FXUS65 KSLC 010414
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
914 PM MST MON NOV 30 2009

.SYNOPSIS...A SYSTEM DROPPING THROUGH THE HIGH PLAINS WILL SEND A
MOSTLY DRY COLD FRONT ACROSS UTAH ON TUESDAY. A COLD DRY NORTHERLY
FLOW WILL FOLLOW FOR WEDNESDAY AND THURSDAY.

&&

.DISCUSSION...A LARGE SCALE RIDGE REMAINS IN THE ERN PAC AND A
CLOSED LOW OVER NWRN MEX IS MOVING E. AN E-W ORIENTED SHORT WAVE
EXTENSION OF THE ERN PAC RIDGE OVER THE AREA THIS EVENING IS
SHIFTING SOUTH AND WEAKENING AS A COLD SHORT WAVE TROF BEGINS TO
DROP SOUTH OUT OF THE CANADIAN ROCKIES AND INTO THE NRN PLAINS
STATES.

MOST OF THE MOISTURE AND THE COLDEST AIR ALOFT WITH THIS FEATURE
WILL REMAIN TO OUR EAST AS IT DROPS SOUTH THRU THE WRN PLAINS TUE
THRU WED. THE LOW LEVEL COLD AIR IS FORECAST TO CROSS OUR CWA
HOWEVER AND THERE MAY BE JUST ENOUGH MOISTURE AND LOW LEVEL
INSTABILITY FOR SOME CLOUDINESS OVER THE NERN 1/2 OF THE CWA.
THERE MAY ALSO BE A FEW FLURRIES OVER WY AND THE UINTA AND NRN
WASATCH MTNS TUE NIGHT INTO WED.

THE FRONT CROSSES NRN UT TUE MORNING REACHING SRN UT LATE IN THE
DAY THEN MOVES OUT OF THE CWA BY MIDNIGHT. THE AIRMASS KEEPS
COOLING THRU THU MORNING WITH THE NEW 00Z NAM NOW INDICATING -16C
700MB AIR BY 18Z THU. 

IF NOTHING ELSE...THIS COLD NORTHERLY FLOW SHOULD MIX OUT ALL THE
VALLEYS KEEPING INVERSIONS FROM DEVELOPING AND AIR QUALITY FROM
DETERIORATING. 

ALL MODELS ARE IN FAIRLY CLOSE AGREEMENT THRU 00Z FRI WITH THE EC
NOT QUITE AS COLD AS THE GFS AND NAM...AND FORECAST CONFIDENCE IS
FAIRLY HIGH THRU THAT TIME.

REGARDING THE WEEKEND...THE 18Z GFS WENT AWAY FROM THE 12Z RUN AND
TOWARDS THE EC SOLUTION AGAIN...BUT WAS MUCH DRIER FOR NRN UT. SO
CONFIDENCE REMAINS VERY LOW IN FORECAST BEYOND FRI. FOR NOW...NO
UPDATES NEEDED. 

&&

.AVIATION...THE SLC TERMINAL WILL SEE VFR CONDITIONS THROUGH THE 
NIGHT WITH SOME HIGH CLOUDS. WINDS ARE EXPECTED TO REMAIN OUT OF THE 
SOUTHEAST UNTIL A COLD FRONT SHIFTS WINDS TO THE NORTHWEST BETWEEN 
15Z AND 17Z.

&&

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

&&

$$

WILENSKY/TRAPHAGAN

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