804 
FXUS65 KRIW 112146
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
246 PM MST WED FEB 11 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 211 PM MST WED FEB 11 2015

TONIGHT-THURSDAY: 
LATEST WATER VAPOR LOOP WAS SHOWING THE UPPER LEVEL RIDGE
CONTINUING TO DOMINATE THE REGION. HOWEVER...THERE IS SOME CIRRUS
BEGINNING TO SPILL OVER THE RIDGE WHICH IS EXPECTED TO MOVE OVER
THE AREA BEGINNING TONIGHT AND CONTINUING THROUGH TOMORROW. THIS
MAY TEND TO RESTRICT TEMPERATURES A BIT TOMORROW...BUT IT SHOULD
STILL BE A NICE DAY WITH FAIRLY LIGHT WIND SPEEDS. WE MAY STILL
NEED TO CONTEND WITH SOME VALLEY FOG...BUT THE CIRRUS WILL TEND TO
LIMIT THAT POTENTIAL. 

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 211 PM MST WED FEB 11 2015

THURSDAY NIGHT-FRIDAY NIGHT:
NO SIGNIFICANT CHANGES ARE PLANNED THROUGH THIS PERIOD EITHER WITH
MILD TEMPERATURES AND LIGHT WIND SPEEDS CONTINUING DUE TO THE
INFLUENCE OF THE UPPER LEVEL RIDGE IN ROCKIES. WE MAY SEE ENOUGH
MOISTURE AND UPSLOPE FLOW TO GENERATE A FEW RAIN OR SNOW SHOWERS
IN YELLOWSTONE OR THE TETONS...BUT NOT EXPECTING ANYTHING MORE
THAN A DUSTING. 

SATURDAY-WEDNESDAY:
THINGS BECOME A LOT MORE ACTIVE AS WE APPROACH SUNDAY INTO SUNDAY
NIGHT. THIS IS DUE TO A STRONG JET DIGGING SOUTH FROM BRITISH
COLUMBIA. MEANWHILE...ANOTHER STRONG UPPER LEVEL JET IN THE
NORTHERN PLAINS BEGINS TO DEPART THE REGION SUNDAY AFTERNOON INTO
SUNDAY NIGHT. THIS DEPARTING JET WILL PUT US UNDER THE INFLUENCE
OF THE RIGHT ENTRANCE REGION OF THE UPPER LEVEL JET BEGINNING
SUNDAY AFTERNOON. THERE WILL BE SOME WEAK CONDITIONAL INSTABILITY
IN THE MOUNTAINS...BUT THERE COULD BE SOME GOOD INERTIAL
INSTABILITY IN THE SOUTHERN HALF OF THE FORECAST AREA WHICH MAY
PROMOTE SOME WIDELY SCATTERED RAIN SHOWERS SUNDAY AFTERNOON. THE
MAIN SHOW IS PROGGED TO SETUP SUNDAY NIGHT INTO MONDAY MORNING AS
THE COLD FRONT BEGINS TO MOVE THROUGH THE AREA. IT APPEARS TO BE
ENOUGH LIFT TO PRODUCE SOME WIDESPREAD SNOW ESPECIALLY IF WE CAN
GET INFLUENCED BY A COUPLED JET SCENARIO. OTHERWISE...MUCH COLDER
AIR WILL BEGIN TO SETTLE INTO THE REGION ON MONDAY NIGHT INTO
TUESDAY AS THE ARCTIC HIGH MOVES IN. IN FACT...HIGHS MAY STRUGGLE
TO GET OUT OF THE TEENS ON TUESDAY WITH OVERNIGHT LOWS DROPPING
BELOW ZERO IN SOME OF THE VALLEYS TUESDAY NIGHT INTO WEDNESDAY
MORNING. 


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1037 AM MST WED FEB 11 2015

PATCHY DENSE FOG IN THE VALLEY CONTINUES TO PLAGUE THE KCOD TAF
SITE THIS MORNING. THIS IS DUE TO GOOD UPVALLEY FLOW WHICH IS
CONTRIBUTING TO THE FOG. WE ARE NOT REAL CONFIDENT WHEN THIS FOG
WILL ERODE...BUT WE DID NOTICE THE VISIBILITY WAS TRYING TO
IMPROVE DURING THE LAST HOUR. HOWEVER...THE HRRR WAS CONTINUING TO
SHOW THE UPVALLEY FLOW CONTINUING DURING THE NEXT COUPLE OF HOURS.
AS A RESULT...WE WENT AHEAD AND KEPT THE VISIBILITY LOW THROUGH
ABOUT 20Z OR SO. MEANWHILE...THE KJAC/KRKS TAF SITES ARE SHOWING
MVFR CEILINGS BUT THESE CEILINGS IMPROVE PRETTY QUICKLY. THE REST
OF THE TAF SITES VFR CONDITIONS SHOULD PREVAIL WITH MAINLY LIGHT
AND VARIABLE WINDS. &&


.FIRE WEATHER...
ISSUED AT 211 PM MST WED FEB 11 2015

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA AND BRING MAINLY 
DRY AND MILD WEATHER THROUGH SATURDAY. TEMPERATURES WILL BE WELL
ABOVE NORMAL FOR THURSDAY AND FRIDAY. A GUSTY BREEZE WILL BLOW AT
TIMES ACROSS THE SOUTHWESTERN WIND CORRIDOR AND EAST OF THE
ABSAROKAS. RELATIVE HUMIDITY WILL LOWER SUBSTANTIALLY FOR THURSDAY
BUT WILL REMAIN ABOVE RED FLAG CRITERIA. 

&&

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

$$

SHORT TERM...COX
LONG TERM...COX 
FIRE WEATHER...COX