FXUS65 KSLC 261700
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1000 AM MST SAT DEC 26 2009
.SYNOPSIS...WEAK HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY
THROUGH SUNDAY THEN SHIFT EAST MONDAY. A WEAK AND GENERALLY DRY
DISTURBANCE FROM THE PACIFIC WILL SLOWLY PASS THROUGH THE REGION
EARLY NEXT WEEK.
&&
.DISCUSSION...MORNING WATER VAPOR IMAGERY AND UPPER AIR ANALYSIS
SHOW THE FORECAST AREA RESIDES UNDER A MID LEVEL
COL...CHARACTERIZED BY A DEEP UPPER LOW RESIDING ACROSS THE
MIDWEST AND A UPPER TROUGH ENCOMPASSING THE EASTERN
PACIFIC...WHILE A BLOCKING UPPER HIGH RESIDES TO THE NORTH ACROSS
THE CANADIAN ROCKIES AND A WEAKER MID LEVEL RIDGE TO THE SOUTH
OVER THE LOWER CO RIVER VALLEY. AREA OF STRATUS/FOG REMAINS ACROSS
NORTHERN UT...AND GIVEN LIGHT FLOW ALOFT AND FAIRLY ABUNDANT LOW
LEVEL MOISTURE SUSPECT LOW CLOUDS TO MAINTAIN OR EVEN EXPAND
DURING THE AFTERNOON...PARTICULARLY ACROSS THE WEST DESERT AS WELL
AS THE WASATCH FRONT NORTH OF I-80. WILL LIKELY UPDATE GOING
GRIDS/ZONES ACCORDINGLY LATER THIS MORNING AFTER MONITORING
SATELLITE TRENDS.
PRIMARY CONCERN THE NEXT FEW DAYS LOOKS TO BE INCREASING
STAGNATION ACROSS NORTHERN VALLEYS AS FLOW ALOFT REMAINS QUITE
WEAK. ONE LIMITING FACTOR WILL BE RELATIVELY COOL 700MB
TEMPS...WHICH ARE FORECAST TO REMAIN IN THE -8 TO -10C RANGE. FOG
MAY ALSO BECOME AN INCREASING CONCERN...ALTHOUGH COMBINATION OF
STRATUS ALREADY IN PLACE AND INCREASING MID AND HIGH LEVEL
MOISTURE MAY LIMIT WIDESPREAD FOG POTENTIAL.
A SHORTWAVE TROUGH IS EXPECTED TO SPREAD ACROSS THE DESERT
SOUTHWEST AND NORTHERN MX EARLY NEXT WEEK. APPRECIABLE DYNAMIC
FORCING AND ATTENDANT PRECIPITATION THREAT LOOK TO REMAIN SOUTH OF
THE AZ BORDER...ALTHOUGH MOISTURE SPREADING INTO CENTRAL AND
SOUTHERN UT MAY ALLOW FOR A PERIOD OF LIGHT SNOW ACROSS THE HIGHER
TERRAIN LATE MONDAY INTO TUESDAY.
OTHERWISE BLOCKING CANADIAN HIGH EXPECTED TO BREAK DOWN EARLY NEXT
WEEK ALLOWING A NORTHWESTERLY FLOW ALOFT TO DEVELOP ACROSS THE
INTERMOUNTAIN WEST. A SERIES OF FAIRLY WEAK EMBEDDED SHORTWAVES
ARE EXPECTED TO PASS THOUGH THIS FLOW DURING THE MIDDLE TO LATTER
PORTION OF NEXT WEEK. DIFFICULT AT THIS POINT TO SAY WHETHER ANY
OF THESE FEATURES WILL BE SUFFICIENT TO COMPLETELY DISLODGE VALLEY
INVERSIONS ACROSS NORTHERN UT AS CONSIDERABLE SPREAD EXISTS
BETWEEN THE GFS...EC AND GEM.
&&
.AVIATION...THE SLC TERMINAL IS EXPECTED TO SEE LIGHT WINDS AND
SLOWLY CLEARING SKIES THROUGH TODAY...WITH ONLY A 20 PERCENT CHANCE
THAT CEILINGS BELOW 7000FT AGL RE-FORM BEFORE 00Z SUNDAY. LIGHT
SOUTHERLY SURFACE WINDS SHOULD SLOWLY SWITCH TO THE NORTHWEST
BETWEEN 18Z AND 20Z.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...NONE.
&&
$$
SEAMAN/SCHOENING
FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)
