781
FXUS65 KSLC 092129
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
229 PM MST MON NOV 9 2009
SYNOPSIS
A MILD SOUTHWEST FLOW WILL INCREASE THROUGH MIDWEEK. A
PACIFIC STORM SYSTEM WILL IMPACT THE GREAT BASIN FOR THE LATTER
PART OF THE WEEK.
DISCUSSION
AFTERNOON WATER VAPOR IMAGERY AND OBJECTIVE ANALYSIS
DEPICT A LONGWAVE TROUGH ENCOMPASSING THE EASTERN
PACIFIC...ANCHORED AROUND AN UPPER LOW SPINNING OVER THE GULF OF
AK. DOWNSTREAM A DEEP LAYER WEST-SOUTHWESTERLY FLOW ALOFT PREVAILS
ACROSS THE INTERIOR WEST. ABUNDANT MID AND HIGH LEVEL MOISTURE
EMBEDDED WITHIN THIS FLOW CONTINUES TO STREAM ONSHORE AND ACROSS
THE GREAT BASIN.
THIS FLOW ALOFT IS EXPECTED TO BACK TO SOUTHWESTERLY AND INCREASE
OVER THE NEXT COUPLE OF DAYS AS A MID LEVEL TROUGH DEVELOPS ALONG
THE PACIFIC COAST. TEMPERATURE FORECAST A LITTLE TRICKY THROUGH
WEDNESDAY...AS ALTHOUGH THIS FLOW SHOULD AID IN BOUNDARY LAYER
MIXING...MID AND HIGH LEVEL MOISTURE WILL LIKELY LIMIT SOLAR
INSOLATION SOMEWHAT...BUT ALSO KEEP OVERNIGHT MIN TEMPS A BIT
ELEVATED. HAVE ADJUSTED TEMPS UP A BIT...PRIMARILY ACROSS
NORTHERN UT VALLEYS...HOWEVER GENERALLY REMAINED IN THE MIDDLE OF
THE AVAILABLE GUIDANCE ENVELOPE. ANY APPRECIABLE THREAT FOR
PRECIPITATION THROUGH WEDNESDAY LOOKS TO REMAIN NORTH OF THE AREA
AS JET CORE DEVELOPS AND STRENGTHENS OVER THE PACIFIC NORTHWEST.
BY WEDNESDAY NIGHT THIS TROUGH IS EXPECTED TO SPREAD
INLAND...PUSHING A COLD FRONT INTO NORTHERN UT BY EARLY THURSDAY
MORNING. BEHIND THE SURFACE FRONT...ANTICIPATE A BAND OF
PRECIPITATION WITHIN 700-500MB TROUGH AXIS AS IT SAGS THROUGH
NORTHERN AND CENTRAL UT THURSDAY. NAM BUFR SOUNDINGS AND PROG
700MB TEMPS NEAR -6C SUGGEST ANY SNOWFALL SHOULD REMAIN ABOVE THE
VALLEY FLOORS ALONG THE WASATCH FRONT...WITH A CHANGEOVER LIKELY
ALONG THE BENCHES...ESPECIALLY ABOVE 5500 FT. EXPECT THIS BAND TO
SHIFT SOUTHEAST AND WEAKEN THURSDAY NIGHT ACROSS CENTRAL AND
SOUTHERN UT. HAVE ADJUSTED POPS UPWARD...MAINLY ACROSS NORTHERN UT
DURING THE DAY THURSDAY...AND OTHERWISE MAINTAINED SLIGHT
CHANCE/LOW CHANCE POPS ACROSS MUCH OF CENTRAL/SOUTHERN UT INTO
THURSDAY NIGHT.
A FAIR AMOUNT OF SPREAD EXISTS BETWEEN MEDIUM RANGE MODELS WITH
RESPECT TO HOW SECONDARY TROUGH...WHICH IS FORECAST TO PASS
THROUGH THE REGION LATE FRIDAY INTO THE UPCOMING WEEKEND. AS SUCH
HAVE COOLED TEMPERATURES A BIT OVER THE WEEKEND...AND KEPT A
MENTION OF PRECIPITATION ACROSS MAINLY THE NORTHERN THIRD OF THE
AREA SATURDAY.
AVIATION
VFR CONDITIONS TO PREVAIL THROUGHOUT THE PERIOD AT
KSLC. NORTH WINDS EXPECTED TO SWITCH BACK TO THE SOUTH DURING THE
02-04Z TIMEFRAME.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
SEAMAN
FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)
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