KMTR Weather Blog

New Record Low

2009-10-07T18:18:00Z

The clear sky Tuesday morning helped Eugene set a new record low of 29! The old record was 32. It was Eugene’s first time with freezing temperatures this fall.

The weather still looks mild through the weekend. I expect patchy morning fog and low clouds, but afternoon sunshine now through Sunday. By Monday night, a system will start bringing a chance of rain and it looks much cooler and wetter by Tuesday.

-KMTR Meteorologist Brent Prasnikar

Long Dry Spell

2009-10-06T18:12:00Z

Our weather pattern looks very dry for the extended period. Today’s models were hinting at a chance of rain next Tuesday, October 13th. Unless there’s a big change, the ridge will maintain sunny days and mostly clear nights with the exception of patchy morning fog and low clouds in the valleys of western Oregon.

-KMTR Meteorologist Brent Prasnikar

New Rain Season, Rain Total and Rain Averages

2009-10-01T14:13:00Z

Today is October 1^st and that means it’s the start of a new rain season. Eugene ended the last rain season nearly 22 inches less than the average rainfall total. However, weather and climate fans will continue debating whether what is considered “normal” or “average” is an accurate reflection of what really is Eugene’s average. Much of that debate involves the new rain gauge installed in Eugene in 1996. That same year, NWS officially corrected Eugene’s rain total to 101.93”. That’s 35” more than what fell in Salem that same period.

For more information about this go to http://zebu.uoregon.edu/raining.html

Anyway, looking ahead, the second graphic above shows the average rainfall each of the next three months. November and December are statistically Eugene’s two wettest months.

I will be attending the annual meeting “What will winter be like in Oregon” on October 17^th. I'm looking forward to hearing what climatologists are predicting and sharing it with you on the following Monday. We’ll see if they expect wetter, drier, warmer or cooler conditions this year.

-KMTR Meteorologist Brent Prasnikar

End of the Rain Season

2009-09-30T14:23:00Z

At first glance, seeing that Eugene is nearly 22” below its normal rain total seems quite alarming. However, Eugene’s rain totals have been remarkably low for many years. The huge deficits seem to begin when the National Weather Service switched the official rain gauge during the 90’s. They think the old gauge over-measured, so it will take some time to collect enough data on this new gauge to accurately reflect the real rain averages.

The rain season ends today, so I'll know our exact totals tomorrow.

-KMTR Meteorologist Brent Prasnikar

Showers with a chance of Tstorms

2009-09-29T14:33:00Z

I am expecting our first dose of the more traditional fall weather in western Oregon. Today looks very cool with showers. We may even get a cold-air thunderstorm from all the instability showers. It looks like this system will bring the Cascades its first dose of snow, but it won’t stick around at pass level.

Wednesday and Thursday look a little bit warmer and dry, but rain returns Friday with cold and showery weather on Saturday.

Tomorrow is the last day of our rain season. The new season begins October 1^st. I’ll blog the final total when it’s available. As usual, it looks like Eugene will end the season more than one and a half feet below our seasonal average.

-KMTR Meteorologist Brent Prasnikar

Recalibrating what’s “warm”

2009-09-25T17:30:00Z

Now that it’s officially fall, it’s time to start acclimating to cooler weather. Much of this week's weather has been a lot warmer than average. This weekend, the average high in Eugene is 73 Saturday and Sunday. It’s 72 by Monday. This weekend’s weather looks sunny with relatively warm in the afternoons (near 80) after cold mornings (near 40) with patchy fog.

Big change is coming Monday night as the first fall storm arrives in western Oregon. It looks like it will bring snow lines down to around pass level in the Cascades (4,000’ to 5,000’) I expect decent rain followed by showers in the inland valleys. Highs in Eugene only near 60 by Tuesday.

-KMTR Meteorologist Brent Prasnikar

Wildfire effect on the forecast

2009-09-23T13:54:00Z

The above image is the satellite technology normally used to detect fog overnight. I think it’s cool how you can clearly see the two black “holes” where the Tumblebug Complex and Boze Fire are burning this morning.

Smoke from the fires made the sky look like it was dusk through much of the afternoon in Eugene yesterday. Smoke from the Boze fire was aimed primarily at the southern end of the Willamette Valley. Tumblebug Complex fires sent smoke a little farther north.

The smoke definitely messed with the forecast. It scattered some of the incoming solar radiation that otherwise would have increased our temperatures. Yesterday’s official high in Eugene was just 89 degrees. Many models (and this meteorologist) forecast highs of 95. I do take some comfort believing that we would have hit 95 without the smoke. Roseburg remained smoke-free yesterday and did set a new record high at 101.

-KMTR meteorologist Brent Prasnikar

More record high temperatures?

2009-09-21T14:34:00Z

A heat wave will give western Oregon hot afternoon conditions through Wednesday. Tuesday will be the hottest day. It’s Eugene’s best chance to tie or set a new record high temperature.

A look at Tuesday’s forecast high temperatures by the numbers as of 10:00 a.m. Monday…

GFS=91

NAM=96

NWS=96

Brent=96

The timing of this is kind of fun, because we officially end summer Tuesday with the Autumnal Equinox at 2:18 p.m. PDT. It looks as though the summer-like weather is not going to end any time soon. The hottest part of the 7 day forecast is early this week, but long range models still show relatively warm and mostly sunny weather through this weekend.

-KMTR meteorologist Brent Prasnikar.

Showers vs. Rain

2009-09-17T15:54:00Z

It's been a long while since the last blog entry. I’ve been working a lot of shifts out of my normal schedule. Anyway, let’s get to it…

I want to answer a common question: "What's the difference between rain and showers?"

The greatest distinguishing factor is the process by which the precipitation is created; NOT the intensity or total accumulation.

Showers are a specific kind of rain produced by small-scale processes in an unstable air mass. Showers produce abrupt changes as individual cells pass over a small area during a brief time span. They are often catagorized as "on and off" quickly changing the weather for a given location.

When you hear "Rain" in a forecast, it usually refers to a large-scale weather feature, like a front, with precipitation that is more continuous over a broad region.

-KMTR Meteorologist Brent Prasnikar

Further reading: Definitions from the glossary of the American Meteorological Society…

shower—Precipitation from a convective cloud. Showers are characterized by the suddenness with which they start and stop, by the rapid changes of intensity, and usually by rapid changes in the appearance of the sky. In weather observing practice, showers are always reported in terms of the basic type of precipitation that is falling, that is, rain showers, snow showers, sleet showers. In aviation weather observations, these are encoded RW, SW, and EW, respectively. See airmass shower.

rain shower—A brief period of rainfall in which intensity can be variable and may change rapidly. It is often convective in nature.

rain—Precipitation in the form of liquid water drops that have diameters greater than 0.5 mm, or, if widely scattered, the drops may be smaller. The only other form of liquid precipitation, drizzle, is to be distinguished from rain in that drizzle drops are generally less than 0.5 mm in diameter, are very much more numerous, and reduce visibility much more than does light rain. For observing purposes, the intensity of rainfall at any given time and place may be classified as 1) "light," the rate of fall varying between a trace and 0.25 cm (0.10 in.) per hour, the maximum rate of fall being no more than 0.025 cm (0.01 in.) in six minutes; 2) "moderate," from 0.26 to 0.76 cm (0.11 to 0.30 in.) per hour, the maximum rate of fall being no more than 0.076 cm (0.03 in.) in six minutes; 3) "heavy," over 0.76 cm (0.30 in.) per hour or more than 0.076 cm (0.03 in.) in six minutes.

Go Ducks!

2009-09-03T18:09:00Z

As a U of O graduate, I’m excited about the game tonight. There’s a lot of hype. I keep hearing people say, “It’s like a bowl game to start the season.”

Weather will be sunny and warm in Boise. High near 92 today, but upper 80's at kickoff.

In addition to predicting weather, I’ll predict a score… Ducks win 52-31 (maybe just wishful thinking) Go Ducks!

-KMTR Meteorologist Brent Prasnikar

Wet Weekend, Wet Eugene Celebration

2009-09-02T14:30:00Z

The people who organized this year’s Eugene Celebration must have done something to cross Mother Nature. They scheduled this year’s event one week earlier than last year. Climatologically, the move gave the event a better chance of being warmer with more sunshine. However, a much cooler and wet weekend looks like a sure bet at this point.

The above image is today’s 06z GFS 6 Hour Rainfall for Saturday at 5:00 p.m. P.D.T. If the model has it right, western Oregon will be the wettest part of the nation this time period. A cold front will bring rain followed by showers.

Friday night still looks dry for the first day of the event. The rain just presents a great opportunity for people in Eugene to prove that you can have a great time regardless of the weather conditions.

-KMTR Meteorologist Brent Prasnikar

Dry August, Year and Rain Season

2009-09-01T14:21:00Z

August ended with a trace amount of rain from last night’s showers over Eugene. It is usually our driest month of the year and this year was even more so than normal. The total of 0.12” of precipitation is well shy of the August average of 0.99” of precipitation.

We are in an El Nino pattern heading into the fall. That pattern typically means drier than normal conditions for the Pacific Northwest. It’ll be fun to watch and see whether our “dry” trend continues into the new rain season, which begins in October.

We did it!

2009-08-20T17:11:00Z

We made it! Not only did we set the new record high temperature for Eugene… I get a bonus point for nailing it on the button (see previous post). That was definitely the peak heat. Morning clouds formed in the southern Willamette Valley today, but they’ll clear for a mostly sunny afternoon. I expect more of the same the next few days. High temperatures will continue cooling to near seasonal averages, or just less than that, now through the weekend.

-KMTR Meteorologist Brent Prasnikar

Close, but no cigar

2009-08-19T13:55:00Z

Yesterday’s high temperature in Eugene was just 1 degree shy of tying the record. This morning’s NAM high temperature for today is 102 and the GFS is 98. NWS has a high of 98. Yesterday, I thought the NAM would be really close to right and it was. It overshot the high by 1 degree, so I'm sticking with that trend today. I'm predicting a high of 101, which would set the new record.

Today will be the peak heat. Gradual (relative) cooling will follow, but it still looks warmer than seasonal averages and mostly sunny.

-KMTR Meteorologist Brent Prasnikar

Also interesting and timely considering the Lane County Fair is happening now... meaning of "Close, but no cigar"

http://www.phrases.org.uk/meanings/close-but-no-cigar.html

More Record Highs?

2009-08-18T16:12:00Z

As an encore to a couple new record highs in late July, Eugene will be close to the record high temperatures for August 18th and 19th. This morning, the NAM put highs at the exact temperatures that are the current records for Today and Wednesday. The GFS was a bit more conservative (as usual) and left highs at 95 degrees F and 96 degrees F. Either way, it's pretty hot. I just checked MOS data again and the GFS still likes 96 degrees F, but the NAM put the high at 102 degrees F. I hope you enjoy the heat while it’s here. Come November, when we get a freezing morning with fog, I'm sure many of you will be wishing we had this sun and heat again.

-KMTR Meteorologist Brent Prasnikar