A favorable jet stream pattern and a tightening pressure gradient combined to create gusty west-northwest wind across portions of central Wyoming.
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The episode as NWS RIW wrote it up.
A favorable jet stream pattern and a tightening pressure gradient combined to create gusty west-northwest wind across portions of central Wyoming.
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 Dec 30, 2:43 AM MST, 7 hours 17 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 243 AM MST SUN DEC 30 2007 .SHORT TERM...TODAY THROUGH TUESDAY NIGHT AFTER A LULL LAST EVENING...HEAVY SNOW IS RETURNING TO THE WESTERN MOUNTAINS THIS MORNING. HEAVY SNOW ACROSS THE WESTERN MOUNTAINS AND VALLEYS WILL CONTINUE THROUGH THE AFTERNOON TODAY. COUPLED WITH STRONG WINDS OVER THESE AREAS...SIGNIFICANT BLOWING AND DRIFTING SNOW IS ANTICIPATED. WINTER STORM WARNING FOR THESE AREAS REMAINS IN EFFECT UNTIL 5 PM THIS EVENING WHEN SNOW AND WIND SHOULD BEGIN TO WEAKEN. TO THE EAST... HIGH WIND CONCERNS REMAIN ACROSS CENTRAL AND SOUTHERN WYOMING. AN IMPRESSIVE GRADIENT FLOW IS EXPECTED TO DEVELOP ACROSS THE CWA THIS MORNING RESULTING IN STRONG WINDS FOR PORTIONS OF CENTRAL AND SOUTHERN WYOMING. FORECAST CONTINUES THE THOUGHT THAT STRONG WINDS OF 35 TO 45 MPH WITH GUSTS OF 60 TO 65 MPH ARE EXPECTED OVER THE CODY FOOTHILLS...THE AREA OF DUBOIS...AND THE GREEN MOUNTAINS AND RATTLESNAKE RANGE. A HIGH WIND WARNING IS IN EFFECT FOR THESE AREAS TODAY. AS STRONG WINDS MOVE SOUTH OUT OF DUBOIS THIS AFTERNOON...WINDS WILL MOVE INTO THE REMAINDER OF WIND RIVER BASIN. HAVE STARTED A HIGH WIND WARNING STARTING AT 11 AM FOR THE CENTRAL WIND RIVER BASIN. THIS TYPE OF FLOW IS USUALLY NOT FAVORABLE FOR DEVELOPMENT OF HIGH WINDS OVER THE LANDER FOOTHILLS...SO HAVE LEFT THIS AREA OUT OF THE WARNING FOR NOW. CONTINUED THEIR HIGH WIND WATCH IN CASE SOMETHING DEVELOPS OVER THE AREA THIS AFTERNOON. A PRESSURE GRADIENT OVER THE WIND CORRIDOR BETWEEN ROCK SPRINGS AND GILLETTE OF AROUND 12 TO 13 MB CONTINUES TO BE INDICATED IN RECENT MODEL ANALYSIS. NAM GUIDANCE ALSO SUPPORTS HIGH WINDS OVER THE ROCK SPRINGS AREA THIS MORNING AND AFTERNOON. ISSUED A HIGH WIND WARNING WHICH INCLUDES THE I80 CORRIDOR THROUGH SWEETWATER COUNTY DUE TO THE EXPECTATION FOR WINDS OF 35 TO 45 MPH WITH GUSTS TO 60 MPH. WINDS OVER THE WIND RIVER BASIN AND CODY FOOTHILLS WILL TAPER OFF THIS EVENING...WITH WINDS ANTICIPATED TO WEAKEN OVER THE REMAINING AREAS AFTER MIDNIGHT. PASSAGE OF THIS STORM DURING THE OVERNIGHT HOURS WILL STILL LEAVE LINGERING LIGHT SNOW ACROSS MUCH OF THE CWA FOR MONDAY...THOUGH WILL STEADILY WEAKEN THROUGH MONDAY NIGHT AS A RIDGE BEGINS TO MOVE OVER THE AREA. THIS RIDGE IS EXPECTED TO BE FULLY IN PLACE ON TUESDAY BRINGING DRY AND CLEARING CONDITIONS ACROSS CENTRAL AND WESTERN WYOMING. PATCHY FOG POSSIBLE TUESDAY NIGHT AS A RESULT OF THE CLEARING. .LONG TERM...WEDNESDAY THROUGH SUNDAY TRANSITORY RIDGE MOVES OVERHEAD WEDNESDAY WITH STRONG VALLEY/BASIN INVERSIONS AND SOME PATCHY MORNING FOG POSSIBLE. ACTIVE PATTERN THEN RETURNS AS EARLY AS THURSDAY NIGHT IN THE WEST AND CONTINUES THROUGH THE WEEKEND UNABATED. THE STRONG ERN PACIFIC/WST COAST TROUGH THAT IS FORECAST TO DEVELOP WILL ALLOW SEVERAL STRONG SHORTWAVES TO ROTATE ACROSS THE BOTTOM OF THIS TROUGH IMPACTING THE WEST WITH PERIODS OF MODERATE TO HEAVY SNOWFALL. A STRONG PRESSURE GRADIENT WILL ALSO RESULT IN A VERY WINDY PERIOD ACROSS THE WIND CORRIDOR... CODY FOOTHILLS AND MOUNTAINS AT TIMES. THE SHORTWAVE THAT IS FORECAST TO MOVE ACROSS ON SATURDAY MAY BE POTENT ENOUGH FOR SOME SNOW EAST OF THE DIVIDE BUT WILL SEE IF THIS TREND CONTINUES BEFORE JUMPING ON THIS. I WILL...HOWEVER...EXPAND MY POPS ACROSS THE RED DESERT TO CHANCE CATEGORY FRIDAY THROUGH SUNDAY WITH SLIGHT CHANCES INTO ZONE 19 FOR STARTERS. THE SATURDAY SHORTWAVE SHOULD ALSO GIVE THE BASINS AND VALLEYS A CHANCE TO BREAK THEIR INVERSIONS. THIS TROUGH IS THEN FORECAST TO MOVE INTO THE GREAT BASIN AND CENTRAL ROCKIES ON MONDAY. MORE ON THAT TOMORROW. && .AVIATION... A POWERFUL PACIFIC STORM SYSTEM WILL BRING A STRONG...MOIST WEST FLOW INTO WESTERN WYOMING TODAY...WITH PERIODS OF HEAVY SNOW WEST OF THE DIVIDE. THE HEAVIEST SNOW IS EXPECTED THROUGH 18Z...WITH THE SNOW BECOMING LIGHT BETWEEN 18Z AND 00Z. IFR AND MVFR WILL BE COMMON ACROSS THE WESTERN TAF SITES...MAINLY KJAC...KBPI AND KPNA THROUGH 18Z...WITH SITES GRADUALLY BECOMING VFR IN THE EVENING. LIFR IS EXPECTED TO OCCUR DUE TO HEAVY SNOW AND BLOWING SNOW AT KJAC AND KPNA. VERY WINDY CONDITIONS ARE EXPECTED TODAY...ESPECIALLY IN THE AFTERNOON AFTER FRONTAL PASSAGE ACROSS MOST TAF SITES. SUSTAINED WESTERLY WINDS BETWEEN 20 AND 30 MPH WILL BE COMMON EAST OF THE DIVIDE IN THE AFTERNOON...WITH A FEW AREAS SUSTAINED BETWEEN 30 AND 40 WITH GUSTS NEAR 60 MPH. THE ONLY EXCEPTION WILL BE KWRL WHERE WINDS SHOULD NOT BE AS STRONG...AS OTHER TAF SITES THIS AFTERNOON. ALTHOUGH KWRL WILL STILL BE WINDY FROM THE NORTHWEST. && .FIRE WEATHER... HEAVY SNOW AND STRONG WINDS WILL REMAIN ACROSS WESTERN WYOMING TODAY...AND WILL CAUSE SIGNIFICANT BLOWING SNOW AND DRIFTING. ADDITIONALLY...THIS STORM WILL BRING STRONG WINDS ACROSS MUCH OF CENTRAL AND SOUTHERN WYOMING TODAY WITH WIND SPEEDS OF 35 TO 45 MPH AND GUSTS TO 65 MPH POSSIBLE. TEMPERATURES WILL WARM SLIGHTLY TODAY...THOUGH ARE EXPECTED TO DROP AGAIN ON MONDAY AS COLD AIR MOVES INTO THE AREA. MONDAY WILL SEE WEAKENING SNOW ACROSS CENTRAL AND WESTERN WYOMING WITH MOST AREAS BECOMING DRY BY MONDAY NIGHT. THESE DRY CONDITIONS WILL PREVAIL THROUGH TUESDAY. && .RIW WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 11 PM MST THIS EVENING FOR WYZ028-030. HIGH WIND WARNING UNTIL 11 PM MST THIS EVENING FOR WYZ019. HIGH WIND WATCH FROM 11 AM MST THIS MORNING THROUGH THIS AFTERNOON FOR WYZ018. WINTER STORM WARNING UNTIL 5 PM MST THIS AFTERNOON FOR WYZ001- 002-012>015-023>025-027. HIGH WIND WARNING FROM 11 AM THIS MORNING TO 5 PM MST THIS AFTERNOON FOR WYZ017. HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR WYZ003-016. && SHORT TERM...BRANHAM LONG TERM...SKRBAC AVIATION...WM FIRE WEATHER...BRANHAM
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RIVERTON WY 330 AM MST SUN DEC 30 2007 WYZ001>020-022>030-311200- 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- 330 AM MST SUN DEC 30 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING. ..WINTER STORM WARNINGS FOR WESTERN MOUNTAINS AND VALLEYS THROUGH THIS AFTERNOON... ...HIGH WIND WARNINGS FOR PORTIONS OF CENTRAL WYOMING FROM 11 AM THROUGH 5 PM AND SOUTHERN WYOMING THROUGH 11 PM THIS EVENING... ...HIGH WIND WATCH FOR THE LANDER FOOTHILLS FROM 11 AM THROUGH 5 PM TODAY... .DAY ONE...TODAY AND TONIGHT THE SECOND PART OF THE MAJOR WINTER STORM WILL IMPACT THE WEST TODAY. AS THE SNOW AND WIND INCREASE ONCE AGAIN...TRAVEL WILL BECOME INCREASINGLY HAZARDOUS DUE TO BLOWING AND DRIFTING SNOW...LIMITED VISIBILITIES...AND SLICK ROADS. USE CAUTION IF TRAVELLING THROUGH SUNDAY...ESPECIALLY OVER MOUNTAIN PASSES. SNOW WILL DECREASE TONIGHT BUT LIGHT SNOW WILL CONTINUE. NEW SNOWFALL OF 5 TO 10 INCHES IS EXPECTED IN MOST OF THE MOUNTAINS WITH ANOTHER 3 TO 6 INCHES IN THE VALLEYS. ELSEWHERE...VERY STRONG WEST WINDS ARE EXPECTED IN MANY AREAS FROM THE CODY FOOTHILLS SOUTH TROUGH DUBOIS...THE WIND RIVER BASIN... SWEETWATER STATION AND JEFFREY CITY SOUTH TO INCLUDE MUCH OF SWEETWATER COUNTY. WEST WINDS OF 30 TO 40 MPH WILL BE COMMON WITH GUSTS TO 60 MPH. WINDS WILL DECREASE LATER THIS EVENING. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY ANOTHER STORM SYSTEM MAY BRING SIGNIFICANT SNOWFALL TO FAR WESTERN WYOMING THURSDAY NIGHT THROUGH AT LEAST SATURDAY. STRONG SOUTHWEST WINDS MAY DEVELOP ACROSS THE AREA FROM EASTERN SWEETWATER COUNTY TO THE CASPER AREA AND IN THE CODY FOOTHILLS. STAY TUNED AS THE ACTIVE EARLY WINTER PATTERN CONTINUES. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT SNOWFALL AMOUNTS THROUGH TONIGHT ALONG WITH ANY MEASURED WIND SPEEDS. TEAM RIVERTON
The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2007Every state in 2007This day in weather historyWarnings in Wyoming, December 2007
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: 65635.