371 
FXUS65 KSLC 060944
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
345 AM MDT SAT JUL 6 2013

.SYNOPSIS...THE RIDGE OF HIGH PRESSURE OVER THE DESERT SOUTHWEST 
WILL REMAIN TO THE SOUTH AND EAST THROUGH SUNDAY...WITH A MOIST AND 
SOMEWHAT UNSTABLE AIRMASS REMAINING OVER THE EASTERN GREAT BASIN.  
THE RIDGE WILL BUILD NORTHWARD EARLY NEXT WEEK...ENABLING A PUSH OF 
SOMEWHAT DRIER...BUT WARMER...AIR INTO THE REGION. 

&&

.DISCUSSION...A VERY MOIST AIRMASS REMAINS IN PLACE OVER THE 
FORECAST AREA THIS MORNING.  SOME LINGERING CONVECTIVE ACTIVITY WAS 
OVER CENTRAL UTAH AND THE WEST DESERTS.  

ANOTHER ACTIVE WEATHER DAY IS ON TAP FOR TODAY...AS A MOIST 
AIRMASS...WITH PRECIPITABLE WATER VALUES AROUND AN INCH...REMAINS IN 
PLACE.  WHILE A FEW LINGERING SHOWERS AND THUNDERSTORMS CAN BE 
EXPECTED THIS MORNING...BULK OF ACTIVITY WILL BE THIS AFTERNOON AND 
EVENING AS AIRMASS DESTABILIZES.  THOUGH NO OBVIOUS SURFACE SYSTEMS 
WILL BE PRESENT...WEAK DISTURBANCES ROTATING AROUND THE MID LEVEL 
RIDGE WILL ENHANCE CONVECTION...AS WILL SOME UPPER JET 
SUPPORT...OVER NORTHERN SECTIONS.  CONVECTION WILL BE MORE ORGANIZED 
OVER NORTHERN UTAH...WITH SOME POTENTIAL FOR ISOLATED SEVERE 
THUNDERSTORMS...PRIMARILY WIND DAMAGE...AS SHEAR VALUES ACTUALLY A 
BIT HIGHER THAN ON FRIDAY.  FOR SOUTHERN UTAH...THUNDERSTORMS WILL 
BE MORE SCATTERED IN NATURE...WITH LOCALLY HEAVY RAINFALL THE 
PRIMARY THREAT GIVEN MOIST AIRMASS AND VERY SLOW NET STORM MOTION.
WHILE CONVECTION WILL LINGER INTO THE EVENING HOURS...EXPECT LESS 
NOCTURNAL CONVECTION SATURDAY NIGHT GIVEN LESS ATMOSPHERIC FORCING.

SOME DRIER AIR WILL FILTER INTO SOUTHWEST UTAH ON SUNDAY...SO 
COVERAGE WILL BE A BIT LESS THAN TODAY...BUT STILL EXPECT A FAIR 
AMOUNT OF ACTIVITY.  

FROM MONDAY AND TUESDAY...MODELS INDICATE RIDGE WILL BUILD OVER 
REGION...WITH A DRIER WESTERLY FLOW DEVELOPING...SO AREAL COVERAGE 
OF SHOWERS AND STORMS WILL DECREASE EACH DAY.  

ON WEDNESDAY...JUST ENOUGH MOISTURE WILL BE LEFT FOR SOME HIGH 
TERRAIN CONVECTIVE ACTIVITY.

FOR THURSDAY THROUGH SATURDAY...GFS AND ECMWF SOLUTIONS DIVERGE A 
BIT WITH ECMWF ELONGATING RIDGE AND INDICATING LESS MOISTURE 
ADVECTING NORTHWARD INTO FORECAST AREA THAN GFS...WHICH CENTERS 
RIDGE OVER COLORADO.  EVEN WITH GFS SOLUTION...ONLY FAR SOUTHERN 
UTAH WILL BE IMPACTED ON THURSDAY.  FOR FRIDAY AND SATURDAY...HAVE 
SLIGHT CHANCE TO CHANCE WORDING MANY LOCATIONS.

&&
 
.AVIATION...SOUTH WINDS WILL PREVAIL AT THE SALT LAKE TERMINAL 
THROUGH THE MORNING HOURS. EXPECTING A WIND SHIFT TO THE NORTHWEST 
AROUND 19-20Z...BUT THERE IS A 30 PERCENT CHANCE THAT THIS SHIFT 
WILL NOT OCCUR. RATHER...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO 
DEVELOP ACROSS NORTHERN UTAH DURING THE AFTERNOON HOURS WITH OUTFLOW 
WINDS POSSIBLY CONTRIBUTING TO ERRATIC WIND DIRECTIONS AND 
OCCASIONAL GUSTS GREATER THAN 26KT. VFR CONDITIONS ARE EXPECTED 
THROUGH THE DAY SATURDAY BUT CIGS NEAR/BELOW 6000FT AGL WILL BE 
POSSIBLE UNDER HEAVIER SHOWERS. THERE IS A 20 PERCENT CHANCE OF 
THUNDERSTORMS WITHIN 5SM OF THE TERMINAL...WITH BEST WINDOW BETWEEN 
20-02Z.

&&

.FIRE WEATHER...A MOIST AND UNSTABLE AIRMASS WILL REMAIN IN PLACE 
THROUGH THE WEEKEND. THIS WILL CONTINUE TO BRING PERIODS OF WET 
THUNDERSTORMS TO MUCH OF THE FIRE DISTRICT...ALTHOUGH GUSTY OUTFLOW 
WINDS WILL ACCOMPANY SOME OF THE STRONGER STORMS. A DRYING TREND 
WILL BEGIN ON MONDAY AND CONTINUE THROUGH MIDWEEK. AS RELATIVE 
HUMIDITIES LOWER...CRITICAL FIRE WEATHER CONDITIONS MAY DEVELOP AS 
SOUTHERLY WINDS INCREASE...ESPECIALLY ON WEDNESDAY AND THURSDAY. 
OTHERWISE...MOISTURE LOOKS TO SPREAD BACK INTO THE AREA AGAIN FOR 
THE END OF NEXT WEEK.

&&

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

&&

$$

AVIATION...CHENG
FIRE WEATHER...CHENG
PUBLIC...BARJENBRUCH

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)