Strong westerly flow ahead of an approaching Pacific storm produced heavy snowfall in the mountains of far west Wyoming. Snowfall around Jackson Hole ranged from about 3 inches in Jackson to 13 inches at Moose.
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The episode as NWS RIW wrote it up.
Strong westerly flow ahead of an approaching Pacific storm produced heavy snowfall in the mountains of far west Wyoming. Snowfall around Jackson Hole ranged from about 3 inches in Jackson to 13 inches at Moose. The nearby Teton Range and the higher terrain of Yellowstone National Park received 10 to 16 inches of snow. The exceptions were a few measuring sites at the Jackson Hole Mountain Resort which measured snowfall of 17 to 19 inches.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Riverton, WY wrote its last area forecast discussion before the first event at Mar 28, 2:00 AM MST, 8 hours earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 300 AM MDT SAT MAR 28 2009 .SHORT TERM...TODAY THROUGH MONDAY NIGHT SNOWFALL OVER JACKSON VALLEY TAPERED OFF LATE LAST EVENING...WITH GENERALLY BENIGN CONDITIONS FOUND OVER CENTRAL AND WESTERN WYOMING THIS MORNING. SOME HIGH AND MID LEVEL CLOUDS ARE PRESENT OVER NATRONA AND SWEETWATER COUNTIES...AND LOWER CLOUD COVER CONTINUES TO LINGER OVER JACKSON VALLEY. CONTINUED WARMING TEMPERATURES EXPECTED TODAY ACROSS THE CWA UNDER A NORTHWEST FLOW. SATELLITE DEMONSTRATES ADDITIONAL CLOUD COVER UPSTREAM THIS MORNING. THIS ADDED MOISTURE WILL IMPACT THE WESTERN MOUNTAINS AND VALLEYS TODAY...WITH SNOWFALL POSSIBLE ESPECIALLY OVER THE FAVORED AREA OF SOUTHWESTERN YELLOWSTONE NATIONAL PARK AND OVER THE TETON MOUNTAINS. ANOTHER SIGNIFICANT STORM SYSTEM WILL REMAIN ON THE HEELS OF ARRIVING MOISTURE THIS AFTERNOON. AS THE TROUGH OF LOW PRESSURE MOVES OFF THE PACIFIC COAST SATURDAY EVENING...IT WILL PUSH CONTINUED MOISTURE OVER WESTERN WYOMING. A ZONAL FLOW WILL SET UP BY SUNDAY MORNING AS THE SYSTEM PUSHES FURTHER INLAND. FLOW WILL SHIFT TO THE SOUTHWEST DURING LATE MORNING HOURS OF SUNDAY AS THE TROUGH BECOMES A CLOSED LOW PRESSURE SYSTEM. THE AXIS OF THIS SYSTEM WILL MOVE THROUGH CENTRAL IDAHO SUNDAY AFTERNOON AS IT ADVANCES EAST TOWARDS WYOMING. FOR NOW...MODELS INDICATING THAT WESTERN WYOMING WILL HAVE THE POTENTIAL FOR 6 TO 12 INCHES OF SNOWFALL THROUGH SUNDAY EVENING. HIGHLIGHTS ASSOCIATED WITH THIS SNOWFALL WILL BE DELAYED UNTIL LATER SHIFTS TO ENSURE STRENGTH OF THE SYSTEM. TEMPERATURES WEST OF THE DIVIDE WILL CONSEQUENTLY BE COOLER ON SUNDAY...AND HIGH TEMPERATURES EAST OF THE DIVIDE WILL FADE WITH THE PASSAGE OF A COLD FRONT SUNDAY EVENING. MODELS INDICATING THE LOW PRESSURE SYSTEM WILL MOVE OVER NORTHERN WYOMING BEGINNING SUNDAY EVENING...AND WILL CONTINUE TO PUSH EAST THROUGH MONDAY ENDING UP OVER THE WYOMING...SOUTH DAKOTA AND NEBRASKA BORDERS BY MONDAY AFTERNOON. SIGNIFICANT SNOWFALL WILL BE POSSIBLE OVER THE BIG HORN BASIN...BIGHORN MOUNTAINS...THE LOWER ELEVATIONS OF HOT SPRINGS...SOUTHERN JOHNSON...AND NATRONA COUNTIES THROUGH THE DAY ON MONDAY. HAVE ISSUED A WINTER STORM WATCH EFFECTIVE FROM SUNDAY EVENING THROUGH MONDAY AFTERNOON FOR THESE AREAS. SNOWFALL OVER THE LOWER ELEVATIONS MAY BE BETWEEN 4 AND 8 INCHES...WITH THE HIGHER ELEVATIONS SEEING POTENTIAL SNOWFALL OF 10 TO 15 INCHES. ADDITIONALLY...MODELS INDICATING STRONG NORTHWEST WINDS TO FORM OVER NORTHERN JOHNSON COUNTY DURING THE SAME TIME FRAME...WITH WINDS OF 35 TO 40 MPH WITH GUSTS OF 50 MPH WILL BE POSSIBLE DURING THE MORNING AND EARLY AFTERNOON HOURS. THESE WINDS COUPLED WITH PERIODS OF POTENTIALLY HEAVY SNOWFALL HAVE LED TO THE ISSUANCE OF A BLIZZARD WATCH FOR NORTHERN JOHNSON COUNTY. PLEASE SEE THE WINTER STORM PRODUCTS...WSWRIW...FOR FURTHER DETAILS REGARDING THIS POTENTIALLY SIGNIFICANT SNOWSTORM. SNOWFALL AND WINDS WILL WEAKEN MONDAY EVENING AS THE AREA OF LOW PRESSURE MOVES EAST OF THE CWA AND ANOTHER ROUND OF NORTHWEST FLOW MOVES OVER THE CWA. TEMPERATURES ON MONDAY WILL BE COOLER...WITH AREAS EAST OF THE DIVIDE ONLY REACHING INTO THE LOW TO MID 30S. .LONG TERM...TUESDAY THROUGH SATURDAY MODEL DIFFERENCES CONTINUE TONIGHT THE TUESDAY...WEDNESDAY SYSTEM. THE GFS IS STRONGER WITH THE SHORTWAVE THAT RIDES DOWN IN THE STRONG NW FLOW BUT BOTH MODELS SHOW PLENTY OF MOUNTAIN SNOWFALL AND PCPN ACROSS AT LEAST THE NRN ZONES. THE GFS WOULD WARRANT HIGHER POPS FURTHER SOUTH WITH ITS DIGGING SHORTWAVE AXIS PASSING RIGHT THROUGH THE AREA WED MORNING. WILL LEAVE THE LIKELY POPS IN THE NW TUESDAY...SPREADING TO ALL OF THE WEST AND NORTH TUESDAY NIGHT AND WEDNESDAY WITH CHANCE POPS ELSEWHERE. STRONG 150KT JET MAY ALSO PROVIDE SOME LEFT EXIT OR CURVED NOSE JET STREAK DIVERGENCE TUESDAY NIGHT ALONG WITH MODERATE QG AND FRONTAL FORCING. BRISK NW FLOW PREVAILS WEDNESDAY NIGHT AND THURSDAY WITH ISENTROPIC UPGLIDE AND AT LEAST CHANCE POPS WARRANTED ACROSS THE MTNS. THE NRN ZONES MAY ALSO SEE SOME LIGHT RAIN OR SNOW IN THIS PATTERN. NEXT TROUGH BEGINS TO SLOWLY DIG INTO THE CENTRAL ROCKIES OVER EVEN NRN GREAT BASIN. THE ECMWF IS FURTHER SW WITH THE TROUGH DEVELOPMENT OVER UTAH WHILE THE OPERATIONAL GFS HAS THE ELONGATED TROUGH DIGGING THROUGH WYOMING AND DOWN INTO NRN UT BY FRIDAY EVENING. WILL SHOW INCREASING POPS FROM WEST TO EAST FRIDAY INTO FRIDAY NIGHT AND CONTINUING INTO SATURDAY BEFORE GRADUALLY SHIFTING TO THE SERN ZONES SATURDAY NIGHT. LEANED MORE TOWARDS THE ECMWF ON SATURDAY AND SATURDAY NIGHT. TEMPERATURES WILL BE A LITTLE TRICKY WITH RAPID TRANSITION FROM ONE SYSTEM TO THE NEXT. GFS IS COLDER THROUGHOUT WHILE THE ECMWF HAS A COUPLE WARMER DAYS IN BETWEEN STORMS. FORECAST IS A COMPROMISE EARLY ON AND THEN LEANING TOWARD THE ECMWF BY THE END OF THE PERIOD. && .AVIATION... EXPECT LOWERING CIGS AND INCREASING SNOWFALL WEST OF THE DIVIDE TODAY WITH PREVAILING MVFR CONDITIONS/LOCAL VCNTY KJAC AND THE FAR WEST AFTER 20Z AND PREVAILING IFR/LIFR CONDITIONS AFTER 29/01Z. AREAS OF MVFR AND -SN WILL ALSO SPREAD INTO THE SW...KRKS/KBPI/KPNA ROUTES AFTER 20Z. EAST OF THE DIVIDE...LOCAL LLWS WILL BE ENCOUNTERED BTWN KCOD-KLND ALONG THE EAST SLOPES OF THE ABSAROKA AND WIND RIVER RANGES ALONG WITH SOME TERRAIN OBSCURATIONS DUE TO BLSN. SW WIND AT 15-25KTS WILL ALSO RESULT IN BLSN AND LOCAL TERRAIN OBSCURATION BTWN KRKS-KCPR. && .FIRE WEATHER... WARMING TEMPERATURES EXPECTED OVER MUCH OF THE FORECAST AREA TODAY...WITH AREAS EAST OF THE DIVIDE SEEING TEMPERATURES IN THE MID TO UPPER 40S. SNOWFALL WILL DEVELOP OVER THE WESTERN MOUNTAINS AND VALLEYS TODAY...WHICH WILL CONTINUE INTO THE OVERNIGHT HOURS TONIGHT. A POTENTIALLY SIGNIFICANT STORM SYSTEM WILL MOVE INTO WESTERN WYOMING EARLY SUNDAY...AND WILL PUSH THROUGH THE STATE THROUGH MONDAY. THIS POTENTIALLY POTENT STORM SYSTEM MAY PRODUCE SIGNIFICANT SNOWFALL EAST OF THE DIVIDE ON MONDAY...AND MAY COUPLE WITH STRONG WINDS OVER NORTHERN JOHNSON COUNTY TO CREATE BLIZZARD CONDITIONS DURING THE LATE MORNING AND AFTERNOON HOURS OF MONDAY. COOLING TEMPERATURES EXPECTED SUNDAY AND MONDAY ACROSS THE STATE WITH THIS SYSTEM. PLEASE CHECK THE WINTER STORM PRODUCTS...WSWRIW...FOR FURTHER DETAILS ON THIS POTENTIALLY SIGNIFICANT WINTER STORM. && .RIW WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM SUNDAY EVENING THROUGH MONDAY AFTERNOON FOR WYZ004>006-008-009-011-020-022. BLIZZARD WATCH FROM SUNDAY EVENING THROUGH MONDAY AFTERNOON FOR WYZ010. && SHORT TERM...BRANHAM LONG TERM...SKRBAC AVIATION...AEM FIRE WEATHER...BRANHAM
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 500 AM MDT SAT MAR 28 2009 WYZ001>020-022>030-291100- ABSAROKA MOUNTAINS-BIGHORN MOUNTAINS SOUTHEAST- BIGHORN MOUNTAINS WEST-CASPER MOUNTAIN-CODY FOOTHILLS- EAST SWEETWATER COUNTY-FLAMING GORGE- GREEN MOUNTAINS AND RATTLESNAKE RANGE-JACKSON HOLE-LANDER FOOTHILLS- NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN- NORTHEAST JOHNSON COUNTY-OWL CREEK AND BRIDGER MOUNTAINS- ROCK SPRINGS AND GREEN RIVER-SALT RIVER AND WYOMING RANGES- SOUTH LINCOLN COUNTY-SOUTHEAST BIG HORN BASIN- SOUTHEAST JOHNSON COUNTY-SOUTHWEST BIG HORN BASIN-STAR VALLEY- TETON AND GROS VENTRE MOUNTAINS-UPPER GREEN RIVER BASIN- UPPER GREEN RIVER BASIN FOOTHILLS-UPPER WIND RIVER BASIN- WIND RIVER BASIN-WIND RIVER MOUNTAINS EAST-WIND RIVER MOUNTAINS WEST- YELLOWSTONE NATIONAL PARK- 500 AM MDT SAT MAR 28 2009 ...WINTER STORM AND BLIZZARD WATCHES IN EFFECT FOR NORTH CENTRAL AND EASTERN WYOMING SUNDAY EVENING THROUGH MONDAY AFTERNOON... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. .DAY ONE...TODAY AND TONIGHT SNOWFALL WILL MOVE INTO WESTERN WYOMING TODAY AND WILL INTENSIFY DURING THE LATE EVENING AND OVERNIGHT HOURS. THIS WILL CREATE SLICK AND SNOW PACKED ROADS OVER THE MOUNTAIN PASSES. STORM ACCUMULATIONS OF 6 TO 10 INCHES WILL BE POSSIBLE WHEN THE STORM WINDS DOWN ON SUNDAY EVENING. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY THE SYSTEM WHICH MAY BRING MODERATE SNOWFALLS OVER WESTERN WYOMING WILL MOVE EAST OF THE DIVIDE ON SUNDAY EVENING. AS THIS SYSTEM MOVES THROUGH THE AREA...SNOWFALL MAY BECOME HEAVY AT TIMES OVER THE IMPACTED AREAS. STRONG NORTHERLY WINDS ARE ANTICIPATED OVER NORTHERN JOHNSON COUNTY ON MONDAY WHICH WILL COMBINE WITH SNOWFALL TO CREATE CONSIDERABLY LOWERED VISIBILITIES WITH BLOWING AND DRIFTING SNOW. TOTAL SNOW ACCUMULATIONS OVER THE LOWER ELEVATIONS WILL RANGE FROM 4 TO 7 INCHES...WITH 10 TO 15 INCHES POSSIBLE OVER THE MOUNTAINS BY MONDAY EVENING. TRAVELING IN THIS SYSTEM MAY BECOME TREACHEROUS... STAY TUNED TO THE NATIONAL WEATHER SERVICE FOR FURTHER UPDATES REGARDING THIS POTENTIALLY POTENT WINTER STORM SYSTEM. ANOTHER STORM SYSTEM IS POSSIBLE LATER TUESDAY INTO WEDNESDAY ACROSS MUCH OF THE AREA. AND YET ANOTHER STORM SYSTEM MAY DEVELOP AND MOVE INTO WESTERN WYOMING DURING THE DAY FRIDAY AND THEN MOVE EAST OF THE DIVIDE FRIDAY NIGHT. STAY TUNED FOR THE LATEST FORECASTS FROM THE NATIONAL WEATHER SERVICE IN RIVERTON DURING THIS VERY ACTIVE AND QUICKLY CHANGING WEATHER PATTERN. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. TEAM RIVERTON
The national radar mosaic for the moment the first event began.
3 winter storm. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2009Every state in 2009This day in weather historyWarnings in Wyoming, March 2009
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 157799, 157800, 157798.