Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 242306
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
406 PM MST SAT JAN 24 2015

.SYNOPSIS...STRONG HIGH PRESSURE WILL BUILD INTO THE WESTERN
STATES SUNDAY AND MONDAY...BEFORE A STORM SYSTEM PASSES THROUGH
THE AREA MONDAY NIGHT THROUGH WEDNESDAY.



&&

.SHORT TERM (THROUGH 00Z WEDNESDAY)...UTAH AND SOUTHWEST WYOMING
ARE BETWEEN TWO MAJOR FEATURES THIS AFTERNOON...A HIGH AMPLITUDE
RIDGE OVER THE WEST COAST...AND A TROUGH OVER THE GREAT PLAINS.
THIS PUTS THE FORECAST AREA INTO A RELATIVELY MILD NORTH-NORTHWEST
FLOW...WITH SOME CLOUD COVER MOVING ACROSS THE NORTHERN AND
EASTERN PORTIONS OF THE CWA. A LOW LEVEL STRATUS DECK HAS MOVED
OVER THE NORTHERN HALF OF THE AREA...AND WILL LIKELY LINGER
THROUGH MUCH OF THE NIGHT...BEFORE DISSIPATING SUNDAY MORNING.

THE RIDGE IS FORECAST TO SHIFT OVER THE GREAT BASIN ON
SUNDAY...AND THEN OVER THE ROCKIES BY MONDAY AFTERNOON.
TEMPERATURES BECOME QUITE WARM DURING THIS PERIOD OF TIME...WITH
700MB TEMPERATURES LIKELY RISING TO THE 4-6 DEGREE CELSIUS RANGE.
EVEN WITH SOME WEAK INVERSIONS OR ISOTHERMAL SOUNDINGS IN THE
LOWER LEVELS...THIS SHOULD LEAD TO WARMER THAN SEASONAL
TEMPERATURES ACROSS PRETTY MUCH THE ENTIRE CWA.

THE RIDGE SHIFTS EAST OF THE AREA BY LATE MONDAY...AND THIS ALLOWS
A PACIFIC LOW TO MOVE THROUGH SOUTHERN CALIFORNIA AND INTO THE
GREAT BASIN MONDAY NIGHT INTO TUESDAY. THE AIRMASS WITH THIS LOW
IS QUITE MOIST...SO EXTENSIVE CLOUD COVER AND DECENT COVERAGE OF
PRECIPITATION IS LIKELY...EVEN IF THE BEST INSTABILITY REMAINS
WEST OF THE CWA. HAVE GENERALLY INCREASED POPS THROUGH THE DAY
TUESDAY...AS THE MODELS HAVE BEEN FAIRLY CONSISTENT IN BRINGING
THIS MOISTURE THROUGH THE AREA WITH AT LEAST SOME WEAK FORCING.

&&

.LONG TERM (AFTER 00Z WED)...THE WEAKENING REMAINS OF THE TROPICAL
ERN PAC CLOSED LOW ARE FORECAST TO CROSS THE NRN CWA TUE NIGHT AS A
VERY MOIST BUT WEAK OPEN WAVE. ABUNDANT MOISTURE PLUS WEAK DYNAMICS
SHOULD SUPPORT FAIRLY WIDESPREAD PRECIP ACROSS THE NORTH. MOST OF IT
SHOULD BE LIGHT BUT THERE SHOULD BE SOME OROGRAPHIC COMPONENT THAT
COULD RESULT IN MODEST WATER AMOUNTS FOR THE WASATCH FRONT AND
ADJACENT MTNS. SNOW LEVELS SHOULD BE AROUND 6000 FT AND ACCUMULATION
COULD BE SUFFICIENT TO HAVE AN IMPACT ON TRAVEL ABOVE THAT LEVEL
WED MORNING.

THIS WAVE SHIFTS EAST WED AND PRECIP TAPERS OFF ALTHO SOME MOISTURE
IS LEFT BEHIND. A NEW LOW BEGINS TO LIFT OUT OF THE SUBTROPICAL ERN
PAC AND SPREADS ADDITIONAL MOISTURE INTO THE SWRN STATES STARTING
THU. MODELS HAVE BEEN STRUGGLING WITH HOW THIS MOISTURE INTERACTS
WITH A WEAK WAVE COMING OVER THE TOP OF THE ERN PAC RIDGE THU NIGHT
INTO FRI. THE 12Z GFS HAD A STRONGER WAVE AND WAS MUCH WETTER THRU
THE END OF THE WEEK AS A RESULT. THE EC AND NEW 18Z GFS HAVE A MUCH
WEAKER WAVE AND WERE NOT QUITE AS GENEROUS WITH PRECIP AMOUNTS BUT
HAVE MORE MOISTURE OVER THE CWA THU NIGHT THRU FRI NIGHT THAN
EARLIER RUNS. SO HAVE INTRODUCED SLIGHTLY GREATER THAN CLIMO POPS
FOR THIS TIME FRAME BUT CONFIDENCE REMAINS QUITE LOW ON HOW THIS
PATTERN WILL ACTUALLY EVOLVE.

BOTH MODELS DO PUSH THE MOISTURE OFF TO THE SOUTH STARTING SAT AND
FOLLOWED THIS DRYING TREND IN THE GRIDS.

&&

.AVIATION...NORTH TO NORTHWEST WINDS WILL CONTINUE AT THE SLC
TERMINAL THROUGH 02-04Z. CEILINGS NEAR 5000 FEET AGL WILL CONTINUE
THROUGH 12Z OR SO SUNDAY MORNING.

&&

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

$$

SHORT TERM...SCHOENING
LONG TERM...WILENSKY
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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