Thursday, October 23, 2014

Changes to Cooler and Wetter on the Way

The Riverton Forecast Office in their weekly weather video are highlighting the changes to possibly snow by the end of the weekend.

Weekly Weather Video

Monday, October 20, 2014

Repost of Wyoming Record Low Temperature Location

A couple years ago a blog discussed the controversy of where the Wyoming record low temperature occurred. With winter approaching, that particular blog is reposted below.


While recent weather records are typically quite accurate given the modern day instrumentation and GIS capabilities, errors are being found in some of the older ones.  A couple of  examples that have been noted recently in this blog are the Worlds highest temperature

and the location of the historic Teton Tornado in 1987

Another record that has been questioned recently is the Wyoming all-time coldest temperature.  There is a blog that addresses this and other very interesting global record cold sites.

For many years there has been confusion surrounding the actual location of the Riverside Ranger Station that recorded a temperature of -66°F on Feb. 9, 1933. This figure has long been erroneously reported as the coldest temperature ever measured in Wyoming (See NCDC site for instance). The problem is that this (no longer existing) ranger station was actually located in the Montana section of Yellowstone National Park. It was situated where the town of West Yellowstone, Montana now resides.

The reason for this confusion originates from the fact that theClimatological Data by Sections USWB report for February 1933 includes Yellowstone National Park in its Wyoming section even though portions of the park, including the site of Riverside R.S., are in Montana and Idaho. If one looks at the station I.D. number (248857) on the Western Regional Climate Center’s station summaries lists we see that the site was established in 1924 (when the ranger station was established) and then continues at the same location in later years as “West Yellowstone, Montana”.

Also, I have personally(Christopher Burt the blogger) visited this area and investigated the location of the ranger station and can confirm that the site was in Montana when it was built in 1924 (by only 200 yards!). The actual record low for the state of Wyoming is -63°F at Moran on that same night of Feb. 9, 1933.

This map from 1929 shows the exact location of the Riverside Ranger Station. It is just sandwiched between the border of the national park (the large green border) and the border between Wyoming and Montana (the small dashed border). The name of the ranger station is not given, it just says "ranger station" but this is, in fact, the Riverside Ranger Station (named 'Riverside') because it is by the Madison River. One can understand the confusion of the location so far as being in Wyoming or Montana.

Friday, October 17, 2014

Winter 2014-2015 Outlook Issued

The Climate Prediction Center has issued their outlook for the winter months of December through February.  They are expecting a weak El Nino Pattern for this winter much puts Wyoming in the indeterminate area for both precipitation and temperatures.  Following is the forecast and discussion from the NOAA Climate Prediction Center.

NOAA: Another warm winter likely for western U.S., South may see colder weather

Repeat of last year’s extremely cold, snowy winter east of Rockies unlikely

October 16, 2014
(Credit: NOAA)
Below average temperatures are favored in parts of the south-central and southeastern United States, while above-average temperatures are most likely in the western U.S., Alaska, Hawaii and New England, according to the U.S. Winter Outlook, issued today by NOAA’s Climate Prediction Center.

While drought may improve in some portions of the U.S. this winter, California's record-setting drought will likely persist or intensify in large parts of the state. Nearly 60 percent of California is suffering from exceptional drought – the worst category – with 2013 being the driest year on record. Also, 2012 and 2013 rank in the top 10 of California’s warmest years on record, and 2014 is shaping up to be California’s warmest year on record. Winter is the wet season in California, so mountainous snowfall will prove crucial for drought recovery. Drought is expected to improve in California’s southern and northwestern regions, but improvement is not expected until December or January.
“Complete drought recovery in California this winter is highly unlikely. While we’re predicting at least a 2 in 3 chance that winter precipitation will be near or above normal throughout the state, with such widespread, extreme deficits, recovery will be slow,” said Mike Halpert, acting director of NOAA’s Climate Prediction Center. “This outlook gives the public valuable information, allowing them to make informed decisions and plans for the season. It's an important tool as we build a Weather-Ready Nation.”

El Niño, an ocean-atmospheric phenomenon in the Tropical Pacific that affects global weather patterns, may still develop this winter. Climate Prediction Center forecasters announced on Oct. 9 that the ocean and atmospheric coupling necessary to declare an El Niño has not yet happened, so they continued the El Niño Watch with a 67 percent chance of development by the end of the year. While strong El Niño episodes often pull more moisture into California over the winter months, this El Niño is expected to be weak, offering little help.
(Credit: NOAA)
The Precipitation Outlook favors above-average precipitation across the southern tier, from the southern half of California, across the Southwest, South-central, and Gulf Coast states, Florida, and along the eastern seaboard to Maine. Above-average precipitation also is favored in southern Alaska and the Alaskan panhandle. Below-average precipitation is favored in Hawaii, the Pacific Northwest and the Midwest.
Last year’s winter was exceptionally cold and snowy across most of the United States, east of the Rockies. A repeat of this extreme pattern is unlikely this year, although the Outlook does favor below-average temperatures in the south-central and southeastern states.

In addition, the Temperature Outlook favors warmer-than-average temperatures in the Western U.S., extending from the west coast through most of the inter-mountain west and across the U.S.-Canadian border through New York and New England, as well as Alaska and Hawaii.
Video: Winter Outlook 2014-2015. (Credit: NOAA)
The rest of the country falls into the “equal chance” category, meaning that there is not a strong enough climate signal for these areas to make a prediction, so they have an equal chance for above-, near-, or below-normal temperatures and/or precipitation.
The U.S. Seasonal Drought Outlook, updated today and valid through January, predicts drought removal or improvement in portions of California, the Central and Southern Plains, the desert Southwest, and portions of New York, Connecticut, Rhode Island and Massachusetts. Drought is likely to persist or intensify in portions of California, Nevada, Utah, Idaho, Oregon and Washington state. New drought development is likely in northeast Oregon, eastern Washington state, and small portions of Idaho and western Montana.

This seasonal outlook does not project where and when snowstorms may hit or provide total seasonal snowfall accumulations. Snow forecasts are dependent upon the strength and track of winter storms, which are generally not predictable more than a week in advance.
NOAA's mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Join us on TwitterFacebookInstagram and our other social media channels.

Sunday, October 12, 2014

Water Vapor Imagery-Use and Misuse

Of the many bands of imagery provided by GOES satellites that orbit above the equator is water vapor.  It is a valuable observational tool but not with regards to actually measuring water content in the atmosphere.  

Water Vapor Imagery Sunday AM October 12 2014

The  Wasatchweatherweenies  blog provides an informative discussion of what the use of Water Vapor Imagery and what it actually observes.

Use and Misuse of Water Vapor Imagery

Water vapor satellite images are frequently misused and misinterpreted.  Here's a very basic primer.

Water vapor images do not measure water vapor and they certainty do not measure water vapor in the lower atmosphere where it plays an important role in the development of precipitation systems.  Water vapor imagery is simply based on a band of infrared radiation that is absorbed and emitted by water vapor.  This contrasts with the band of infrared radiation sampled by conventional infrared satellite images which is largely unaffected by the presence of water vapor or other atmospheric gases.

As a result, water vapor imagery is strongly influenced by the distribution, temperature, and concentration of clouds and water vapor in the upper troposphere, typically at altitudes above 500 mb (5500 meters).  A prime example is the water vapor loop below, to which I've added contours of precipitable water (i.e., total integrated water vapor).  Note the northward spread of cirrus clouds and upper-level moisture from into Utah over the past two days.  As ominous as this looks, it is simply a very thin, cold layer of clouds and moisture.  The juicy air associated with tropical storm Simon remains well to the south, as indicated by the precipitable water contours, and is just beginning to push across the US–Mexico border.  

Even areas in red above, which many people interpret as "dry" can overlay areas of abundant low-level moisture.  Those are areas that are dry and warm in the upper atmosphere, but not necessarily in the lower atmosphere.  For example, in the wake of tropical storm Simon, the upper-levels are very dry and warm, but the precipitable water values are fairly high due to abundant low-level moisture.

One of the major advantages of water vapor imagery is the ability to track water vapor features in areas that are cloud free.  This is extremely useful for inferring upper-level winds when no clouds are present.  One can also identify smaller-scale upper level features such as short-wave troughs using water vapor imagery.  These are effective applications of water vapor imagery.  The use of water vapor imagery to infer low-level water vapor concentrations is, however, dubious and should be avoided. 

Thursday, October 9, 2014

Cool Down This Weekend-Video

A break in the beautiful Fall weather is coming this weekend to Wyoming

Here is a video from Riverton Forecast Office discussing the change

Video Weather Briefing