Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 262308
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
408 PM MST MON JAN 26 2015

.SYNOPSIS...STRONG HIGH PRESSURE ALOFT WILL RESIDE ACROSS UTAH
TODAY. THIS HIGH WILL SHIFT EAST TONIGHT...ALLOWING A STORM
SYSTEM OFF OF BAJA CALIFORNIA TO MOVE NORTHWARD AND AFFECT THE
REGION BEGINNING LATE TONIGHT AND CONTINUING THROUGH WEDNESDAY.

&&

.SHORT TERM (THROUGH 00Z FRIDAY)...HIGH PRESSURE STILL IN PLACE OVER
UTAH THIS AFTERNOON KEEPING A DRY AND STABLE AIRMASS IN PLACE. SOME
HAZE EVIDENT ALONG THE URBAN CORRIDOR...OTHERWISE SUNNY SKIES AND
QUITE WARM UNDERNEATH ANOMALOUSLY HIGH H7 TEMPERATURE OF AROUND 7C
OVER NORTHERN UTAH.

UPPER LOW CURRENTLY SPINNING OFF THE BAJA COAST STILL ON TRACK TO
EJECT INLAND TONIGHT...WITH OPEN-WAVE FEATURE TRACKING ACROSS
EASTERN NEVADA AND INTO NORTHERN UTAH TOMORROW. STORM CURRENTLY
TAPPING SIGNIFICANT MOISTURE OVER SOUTHERN CALIFORNIA AND
ARIZONA...BUT THIS MOISTURE TAP IS PROGGED TO CUT OFF AS THE STORM
APPROACHES UTAH. STILL...EXPECT PRECIPITATION TO BEGIN OVER SOUTHERN
UTAH LATE TONIGHT AND SPREAD NORTHWARD THROUGH THE DAY TOMORROW BUT
WITH LOW QPF. THE TROUGH WILL THEN CROSS WEST TO EAST ACROSS
NORTHERN UTAH TOMORROW NIGHT INTO WEDNESDAY FOCUSING SHOWERS MORE
ACROSS THE NORTH WHILE SOUTHERN UTAH DRIES OUT.

RELATIVELY MILD AIRMASS CONSISTENT WITH THE PACIFIC ORIGINS OF THIS
STORM...WITH H7 TEMPERATURES REMAINING WARMER THAN -6C THROUGHOUT
THE STORM. HIGH SNOW LEVELS...HIGH DENSITY SNOW AND LOW QPF RENDER
THIS A RELATIVELY INSIGNIFICANT SNOW EVENT. OTHER THAN THE MINOR
PRECIPITATION...EXPECT TEMPERATURES NEXT COUPLE OF DAYS TO GRADUALLY
TREND DOWNWARD FROM THE WELL ABOVE-NORMAL HIGHS OF LATE.

THURSDAY SHOULD PROVIDE A BREAK IN THE WEATHER AS TRANSIENT HIGH
PRESSURE SPREADS INTO THE AREA. THIS IS IN ADVANCE OF THE NEXT STORM
DEVELOPING UPSTREAM. GFS DOES EJECT A PIECE OF ENERGY THROUGH UTAH
THURSDAY AFTERNOON WHICH WOULD SPREAD PRECIPITATION TO THE AREA.
HOWEVER THIS IS IN CONTRAST TO THE EC/NAM/GEM SOLUTIONS WHICH ARE
MUCH DRIER FOR THAT PARTICULAR TIMEFRAME. HAVE CONTINUED TO LEAN
TOWARDS THE DRIER CONSENSUS BY KEEPING LITTLE TO NO POPS OVER THE
AREA FOR THURSDAY.

&&

.LONG TERM (AFTER 00Z FRIDAY)...THURSDAY NIGHT AND FRIDAY THE LOW
CONTINUES TO SPIN SOUTHWEST OF THE FORECAST AREA...WITH CHANCES OF
PRECIPITATION INCREASING ACROSS THE CWA AS THE LOW SLOWLY MEANDERS
EASTWARD. THE BEST CHANCE FOR SIGNIFICANT PRECIP WILL BE ACROSS
CENTRAL AND SOUTHERN UTAH...BUT SOME SHOWERS COULD ALSO BE POSSIBLE
ACROSS THE WASATCH FRONT AND UINTA COUNTY WY. HAVE SLIGHTLY RAISED
POPS IN SOME AREAS...BUT IN GENERAL LEFT THE ONGOING FORECAST IN
PLACE.

PRECIP LOOKS TO LINGER INTO SATURDAY...BEFORE THE LOW EXITS INTO
MEXICO AND DRIER AIR MOVES INTO UTAH FROM THE NORTHWEST. A COOL AND
STABLE NORTHWEST FLOW THEN ESTABLISHES ITSELF OVER THE AREA FOR
SUNDAY...WITH THE MEAN WESTERN CONUS RIDGE CENTERED OVER CALIFORNIA.

THE RIDGE FLATTENS A BIT FOR SUNDAY NIGHT AND MONDAY...ALLOWING SOME
LOW LEVEL MOISTURE TO APPROACH THE UTAH/IDAHO BORDER FROM THE NORTH.
HAVE SLIGHTLY INCREASED POPS IN THE NORTHERN MOUNTAINS TO ACCOUNT
FOR THE CHANCE OF SOME OROGRAPHIC PRECIP. LOOKING BEYOND DAY
7...UNCERTAINTY BEGINS TO INCREASE...AS THE GFS AND ECMWF DISAGREE
ON WHETHER THE RIDGE RE-AMPLIFIES OVER THE WEST HEADING INTO THE
MIDDLE OF NEXT WEEK. THAT SAID...GOOD MODEL AGREEMENT THROUGH DAY 7
LED TO MORE CONFIDENCE IN THE EXTENDED FORECAST THAN HAS BEEN THE
NORM RECENTLY...WITH THE MAIN SOURCE OF UNCERTAINTY BEING THE
PLACEMENT/MOVEMENT OF THE CLOSED LOW THURSDAY NIGHT THROUGH
SATURDAY.

&&

.AVIATION...NORTH TO NORTHWESTERLY WINDS AROUND 5 KTS AT THE SLC
TERMINAL WILL CONTINUE THROUGH 02-04Z TONIGHT. OTHERWISE...CLOUDS
WILL BEGIN TO INCREASE TUESDAY MORNING AHEAD OF WEATHER DISTURBANCE
THAT WILL IMPACT THE AREA THROUGH WEDNESDAY.

&&

&&

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

$$

CHENG/SCHOENING/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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