Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 261603
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1003 AM MDT SAT JUL 26 2014

.SYNOPSIS...MONSOONAL MOISTURE ACROSS SOUTHERN AND CENTRAL UTAH
WILL SLOWLY WORK ITS WAY NORTHWARD THROUGH THE WEEKEND...AND
REMAIN IN PLACE AREAWIDE THROUGH EARLY NEXT WEEK.

&&

.DISCUSSION...THE ELONGATED MID LEVEL RIDGE AXIS EXTENDING FROM
THE SOUTHERN PLAINS WEST ACROSS THE DESERT SOUTHWEST WILL EXPAND
NORTH AND WEST TODAY ALLOWING ITS AXIS TO ORIENT ACROSS WESTERN
AND SOUTHWESTERN UTAH BY TONIGHT. RETURN FLOW MOISTURE CONTINUES
TO STREAM AROUND THE PERIPHERY OF THIS HIGH...AND AS IT HAS FOR
THE LAST FEW DAYS CONTINUES TO ORIENT ALONG SOUTHWESTERLY
STREAMLINES ACROSS THE SOUTHERN HALF OF THE CWA FOR THE TIME
BEING. AFOREMENTIONED EXPANSION WILL ALLOW STREAMLINES TO ORIENT
MORE SOUTHERLY OVERNIGHT TONIGHT ALLOWING MOISTURE TO BEGIN
SPREADING MORE TO THE NORTH OVER THE NEXT 24 HOURS.

A SHORT WAVE AND ASSOCIATED CIRCULATION...REMNANT OF CONVECTION
ACROSS CENTRAL ARIZONA LAST EVE...IS TRACKING SLOWLY WEST-EAST
ACROSS THE UT/AZ BORDER THIS MORNING. WEAK BUT RELATIVELY BROAD
LIFT FROM THIS FEATURE IS NOTED IN SATELLITE EXPANDING THE
ASSOCIATED CLOUD FIELD NORTH TO ABOUT INTERSTATE 70. UPDATED
EARLIER TO ADD MENTION OF ISOLATED SHOWERS/STORMS THIS MORNING FROM
ROUGHLY KANAB NORTHEAST TO HANKSVILLE AND INCREASE CLOUD COVER TO
MOSTLY CLOUDY FOR THOSE AREAS. A WEAK DEFORMATION AXIS FROM THIS
WILL LIKELY PROMOTE THE MOST SIGNIFICANT CONVECTIVE ACTIVITY
ACROSS THE SOUTH-CENTRAL MOUNTAINS SOUTHWEST ACROSS THE
SOUTHWESTERN UTAH THIS AFTERNOON. A FEW HEAVY RAINERS WILL BE
POSSIBLE THOSE AREAS DUE TO WEAK STEERING FLOW ALOFT...PWAT
BETWEEN 1-1.2 INCHES AND SURFACE DEW POINTS IN THE MID 50S.

ALTHOUGH MOISTURE ACROSS MANY AREAS OF THE SOUTH/EAST REMAINS DEEP
ENOUGH FOR WET STORMS TODAY...THE NORTHERN PERIPHERY IN WEST
CENTRAL UTAH SHOULD SEE MORE DRY AND WINDY STORMS WHERE MOISTURE
GRADIENT DROPS OFF SHARPLY. SEE FIRE WEATHER BRIEFING REGARDING
THIS FOR MORE DETAIL.

AS MENTIONED MOISTURE WILL TREND NORTH OVER THE NEXT 24
HOURS...BUT ONLY MODERATELY SO. A MORE PRONOUNCED SURGE IS
EXPECTED MONDAY THROUGH TUESDAY MORNING AS AN UPPER LOW CURRENTLY
OVER NORTHERN MEXICO TRACK NORTH ACROSS WESTERN UTAH. TIMING OF
THIS WAVE PER NAM/GFS AND HI RES GUIDANCE SUGGEST THAT AN
OVERNIGHT/EARLY MORNING PASSAGE OF THIS WILL OCCUR ACROSS NORTHERN
UTAH...LIKELY BRINGING A COOLER AND MORE STRATIFORM EVENT TO THE
WASATCH FRONT AT THAT TIME.

RELATIVELY DEEP MOISTURE SHOULD REMAIN IN PLACE INTO MID WEEK OF
NEXT WEEK...BUT CONFIDENCE IN LARGE SCALE PATTERN EVOLUTION AND
SPECIFICALLY THE LOCATION OF THE HIGH AND ASSOCIATED AXIS WANES.
ECMWF/GFS CONTINUE TO DISPLAY SUBTLE DIFFERENCES WHICH HAVE FAIRLY
LARGE CONSEQUENCES ON STREAMLINES AND MOISTURE ADVECTION
TRAJECTORIES OVER THE CWA. WILL LOOK AT THIS MORE CLOSELY WHEN THE
FULL SUITE OF 12Z GUIDANCE ARRIVES.

&&

.AVIATION...LIGHT NORTHWEST WINDS ARE EXPECTED TO INCREASE ABOVE 8
KNOTS BY 18Z AT THE KSLC TERMINAL. THESE NORTHWESTERLY WINDS ARE
THEN EXPECTED TO CONTINUE INTO LATE EVENING BEFORE RETURNING
TO THE SOUTHEAST FOR THE OVERNIGHT HOURS. MOSTLY CLEAR TO CLEAR
SKIES WILL ALLOW VFR CONDITIONS TO HOLD THROUGH THE VALID TAF
PERIOD.

&&

.FIRE WEATHER...MOISTURE REMAINS IN PLACE ACROSS SOUTHERN AND
EASTERN UTAH TODAY WITH A DRIER AIRMASS ACROSS THE NORTHWEST.
SCATTERED MOSTLY WET THUNDERSTORMS ARE EXPECTED IN THE MOIST AIRMASS
WITH DRIER STORMS ALONG THE MOISTURE BOUNDARY ACROSS WEST CENTRAL
UTAH. EXPECT SUFFICIENT COVERAGE OF DRY STORMS IN THIS AREA TO
WARRANT UPGRADING THE EXISTING WATCH TO A WARNING. IT APPEARS THE
GREATEST THREAT FOR THUNDERSTORMS IN THIS AREA WILL BE MID AFTERNOON
THROUGH THE EVENING AND HAVE SHIFTED THE START TIME OF THE WARNING
TO LATER IN THE DAY.

MOISTURE WILL INCREASE NORTHWARD SUNDAY AND THE THREAT OF DRY
THUNDERSTORMS SHIFTS INTO THE NORTHWEST DESERTS. HOWEVER...EXPECT
MOST DRY STORM ACTIVITY TO STAY ALONG THE NEVADA BORDER WITH ONLY
ISOLATED CELLS FARTHER EAST.

ADDITIONAL MOISTURE MOVES NORTH INTO THE DISTRICT ON MONDAY AS A
WEAK DISTURBANCE MOVES INTO THE AREA. THIS WEAK BUT MOIST SYSTEM
WILL LIFT THROUGH SOUTHERN UTAH MONDAY...CENTRAL UTAH MONDAY NIGHT
AND NORTHERN UTAH ON TUESDAY ACCOMPANIED BY FAIRLY WIDESPREAD
SHOWERS AND THUNDERSTORMS.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 11 PM MDT THIS
     EVENING FOR UTZ492.

WY...NONE.
&&

$$

MERRILL/WILENSKY


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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