Boy, am I glad that my job isn't dependent upon accuracy. Yes, I have a unique job where I can be wrong one day and still have a job the next. By no means does that translate into intentional sloppy forecasting though. I don't use the "stereotype" as an excuse. I want to be right! Who doesn't? Last month I recorded my temperature and condition accuracy for just Portland. A recap for the month of January, a near-perfect conditions report was marred by a couple bad days that dropped my temperature accuracy to near-fail percentages. Well, I am bound to make it up in order to gain your trust in me as a forecaster.
Last week, I tracked my temperature accuracy for the entire state of Oregon (plus a few Washington cities too). In the weather center here at Fox 12, we forecast for 35 cities in our "viewing area" each day. That includes cities as far North as Kelso/Longview, Washington, as far East as Baker City and as far South as Albany. Most of the North and Central Oregon Coast are also accounted for. Here are the results keeping the same temperature criteria as my monthly reports (+/- 3 degrees for accurate temperature):
Monday, February 13: 24/35= 68%
Tuesday, 14: 30/35= 85%
Wednesday, 15: 25/35= 71%
Thursday, 16: 33/35= 94%
Friday, 17: 28/35= 80%
The final average comes out to 79% for the week. Looking back at reports, my two worst days (Mon, Wed) both had LIGHT wind forecasts. Clearly I have an issue with forecasting temperatures when winds don't become a factor. I would have figured it to be the other way around. My best day was Thursday, when I missed just two locations (Baker City was off by 7 degrees, and Mt. Hood Meadows was off by 5).
Which cities was I most accurate? Both Astoria and Newport had spot on accurate temperatures two out of the five days. I also hit the high temperature for a handful of other cities throughout the week. The most inaccurate forecasts have a common theme. Sandy, Welches, Mt. Hood Meadows and Timberline Lodge each had three missed temperatures. Clearly I have an issue forecasting the Cascade range. That is evident in the breakdown of accuracy by region:
Oregon Coast- 95% accuracy
Willamette Valley- 84%
Portland Metro- 85%
Mt. Hood area- 50%
East of Cascades- 80%
Tough going in the Cascades. Temperatures vary greatly in a short area in the mountains which can make it difficult to accurately forecast temperatures. So I have an area I need to work on! But if you'd like a beach forecast, come talk to me!
Monday, February 20, 2012
Thursday, February 16, 2012
Tuesday's Quake
You may (or may not) have heard about the earthquake that occurred off the South Oregon coast this past Tuesday night. Not a lot of folks reported feeling it as it was situated roughly 160 miles west of Coos Bay. The 6.0 magnitude earthquake was unusually strong for an area that does have frequent tremors. So the fact that an earthquake occurred at this location is no reason to be alarmed. But was the strength of the quake something that coastal dwellers and Oregonians as a whole need to worry about? The short answer is: No.
Whenever an earthquake occurs under ocean waters, there is a period of time when we are on "pins and needles" awaiting word on if a Tsunami was generated or not. Luckily, no Tsunami was generated from Tuesday nights quake. The main reason was due to its location. The earthquake occurred along a fracture zone known as the Blanco Fracture Zone. This zone divides the very large Pacific Plate and the locally infamous Juan De Fuca Plate. The graphic below visually explains where the quake happened. The overall movement of the Pacific Plate is away from us. The Juan De Fuca Plate is shifting towards us. So when an earthquake occurs in the Blanco Fracture Zone, the overall movement of the Earth's plates is horizontal. This type of fracture zone is called a "Transform Boundary fault". The most famous of all fault lines in the United States is a transform boundary fault line, the San Andreas Fault. That fault is located in California and is the result of the Pacific Plate and North American Plate rubbing against each other.
Whenever an earthquake occurs under ocean waters, there is a period of time when we are on "pins and needles" awaiting word on if a Tsunami was generated or not. Luckily, no Tsunami was generated from Tuesday nights quake. The main reason was due to its location. The earthquake occurred along a fracture zone known as the Blanco Fracture Zone. This zone divides the very large Pacific Plate and the locally infamous Juan De Fuca Plate. The graphic below visually explains where the quake happened. The overall movement of the Pacific Plate is away from us. The Juan De Fuca Plate is shifting towards us. So when an earthquake occurs in the Blanco Fracture Zone, the overall movement of the Earth's plates is horizontal. This type of fracture zone is called a "Transform Boundary fault". The most famous of all fault lines in the United States is a transform boundary fault line, the San Andreas Fault. That fault is located in California and is the result of the Pacific Plate and North American Plate rubbing against each other.
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| Quake centered on the Blanco Fracture Zone |
The reason no Tsunami was generated from the Blanco quake is because the overall movement of the plates were horizontal, not vertical. Most Tsunami are created as a result of uplift from one plate moving under another. The displacement of water results in Tsunami. So as long as earthquakes occur in the Blanco zone, the Oregon coast should be spared from Tsunami.
The scientific community, in addition to the media, have been warning the population of the United States west coast that the "Big One" is imminent. Many are predicting a 9.0 magnitude quake will strike again, just as it did on January 26th, 1700. That quake occurred in a region known as the Cascadia Subduction Zone. Guess what? Oregon is a part of that zone. The Cascadia Subduction zone is an area where the Juan De Fuca Plate is literally sub-ducting, or folding underneath the North American Plate which we are anchored to. The 2011 Japan earthquake struck in a subduction zone where the Pacific Plate moves underneath the Okhotsk plate. As we all know, that resulted in a 9.0 earthquake and a deadly Tsunami that rushed over 6 miles inland and crossed the entire length of the Pacific Ocean!
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| The Cascadia Subduction Zone sits right off the Oregon coast |
Subduction zones are infamous for large quakes and Tsunami. Records from Japan that date back to1700 indicate that a Tsunami reached the eastern shores of Japan as a result of the 9.0 earthquake just off of our coast! The Cascadia Subduction Zone is the region that scientists are looking at for the next big quake. Oregon's coast has been outfitted with extensive Tsunami alert systems and warning signs but there is no way to prevent the Tsunami. Let's hope that this doesn't happen in our lifetime.
Friday, February 3, 2012
January Report Card
A former teacher of mine always offered this word of advice:
So, I begin my "resolution" to track and improve my forecasting skills this year. I haven't done this before, so I have no measuring stick to gauge improvement. But after completing 1/12th of the mission, there is definitely room for improvement and you will see why!
I will grade myself on two categories: accuracy of daily high temperatures and overall sky conditions/precipitation for that day. Out of the 31 days in January, I had a forecast for 21 of them. Each meteorologist and "consumer" of a weather forecast has their own definition of accuracy. I've always used the +/- 3 degree range in order to consider a forecast temperature accurate. As for the sky conditions/precipitation department, that is more subjective. If you'd like to judge my forecasts under your own parameters, well, you'll just have to wake up early and tune into the show each morning! So without further delay, here is the January Report.
January temperature accuracy (+/- 3 degrees of actual high temperature) was only 52%! 11 out of 21 days were accurately forecasted. Of the 11 correct high temperatures, only two of them hit the high temperature exactly! Not very impressive. I missed the high temperature by an average of 5.5 degrees (technically 2 degrees when you factor in the plus-minus). There was a run of six consecutive forecast days with a missed high temperature. Those days spanned the middle of the month (Jan. 18-26). Coincidentally, those six forecast days were right after the valley snowfall days. More on those snow days in a bit. So ultimately, my temperature forecasts have a lot of room for improvement. This January was somewhat challenging in regards to high temperature forecasting. We had several weather systems that would lead to strange high temperatures that would occur in the evening or overnight hours. I'm not making excuses, it's just something that adds a little difficulty to projecting an accurate temperature.
The Report does have a bright side though. The sky conditions and precipitation forecast was near perfect. 20 of 21 days had accurate conditions! That works out to 95%. The lone botched day was on the 23rd. I had called for some morning fog and a shower followed by some clearing during the afternoon hours. Turns out, it did not rain that day and we never really cleared out either. The day will go down as mostly cloudy. I also missed the high temperature that day. But that was it! Nailed the 20 other forecast days!
During the month, Portland saw some where near 5" of snow. It all fell in a four day period from the 15th through the 18th. I will list out my exact forecast thoughts for each day below:
Sunday, 15th: Trace-1" of snow at the lowest levels. Snow showers tapering off in the afternoon. High 40.
"If I get the forecast wrong, I want to go down on my forecast. Not someone else's."
It isn't a profound, thought-invoking quote but it always resonated with me. Best to own up to my own mistakes than say "it's not my fault". I do my best to follow the "station" forecast, or the show-to-show forecast. It's tough though when you have three or four different meteorologists forecasting and each have their own style!
I will grade myself on two categories: accuracy of daily high temperatures and overall sky conditions/precipitation for that day. Out of the 31 days in January, I had a forecast for 21 of them. Each meteorologist and "consumer" of a weather forecast has their own definition of accuracy. I've always used the +/- 3 degree range in order to consider a forecast temperature accurate. As for the sky conditions/precipitation department, that is more subjective. If you'd like to judge my forecasts under your own parameters, well, you'll just have to wake up early and tune into the show each morning! So without further delay, here is the January Report.
January temperature accuracy (+/- 3 degrees of actual high temperature) was only 52%! 11 out of 21 days were accurately forecasted. Of the 11 correct high temperatures, only two of them hit the high temperature exactly! Not very impressive. I missed the high temperature by an average of 5.5 degrees (technically 2 degrees when you factor in the plus-minus). There was a run of six consecutive forecast days with a missed high temperature. Those days spanned the middle of the month (Jan. 18-26). Coincidentally, those six forecast days were right after the valley snowfall days. More on those snow days in a bit. So ultimately, my temperature forecasts have a lot of room for improvement. This January was somewhat challenging in regards to high temperature forecasting. We had several weather systems that would lead to strange high temperatures that would occur in the evening or overnight hours. I'm not making excuses, it's just something that adds a little difficulty to projecting an accurate temperature.
The Report does have a bright side though. The sky conditions and precipitation forecast was near perfect. 20 of 21 days had accurate conditions! That works out to 95%. The lone botched day was on the 23rd. I had called for some morning fog and a shower followed by some clearing during the afternoon hours. Turns out, it did not rain that day and we never really cleared out either. The day will go down as mostly cloudy. I also missed the high temperature that day. But that was it! Nailed the 20 other forecast days!
During the month, Portland saw some where near 5" of snow. It all fell in a four day period from the 15th through the 18th. I will list out my exact forecast thoughts for each day below:
Sunday, 15th: Trace-1" of snow at the lowest levels. Snow showers tapering off in the afternoon. High 40.
We officially picked up a Trace of snow in Portland and the high temperature was 38 degrees.
Monday, 16th: Mainly dry morning with some snow showers in the afternoon. High 39.
Officially saw 0.08" snow during the afternoon. The high temperature was 38 degrees.
Tuesday, 17th: Rain/snow mix at times, sticking at about 1,000 feet. A south wind helps warm us. High 40.
We saw a rain/snow mix (I think it was more snow than rain) and that South wind (10-20) warmed us up to exactly 40 degrees!
Wednesday, 18th: Rain/snow turns to all rain by 7am in most metro area. A high of 48.
Snow only fell in the early morning hours, the rain began by 7am and lasted all day! The high was 53.
So the accuracy of my forecasts during this winter weather period was a pleasant surprise. Forecasting snow in Portland can be very challenging. The Report overall was interesting to see. There is plenty of room for improvement in the temperature area obviously. Conditions are my strength and I expect to see that continue. I hope the Report doesn't sway your opinion of where you get your forecast. But check back each month to see if and how I improve as the year continues!
Tuesday, January 24, 2012
Media and Weather
The first deadly severe weather outbreak of 2012 occurred Sunday overnight into Monday in parts of Arkansas, Tennessee and the Gulf Coast states, an area known as "Dixie Alley". Already hearing reports of multiple EF-3 tornadoes and that total may increase as field analysis will be conducted over the next few days.
Whenever Mother Nature strikes, the media is sure to follow. Last night, ABC's national news began their coverage with this lead-in:
Video courtesy of Alabamawx.com
The lead-in is absolutely misleading. The wording of the script gives the illusion that forecasters in the region failed the public. In NO way was this mini-outbreak a "surprise" event. I was aware of this event days before just by following social media posts of meteorologists who work in the area. Folks in the Midwest and South should naturally pay more attention to forecasts and warnings issued by their meteorologists. And for several days, this event was projected to happen. Look at this blog post by one of the top meteorologists in the Alabama, James Spann. Citizens in the impacted areas had at least 24 hours notice that a dangerous weather event could occur and areas under Tornado Warnings had at least 20 minuets of lead time, according to Spann.
Most people are aware of "Tornado Alley" where the highest concentration of tornadoes occur anywhere on Earth. What most people do not know is that there is a second "alley", known as "Dixie Alley" (Arkansas, Tennessee, Louisiana, Mississippi, Alabama and Georgia) that is just as dangerous. Within this region, a secondary tornado season exists during the winter months! Take a look at these graphs that compare Tornado to Dixie Alley:
Notice the spike of strong and deadly tornadoes in the winter months that occur in Dixie Alley as compared to the Plains (or Tornado Alley). A drastic difference. To compound the danger that Dixie Alley presents, take a look at this graph:
Late afternoon-evening-overnight storms add to the danger of Dixie Alley outbreaks. These tornadoes often strike while people are on their way home from work or sleeping. It's tough to follow storm coverage when your asleep. This is why Spann often promotes weather radios that allow emergency broadcasts to be issued when danger is on the way. A great tool to keep people safe when not near a television.
Tornadoes do not spawn randomly. A meteorologist that is worth his or her weight in gold can forecast the threat for tornadoes a few days in advance using weather maps. It is nearly impossible to forecast the exact track of a specific twister, however. But with ample warning time, it shouldn't matter.
Current and accurate weather information is important in any extreme weather situation, regardless of location. James Spann has perfected the art of T.V. meteorology with his policy of wall-to-wall weather coverage if ANY county within his stations' viewing area is under a severe weather warning (sorry, Judge Judy fans!). With coverage that extensive, there should be no excuse for saying these tornadoes struck "without warning"! So why does the media come out and state exactly that? Was it because people died? Or are certain media outlets just that lazy and decide to spin their own story out of what happened?
Whenever Mother Nature strikes, the media is sure to follow. Last night, ABC's national news began their coverage with this lead-in:
Video courtesy of Alabamawx.com
The lead-in is absolutely misleading. The wording of the script gives the illusion that forecasters in the region failed the public. In NO way was this mini-outbreak a "surprise" event. I was aware of this event days before just by following social media posts of meteorologists who work in the area. Folks in the Midwest and South should naturally pay more attention to forecasts and warnings issued by their meteorologists. And for several days, this event was projected to happen. Look at this blog post by one of the top meteorologists in the Alabama, James Spann. Citizens in the impacted areas had at least 24 hours notice that a dangerous weather event could occur and areas under Tornado Warnings had at least 20 minuets of lead time, according to Spann.
Most people are aware of "Tornado Alley" where the highest concentration of tornadoes occur anywhere on Earth. What most people do not know is that there is a second "alley", known as "Dixie Alley" (Arkansas, Tennessee, Louisiana, Mississippi, Alabama and Georgia) that is just as dangerous. Within this region, a secondary tornado season exists during the winter months! Take a look at these graphs that compare Tornado to Dixie Alley:
Tornadoes do not spawn randomly. A meteorologist that is worth his or her weight in gold can forecast the threat for tornadoes a few days in advance using weather maps. It is nearly impossible to forecast the exact track of a specific twister, however. But with ample warning time, it shouldn't matter.
Current and accurate weather information is important in any extreme weather situation, regardless of location. James Spann has perfected the art of T.V. meteorology with his policy of wall-to-wall weather coverage if ANY county within his stations' viewing area is under a severe weather warning (sorry, Judge Judy fans!). With coverage that extensive, there should be no excuse for saying these tornadoes struck "without warning"! So why does the media come out and state exactly that? Was it because people died? Or are certain media outlets just that lazy and decide to spin their own story out of what happened?
I've found in my time working in television that weather is often disregarded when it comes to accurately reporting on events. I have heard many stories on various news channels that incorrectly mention current or past weather conditions and events. Weather here in the Pacific Northwest is not as extreme as the weather in other parts of the country. We are not familiar with the severe weather that the Plains and Gulf Coast South deal with on a seasonal basis. That is something I plan to fix!
I have worked with people who are familiar with weather and who REALLY do care about the accuracy of the story they are writing or giving. But there are times when I have to shake my head when I listen to an inaccurate report I often encourage my co-workers to talk with me about current weather conditions if they are unsure of what to put in scripts or say on air when talking about a weather story. It is important to relay proper information to the public when it comes to watches and warnings. Not only from a meteorology standpoint as it could save lives, but also from a journalistic view as well.
There are reports that meteorologist James Spann will be interviewed by ABC regarding the aftermath of the tornadoes. Hopefully he will set the record straight on national television, much unlike Diane Sawyer the night before.
Tuesday, January 10, 2012
Bowl Wrap-Up
Last night's snozzzzzzer capped the 2011-12 College Football post season. Over the span of nearly three weeks, teams seized the opportunity to close the season on a high note while others squandered their chance, some seemed to even give it away. Various teams showed up to play, others sleep-walked through 60 minuets of football. In my mind, this was the most entertaining bowl season in recent memory. Typically, the early bowl games can be duds. That was not the case this season, as some of the early games were among the best of the bunch. I'll recap my picks first, then give out some highly coveted awards...I see you moving to the edge of your seat.
My record for the 2011-12 Bowl Season finished at..... 25-10! Thank you! Thank you! Much improved over last seasons 20-15 record. What can I say? The games just seemed easier to pick. I actually took part in a cash pool that required selecting winners based on point spreads and over/under total points. I won that pool, and finished with a record of 24-11 in that pool. I never referenced my blog pick when choosing winners for the pool, the near-similar records were just coincidence.
Let's breakdown the gauntlet of games:
Most Exciting Game: This is a tough decision, so many good contenders. A great finish to the SDSU/Louisiana-Lafayette New Orleans Bowl which was decided by a last-second field goal. Toldeo-Air Force Military Bowl was a doozie, Air Force failed to score on a two-point conversion and lost by just one point in a high scoring affair. Utah mounted a ferocious comeback to beat Georgia Tech in overtime at the Sun Bowl. Michigan State and Georgia both proved there was no hangover from losing their conference championship games as it took 3 overtimes to settle the Outback Bowl. The Rose Bowl was an action-packed, high-scoring, record-breaking affair. Only to be followed by the Fiesta Bowl in which Oklahoma State and Stanford traded blows before the Cardinal's kicking game blew it. If you think points are exciting, then these last two games made you one happy sports fan! West Virginia racked up a all-time bowl record 70 points in their rout of Clemson. But hands down the most exciting game of the season was Baylor and Washington as the defenses basically stepped out of the way of each offense and let a track meet break out on a football field. 123 combined points, 1,397 combined total yards made the Alamo Bowl the most exciting bowl game of this season!
Most Boring Game: This is a tough one because the early bowls typically take this category but this year the early games were unusually entertaining. The BBVA Compass Bowl qualifies, as the game was all but over after three 1st quarter touchdowns by SMU. Oklahoma steamrolled Iowa in the Insight Bowl that really wasn't all that competitive. I'm trying not to let a bias get involved here, but the National Championship game was pretty dull. 21 total points, all scored by Alabama. But only one touchdown. It was another "field goal-palooza" of all intents and purposes. LSU didn't really play like they wanted to win. 92 total yards on offense? Georgia Southern put up more yards on Alabama than LSU did! I understand Alabama has a beast defense, but it isn't IMPOSSIBLE to score on them. And for the National Championship Game being a shut-out, congrats, you are the most boring game of the bowl season!
Best Bowl Win: I think West Virginia's win in the Orange Bowl was as big as it gets. Not only on the field, but off it too. The Mountaineers sent a statement to Clemson and to the Big East Conference by putting up 70 points in a dominant BCS performance. West Virginia is headed to the Big 12 Conference next season (at least THEY think so), and destroying their ACC opponent while headed out the pathetic Big East door give them a ton of credit and momentum heading into next season. Look out for the Mountaineers next season.
Worst Bowl Loss: Washington surrendered 777 yards of offense, including 482 of those rushing. Hands down the worst performance of this bowl season. It cost the Huskies Defensive coordinator his job.
Most Ironic Loser: Air Force in the Military Bowl
Most Deserving Winner: Florida Gators in the Gator Bowl
Dumbest Moment: Towards the end of the third quarter in the Capital One Bowl, star wide receiver Alshon Jeffery threw a punch at a Nebraska defender. Both players were ejected. At the end of the game, Jeffery was named Player of the Game. How can you give an award to a player who was KICKED OUT of the game! Doesn't matter that he caught a Hail Mary pass at the end of the 1st half for a touchdown.
The 2011-12 College football season was a great one! A lot of late-season drama spilled over into the bowl season. Can't wait for next year! As usual, too early to look ahead. Well, not really but I won't get into that.
My record for the 2011-12 Bowl Season finished at..... 25-10! Thank you! Thank you! Much improved over last seasons 20-15 record. What can I say? The games just seemed easier to pick. I actually took part in a cash pool that required selecting winners based on point spreads and over/under total points. I won that pool, and finished with a record of 24-11 in that pool. I never referenced my blog pick when choosing winners for the pool, the near-similar records were just coincidence.
Let's breakdown the gauntlet of games:
Most Exciting Game: This is a tough decision, so many good contenders. A great finish to the SDSU/Louisiana-Lafayette New Orleans Bowl which was decided by a last-second field goal. Toldeo-Air Force Military Bowl was a doozie, Air Force failed to score on a two-point conversion and lost by just one point in a high scoring affair. Utah mounted a ferocious comeback to beat Georgia Tech in overtime at the Sun Bowl. Michigan State and Georgia both proved there was no hangover from losing their conference championship games as it took 3 overtimes to settle the Outback Bowl. The Rose Bowl was an action-packed, high-scoring, record-breaking affair. Only to be followed by the Fiesta Bowl in which Oklahoma State and Stanford traded blows before the Cardinal's kicking game blew it. If you think points are exciting, then these last two games made you one happy sports fan! West Virginia racked up a all-time bowl record 70 points in their rout of Clemson. But hands down the most exciting game of the season was Baylor and Washington as the defenses basically stepped out of the way of each offense and let a track meet break out on a football field. 123 combined points, 1,397 combined total yards made the Alamo Bowl the most exciting bowl game of this season!
Most Boring Game: This is a tough one because the early bowls typically take this category but this year the early games were unusually entertaining. The BBVA Compass Bowl qualifies, as the game was all but over after three 1st quarter touchdowns by SMU. Oklahoma steamrolled Iowa in the Insight Bowl that really wasn't all that competitive. I'm trying not to let a bias get involved here, but the National Championship game was pretty dull. 21 total points, all scored by Alabama. But only one touchdown. It was another "field goal-palooza" of all intents and purposes. LSU didn't really play like they wanted to win. 92 total yards on offense? Georgia Southern put up more yards on Alabama than LSU did! I understand Alabama has a beast defense, but it isn't IMPOSSIBLE to score on them. And for the National Championship Game being a shut-out, congrats, you are the most boring game of the bowl season!
Best Bowl Win: I think West Virginia's win in the Orange Bowl was as big as it gets. Not only on the field, but off it too. The Mountaineers sent a statement to Clemson and to the Big East Conference by putting up 70 points in a dominant BCS performance. West Virginia is headed to the Big 12 Conference next season (at least THEY think so), and destroying their ACC opponent while headed out the pathetic Big East door give them a ton of credit and momentum heading into next season. Look out for the Mountaineers next season.
Worst Bowl Loss: Washington surrendered 777 yards of offense, including 482 of those rushing. Hands down the worst performance of this bowl season. It cost the Huskies Defensive coordinator his job.
Most Ironic Loser: Air Force in the Military Bowl
Most Deserving Winner: Florida Gators in the Gator Bowl
Dumbest Moment: Towards the end of the third quarter in the Capital One Bowl, star wide receiver Alshon Jeffery threw a punch at a Nebraska defender. Both players were ejected. At the end of the game, Jeffery was named Player of the Game. How can you give an award to a player who was KICKED OUT of the game! Doesn't matter that he caught a Hail Mary pass at the end of the 1st half for a touchdown.
The 2011-12 College football season was a great one! A lot of late-season drama spilled over into the bowl season. Can't wait for next year! As usual, too early to look ahead. Well, not really but I won't get into that.
Monday, January 9, 2012
Any Hope For Snow?
I posted last month about the possibilities of snow on Christmas. The holidays came and went, no snow. No "typical" winter weather to speak of at all. Just dull weather. A shower here and there. Fog most mornings and some decent stretches of sunshine. Will we transition into a more La Nina weather pattern which would yield a better possibility of snow? According to this morning's model run, it does not look good.
One of the four daily model runs occurs while I'm at work each morning. The 06z model runs are notorious for being "outliers" in comparison to their 00z and 12z counterparts. By the way, we use the postmark "Z" to denote "Zulu time". It is basically Greenwhich Mean Time, so 00z model run translates to 12 midnight in England. So, when this mornings 06z 850mb comparisons came out, it did not spark hope for a return to winter weather.
This is the GFS model run, just one of several separate models that Mets use to forecast. Within the GFS model, several different "perturbations" are played out. The graph above shows the 850mb temperature plotted out with each run. The 850mb temperature gives us temps at about 5,000ft elevation. We can use the 850mb temps to translate a surface temperature. Ideally, we like to see 850mb temperatures of at least -6 degrees Celsius in order to get excited about any possibility of snow in our area. The 06z run doesn't inspire hope. The green line is climatology, what we should expect. The red line is the average of all the models and the blue line represents the "operational" run, the actual model that we see each day. Just a week ago, the ensemble mean had temperatures down near -3 to -5 degrees Celsius, and I recall a few operational runs that dipped into -10 degrees Celsius last week as well. But that's life in the world of a weather forecaster. You get excited about a big arctic outbreak and 6 hours later...that model takes it away from you. I can almost guarantee that by the time I post this, the 12z model run will be drastically different!
I can tell you that this morning's 06z GFS 850mb map does not show much of anything below 0 degrees for the next 384 hours! The 7 day forecast looks nice, however. By mid-week, gusty east winds will help keep us clear of clouds and fog each morning. With the clear conditions, nights will be chilly. Lows may touch the mid 20's. Remember, peak snow season for Portland is right around the corner, so things can change in an instant!
One of the four daily model runs occurs while I'm at work each morning. The 06z model runs are notorious for being "outliers" in comparison to their 00z and 12z counterparts. By the way, we use the postmark "Z" to denote "Zulu time". It is basically Greenwhich Mean Time, so 00z model run translates to 12 midnight in England. So, when this mornings 06z 850mb comparisons came out, it did not spark hope for a return to winter weather.
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| 850mb Temperatures look boring |
I can tell you that this morning's 06z GFS 850mb map does not show much of anything below 0 degrees for the next 384 hours! The 7 day forecast looks nice, however. By mid-week, gusty east winds will help keep us clear of clouds and fog each morning. With the clear conditions, nights will be chilly. Lows may touch the mid 20's. Remember, peak snow season for Portland is right around the corner, so things can change in an instant!
Tuesday, December 20, 2011
Snow on Christmas?
We are only 6 days away from Christmas! The big question each time December 25th rolls around is whether or not we will be seeing a white Christmas. Living in Northwest Oregon, we already have a handicap getting snow down to the valley floor. The Pacific Ocean is too close and acts as a moderating influence to our weather. It just keeps temperatures too warm for a persistent snow threat.
Portland's coldest month is January, where the mean average temperature is 39.9 degrees. That is "comfortably" above the freezing mark, making it tough for snow to fall. Let's look over the Cascades at Redmond's coldest month, that's December. The average mean temperature is 32.7 degrees. So why the difference between Portland and Redmond? Elevation plays a key role. Portland sits at roughly 200 feet above sea level. Redmond is at nearly 3,000 feet in elevation. The thermodynamic state of the atmosphere cools as you gain elevation. So you'd expect Redmond to be colder than Portland. Another issue is "continentality". The land heats and cools much faster than the ocean, so the closer to a body of water you are, the more temperate the climate may be. That is exactly what we deal with here in Portland. We are just close enough to the Pacific Ocean to be impacted by its moderating factors.
So let's answer the question: what is the possibility of a white Christmas in Portland? You actually have a better chance of seeing snow on Christmas if you live in Downtown Portland rather than out near the Portland International Airport. On average, Downtown Portland has a 4% chance of seeing a white Christmas. And at PDX? If you had a worse chance, it'd be no chance... only a 1% chance of seeing the white stuff near the airport. Portland's most recent "white Christmas" was back in 2008, where close to 1" fell on the 25th to go along with the nearly 10" that was already on the ground (as a side note, December 2008 saw 19" of snow!). What about Redmond's chances? Since 1949, Redmond has had 12 white Christmases and on average has a 24% chance of seeing snow on the 25th.
Just for fun, Portland's snowiest day is January 19th where since 1884 it has snowed 15 times and on average there is a 12% chance for snow that day.
What does this Christmas have in store? This December has been very dry. The airport has reported only a tenth of an inch of rain through the 19th. That is nearly 3.39 inches below normal. The driest December on record was in 1976 where only 1.38 inches fell. So we are well on our way setting a new record. We remain locked in this very dry weather pattern. All month long, high pressure has been planted out over the Pacific Ocean, leaving us dry. The weather maps continue to hint at this high pressure staying more or less in place.
The high pressure clearly shows up on Christmas Eve morning. The ridging sends any rain up over the top of us and keeps us dry and mainly sunny for the 24th. However, a weakness disrupts our nice weather by Christmas morning. That weakness will bring us some showers by the time you are opening presents. But temperatures just won't be cold enough to produce snow. Christmas average temperature in Portland is 45 degrees, I am aiming for 43. So no white Christmas this year!
Portland's coldest month is January, where the mean average temperature is 39.9 degrees. That is "comfortably" above the freezing mark, making it tough for snow to fall. Let's look over the Cascades at Redmond's coldest month, that's December. The average mean temperature is 32.7 degrees. So why the difference between Portland and Redmond? Elevation plays a key role. Portland sits at roughly 200 feet above sea level. Redmond is at nearly 3,000 feet in elevation. The thermodynamic state of the atmosphere cools as you gain elevation. So you'd expect Redmond to be colder than Portland. Another issue is "continentality". The land heats and cools much faster than the ocean, so the closer to a body of water you are, the more temperate the climate may be. That is exactly what we deal with here in Portland. We are just close enough to the Pacific Ocean to be impacted by its moderating factors.
So let's answer the question: what is the possibility of a white Christmas in Portland? You actually have a better chance of seeing snow on Christmas if you live in Downtown Portland rather than out near the Portland International Airport. On average, Downtown Portland has a 4% chance of seeing a white Christmas. And at PDX? If you had a worse chance, it'd be no chance... only a 1% chance of seeing the white stuff near the airport. Portland's most recent "white Christmas" was back in 2008, where close to 1" fell on the 25th to go along with the nearly 10" that was already on the ground (as a side note, December 2008 saw 19" of snow!). What about Redmond's chances? Since 1949, Redmond has had 12 white Christmases and on average has a 24% chance of seeing snow on the 25th.
Just for fun, Portland's snowiest day is January 19th where since 1884 it has snowed 15 times and on average there is a 12% chance for snow that day.
What does this Christmas have in store? This December has been very dry. The airport has reported only a tenth of an inch of rain through the 19th. That is nearly 3.39 inches below normal. The driest December on record was in 1976 where only 1.38 inches fell. So we are well on our way setting a new record. We remain locked in this very dry weather pattern. All month long, high pressure has been planted out over the Pacific Ocean, leaving us dry. The weather maps continue to hint at this high pressure staying more or less in place.
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| Christmas Eve Morning |
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| Christmas Morning |
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| Rain by Presents Time |
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