MODELS...THE
DETAILS OF THIS POTENTIAL MOISTURE RETURN REMAIN LOW CONFIDENCE AT
THIS TIME.

&&


.AVIATION...INCREASING MID/HIGH LEVEL MOISTURE FROM THE SOUTH WILL
PRODUCE CEILINGS WELL ABOVE 12000 FEET THROUGH AT LEAST 15Z SUNDAY.
A WEATHER DISTURBANCE WORKING NORTH THROUGH THE STATE COULD BRING
A THREAT OF SHOWERS/THUNDERSTORMS INTO THE TERMINAL AREA BY LATE
SUNDAY AFTERNOON. LIGHT NORTHERLY WINDS AT MID-EVENING WILL WORK
BACK AROUND TO SOUTHEAST AROUND 04Z TO 05Z.

&&

.FIRE WEATHER...DEEP MOISTURE REMAINS CONFINED TO SOUTHERN/EASTERN
UTAH THIS EVENING UNDER HIGH PRESSURE ALOFT. THE RIDGE WILL WEAKEN
OVERNIGHT THROUGH SUNDAY AS A WEATHER DISTURBANCE MOVES NORTHWARD
ACROSS UTAH AND NEVADA. THIS WILL ALLOW SOUTHERLY FLOW TO DEVELOP
THAT WILL SPREAD THE MOISTURE NORTHWARD ACROSS ALL THE FIRE
DISTRICTS. AS A RESULT...COVERAGE OF SHOWERS AND THUNDERSTORMS
WILL INCREASE NOTICEABLY SUNDAY. DRIER AIR WILL START TO MOVE
BACK INTO THE STATE BEGINNING MONDAY AS THE WEATHER DISTURBANCE
EXITS THE AREA. GUSTY WINDS ARE POSSIBLE TUESDAY AND WEDNESDAY.

&&

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

$$

SHORT TERM/AVIATION...CONGER
LONG TERM...SCHOENING
FIRE WEATHER...TRAPHAGAN

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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