Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 152153
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
353 PM MDT TUE APR 15 2014

.SYNOPSIS...A COLD FRONT WILL CROSS UTAH AND SOUTHWEST WYOMING
THIS EVENING AND OVERNIGHT. A WEAK STORM SYSTEM WILL MOVE ACROSS
THE STATE TOMORROW. HIGH PRESSURE WILL REBUILD FOR THE END OF THE
WORK WEEK BEFORE THE NEXT STORM SYSTEM IMPACTS THE AREA FRIDAY
NIGHT AND SATURDAY.



&&

.SHORT TERM (THROUGH 12Z FRIDAY)...PACIFIC NORTHWEST STORM SYSTEM
IS CURRENTLY MOVING ACROSS IDAHO. IT WILL GRAZE NORTHERN UTAH AS
IT CONTINUES EASTWARD TONIGHT. THE ASSOCIATED COLD FRONT HAS MOVED
INTO FAR NORTHWEST UTAH AND WILL CONTINUE ACROSS NORTHERN UTAH
DURING THE EARLY EVENING. IT SHOULD MAKE IT INTO SOUTHERN UTAH
TOMORROW MORNING.

THE VAST MAJORITY OF THE MOISTURE AND INSTABILITY IN ASSOCIATION
WITH THIS TROUGH WILL REMAIN NORTH OF THE AREA AND THE FRONT WILL
BE MOSTLY DRY. LIGHT SHOWERS ARE CURRENTLY BEING OBSERVED NEAR THE
UT/ID BORDER AND THERE REMAINS THE POSSIBILITY FOR SOME SHOWERS
OVER THE HIGHER TERRAIN OF NORTHERN UTAH...BUT ANYTHING THAT
DEVELOPS SHOULD BE GENERALLY LIGHT. THE FRONT WILL HAVE LARGER
IMPACTS ON WINDS AND TEMPERATURES. MAXES ARE CURRENTLY RUNNING IN
EXCESS OF 5F ABOVE SEASONAL NORMS. THE PASSING FRONT IS PROGGED TO
LOWER TEMPERATURES BY ABOUT 10F ACROSS THE STATE...RESULTING IN A
SLIGHTLY COOLER THAN AVERAGE DAY TOMORROW. ADDITIONALLY...GUSTY
WINDS HAVE ALREADY BEEN OBSERVED ALONG AND BEHIND THE FRONT OVER
IDAHO AND NORTHWEST UTAH AND THESE WILL CONTINUE TO SPREAD
SOUTHWARD AS THE FRONT DOES. HOWEVER...WITH MODELS INDICATING 700
MB FLOW AROUND 35 KTS WITH A NOT PARTICULARLY IMPRESSIVE
GRADIENT...OBSERVED WINDS SHOULD NOT MEET ADVISORY CRITERIA AND
WILL NOT ISSUE ANY HEADLINES.

AS THE TROUGH MOVES OUT OF THE AREA ON WEDNESDAY...A SECONDARY
SYSTEM BEHIND IT WILL MOVE ACROSS UTAH. THE WAVE ITSELF LOOKS WEAK
BUT IT IS ACCOMPANIED BY DECENT JET SUPPORT...SO THINK THAT A FEW
SHOWERS WILL DEVELOP OVER THE HIGHER TERRAIN...WIDELY SCATTERED AT
BEST. STRONG HIGH PRESSURE DEVELOPS BEHIND THIS SYSTEM FOR
THURSDAY AND MUCH OF FRIDAY...ALLOWING FOR A QUICK WARMING TREND.

&&

.LONG TERM (AFTER 12Z FRIDAY)...THE GFS AND EC ARE IN FAIR AGREEMENT
THAT THE TROF MOVING INTO THE GREAT BASIN WILL BE BADLY SPLIT AND
THE COLD FRONT SAGGING INTO NRN UT FROM THE NRN BRANCH WAVE WILL BE
QUITE WEAK. THE LOOSELY ORGANIZED SRN BRANCH TROF WILL ALSO BE WEAK
AS IT CROSSES THE SRN CWA FRI AND FRI NIGHT AND WILL MAINLY BRING AN
INCREASE IN MOISTURE AND INSTABILITY TO MOST OF THE CWA. THIS WOULD
GENERATE ISOLATED TO SCATTERED SHOWERS AND A FEW THUNDERSTORMS THAT
COULD LINGER INTO SAT AS THE UPSTREAM RIDGING IS WEAK AND DOES NOT
CLEAR OUT THE MOISTURE VERY FAST.

MODELS START TO DIVERGE AFTER SAT WITH THE GFS FASTER MOVING THE
RIDGE EAST AND INCREASING THE MILD SLY FLOW OVER THE AREA AS SOON AS
SUN. THE EC KEEPS THE RIDGE TO OUR WEST LONGER SO DOESNT WARM THE
AIRMASS AS FAST. NOT MUCH OTHER DIFFERENCE IS EXPECTED IN THE
SENSIBLE WEATHER WITH ONLY A SMALL THREAT OF CONVECTION OVER THE
TERRAIN AND GENERALLY DRY CONDITIONS ELSEWHERE.

THE GFS IS ALSO FASTER WITH THE LARGE PACIFIC TROF APPROACHING THE
WEST COAST EARLY NEXT WEEK AND NOW WANTS TO DEVELOP A DEEP CLOSED
LOW OVER SRN CA BY 12Z TUE THEN MOVES IT SLOWLY E ACROSS THE DESERT
SW THRU WED IMPACTING MAINLY SRN UT BUT SPREADING MOISTURE NORTH BY
LATE WED.

&&

.AVIATION...WINDS AT THE SLC TERMINAL WILL BE PREDOMINANTLY FROM THE
NORTH THROUGH 00Z...THOUGH MAY PERIODICALLY SWITCH TO THE SOUTH WITH
SPEEDS LESS THAN 7 KNOTS. GUSTY NORTHERLY WINDS WILL DEVELOP BETWEEN
00Z AND 01Z. WINDS ARE FORECAST TO REMAIN FROM THE NORTH THROUGH THE
TAF PERIOD...THOUGH THERE IS A 20 PERCENT CHANCE THAT THEY WILL
SWITCH TO THE SOUTHEAST FOR A PERIOD AFTER 10Z. VFR CONDITIONS WILL
PREVAIL.

&&

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

$$

SHORT TERM...TRAPHAGAN
LONG TERM...WILENSKY
AVIATION...HOSENFELD

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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