Only a Few Weeks Late: Winter/Spring Review, Summer, Tropics and Oil

So I promised another entry and failed to deliver. Since there's a lot to cover, I'll try and be brief here and keep it simple.

Winter Outlook Review

My first real legitimate crack at a winter forecast, and, well....that's why it was my first.

You can compare and contrast the maps as follows:

December Forecast
January Forecast
February Forecast

Here are the actuals...

December 2009
January 2010
February 2010

December wasn't great. Got the southern part generally right (though I was too cool in FL), but the Rockies/N Plains killed me. January was better, but I was too cool in the West and Northeast and a little too aggressively warm in the N Plains (as well as the Corn Belt). February was better still, but still too warm in the Northern Plains, but not nearly warm enough in New England.

Just to sum things up, in a typical El Nino year, especially one of this strength, you would see a warmer outcome in the northern part of the country. But this past winter was incredibly unique, in that we not only had a strong El Nino, but the dominant signal was overtaken by incredibly strong "blocking" in the atmosphere (over Greenland, over the Arctic and over the Northwest). We don't have a good data set which suggests we've had a year with all of these factors in place at the same time (they've all happened independently at some point or another, but not really quite together like this). So many lessons were learned from following this winter and trying to feel out how certain things impacted other things.

Spring Outlook Review

So how did I do in spring? Let's look.

March Forecast
April Forecast
May Forecast

March 2010
April 2010
May 2010

In March I had the right ideas, but I wasn't quite warm enough in the Northern Tier of the US. April worked out very well all things considered. I did not grab the cold signal on the West Coast and I was way too cool on the East Coast (should have expanded the above normals to the coast). May worked in the interior Southeast and Southwest, but that was about it. Messy month. My theory that another cool cut-off low season in the Northeast would occur did not pan out (though it did snow on Mother's Day in interior PA and NY). More blocking in play in spring. a rapid decline in El Nino strength, and a very active jet coming out of the Pacific (basically a parade of troughs) helped to shape the springtime. Additionally, the severe weather forecast worked out okay for the most part, with below normal activity until a fairly active May.

So lessons were learned and hopefully I can apply them in future outlooks (and hopefully we see some improvements).

Summer

So you saw the summer outlook. The general ideas look okay, though I think June is going to come in warmer in the West than advertised and July might end up being warmer. It sure looks warm though. A warm Atlantic and a developing La Nina in the Pacific is going to help matters, making this probably the warmest summer in some time.

Tropical season will be busy. You can see the map of global water temperature anomalies (basically how much warmer or cooler than normal things are). The Atlantic, for lack of a better word, is boiling. The Gulf (which was running below normal a couple months ago) is boiling. The Caribbean is boiling. Dust from the Sahara Desert (which may have helped further mitigate recent hurricane seasons in addition to other factors) is predicted to be below normal. Tropical forecasts from NOAA and Colorado State are bullish. And they should be. Parameters for tropical development are about as good as they could ever be right now, and assuming that lasts deeper into summer, look out. My tropical outlook is in the summer outlook link above.

Oil and Hurricanes

So I've gotten a couple questions from people about what it might mean that we have millions of gallons of oil in the Gulf of Mexico and a forecasted hellish hurricane season.

For some really good details on what it may mean, I encourage you to read a blog entry posted by Dr. Jeff Masters at Weather Underground. Here's a slightly condensed summary of what could happen:

- We haven't had a situation very similar to this in recorded history.

- The largest oil spill on record in the world occurred in the Gulf in 1979. A hurricane passed a ways away from the spill in the middle of it, provided large swells and 30-35 mph winds, and didn't noticeably alter the spill itself. However, the Texas coast, impacted by oil, was actually cleaned of it when the hurricane combined with a non-tropical low to produce heavy rain and pretty decent swells in that region. However, the hypothesis is that this would work for beaches, but not marshland. In general though, a hurricane would actually help the beaches most likely.

- What goes up, must come down. While a lot of the onshore oil would be washed away and diluted, if a hurricane spun up over the oil slick area, there is the potential that a relatively contained oil spill could become a very widespread mess. For instance, during Exxon Valdez, after a storm with 70 mph winds passed over the spill area, what was actually a contained and under control spill, ended up spreading out over 90 miles of coast, which later grew to 400 miles and thus became a disaster.

- The good news is that the Loop Current (which is a rotating circulation in the Gulf of Mexico) actually appears to be splitting off and spinning into an eddy in the Gulf...which means that it's cut off from the rest of the ocean circulation, meaning that if oil gets trapped in it, it won't be redistributed around the Florida Keys and up the East Coast. However, that can also help fuel stronger tropical systems, so pick your poison.

- Additionally if a hurricane strikes, and the oil is redistributed into the eddy, you might have this eddy spinning with oil in the middle of the Gulf. Typically after a hurricane passes, the cold water below gets upwelled to the surface, cooling the overall ocean profile. Given that oil, being dark, may help to absorb sunlight in the Gulf eddy (which actually runs to fairly great depths) it may help to slightly increase water temperatures instead and thus if the right conditions for storms to track into the Gulf develop, you could be looking at several significant storms this summer. But...this is a limited concern. The activity is going to happen with or without oil, it's just a question of whether it may be aided by warmer water temperatures partially thanks to oil.

- The biggest concern and impact would be if a hurricane took the right track to the left of the majority of the oil, and ran inland with a high storm surge. The potential does exists that miles and miles of coastline and even inland areas might end up with a toxic, soupy mixture of oil and seawater. There has been an instance where this occurred with a leak from a nearshore refinery that ended up depositing oily sediment in an area with 1,800 homes. Spread that out over 20, 30, 50, 75 miles of coastline and that could be the proverbial worst case scenario.

- Wind driven sea spray will likely have at least traces of oil in it and hurricanes tend to fling sea spray well inland (the 1938 New England hurricane sent enough salt particles to damage trees 45 miles inland). If some of this ends up getting flung into areas that don't see much rain from the storm...or enough to dilute it, that could cause ecological damage well away from the coast, but frankly, there's no prior case of this happening, so this falls into the category of unknown.

- In terms of rain, the odds suggest that while there will be traces of oil in the rainwater, it'll be so miniscule that it probably would have no impact on health or ecology.

- The huge undersea plumes of oil that have been detected at the Gulf probably would not be impacted by a hurricane passing over them, as hurricanes generally only affect the upper 700 feet of the ocean and these plumes were detected below 2,000 feet. However, if that rises with time, that'd be another story.

- Summary: Lots of unknowns and depending on the track of the storm, a hurricane could either help mitigate the disaster (while creating its own set of problems) or it could exacerbate it.

Unfortunately we'll just have to wait and see.

Please feel free to post suggestions for topics here or on my Facebook profile! I'll be glad to entertain anything you'd like to know more about!

Summer Outlook Preview

Just wanted to give a brief overview of my thoughts for summer. You can see the maps. All unofficial, but gives you an idea of where I'm coming from. Then a few quick notes.

It does look like the potential exists for the hottest summer in awhile on a national level. A lot of the analog (or similar) years I was finding were from the mid 80s to the mid 90s, which was a very warm period overall. And the best match years I found were warm overall. In addition, it is likely that El Nino's opposite, La Nina is beginning to form in the Equatorial Pacific. This traditionally lends to a hotter than normal summer.


Additionally, hurricane season should be busy...very busy. All the ingredients are on the table for an extremely active year. Many things can always go wrong, but the average of the best tropical years I found and the best temperature years I found was close to 14-15 storms, which included years outside of the recent active period.

My unofficial/official forecast is 16 named storms, 12 hurricanes and six major (Category 3 or higher) hurricanes. This is subject to and probably will change, so check back in on the next post...still have some fine tuning to do on that.

In the next day or two, I'll post a more detailed entry, going over....

a.) A verification of the winter and spring forecast maps, with some explanation as to what did and did not work.

b.) Risk factors associated with entering a potential La Nina period (weak vs. moderate vs. strong) as well as the risk if we never really make it to full fledged La Nina.

c.) More information on hurricane season.

d.) A quick look at what the current developments in the Pacific could mean for next winter.

Lastly, here's my primary analog list, with some tweaks and chiseling to how I weighted things here and there: 1953, 1979, 1984, 1987, 1998, 2003, 2007.

Thoughts, comments, questions...fire away.

Looking Forward...

So it's been a couple of months. After the snow stopped and I lost some direction here, I figured I would abandon ship. But now that the weather here in Southern California is going to become unbearably boring, I'd like to throw down some thoughts on things like summer heat, hurricanes, severe weather, etc.

What I'd like to know though is what, if anything, people want to hear about/read about? I've mainly been used for snow forecasts, which I'm fine with, but there is a much bigger world out there! :) So drop a comment here or on Facebook on what you might have an interest in, so I can get some direction as summer approaches. Thanks!

The Arctic Oscillation and Winter 09-10: A Piece of the Puzzle

This latest entry is going to focus on the past winter (since we're now in meteorological spring!) and one of the main drivers in what made this one so memorable in much of the East and South.

If you'll recall a couple weeks back, I posted a lengthy blog trying to debunk people using this winter to prove or disprove the theory of anthropogenic global warming. I mentioned in that entry that one of the biggest issues about people trying to use this year as proof of anything was that this was the first time we've had both an El Nino and the Arctic Oscillation at such sustained strong levels since at least the 1960s, and even that's a loose match.


What the Heck Is It?

Here's a quick primer on the Arctic Oscillation (AO). The AO is basically a gauge of blocking in the upper levels of the atmosphere over, not surprisingly, the Arctic. Blocking is pretty much what it sounds like. The overall weather pattern in a blocking pattern becomes "blocked up," meaning certain aspects sustain themselves for days, if not weeks at a time. When the Arctic Oscillation is in its negative phase, a large area of high pressure in the upper atmosphere basically sits over the Arctic. Underneath the high, temperatures get warmer than normal and the cold air is forced to be displaced. Traditionally, it's shunted southward, right into the Central and Eastern US in North America and straight into the heart of Europe and parts of Asia. You're basically forcing the coldest air, relative to normal, to leave the Arctic and it oozes south. The further south you live in the US, generally, the colder, relative to normal, it is.

Here's a visual primer on the AO. The top part is the positive phase of the AO. The bottom part is more representative of this winter and the negative phase of the AO.

So How Odd Was This Winter?

If you click the chart above, you'll see a running graph of monthly Arctic Oscillation values since 1990. Notice how things tank at the end of the chart for this winter. So we're automatically at the most sustained negative levels of the AO that we've seen anytime in the last 20 years.

People may argue, "Well, look at the AO and how it's tanking. That's not normal. That's clearly an indication that something is changing in the Arctic." Well, the picture's a little different when you look at the AO since 1950. Click the image below to enlarge.

Notice that since 1950, we've had several instances where the AO has tanked. For my purposes, my definition of "tanked," will be when the average AO monthly value ends up under -3. It happened in the winters of 1962-63, 1965-66, 1968-69, 1976-77 and 1977-78. We came close in 1984-85 and 1985-86. Unfortunately, data only exists back to 1950 and we can't see any serious long-term trends.

But it is interesting how there was a build up in the 1950s and by the mid-1960s, the AO tanked and held low for 5-8 years, followed by a break from ~ 1971-1976. We tanked again in 76-77 and stayed generally low until 1986. We started seeing more negatives in the AO around 1995-96 and continuing periodically through this year, when it tanked. I'm wondering if we aren't entering a period of 4-8 winters where we're going to see the AO stay at a very negative level, helping to supply more cold than we've been accustomed to seeing lately.

At any rate, with the AO as negative as it was this year, we pretty much had (with a few exceptions) an almost continuous supply of cold air draining out of the Arctic and helping to supply sustained cold weather for the Plains and Midwest (contrary to typical El Nino conditions). It also helped supply enough cold in the East (especially the further south Mid-Atlantic, Southeast and Southern Plains...areas that normally would have been borderline for rain/snow) to keep many storms this winter as all snow. The plentiful amounts of moisture were primarily courtesy of El Nino. The mechanism to help keep it snow, was likely due largely in part to the pattern over the Arctic.

Remember, the AO is just one piece of a much, much larger puzzle. But the main point is, while it's unusual for us to have seen the AO this negative in recent years, it does fall within the realm of reason of the last 60 years.

A Spring Outlook

Well, I took a crack at winter this year a little more rigorously than in year's past, and I'll go over the results of that forecast sometime in the next week or two. Disappointed on the whole regarding the specific forecast, but I took quite a bit from this winter and following it on a larger scale day to day that will help me in the long run I think.

So with some of that in mind, I decided I would take a shot at Spring. Not an easy outlook, but I did find a few things to look at. We still have an El Nino in the Pacific, but it has begun the typical seasonal decline we typically see in late winter/early spring. Whether it completely fades away or not is another question entirely (mainly a question for summer anyway). El Ninos are difficult to try and make predictions for. But the computer model projections shown above indicate that at the very least a weak El Nino should be in place through all of spring.

Additionally, I did some research on some of the extreme atmospheric blocking we've seen this winter and if it correlates to anything in Spring, and there seems to be some agreement for blocking to at least maintain itself through mid-April in some fashion, albeit weaker. There were a handful of years where blocking really went to the opposite side of the scale starting as early as the first week in March. We are heading in that direction in the short term (not entirely going to the other side of the scale, but weakening considerably.

I looked at a number of other things as well, mainly experimenting to see if I find a useful method. I basically found the years where a number of trends were similar and bunched those years together, filtered out any that were completely opposite in the Pacific (La Nina instead of El Nino for instance) and used those as base analogs. I then looked at some things exclusive to the East and some things mainly dominant in the West and put some extra weight on those years for those regions and blended my analog ideas together for a national map.

So with that said, below you'll find my March, April and May temperature outlooks (click them to enlarge).

Additionally, I'm thinking wetter than normal conditions will persist in the South initially, though the focus may shift into the Southern Plains and Central Mississippi Valley this month, with continued generally wet conditions on the West Coast, Southwest and in the Mid-Atlantic/South Florida. There was a signal for a considerably drier than normal Gulf Coast as well, but I'm not entirely sure I believe it. We'll see. There was also a signal for a drier than average Ohio Valley and Northeast as well. Again, we'll see.

In terms of severe weather, climatology would favor active severe weather in the Southeast in a spring like this. In terms of tornadoes specifically, here are some findings based on the years I'm looking at:

- Well below the rolling three year average for March and April (138/194 tornadoes)
- And near to slightly below the rolling three year average for May (305 tornadoes), with a slight risk of above.
- Late April to Late May being the most active periods. The first period of activity looks to be around March 10th perhaps, with the models indicating a potentially potent Mid-Continent storm.
- Perhaps a greater than usual risk for significant tornadoes in the Southeast

That's my call and we'll see how it goes!

Mid-Week Storm, Spring Outlook Preview

Well it looks like we're going to get a good storm this week, but the problem is that it's probably going to be a miss for most areas in the Northeast. The best chance for any snow with this storm is going to be from Atlanta north into the mountains of North Carolina, as well as far Eastern North Carolina and Southeast Virginia. There's a secondary chance that snow will be able to extend onto the Jersey and Delaware shores, as well as potentially Eastern Long Island and Cape Cod late Tuesday night into Wednesday morning...later up north. A weak disturbance will provide the interior with some scattered snow/rain showers on Wednesday.

There are a couple things holding this back. The pattern overall is too progressive...it's moving forward too much. You're not able to phase together the disturbances shifting East. The storm from last week is just now starting to exit, which is a bit too late to get the players on the field lined up properly to score a storm further inland. And the large ridge of high pressure in the upper atmosphere out West is centered over Wyoming and Montana. For a good coastal storm, that needs to be centered closer to Boise, ID. It's becoming too late in the game for this to really change.

So my overall feeling for plowable snow is:

North and West of I-95: Limited to No Risk
Jersey/Delaware Shore: Low Risk
Eastern Long Island: Low Risk
Cape Cod: Low to Medium Risk
Southeast VA/Eastern NC: Low to medium risk
Central/Southern NC through ATL: Medium risk

The biggest problem in the Southeast is that it's now March and you have warmer surface temperatures and a stronger sun than you had even 2-3 weeks ago. It can snow and it can accumulate in the South in March, but I'm not sure this is going to be the best setup for it.

I'll post an update on the evening data when it rolls in.

In other news...

Tomorrow, I'll post my Spring Outlook with a brief overview of what I think we can expect for March, April and May. Just a preview, I don't think winter is entirely over yet, but we're certainly running out of time. The big question is whether parts of the East can break the funk of the last couple April/Mays. I'll try and answer that for you tomorrow.

Closing the Door on An Amazing Storm

A fairly amazing storm this one was. It may not have been the most widespread, biggest, largest, most worstest storm in all of forever as the hype leading into it by certain outlets made it out to be. Nor was it a redux of the Blizzard of 1888 by any means as others also made it out to be. But it was a big, unique, intriguing storm, one of the strongest and biggest for parts of the Catskills, Poconos, Northern NJ and New York City in a long, long time. It also was no cake walk in New England either. Just snow does not a storm make, and parts of New England were battered by rain, flooding and incredibly powerful winds.

The barometric pressure of the storm appears to have bottomed out at 972 mb, which is the equivalent of about a category two hurricane. It doesn't mean the impacts were akin to a hurricane (the storm develops by a much different process than tropical systems do), but it certainly packed a mean punch as it moved from about Cape Cod across New England to a position right near New York City.

One of the incredible things about NYC is that as of yesterday afternoon, Central Park had recorded 5.5" of snow in almost 1.5" of liquid. They are now approaching 21", passing 1996 and could actually exceed their total from 1888 (21.0"). The amazing December 1947 and February 2006 storms however remain pretty well out of reach (26+). But most of what fell in NYC fell over 12 hours last night, which is a huge hit. Because the storm is overhead, the wind is not nearly as bad as it could be and that's why this will fall well short of 1888's benchmark.

Some highlights regarding the wind and rain and some snow in New England....

- 2-4" of rain across Massachusetts, Connecticut, Rhode Island and southern New Hampshire and 4-8" fell in parts of Maine and the rest of New Hampshire leading to widespread flooding.

- Up to 40" of snow fell in the mountains of New Hampshire.

- Peak Wind Gusts: 67 mph Beverly, MA, 60 mph Boston, 63 mph Manchester, NH, and 50 mph at Worcester.

- A laundry list of damage reports from Massachusetts, Connecticut, Rhode Island and S New Hampshire can be found here: http://forecast.weather.gov/product.php?site=NWS&format=CI&version=1&glossary=0&highlight=off&issuedby=BOX&product=LSR

- The list of reports from Central and Northern New Hampshire, as well as Maine is here: http://forecast.weather.gov/product.php?site=NWS&format=CI&version=1&glossary=0&highlight=off&issuedby=GYX&product=LSR

- The list of reports from the New York City Metro Area is here: http://forecast.weather.gov/product.php?site=NWS&issuedby=OKX&product=LSR

In terms of snow elsewhere, here are the top 5 totals in each region....

Southeast NJ
Hammonton: 5.1"
ACY: 5.0"
Pleasantville: 5.0"
Somers Point: 4.0"
Woodbine: 3.5"

Philly Suburbs NJ/Trenton
Ewing: 8.2"
Tabernacle: 7.8"
Mount Holly: 6.6"
Mount Laurel: 6.4"
Hightstown: 6.0"

Philly & Suburbs PA/Allentown
Martins Creek: 14.7"
Bethlehem: 13.7"
Nazareth: 12.0"
Allentown: 12.0"
Montgomeryville: 11.5"

Central NJ
Newtown: 18.0"
Edison: 13.5"
Colts Neck: 12.0"
Old Bridge: 12.0"
Englishtown: 12.0"

Northwest NJ
West Milford: 28.0"
Montague: 26.5"
Sparta: 21.5"
Wantage: 20.0"
Oak Ridge: 16.0"

Northeast NJ
Roselle: 21.4"
Bergenfield: 21.0"
Mahwah: 20.0"
Ramsey: 18.5"
Lodi: 18.3"

New York City/Long Island
Great Kills (Staten Island): 26.0"
Central Park: 20.8"
Pelham (Bronx): 20.0"
Bedford Park (Bronx): 19.5"
Douglaston (Queens): 16.8"

Orange County
Monroe: 31.0"
Goshen: 27.4"
Warwick: 23.0"
Vails Gate: 22.5"
Walden: 22.0"

NYC N Suburbs (Rockland, Putnam, Westchester)
Bronxville: 21.0"
Chappaqua: 21.0"
Suffern: 17.0"
Valley Cottage: 17.0"
Yonkers: 16.4"

Maine/New Hampshire
Franconia Notch, NH: 39.0"
Randolph, NH: 37.6"
Jackman, ME: 22.0"
Madison, NH: 17.8"
Conway, NH: 17.0"

Massachusetts/Connecticut/Rhode Island
About 8" in the Berkshires, but snow will continue occurring in parts of Massachusetts and Connecticut through the day.

Vermont (May be updated)
Woodford: 8.5"
Magic Mountain: 7.0"
Bromley Mountain: 4.0"
Mt Snow: 4.0"
Stratton Mountain: 4.0"

Adirondacks
TBA

Eastern NY (Albany-Newburgh)
Hunter Mountain: 30.0"
Prattsville: 30.0"
Slide Mountain: 29.0"
Platte Cove: 24.9"
Highmount: 24.0"

Northern Catskills-Eastern Mohawk Valley
North Blenheim: 30.0"
Fulton: 28.0"
Richmondville: 25.0"
Sloansville: 25.0"
Delanson: 20.0"

Utica Region
Verona Beach: 21.0"
Westmoreland: 21.0"
Warren: 18.0"
Oneida: 17.9"
Whitesboro: 17.1"

Otsego/Delaware/Sullivan Counties
Stamford: 36.0"
New Kingston: 32.0"
Worcester: 28.0"
East Worcester: 26.0"
Margaretville: 26.0"

Syracuse Area
Cortland: 21.0"
Moravia: 21.0"
Cazenovia: 19.0"
Willet: 16.5"
Clay: 16.1"

Finger Lakes
Smithboro: 23.7"
Ithaca: 19.5"
Aurora: 16.0"
Danby: 16.0"
Freeville: 15.9"

Western New York
Tyrone: 17.0"
Caton: 14.0"
Rochester: 11.9"
Bath: 11.5"
Newark: 10.6"

Southern Tier
Smithboro: 23.7"
East Nichols: 23.6"
South Vestal: 18.9"
Binghamton Airport: 16.3"
East Maine: 14.6"

Northeast PA
Bear Creek: 28.0"
Tobyhanna: 25.0"
Jessup: 21.0"
Pocono Peak Lake: 20.5"
Glenburn: 19.9"

Central PA
Laporte: 12.0"
Mahanoy City: 11.2"
Ebensburg: 8.0"
Patton: 8.0"
Kane: 7.8"

Western Maryland/West Virginia/Southern PA
Bayard, WV: 33.2"
Garrett County, MD: 28.0"
Oakland, MD: 23.0"
Champion, PA: 16.0"
Rowlesburg, WV: 15.0"

Maryland/Delaware
Frostburg, MD: 4.7"
Colora, MD: 4.5"
Bear, DE: 3.1"
Wilmington, DE: 3.1"
New Castle, DE: 3.0"

What About Next Week?

Well, it's still way too early to get too excited. But the models continue to advertise a large storm off the East Coast coming dangerously close to being another major snowmaker for many areas from DC to NYC. There are a couple of reasons to be on the side that this storm will happen, as there are some reasons to think it may not. We're going to get probably our 2nd strongest storm of the winter here in SoCal this weekend. The last time this happened, that energy spread downstream and developed into a series of storms that battered the coast (late Jan/early Feb). The moisture will be in place. Now the question is what happens with the storm over the Northeast this weekend? If that can get far enough out of the way, it opens the door to allow this next storm to ride up the coast. If this Northeast storm is too strong, it essentially block any mechanism to allow next week's storm to lift and it would scoot underneath the remnants of this weekend's system and out to sea, likely only bringing snow to parts of VA and NC. A lot to be determined regarding this setup....we'll see what the trends are over the next couple days, and I'll keep you posted.