Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 010845
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
245 AM MDT WED OCT 1 2014

.SYNOPSIS...A COOL PACIFIC STORM WILL MOVE THROUGH THE AREA
TONIGHT THROUGH WEDNESDAY. HIGH PRESSURE WILL BUILD OVER THE AREA
THURSDAY THROUGH AT LEAST EARLY NEXT WEEK.

&&

.SHORT TERM (THROUGH 00Z SATURDAY)...
WATER VAPOR LOOP SHOWS THE FINAL DISTURBANCE WITHIN THE WESTERN
LONG WAVE TROUGH APPROACHING FROM SOUTHWEST IDAHO. AMDAR 400-250MB
WIND OBSERVATIONS REVEAL A CYCLONIC 100-120KT JET OVER THE WEST
COAST AND NOSING INTO SOUTHWEST UTAH. GOES/GPS/RAP/00Z RAOB
INDICATE THE PRECIPITABLE WATER VALUE RANGES BETWEEN 0.25" IDAHO
BORDER/NORTHEAST AND SOUTHERN MOUNTAINS....TO 0.70" CENTRAL
VALLEYS.

RAP 850-700MB STREAMLINES AND SATURATED EQUIVALENT POTENTIAL
TEMPERATURE PLOT INDICATE THE BAROCLINIC ZONE WILL CROSSING INTO
NORTHERN ARIZONA THIS MORNING. MEANWHILE...TWO ZONES OF
PRECIPITATION INTEREST EXIST. FIRST...ACROSS CENTRAL UTAH WHERE LARGE
SCALE LIFT IS BEING AIDED BY THE EXIT REGION OF THE AFOREMENTIONED
JET. THIS AREA SHOULD CONTINUE TO SLIDE EASTWARD OUT OF THE
FORECAST AREA THIS MORNING.

SECOND...DESTABILIZATION TAKING PLACE DUE TO THE ARRIVAL OF THE COLD
CORE ALOFT AND DAYTIME HEATING. HAVE SCATTERED POPS MENTIONED FOR
CONVECTIVE SHOWERS ACROSS THE NORTH...WITH THREAT OF THUNDER.
DAYTIME WARMING SHOULD NEGATE SOME OF THE COLD
ADVECTION...LEADING TO SNOW LEVELS PRETTY STEADY AT 7KFT TODAY.

ADDITIONAL INSTABILITY WILL BE PROVIDED BY THE GREAT SALT LAKE THIS
MORNING. 700MB TEMPERATURE NEAR -4C AND LAKE SURFACE TEMPERATURE
NEAR 20C ARE SUPPLYING 1500-2000 J/KG CAPE WITH AN EQUILIBRIUM LEVEL
NEAR 28KFT AND NCAPE BETWEEN 0.19-0.28.

PRECIPITATION DIMINISHES ACROSS THE NORTHEAST THIS EVENING...WITH
CLEARING TAKING PLACE BEHIND THE WAVE OVERNIGHT.

DOWNSLOPE WINDS ARE THE SECOND THREAT DURING THE SHORT
TERM...HOWEVER ARRIVAL OF STRENGTHENING PRESSURE GRADIENT AND 700MB
COLD ADVECTION ACROSS CENTRAL AND SOUTHERN UTAH DURING THE DAYTIME
TODAY APPEARS TO BE MIS-ALIGNED WITH CLIMATOLOGICAL BEST TIMING
FOR STRONG WIND EVENTS. AS SUCH...EXPECT GUSTY NORTHWEST DOWNSLOPE
WINDS ACROSS CASTLE COUNTRY...AND NORTHEAST WINDS ACROSS PORTIONS
OF WASHINGTON COUNTY TODAY...BELOW ADVISORY CRITERIA. THE THREAT
CONTINUES FOR WASHINGTON COUNTY TONIGHT...THOUGH WANING SETUP WILL
NEGATE OVERNIGHT TIMING. HAVE KEPT WINDS AT THE CUSP OF ADVISORY
SURROUNDING ST. GEORGE TONIGHT.

WINDS ACROSS NORTHERN AND CENTRAL UTAH ABATE TONIGHT WITH THE
SURFACE RIDGE BUILDING IN. THIS SHOULD PROVIDE AREAS OF
FROST...FREEZING TEMPERATURES AND FOG WITH CLEARING CONDITIONS. HAVE
ISSUED A HARD FREEZE WATCH FOR THE UINTA BASIN...SANPETE/SEVIER
VALLEYS AND SOUTHWEST VALLEYS WHERE THE GROWING SEASON HAS NOT YET
ENDED. DAY SHIFT WILL HAVE TO EVALUATE WHERE CONDITIONS ARE MOST
LIKELY FOR A WARNING. TEMPERATURES DID NOT APPEAR COLD ENOUGH
AROUND DELTA AT THIS TIME.

PATCHY FOG ALSO APPEARS LIKELY ACROSS NORMALLY COLDER VALLEYS. LOCAL
HIGH RESOLUTION WRF BUFKIT FORECAST SOUNDINGS FOG TECHNIQUE ARE
STRONGLY INDICATIVE OF FOG FORMATION.

EXPECTING A WARMING/DRYING TREND THURSDAY INTO FRIDAY WITH RISING
HEIGHTS ALOFT.

&&

.LONG TERM (AFTER 00Z SATURDAY)...
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE AREA...AMPLIFYING
FURTHER OVER THE WEEKEND AND REMAINING IN PLACE THROUGH AT LEAST
EARLY NEXT WEEK. TEMPERATURES WILL AVERAGE NEAR NORMAL
SATURDAY...BUT WILL WARM TO NEAR TO ABOVE NORMAL LEVELS BY EARLY
NEXT WEEK.

&&

.AVIATION...NORTH TO NORTHWEST WINDS WILL CONTINUE AT THE SLC
TERMINAL THROUGH THE DAY. SHOWERS WILL REMAIN POSSIBLE THROUGH THE
MORNING AND INTO THE AFTERNOON AND MAY BRING A REDUCTION TO A
CEILING AROUND 4000 FEET AGL OR SO FOR A PERIOD ALONG WITH ERRATIC
WINDS.

&&

.FIRE WEATHER...A COOL AND MOIST PATTERN REMAINS IN PLACE TODAY.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE INTO THIS
EVENING...WITH HIGH ELEVATION SNOWFALL A THREAT AS WELL. STRONG
GUSTY WINDS ARE POSSIBLE TODAY THROUGH TOMORROW MORNING...ESPECIALLY
ACROSS DOWNSLOPE/CANYON PORTIONS OF WASHINGTON COUNTY AND PERHAPS
CASTLE COUNTRY TO A LESSER EXTENT. A DRYING AND WARMING TREND IS
FORECAST FOR THE SECOND HALF OF THE WEEK.
&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...HARD FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
     UTZ011-014-016.

WY...NONE.
&&

$$

SHORT TERM/FIRE WEATHER...ROGOWSKI
LONG TERM/AVIATION...KRUSE

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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