Strong and gusty winds returned to portions of southeast Wyoming during the early morning hours of December 16. These winds were likely a continuation of the December 15th event.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS CYS wrote it up.
Strong and gusty winds returned to portions of southeast Wyoming during the early morning hours of December 16. These winds were likely a continuation of the December 15th event.
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 Cheyenne, WY wrote its last area forecast discussion before the first event at Dec 15, 9:43 PM MST, 4 hours 24 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CHEYENNE WY 943 PM MST TUE DEC 15 2009 .UPDATE... BASED ON OBSERVATIONS OVER THE PAST SEVERAL HOURS...HAVE DECIDED TO GO AHEAD AND END THE HIGH WIND WARNING A BIT EARLIER THAN ANTICIPATED. BREEZY WINDS OF 20 TO 30 MPH WITH GUSTS TO AROUND 50 MPH WILL STILL BE POSSIBLE TONIGHT AND ESPECIALLY AGAIN TOMORROW AFTERNOON AHEAD OF THE APPROACHING COLD FRONT. TEMPERATURES TONIGHT WILL CONTINUE TO BE A CHALLENGE...ESPECIALLY IN THE NEBRASKA PANHANDLE...WITH THE LEE TROUGH EXPECTED TO SHIFT EAST AS A WARM FRONT. THE COLD AIR REMAINS IN THE NORTH PLATTE RIVER VALLEY LATE THIS EVENING...BUT MAY SCOUR OUT OVERNIGHT WITH WARMING TEMPERATURES INTO THE 20S. THIS HAS ALREADY OCCURRED TONIGHT IN THE CHADRON AREA WHERE THE COLDER AIRMASS WAS IN PLACE MUCH OF TODAY. TEMPERATURES TOMORROW IN SOUTHEAST WYOMING WILL PEAK OUT AT AROUND 10 DEGREES ABOVE NORMAL VALUES AS COMPRESSIONAL WARMING USUALLY HELPS BUMP UP TEMPERATURES EVEN A BIT ABOVE GUIDANCE VALUES IN A PRE-FRONTAL ENVIRONMENT. && .LONG TERM...THURSDAY NIGHT THROUGH NEXT TUESDAY... MODELS IN REASONABLE AGREEMENT INTO THE WEEKEND...BUT THEN SOLUTIONS DIVERGE SIGNIFICANTLY LATE IN THE WEEKEND AND EARLY NEXT WEEK. MODELS GENERALLY SHOW NORTH TO NORTHWEST FLOW FRIDAY AND SATURDAY AS A SERIES OF WEAK PACIFIC TROUGHS QUICKLY PUSH ACROSS THE NRN AND CNTRL ROCKIES AND INTO THE PLAINS. EXPECT TEMPERATURES TO BE NEAR OR SLIGHTLY BELOW NORMAL FOR THIS TIME OF THE YEAR GOING INTO THE WEEKEND WITH A CHC OF SNOW ACROSS THE AREA THURSDAY NIGHT AND EARLY FRIDAY MORNING. SNOW ACCUMULATIONS APPEAR TO BE MINIMAL AT THIS TIME WITH MANY AREAS OVER THE LOWER ELEVATION RECEIVING ONLY SNOW FLURRIES AS A WEAK COLD FRONT MOVES ACROSS THE AREA THURSDAY EVENING. BY SUNDAY...MODELS SHOW ANOTHER COLD FRONT PUSHING SOUTHWARD OUT OF CANADA AS AN ARCTIC AIRMASS MOVES INTO SRN CANADA AND THE NRN PLAINS. GFS IS THE FURTHEST WEST WITH THE ARCTIC AIRMASS...SHOWING A DEEPER TROUGH DIGGING SOUTHEAST OVER THE NRN ROCKIES WITH ANOTHER CHC OF SNOW AND MUCH COLDER TEMPS ACROSS THE REGION. IN CONTRAST...OTHER MODELS INCLUDING THE GEM AND ECMWF ARE SHOWING THIS AIRMASS FURTHER TO THE EAST WITH ONLY A WEAK SHORTWAVE QUICKLY PUSHING ACROSS THE HIGH PLAINS. WITH THE GFS THE OUTLIER...TRENDED TOWARDS THE GEM AND ECMWF WITH LOWER POP AND TEMPS NEAR NORMAL IN WYOMING...WITH BELOW NORMAL TEMPS OVER THE NEBRASKA PANHANDLE CLOSER TO THE ARCTIC AIRMASS. BY EARLY NEXT WEEK...GFS SHOWS MAINLY WESTERLY FLOW AS ANOTHER UPPER LEVEL TROUGH ESTABLISHES ITSELF OVER THE PACIFIC NORTHWEST...SLOWLY DRIFTING EASTWARD INTO TUESDAY. THE ECMWF SHOWS THIS TROUGH MOVING EASTWARD MUCH SOONER COMPARED TO THE GFS...MOVING INTO THE AREA BY LATE TUESDAY BRINGING COLDER TEMPS AND SNOW. LOW CONFIDENCE WITH DAYS 6 AND 7...THEREFORE DID NOT MAKE MANY CHANGES TO THE PREVIOUS FORECAST AND TRENDED POP TOWARDS CLIMO WITH A CHC OF SNOW OVER THE MOUNTAINS ALONG AND WEST OF THE LARAMIE RANGE. KEPT POP BELOW 15 PCT OVER THE HIGH PLAINS OF ERN WYOMING AND THE NEBRASKA PANHANDLE WITH TEMPS SLIGHTLY BELOW NORMAL. && .AVIATION... BREEZY SOUTH TO SOUTHWEST WINDS WILL CONTINUE THROUGH THIS EVENING...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE NEAR KLAR AND KRWL...AND THE BREEZY WINDS WILL CONTINUE AHEAD OF A COLD FRONTAL PASSAGE WEDNESDAY EVENING. OTHERWISE...VFR CONDITIONS ARE STILL EXPECTED INTO WEDNESDAY WITH INTERVALS OF MID TO HIGH CLOUDS PUSHING ACROSS THE REGION. && .FIRE WEATHER... BREEZY WINDS WILL BE PRESENT ACROSS THE DISTRICT TONIGHT AND WEDNESDAY WITH A COLD FRONT EXPECTED TO PASS FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA EARLY WEDNESDAY EVENING. THIS WILL PRODUCE COOLER TEMPERATURES THURSDAY...THOUGH STILL A FEW DEGREES ABOVE NORMAL. HIGHS WEDNESDAY IN SOUTHEAST WYOMING ARE EXPECTED TO BE AROUND TEN DEGREES ABOVE NORMALS FOR MID-DECEMBER...BUT CLOSER TO NORMAL CONDITIONS CAN BE EXPECTED IN THE NEBRASKA PANHANDLE WHICH WILL BE CLOSER TO THE COLDER AIRMASS. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && SHORT TERM/FIRE WEATHER...CARPENTER LONG TERM...TJT AVIATION...CYS
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE CHEYENNE WY 1128 PM MST TUE DEC 15 2009 NEZ002-003-019>021-054-055-095-096-WYZ101>119-170630- DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE- NORTH SIOUX-SOUTH SIOUX-CONVERSE COUNTY LOWER ELEVATIONS- NIOBRARA COUNTY-NORTH LARAMIE RANGE- FERRIS/SEMINOE/SHIRLEY MOUNTAINS-SHIRLEY BASIN- CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY- EAST PLATTE COUNTY-GOSHEN COUNTY-CENTRAL CARBON COUNTY- NORTH SNOWY RANGE FOOTHILLS-SOUTHWEST CARBON COUNTY- SIERRA MADRE RANGE-UPPER NORTH PLATTE RIVER BASIN-SNOWY RANGE- LARAMIE VALLEY-SOUTH LARAMIE RANGE-SOUTH LARAMIE RANGE FOOTHILLS- CENTRAL LARAMIE COUNTY-EAST LARAMIE COUNTY- 1128 PM MST TUE DEC 15 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA PANHANDLE...EAST CENTRAL WYOMING...SOUTH CENTRAL WYOMING AND SOUTHEAST WYOMING. .DAY ONE...TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THERE IS A CHANCE OF SNOW ACROSS THE AREA THURSDAY INTO FRIDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
1146 PM MST TUE DEC 15 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0901 AM NON-TSTM WND GST ARLINGTON 41.59N 106.21W
12/15/2009 M56 MPH CARBON WY DEPT OF HIGHWAYS
WYDOT SITE ALONG I-80. ELEV. 7763 FT.
1252 PM NON-TSTM WND GST ESTERBROOK 42.41N 105.36W
12/15/2009 M58 MPH CONVERSE WY MESONET
RAWS SITE. ELEV. 6597 FT.
0130 PM NON-TSTM WND GST BORDEAUX 41.95N 104.95W
12/15/2009 M60 MPH PLATTE WY DEPT OF HIGHWAYS
WYDOT SITE ALONG I-25. ELEV. 4698 FT.
0152 PM NON-TSTM WND GST ESTERBROOK 42.41N 105.36W
12/15/2009 M59 MPH CONVERSE WY MESONET
RAWS SITE. ELEV. 6597 FT.
0206 PM NON-TSTM WND GST DEER CREEK 42.83N 105.78W
12/15/2009 M57 MPH CONVERSE WY DEPT OF HIGHWAYS
WYDOT SITE ALONG I-25. ELEV. 5098 FT.
0341 PM NON-TSTM WND GST ARLINGTON 41.59N 106.21W
12/15/2009 M59 MPH CARBON WY DEPT OF HIGHWAYS
WYDOT SITE ALONG I-80. ELEV. 7763 FT.
&&
JLHThe national radar mosaic for the moment the first event began.
3 high wind. Local standard time, as filed.
The Union Pacific Railroad sensor at 3S Federal measured a wind gust of 65 MPH at 0207 MST.
Wyoming Department of Transportation sensor at Bordeaux (KBRX) measured a gust of 60 mph at 0330 MST, and again at 0515 MST.
Wyoming Department of Transportation sensor at Bordeaux (KBRX) measured sustained winds of 35 to 45 MPH from 1125 MST to 1520 MST, with gusts of 60 MPH at 1235-1240 MST and again at 1405-1410 MST.
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, December 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: 201974, 201973, 201975.