FXUS65 KRIW 120918
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
215 AM MST FRI MAR 12 2004

.TODAY THROUGH SUNDAY NIGHT...
ONE MORE DRY DAY BEFORE THE SHORTWAVE THAT IS NOW MAKING LANDFALL
ONTO THE BC COAST BEGINS TO AFFECT OUR WEATHER IN OUR NORTHERN ZONES
FRIDAY NIGHT AS THIS SYSTEM HEADS SOUTHEAST. TEMPS TODAY SHOULD BE A
FEW DEGREES WARMER THAN ON THURSDAY WITH THE BASINS/VALLEYS LAGGING A
FEW DEGREES BEHIND. HOWEVER THE BIG HORN BASIN WITH THEIR LACK OF
SNOW COVER SHOULD SEE TEMPS SOAR WELL UP INTO THE 50S TODAY WITH CPR
UP IN THE LOW 50S AS WELL.

THE ETA AND THE GFS ARE MUCH MORE IN AGREEMENT AS FAR AS TIMING GOES
WITH THE ABOVE MENTIONED SHORTWAVE THAN THEY WERE YESTERDAY.
HOWEVER...THE ETA...MUCH LIKE THE 18Z THU RUN...IS ONLY ADVERTISING A
QUICK SHOT OF WEATHER ON SATURDAY AND THE GFS IS EVEN BACKING OFF ON
THE IMPACT OF THIS SHORTWAVE. THE NORTHERN AND EASTERN ZONES OF OUR
CWA STAND THE BEST CHANCE OF RECEIVING MEASURABLE PRECIP AS SOME Q
VECTOR FORCING ALONG WITH GOOD UPPER DIFFLUENT FLOW PRODUCE THE BEST
DYNAMICS THERE ALONG WITH SURFACE CONVERGENCE AS THE ASSOCIATED
STRONG COLD FRONT MOVES SOUTH ACROSS WY SATURDAY MORNING. LOWER
ELEVATIONS OF JOHNSON COUNTY WILL SEE SOME RAIN FROM THIS SYSTEM
FRIDAY NIGHT BEFORE THE CHANGE OVER TO SNOW. AS H7 TEMPS COOL DOWN TO
-19C BY SATURDAY NIGHT IN NE WY...PRECIP TYPE WILL BE ALL SNOW
THEREAFTER. SFC TEMPS WILL ACTUALLY REMAIN STEADY FROM 12Z SAT
THROUGH 18A SATURDAY DURING THE FROPA...ESPECIALLY IN THE NORTHEAST
ZONES. NORTHWEST WINDS WILL GUST UP TO 45 MPH IN JOHNSON COUNTY ONCE
THE POST FRONTAL BORA WIND BECOMES ESTABLISHED THERE SATURDAY EVE.
WESTERLY WIND GUSTS BETWEEN 30 AND 40 MPH WILL OCCUR IN SWEETWATER
COUNTY SATURDAY AFTERNOON BEHIND THE TROUPHPA. EAST OF THE DIVIDE...
SFC WINDS WILL EVENTUALLY GO NORTHERLY FOR A BRIEF PERIOD SATURDAY
EVE BUT WILL BE BRIEF AND SHALLOW SO UPSLOPE ENHANCED PRECIP TOO
SMALL A FACTOR TO AFFECT THE FORECAST.

WARM AIR ADVECTION ALOFT WILL QUICKLY ENSUE SUNDAY CREATING A
STRENGTHENING INVERSION SUNDAY AS A 1037 SFC HIGH BUILDS INTO THE
AREA WHICH WILL ENHANCE PATCHY FOG FORMATION AT LOWER ELEVATIONS OF
THE BIG HORN BASIN LATE SATURDAY NIGHT AND SUNDAY MORNING AFTER SOME
PRECIP MOISTENS THE GROUND THERE SATURDAY. LOWERED TEMPS SUNDAY AND
SUNDAY NIGHT IN THE BASINS.

.MONDAY THROUGH FRIDAY...
FAST WEST TO NORTHWEST UPPER FLOW WILL PERSIST THROUGH THE EXTENDED
PERIOD. AS A RESULT...HAVE MAINTAINED CHANCE POPS FOR MOSTLY THE
WESTERN MOUNTAINS THROUGH PERIOD AS PIECES OF SHORT WAVE ENERGY MOVE
THROUGH THE FLOW AND UP AGAINST MOUNTAINS. EAST OF DIVIDE...DOWNSLOPE
COMPONENT TO KEEP A MOSTLY DRY FORECAST AND LOCALLY BREEZY
CONDITIONS. THIS PERSISTANT PATTERN TO RESULT IN A FAIRLY CONSISTENT
TEMPERATURE PATTERN AS WELL WITH NEAR NORMAL TEMPERATURES.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

LIPSON/TF