Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 252046
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
246 PM MDT SAT JUL 25 2015

.SYNOPSIS...A DRY SOUTHWESTERLY FLOW ALOFT WILL PREVAIL ACROSS THE
REGION THROUGH THE WEEKEND. A DRY COLD FRONT WILL CROSS THE AREA ON
MONDAY...BRINGING MUCH COOLER TEMPERATURES TO NORTHERN AND CENTRAL
UTAH THROUGH TUESDAY. HIGH PRESSURE WILL FOLLOW FOR THE LATTER
HALF OF THE WEEK WITH MOISTURE POTENTIALLY RETURNING LATE IN THE
WEEK.

&&

.SHORT TERM (THROUGH 18Z WEDNESDAY)...SOUTHWESTERLY FLOW ALOFT
PREVAILS ACROSS THE REGION THIS AFTERNOON...WHICH HAS ADVECTED A
VERY DRY AIRMASS INTO SOUTHERN AND CENTRAL UT. LINGERING MOISTURE
ACROSS THE NORTH IS SUPPORTING HIGH BASED CU...HOWEVER UP TO THIS
POINT VERTICAL DEVELOPMENT HAS BEEN STUNTED BY WARMING 500MB
TEMPERATURES. HAVE MAINTAINED A DRY FORECAST THIS EVENING ACROSS
THE NORTH ALTHOUGH AN ISOLATED HIGH BASED STORM CANT BE RULED OUT
OVER THE RAFT RIVERS AND/OR UINTAS.

A MID LEVEL TROUGH CURRENTLY ALONG THE WEST COAST IS FORECAST TO
AMPLIFY SUNDAY...BACKING THE DOWNSTREAM FLOW ACROSS THE FORECAST
AREA. THIS WILL HELP SHIFT THE 700MB THERMAL RIDGE IN PLACE ACROSS
CENTRAL AND SOUTHERN UT NORTHWARD...RESULTING IN A WARMING TREND
ACROSS NORTHERN UT WITH HIGHS PUSHING THE UPPER 90S ALONG THE
WASATCH FRONT. AT THE SAME TIME THIS BACKED FLOW WILL HELP PULL
MOISTURE IN PLACE ACROSS EASTERN AZ NORTHWARD INTO THE FOUR
CORNERS REGION. ALTHOUGH THE BULK OF THIS MOISTURE WILL REMAIN
EAST OF THE FORECAST AREA...MAY SEE HIGH BASED CONVECTION OVER THE
HIGHER TERRAIN IN THE SOUTHEAST INCLUDING THE HENRIES AND BOULDER
MOUNTAIN...POTENTIALLY SPREADING NORTHWARD INTO THE UINTAS AND
WASATCH PLATEAU LATE IN THE DAY.

THE PACIFIC COAST TROUGH IS FORECAST TO SWING INLAND SUNDAY
NIGHT...PUSHING A COLD FRONT THROUGH NORTHERN AND CENTRAL UTAH ON
MONDAY. ALTHOUGH THE BEST UPPER SUPPORT AND MOISTURE WILL REMAIN
NORTH OF THE ID BORDER...THE GFS DOES SUGGEST A WINDOW OF
FAVORABLE DYNAMIC LIFT ACROSS FAR NORTHERN UT MONDAY
MORNING WHICH COULD SUPPORT ISOLATED SHOWERS. FOR NOW HAVE LEFT A
MENTION OUT OF THE VALLEYS BUT INCLUDED A SLIGHT CHANCE OVER THE
HIGHER TERRAIN. IN THE WAKE OF THIS FRONT A MUCH COOLER AIRMASS
WILL SPREAD INTO NORTHERN UT TUESDAY...WITH TEMPERATURES LIKELY
REMAINING CONFINED TO THE 70S ACROSS THE NORTHERN VALLEYS.

.LONG TERM (AFTER 18Z WED)...THE E-W ORIENTED HIGH WILL CONTINUE TO
BUILD OVER THE AREA WED AFTN INTO THU WITH CONTINUED WARMING TEMPS.
THE HIGH SHIFTS INTO WRN CO THU AFTN ALLOWING MOISTURE POOLED SOUTH
OF THE RIDGE AXIS TO START SEEPING INTO SRN UT.

THE HIGH SHIFTS IN RESPONSE TO A SHORT WAVE IN THE MODELS MOVING UP
FROM TROPICAL OLD MEXICO LIFTING NWD THRU CA WED THRU THU. THE ERN
END OF THIS WAVE STARTS TO MOVE INTO SRN UT FRI AND ROTATES NWD THE
EWD THRU THE CWA FRI AFTN THRU SAT. THIS...IF CORRECT...BRINGS A
SIGNIFICANT INCREASE IN MOISTURE TO THE REGION AND A CORRESPONDING
INCREASE IN CONVECTION AND DECREASE IN TEMPS.

THE CURRENT RUNS OF THE EC AND GFS ARE IN FAIR AGREEMENT ON THIS
SCENARIO AND KEEP MOISTURE IN PLACE ONCE THE WAVE PASSES ON SUN.
SO HAVE RAISED POPS A BIT STARTING THU AND EXPECT THEY WILL NEED
TO GO UP MORE IF MODELS STICK WITH THIS IDEA AND CONFIDENCE
INCREASES.

&&

.AVIATION...NORTHERLY WINDS WILL CONTINUE AT THE SLC TERMINAL INTO
THIS EVENING. EXPECT WINDS TO SHIFT TO SOUTHEASTERLY BETWEEN
03-04Z.

&&

.FIRE WEATHER...SOUTHWESTERLY FLOW ALOFT WILL STRENGTHEN A BIT
SUNDAY...WHICH MAY RESULT IN SPOTTY CRITICAL FIRE WEATHER
CONDITIONS WHERE FUELS ARE DRY ACROSS PORTIONS OF SOUTHWEST
UTAH. A LIMITED AMOUNT OF MOISTURE WILL SPREAD INTO THE EASTERN
PORTIONS OF THE AREA SUNDAY AFTERNOON BRINGING A SMALL THREAT
FOR HIGH BASED CONVECTION. A COLD FRONT WILL SWEEP ACROSS THE
AREA DURING THE DAY MONDAY BRINGING MUCH COOLER TEMPERATURES TO
NORTHERN AND CENTRAL UTAH. AHEAD OF THIS FRONT GUSTY SOUTHWEST
WINDS WILL DEVELOP ACROSS SOUTH CENTRAL AND EAST CENTRAL
UTAH...WHERE HUMIDITY VALUES WILL LIKELY FALL INTO THE SINGLE
DIGITS. HIGH PRESSURE IS EXPECTED TO REDEVELOP DURING THE
MIDDLE TO LATTER PORTION OF NEXT WEEK ALLOWING FOR A WARMING
TREND...WITH MOISTURE POTENTIALLY RETURNING LATE IN THE WEEK.

&&

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

$$

SEAMAN/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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