Weather Service Report


504 
FXUS65 KRIW 262058
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
158 PM MST MON JAN 26 2015

.SHORT TERM...TONIGHT THROUGH TUESDAY

MAINLY TRANQUIL WEATHER WILL BE THE RULE THROUGH THE SHORT TERM. BY 
AS ALWAYS...THERE ARE A COUPLE OF THINGS CAUSING PROBLEMS...IT WOULD 
NOT BE WYOMING WEATHER WITHOUT IT. FIRST IS IN THE WESTERN VALLEYS 
WHERE SOME FOG HAS STUCK AROUND MOST OF THE MORNING. IT HAS LIFTED 
IN THE JACKSON VALLEY...BUT HAS PERSISTED IN THE STAR VALLEY. 
HOWEVER...IT IS RATHER PATCHY AND HARD TO PINPOINT. IN 
ADDITION...INVERSIONS ARE STILL PRESENT ACROSS THE DEEPER BASINS 
EAST OF THE DIVIDE. CASE IN POINT...AT NEAR NOON WE ARE SITTING AT 
38 AT THE HUMBLE RIVERTON WEATHER ABODE. MEANWHILE...ABOUT 35 MILES 
UP THE ROAD AT CROWHEART IT IS 61...ABOUT A DEGREE FOR EVERY MILE 
AND A HALF. AROUND NOON...THERE WAS A 46 DEGREE DIFFERENCE ACROSS 
THE COUNTY WARNING AREA. FOR TONIGHT...IT LOOKS LIKE A REPEAT WITH 
MORE FOG IN THE WESTERN VALLEYS WITH MAINLY TRANQUIL WEATHER 
ELSEWHERE. WE CAN NOT RULE OUT FOG IN SPOTS EAST OF THE DIVIDE...BUT 
THIS WOULD BE THE EXCEPTION RATHER THAN THE RULE. 

ON TUESDAY...A SYSTEM MOVING UP FROM ARIZONA WILL MAKE ITS WAY 
TOWARD THE COWBOY STATE. CLOUDS WILL INCREASE FROM THE WEST IN THE 
AFTERNOON AS IT APPROACHES. ANY CHANCE OF PRECIPITATION WOULD BE 
CONFINED TO FAR WESTERN AREAS DURING THE DAYLIGHT HOURS. AND EVEN 
HERE...THE MORNING LOOKS DRY WITH MOST AREAS REMAINING DRY FOR A 
VAST MAJORITY OF THE DAY. THERE WILL BE MORE ON THE SNOW POTENTIAL 
IN THE LONG TERM DISCUSSION FROM MY ESTEEMED COLLEAGUE. 
MEANWHILE..EAST OF THE DIVIDE IT LOOKS LIKE ANOTHER DRY WITH MILD 
TEMPERATURES. ONCE AGAIN...BASINS WILL BE COOLER WITH THE EVER 
PRESENT INVERSIONS. THERE WILL BE AN INCREASE IN HIGH CLOUDS IN THE 
AFTERNOON HOWEVER. IN ADDITION...SOUTHWEST FLOW AND THE PRESSURE 
GRADIENT TIGHTENING A BIT WILL BRING GUSTY TO WINDS TO AREAS AROUND 
NATRONA COUNTY. AT THIS TIME...UPPER LEVEL WINDS DO NOT LOOK STRONG 
ENOUGH FOR ANY WIND HIGHLIGHTS...BUT SOMETHING TO WATCH.

.LONG TERM...TUESDAY NIGHT THROUGH MONDAY

UPPER LOW OFF THE CALIFORNIA COAST BECOMES ARE MAIN WEATHER MAKER 
FOR TUESDAY NIGHT AND WEDNESDAY AS IT STARTS TO SHEAR APART AND THE 
NRN PART MOVES INTO WRN WYO BY TUESDAY EVENING CONTINUING INTO 
WEDNESDAY MORNING. AS THIS PIECE OF ENERGY CROSS THE DIVIDE IN NWRN 
WYOMING LATE TUESDAY NIGHT IT LOOKS LIKE IT WILL TRACK THRU SERN WYO 
WITH A SWATH OF LIGHT RAIN/SNOW QUITE POSSIBLE. A FRONTAL BOUNDARY 
IN THE NORTH AND EAST MAY ALSO HELP TO FOCUS THIS. LIKED THE IDEA OF 
SWATCH FROM THE BIGHORN BASIN AREA TO CASPER ON WEDNESDAY AND DIDN'T 
CHANGE THAT. DID ADD A LITTLE NEAR THE MT BORDER EARLY WEDNESDAY. 
SNOWFALL AMOUNTS STILL LOOK GENERALLY SUB-ADVISORY BUT IT DOESN'T 
TAKE MUCH TO GET 3 INCHES OR MORE IN PLACES LIKE THE STAR VALLEY SO 
WE'LL JUST HAVE TO WATCH THAT. A FEW OF THE MOUNTAIN LOCALES COULD SEE 
ADVISORY AMOUNTS BUT OVERALL IT'LL PROBABLY BE A MORE 3 TO 6 INCH 
TYPE EVENT TUESDAY NIGHT AND WEDNESDAY MORNING. NEXT SYSTEM WHICH IS 
JUST A LITTLE FURTHER WEST IN THE PACIFIC FROM THE ONE JUST OFFSHORE 
CALIFORNIA THEN MOVES ONSHORE THURSDAY AND INTO THE DESERT SW 
THURSDAY NIGHT INTO FRIDAY. MOISTURE AHEAD OF THIS ON WEAK NEWD 
MOVING RIPPLES MAY SPREAD A LITTLE LIGHT QPF INTO THE FAR S OR SW 
THURSDAY NIGHT INTO FRIDAY. THE GFS IS MOST BULLISH WITH THIS IDEA 
WHILE THE NAM AT 84HRS AND THE ECMWF AT 84 AND BEYOND KEEPS MOST OF 
IT TO THE SOUTH. LIKE THE IDEA OF SOME LOW POPS MAINLY IN THE FAR S 
AND SW THURSDAY NIGHT THROUGH FRIDAY. LATE FRIDAY OR FRIDAY NIGHT A 
SHORTWAVE DROPS DOWN INTO THE NRN HIGH PLAINS WITH A COLD FRONT 
PUSHING INTO AT LEAST FAR NRN OR NERN ZONES. 12Z ECMWF HAS BACKED 
OFF ON A STRONGER PUSH WHICH PRODUCED A LITTLE UPSLOPE. KEEPING 
PREVIOUS IDEA OF MAINLY SLIGHT CHANCES IN THE MOUNTAINS. ANOTHER 
CLIPPER MAY JUST NICK THE FAR N AND NERN ZONES ABOUT SATURDAY NIGHT 
SO PUT IN SOME SLIGHT CHANCES FOR JOHNSON COUNTY BESIDES KEEPING THE 
MTN POPS. THE GEM IS MUCH STRONGER AND FURTHER WEST WITH THIS 
SHORTWAVE AND ASSOCIATED FRONT. LOOKS LIKE FLOW STARTS TO FLATTEN AT 
THE END OF THE MEDIUM RANGE PERIOD WITH POTENTIAL FOR INCREASING 
WIND EAST OF THE DIVIDE AND SNOW IN THE W OR NW. 
&&

.AVIATION.../XXZ ISSUANCE/

VFR CONDITIONS WILL PREVAIL OVER THE REGION THROUGH TUESDAY 
AFTERNOON. THE EXCEPTION WILL BE THE DEEPER WESTERN VALLEYS WHERE 
THERE WILL BE AREAS OF LOW CLOUDS AND FOG THROUGH 
TONIGHT...INCLUDING AT KJAC INTO TUESDAY MORNING. GUSTY SOUTHWEST 
WINDS WILL CONTINUE AT KCPR THROUGH THE PERIOD. SOME LIGHT
PRECIPITATION WILL SPREAD NORTHWARD INTO THE WESTERN MOUNTAINS
AFTER 20Z TUESDAY BUT ALL TAF SITES SHOULD REMAIN PRECIPITATION
FREE THROUGH 00Z WEDNESDAY.&&

.FIRE WEATHER...

INVERSIONS WILL CONTINUE ACROSS THE WESTERN VALLEYS AS WELL AS SOME 
OF LOWER BASINS EAST OF THE DIVIDE INTO TOMORROW...RESULTING IN LOW 
MIXING HEIGHTS AND POOR SMOKE DISPERSAL. GUSTY SOUTHWEST WINDS WILL 
CONTINUE FROM THE RED DESERT THROUGH NATRONA COUNTY THROUGH TUESDAY. 
A SYSTEM APPROACHING FROM THE SOUTH WILL SPREAD SOME SNOW INTO THE 
WESTERN MOUNTAIN ON TUESDAY NIGHT AND WEDNESDAY. 
&&

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

$$

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



Return to Home page


Western Regional Climate Center, wrcc@dri.edu