A potent Pacific storm system moved southeast across southern Wyoming and northern Colorado. It generated significant snowfall and strong winds over the Snowy and Sierra Madre mountain ranges.
Every event with a place to put it; 10 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.
A potent Pacific storm system moved southeast across southern Wyoming and northern Colorado. It generated significant snowfall and strong winds over the Snowy and Sierra Madre mountain ranges. The heaviest snow fell over the Sierra Madre Range, with estimates of 20 to 40 inches. Over the Snowy Range, snowfall estimates ranged from 10 to 20 inches. Sustained westerly winds of 30 to 45 mph with gusts to 75 mph created considerable blowing and drifting snow.
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 Nov 12, 4:56 AM MST, 1 hour 4 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
456 AM MST SAT NOV 12 2011
.AVIATION...12Z TAF ISSUANCE
EXPECT VFR CEILINGS EAST OF THE LARAMIE RANGE THROUGH TONIGHT.
ALONG AND WEST OF THE RANGE WILL EXPERIENCE MVFR TO LOCAL IFR
CEILINGS AND VISIBILITIES DEVELOPING BY THIS AFTERNOON IN AREAS
OF RAIN AND SNOW AS A STRONG COLD FRONT MOVES ACROSS WYOMING. THE
MOUNTAINS WILL BE OBSCURED AS WELL. WESTERLY SURFACE WINDS WILL
GUST AS HIGH AS 55 KT ALONG AND WEST OF THE LARAMIE RANGE TODAY
AND TONIGHT. WIND GUSTS WILL BE AS HIGH AS 35 KT OVER THE WESTERN
PANHANDLE AS WELL. AFTER A BRIEF DECREASE IN THE WINDS ON
SUNDAY...VERY STRONG WINDS WILL DEVELOP SUNDAY NIGHT AND PERSIST
THROUGH MONDAY NIGHT...ESPECIALLY ALONG AND WEST OF THE LARAMIE
RANGE.
&&
.PREV DISCUSSION... /ISSUED 321 AM MST SAT NOV 12 2011/
SHORT TERM...TODAY THROUGH MONDAY...
TODAY...PROGRESSIVE SHORTWAVE TROUGH MOVES TO CENTRAL WYOMING WITH
ITS ASSOCIATED STRONG COLD FRONT SWEEPING ACROSS MOST OF SOUTHEAST
WYOMING. INHERITED HIGH WIND WARNING LOOKS GOOD...THOUGH STRONGEST
WINDS WILL BE REDUCED AS MOST LOCATIONS WILL BE IN THE RISING MOTION
THIS AFTERNOON. WINTER STORM WARNING LOOKS ON TRACK BASED ON
QPF FOR THE SNOWY RANGE AND SIERRA MADRE RANGE.
TONIGHT...FAST MOVING SHORTWAVE TROUGH WILL BE IN WESTERN NEBRASKA
BY MIDNIGHT. WITH STRONG COLD AIR ADVECTION THIS EVENING...EXPECT 60
TO 70 MPH WINDS TO OCCUR AFTER STRONGER WINDS ALOFT ARE TRANSPORTED
DOWNWARD...ESPECIALLY JUST EAST OF THE MOUNTAINS.
SUNDAY...FAST WEST NORTHWEST FLOW ALOFT CONTINUES. WILL KEEP
SCATTERED TO NUMEROUS SNOW SHOWERS OVER THE MOUNTAINS...DRY
ELSEWHERE DUE TO DOWNSLOPING.
SUNDAY NIGHT...WINDY CONDITIONS CONTINUE AS DEEP SURFACE TO 700 MB
UNIDIRECTIONAL WINDS ARE PROGGED...ALONG WITH STRONG GRADIENTS.
MONDAY...NAM PROJECTS A LARGE AREA OF 50+ KNOT WINDS OVER THE
FOOTHILLS...THUS ANOTHER POSSIBLE HIGH WIND EVENT FOR LOCATIONS
ACROSS SOUTHEAST WYOMING. WILL HOLD OFF ON HILITES FOR NOW TO
AVOID CONFUSION FROM THE PREVIOUS HILITES. COLD AND BLUSTERY DAY
WITH STRONG WINDS AGAIN.
LONG TERM...MONDAY THROUGH FRIDAY...
SOMEWHAT BETTER AGREEMENT IS GLEANED FROM THE 00Z DETERMINISTIC
MODEL OUTPUT EARLY THIS MORNING COMPARED TO YESTERDAY AT THIS
TIME. THE MAIN FORECAST CHALLENGE WILL BE THE POTENTIAL FOR
STRONG WINDS EARLY IN THE LONG TERM...I.E. MONDAY TO TUESDAY
PERIOD. THE GEFS 700 MB WIND STANDARDIZED ANOMALY FORECAST VALID
AT 00Z 15 NOV SHOWED 3 TO 4 STANDARD DEVIATIONS OVER SOUTHEAST
WYOMING. THIS AREA IS IN THE RIGHT EXIT REGION OF A 120+ KT UPPER
LEVEL JET...FAVORING DOWNWARD VERTICAL MOTION. THIS IS ALSO SHOWN
IN THE 700-500 MB VERTICAL VELOCITY FIELDS. THE GFS PROGS 50-70 KT
700 MB WINDS OVER THE SAME AREA AS WELL. THEREFORE...HIGH WIND
HILITES WILL LIKELY BE EXTENDED FROM THE END OF THE SHORT TERM
PERIOD THROUGH TUESDAY. ANOTHER POTENT SHORTWAVE TROUGH IS FORECAST
TO PUSH EAST ACROSS MONTANA AND THE DAKOTAS ON TUESDAY...DRAGGING
A COLD FRONT SOUTHEAST THROUGH THE CWA. MOIST UPSLOPE FLOW WILL
FAVOR OROGRAPHIC SNOW OVER THE MOUNTAINS WEST OF THE LARAMIE RANGE
TUESDAY...WITH LITTLE OR NO PRECIPITATION IN THE DOWNSLOPE WIND
REGIME EAST OF THE LARAMIE RANGE. MONDAY/S HIGH TEMPERATURES WILL
BE ABOUT 5 DEGREES ABOVE NORMAL PRIOR TO THE COLD FRONTAL PASSAGE...
THEN COOL 5 TO 10 DEGREES ACROSS THE NORTHERN PORTION OF THE CWA
FOR TUESDAY. WESTERLY WINDS WILL NOT BE AS WINDY WEDNESDAY AS THE
500-850 MB HEIGHTS/PRESSURE GRADIENTS WEAKEN UNDER THE DEVELOPING
ZONAL FLOW PATTERN. SURFACE HIGH PRESSURE BUILDS OVER THE REGION
FOR WEDNESDAY AND THURSDAY...WITH A WARM FRONT MOVING INTO THE
HIGH PLAINS. THIS WILL ALLOW A MODERATING TREND IN TEMPERATURES TO
ABOVE NORMAL LEVELS ONCE AGAIN. ALSO...THIS ZONAL FLOW WILL DRY
OUT THE LOW/MID LEVELS OF THE ATMOSPHERE RESULTING IN NO
PRECIPITATION. THE 00Z ENSEMBLES CONTINUE TO DEPICT A DEEP AMPLITUDE
TROUGH DIGGING SOUTHEAST ACROSS THE PACIFIC NORTHWEST BY FRIDAY.
THIS WILL CAUSE THE FLOW ALOFT TO BACK TO THE SOUTHWEST...MAINTAINING
THE MILD TEMPERATURES FOR FRIDAY. SOME MOISTURE TRIES TO ADVECT
NORTHEAST INTO AREAS WEST OF THE LARAMIE RANGE...WITH CHANCES FOR
RAIN AND SNOW ON FRIDAY.
&&
FIRE WEATHER...
NO FIRE WEATHER CONCERNS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL MIDNIGHT MONDAY FOR WYZ112-WYZ114.
HIGH WIND WARNING UNTIL 6 AM SUNDAY FOR WYZ101-WYZ103-WYZ104-
WYZ105-WYZ106-WYZ107-WYZ109-WYZ110-WYZ113-WYZ115-WYZ116-
WYZ117-WYZ118.
NE...NONE.
&&
SHORT TERM/FIRE WEATHER...RUBIN
LONG TERM/AVIATION...JAMSKIHAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 523 AM MST SAT NOV 12 2011 WYZ101>119-131230- 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- 523 AM MST SAT NOV 12 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL WYOMING... SOUTH CENTRAL WYOMING AND SOUTHEAST WYOMING. .DAY ONE...TODAY AND TONIGHT STRONG AND GUSTY WESTERLY WINDS OF 60 TO 75 MPH WILL OCCUR ALONG THE INTERSTATE 80 AND 25 WIND CORRIDORS. A HIGH WIND WARNING IS IN EFFECT FOR MOST OF SOUTHEAST WYOMING THROUGH 6 AM SUNDAY. SNOW WILL DEVELOP THIS MORNING OVER THE MOUNTAINS OF CARBON COUNTY...AND CONTINUE THROUGH TONIGHT. A WINTER STORM WARNING IS IN EFFECT FOR MODERATE TO HEAVY SNOW ACCUMULATIONS AND BLOWING SNOW FOR THE SNOWY AND SIERRA MADRE RANGES THROUGH SUNDAY EVENING. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY WESTERLY WINDS WILL DECREASE SLIGHTLY ON SUNDAY...BUT INCREASE ONCE AGAIN SUNDAY NIGHT AND MONDAY...WITH GUSTS OF 60 TO 75 MPH POSSIBLE FOR THE WIND CORRIDORS IN SOUTHEAST WYOMING. MODERATE TO HEAVY SNOW WILL CONTINUE SUNDAY OVER THE SIERRA MADRE AND SNOWY RANGES SUNDAY BEFORE GRADUALLY TAPERING OFF SUNDAY NIGHT. WINDS WILL DIMINISH SOMEWHAT FOR TUESDAY AND WEDNESDAY OVER SOUTHEAST WYOMING. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT...HOWEVER REPORTS OF SNOWFALL AND STRONG WINDS WILL BE APPRECIATED. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE NEZ002-003-019>021-054-055-095-096-131230- DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE- NORTH SIOUX-SOUTH SIOUX- 523 AM MST SAT NOV 12 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA PANHANDLE. .DAY ONE...TODAY AND TONIGHT GUSTY WESTERLY WINDS OF 30 TO 40 MPH WILL DEVELOP LATER THIS MORNING AND CONTINUE TONIGHT AS A COLD FRONT MOVES THROUGH THE AREA. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY AFTER A BRIEF LULL SUNDAY...WINDS WILL INCREASE SUNDAY NIGHT AND MONDAY. GUSTS OF 35 TO 45 MPH WILL BE POSSIBLE ON MONDAY. .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 JAMSKI
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Service Notice</title>
<link rel="stylesheet" href="index.css">
</head>
<body>
<main class="wrap">
<section class="card" role="status" aria-live="polite">
<div class="status" id="status">Temporary Notice</div>
<h1 id="headline">This service is currently unavailable.</h1>
<p id="message1">
The site you requested is temporarily down for maintenance or an unexpected outage.
</p>
<p id="message2">
Please try again in a few minutes.
</p>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html>PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
347 AM MST SAT NOV 12 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0320 AM NON-TSTM WND GST BORDEAUX 41.95N 104.95W
11/12/2011 M59 MPH PLATTE WY DEPT OF HIGHWAYS
&&
MJAMSKIThe national radar mosaic for the moment the first event began.
10 heavy snow. Local standard time, as filed.
The Divide Peak SNOTEL site indicated 19.5 inches.
The Battle Mountain SNOTEL site indicated 22.5 inches.
The Sandstone Ranger Station SNOTEL site indicated 12 inches.
The Old Battle SNOTEL site indicated 40.5 inches.
The Webber Springs SNOTEL site indicated 39 inches.
The Whiskey park SNOTEL site indicated 31.5 inches.
The North French Creek SNOTEL site indicated 16.5 inches.
The Sand Lake SNOTEL site indicated 19.5 inches.
The Brooklyn Lake SNOTEL site indicated 15 inches.
The Cinnabar Park SNOTEL site indicated 13.5 inches.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2011Every state in 2011This day in weather historyWarnings in Wyoming, November 2011
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 2026-09-30. Each event’s entry at NCEI: 347349, 347350, 347351, 347352, 347353, 347354, 347355, 347356, 347357, 347358.