Weather Service Report


940 
FXUS65 KSLC 301003
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
403 AM MDT THU JUL 30 2015

.SYNOPSIS...A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE REGION
THROUGH THE END OF THE WEEK...THEN SHIFT EASTWARD EARLY NEXT WEEK. 
MOISTURE WILL SLOWLY INCREASE ACROSS SOUTHERN UTAH TODAY AND
FRIDAY...THEN SPREAD SLOWLY NORTHWARD LATE IN THE WEEKEND.

&&

.SHORT TERM (THROUGH 00Z SUNDAY)...THE RIDGE AXIS REMAINS IN PLACE ACROSS 
CENTRAL UTAH STRETCHING FROM THE SOUTHERN PLAINS TO NORTHERN 
CALIFORNIA. TO THE NORTH OF THIS AXIS THE AIR MASS REMAINS VERY DRY 
WHILE TO THE SOUTH THERE HAS BEEN A LITTLE INCREASE IN MID TO HIGH 
LEVEL MOISTURE. DESPITE PWS COMING UP ACROSS EXTREME SOUTHERN UTAH 
TODAY AND FRIDAY...FORECAST SOUNDINGS SHOW THAT THIS INCREASE IS DUE 
PRIMARILY TO MOISTURE ALOFT ABOVE 400MB. THERE IS A WEAK DISTURBANCE 
THAT MOVES NORTHWARD FROM ARIZONA TOWARDS THE UTAH BORDER BY LATE 
TODAY AND INTO EXTREME SOUTHERN UTAH NEAR LAKE POWELL BY FRIDAY SO 
KEPT SOME MEAGER POPS THERE. OTHERWISE...LOW LEVELS REMAIN RATHER 
DRY AS NORTHERLY FLOW REMAINS IN PLACE BELOW ABOUT 600MB 
...THEREFORE HAVE LOWERED POPS FROM ABOUT GARFIELD COUNTY NORTH AND 
WEST. WHAT LITTLE CONVECTIVE ACTIVITY THAT DOES FORM TODAY AND FOR 
THAT MATTER FRIDAY WILL LIKELY BE OF THE HIGH-BASED VARIETY
THUNDERSTORMS WITH LITTLE IF ANY RAIN BUT INSTEAD GUSTY WINDS.

TEMPERATURES ACROSS THE NORTHERN PORTIONS OF THE CWA SHOULD WARM 
ANOTHER SEVERAL DEGREES TODAY AS THE 850MB TEMPS WARM 2-3 DEGREES 
CELSIUS AND THE 700MB TEMPS WARM ABOUT 2 DEGREES CELSIUS. ACROSS THE 
SOUTH THE TEMPERATURES WILL BE QUITE SIMILAR TO YESTERDAY WITH MOST 
PLACES WITHIN A DEGREE OR TWO. SOME PLACES MAY BE A LITTLE COOLER 
ESPECIALLY NEAR THE ARIZONA BORDER WHERE EXTRA CLOUD COVER COULD 
INHIBIT STRONG WARMING.
 
SATURDAY THE MOISTURE INCHES A LITTLE FARTHER NORTH BUT STILL NOT 
IMPRESSED AS NORTHERLY WINDS WILL REMAIN BELOW 600MB ACROSS MOST OF 
THE CWA. TEMPERATURES AT 700MB PEAK ACROSS NORTHERN UTAH BUT WILL 
REMAIN STABLE ACROSS THE SOUTH. 

.LONG TERM (AFTER 00Z SUNDAY)...GFS AND ECMWF IN GOOD AGREEMENT
EARLY IN PERIOD...WITH UPPER RIDGE AXIS CENTERED OVER FORECAST
AREA...BUT THEN MODEL SOLUTIONS DIVERGE. GFS SHIFTS RIDGE AXIS
EASTWARD...ALLOWING MID LEVEL FLOW TO TURN SOUTHWESTERLY...
FACILITATING A NORTHWARD PUSH OF MOISTURE THROUGH MONDAY...THOUGH
LOWER LEVELS OF ATMOSPHERE REMAIN RATHER DRY. ECMWF ELONGATES
RIDGE TO SOUTH OF FORECAST AREA EARLY NEXT WEEK...PROMOTING A
MORE WESTERLY...DRIER FLOW. ECMWF DOES SEEM TO BE ERRATIC...LOCKING
ON TO CONVECTIVE COMPLEXES AND DEEPENING THEM WITH TIME. GIVEN
LITTLE SPREAD IN GFS ENSEMBLE SOLUTIONS...THAT ARE GENERALLY IN
LINE WITH DETERMINISTIC GFS...WILL GO WITH GFS SOLUTION.
THUS...WILL KEEP EXISTING SLIGHT CHANCE WORDING FOR MUCH OF
FORECAST AREA SUNDAY AND MONDAY. WITH PRECIPITABLE WATER VALUES
REMAINING AT OR BELOW THREE QUARTERS OF AN INCH AND RELATIVELY DRY
LOWER LEVELS...DO NOT SEE MUCH OF A FLASH FLOOD THREAT DURING
PERIOD.

WITH GFS INDICATING SOME DRIER AIR WORKING INTO NORTHERN AND
WESTERN PORTIONS OF FORECAST AREA TUESDAY AND WEDNESDAY...WILL
INDICATE LESS COVERAGE OVER NORTHWEST HALF OF UTAH.

&&

.AVIATION...LIGHT SOUTHEAST WINDS AT SLC TERMINAL WILL SHIFT TO 
NORTHWEST BETWEEN 15 AND 16Z THIS MORNING WITH A 40 PERCENT CHANCE 
OF HOLDING OFF UNTIL 17Z. NO OTHER WEATHER CONCERNS THROUGH THE TAF 
PERIOD.

&&

.FIRE WEATHER...THE MAIN FIRE WEATHER CONCERN OVER THE NEXT FEW DAYS 
WILL BE THE POTENTIAL FOR DRY LIGHTNING. FORECAST SOUNDINGS SHOW 
THAT THE INCREASING MOISTURE WILL BE UPSTAIRS AND THAT THE LOWER
LEVELS REMAIN RATHER DRY. THERE IS NO CLEAR CUT ORGANIZED SYSTEM
OTHER THAN A WEAK DISTURBANCE THAT SKIRTS THE SOUTHERN ZONES
FRIDAY AFTERNOON TO GET AN AREA OF ORGANIZED CONVECTION...SO FOR
THE TIME BEING EXPECT DRY THUNDERSTORMS TO BE GENERALLY ISOLATED
THROUGH THE WEEKEND. THE MOST WIDESPREAD ACTIVITY...ACROSS THE
ENTIRE CWA...IS EXPECTED TO BE SUNDAY AND MONDAY WITH A DRYING
TREND SETTING IN TUESDAY. ALONG WITH DRYING...WINDS WILL INCREASE
OVER WESTERN VALLEYS TUESDAY AND THEN BECOME STRONGER AND MORE
WIDESPREAD WEDNESDAY AND THURSDAY. DEPENDING ON THE FUELS STATUS
BY THEN ANY HOLD OVER LIGHTNING STRIKE STARTS MAY HAVE AN
OPPORTUNITY TO SPREAD.

&&

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

&&

$$

PUBLIC...BARJENBRUCH/STRUTHWOLF
AVIATION...STRUTHWOLF
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)

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