Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 222215
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
415 PM MDT MON SEP 22 2014

.SYNOPSIS...AN UPPER LOW WILL CONTINUE TO EXIT THE AREA THIS
EVENING. HIGH PRESSURE WILL FOLLOW FOR MIDWEEK. ANOTHER STORM
SYSTEM WILL MOVE INTO THE REGION FOR THE WEEKEND.

&&

.DISCUSSION...A FEW SHOWERS AND A STRAY THUNDERSTORM OR TWO HAVE
DEVELOPED MAINLY ALONG THE UTAH/IDAHO BORDER AND EAST OF THE
WASATCH MOUNTAINS THIS AFTERNOON. THE THREAT WILL CONTINUE TO
DECREASE AS MID-LEVEL WARMING CONTINUES IN THE WAKE OF THE UPPER
LEVEL LOW ACROSS NORTHERN UTAH.

HIGH PRESSURE WILL BUILD INTO THE AREA FOR THE FIRST FULL DAY OF
THE FALL SEASON...WITH TEMPERATURES WARMING TO WELL ABOVE NORMAL
LEVELS BY WEDNESDAY AS HIGH PRESSURE FURTHER AMPLIFIES. IT IS
EVEN POSSIBLE A FEW LOCATIONS ACROSS NORTHERN UTAH MAY REACH THE
90S BY WEDNESDAY OR THURSDAY.

ENHANCED MOISTURE MAY ADVECT INTO THE AREA AHEAD OF A LARGE
PACIFIC TROUGH FROM THE REMNANTS OF POST TROPICAL CYCLONE POLO
THURSDAY AFTERNOON INTO THURSDAY EVENING. SLIGHTLY INCREASED POPS
ACROSS SOUTHWESTERN UTAH IN RESPONSE BUT THIS IS A CHANGE FROM
NEARLY ZERO TO AROUND 10 PERCENT. THIS MAY NEED TO BE INCREASE
FURTHER DEPENDING ON FUTURE MODEL RUNS.

DIFFERENCES BEGIN TO EMERGE IN THE 12Z MODELS AS THE DEEPENING
TROUGH OFF THE PACIFIC COAST CONTINUES TO MOVE EASTWARD FRIDAY
INTO SATURDAY. THE GFS WAS STRONGER AND MORE PROGRESSIVE WITH THIS
TROUGH AS IT MOVES ACROSS THE WESTERN UNITED STATES THAN THE EC.
SO WHILE THE DETAILS VARY BETWEEN THE MODELS...BOTH THE 12Z GFS
AND THE 12Z EC INDICATE A PERIOD OF WIDESPREAD PRECIPITATION IS
LIKELY FOR MUCH OF THE CWA SATURDAY INTO SUNDAY. STARTED
INCREASING POPS DURING THIS PERIOD...THOUGH TIMING MAY VARY A BIT
AS MODELS BEGIN TO COALESCE INTO A MORE CONSISTENT SOLUTION.
EITHER WAY...THIS WEEKEND LOOKS WET AND MUCH COOLER.

&&

.AVIATION...THERE IS A 10 PERCENT CHANCE OF PASSING RAIN SHOWERS
LOWERING CEILINGS BELOW 7000 FT AND CREATING PERIODS OF GUSTY AND
ERRATIC WINDS UNTIL ABOUT 00Z.

&&

.FIRE WEATHER...LINGERING MOISTURE WILL CONTINUE TO SUPPORT
ISOLATED SHOWERS AND THUNDERSTORMS ACROSS THE NORTH AND
EAST...DECAYING FOR GOOD THIS EVENING. LIGHTNING IS THE PRIMARY
THREAT.

MEANWHILE...A WARMING AND DRYING TREND THAT BEGAN TODAY ACROSS THE
SOUTHWEST AND BE IN PLACE ACROSS THE ENTIRE REGION THROUGH MID WEEK
AS A RIDGE OF HIGH PRESSURE AMPLIFIES OVERHEAD.

THERE REMAINS CONSIDERABLE UNCERTAINTY REGARDING THE TIMING OF A
COLD FRONT LATE IN THE WEEK. CRITICAL FIRE WEATHER CONDITIONS WILL
BE POSSIBLE AHEAD OF THE COLD FRONT WITH STRONG GUSTY SOUTH WINDS
DEVELOPING...BEFORE CONVECTIVE CHANCES ONCE AGAIN INCREASE NEXT
WEEKEND.

&&

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

$$

KRUSE/ROGOWSKI/VERZELLA

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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