Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 120152
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
752 PM MDT FRI APR 11 2014

.SYNOPSIS...A MILD WESTERLY FLOW ALOFT WILL PREVAIL THROUGH
TONIGHT. A WEAK SYSTEM WILL CROSS THE REGION SATURDAY. A COLD
UPPER TROUGH WILL DROP SOUTH ACROSS THE AREA SATURDAY NIGHT
THROUGH SUNDAY.

&&

.DISCUSSION...WATER VAPOR LOOP SHOWS A WEAKENING CLOSED LOW
NEARING THE CALIFORNIA COAST...WITH THE NEXT NORTHERN STREAM STORM
OVER BRITISH COLUMBIA. AMDAR 400-250MB WIND OBSERVATIONS REVEAL A
75-110KT NORTHWESTERLY JET FROM BRITISH COLUMBIA INTO THE UPPER
MIDWEST. MEANWHILE A WESTERLY 75-110KT JET EXTENDED FROM SOUTHERN
CALIFORNIA OVER THE SOUTHWEST CONUS. GOES/GPS/RAP/00Z RAOB
INDICATE THE PRECIPITABLE WATER VALUE RANGES BETWEEN 0.14" AND
0.50".

GOING FORECAST IN GOOD SHAPE...JUST A FEW MINOR REFINEMENTS.

MID AND HIGH CLOUDS TO FILL INTO NORTH CENTRAL UTAH OVERNIGHT AS THE
UPPER LEVEL SHEAR AXIS LIFTS SLIGHTLY NORTHWARD. ARIZONA BORDER
REGION MAY SEE A SLIGHT REDUCTION IN CLOUDS DUE TO THIS TRANSLATION.

UPDATED WINDS TO REFINE LOCALLY GUSTY CONDITIONS THIS EVENING...SUCH
AS THE WESTERN UINTA BASIN. ONLY MINOR TWEAKS TO OVERNIGHT
LOWS...AND ADJUSTED HOURLY TEMPERATURE DIURNAL CURVE. REST UNCHANGED.

PREVIOUS DISCUSSION FOLLOWS...

TODAY HAS BEEN ANOTHER WARM AND DRY SPRING DAY ACROSS THE FORECAST
AREA...WITH INCREASING HIGH CLOUD COVER ACROSS THE SOUTHERN HALF OF
UTAH. THIS CLOUD COVER IS OUT AHEAD OF A PACIFIC LOW THAT IS
CURRENTLY OVER THE SOUTHERN CALIFORNIA COAST. AS THE LOW TRACKS
ACROSS THE FOUR CORNERS REGION OVER THE NEXT 24 HOURS...IT WILL HELP
DRAW ADDITIONAL MID-LEVEL MOISTURE INTO THE REGION.

THIS ADDITIONAL MOISTURE SHOULD HELP INITIATE SOME SHOWERS AND
ISOLATED THUNDERSTORMS THROUGH THE DAY TOMORROW...THOUGH DYNAMIC
FORCING REMAINS FAIRLY WEAK. SATURDAY SHOULD ALSO BE A FEW DEGREES
COOLER THAN TODAY ACROSS THE CWA...BOTH DUE TO INCREASED CLOUD COVER
AS WELL AS SOME WEAK COLD ADVECTION IN THE NORTHERN THIRD OF THE
AREA THROUGH THE AFTERNOON.

A STRONGER AND BETTER PUT-TOGETHER STORM SYSTEM WILL DROP INTO THE
AREA LATE SATURDAY THROUGH SUNDAY. THIS WILL BRING A CONSIDERABLY
COLDER AIRMASS INTO UTAH AND SOUTHWEST WYOMING...ESPECIALLY COMPARED
TO MOST OF THE SPRING SO FAR. THIS WILL PRIMARILY PRODUCE MOUNTAIN
SNOWFALL AND VALLEY RAIN...THOUGH THERE IS A CHANCE SNOW LEVELS
COULD BRIEFLY DROP TO THE VALLEY FLOORS OF NORTHERN UTAH THE LATTER
HALF OF SUNDAY. THAT SAID...ANYTHING MORE THAN A DUSTING IS UNLIKELY
ALONG THE WASATCH FRONT.

SHOWERS AND CLOUD COVER LOOK TO DISSIPATE PRETTY QUICKLY ON SUNDAY
NIGHT...WHICH SHOULD LEAD TO A FAIRLY COLD NIGHT. SHORTWAVE RIDGING
BUILDS AGAIN FOR MONDAY...WITH A MODEST WARM-UP TO BEGIN THE WORK
WEEK.

SHORT WAVE RIDGING WILL SHIFT RAPIDLY EAST AND FLATTEN TUESDAY AS A
NEAR WESTERLY FLOW PUNCHES INTO THE WESTERN CONUS FOR THE MIDWEEK
PERIOD. RUN TO RUN CONSISTENCY IN THIS PATTERN EVOLUTION HAS BEEN
WIDELY SPREAD WITHIN THE GFS FOR THE LAST SEVERAL DAYS AND GEFS
MEMBERS REMAIN SO...THOUGH THE 12Z OPERATIONAL HAS BECOME QUITE
CONSISTENT WITH THE COINCIDENT EUROPEAN. ALTHOUGH THE FLOW WILL
REMAIN PROGRESSIVE...THE ONLY SHORT WAVE OF NOTE TO AFFECT THE AREA
IS ADVERTISED TO SLIDE THROUGH MAINLY NORTHERN UTAH TUESDAY
NIGHT/WEDNESDAY BRINGING SOME PRECIP AND A WEAK COLD FRONT. NOTHING
SUBSTANTIAL. UPSTREAM FLOW RESPONSE BECOMES ANTICYCLONIC WITH SUBTLE
RIDGING AND STOUT WARM ADVECTION THEREAFTER FOR THE LATTER HALF OF
THE WEEK. AGAIN...WOULD LIKE TO SEE MORE CONSISTENCY RUN TO RUN AND
MODEL TO MODEL BUT HAVE TRENDED GRIDS IN THAT MANNER.

&&

.AVIATION...OPERATIONAL WEATHER CONCERNS WILL REMAIN MINIMAL AT THE
KSLC TERMINAL THROUGH THE VALID TAF PERIOD. NORTHWEST WINDS WILL
REMAIN IN PLACE THROUGH 03-04Z BEFORE RETURNING TO THE SOUTHEAST.

&&

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

$$

PUBLIC...ROGOWSKI/SCHOENING/MERRILL
AVIATION...KRUSE

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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