Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 242013
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
213 PM MDT TUE MAR 24 2015

.SHORT TERM...TONIGHT THROUGH WEDNESDAY

ACTIVE WEATHER CONTINUES THROUGH MUCH OF THIS PERIOD AS NEXT POTENT
SYSTEM MOVES QUICKLY SE ACROSS THE AREA TONIGHT. SNOW GOT STARTED
QUICKLY THIS MORNING IN THE FAR WEST AS EXPECTED. ADVISORY FOR THE
FAR WEST MOUNTAINS IS LOOKING GOOD WITH A GENERAL 4 TO 8 INCH AMOUNT
FOR MOST OF THE HIGH COUNTRY AND 1 TO 3 INCHES IN THE VALLEYS/LOWER
ELEVATIONS. SHORTWAVE/VORT/JET STREAK SUPPORT MAX BLASTS EAST OF THE
DIVIDE THIS EVENING WITH CONSIDERABLE SNOW AND BLOWING SNOW IN THE
HIGH COUNTRY AND LOTS OF WIND AND AREAS OF SNOW SHOWERS EAST OF
THE DIVIDE...POSSIBLE MIXED WITH RAIN AT FIRST. FEW OF THE WINDIER
SPOTS MAY BE CLOSE TO OR AT HIGH WIND FOR A SHORT TIME WITH FROPA.
WINDS BEND MORE NORTH TONIGHT AS COLD FRONT THEN DROPS DOWN FROM THE
NORTH WITH NICE NW-N CONVERGENCE BOUNDARY AND CYCLONIC SIDE OF THE
JET PUSHES A BAND OF SNOW SWD. LOOKS LIKE A QUICK SHOT OF A SKIFF
TO 2 INCHES UP NORTH WITH A MORE CONCENTRATED BAND WITH SOME
UPSLOPE AROUND CASPER WWD INTO ERN FREMONT. EXPECT 2-3 INCHES IN
THE LOWER ELEVATIONS OF NATRONA COUNTY WITH LOCAL 4 WHERE HEAVIER
SNOW SHOWERS PERIST OR NEAR CASPER MOUNTAIN. 6-9 ON CPR MOUNTAIN. RIW
AND LND ARE ON THE EDGES OF THIS CONVERGENCE AXIS BUT STILL EXPECT
A BAND OF SNOW TO EITHER SAG SWD WITH THE FRONT OR A POTENTIAL
BAND OF SNOW OR TWO TO MOVE SEWD ACROSS THE WIND RIVER BASIN.
COULD ALSO SEE A BRIEF UPSLOPE TOWARDS 12Z TO GIVE LND A COUPLE
HOURS OF SNOW. CONDS IMPROVE QUICKLY IN THE MORNING WITH ENOUGH
INSTABILITY AROUND THROUGH THE MORNING TO KEEP SOME SNOW SHOWERS
OVER AND NEAR THE MOUNTAINS BEFORE DECREASING AS SOME MID LEVEL
WARMING STABILIZES THE ATMOSPHERE A LITTLE IN THE AFTERNOON.

.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY

WEDNESDAY NIGHT THROUGH TUESDAY

BEGINNING OF FCST...RIDGE ACROSS THE WRN CONUS...WITH SW TROF THRU
AND RELATIVELY COLD NW FLOW ALOFT...WHILE THE AREA IS POST FRONTAL
AT THE SFC. UNSTABLE BUT DECREASING SHOWERY CONDITIONS PREVAILING
EARLY...MAINLY E OF THE DIVIDE. THEN BY SUN-UP THU MORNING...THE NEXT
UPR LVL DISTURBANCE FLIES SWD...SKIMMING ERN WY AND DRAGGING A
SECONDARY CLIPPERISH FRONT THRU THE FA...AGAIN E OF THE DIVIDE.
AVAILABLE MOISTURE WILL BE ON THE DECREASE AS THE WRN RIDGE BEGINS
TO TRANSLATE EWD AS THIS SMALL SYSTEM MOVES THRU...SHUNTING BETTER
MOISTURE OFF TO THE E. STILL...CHC OR BETTER POPS NRN
MOUNTAINS...SLIGHT TO CHC E OF THE DIVIDE AT LOWER ELEVATIONS WITH
ALL POPS DECREASING QUICKLY BY THU NIGHT.

RIDGING AND WARMING TREND THRU SAT BEFORE NEXT SYSTEM HEADS INTO
THE REGION OVERNIGHT. THIS ALSO COINCIDES WITH A BREAKDOWN IN WHAT
WAS FAIRLY GOOD SPATIAL CORRELATION BETWEEN THE LR MDLS TO THAT
POINT. REALLY COMES DOWN TO WHAT TO DO WITH AN INCOMING AND FAIRLY
VIGOROUS EPAC TROF AS IT PLOWS INTO THE RIDGE FROM THE WEST. AS IT
FALLS APART...WHERE WILL THE DEEPEST PART OF THE UPR LOW SET-UP.
OTHERWISE...AS THE TREND IS TO KEEP UPR LVL NW FLOW AROUND THE
REGION EXCEPT FOR A COUPLE OF SHORT INTERMITTENT BLIPS...AND SINCE
TIMING DOES NOT SEEM TO BE THAT MUCH OF AN ISSUE...HAVE STAYED WITH
THE IDEA OF KEEPING THE FA...QUOTE... UNSETTLED...UNQUOTE THRU THE
END OF THE FCST PERIOD...WHEN PERHAPS THE BEST CHANCE FOR NEW
PRECIP/SNOW ACROSS THE AREA COMES TOGETHER MORE
COHESIVELY.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

A NEW STORM SYSTEM WILL BRING ANOTHER ROUND OF RAIN AND SNOW SHOWERS
THROUGH THE REMAINDER OF THE AFTERNOON INTO EARLY EVENING WITH
LOWERING SNOW LEVELS AND A VERY STRONG WEST WIND. A COLD FRONT WILL
THEN DROP SWD OVERNIGHT WITH FQT SNOW SHOWERS BEHIND IT...ESPECIALLY
AFTER 03Z IN THE NORTH AND 06Z-09Z IN THE CENTRAL AREAS INCLUDING
KCPR...KRIW AND EVENTUALLY KLND. EXPCT MVFR TO LCL IFR CONDS BEHIND
THE FRONT DUE TO LOW CIGS AND SNOW SHOWERS. CONDS WILL IMPROVE FROM
NORTH TO SOUTH IN THE MORNING WITH SNOW SHOWERS RETREATING TO MAINLY
THE HIGH COUNTRY BY MID MORNING WEDNESDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

ANOTHER POTENT STORM SYSTEM WILL IMPACT THE WEST MUCH OF THE NIGHT
BUT WITH SOME IMPROVEMENT AFTER MIDNIGHT AT LEAST IN TERMS OF
SNOWFALL. WIDESPREAD SNOW SHOWERS AND INCREASING WEST WIND CAN BE
EXPECTED ACROSS THE WEST THROUGH THIS EVENING BEFORE CONDS SLOWLY IMPROVE.
EXPECT ISOLATED THUNDERSTORMS IN THE NORTHWEST CORNER INCLUDING
AROUND KJAC THROUGH 01Z. EXPECT MVFR TO IFR CONDITIONS AND FREQUENT
MOUNTAIN OBSCURATION. THE KJAC TERMINAL WILL BE IFR MOST OF THE TIME
THROUGH 03Z THIS EVENING BEFORE CONDS IMPROVE TO MVFR.

AT KRKS AIRPORT...VERY WINDY CONDITIONS UNTIL 02Z WITH SCT SNOW
SHOWERS...THEN A SLOW DECREASE IN WIND AND SNOW SHOWERS AFTER 02Z.
VFR CONDS ARE EXPECTED WEDNESDAY BUT WITH A MORNING CIG AROUND 040.

KPNA AIRPORT WILL SEE FQT SNOW SHOWERS WITH MVFR TO BRIEF IFR CONDS
THRU EARLY EVENING BEFORE CONDS SLOWLY IMPROVE OVERNIGHT. VFR CONDS
ARE EXPECTED AFTER MIDNIGHT AND THROUGH WEDNESDAY BUT WITH A CIG
AROUND 040 INTO THE MORNING HOURS WEDNESDAY.

&&

.FIRE WEATHER...

A NEW WEATHER SYSTEM WILL BRING CONSIDERABLE WIND AND SNOW SHOWERS
TO MUCH OF THE AREA INTO TONIGHT AND EAST OF THE DIVIDE INTO
WEDNESDAY MORNING. MANY AREAS WILL SEE WEST TO NORTHWEST WIND OF 20
TO 30 MPH WITH GUSTS OF 40 TO 50 MPH INTO THIS EVENING. WINDS WILL
NOT BE AS STRONG ON WEDNESDAY BUT GUSTY WEST TO NORTHWEST WIND IS
STILL EXPECTED IN THE SOUTH. IT WILL BE COOL ON WEDNESDAY WITH HIGHS
IN THE 30S AND 40S WITH MIN RH`S GENERALLY IN THE 30S AND 40S EXCEPT
BRIEFLY IN THE 20S IN THE SOUTHWEST.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 3 AM TO 9 AM MDT WEDNESDAY
WYZ020-022.

WINTER WEATHER ADVISORY UNTIL 3 AM MDT WEDNESDAY
WYZ001-002-012-024.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 9 AM MDT
WEDNESDAY WYZ008-009.

&&

$$

SHORT TERM...SKRBAC
LONG TERM...BRAUN
AVIATION...SKRBAC
FIRE WEATHER...SKRBAC







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