240 FXUS65 KSLC 180955 AFDSLC AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 355 AM MDT THU JUL 18 2013 .SYNOPSIS...HIGH PRESSURE ACROSS THE REGION TODAY WILL SHIFT WEST INTO NEVADA BY FRIDAY...ALLOWING A DRYING TREND FROM NORTH TO SOUTH. MOISTURE WILL BECOME INCREASINGLY CONFINED TO FAR SOUTHERN UTAH OVER THE WEEKEND. && .DISCUSSION...AN ELONGATING MID LEVEL RIDGE REMAINS CENTERED FROM SOUTHERN NV NORTHEASTWARD ACROSS CENTRAL UT. ALONG AND SOUTH OF THIS RIDGE AXIS ABUNDANT MOISTURE REMAINS IN PLACE ACROSS CENTRAL AND SOUTHERN UT...WITH PW VALUES GENERALLY ABOVE AN INCH PER GOES IMAGERY. TO THE NORTH OF THIS AXIS DRIER AIR HAS BEGUN TO INFILTRATE NORTHERN UT...WHERE PW VALUES HAVE BEEN SLOWLY FALLING OVERNIGHT. WITH DAYTIME HEATING WILL SEE ANOTHER ROUND OF CONVECTION THIS AFTERNOON AND EVENING...PRIMARILY ACROSS CENTRAL AND SOUTHERN UT. WITH ABUNDANT MOISTURE AND VERY LIGHT FLOW ALOFT RESULTING FROM THE PROXIMITY OF THE RIDGE AXIS...LOCALLY HEAVY RAIN WILL ONCE AGAIN BE POSSIBLE. CONVECTION SHOULD LARGELY REMAIN ANCHORED ALONG THE HIGHER TERRAIN THROUGH MOST OF THE DAY...BUT MAY BEGIN TO DRIFT SOUTHWARD DURING THE LATE AFTERNOON AND EVENING HOURS. GIVEN THE DOWNBASIN STORM MOTION...MAY SEE A SLIGHTLY ELEVATED FLASH FLOOD RISK OVER PORTIONS OF SOUTHERN UT...HOWEVER HELD OFF ON A FLASH FLOOD WATCH AS CONFIDENCE IS NOT HIGH REGARDING CONVECTIVE EVOLUTION AND COVERAGE. FURTHER NORTH...MAY SEE A BURST OF CONVECTION EARLY IN THE AFTERNOON OVER THE HIGHER TERRAIN...HOWEVER AS THE AIRMASS DRIES OUT ANTICIPATE THIS ACTIVITY TO DIMINISH AS THE DAY PROGRESSES. THE AFOREMENTIONED MID LEVEL RIDGE IS FORECAST TO SLOWLY RETROGRADE INTO NV BY FRIDAY...AND REMAIN FAIRLY STATIONARY OVER THE WEEKEND. AN INCREASINGLY NORTHERLY COMPONENT TO THE FLOW ALOFT WILL CONTINUE TO ADVECT DRIER AIR ACROSS THE FORECAST AREA FROM NORTH TO SOUTH...WITH CONVECTION BECOMING INCREASINGLY CONFINED TO THE SOUTH BEGINNING LATE FRIDAY...AND CONTINUING OVER THE WEEKEND. THIS DRIER AIRMASS SHOULD ALSO ALLOW FOR MORE EFFICIENT DAYTIME MIXING...ALLOWING TEMPERATURES TO APPROACH OR EXCEED THE CENTURY MARK ALONG THE WASATCH FRONT EACH AFTERNOON THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. THE GFS AND EC DIVERGE A BIT NEXT WEEK WITH THE HANDLING OF THE MID LEVEL RIDGE ACROSS THE REGION. THE GFS WANTS TO SHIFT THE RIDGE AXIS BACK TO THE EAST ALLOWING MOISTURE TO RETURN TO NORTHERN UT BY MIDWEEK. THE EC ON THE OTHER HAND DEVELOPS AN ELONGATED EAST-WEST ORIENTED AXIS EARLY NEXT WEEK...WHICH WOULD LIKELY KEEP MOISTURE CONFINED TO THE SOUTH. AS SUCH HAVE LOWERED POPS A BIT IN THE NORTH EARLY NEXT WEEK...DELAYING THE ONSET OF MOISTURE RETURN UNTIL WEDNESDAY. && .AVIATION...THE SLC TERMINAL SHOULD SEE VFR CONDITIONS DURING THE DAY. SOUTHEAST WINDS ARE EXPECTED TO SHIFT TO THE NORTHWEST BETWEEN 18Z AND 20Z. THERE IS A 20 PERCENT CHANCE THAT SHOWERS IN THE VICINITY OF THE TERMINAL WILL RESULT IN PERIODS OF GUSTY AND/OR ERRATIC WINDS THIS AFTERNOON AND EARLY EVENING. && .FIRE WEATHER...HIGH PRESSURE OVER THE REGION WILL SHIFT WEST TODAY...ALLOWING DRIER AIR TO MOVE BACK IN. THE DRYING WILL BEGIN OVER NORTHERN UTAH...BUT WILL SPREAD SOUTHWARD THROUGH THE WEEKEND. SHOWERS AND THUNDERSTORMS ARE EXPECTED EACH AFTERNOON...BUT WILL BE CONFINED FARTHER TO THE SOUTH EACH DAY WITH THE SPREAD OF DRIER AIR. MUCH OF THE DISTRICT WILL SEE QUITE HOT AND DRY CONDITIONS BY SUNDAY...BUT MOISTURE STARTS TO RETURN FROM THE SOUTH BY EARLY NEXT WEEK. WINDS WILL BE LIGHT AND TERRAIN DRIVEN OVER THE NEXT SEVERAL DAYS. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...NONE. WY...NONE. && $$ SEAMAN/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)