Area Forecast Discussion
Issued by NWS Salt Lake City, UT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
000
FXUS65 KSLC 222242
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
342 PM MST THU JAN 22 2015

.SYNOPSIS...A VERY WEAK SYSTEM WILL SLIDE SOUTH ACROSS EASTERN
UTAH FRIDAY THROUGH FRIDAY NIGHT. STRONG HIGH PRESSURE WILL BUILD
INTO THE WESTERN STATES SATURDAY THROUGH EARLY NEXT WEEK.

&&

.DISCUSSION...A SHORT WAVE RIDGE IS OVER THE CWA TODAY WITH CLEAR
SKIES AND A DRY STABLE AIRMASS IN PLACE.

THE RIDGE AXIS CROSSES THE CWA TONIGHT AS A VERY WEAK SPLITTING
SHORT WAVE TROF MOVES THRU THE NRN ROCKIES AND GRAZES THE NERN CWA
TOMORROW. THE AIRMASS ALOFT IS WARMING TODAY AND WILL COOL A
LITTLE WITH THE PASSING WAVE TOMORROW BUT THIS WILL NOT HAVE MUCH
IMPACT ON THE DEVELOPING VALLEY INVERSIONS. ABOUT THE ONLY RESULT
OF THE PASSING WAVE WILL BE INCREASING MID AND HIGH CLOUDINESS
ACROSS THE CWA TONIGHT AND SOME LOWER CLOUDS OVER THE NERN ZONES
FRI ALONG WITH A SMALL CHANCE OF LIGHT SNOW IN THE UINTAS IN THE
AFTN.

THE SURFACE GRADIENT DOES RESPOND TO THIS PASSING WAVE HOWEVER AND
LOCAL BREEZY NORTH WINDS ARE POSSIBLE AGAIN ACROSS SRN UT FRI
NIGHT INTO SAT...WITH THE STRONGEST WINDS ACROSS WASHINGTON CO.

THE SRN PORTION OF THE SPLITTING WAVE HEADS SOUTH AND EVENTUALLY
FORMS A CLOSED LOW IN THE TROPICAL ERN PAC WEST OF THE BAJA
PENINSULA BY SUN MORNING AND STARTS TAPPING INTO TROPICAL
MOISTURE.

MEANWHILE THE ERN PAC RIDGE BUILDS GRADUALLY INTO THE WESTERN
STATES SAT THRU SUN NIGHT.

&&

.LONG TERM (AFTER 00Z MONDAY)...THE HIGH AMPLITUDE RIDGE REMAINS
OVER THE WESTERN CONUS FOR SUNDAY NIGHT AND MONDAY...WITH CONTINUING
DRY AND WARM CONDITIONS ACROSS THE FORECAST AREA.

THE PACIFIC LOW THAT PASSED THROUGH THE AREA FRIDAY NIGHT RETURNS
TO THE GREAT BASIN FROM THE SOUTH THROUGH THE DAY TUESDAY...
BRINGING A VERY MOIST AIRMASS ALONG WITH IT. HOW MUCH FORCING
THERE WILL BE WITH THIS WAVE IS SOMEWHAT UNCERTAIN...ESPECIALLY
BECAUSE RECENT RUNS OF THE ECMWF HAVE KEPT THE CORE OF THE LOW
WEST OF THE AREA...BUT THE MOISTURE SURGE ALONG WITH AT LEAST SOME
MINIMAL FORCING WOULD PROVIDE A CHANCE OF PRECIPITATION ACROSS
MOST OF THE CWA. THERE IS ALSO SOME DISCREPANCY ABOUT HOW COLD THE
AIRMASS WILL BE WITH THIS WAVE...WITH THE GFS INDICATING SNOW
LEVELS AROUND 7000FT...WHILE THE EC WOULD PUT SNOW LEVELS CLOSER
TO 9000FT FOR TUESDAY/WEDNESDAY. CURRENT FORECAST IS A BIT OF A
COMPROMISE BETWEEN THESE TWO SOLUTIONS.

THAT WAVE DISSIPATES A BIT AS IT MOVES FURTHER INLAND...AND THE
REMNANTS LOOK TO LINGER OVER NORTHERN UTAH ON WEDNESDAY. BEYOND
WEDNESDAY...GLOBAL MODELS BEGIN TO DIVERGE A BIT...BUT THE GENERAL
IDEA IS THAT INCREASED MOISTURE WILL LIKELY STICK AROUND THROUGH AT
LEAST THURSDAY. IN GENERAL...HAVE INCREASED POPS THROUGH MUCH OF THE
EXTENDED...WITH THIS MOISTURE SURGE REPRESENTING THE BEST CHANCE OF
WIDESPREAD PRECIPITATION IN MORE THAN A WEEK.

&&

.AVIATION...WINDS AT THE SLC TERMINAL ARE EXPECTED TO SWITCH BACK TO
THE SOUTH BETWEEN 02Z AND 04Z. CEILINGS WILL LIKELY LOWER THROUGH
THE OVERNIGHT HOURS...BUT SHOULD REMAIN ABOVE 7000FT THROUGH AT
LEAST 10Z.

&&

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

$$

SHORT TERM...WILENSKY
LONG TERM/AVIATION...SCHOENING

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)


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.