Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 212208
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
408 PM MDT THU AUG 21 2014

.SYNOPSIS...THE AIRMASS OVER THE FORECAST AREA WILL SLOWLY DRY
THROUGH FRIDAY...ALTHOUGH CONDITIONS WILL REMAIN UNSETTLED. A
COLD TROUGH WILL MOVE ACROSS NORTHERN UTAH FRIDAY NIGHT AND
SATURDAY.



&&

.DISCUSSION...SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED
ACROSS UTAH AND SOUTHWEST WYOMING THIS AFTERNOON...AS A COUPLE OF
WEAK SHORTWAVES MOVE THROUGH THE AREA. ACROSS THE
SOUTH...ADDITIONAL INSTABILITY IS MOVING INTO THE AREA FROM
ARIZONA...IN ASSOCIATION WITH A CLOSED LOW OVER SOUTHERN
CALIFORNIA. ACROSS THE NORTH...A WAVE CONTINUES TO MOVE ALONG THE
UTAH/IDAHO BORDER...ON THE SOUTH END OF A LARGER TROUGH OVER THE
PACIFIC NORTHWEST. THESE FORCING MECHANISMS SHOULD ALLOW
CONVECTION TO CONTINUE INTO THE EVENING AND POTENTIALLY OVERNIGHT
HOURS...ESPECIALLY IN THE FAR NORTHERN AND FAR SOUTHERN BORDERS OF
THE CWA.

THE PREVIOUSLY MENTIONED TROUGH OVER THE PACIFIC NORTHWEST WILL
BEGIN MOVING INTO THE GREAT BASIN ON FRIDAY. THE ASSOCIATED COLD
FRONT WILL ENTER NORTHERN UTAH ON FRIDAY AFTERNOON...AND THEN
SLIDE THROUGH MOST OF THE CWA FRIDAY EVENING AND SATURDAY MORNING.
THIS TROUGH LOOKS TO BE UNSEASONABLY COLD AND WET...APPEARING MUCH
MORE LIKE A FALL SYSTEM. 700MB TEMPS ARE PROGGED TO DROP AS LOW AS
2 DEGREES CELSIUS ACROSS NORTHERN UTAH BY 12Z SATURDAY...AND
COMBINED WITH PRECIPITATION SHOULD ALLOW FOR NEAR RECORD LOW MAX
TEMPERATURES ACROSS THE NORTHERN HALF OF UTAH ON SATURDAY. HAVE
LOWERED TEMPERATURES AND INCREASED POPS FOR FRIDAY NIGHT THROUGH
SATURDAY...AND POPS WILL LIKELY BE INCREASED FURTHER ON FUTURE
SHIFTS.

PRECIPITATION SHOULD TAPER OFF FAIRLY QUICKLY SATURDAY AFTERNOON
OR EVENING...AS SIGNIFICANTLY DRIER AIR MOVES INTO THE AREA
BEHIND THE TROUGH ON SATURDAY NIGHT. THIS WILL LEAD TO A MOSTLY
DRY AND SOMEWHAT WARMER DAY ON SUNDAY. HOWEVER...THE ACTIVE
PATTERN LOOKS TO CONTINUE FOR THE BEGINNING OF NEXT WORK WEEK...AS
ANOTHER TROUGH MOVES IN FROM THE NORTHWEST ON MONDAY OR MONDAY
NIGHT. DETAILS ON THIS TROUGH ARE STILL UNCERTAIN...AS THE ECMWF
IN PARTICULAR HAD VERY DIFFERENT SOLUTIONS OVER THE PAST FEW RUNS.
THE 12Z EC HAS A FAIRLY SHALLOW TROUGH THAT BRUSHES NORTHERN UTAH
ON MONDAY NIGHT...WHICH IS IN SHARP CONTRAST TO A MUCH DEEPER
TROUGH THAT IT DEVELOPED IN THE 00Z RUN...WHICH BROUGHT WET
WEATHER TO UTAH FOR MONDAY THROUGH WEDNESDAY. IF THE 12Z EC AND
GFS VERIFY...THE CURRENT POPS ARE TOO HIGH IN MUCH OF THE
EXTENDED. HOWEVER...DECIDED TO KEEP SOMEWHAT HIGHER POPS IN PLACE
FOR NOW UNTIL THE MODELS LOCK INTO A SOLUTION FOR THE BEGINNING OF
NEXT WORK WEEK.

&&

.AVIATION...SOUTHEAST WINDS ARE EXPECTED TO PREVAIL THROUGH THE
AFTERNOON AND EVENING AT THE KSLC TERMINAL. THIS SAID...A 20 PERCENT
CHANCE EXISTS THAT OUTFLOW FROM NEIGHBORING SHOWERS WILL CREATE
BRIEF WIND SWITCHES AND ERRATIC GUSTS THROUGH 02Z. VFR CONDITIONS
ARE EXPECTED TO BE MAINTAINED.


&&

.FIRE WEATHER...AN UNSEASONABLY COLD UPPER LOW WILL BRING COOL
UNSETTLED WEATHER TO THE FORECAST AREA BEGINNING TOMORROW EVENING
AND CONTINUING INTO SATURDAY MORNING. MOST OF THE FORECAST
AREA...WITH PERHAPS THE EXCEPTION OF EXTREME SOUTHERN UTAH WILL SEE
WETTING RAIN FRIDAY EVENING THROUGH SATURDAY MORNING. TEMPERATURES
SATURDAY AFTERNOON WILL BE WELL BELOW NORMAL. PRECIPITATION WILL
TAPER OF SATURDAY AFTERNOON. COOL TEMPERATURES WILL CONTINUE INTO
THE WEEKEND. ANOTHER DISTURBANCE WILL CROSS NORTHERN UTAH MONDAY
NIGHT INTO TUESDAY...BRINGING ANOTHER CHANCE FOR
PRECIPITATION...THIS TIME WITH MORE OF A FOCUS ON NORTHERN AND
EASTERN UTAH.

&&

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

$$

PUBLIC...SCHOENING
FIRE WEATHER...HOSENFELD
AVIATION...MERRILL

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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