FXUS65 KSLC 250422
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
922 PM MST THU DEC 24 2009

.SYNOPSIS...A COLD NORTHERLY FLOW WILL CONTINUE ACROSS UTAH TONIGHT
INTO SATURDAY. PATCHY MOISTURE IN THIS FLOW WILL CROSS
NORTHEASTERN PORTIONS OF THE AREA TONIGHT THROUGH FRIDAY. 

&&

.DISCUSSION...A HIGHLY AMPLIFIED RIDGE REMAINS ALONG THE WEST
COAST THIS EVE WITH A COOL NLY FLOW ACROSS OUR CWA. A WEAK SHORT
WAVE TROF IN THIS FLOW IS DROPPING THRU THE NRN ROCKIES AND WILL
CONTINUE TO MOVE SOUTHWARD OVER THE NEXT 18 HRS OR SO. THE LEADING
EDGE OF THE CLOUDINESS ASSOCIATED WITH THIS FEATURE HAS SPREAD
INTO NRN UT AND EXPECT THIS TO INCREASE ACROSS ABOUT THE NERN 1/3
OF THE FORECAST AREA OVERNIGHT INTO FRI MORNING. NOT MUCH DYNAMIC
SUPPORT FOR PRECIP WITH THIS WAVE BUT FLURRIES OR LOCAL LIGHT SNOW
IS POSSIBLE THRU FRI. THE BEST THREAT WOULD BE OVER THE UINTA MTNS
BUT FLURRIES COULD SPREAD AS FAR WEST AS THE WASATCH FRONT AND
CACHE VALLEY...AND IS POSSIBLE AS FAR S AS THE CENTRAL MTNS. 

LATEST 00Z NAM INDICATES THIS MOISTURE COULD PERSIST INTO EARLY
SAT AS THE SHORT WAVE TROF BECOMES A LOBE OF THE MASSIVE CENTRAL
US LOW AND EXTENDS WWD FRI AND FRI NIGHT. THIS WWD EXTENSION OF
THE LOW WILL BE MATCHED BY SHORT WAVES BEGINNING TO BREAK UNDER
THE RIDGE FROM THE WEST AS IT PINCHES OFF OVER WRN CANADA.

FOG IS MUCH LESS LIKELY TONIGHT AND FRI MORNING IN AREAS THAT
WILL SEE THE INCREASE IN CLOUD COVER BUT COULD STILL FORM IN AREAS
AWAY FROM THE CLOUDS. MIXING WILL REMAIN POOR ALONG THE WASATCH
FRONT HOWEVER SO AN INCREASE IN HAZE IS STILL EXPECTED FRI INTO
SAT. 

QUICK LOOK AT NEW 00Z GFS SHOWS A COMPLETE BREAK THRU UNDER THE
RIDGE AND THE DEVELOPMENT OF A WEAK LOW OVER UT ON SUN WITH
MOISTURE INCREASING ACROSS THE CWA. 

UPDATED FORECASTS FOR THE REST OF TONIGHT AND FRI TO ACCOUNT FOR
THE CLOUDS AND POSSIBLE FLURRIES BUT CONFIDENCE IN THE FORECAST
BEYOND FRI IS LOW IN LIGHT OF THE NEW DEVELOPMENTS IN THIS EVE
MODELS.

A QUICK NOTE OF INTEREST REGARDING THE STRONG RETURNS ON THE SALT
LAKE RADAR SOUTH OF THE GREAT SALT LAKE EARLIER IN THE EVE. WE
HAVE NOTICED THIS IN THE PAST AROUND THIS TIME OF YEAR AND OUR
SCIENCE OFFICER DID SOME RESEARCH INTO IT. IT SEEMS THAT THIS
NORTH-SOUTH LOBE OF BRIGHT RETURNS ARE MIGRATING BIRDS DEPARTING
FROM THE SHALLOWS AT THE SOUTH END OF THE LAKE AND HEADING
SOUTH...AND ARE LIKELY TUNDRA SWANS.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED TO PERSIST AT KSLC THROUGH 
TOMORROW. CEILINGS BELOW 6000FT ARE ANTICIPATED AROUND 07Z. CHANCE 
OF PATCHY FOG IN THE VICINITY OF THE TERMINAL IS 10 PERCENT. SURFACE 
WINDS WILL REMAIN LIGHT THROUGH THE PERIOD. 
 
&&

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

&&

$$

WILENSKY/YOUNG

FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)