000 
FXUS65 KRIW 251010
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
310 AM MST WED DEC 25 2002

...TODAY THROUGH FRIDAY NIGHT...
LOOKS LIKE WE ARE GOING BACK TO THE ORIGINAL PLAN OF A SUSTAINED
SNOW EVENT FOR THE WESTERN MOUNTAINS BEGINNING LATE THURSDAY INTO THE
WEEKEND.  SHORTWAVE DIVING SOUTHEAST ACROSS UTAH EARLY THIS MORNING
NOT TO AFFECT OUR WX TODAY.  SURFACE HIGH PRESSURE WEST
OF DIVIDE TO KEEP LOW LEVEL MOISTURE TRAPPED UNDERNEATH WITH MID-
CLOUD DECK ALONG AND BEHIND DEFORMATION AXIS INCHING ITS WAY ACROSS
THE BORDER.  WITH VERY COLD TEMPS EXPECT VERY DRY -SN TO FALL
UNDERNEATH...MAYBE AN INCH OR TWO OF FLUFF BY THE TONIGHT.  KRIW
VELOCITY SCAN SHOWS INCREASING NW FLOW WITH CURRENT FOG AREAS BEING
KEPT IN CHECK...MAINLY NE OF RIW.  WILL NOT EVEN CONTEMPLATE MIXING
BASINS OUT UNTIL PACIFIC FRONT MOVES ACROSS THUR NGT OF WHICH
COLDER FWC TEMPS SEEM MORE REPRESENTATIVE.   SHORTWAVE AHEAD OF 140
KT JET STREAK CROSSING 140W EARLY THIS MORNING PROGGED TO MOVE OVER
FLAT RIDGE ACROSS B.C./ALBERTA THURSDAY AND INTENSIFY INTO NORTHERN
PLAINS THURSDAY NIGHT. ASSOCIATED PACIFIC COLD FRONT MOVES FROM WEST
COAST TO WESTERN BORDER 12Z THU-00Z FRI AND ACROSS STATE THUR NGT.
DEEPER MOISTURE MOVES INTO WEST THUR AFTN WITH MTN TOP WESTERLIES
INCREASING TO NEAR 50 KT BY FRI AFTN.  STRONGEST AND DEEPEST
VERTICAL MOTION PROGGED OVER WEST 18Z FRIDAY THROUGH EARLY
SATURDAY WHEN MAX OROGRAPHIC LIFT HOOKS UP WITH DIVERGENCE ALOFT.
WILL BEGIN LIKELY POPS W MTNS THUR AFTN INCREASING TO DEFINITE WITH
FROPA THUR NGT.  QPF CHARTS GENERATING 1.75 MAX THUR-FRI NGT WITH
LION SHARE FRI-FRI NGT.  WILL LET HWO TAKE CARE OF SNOWFALL POTENTIAL
FOR NOW.  EAST OF DIVIDE...MAIN WX EVENT WILL BE WINDS AND TEMPS WITH
FRONT LIKELY MIXING OUT REMAINING COLD AIR THUR NGT. WILL HAVE TO
WATCH CODY AREA FOR HIGH WIND POTENTIAL THUR NGT AND EARLY FRI AND
WILL ALSO MENTION IN THIS MORNINGS HWO.  AEM

...SATURDAY THROUGH TUESDAY...
ROLLER COASTER TEMPS OVER THE WEEKEND EAST OF THE DIVIDE AS THERMAL
RIDGE PASSES QUICKLY OVER THE STATE SATURDAY...FOLLOWED BY RAPID
RETURN TO MORE SEASONAL TEMPS ON SUNDAY.  WITH STRONG WESTERLY
WINDS SATURDAY WILL DROP MENTION OF PRECIP EXCEPT IN FAR WEST.  WILL
CONTINUE PRESENT FORECAST OF BRINGING SNOW CHANCES ACROSS THE AREA
SATURDAY NIGHT...THEN ONLY MAINLY SW FOR THE WEST TO SOUTHWEST
THROUGH THE REMAINDER OF THE YEAR WITH LITTLE OR NO SNOW FOR CENTRAL
AND NORTH UNTIL 2003.  SULLIVAN

.RIW...NONE.

$$