Weekend Will Bring Warmer,Drier Weather

Following is the link to the Weather Summary  through the weekend ahead, prepared by the Riverton Forecast Office.

Weekly Weather Video

Snow?

Memorial  Day will see the beginning of a change in the weather for Star Valley, leading to a rather unsettled week ahead. An unseasonably strong jet stream will be shifting eastward from the Pacific Ocean across the western states.  This will bring a turn to colder and wetter for much of the area from Idaho/Wyoming northward.

Here is a series of forecast charts for the 250 mb level(jet stream level) depicting this change.

Sunday evening 5/26/13

Monday evening 5/27/13

Tuesday evening 5/28/13

Wednesday evening 5/29/13

Thursday evening 5/30/13

The strong jet moves from the Pacific and by mid week has resulted in a large trough centered over Wyoming, bringing with it much cooler air and several periods of showers and thundershowers.  These will first show up mainly to the north and west of Wyoming on Monday  as the air mass gradually moistens and begins to cool.   Tuesday and Wednesday will see more widespread showers as the upper trough develops and the jet stream crosses the Western states to the south of Wyoming.

Here are a series of surface charts and model forecast precipitation.

Monday evening 5/27/13

Tuesday evening 5/28/13

Wednesday evening 5/29/13

Thursday evening 5/30/13

It is quite apparent that precipitation will affect a wide area surrounding Wyoming this coming week.  The total precipitation forecast by the NWS for the next 5 days includes significant amounts as far south as western Wyoming, with a very wet week in store from Montana eastward into the Plains.

Total precipitation expected from Sunday to Friday of this week.

There is no doubt it will be cold enough for snow in the higher elevations of western Wyoming by mid week, with possible significant totals above 8-9000 feet. A mixture of rain and snow is possible as low as the floor of Star Valley by mid-week during the overnight and morning hours.  However any real accumulations are not expected at this time.

Travel into higher elevations such as Yellowstone NP, Wind Rivers and across the recently opened Bear Tooth Pass could definitely be impacted later this week.

Memorial Weekend Looking Good

Here is the weekly weather briefing prepared and provided by the Riverton Forecast Office.

Memorial Weekend Weather Briefing

Moore Tornado discussed by Dr. Jim Steenburg U of U and Dr. Jeff Masters U of W

There are two excellent blogs on the EF5 Moore tornado.  I have linked to their post for those interested in an insightful  discussion on the Tornado and its development

Jim Steenburgs Moore Tornado Discussion

Jeff Masters Moore Tornado Discussion

Rainfall Summary for the Period May 15-20

Rain Returns to the Cowboy State

Showers and some thunderstorms have brought much needed rain to Western and Central Wyoming last Wednesday night (May 15th) through this past Monday (May 20th).  The table below reflects final rainfall totals.

The following are Rainfall totals  for the period May 15-20.

Final Rainfall Totals 

County	Station Name	Rainfall

Lincoln	Afton	1.77
Lincoln	3 SE Bedford	1.73
Lincoln	Star Valley Ranch	1.70
Lincoln	5 SSE Smoot	1.56
Lincoln	1 SW Afton	0.70
Lincoln	Fossil Butte	0.48
Lincoln	21 NNW Kemmerer	0.29

Big Horn	2 SSW Lovell	0.51
Big Horn	Greybull	0.43
Big Horn	Greybull/South Big Horn Air	0.38
Big Horn	Shell	0.33
Fremont	Jeffrey City	1.74
Fremont	6 SW Lander	1.58
Fremont	Lander	1.29
Fremont	Lander Airport	1.27
Fremont	9 SSE Lander	1.23
Fremont	Lander	1.16
Fremont	Hudson	1.17
Fremont	10 WNW Dubois	0.92
Fremont	6 SE Lander	0.90
Fremont	Riverton Downtown	0.83
Fremont	Riverton Airport	0.79
Fremont	2 N Lander	0.68
Fremont	Burris	0.63
Fremont	Dubois	0.40
Fremont	Boysen Dam	0.31
Fremont	1 WSW Lander	0.18
Hot Springs	1 SW Thermopolis	1.11
Hot Springs	9 NE Thermopolis	0.99
Hot Springs	Thermopolis	1.46
Hot Springs	Kirby	1.23
Hot Springs	Thermopolis	0.96
Johnson	Buffalo Airport	1.04
Johnson	20 S Buffalo	0.93
Johnson	Billy Creek	0.82
Johnson	17 NNW Kaycee	0.61
Johnson	4 SSW Buffalo	0.66
Johnson	Buffalo	0.67
Johnson	Buffalo	0.43
Johnson	17 E Kaycee	0.07
Natrona	3 SW Casper	3.96
Natrona	4 WSW Casper	2.55
Natrona	2 S Casper	2.60
Natrona	1 SW Casper	2.39
Natrona	4 WSW Casper	2.28
Natrona	4 SW Casper	2.22
Natrona	11 ESE Casper	2.05
Natrona	Casper Near Airport	1.56
Natrona	Casper Airport	1.58
Natrona	10 WSW Casper	1.36
Natrona	11 WSW Casper	1.34
Natrona	Midwest	1.02
Natrona	Casper	2.45
Natrona	12 NE Lysite	0.21
Natrona	Casper	1.09
Park	Cody Area	1.42 - 1.89
Park	3 NE Sunshine	1.85
Park	3 NE Clark	1.56
Park	Powell Area	0.86 - 1.20
Park	Crandall Creek	1.02
Park	Meeteetse	0.85
Sublette	Daniel Fish Hatchery	0.76
Sublette	14 NW Pinedale	0.44
Sublette	13 SE Pinedale	0.48
Sublette	Boulder Rearing Station	0.33
Sublette	Big Piney Airport	0.25
Sweetwater	1 W Rock Springs	1.06
Sweetwater	1 E Rock Springs	1.06
Sweetwater	7 SSE Rock Springs	0.91
Sweetwater	Green River	1.00
Sweetwater	38 NW Superior	1.00
Sweetwater	5 N Farson	0.85
Sweetwater	Rock Springs Airport	0.36
Sweetwater	Buckboard Marina	0.19
Sweetwater	1 S Rock Springs	0.29
Teton	5 WNW Moran	1.09
Teton	4 SSW Jackson	0.82
Teton	Moose	0.77
Teton	2 NE Teton Village	0.75
Teton	Jackson	0.74
Teton	Moose	0.67
Teton	3 WNW Jackson	0.31
Washakie	16 SSE Ten Sleep	0.66
Washakie	8 SW Worland	0.48
Washakie	5 NNW Ten Sleep	0.39
Washakie	Worland ASOS	0.35
Yellowstone	Snake River Ranger Station	1.53
Yellowstone	Lake Yellowstone	1.07
Yellowstone	Old Faithful Ranger Station	1.03
Yellowstone	Tower Falls Ranger Station	0.79
Yellowstone	Yellowstone East Entrance	0.47
Yellowstone	Lamar Ranger Station	0.57

Moore Oklahoma Tornado

A devastating EF5 tornado struck Moore Oklahoma the afternoon of May 20, 2013.  There has been extensive media coverage including videos etc.  This post will provide a look at the radar data that was used to provide the life-saving warnings.

Following is the path of the EF5 tornado along with the additional two devastating tornado paths that have struck the Moore community in the past 14 years.

Tracks of 3 major tornados that have hit Moore OK since 1999.

The Oklahoma City Doppler radar shows both the reflectivity and velocity signatures at the time when the  EF5 damage was occurring.

The velocity image on the right shows the intense velocity couplet, while the reflectivity image on the left shows the huge debris ball about the time the tornado was destroying the Plaza Towers Elementary School.

Here is a link that will provide a time lapse of both the velocity and reflectivity of the storms as it track from Newcastle eastward across Moore OK.

Radar animation of the Twin Lakes 88-D radar


The official statement issued by the Norman Forecast Office Tuesday follows

Public Information Statement Issued by NWS Norman
for the Tornado Outbreak of May 20, 2013

PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE NORMAN OK 250 PM CDT TUE MAY 21 2013 ...NWS DAMAGE SURVEY FOR 5/20/2013 NEWCASTLE/MOORE TORNADO EVENT - UPDATE 3... ...NWS DAMAGE SURVEY HAS NOW RATED THE NEWCASTLE/MOORE TORNADO AS EF5... .OVERVIEW... THE NATIONAL WEATHER SERVICE DISPATCHED FOUR DAMAGE SURVEY TEAMS TO THE PATH OF THE NEWCASTLE/MOORE OK TORNADO. NEW STATEMENTS WILL BE ISSUED THROUGHOUT THE DAY AS THESE TEAMS REPORT FINDINGS. THIS INFORMATION REMAINS PRELIMINARY AND THE INFORMATION HERE COULD CHANGE. .NEWCASTLE/MOORE TORNADO RATING: EF5 ESTIMATED PEAK WIND: 200-210 MPH PATH LENGTH /STATUTE/: 17 MILES PATH WIDTH /MAXIMUM/: 1.3 MILES FATALITIES: N/A INJURIES: N/A START DATE: MAY 20 2013 START TIME: 2:45 PM CDT START LOCATION: 4.4 W NEWCASTLE /GRADY COUNTY /OK START LAT/LON: 35.2580 / -97.6775 END DATE: MAY 20 2013 END TIME: 3:35 PM CDT END LOCATION: 4.8 E OF MOORE OK /CLEVELAND COUNTY /OK END LAT/LON: 35.3409 / -97.4007 SURVEY SUMMARY: EXPERTS SURVEYING IN MOORE HAVE DETERMINED DAMAGE IS EF5 WITH MAXIMUM WINDS OVER 200 MPH. FOUR SURVEY TEAMS CONTINUE TO INSPECT DAMAGE FROM THIS LONG TRACK TORNADO. INITIAL DAMAGE WAS FOUND AROUND 4.4 MILES WEST OF NEWCASTLE...SOUTH OF TECUMSEH ROAD ALSO KNOWN AS NW 16TH STREET AND EAST LAKE ROAD. THE TORNADO TRACKED NE TO THE INTERSTATE 44 BRIDGE OVER THE CANADIAN RIVER AND THEN TOOK A MORE EASTWARD TRACK THROUGH MOORE. TORNADO DAMAGE ABRUPTLY ENDS 0.3 MILES EAST OF AIR DEPOT ROAD AND N OF SE 134TH ST. INITIALLY PRODUCING EF0 AND EF1 DAMAGE THE STORM INTENSIFIED VERY RAPIDLY IN 4 MILES OR AROUND 10 MINUTES PRODUCING EF4 DAMAGE BEFORE REACHING INTERSTATE 44. NUMEROUS INDICATIONS OF EF4 DAMAGE WITH SOME AREAS NOW DETERMINED AT EF5 DAMAGE...THE HIGHEST CATEGORY ON THE EF SCALE...WITH OVER 200 MPH WINDS. ADDITIONAL INFORMATION SUCH AS MAXIMUM PATH WIDTH WILL BE UPDATED AS THE TEAMS COMPLETE THEIR SURVEYS.

Funnel Cloud Star Valley?

This photo was taken at 5:15pm Thursday looking west at the intersection of Highway 89 and Cedar Road near Star Valley Ranch.  Little if any rotation was observed and it dissipated shortly after photo.

Earthquake Magnitude Lowered to a 3.6

2013 Spotter Training Thursday May 16th

The annual SpotterTraining conducted by the Riverton Forecast Office is being presented in Afton at the Civic Center today, Thursday May 16th at 6PM.  It is an excellent presentation on how to identify Severe Thunderstorms.

Supercell Thunderstorm

Supercell Thunderstorm

The National Weather Service relies on trained volunteers to supplement doppler radar information when severe storms and tornadoes threaten. These dedicated individuals volunteer their time to learn about and detect severe weather. Their valuable cooperation is important in the warning process. Weather reports from trained spotters are used along with doppler radar data to issue warnings of tornadoes, severe thunderstorms, and flash floods.

Severe Weather Spotter Talk Schedule

Below is a listing of upcoming severe weather spotter talks...

  

May, 2013 - Upcoming
Day	City, State	Time	Location
16	Afton, WY (Lincoln County)	6:00pm MDT	Civic Center 150 South Washington
	Contact Information: Bill.Murrell@noaa.gov
21	Lander, WY (Fremont County)	6:00pm MDT	BLM, 1335 Main Street
	Contact Information: katy.branham@noaa.gov
23	Big Piney, WY (Sublette County)	6:00pm MDT	Big Piney/Marbleton Fire Hall, 203 Main Street in Marbleton
	Contact Information: Bill.Murrell@noaa.gov

4,0 Earthquake Rocks Star Valley

An earthquake occurred around 11:23 PM MDT just to the west of Star Valley.  The preliminary strength from the USGS was magnitude 4.0 on the Richter Scale. The epicenter was about 10 miles WNW of Afton WY.  It was felt at Star Valley Ranch with two sharp jolts.

Near Record Warmth on Monday will speed up Snow Melt

Temperatures in Star Valley will likely reach into the low 80's on Monday after a perfect Mothers Day Sunday with 70's. At Star Valley Ranch the warmth has quickly pushed the Aspens into leafing out the past couple of days.

 

Near-record highs for Monday

A warm ridge of high pressure is forecasted to be over Wyoming on Monday, May 13. This will result in possible record high temperatures across much of the area.
Sunday, May 12, 2013
Location	Forecasted High Temperature °F	Current Record Temperature °F / Year
Casper - Natrona County International Airport	79	87 / 1960
Lander - Hunt Field	79	86 / 1960
Riverton - Downtown	80	89 / 1962
Rock Springs - Sweetwater County Municipal Airport	77	82 / 1960
Worland - Municipal Airport	83	92 / 1960
Monday, May 13, 2013
Location	Forecasted High Temperature °F	Current Record Temperature °F / Year
Casper - Natrona County International Airport	87	87 / 2001
Lander - Hunt Field	85	86 / 2001, 1988
Riverton - Downtown	86	88 / 2007
Rock Springs - Sweetwater County Municipal Airport	81	80 / 1996
Worland - Municipal Airport	90	92 / 2001

Also of concern heading into Monday will be rising water levels in some of the area rivers/creeks.  Temperatures will be rising consecutively over the weekend, so increased snowmelt is expected. The Spring Snowmelt Flood Potential Outlook in addition to the latestWater Supply Outlook, will help identify those areas that may be more susceptible for these expected water rises.

Summer Like Temperatures by Monday?

The video briefing for the next several days promises temperatures rising to near summer like levels by Monday!.

Weather Briefing From Riverton WFO

Spring Snowstorms Come Through for Wyoming

It has been a very beneficial Spring snow season for all of Wyoming this year.  At Star Valley Ranch the total of 172 inches since October 1, 2012 compares closely with last years 175 inches.

Of more importance are the snow pack in the mountains which are just now beginning the melting process as temperatures warm.  Following are the graphs for both the Willow Creek and Cottonwood Creek SNOTELS in the nearby Salt Range.

Willow Creek SNOTEL

Cottonwood Creek SNOTEL

While western Wyoming has fared well  the eastern portion of the state has show remarkable improvements due to several big storms, particularly in April.

Following are two maps, the first the snow pack as of March 1st and the other, May 1st.  The improvements in the eastern portion of the state are dramatic!

Weekend Weather Briefing and Storm Summary

Riverton WFO is providing their weekly briefing of the upcoming weekends weather.  It can accessed through the following link

Weekly Video Weather

Additionally Riverton WFO has issued a summary of the most recent storm that affected the Cowboy State.

Summary of the May Snow storm