Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 192108
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
308 PM MDT SUN OCT 19 2014

.SYNOPSIS...A DRY AND MILD SOUTHWESTERLY FLOW WILL DEVELOP
MONDAY...AHEAD OF A PACIFIC TROUGH WHICH WILL CROSS NORTHERN UTAH
TUESDAY. HIGH PRESSURE WILL FOLLOW FOR THE REMAINDER OF THE WEEK.


&&

.SHORT TERM (THROUGH 00Z THURSDAY)...MID LEVEL RIDGING ENCOMPASSES
THE NORTHERN AND CENTRAL ROCKIES REGION EARLY THIS
AFTERNOON...WHILE FURTHER SOUTH AN UPPER LOW IS SLOWLY WORKING ITS
WAY EASTWARD ALONG THE US/MEXICO BORDER REGION. MOISTURE WRAPPING
AROUND THE NORTH SIDE OF THIS LOW WILL REMAIN CONFINED SOUTH OF
THE FORECAST AREA INTO THE EVENING HOURS...AND ALTHOUGH LIMITED
MOISTURE DOES REMAIN ACROSS SOUTHERN UT...SUPPRESSION FROM THE
PROXIMITY OF THE UPPER RIDGE HAS THUS FAR SIGNIFICANTLY LIMITED
CONVECTIVE GROWTH ACROSS THIS AREA. COULD STILL SEE A COUPLE OF
SHOWERS DEVELOP THROUGH THE REMAINDER OF THE AFTERNOON OVER THE
SOUTHERN MOUNTAINS...OTHERWISE A VERY QUIET EVENING IS IN STORE
WITH CLEARING SKIES AND LIGHT WINDS.

A DEEP LAYER SOUTHWESTERLY FLOW WILL DEVELOP MONDAY ACROSS THE
REGION...DOWNSTREAM FROM A SHORTWAVE TROUGH CURRENTLY OFF THE
PACIFIC COAST. THIS FLOW WILL MAINTAIN A VERY MILD AND GENERALLY
DRY AIRMASS ACROSS THE FORECAST AREA...WITH MAX TEMPERATURES
GENERALLY RUNNING 10 DEGREES ABOVE CLIMO. MODEST LINGERING
MOISTURE ACROSS SOUTHERN UT MAY ALLOW FOR ISOLATED HIGH BASED
CONVECTION DURING THE AFTERNOON HOURS.

THIS SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT ARE FORECAST TO
LIFT EAST-NORTHEAST ACROSS THE NORTHERN GREAT BASIN DURING THE DAY
TUESDAY. ALTHOUGH THE STRONGEST UPPER FORCING AND COLD AIR ALOFT
WILL PASS NORTH OF THE FORECAST AREA...SUFFICIENT LIFT ALONG WITH
AN INFLUX OF MOISTURE WILL ALLOW FOR SHOWERS AND ISOLATED
THUNDERSTORMS ACROSS THE NORTHERN HALF OF THE FORECAST AREA DURING
THE DAY TUESDAY...WITH THE COLD FRONT SWEEPING THROUGH THE
WASATCH FRONT DURING THE EARLY AFTERNOON HOURS. RAISED POPS 20-30
PERCENT DURING THE MORNING HOURS ACROSS AREAS NORTH OF I-80 WITHIN
THE PRE-FRONTAL ENVIRONMENT...AND DURING THE AFTERNOON ACROSS THE
NORTHERN HALF OF THE AREA WITH THE PASSAGE OF THE FRONT. SNOW
LEVELS TUESDAY AFTERNOON WILL LIKELY REMAIN ABOVE 8500 FEET WITH
PERHAPS A COUPLE INCHES OF ACCUMULATION ON THE HIGHER PEAKS. AS
THE PARENT WAVE QUICKLY CONTINUES LIFTING AWAY FROM THE AREA
PRECIPITATION SHOULD QUICKLY WIND DOWN BY TUESDAY EVENING WITH
SEASONAL TEMPERATURES EXPECTED WEDNESDAY.

&&

.LONG TERM (AFTER 00Z THURSDAY)...A FEW CHANGES TO NOTE IN GLOBAL
GUIDANCE FOR THE LATTER PERIODS. RIDGE AMPLIFICATION ACROSS THE
EASTERN GREAT BASIN IS NOT AS PRONOUNCED AS EARLIER RUNS BUT WILL
REMAIN DOMINANT HEADING INTO THE WEEKEND. GFS HAS BEEN KEYING INTO
THIS AT TIMES OVER THE LAST FEW DAYS BUT NOW BOTH IT AND THE ECMWF
SHOW SIMILAR OUTPUT REGARDING A POTENTIAL UPSTREAM SHIFT IN THE
PATTERN AS THE EASTERN PACIFIC LONG WAVE TROUGH APPEARS TO BE A BIT
MORE PROGRESSIVE...SHIFTING INLAND LATE NEXT WEEKEND. THOUGH TIMING
REMAINS OFF BY 24 HOURS REGARDING INITIAL IMPACTS OF A POTENTIALLY
POTENT FALL TROUGH...00Z SUN GFS VS. 00Z MON ECMWF...CONFIDENCE IS
TRENDING TO GROW REGARDING A PATTERN SHIFT OCCURRING LATE IN THE
FORECAST PERIOD.

MAINTAINED DRY AND UNSEASONABLY WARM CONDITIONS THROUGH
SATURDAY...AS RIDGE POSITIONS OVERHEAD THEN SHIFTS EAST ALLOWING
STRENGTHENING SOUTHWESTERLY FLOW ALOFT TO DEVELOP. ADDED SLIGHT
CHANCE POPS FOR DAY 7 AND BEGAN A TREND TO LOWER SNOW LEVELS/TEMPS
SUNDAY DUE TO POTENTIAL OF TROUGH NOSING IN BY THEN.

&&

.AVIATION...NO SIGNIFICANT OPERATIONAL WEATHER CONCERNS TO NOTE AT
THE KSLC TERMINAL FOR THE VALID TAF PERIOD. LIGHT NORTHWEST SURFACE
WINDS WILL SWITCH BACK TO THE SOUTHEAST BETWEEN 03-04Z PER NORM.

&&

&&

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

$$

SEAMAN/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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