Archive for February, 2008

Weekend Changes……Snow Monday?
February 28, 2008

A ridge of high pressure aloft will dominate our pattern over the next several days, unfortunately, that won’t last forever as winter returns for Monday! You can see the ridge pictured above. This is what we call a very “amplified” pattern.

The ridge will hold through Sunday, keeping temperatures above average.

All good things must come to an end though. Here’s the trough digging south for Sunday. Look at the cold air to the northwest that’s set to come through for Monday.

There’s the potential for rain to change over to snow by Monday afternoon, so we’ll be monitoring that closely.

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THURSDAY WARM UP…
February 28, 2008


A warm front will be sweeping across the area today and will bring warm temperatures. Southeast Oklahoma and Southwest Arkansas could experience afternoon highs in the upper 60s! If you are unable to get outdoors today, don’t worry about it. Temperatures will continue to be warm all the way through the weekend. A cold front arrives Sunday night and provides a good chance for showers and thunderstorms. Some of those storms could be strong, so keep checking the weather blog for the latest updates about the severe weather possibilities.

Countdown to Spring……..
February 28, 2008

Even though Spring is several weeks away, the upcoming weather may have you jumping seasons! The upper level pattern is starting to become very amplified; look at the monster ridge that’s forecast to move over the plains. This will allow our temperatures to remain above average! This ridge will keep the real cold air at bay to the north; however, with an amplified pattern, you can eventually count on a cold snap to follow the warmth!

The 850 mb temperatures seen below really show the warming trend throughout the weekend. This level of the atmosphere can really show trends of warming and cooling.

MUCH COLDER TODAY!
February 26, 2008

The cold front that moved through the area Monday night and Tuesday morning not only gave us very strong winds, but it also caused a major change in our temperatures. Here is a look at the 24 hour temperature change for our morning lows. So this compares where we were Monday morning to where we were Tuesday morning. It’s a great tool to show the progress and strength of cold fronts and warm fronts across the U.S. over a 24 hour period.

Buried To The Roof…
February 25, 2008

This is the roof of the Paradise Inn at Mt. Rainier National Park in Washington State. Get this… thus far over the winter season, the park has picked up some 621″ of snow. THAT’S NEARLY 52 FEET OF SNOW!

NOW THAT’S A LOW!
February 25, 2008

This animation is from noon on Friday, 2/22/2008, through noon on Sunday,2/24/2008. CHECK OUT THE EVOLUTION OF THE LOW(S)!
There are actually two in the shot… both are quite impressive! The “main” one and closest to the States, (big counter clockwise spinning mass of clouds that pushes into Northern California at end of loop) was kicking up waves to 30 feet! White out conditions hit the Sierra Mountains and up to a foot and a half of snow fell as this pushed in-land. The storm lost much of its “Hurricane-like” shape through Sunday, but a re-development just north of us will be looking impressive too! Parts of the northern plains and Great Lakes are under the gun for Snow, Sleet and generally adverse driving conditions. We’ll get some wind along with a few showers and possibly a rumble of thunder. In fact, wind gusts already have been high, with Fayetteville reporting gusts up to 33 mph! As this system pushes eastward expect a cold wind out of the North to usher in, reminding us that the calendar still says February.

BIG CHANGES THIS WEEK!
February 25, 2008


The Jetstream has been very active over the past several weeks and the week ahead is no exception to the trend! A powerful Low and associated upper level trough has pushed into the country from the west. On Saturday this surface Low looked like a Hurricane while spinning in the Pacific just off the California coast. The storm has since lost its shape but a good bit of Jetstream energy is helping to develop a new surface Low just east of the Rockies. This too will wrap up a good bit and gain strength. The biggest effect it will have on us will be a significant temperature drop as it drags a cold front through late Monday along with a bunch of wind. Prior to this we’ll be above average with widespread 60s, but by Tuesday we’ll be back in Winter with chilly highs in the upper 30s to middle 40s, some five to ten degrees below seasonal averages. Couple these temps with gusts perhaps as high as 30 to 40 mph and it will be feeling like upper 20s and 30s! Friday looks to bring in another trough to our area and the likelihood of some rain. Late Sunday brings in yet a third system, which may dig far enough to the south to tap into abundant moisture. Should this be the case and a great enough temperature contrast is present, we may be contending with a round of strong to severe t-storms. We’ll be monitoring this threat through the week.

La Nina
February 22, 2008

La Nina conditions; a cooling trend of waters along the equatorial Pacific, have continued to be a feature into 2008. Recent dynamical and statistical sea surface temperature (SST) forecasts indicate a moderate to strong La Nina through the rest of the Northern Hemisphere winter with a continuation into the spring. *Side bar: Note the plume of warmer SST’s, (infering rising motion, moisture and storms) plowing into the Pacific NW! Can you say ridiculous amounts of snow!? Lots and Lots So, the $64,000 question is… OK, we’ll get with modern times and make it a $1,000,000… So, the million dollar question is what does this all mean for us?

Precipitation-wise, we tend to be a little below average under such conditions. January was very dry. February, thanks to the rain of Feb. 16-17, has been wet. Slight chances of rain are in the extended forecast now, but we’re not looking at any gully-washers! Temperature-wise, La Nina conditions tend to keep us a little warmer than average. We have dodged a few potentially devastating ice events… so; we’ll see what the rest of the winter has in store.

Libration
February 22, 2008


We missed out on seeing the lunar eclipse last night due to the clouds, but here’s an interesting fact about viewing the visible moon and a very cool picture to go with it! Through a process known as Libration it is possible to “view” more than 50% of the visible surface which is tidally locked in a fixed position relative to Earth.

There are three types of libration:

Libration in longitude is a consequence of the Moon’s orbit around Earth being somewhat
eccentric, so that the Moon’s rotation sometimes leads and sometimes lags its orbital position.

Libration in latitude is a consequence of the Moon’s axis of rotation being slightly inclined to the
normal to the plane of its orbit around Earth. Its origin is analogous to the way in which the seasons arise from Earth’s revolution about the Sun.

Diurnal libration is a small daily oscillation due to the Earth’s rotation, which carries an observer first to one side and then to the other side of the straight line joining Earth’s center to the Moon’s center, allowing the observer to look first around one side of the Moon and then around the other.

SLEET NEAR HUNTSVILLE
February 21, 2008

This shot of some sleet was sent in from a weather tracker in the Huntsville area. The depth of the cold air in our area has not been sufficient for snow. In fact, aloft at some 5000′, temperatures are well above freezing. So, rain, perhaps melting from snow higher up, in essence is falling into a below freezing layer of air and producing some sleet and freezing rain where there is just a very shallow layer of cold air.