Area Forecast Discussion
Issued by NWS Riverton, WY

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
000
FXUS65 KRIW 271754
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1155 AM MDT WED APR 27 2016

.SHORT TERM...WEDNESDAY THROUGH FRIDAY NIGHT

WE WILL BE IN A 3C TYPE OF PATTERN THROUGH THE REMAINDER OF THE
WEEK. FOR THOSE THAT DO NOT KNOW...THIS MEANS CLOUDY...COOL AND
CRUDDY. EARLY THIS MORNING...WE HAVE ONE OF THOSE ANNOYING SNOW
BANDS THAT HAS POPPED UP WITH THE UNSTABLE NORTH TO NORTHWEST FLOW.
ANOTHER THING FEEDING THIS IS A STREAM OF MOISTURE WRAPPING BACK
AROUND THAT SHOWS UP WELL ON SATELLITE IMAGERY.THE SNOW IS HAVING
TROUBLE STICKING TO MOST PAVED SURFACES THOUGH. ALL THE MODELS DO
SHOW A DECREASE IN PRECIPITATION THROUGH THE MORNING THOUGH. BUT
WITH THE UNCERTAINTY WITH THE UPPER LEVEL LOW...THEY DO NOT CALL
THEM UPPER LEVEL DEVILS FOR NOTHING...WE HAVE KEPT SLIGHT CHANCE
TO CHANCE POPS IN THE FORECAST ALL DAY FOR MOST AREAS TO ACCOUNT
FOR THE UNCERTAINTY OF ANY RAIN. HOWEVER...IT DOES LOOK MUCH LESS
ORGANIZED AND HEAVY THAN YESTERDAY. THERE COULD BE MORE SNOW IN
THE MORNING...BUT MUCH LIKE YESTERDAY WITH THE HIGH LATE APRIL SUN
IT WILL HAVE A HARD TIME STICKING. EXPECT MORE OF THE SAME TONIGHT
WITH ADDITIONAL SHOWERS. THERE COULD BE A BIT MORE ORGANIZED
ACTIVITY IN NORTHERN JOHNSON COUNTY TONIGHT AS A SPOKE OF ENERGY
AND MOISTURE BACKS IN THE AREA FROM THE EAST. MOST SHOULD REMAIN
IN MONTANA THOUGH. PREVIOUS POPS LOOKED FAIRLY GOOD...SO WE MADE
FEW CHANGES.

THURSDAY AND FRIDAY LOOK VERY MUCH THE SAME WITH A TROUGH AND
CYCLONIC CURVATURE REMAINING OVER THE ROCKIES AND KEEPING THE
UNSETTLED AND COOL WEATHER THROUGH THE PERIOD. STILL SOME SHOWERS
THURSDAY POSSIBLE ON THURSDAY ALTHOUGH PINPOINTING THEM IS
IMPOSSIBLE AT THIS TIME. THE MODELS ARE SHOWING SOME MOISTURE
POSSIBLY CREEPING INTO SOUTHERN SWEETWATER COUNTY AS THE NEXT UPPER
LEVEL LOW PASSES TO THE SOUTH SO WE BUMPED UP POPS A BIT IN THAT
VICINITY. EXPECT MORE OF THE SAME FOR FRIDAY. LATER FRIDAY NIGHT
COULD GET MORE INTERESTING AS LEE CYCLOGENESIS TAKES PLACE OVER
COLORADO. THE MODELS ARE BEGINNING TO SHOW SOME MOISTURE WRAPPING
BACK INTO THE AREA WITH UPSLOPE FLOW DEVELOPING. AT THIS TIME...IT
LOOKS MORE LIKE SATURDAY THAN FRIDAY NIGHT WOULD BE THE BEST CHANCE
FOR ANY SIGNIFICANT PRECIPITATION. MY ESTEEMED COLLEAGUE WILL HAVE
MORE ON THAT HOWEVER.

.LONG TERM...SATURDAY THROUGH WEDNESDAY

GLOBAL MODELS ARE IN GOOD AGREEMENT WITH AN UPPER LOW OVER NE CO/W
NE...AND ONE FARTHER WEST IN NORTHERN UTAH AT 12Z SATURDAY. THE
FORMER ONE IS EXPECTED TO REMAIN NEARLY STATIONARY OR RETROGRADE
NORTHWEST INTO THE COWBOY STATE SAT/SAT NIGHT...WHILE THE OTHER
UPPER LOW DIGS SOUTHWARD INTO THE DESERT SOUTHWEST. BOTH THE GFS AND
ECMWF SHOW A MOIST EASTERLY/NORTHEAST FLOW SATURDAY/SATURDAY
NIGHT...ESPECIALLY EAST OF THE DIVIDE. HAVE INCREASED POPS...AND
LOWERED TEMPERATURES A TAD. 700MB TEMPERATURES COOL TO BETWEEN -5
AND -7C OVER THE EAST SATURDAY WHICH WOULD TRANSLATE A RAIN/SNOW
LINE BETWEEN 5000 AND 6000 FEET. AREAS OVER THE FAR WEST WILL BE
WARMER WITH THE POSSIBILITY OF MORE SHOWERY CONDITIONS WITH EVEN
SHOT OF AN ISOLATED THUNDERSTORM. INCLEMENT WEATHER AND COOL
CONDITIONS CONTINUE INTO SUNDAY...WITH THE GFS WETTER THAN THE
ECMWF...AS THE GFS ROTATES THE UPPER LOW WESTWARD ACROSS THE AREA.
HOWEVER THE PRECIPITATION ON SUNDAY LOOKS TO BE LIGHTER THAN WHAT
OCCURS SAT/SAT NIGHT...WITH AN EMPHASIS EAST OF THE DIVIDE.

BY SUNDAY NIGHT/MONDAY...MODELS ARE SHOWING A PSEUDO REX BLOCK
DEVELOPING OVER WESTERN NORTH AMERICA...WITH AN UPPER RIDGE OVER
SW CANADA...AND A BROAD UPPER LOW OVER THE WESTERN U.S. THE BROAD
UPPER LOW CENTERED ROUGHLY OVER UTAH WILL KEEP CHANCES OF
PRECIPITATION ACROSS THE AREA AS WEAK DISTURBANCE ROTATE AROUND
THIS UPPER LOW. THE LARGE UPPER LOW...WEAKENS AND GETS SHEARED OUT
MONDAY NIGHT/TUESDAY...BEFORE BOTH MODELS SHOW THE POTENTIAL FOR
STRONG UPPER RIDGING OVER THE AREA WEDNESDAY. TUESDAY STILL COULD
SEE SOME CONVECTION...BEFORE DRIER AIR AND MORE STABLE AIR WORKS
INTO THE AREA WEDNESDAY.

TEMPERATURES WILL BE BELOW TO MUCH BELOW AVERAGE THIS WEEKEND...WITH
A WARMING TREND NEXT WEEK...WITH SEASONAL TEMPS EXPECTED BY
TUESDAY/WEDNESDAY.

&&

.AVIATION.../18Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

SCT SHRA AND POSSIBLY AND ISOLD TS WILL SPREAD INTO THE SW...UP TO A
VCNTY KPNA-KRKS LINE...IN THE AFTERNOON.  MOST OF THIS ACTIVITY
SHOULD DISSIPATE WITH SUNSET.  SFC NE WINDS WILL INCREASE ACROSS THE
INTERSTATE 80 CORRIDOR...KRKS...TONIGHT WITH SOME LOWER MVFR CIGS
POSSIBLY DEVELOPING FROM VCNTY KRKS TO SOUTH PASS AND EASTWARD.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

LCL MVFR CIGS ARE EXPECTED TO LIFT THROUGH 19Z. CIGS WILL LIFT TO
PREVAILING VFR IN THE AFTERNOON WITH SNOW SHOWERS CONTINUING TO
PARTIALLY OBSCURE HIGHER MTNS.  UPSLOPE FLOW WILL RETURN WEDNESDAY
EVENING ALONG WITH DEVELOPMENT OF LOWER MVFR CIGS 4Z-12Z THURSDAY.

&&

.FIRE WEATHER...

FEW CONCERNS FOR MOST OF THE WEEK WITH UPPER LEVEL LOW PRESSURE
KEEPING THE WEATHER UNSETTLED. TEMPERATURES WILL AVERAGE BELOW
NORMAL WITH RELATIVE HUMIDITY REMAINING ABOVE CRITICAL LEVELS...SOME
AREAS WELL ABOVE CRITICAL LEVELS. THERE WILL BE A DAILY CHANCE FOR
SHOWERS FROM TODAY LIKELY INTO THE WEEKEND FOR MANY AREAS.

&&

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

&&

$$

SHORT TERM...HATTINGS
LONG TERM...WM
AVIATION...AEM/LIPSON
FIRE WEATHER...HATTINGS



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.