Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 221047
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
447 AM MDT MON SEP 22 2014

.SYNOPSIS...AN UPPER LOW WILL CONTINUE TO CROSS NORTHERN UTAH TODAY
BEFORE EXITING THE AREA. HIGH PRESSURE WILL FOLLOW FOR MID
WEEK...BEFORE ANOTHER STORM SYSTEM MOVES INTO THE REGION FOR THE
WEEKEND.

&&

.DISCUSSION...AN UPPER LOW CONTINUES TO LIFT NORTHEAST ACROSS
NORTHERN UTAH THIS MORNING. THIS LOW CONTRIBUTED TO SCATTERED
SHOWERS WHICH PERSISTED THROUGH THE OVERNIGHT HOURS ACROSS THE AREA.
AS A DRIER AND MORE STABLE AIRMASS WORKS ITS WAY INTO SOUTHERN
UTAH...SHOWERS WILL BECOME INCREASINGLY CONFINED TO THE NORTHEAST
TODAY...THEN TAPER OFF DURING THE EARLY EVENING HOURS AS THE STORM
SYSTEM EXITS THE AREA. AFTERNOON MAX TEMPERATURES TODAY ARE EXPECTED
TO BE WARMER THAN THEY WERE YESTERDAY DUE TO LESS PRECIPITATION AND
DECREASING CLOUD COVER.

A PERIOD OF QUIET WEATHER IS IN STORE BEGINNING TONIGHT AND
CONTINUING THROUGH MIDWEEK. AN UPPER RIDGE WILL TAKE RESIDENCE OVER
THE AREA BY LATE TONIGHT...THEN AMPLIFY AS IT SLOWLY SHIFTS EAST OF
THE AREA WEDNESDAY INTO THURSDAY. THIS IS IN ADVANCE OF A DEEPENING
PACIFIC TROUGH WHICH WILL SLOWLY ADVANCE INTO THE GREAT BASIN
TOWARDS THE END OF THE WEEK.

THE BUILDING RIDGE AND INCREASING SOUTH FLOW AS THE RIDGE SHIFTS EAST
WILL LEAD TO A CONTINUED WARMING TREND FOR THE NEXT FEW DAYS WITH
TEMPERATURES RETURNING TO ABOVE NORMAL VALUES ACROSS MOST AREAS
TOMORROW. MEANWHILE...DRIER AIR WILL CONTINUE TO SPREAD INTO THE
AREA LEADING TO MOSTLY CLEAR SKIES FOR THE MIDWEEK PERIOD.

REGARDING THE APPROACHING TROUGH...THE LATEST ECMWF IS NOW SLOWER IN
ITS PROGRESSION AS IT CLOSES OFF THE SYSTEM OVER NORTHERN CALIFORNIA
WHILE THE GFS PINCHES IT OFF OVER SOUTHWEST IDAHO. BOTH MODELS
INDICATE FRIDAY TO REMAIN ON THE WARM SIDE WITH BREEZY SOUTH
WINDS...ALTHOUGH THE GFS WOULD BE A BIT FASTER WITH THE MOISTURE.
THE BIGGEST CHANGE MADE TO THE FORECAST WAS TO RAISE TEMPERATURES A
FEW DEGREES FOR FRIDAY.  ALTHOUGH UNCERTAINTY REMAINS AS TO THE
TIMING AND EVOLUTION OF THE STORM SYSTEM...LATEST TRENDS STILL CALL
FOR COOLER AND WET CONDITIONS FOR THE WEEKEND.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED THROUGH THE VALID TAF
PERIOD. THERE IS A 30 PERCENT CHANCE OF PASSING RAIN SHOWERS
LOWERING CEILINGS BELOW 7000 FT AND THERE IS A 10 PERCENT CHANCE A
THUNDERSTORM WILL CROSS THE AIRFIELD UNTIL ABOUT 21Z. LIGHT
SOUTHEAST WINDS WILL SHIFT TO NORTHWESTERLY AROUND 19Z.

&&

.FIRE WEATHER...AN UPPER LOW WILL LIFT OUT OF THE DISTRICT TODAY BUT
WILL KEEP A THREAT OF SHOWERS AND ISOLATED THUNDERSTORMS GOING OVER
THE NORTHEAST INTO THE AFTERNOON WHILE THE SOUTH BEGINS TO WARM UP
AND DRY OUT. HIGH PRESSURE WILL BUILD INTO THE REGION TUESDAY AND
START TO SHIFT EAST WEDNESDAY. THIS WILL BRING A WARMER AND DRIER
AIRMASS TO THE ENTIRE REGION.

A PACIFIC STORM SYSTEM WILL GRADUALLY SETTLE INTO CALIFORNIA
THURSDAY THROUGH FRIDAY. THIS WILL BRING INCREASING SOUTH WINDS TO
THE DISTRICT BECOMING GUSTY IN THE AFTERNOONS. HOWEVER AFTERNOON
HUMIDITY WILL BE LOWEST ON WEDNESDAY THEN BEGIN RISING THURSDAY AND
FRIDAY AS THE SOUTHERLY FLOW STARTS TO DRAW TROPICAL MOISTURE BACK
NORTHWARD INTO THE REGION. ALTHO WINDS COULD REACH CRITICAL LEVELS
THURSDAY AND FRIDAY AND POSSIBLY ON SATURDAY...HUMIDITY IS FORECAST
TO BE TOO HIGH TO SUPPORT CRITICAL FIRE WEATHER CONDITIONS...EVEN
IF FUELS MANAGED TO DRY OUT SUFFICIENTLY BY THIS TIME.

THIS MOISTURE WILL BRING A THREAT OF ISOLATED SHOWERS AND
THUNDERSTORMS STARTING FRIDAY AFTERNOON WITH STORMS BECOMING MORE
NUMEROUS INTO THE WEEKEND AS THE CALIFORNIA LOW STARTS SHIFTING INTO
THE GREAT BASIN.

&&

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

$$

CHENG/WILENSKY

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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