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000
FXUS65 KSLC 151644
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1044 AM MDT WED MAY 15 2013

.SYNOPSIS...A WEAK UPPER LEVEL DISTURBANCE WILL MOVE EAST ACROSS
SOUTHERN UTAH TODAY. BEHIND THIS SYSTEM A STRONGER TROUGH WILL
MOVE INTO THE GREAT BASIN LATE IN THE WEEK...FOLLOWED BY A STILL
COLDER SYSTEM OVER THE WEEKEND.


&&

.DISCUSSION...THE UPPER LEVEL DISTURBANCE THAT HAS MOVED INTO
SOUTHWEST UTAH THIS MORNING IS WELL DEFINED ON WATER VAPOR
IMAGERY. SO FAR...THOUGH...IT HAS ONLY BEEN ACCOMPANIED BY A BIT
OF CLOUD COVER TO ITS NORTH AND EAST. THIS SYSTEM WILL TRACK
ACROSS SOUTHERN UTAH THROUGH THIS EVENING...BRINGING A BIT OF
INSTABILITY AS IT PASSES. HOWEVER...LACK OF MOISTURE SHOULD KEEP
ANY AFTERNOON CONVECTIVE ACTIVITY ISOLATED AT BEST. THE SYSTEM MAY
ACT TO HELP NUDGE NORTHWARD THE STALLED BOUNDARY CURRENTLY NEAR A
KELY-KPVU-KRKS LINE...LIKELY BACK UP TO NEAR THE GSL.

BEHIND THE EXITING DISTURBANCE...SOUTHWEST FLOW WILL INCREASE
THURSDAY AHEAD OF A SERIES OF APPROACHING STORM SYSTEMS THAT WILL
IMPACT THE FORECAST AREA FRIDAY THROUGH THE WEEKEND. THIS COULD
PRODUCE SOME BREEZY WINDS IN AREAS WITH LOW RELATIVE
HUMIDITY...PARTICULARLY OVER SOUTHERN UTAH. INITIAL FRONTAL
BOUNDARY IN ASSOCIATION WITH THE FIRST SYSTEM WILL CROSS MUCH OF
THE FORECAST AREA THURSDAY NIGHT INTO FRIDAY. THE SYSTEM IS
GENERALLY LACKING IN MOISTURE BUT THERE IS A DECENT PROBABILITY OF
CONVECTION...PARTICULARLY ALONG THE FRONT. TEMPS WILL BE NOTICEABLY
COOLER BY SATURDAY...WITH MAXES RUNNING NEAR TO A FEW DEGREES
BELOW SEASONAL NORMS...AS OPPOSED TO THE NEAR RECORD TEMPERATURES
OBSERVED THE PAST FEW DAYS.


THE FIRST SYSTEM EXITS BEGINNING SATURDAY MORNING...BUT A SECOND
PACIFIC NORTHWEST TROUGH FOLLOWS QUICKLY ON ITS HEELS...BRINGING A
REENFORCING SHOT OF COOLER AIR. ECMWF BRINGS MORE INSTABILITY WITH
THIS SYSTEM THAN THE GFS...AS THE GFS KEEPS THE COLD POOL MOSTLY
TO THE EAST OF THE AREA. IN THE ECMWF...THE 500 MB COLD AIR MOVES
OVER THE STATE. REGARDLESS...THE UNSTABLE AIRMASS LOOKS TO PERSIST
THROUGH THE EARLY PART OF NEXT WEEK BEFORE HIGH PRESSURE MOVES
BACK IN.

NO UPDATES EXPECTED TO THE FORECAST THIS MORNING.



&&

.AVIATION...THE SLC TERMINAL WILL SEE VFR CONDITIONS THROUGHOUT
THE DAY WITH SOME SCATTERED CLOUDS. LIGHT WINDS ARE EXPECTED TO
BECOME PREVAILING NORTHWESTERLY BY 18Z.

&&

.FIRE WEATHER...A WEAK TROUGH WILL MOVE ACROSS THE AREA TODAY
PROMOTING A SLIGHT CHANCE OF THUNDERSTORMS ACROSS MAINLY CENTRAL AND
NORTHERN UTAH MOUNTAINS. SOUTHWEST WINDS WILL BE MODERATE STRONG
OVER THE EXTREME SOUTHWEST...SOUTH CENTRAL AND EASTERN VALLEYS THIS
AFTERNOON.

A STRONGER SYSTEM WILL APPROACH ON THURSDAY BRINGING STRONGER
SOUTHWESTERLY WINDS ACROSS MOST OF THE REGION. CRITICAL
METEOROLOGICAL FIRE WEATHER CONDITIONS FOR GUSTY WINDS AND LOW RH
WILL COVER MUCH OF SOUTHERN UTAH THURSDAY AND FRIDAY...BUT WITH
FUELS REMAINING BELOW CRITICAL LEVELS NO RFWS WILL BE ISSUED AT THIS
TIME.

&&

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

$$

PUBLIC/AVIATION...TRAPHAGAN
FIRE WEATHER...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)