Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 300955
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
355 AM MDT SUN AUG 30 2015

.SYNOPSIS...A COLD FRONT WILL SLIDE SOUTHEAST INTO CENTRAL UTAH BY
EARLY AFTERNOON...THEN STALL OUT...BEFORE EVENTUALLY ERODING
TONIGHT. WITH THE REGION BETWEEN A RIDGE OF HIGH PRESSURE FROM THE
UPPER MIDWEST TO THE SOUTHERN PLAINS AND A TROUGH OF LOW PRESSURE
OVER THE PACIFIC NORTHWEST...A GENERALLY DRY SOUTHWEST FLOW WILL
PREVAIL FOR MOST OF THE WORKWEEK.

&&

.SHORT TERM (THROUGH 12Z WEDNESDAY)...MUCH OF UTAH AND SOUTHWEST
WYOMING REMAINS IN THE WARM SECTOR OUT AHEAD OF A LARGE TROUGH
MOVING THROUGH THE PACIFIC NORTHWEST EARLY THIS MORNING. A SHALLOW
ASSOCIATED COLD FRONT HAS PUSHED INTO NORTHWEST UTAH OVERNIGHT...AND
SHOWERS AND THUNDERSTORMS HAVE BEEN INITIATING NEAR THIS LOW LEVEL
BAROCLINIC ZONE THROUGH MUCH OF THE NIGHT. THIS FRONT WILL GENERALLY
TEND TO WEAKEN AND DISSIPATE AS IT MOVES INTO CENTRAL AND EASTERN
UTAH THROUGH THE DAY...BUT NOT BEFORE INCREASED SHOWER ACTIVITY
FORMS ACROSS THE EASTERN HALF OF UTAH...WHERE THE BEST MOISTURE TAP
COLLIDES WITH THE SYNOPTIC SCALE FORCING.

TODAY SHOULD ALSO GENERALLY BE COOLER THAN YESTERDAY...WITH COLD AIR
ADVECTION ACROSS THE NORTH...AND INCREASING CLOUD COVER ACROSS THE
SOUTH AND EAST. THAT SAID...SOME OF THIS COOLING MAY BE MITIGATED BY
THE WARM STARTING TEMPERATURES THIS MORNING.

THE PARENT SHORTWAVE IS EXPECTED TO EJECT INTO THE NORTHERN GREAT
PLAINS TONIGHT AND MONDAY...WITH A DRIER AND MORE STABLE AIR MASS PUSHING
INTO THE GREAT BASIN BEHIND THE WAVE. MONDAY SHOULD BRING SEASONAL
TEMPERATURES TO MUCH OF THE CWA...WITH ENOUGH LINGERING MOISTURE
THAT ISOLATED STORMS COULD FORM OVER THE HIGHER TERRAIN. A WARMER
AND DRIER SOUTHWESTERLY FLOW INCREASES OVER THE REGION ON TUESDAY
INTO WEDNESDAY...AS THE NEXT TROUGH BEGINS TO DROP INTO THE
PACIFIC NORTHWEST.

.LONG TERM (AFTER 12Z WEDNESDAY)...GFS AND ECMWF IN GENERAL
AGREEMENT WITH SLOWLY DEEPENING PACIFIC NORTHWEST TROUGH WEDNESDAY
AND THURSDAY...WHILE SHIFTING RIDGE OF HIGH PRESSURE FROM THE
MIDWEST TO THE SOUTHERN PLACES EASTWARD. LOCATED BETWEEN THESE
SYSTEMS...THE GREAT BASIN WILL EXPERIENCE A DRY SOUTHWEST FLOW
WEDNESDAY AND THURSDAY.

THE TROUGH OF LOW PRESSURE WILL MOVE EASTWARD FRIDAY AND
SATURDAY...GLIDING ACROSS THE NORTHERN ROCKIES AND NORTHERN
REACHES OF THE GREAT BASIN. GFS AND ECMWF DIVERGE A BIT DURING
PERIOD...WITH ECMWF OFFERING A SLOWER SOLUTION. ENSEMBLE RUNS
INDICATE A FAIR AMOUNT OF SPREAD WITH SOLUTIONS...SO DEFINITELY
SOME UNCERTAINTY WITH RESPECT TO TIMING. IT APPEARS COLD FRONT
ASSOCIATED WITH TROUGH SHOULD DROP INTO FORECAST AREA FRIDAY
AFTERNOON OR NIGHT. MOISTURE DEFINITELY LIMITED WITH SYSTEM WITH
PRECIPITABLE WATER VALUES ONLY AROUND A HALF AN INCH. WITH SOME
LIFT FROM UPPER TROUGH AND COLD FRONT...WILL ADD A SLIGHT CHANCE
FOR SHOWERS AND THUNDERSTORMS FAR NORTHERN UTAH FOR FRIDAY
AFTERNOON AND EVENING. SHOULD SEE COOL ENOUGH AIR ALOFT TO COOL
DAYTIME HIGHS BY 5 TO 10 DEGREES FOR SATURDAY.

HIGH PRESSURE RIDGE WILL START TO BUILD OVER REGION ON
SUNDAY...SUGGESTING DRY WEATHER ONCE AGAIN...THOUGH TEMPERATURES
WILL REMAIN A FEW DEGREES BELOW NORMAL.

&&

.AVIATION...THE BIGGEST WEATHER UNCERTAINTY AT THE SLC TERMINAL THIS
MORNING IS THE SURFACE WIND FORECAST WITH A WEAK APPROACHING COLD
FRONT. THE MOST LIKELY SCENARIO IS FOR WINDS TO SWITCH TO THE WEST
OR NORTHWEST BETWEEN 10Z AND 12Z...PERHAPS EVEN BRIEFLY GUSTY...WITH
WINDS REMAINING NORTHWEST FOR THE REST OF THE DAY. HOWEVER...THERE
IS A SLIGHT CHANCE THAT SOUTHERLY OR LIGHT AND VARIABLE WINDS COULD
CONTINUE THROUGH PARTS OF THE MORNING...WITH STEADY NORTHWESTERLIES
WAITING UNTIL 18Z TO BECOME BETTER ESTABLISHED. THERE IS ALSO A 20
PERCENT CHANCE OF SHOWERS AND THUNDERSTORMS AT THE TERMINAL THROUGH
00Z MONDAY.

&&

.FIRE WEATHER...A COLD FRONT IS PUSHING THROUGH NORTHERN UTAH THIS
MORNING...AND WILL CONTINUE TO PUSH THROUGH THE REGION THROUGH THE
DAY. THIS FRONT WILL HELP PRODUCE GUSTY WINDS ACROSS MUCH OF THE
STATE. SHOWER AND THUNDERSTORM ACTIVITY IS PRIMARILY ACROSS NORTHERN
UTAH EARLY THIS MORNING...BUT SHOULD SPREAD INTO SOUTHERN AND
EASTERN UTAH IN THE LATE MORNING AND AFTERNOON HOURS...WITH THE
FOCUS ALONG THE SPINE OF UTAH AND EASTWARD THIS AFTERNOON AND
EVENING.

AFTER THIS WAVE PASSES...DRIER AIR IS EXPECTED TO MOVE INTO THE AREA
MONDAY AND TUESDAY. WINDS WILL GENERALLY BE LIGHTER ON MONDAY...BUT
WILL PICK UP AGAIN FROM THE SOUTHWEST STARTING ON TUESDAY. WITH
WINDS INCREASING AND MOISTURE DECREASING THROUGH MIDWEEK...CRITICAL
CONDITIONS MAY BE POSSIBLE TUESDAY THROUGH FRIDAY...PARTICULARLY
ACROSS WESTERN UTAH.

&&

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

&&

$$

PUBLIC...SCHOENING/BARJENBRUCH
AVIATION...SCHOENING
FIRE WEATHER...SCHOENING

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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