Weekend Weather Forecast for the Resorts in northern Utah, western Colorado and souther Idaho

Discussion: High pressure will rule this weekend with temperatures above normal for the first weekend in fall.

Forecast: Daytime skies will be sunny and nights moony. Afternoon winds light

Today / Friday /Saturday
Park City/Deer Valley 75 80/40 85/45

Vail/Beaver Creek 66 68/40 73/40

Sun Valley/Ketchum 67 75/38 75/38

Shine on Harvest Moon

A large, full moon will herald in the fall as it graces the skies on the autumnal equinox for the first time in nearly 20 years.

Today is the last day of summer, and as the sun sinks into the western horizon, the Harvest Moon will rise in the east, creating a 360-degree, summer-autumn twilight that is rarely seen, said Tony Phillips of Science@NASA.

The moon may appear much wider than normal due to the moon illusion that is still not understood by astronomers or psychologists.

“A Harvest Moon inflated by the moon illusion is simply gorgeous,” Phillips said. “The view improves as the night wears on.”

Autumn officially begins at 9:09 p.m. in Utah, and at that time the moon will be overhead with Jupiter just next to it.

“The two brightest objects in the night sky will be in spectacular conjunction to mark the change in seasons,” Phillips said.

Typically, the Harvest Moon arrives within days or weeks of the autumnal equinox, but rarely does it align perfectly. The Harvest Moon of 2010 reaches its maximum illumination only six hours after the official start of fall. There hasn’t been a comparable coincidence since Sept. 23, 1991, when the moon was brightest 10 hours from the equinox. Such an alignment won’t happen again until 2029.

Autumnal Equinox or the 1st Day of Fall Sept 23

The autumnal equinox or the first day of fall arrives tomorrow, September 23rd at 9:09 MDT. On this day the sun is directly of the equator as the earth tilts away from the sun toward winter in the northern hemisphere. Day and nights are equal and the sun rises exactly in the west and sets exactly in the east. This day is the first day of spring in the southern hemisphere.

Another bid of trivia is that the ancients used this day to set-up their calendar at Stonehenge and at the Mayan pyramid.

Parking Allowed on Sidewalks in Park City's Old Town

City Hall will allow people to park on the sidewalks on a small stretch of road in Old Town, the first time Park City officials have allowed the practice.

Brooks Robinson, the senior transportation planner for City Hall, said the easing of the parking restrictions affects Norfolk Avenue between 8th Street and 12th Street. According to Robinson, the changes are:

Between 8th Street and 10th Street, parking will be allowed on the sidewalk on the east side of the street. Robinson said loosening the restrictions creates approximately 30 parking spots.

Between 10th Street and 12th Street, parking will be allowed on the sidewalk on the west side of the street, creating approximately 18 spots.

Parking on sidewalks is prohibited elsewhere in Park City, and officials expect to modify the municipal code to reflect the Norfolk Avenue change.

Why the Leaves Turn Color in the Fall

The turning leaves of deciduous trees are a welcome sign of autumn and its longer, cooler nights. Vibrant reds, yellows, and oranges make up the color scheme of fall, and they are all part of the cyclical nature of the seasons. Leaves on trees, shrubs,and plants turn colors when they begin the process of going dormant for the winter and before the white stuff starts to fly.

Once the days and nights begin to cool and the nights get longer, the trees sense that fall and winter are approaching. In the trees' preparation to go dormant, circulation to the leaves, which are no longer needed to produce food, is cut off. Due to the long nights and reduced sunlight, the production of chlorophyll is reduced, meaning that the green will eventually disappear fromthe leaves. Some of the pigments responsible for causing the vibrant colors in the leaves, such as carotenoids, are in the leaves. but are obscured by the green chlogophyll. Carotenoids are responsible for yellows, orange and browns.

The trees in the Sawtooth range of southern Idaho, the Wasatch of northern Utah, and the Rockies of Colorado are turning now and will reach their peak this month into the first part of October.

La Nina Update as of Sep 9th

La Nina strengthen during August 2010, as negative sea surface temperature (SST) anomalies reached at least 1 deg C across most of the equatorial Pacific by the end of the month. It was noted that there was a enhancement of the low-level easterly trade and anomalous upper-level westerly winds over the western and central equatorial Pacific. What all this means is that oceanic and atmospheric anomalies reflect the strengthening of La Nina.

Nearly all models predict La Nina to continue at least through early 2011. However they disagree on the eventual strength.

Will continue to update La Nina conditions each month into the fall and winter of 2010-2011.

La Nina supports a active northern storm trace that would enhance precipitation over Idaho and northern Utah.

4-day Labor Day Weekend Weather Forecast for Sun Valley/Ketchum

Discussion.. A fall type storm will be moving through southern Idaho over the Labor Day weekend.

Today.. Sunny with highs in the upper 70s. Lows 40-45.

Saturday.. Becoming partly cloudy with a slight chance of showers late. Highs in the upper 70s. Lows 40-45. Winds 20-30 mph at times.

Sunday.. Partly cloudy with a 20-30% of showers and thunderstorms and turning much cooler. Highs only near 60. Lows 30-35.

Labor Day.. Partly cloudy with a chance of rain or snow (yes snow) showers. Highs 55-60. Lows 30-35. Main snow level will be about 6500-7000 feet in the moderate showers.

4-day Labor Day Weekend Weather Forecast for Vail/Beaver Creek

Discussion.. Dry fall weather is expected into the long weekend with a weather system ushering in some cooler air on Labor Day.

Today through Sunday.. Sunny days and clear nights. Highs in the mid to upper 70s. Lows in the lower 40s. Breezy on Sunday.

Labor Day.. Partly cloudy with highs in the mid 60s. Lows 35-40. Breezy.

4-day Labor Day Weekend Weather Forecast for Park City/Deer Valley

Discussion.. Another fallish type weather system will be moving into northern Utah with a dramatic drop in temperature on Labor Day.

Today through Sunday.. Sunny days and mostly clear nights. High today mid 80s.. Saturday near 90 and Sunday near 80. Lows lows near 50. Breezy on Sunday.

Labor Day.. Partly cloudy with much cooler with highs in the mid 60s and lows near 40.

Note.. The mountains have started turning color.

Major Changes at The Canyons Ski Resort

The Canyons will be just called "Canyons" by opening day in the 2010-2011 ski season. Many other changes are in store in the next 15 months. Read more:

http://www.parkrecord.com/ci_15842707?source=most_viewed