Wyoming, 2009High Wind in Wyoming, December 12, 2009
December 12, 2009 · NWS CYS · 2 events in 2 counties and zones
A large surface pressure gradient over the Rocky Mountains produced a short-lived, but strong wind event over portions of southeast Wyoming in the afternoon of December 12. The winds near the Interstate 25 Bordeaux exit knocked over a semi-truck around 1300 LST.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 2
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.
A large surface pressure gradient over the Rocky Mountains produced a short-lived, but strong wind event over portions of southeast Wyoming in the afternoon of December 12. The winds near the Interstate 25 Bordeaux exit knocked over a semi-truck around 1300 LST.
What forecasters said that day
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 12, 4:30 AM MST, 7 hours 20 minutes earlier.
Area forecast discussion, Dec 12, 4:30 AM MST, 7 hours 20 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
430 AM MDT MST SAT DEC 12 2009
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT...
HIGH LEVEL MOISTURE HAS INCREASED OVER THE AREA AS A GENERAL ZONAL
FLOW IN PLACE ACROSS MUCH OF THE COUNTRY WITH SOME LEE ENHANCED
CLOUDS ACROSS THE EASTERN CWA. TWO SYSTEMS EXPECTED TO AFFECT THE
CWA OVER THE NEXT 48 HOURS. ONE BEING AN UPPER LOW WHICH WILL MOVE
ONSHORE ALONG THE CAL COAST THIS EVENING THEN OPEN AND ACCELERATE
EASTWARD ACROSS THE REGION SUNDAY. THE OTHER BEING AN ARCTIC COLD
FRONT WHICH WILL SLIP SOUTHWESTWARD TONIGHT AND SHOULD LIE SOMEWHERE
FROM EAST CENTRAL WY INTO THE SOUTHERN NEB PANHANDLE SUNDAY.
OBVIOUSLY POSITION OF THIS FRONT WILL BE CRITICAL FOR TEMPERATURES.
SOME LIGHT SNOWS ALSO EXPECTED TONIGHT THROUGH SUNDAY...MAINLY OVER
THE MTNS WITH THE UPPER SYSTEM AND OVER THE NORTHERN CWA IN
ASSOCIATION WITH THE FRONT. SNOWFALL AMOUNTS NOT EXPECTED TO BE
HIGH BUT AT LEAST A FEW INCHES OVER THE HIGHER MTNS. OTHERWISE
LOCALLY WINDY CONDITIONS WILL PERSIST OVER WIND PRONE AREAS TODAY
AND SUNDAY. ARCTIC FRONT SHOULD BEGIN TO PULL BACK EAST SUNDAY NIGHT
BUT STILL QUITE COLD OVER THE NORTHEAST PART OF THE NEBRASKA
PANHANDLE.
.LONG TERM...MONDAY THROUGH FRIDAY. DECEMBER 11TH 5PM MST ECMWF AND
GFS 500 MB SYNOPTIC PATTERNS SIMILAR...LEADING TO HIGH CONFIDENCE IN
THEIR RESPECTIVE MODEL SOLUTIONS.
MONDAY...STARK CONTRAST IN MAXIMUM TEMPERATURES FROM CHEYENNE TO
CHADRON AS SHALLOW ARCTIC AIRMASS WILL RESIDE ACROSS OUR EASTERN
COUNTIES. HIGH TEMPERATURES IN THE 30S TO LOWER 40S WEST OF THE
BOUNDARY...WITH TEENS AND 20S IN THE ARCTIC AIRMASS EAST OF THE COLD
FRONT. ISOLATED SNOW SHOWERS IN THE UPSLOPE REGIME IN THE ARCTIC
AIRMASS WITH SCATTERED TO NUMEROUS OROGRAPHIC SNOW SHOWERS ACROSS
THE SNOWY RANGE IN MOIST WEST FLOW ALOFT.
TUESDAY...TEMPERATURES NEAR CLIMATOLOGICAL NORMALS WITH HIGHS IN THE
20S AND 30S WITH 1000-500 MB THICKNESSES NEAR 5430 METERS AND
SIGNIFICANT AMOUNTS OF OPAQUE MIDDLE AND HIGH LEVEL CLOUDINESS
DOWNWIND OF A DIRTY RIDGE ALOFT ACROSS THE GREAT BASIN STATES.
OROGRAPHIC SNOW SHOWERS WILL REMAIN WEST OF THE SNOWY RANGE...AND
ACROSS FAR WESTERN WYOMING.
WEDNESDAY...WARMING TREND ON TAP AS 1000-500 MB THICKNESSES WARM TO
5520 METERS. HIGH TEMPERATURES IN THE 30S TO MIDDLE 40S...ASSUMING
MIDDLE AND HIGH CLOUD OPACITY IS MINIMAL.
THURSDAY...HIGH TEMPERATURES EVEN WARMER WITH 30S WEST TO 40S EAST
WITH 1000-500 MB THICKNESSES NEAR 5520 METERS...AND ASSUMING MINIMAL
AND NEGLIGIBLE OPACITY EFFECT FROM MIDDLE AND HIGH CLOUDS.
FRIDAY...MILD WEATHER TREND CONTINUES FROM THURSDAY WITH NORTHWEST
FLOW ALOFT...500 MB HEIGHTS NEAR 5730 METERS...1000-500 MB
THICKNESSES NEAR 5570 METERS AND MINIMAL OPACITY FROM MIDDLE AND
HIGH CLOUDS. HIGH TEMPERATURES FROM MID 30S ACROSS CARBON COUNTY
WYOMING TO UPPER 40S ACROSS FAR SOUTHEAST WYOMING AND MUCH OF
SOUTHWEST NEBRASKA.
&&
.AVIATION...VFR TODAY...EXCEPT FOR MVFR IN SCATTERED SNOW SHOWERS
ACROSS SOUTHWEST CARBON COUNTY AND THE SNOWY RANGE. SNOWY RANGE
MOUNTAINS OCCASIONALLY OBSCURED.
VFR TONIGHT...EXCEPT FOR IFR AND MVFR IN SNOW SHOWERS ACROSS CARBON
COUNTY AND IN LOW CLOUDS AND FOG EAST OF AN ARCTIC COLD FRONT FROM
DOUGLAS TO KIMBALL. MOUNTAINS OBSCURED.
VFR SUNDAY...EXCEPT FOR IFR AND MVFR IN SNOW SHOWERS...FOG AND LOW
CLOUDS NORTH OF A LARAMIE TO ALLIANCE LINE. MOUNTAINS OBSCURED.
&&
.FIRE WEATHER...NO CONCERNS ANTICIPATED THROUGH SUNDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
SHORT TERM/FIRE WEATHER...RE
LONG TERM/AVIATION...RUBIN
Hazardous weather outlook, Dec 12, 4:28 AM MST, 7 hours 22 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHEYENNE WY
428 AM MST SAT DEC 12 2009
NEZ002-003-019>021-054-055-095-096-WYZ101>105-107>109-111-113-115-
117>119-131200-
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-EAST PLATTE COUNTY-
GOSHEN COUNTY-CENTRAL CARBON COUNTY-SOUTHWEST CARBON COUNTY-
UPPER NORTH PLATTE RIVER BASIN-LARAMIE VALLEY-
SOUTH LARAMIE RANGE FOOTHILLS-CENTRAL LARAMIE COUNTY-
EAST LARAMIE COUNTY-
428 AM MST SAT DEC 12 2009
THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA
PANHANDLE...EAST CENTRAL WYOMING...SOUTH CENTRAL WYOMING AND
SOUTHEAST WYOMING.
.DAY ONE...TODAY AND TONIGHT
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY
THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.
.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
WYZ106-110-116-131200-
CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY-
NORTH SNOWY RANGE FOOTHILLS-SOUTH LARAMIE RANGE-
428 AM MST SAT DEC 12 2009
THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL WYOMING...
SOUTH CENTRAL WYOMING AND SOUTHEAST WYOMING.
.DAY ONE...TODAY AND TONIGHT
LOCALLY GUSTY WINDS CAN BE EXPECTED THROUGH TONIGHT. SOME GUSTS IN
EXCESS OF 45 MPH ARE LIKELY ESPECIALLY IN WIND PRONE AREAS.
.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY
THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.
.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
WYZ112-114-131200-
SIERRA MADRE RANGE-SNOWY RANGE-
428 AM MST SAT DEC 12 2009
THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL WYOMING.
.DAY ONE...TODAY AND TONIGHT
SNOW SHOWERS ARE EXPECTED TO INCREASE OVER THE MOUNTAINS TONIGHT
WITH SOME LIGHT ACCUMULATIONS POSSIBLE ALONG WITH AREAS OF BLOWING
SNOW.
.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY
SCATTERED TO NUMEROUS SNOW SHOWERS WILL CONTINUE SUNDAY INTO SUNDAY
NIGHT WITH SEVERAL INCHES OF NEW SNOW LIKELY.
.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
In the hours before
Special weather statement, Dec 12, 11:07 AM MST, 43 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
1107 AM MST SAT DEC 12 2009
WYZ106-110-122100-
CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY-
NORTH SNOWY RANGE FOOTHILLS-
INCLUDING THE CITIES OF...BORDEAUX...ARLINGTON...ELK MOUNTAIN
1107 AM MST SAT DEC 12 2009
...GUSTY SOUTHWEST WINDS TO CONTINUE THROUGH THIS AFTERNOON...
STRONG AND GUSTY SOUTHWEST WINDS WILL CONTINUE ACROSS PORTIONS OF
SOUTHEAST WYOMING THROUGH THE AFTERNOON. 30 TO 40 MPH WITH LOCALLY
HIGHER WINDS SPEEDS AND GUSTS TO 55 MPH CAN BE EXPECTED ALONG
INTERSTATE 80 NEAR ARLINGTON AND ALONG INTERSTATE 25 NEAR
BORDEAUX.
MOTORISTS ARE URGED TO EXERCISE CAUTION WHILE DRIVING IN THESE
AREAS AND BE PREPARED FOR THESE LOCALLY STRONG WINDS.
RJM
High Wind, Central Laramie Range and Southwest Platte County
- When
- December 12, 11:50 AM MST to 2:15 PM MST
- Where
- Central Laramie Range and Southwest Platte County forecast zone
- Measured
- 65 kt (75 mph) measured gust
- Reported by
- Department of Highways
- Coordinates
- 41.698, -105.127 (the zone’s center; the record gives no point)
Wyoming Department of Transportation sensor near the Bordeaux exit of Interstate 25 measured a peak gust of 75 MPH between 1300 and 1315 LST with sustained winds in excess of 40 MPH from 1150 to 1415 LST.
High Wind, South Laramie Range Foothills
- When
- December 12, 1:00 PM MST to 2:05 PM MST
- Where
- South Laramie Range Foothills forecast zone
- Measured
- 39 kt (45 mph) measured sustained
- Reported by
- Department of Highways
- Coordinates
- 41.481, -105.207 (the zone’s center; the record gives no point)
Wyoming Department of Transportation sensor near Whitaker measured a peak gust of 56 MPH at 1310 LST with sustained winds in excess of 40 MPH from 1300 to 1405 LST.
- High Wind
- Sustained non-thunderstorm winds of 40 mph or more for an hour, or gusts of 58 mph or more.
After NWS Directive 10-1605, the rules offices file Storm Data by.
- Flash Flooding in Louisiana, December 12, 20091 death · 6 events
- Flash Flood and High Wind in California, December 12 to 13, 2009$102,000 · 87 kt wind · 3 events
- Winter Weather in North Carolina, December 12 to 13, 200920 events
- Extreme Cold in North Dakota, December 12 to 15, 200917 events
- Winter Storm in Utah, December 12 to 14, 200913 events
- Winter Storm in Wyoming, December 12 to 13, 20097 events
- Heavy Snow in Idaho, December 12 to 13, 20095 events
- Winter Storm and Winter Weather in Utah, December 12 to 13, 20094 events
- Winter Storm in Montana, December 12 to 13, 20094 events
- Flash Flooding and Damaging Wind in California, December 12 to 13, 200955 kt wind · 4 events
- Flash Flooding in Alabama, December 12, 20093 events
- Extreme Cold in Montana, December 12 to 13, 20093 events
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: 201083, 201084.