Les's Winter Weather Outlook 2009-2010

Les’s Winter Weather Outlook 2009-2010

It’s that time of year again! It is fall and winter is right around the corner. The following post is going to contain my thoughts as to what I expect across the region for the November – March period 2009-2010. I will be discussing many things such as our current pattern and the factors leading up to our winter time pattern. I will be showing graphics depicting factors such as El Nino, temp and precip trends, snow cover, the on going solar minimum and much, much more!

Fall 2009 – The Current Pattern and Trends

I always begin every Winter Outlook looking at our current weather pattern as that can sometimes give us clues as to what the upcoming winter will bring. We have basically been stuck in a relatively cool and stormy pattern over the Midwest since last winter. The maps below will clearly show the temp. and precip. departures over the country for the past 30 days.

Temps:

Precip:



You can clearly see that the mean trough has been positioned over the Plains. The temp. trends reflect this quite nicely. The precip. trends also tell us where the storm track has been. Drier conditions have existed over the SW CONUS as well as along the East Coast. We have been seeing a ridge over the SW, a trough over the Plains and Midwest and another ridge over the East Coast.

Soil moisture is also a very important clue. Again, look at the soil moisture map below and you can see the areas that have been very wet.

For the upcoming winter, I expect the mean trough position to continue to be right where we have seen it for Nov, and then late in the month or in early Dec., I expect the mean trough and storm track to shift east, putting the Ohio Valley in a favorable area for snowfall. As we roll on thru winter by mid to late Jan and Feb, the storm track should shift to the Eastern Apps / East Coast regions. See map below.

El Nino

El Nino has been the talk of town this year. The El Nino has been weak for the most part but the Pacific waters have warmed considerably over the past month due to a Westerly Wind Burst (WWB) and enhanced MJO activity. I expect one more of these WWB’s to come in during the month of November. Weak El Nino conditions favor cold weather over the Eastern US for winter versus moderate or strong events. The map below is a composite of temp departures of all Weak El Nino winters since 1950.

However, due to the recent warming, I expect El Nino to reach moderate status before weakening by about December. Below is a loop of the sea surface temps. departures from Feb 2009 thru October 2009. As you can see, we began with a La Nina and we have transitioned into an El Nino now.

The ENSO models for October fit my thoughts very well with a moderate peak in December and then it weakens for the second half of the winter. When we peak and fall in regards to this El Nino will have an impact on how much cold and snow we get here.

Currently, I do not expect a dry and mild winter. Those are the typical impacts from a Strong El Nino and we clearly are not going to see this occur. We should see just the opposite. I have more evidence supporting a colder outlook and a stormier one as well.


QBO

A negative QBO does support more high latitude blocking in the Northern Hemisphere. The QBO has been in the negative teens for the past few months and I expect that to remain that way for the winter. This could help assist us in getting a West Coast / NW Canada Ridge going which in return allows a Trough to develop over the East.

NAO

The NAO when in a negative phase also promotes stormy conditions and colder conditions for us as well. I expect the NAO to be ever changing. The NAO has been negative for a good chunk of October and we have been very cold and stormy so far. We have seen a few milder says as of late because the NAO has risen. As the state of the NAO changes phases, big storms can often develop. I expect a very stormy winter and this is one of the reasons why. If the NAO stays around neutral or slightly negative, then the storm track should favor us /vs./ having a Lakes Cutter system or an East Coast system.

PNA

The PNA when positive supports a ridge out West and a trough over the East. Like the NAO, I expect this phase to change throughout the winter season. Due to a moderate El Nino, a strong Pacific Jet I do not believe will allow the Western Ridge to stay intact for very long. We will see cold air outbreaks at times, especially during the second half of the winter as El Nino weakens, the NAO tanks, and the PNA should go mainly positive. This should allow for a pretty cold pattern for Jan and Feb. For the first half of winter though, the Pacific Jet should stay strong and a –PNA pattern should be the end result. This does not mean that we’ll blow torch at all, but it does ensure an extremely stormy pattern will occur for the region. If the storm track is correct, then we get nailed with heavy wintry precip.


Snow Cover

The current snow cover has been expanding rapidly over Arctic Canada and the sea ice has been building pretty good as well. The graphic below shows this.

Now, how are we doing relative to avg for this time of year?

As you can see, we’re not doing too bad at all. This is about right where we should be minus Western Canada. But, warm and dry conditions have occurred there so this is why that area has been below avg in snow cover. Current computer models though do suggest that the cold and snow will continue to build even in Western Canada in the upcoming weeks. We should have a nice supply of cold air for storm systems to tap into.


PDO

We are in a cold phase of the PDO. A +PDO combined with a Weak El Nino usually produces some of the coldest winters on record for the Eastern US. The PDO has been rising towards neutral over the past 2 months and the index value was actually weakly positive for Sept. For the upcoming winter though, I do expect it to cool once again and remain near Neutral or weakly negative. If we do see a –PDO and a –NAO though, check out the results.

The nation as a whole is pretty cool.


Solar Minimum

We are in the midst of a multiyear solar minimum. We have not seen the sun this quiet in our lifetimes. This is a big factor why I do not expect the strength of the Pacific Jet and El Nino to blow torch our temps. this winter. The sun has produced no sunspots 79% of the time so far in 2009 (per spaceweather.com). The oceans are cooling and so is the globe. Record snows have been occurring in other parts of the World already this year and I expect portions of Canada and the US also to be setting records for cold and snow. Someone is going to get pounded this winter but as always, the question is who?


Where Does the Ohio Valley Stack Up?

As you can see, I have presented a lot of data that points to a cold and snowy winter for us. But, I have also presented a few things that do not. The good far outweighs the bad though. Below, I will present a monthly break down as to how I see things going for us.

Nov – I see a continuation of the current pattern for at least the first half of the month. The mean trough position remains to our NW. We’ll see a lot of Lakes Cutter storms. The snow cover should build though quite nicely to our NW in places such as the Rockies, the Dakotas, Nebraska, Kansas, and the Upper Midwest. This is good news as storm systems will be able to tap into the cold air more easily down the road. By mid to late month, I expect the mean trough to begin to shift East. I expect our first accumulating snow to occur in late Nov.

Dec – As the storm track begins to shift to the East, I expect Dec to be a good month for snow. Due to the factors I have mentioned above, the strong Pacific Jet will keep the storminess going. I expect the SE Ridge to come into play, however, it should be positioned further to the East and be much flatter to produce more inland runner systems. I expect to see a couple of storms track to our SE up the Apps. to give us a pretty snowy month relative to average. Due to the strong Pacific Jet though, we can see a couple of milder periods also as the pattern reloads.

Jan and Feb – I expect Jan to start off the same as Dec. By mid to late month though I expect conditions to turn very cold. The storm track should be along the Eastern side of the Apps. transitioning to East Coast Lows by late Jan and Feb. For us, cold air will be the bigger story, but we should see numerous Clipper systems reinforcing the cold air over our region. The tracks of these clipper systems should be favorable for the Ohio Valley, especially the Southern OH Valley to get in on the action. I expect El Nino to be weakening and the NAO moving into more of a negative state. As El Nino continues to weaken and the NAO continues to tank in Feb., the mean storm track should be East of us, and we may miss out on some of the bigger snow events, however, Clipper systems will keep our snow appetite satisfied and the cold air should keep it on the ground for a while also. Temps should avg well below avg for these 2 months and a few mornings below zero are not entirely out of the question.

Mar – I think one decent snow event is possible during the first week or so of the month before we begin to see some miler days during the second half of the month. This month is so far out in time, that I really don’t have a lot of thoughts at this point as to how winter will finish.


In conclusion, winter temps. as a whole should end up below avg for the period as a whole. Snowfall should be above avg. Due to the mean trough being out to our West as winter begins, and slowly getting more favorable for us by Dec and early Jan, I expect the highest snowfall totals to be to the NW of the Tri-State. For CVG, we should do very well also. Below, you will see my snowfall map for the Ohio Valley.

If you have any questions, just ask. Please feel free to agree or disagree as well. Thanks for reading!

Forecast Ohio Valley Video

Major Snow and Ice Event - Jan 26-28, 2009

Good evening folks!

A major snow and ice event will affect the OH Valley starting Mon night and continuing thru Wednesday. Heavy amounts of snow and ice are likely for the region. Click on the video below to watch it, and sit back, relax, and enjoy the show!

Twin Clippers to Affect the Region Next Week

1/10/09 10pm

Tonight's video is going to be way differnet then what you're typically used to viewing. We have two clipper that will affect the region next week, followed by BITTER COLD! I hope you enjoy the music.

A Wintry Pattern Developing...

12/30/08 10pm

Good evening Folks! Please check out the video below. My thoughts include: The Jan 6-7th winter storm threat, future snow threats, and also how long will the cold pattern last?

Winter Storm Likely for Mon Night thru Wed. Morning

Here are my thoughts on the upcoming winter storm:

Les's Winter Weather Outlook 2008-2009

Les's Winter Weather Outlook 2008-2009

You’ve asked…. You’ve waited…. And now it’s here! Sit back, relax, and I hope you enjoy reading this Outlook. As most of you know, I have been researching what our upcoming winter may hold in store for us since July! This year’s Winter Outlook for the region will consist of what I think will happen from November 2008 through March of 2009.

October – The Month of Clues

October is a very important month of the year. A lot of clues as to what could happen during the upcoming winter are found during this month. You just have to look, and know what you’re looking for. So, I’ll start off this section of the Outlook revealing the clues and what they potentially could mean for us down the road.

ENSO State

The ENSO state of last winter was a Strong La Nina. We had a very strong Pacific Jet which brought us numerous storms throughout the winter season. We had a wide range of temps. as well. That is typical of a strong La Nina. Thus, predicting what would happen last winter was actually fairly easy. This year, however, is going to be much more difficult. One of the reasons why, is that the Pacific is not going to dominate the pattern. The Atlantic will have a much more important say in how things go. We’ll get to that in the NAO section in a little while. Currently, we are seeing ENSO Neutral conditions, meaning that the sea surface temps. in the Equatorial Pacific are neither cooler nor warmer then normal. In regards to this years ENSO state, I am expecting us to be in a Weak La Nina. There are many factors that are pointing to this.

First, let’s start off with what the models are saying. Below, you will see the latest run of the climate models and their predictions for what ENSO will do. As you can see by the graphic, the models are clustered around a weak La Nina status.



Now, let’s see what the Sea Surface Temps. (SST’s) are doing in the Equatorial Pacific. Below, you will see an animation of the SST’s for the past 6 months.



We have been in ENSO Neutral conditions for a while now, but look at how the SST’s drop on the last few frames. Whether my ENSO call is right or wrong, it really doesn’t matter. The atmosphere is still acting like we are in a La Nina anyways.

PDO – In a Strong Negative State


Another factor pointing to a weak La Nina is the phase of the PDO. When the PDO is in a cold or negative state, we typically see more La Nina’s then we do El Nino’s. Thus far, 2008 ranks as #5 in the strongest negative PDO states since records on this were kept beginning in 1950 for the Jan. through Sept. period.



When looking back at snowfall data in the classic winters of the 60s and 70s, one of the factors was that we saw more La Nina’s and the PDO was in a negative state.

QBO

The QBO, which has been running strongly positive, is now trending back towards negative, although very slowly. The current QBO index value for Sept was 11.62. I expect that we should see weakly positive or even neutral by early 2009. This is more good news for those of you wanting a colder and snowier winter then avg.

NAO

As most of you know who follow the weather a lot or have read my outlooks in the past, you know that the NAO in a negative state favors colder and stormier weather for the Eastern US. However, this has a bigger impact on the East Coast then it does for us. The NAO has been primarily negative for most of this year, minus September and October. This is a GOOD THING though. There is a lot of data out there that I have read, which suggests that 80% of the time, when the NAO averages out to be positive in Oct, then it’ll be negative for the winter. For those classic winter storm tracks to ride up the Appalachian Mountains, we want the NAO to be weakly negative or neutral. In my opinion, if the NAO is too negative, then the storm will track up the East Coast, as the high around Greenland would steer the low pressure tracking in that fashion. Thus, we are cold and dry and miss out. If the NAO is too positive, then the blocking high is too far west, and we get a system that tracks well to our West and we are either warm and dry, or get rain out of it. For this winter, I expect the NAO to be positive at times and strongly negative at other times. So, when you average it all out, it should average weakly negative or pretty close to neutral. This is pretty good in terms of snowfall and cold air potential for us here in the Ohio Valley.

PNA and EPO

La Nina’s and negative PDO’s tend to favor the PNA being in a negative state. This is not good news for us, in terms of getting sustained cold and snow. However, this go around, I do not believe this to be true. I think the opposite will happen. A cold pool of air is building in the Northern Pacific (-PDO) So, that favors a trough up there. Downstream, you have to have a ridge, correct? Yes. So, that would place a ridge near the West Coast. Then, you have to have a downstream trough, correct? Yes. That would place the trough over the Central and Eastern US. Another factor in getting the arctic air down into the Eastern US is for the EPO to be negative. For a while now, it has been running positive. That is one factor in why we have had a warm Aug and Sept. However, there are signs that the EPO is going negative. So, there are more good signs if you like the cold air for the upcoming winter season.

Solar Minimum

The solar activity, or lack thereof, has been a huge weather story for 2008. I don’t have a lot of time to go into much detail here, but for further information, I suggest going to http://www.spaceweather.com to get the latest information on the sun spot activity. To sum up what I have been noticing is this… Records on the suns activity have been kept by NASA since the 1960s. So far in 2008, we have seen very low sun spot activity. The solar winds have dropped by 30%. What this means is, we have been seeing less energy being put out from the sun. The arctic air masses that are building in Alaska and Northern Canada are going to be able to build earlier then usual as well as be colder then usual. Nothing is more evident then looking at Alaska’s weather. I have seen record breaking cold occurring for Oct already! Lows around 20 below zero have been occurring up there for the past week. Fairbanks has had a very chilly October thus far as well. It has been the coldest Oct. so far in the last 15 or 20 years!

Arctic Sea Ice and Snow Cover

As I have talked about before, the faster the snow cover and arctic sea ice can form, the colder the air masses will be when they build up in Alaska and Canada. We are already seeing this take place. Here is the current arctic sea ice and snow cover picture:



How are we doing compared to what we typically see this time of year?



We are a little behind in the snow cover dept. but we will see more and more positive anomalies over the next month, so we are looking good there. Arctic Sea Ice production has increased and continues to increase at a rapid rate! This is wonderful news here!

What is the CFS Climate Model Saying?

The CFS Climate Model predicts a cold, Nov – Jan period.



Putting it All Together – What Does This Mean for the Ohio Valley?

So, now that I have some of you confused, what does all this mean for the OH Valley? I expect this winter to be in the form of two bookends so to speak. What I mean is, I expect winter to come early, meaning Nov and Dec should be colder then avg. Then, in January, I expect to see the classic “January Thaw” occur, but don’t let this fool you. I expect winter to come back for Feb. and March. I expect a delayed spring like we saw this year when March was cold.

Monthly Break Down of Temps. and Snow Fall Amounts for KCVG

Nov – Below Avg for temps. and above normal for precip.

I expect the month of Nov to produce our first measureable snowfall for the winter season. We only avg 1.3” of snow for Nov. so getting any accumulation during the month is pretty much normal to above normal depending on how much we receive. I believe 2-4” of snow for the month is not out of the question.

Dec – Well below avg temps. and normal to slightly below normal in precip.

I expect Dec. to produce very cold conditions. Brutally cold weather and frequent arctic outbreaks will be the rule for this month. I expect to see numerous clipper systems affecting the region during Dec. I went with slightly below avg to near normal for precip. due to us a lot of the time having a cold, dry air mass in place. We avg. 3.7” for Dec., but since a lot of the precip. in Dec. should be in the form of snow, I expect snowfall to be above avg. here as well with amounts of 7-12” for the month as a whole possible.

Jan – Normal Temps to slightly above and above normal precip.

This is the month when I expect to see the pattern flip from cold to mild. We should have a chance at getting a good sized snow event or ice event here when the pattern decides to flip. We will see rain storms this month or mixed precip events at times as well. We avg. 7.9” for Jan. but due to the pattern change, I expect below avg. snow for the month of Jan in the 3-6” range.

Feb – Below Avg Temps and above normal Precip

Winter will make a come back in the month of February. Another good sized snow event is possible here when the pattern flips back to cold. Depending on when the flip occurs will impact the temp. and snow amounts that we receive. I am expecting slightly above normal snowfall here though. We avg. 6” for the month and I am expecting 6-9” for Feb.

March – Below Avg Temps and above normal precip.

Like this past March, I expect March of 2009 to be similar in terms of colder and wetter then avg. I think we have another chance here at a good sized snow event during the first half of the month. We avg. 3.8” and I expect normal to slightly above normal in terms of snowfall. I am forecasting 3-5” for March.

CVG Seasonal Snowfall Avg: 23.7”
Les’s Snowfall forecast: 21-38”
Target Number: 29.5”

The reasons why I have such a wide range of snow amounts listed are because snowfall is so difficult to forecast. One or two big storms can blow these numbers out of the water! My target number is 29.5” or 30” basically for KCVG. This is well above our normal of 23.7”.

I found the snowfall information here:

http://mcc.sws.uiuc.edu/climate_midwest/historical/snow/ky/151855_ssum.html


Conclusion

In conclusion, I expect temps overall for the entire winter season to be below avg. and precip. as well as snowfall to be above avg. for KCVG. What may make this forecast bust on the high side is if the NAO is too negative, and we see a suppressed storm track to the South and we get mainly clipper systems and lack of deep moisture that is needed for bigger snows. Also, a lot of storms would be Nor’ Easters instead of Appalachian tracks, which is what we like to see here. (March 2008 Blizzard for example). My forecast could also bust on the low side as well. Another idea I have been toying around with in my mind has been to take the record setting snowfalls of the Upper Midwest last year (WI, IL, MI, etc.) and shift that storm track a few hundred miles South. That would put us in the sweet spot here! Thus, 40-50” of snow would be possible in this scenario. So, I took a blend of both ideas and there you have it.