Forecast for the winter of 2012 - 2013

By: Dr. Jeff Masters , 4:53 PM GMT on October 18, 2012

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Expect increased chances of a warmer than average winter across most of the western U.S., and a cooler than average winter across much of Florida, said NOAA in their annual Winter Outlook, released on October 18. The forecast also called for increased chances of a wetter than average winter along the Gulf Coast, and drier than average conditions in the Pacific Northwest and Upper Midwest. This year's forecast was more difficult than usual to make, said Mike Halpert, deputy director of NOAA’s Climate Prediction Center, due to the uncertainty about what El Niño may do. El Niño strongly impacts winter weather patterns, by altering the path of the jet stream and the associated winter storms that travel along the axis of the jet stream. We currently have neutral El Niño conditions over the tropical Pacific ocean, which means that ocean temperatures are near average along the Equator from the coast of South America to the Date Line. But from early July to mid-September, a borderline weak El Niño event appeared to be consolidating, and most of the El Niño computer models were calling for a full-fledged El Niño event to be in place by winter. That is now seriously in question, as we've had four straight weeks with neutral conditions. NOAA's Climate Prediction Center has dropped their odds of a winter El Niño event to 55%. El Niño events typically cause cooler and wetter winter conditions across the Southern U.S., and warmer than average conditions across much of the Northern U.S.



Figure 1. Forecast temperature (top) and precipitation (bottom) for the U.S. for the upcoming winter, as predicted in the NOAA Winter Outlook, released on October 18.

What will the Arctic Oscillation and North Atlantic Oscillation do?
While El Niño is usually a key factor controlling winter weather patterns, it is often overshadowed by the North Atlantic Oscillation (NAO)--a climate pattern in the North Atlantic Ocean of fluctuations in the difference of sea-level pressure between the Icelandic Low and the Azores High. The NAO controls the strength and direction of westerly winds and storm tracks across the North Atlantic. A large difference in the pressure between Iceland and the Azores (positive NAO) leads to increased westerly winds and mild and wet winters in Europe. Positive NAO conditions also cause the Icelandic Low to draw a stronger south-westerly flow of air over eastern North America, preventing Arctic air from plunging southward. In contrast, if the difference in sea-level pressure between Iceland and the Azores is small (negative NAO), westerly winds are suppressed, allowing Arctic air to spill southwards into eastern North America and Europe more readily. This pattern is kind of like leaving the refrigerator door ajar--the Arctic refrigerator warms up, but all the cold air spills out into the house where people live. The NAO is a close cousin of the Arctic Oscillation (AO), and can be thought of as the North Atlantic component of the larger-scale Arctic Oscillation. Since the AO is a larger-scale pattern, scientists refer to the AO instead of the NAO when discussing large-scale winter circulation patterns. The winter of 2009 - 2010 had the most extremely negative NAO pattern (and AO pattern) since record keeping began in 1950. Vicious "Snowmageddon" winter storms occurred in both the U.K. and the United States that winter, as both Europe and North America suffered though an unusually cold and snowy winter (the NAO index was -1.67, beating the previous record of -1.47 set in the winter of 1962 - 1963.) Thus, the phase and strength of the AO/NAO pattern is a key factor controlling winter weather. Unfortunately, this pattern is not predictable more than about two weeks in advance, and thus was not considered by NOAA in their forecast for the upcoming winter.


Figure 2. The forecast for the winter of 2011 - 2012 released October 20, 2011 by NOAA called for a classic La Niña weather pattern over the U.S.--increased chances of warmer and drier weather over the Southern U.S., and cooler and wetter over the northern tier of states (top panels.) Nearly the entire nation ended up having a warmer than average winter, with the winter of 2011 - 2012 ranking as the 4th warmest winter on record. While the Southeast U.S. did see a very dry winter, as is typical in a La Niña year, Texas had an unusually wet winter. Part of the reason for the very mild winter was because the North Atlantic Oscillation (NAO), averaged over the winter, reached its most extreme positive value (+1.37) since record keeping began in 1950 (previous record: +1.36 during the winter of 1994 - 1995.)

Winter weather and the sunspot cycle
Another major influence on the AO and winter circulation patterns may be the 11-year solar cycle. Recent satellite measurements of ultraviolet light changes due to the 11-year sunspot cycle show that these variations are larger than was previously thought, and may have major impacts on winter circulation patterns. A climate model study published in Nature Geosciences by Ineson et al. (2011) concluded that during the minimum of the 11-year sunspot cycle, the sharp drop in UV light can drive a strongly negative AO pattern, resulting in "cold winters in northern Europe and the United States, and mild winters over southern Europe and Canada, with little direct change in globally averaged temperature." The winters of 2009 - 2010 and 2010 - 2011 both occurred during a minimum in the 11-year sunspot cycle and fit this pattern, with strongly negative AO conditions leading to cold and snowy winters in northern Europe and the Eastern U.S. There was more solar activity during the winter of 2011 - 2012, which may have contributed to the fact that AO conditions reversed, ending up positive. The coming winter of 2012 - 2013 will have even more solar activity than last winter (Figure 3), potentially increasing the odds of a warm, positive-AO winter in northern Europe and the United States.


Figure 3. The number of sunspots from 2000 - 2012 shows that solar minimum occurred during the winter of 2008 - 2009, and that solar activity is now approaching a peak, expected to arrive sometime in 2013. Image credit: NOAA Space Weather Prediction Center.

How will Arctic sea ice loss affect the winter?
Francis et al. (2009) found that during 1979 - 2006, years that had unusually low summertime Arctic sea ice had a 10 - 20% reduction in the temperature difference between the Equator and North Pole. This resulted in a weaker jet stream with slower winds that lasted a full six months, through fall and winter. The weaker jet caused a weaker Aleutian Low and Icelandic Low during the winter, resulting in a more negative Arctic Oscillation (AO), allowing cold air to spill out of the Arctic and into Europe and the Eastern U.S. Thus, summers with high Arctic sea ice loss may increase the odds of cold, snowy winters in Europe and the Eastern U.S. In my April 2, 2012 blog post, Arctic sea ice loss tied to unusual jet stream patterns, I discuss three additional research papers published in 2012 that argue for a major impact of Arctic sea ice loss on Northern Hemisphere weather in fall and winter, with sea ice loss causing an increase in the probability of negative-AO winters. But cold air may also be more likely to spill out of the Arctic in winter due to the decades-long pattern of warming and cooling of Atlantic Ocean waters known as the Atlantic Multidecadal Oscillation (AMO). A 2012 study by NASA scientists found that the warm phase of the AMO (like we have been in since 1995) causes more instances of atmospheric blocking, where the jet stream gets "stuck" in place, leading to long periods of extreme weather. It will be interesting to see how all these factors play out in the coming years. If these three newly-published studies are correct, the U.S. should see an increase in cold, snowy winters like 2010 - 2011 and 2009 - 2010 in coming decades, as Arctic sea ice continues to melt, affecting fall and winter atmospheric circulation patterns more strongly.

What happened during past winters with similar atmospheric conditions?
During a press conference today, Mike Halpert, deputy director of NOAA’s Climate Prediction Center, was asked to compare weather conditions this fall to those observed in previous years. The idea is that by looking at previous "analogue" years with similar progressions of the El Niño pattern, one might anticipate what the winter climate might be like. Halpert emphasized that this year is totally unique in the 63 years we've been keeping statistics on El Niño. Never before has an El Niño event begun to form in July and August, then quit in mid-September. Even if we did have a few analogue years, it wouldn't do any good, though--Halpert stated that we would need a data base of at least 1,000 years of historical data to make a skillful winter forecast based on analogue years.

Summary
I'm often asked by friends and neighbors what my forecast for the coming winter is, but I tell them to flip a coin, or catch some woolley bear caterpillars for me so I can count their stripes and make a woolley bear winter forecast (this year's Woolley Worm Festival in Banner Elk, North Carolina is this weekend, so we'll know then what the official Woolley Worm winter forecast is.) Making an accurate winter forecast is very difficult, as the interplay between El Niño, the AO/NAO, the AMO, Arctic sea ice loss, and the 11-year sunspot cycle is complex and poorly understood. I've learned to expect the unexpected and unprecedented from our weather over the past few winters; perhaps the most unexpected thing would be a very average winter during 2012 - 2013.

References
Francis, J. A., W. Chan, D. J. Leathers, J. R. Miller, and D. E. Veron, 2009: Winter northern hemisphere weather patterns remember summer Arctic sea-ice extent. Geophys. Res. Lett., 36, L07503, doi:10.1029/2009GL037274.

Honda, M., J. Inoue, and S. Yamane, 2009: Influence of low Arctic sea-ice minima on anomalously cold Eurasian winters. Geophys. Res. Lett., 36, L08707, doi:10.1029/2008GL037079.

Ineson, S., et al., 2011, Solar forcing of winter climate variability in the Northern Hemisphere, Nature Geoscience (2011) doi:10.1038/ngeo1282

Overland, J. E., and M. Wang, 2010: Large-scale atmospheric circulation changes associated with the recent loss of Arctic sea ice. Tellus, 62A, 1.9.

Petoukhov, V., and V. Semenov, 2010: A link between reduced Barents-Kara sea ice and cold winter extremes over northern continents. J. Geophys. Res.-Atmos., ISSN 0148-0227.

Seager, R., Y. Kushnir, J. Nakamura, M. Ting, and N. Naik (2010), Northern Hemisphere winter snow anomalies: ENSO, NAO and the winter of 2009/10, Geophys. Res. Lett., 37, L14703, doi:10.1029/2010GL043830.

Quiet in the Atlantic and Eastern Pacific
Forecasters at the National Hurricane Center get a rare break today, as there are no tropical cyclones or threat areas in either the Atlantic or Eastern Pacific to discuss. Most of the models are predicting that an area of disturbed weather capable of becoming a tropical depression will form in the Central Caribbean Sea south of Jamaica by the end of next week. Residents of Central America, Jamaica, Cuba, Haiti, and the Cayman Islands should anticipate the possibility of a multi-day period of very heavy rains affecting them late next week.

I'll have a new post on Saturday.

Jeff Masters

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Quoting Tropicsweatherpr:
12z CMC goes over Jamaica a a strong TS or Hurricane.

Link


Hi there,

The Canadian really likes that wave mentioned as AOI #2. With the MJO at work the rest of this month could become very active in short order. With the GFS and Euro sticking with the SW Caribbean as the focal point, this weekend would be the probable start of whatever is likely to develop. TAFB surface maps may soon show a forecasted surface low near 75W.
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Quoting GTcooliebai:
Latest Canadian Model has the storm right over Jamaica.


Also note that it develops the wave in the Central Atlantic into a potent tropical system.
Member Since: July 6, 2010 Posts: 113 Comments: 32338
Quoting 12george1:
So does a hurricane in Florida at the end of October look more likely with that system in the Caribbean?

The prospects of a tropical cyclone developing in the Caribbean this upcoming week are as high as ever. However, the models no longer show the system as intense as what they once did, and most keep it east of Florida...which is a good thing.
Member Since: July 6, 2010 Posts: 113 Comments: 32338
Latest Canadian Model has the storm right over Jamaica.

Member Since: August 31, 2009 Posts: 0 Comments: 5628
So does a hurricane in Florida at the end of October look more likely with that system in the Caribbean?
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12z CMC goes over Jamaica a a strong TS or Hurricane.

Link
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Quoting aspectre:
406 Civicane49: 92C

My first thought was, "My, that's really warm..." thinking about a 92degree SeaSurfaceTemperature in Fahrenheit (though reading Celsius), then did a doubletake when my brain finally caught up with the "C".
THEN, I thought of 92C as a storm in the Pacific


Well it IS almost December.
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Member Since: August 6, 2011 Posts: 4 Comments: 39690
Quoting aspectre:
406 Civicane49: 92C

My first thought was, "My, that's really warm..." thinking about a 92degree SeaSurfaceTemperature in Fahrenheit (though reading Celsius), then did a doubletake when my brain finally caught up with the "C".
THEN, I thought of 92C as a storm in the Pacific
how did the interview go?..hope you got it.
Member Since: August 6, 2011 Posts: 4 Comments: 39690
406 Civicane49: 92C

My first thought was, "My, that's really warm..." thinking about a 92degree SeaSurfaceTemperature in Fahrenheit (though reading Celsius), then did a doubletake when my brain finally caught up with the "C".
THEN, I thought of 92C as a storm in the Pacific
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429. 7544
Quoting GTcooliebai:
GFS once again splits up the system as it tracks through the Windward Passage with a piece going out to sea and another piece heading towards FL.



eruo was first on the split a couple of days ago so it could be
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Quoting GTcooliebai:
Starting to come around to the idea of the European solution. The models may be taking into account the mountainous terrain this system will pass over.
yes you could be right there
Member Since: August 6, 2011 Posts: 4 Comments: 39690
427. 7544
hmmmm 2 yellow circles interesting could one become 99l soon p but would the atl system moving wnw now go more west with the high building in ? tia
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remember those guys laughing at the gfs LAST WEEK?..NOT LAUGHING NOW HUH..gfs is great at the 10 day mark.......
Member Since: August 6, 2011 Posts: 4 Comments: 39690
Quoting LargoFl:
GFS at next friday, there's the 2 storms below florida...............................and..take note of that huge storm by the great lakes next friday..whew
Starting to come around to the idea of the European solution. The models may be taking into account the mountainous terrain this system will pass over.
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Quoting SouthTampa:
With the sun in that position you'd think we're on Tierra Del Fuego!
..LOL
Member Since: August 6, 2011 Posts: 4 Comments: 39690
GFS at next friday, there's the 2 storms below florida...............................and..take note of that huge storm by the great lakes next friday..whew
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Quoting LargoFl:
With the sun in that position you'd think we're on Tierra Del Fuego!
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Quoting Tropicsweatherpr:
Invest on SW Caribbean in a couple of days or sooner?
next week possibly thursday
Member Since: August 6, 2011 Posts: 4 Comments: 39690
Invest on SW Caribbean in a couple of days or sooner?
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GFS at 144 hours, Thursday its there and we watch it.......................and notice that huge front in the midwest
Member Since: August 6, 2011 Posts: 4 Comments: 39690
Member Since: August 31, 2009 Posts: 0 Comments: 5628
Member Since: August 6, 2011 Posts: 4 Comments: 39690
Finally i´m seeing this negatives numbers in all our hemisphere, will be interesting see in what develops the system in the caribbean


MJO for long period seems to be
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whew just did the lawn etc, wow soaking wet but the shower felt great, the humidty..is still here in my area,I can attest to that LOL...come on cooler weather please.....
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GFS once again splits up the system as it tracks through the Windward Passage with a piece going out to sea and another piece heading towards FL.

Member Since: August 31, 2009 Posts: 0 Comments: 5628
We've got ourselves yellow in the Caribbean, finally something to track.
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412. Skyepony (Mod)
Fresh OSCAT of the Central Atlantic blob..
Member Since: August 10, 2005 Posts: 178 Comments: 38321
Yellow circle in the Caribbean.

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT FRI OCT 19 2012

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A TROPICAL WAVE INTERACTING WITH AN UPPER-LEVEL LOW IS PRODUCING
WIDESPREAD CLOUDINESS AND THUNDERSTORMS OVER THE CENTRAL TROPICAL
ATLANTIC ABOUT MIDWAY BETWEEN THE NORTHERN LESSER ANTILLES AND THE
CAPE VERDE ISLANDS. UPPER-LEVEL WINDS ARE CURRENTLY NOT CONDUCIVE
FOR DEVELOPMENT...BUT COULD BECOME SLIGHTLY MORE FAVORABLE IN A DAY
OR SO. THIS SYSTEM HAS A LOW CHANCE...10 PERCENT...OF BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES SLOWLY
WEST-NORTHWESTWARD OR NORTHWESTWARD.

A LARGE AREA OF DISTURBED WEATHER OVER THE EASTERN AND CENTRAL
CARIBBEAN SEA IN ASSOCIATION WITH A WESTWARD-MOVING TROPICAL WAVE.
ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR SLOW DEVELOPMENT OF THIS
DISTURBANCE DURING THE NEXT FEW DAYS. THIS SYSTEM HAS A LOW
CHANCE...10 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.

ELSEWHERE...TROPICAL STORM FORMATION IS NOT EXPECTED DURING THE NEXT
48 HOURS.

$$
FORECASTER KIMBERLAIN
Member Since: July 6, 2010 Posts: 113 Comments: 32338
410. Skyepony (Mod)
ncstorm~ That was a week ago. Even more stale..

Fairly fresh partial ASCAT of the Central Atlantic blob is much preferred...
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Day 7:

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408. wxmod
Quoting ncstorm:
I am really disliking the blog with the worshipping of several posters..Aussie never called anyone a Liar including Dr. Masters..I even took 30 minutes out of my time from work to read the entire blog where the alleged name calling of Dr. Masters supposedly took place. Please read for yourself..

I just wish people would have a mind of their own and not go on heresy from a poster just to be in the "in crowd" on WU which sounds ridiculous if you ask me..remember, just because someone says it on the internet doesnt make it true..

Have a blessed day and remember to be kind to others!

I wish everyone would just post new information. There's some interesting stuff happening out there if you just look for it.
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92C:

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I always find that this blog slows down on Friday afternoons. People leave work early or try to finish work before leaving so no time to surf the blog. And of course, during winter it is very slow in here. However, there are a few faithful who come on to talk about weather anywhere in the world. I like this blog. I think the contentiousness will ease off after the elections. I think the combination of economics, politics and everyday hassles leave a few people testy. Accusations don't help ncstorm. Let's all be nice to each other because after all, we are all One Human Family.
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404. wxmod
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Good afternoon everyone. It is slow in this blog. And my eyesight is getting wacko. Must be time for new glasses. I was going to minus someone and instead hit the report. I hope Admin forgives my blunder for reporting something that should not be.
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Day 4:



Day 5:



Day 6:

Member Since: July 6, 2010 Posts: 113 Comments: 32338
I am really disliking the blog with the worshipping of several posters..Aussie never called anyone a Liar including Dr. Masters..I even took 30 minutes out of my time from work to read the entire blog where the alleged name calling of Dr. Masters supposedly took place. Please read for yourself..

I just wish people would have a mind of their own and not go on heresy from a poster just to be in the "in crowd" on WU which sounds ridiculous if you ask me..remember, just because someone says it on the internet doesnt make it true..

Have a blessed day and remember to be kind to others!
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Quoting TropicTraveler:
Interesting report today Dr. Masters. Being an Arizona resident, I'm not used to cold weather and shiver in sympathy at the thought of extra cold winters. Right now I'm working for a time in Baton Rouge Louisiana to the smell of the refineries blowing over us, and wondering if people get used to it over time. Also wonder what particulates might be present to cause that smell. The air looks clean, just smells stinky.
I lived in Baton Rouge for a few years some time ago. I remember an obvious stink being present only when winds from the north brought the smell from a paper mill.(Maybe different now, though.)
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This is the beginning of our potential Caribbean tropical cyclone, if anybody is wondering.

Member Since: July 6, 2010 Posts: 113 Comments: 32338
Neapolitan

You have new W Mail
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Can really tell I'm in the NW flow of that low Keeper, my county and StL only at 49, Spfld, IL only 46 - according to the top of my WU page. At least it looks like it's drier for now - hate cold rain. Rem when I went to So. IL Carbondale, they'd get those 33 degree rains, much rather have snow!
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Quoting GeorgiaStormz:


Good morning all and TGIF (TGIS for you Aussie). I do miss the beautiful fall foliage from when I lived up North. Looks like this weekend should be fairly pleasant for most of the US with convection levels being pretty stable and no major systems coming through for a couple of days. Perfectly timed for the weekend.
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Quoting clwstmchasr:


Unfortunately I think there are people being run off or in some cases banned from this blog.
well i have seen in the middle of the off seaon the blog get less than 50 comments in 24 hrs at times most are done with cane season i reckon unless something is to pop up
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Lots of color in S C IL right now. Only Red Maple? I have hard maples that are orange/purple that drop early and another that turns yellow (just now turning) and drops later. The hickories in the Kaskaskia drainage were really popping last week. Headed down eastern side of IL basin day before and not nearly as much color. Looks like oaks are going to be a little more colorful this year too - I guess those Aug/Sept rains helped. (If this rain/wind doesn't knock too many off today)

97 - I'm getting my Here Kitty Kitty shirt from '06 ready! Rem what happened last time a triple crown winner's team faced the Cards in the WS.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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