Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 232148
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
348 PM MDT WED JUL 23 2014

.SYNOPSIS...A PACIFIC NORTHWEST TROUGH WILL BRING A DRY COLD FRONT
INTO NORTHERN UTAH TOMORROW. OVER SOUTHERN AND EASTERN
UTAH...MOISTURE WILL LINGER OVER THE AREA THURSDAY AND FRIDAY
BEFORE A SLOW DRYING TREND BEGINS OVER THE WEEKEND.

&&

.DISCUSSION...SOUTHWEST FLOW IS DRAWING MOISTURE NORTHWARD INTO
THE FORECAST AREA THIS AFTERNOON. MOISTURE GRADIENT IS ORIENTED
NE/SW WITH PWS AROUND 1.0 INCH ON THE SOUTH SIDE AND MORE LIKE 0.5
TO 0.6 INCH ON THE NORTH SIDE. SHOWERS AND THUNDERSTORMS ARE
DEVELOPING THIS AFTERNOON...WITH THE BEST COVERAGE OVER THE HIGHER
TERRAIN ALONG THIS MOISTURE GRADIENT. CONVECTION WILL CONTINUE
INTO THE EARLY EVENING BEFORE WEAKENING WITH THE LOSS OF DAYTIME
HEATING. TEMPERATURES ARE WARM ACROSS THE STATE...PARTICULARLY
OVER NORTHERN UTAH WHERE SEVERAL WASATCH FRONT LOCATIONS HAVE SEEM
TEMPERATURES AT OR ABOVE 100F. OVERALL TEMPERATURES ARE RUNNING
2-3F ABOVE CLIMO OVER SOUTHERN UTAH AND IN EXCESS OF 5F ABOVE
THOSE VALUES OVER NORTHERN UTAH.

THE TROUGH CURRENTLY MOVING ONSHORE ALONG THE PACIFIC NORTHWEST
COAST WILL MOVE INTO IDAHO AND MONTANA BY TOMORROW AFTERNOON.
MOISTURE AND INSTABILITY WILL STAY WELL NORTH OF THE FORECAST
AREA...BUT THE SYSTEM IS PROGGED TO MOVE A DRY COLD FRONT INTO
NORTHERN UTAH DURING THE DAY THURSDAY...ALLOWING TEMPERATURES TO
COOL TO NEAR SEASONAL NORMALS BY FRIDAY. THE INFLUENCE OF THE
PASSING TROUGH WILL ALSO FLATTEN THE RIDGE OVER THE
REGION...TURNING THE FLOW ALOFT MORE WESTERLY. THIS WILL CHANGE
THE ORIENTATION OF THE MOISTURE AXIS OVER THE STATE TO MORE OF AN
EAST TO WEST DIRECTION AND MOVE SOME OF THE MOISTURE BACK SOUTH OF
THE AREA...RESULTING IN REDUCED COVERAGE OF AFTERNOON CONVECTION.

GLOBAL MODELS ALL INDICATE THAT THE RIDGE WILL REBOUND OVER THE
WEEKEND WITH THE FLOW ALOFT BECOMING FAIRLY LIGHT DURING THIS
TIME. THIS WILL ALLOW FOR A WARMING TREND WITH MOISTURE LINGERING
OVER SOUTHERN UTAH ON SATURDAY. THE FLOW MAY DEVELOP A BIT OF A
SOUTHERLY COMPONENT FOR SUNDAY...ALLOWING SOME MOISTURE TO SPREAD
NORTHWARD THOUGH PWS WILL BE DECREASING OVERALL. THE RIDGE IS
EXPECTED TO REMAIN IN PLACE THROUGH AT LEAST EARLY NEXT
WEEK...THOUGH MODELS CONTINUE TO DISAGREE ON THE DETAILS OF
MOISTURE TRENDS. GFS CONTINUES TO BE MORE BULLISH WITH BRINGING
MOISTURE INTO THE AREA COMPARED TO THE GFS.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL AT KSLC THROUGH THE TAF
PERIOD. NORTHWEST WINDS CURRENTLY ACROSS THE NORTHERN PORTIONS OF
THE AIRPORT PROPERTY ARE EXPECTED TO SPREAD THROUGH THE REMAINDER OF
THE TERMINAL BY 23Z...WITH WINDS RETURNING TO SOUTH AFTER 02-03Z.
HOWEVER...A 10 PERCENT CHANCE EXISTS THAT NORTHWEST WINDS WILL NOT
MAKE IT ALL THE WAY THROUGH THE TERMINAL TODAY.

&&

.FIRE WEATHER...THE MAIN FIRE WEATHER THREATS FOR THIS AFTERNOON ARE
GUSTY WINDS AND LOW HUMIDITY ACROSS NORTHWESTERN UTAH AND DRY
THUNDERSTORMS ACROSS CENTRAL AND SOUTH CENTRAL UTAH. WINDS HAVE
REACHED CRITICAL LEVELS ACROSS NORTHWEST UTAH...CREATING HAZARDOUS
FIRE WEATHER CONDITIONS. THESE WINDS WILL CONTINUE INTO EARLY
EVENING. SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS EAST
CENTRAL UTAH. THUNDERSTORMS WILL CONTINUE TO INCREASE IN COVERAGE
THROUGH THIS EVENING. STORMS ACROSS SOUTHEASTERN UTAH WILL BE
ACCOMPANIED BY HEAVY RAIN...AS MOISTURE IS QUITE DEEP.
HOWEVER..ACROSS SOUTH CENTRAL AND CENTRAL UTAH...DRY THUNDERSTORMS
ARE EXPECTED DUE TO THE DRY LOWER LEVELS. THOUGH SOME STORMS MAY
BE ACCOMPANIED BY WETTING RAIN...THERE IS CONCERN FOR NEW FIRE
STARTS.

A WEAK...DRY COLD FRONT WILL MOVE INTO NORTHERN UTAH TONIGHT AND
MAKE ITS WAY SOUTHWARD INTO CENTRAL UTAH BY EARLY EVENING. THIS
FRONT WILL SHIFT WINDS TO THE WEST NORTHWEST AND COOL TEMPERATURES
BY A FEW DEGREES. WINDS WILL BE GUSTY ACROSS CENTRAL AND SOUTHERN
UTAH TOMORROW AFTERNOON...BUT AT THIS TIME IT APPEARS THAT WIND
SPEEDS WILL REMAIN JUST BELOW CRITICAL LEVELS. ELEVATED WINDS WILL
CONTINUE INTO FRIDAY AS THE FRONT REMAINS STALLED OVER CENTRAL
UTAH.

HIGH PRESSURE WILL BUILD OVER THE STATE THIS WEEKEND...BRINGING A
WARMING...DRYING TREND AND DECREASING WINDS. MODELS ARE SUGGESTING
THAT MOISTURE WILL MOVE INTO UTAH FROM THE WEST ON
MONDAY...BRINGING THE CHANCE FOR SHOWERS AND THUNDERSTORMS.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...RED FLAG WARNING UNTIL 10 PM MDT THIS EVENING FOR UTZ478-488-489-
     492-493-495-496.

WY...NONE.
&&

$$

PUBLIC...TRAPHAGAN
FIRE WEATHER...HOSENFELD
AVIATION...CHENG

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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