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

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

A WESTWARD-MOVING TROPICAL WAVE LOCATED SOUTH OF HISPANIOLA IS
INTERACTING WITH AN ELONGATED TROUGH OF LOW PRESSURE THAT EXTENDS
FROM NICARAGUA EASTWARD TO THE SOUTHERN WINDWARD ISLANDS. THIS
BROAD DISTURBANCE IS PRODUCING WIDESPREAD CLOUDINESS AND SHOWERS
OVER MUCH OF THE SOUTHWESTERN...CENTRAL...AND EASTERN CARIBBEAN
SEA...AND ADJACENT LAND AREAS OF COLOMBIA AND VENEZUELA. OVER THE
NEXT FEW DAYS...ENVIRONMENTAL CONDITIONS ARE EXPECTED TO GRADUALLY
BECOME MORE CONDUCIVE FOR DEVELOPMENT TO OCCUR ACROSS THE CENTRAL
AND SOUTHWESTERN CARIBBEAN SEA. THIS SYSTEM HAS A LOW CHANCE...20
PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS
AS IT MOVES SLOWLY WESTWARD.

A TROPICAL WAVE INTERACTING WITH AN UPPER-LEVEL LOW IS PRODUCING
WIDESPREAD CLOUDINESS AND SCATTERED THUNDERSTORMS OVER THE CENTRAL
TROPICAL ATLANTIC ABOUT 1000 MILES EAST OF THE LEEWARD ISLANDS.
DEVELOPMENT...IF ANY...OF THIS DISTURBANCE SHOULD BE SLOW TO OCCUR
DUE TO UNFAVORABLE UPPER-LEVEL WINDS. THIS SYSTEM HAS A LOW
CHANCE...10 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS AS IT MOVES SLOWLY WEST-NORTHWESTWARD.

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

$$
FORECASTER STEWART
Member Since: July 6, 2010 Posts: 113 Comments: 32524
Quoting LargoFl:
what the NWS is watching in regards to cuba is a storm development in the southern caribbean then moving notheastward over cuba or therebouts..my guess is the atlantic storm turns NE up towards the bahamas maybe even before getting to the islands..we'll see next week
the atlantic low? you meant north west towards the bahamas...north of the island, similar, but more North westward than Rafael..
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Quoting Skyepony:
Asheville, NC & areas around there are getting hit by the dust that kicked up in the Pails yesterday. Pic story & here.

It's even in the NWS forecast in some cities across Georgia and Tennessee.

Knoxville, TN:

Tonight: Areas of blowing dust before 8pm. Mostly cloudy, with a low around 42. Southwest wind 5 to 10 mph.
Member Since: July 6, 2010 Posts: 113 Comments: 32524
539. Skyepony (Mod)
Asheville, NC & areas around there are getting hit by the dust that kicked up in the Plains yesterday. Pic story & here.
Member Since: August 10, 2005 Posts: 192 Comments: 38652
ok thats it for me folks-stay safe out there........
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gee this is like what happened in texas last night.....................650 PM EDT FRI OCT 19 2012

...STRONG THUNDERSTORMS TO AFFECT THE DISTRICT OF COLUMBIA...
ARLINGTON...MONTGOMERY...HARFORD...CARROLL...SOUT HERN BALTIMORE...
NORTHERN BALTIMORE...PRINCE GEORGES...ANNE ARUNDEL...HOWARD...FAIRFAX
AND CALVERT COUNTIES...

AT 649 PM EDT...STRONG THUNDERSTORMS WERE LOCATED ALONG A LINE
EXTENDING FROM 2 MILES NORTHWEST OF PARKTON TO WOODMORE...MOVING EAST
AT 20 MPH.

LOCATIONS IMPACTED INCLUDE MORRELL PARK...LANSDOWNE...DRUID HILLS
PARK...LINTHICUM...BALTIMORE...UNION SQUARE...ROLAND PARK...
PHOENIX...HARWOOD AND DUNKIRK.

WIND GUSTS OF 40 TO 50 MPH AND SMALL HAIL CAN BE EXPECTED WITH THESE
STORMS.

&&

LAT...LON 3958 7609 3948 7607 3929 7629 3930 7630
3938 7633 3931 7632 3923 7638 3919 7644
3922 7652 3914 7642 3902 7638 3888 7650
3862 7650 3871 7723 3872 7723 3972 7673
3972 7623
TIME...MOT...LOC 2249Z 275DEG 24KT 3966 7668 3896 7677

$$

SDG
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TORNADO WARNING
MDC005-025-192330-
/O.NEW.KLWX.TO.W.0044.121019T2252Z-121019T2330Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
652 PM EDT FRI OCT 19 2012

THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A

* TORNADO WARNING FOR...
NORTHWESTERN HARFORD COUNTY IN NORTHERN MARYLAND...
CENTRAL BALTIMORE COUNTY IN NORTHERN MARYLAND...

* UNTIL 730 PM EDT

* AT 651 PM EDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A
TORNADO WAS 7 MILES SOUTHWEST OF JARRETTSVILLE...OR 6 MILES
NORTHEAST OF COCKEYSVILLE...AND WAS MOVING NORTHEAST AT 30 MPH.

* LOCATIONS IMPACTED INCLUDE...
JARRETTSVILLE...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING AND AVOID WINDOWS. IF OUTDOORS OR IN A MOBILE HOME OR
VEHICLE...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

TORNADOES AT NIGHT ARE DIFFICULT TO SEE AND CONFIRM. TAKE COVER NOW.

&&

LAT...LON 3951 7655 3955 7664 3973 7653 3972 7626
TIME...MOT...LOC 2253Z 214DEG 24KT 3955 7655

$$
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folks in the mid'lantic states,heed your local warnings..stay safe up there..weather is turning bad tonight..................COASTAL HAZARD MESSAGE
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
329 PM EDT FRI OCT 19 2012

MDZ014-200330-
/O.NEW.KLWX.CF.Y.0049.121020T0000Z-121020T0400Z/
ANNE ARUNDEL-
329 PM EDT FRI OCT 19 2012

...COASTAL FLOOD ADVISORY IN EFFECT FROM 8 PM THIS EVENING TO
MIDNIGHT EDT TONIGHT...

THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A
COASTAL FLOOD ADVISORY...WHICH IS IN EFFECT FROM 8 PM THIS
EVENING TO MIDNIGHT EDT TONIGHT.

* TIDAL ANOMALY...UP TO ONE FOOT ABOVE ASTRONOMICAL PREDICTION.

* TIMING...AROUND HIGH TIDE THIS EVENING.

* EXPECTED IMPACTS...MINOR COASTAL INUNDATION...PARTICULARLY
AROUND ANNAPOLIS.

HERE IS THE TIME OF THE NEXT HIGH TIDE

ANNAPOLIS U.S. NAVAL ACADEMY...9:34 PM...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A COASTAL FLOOD ADVISORY INDICATES THAT ONSHORE WINDS AND TIDES
WILL COMBINE TO GENERATE FLOODING OF LOW AREAS ALONG THE SHORE.

&&

$$

JACKSON
Member Since: Posts: Comments:
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
645 PM EDT FRI OCT 19 2012

MDC005-192300-
/O.CON.KLWX.TO.W.0043.000000T0000Z-121019T2300Z/
BALTIMORE MD-
645 PM EDT FRI OCT 19 2012

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 700 PM EDT FOR BALTIMORE
COUNTY...

AT 645 PM EDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO
WAS LOCATED NEAR COCKEYSVILLE...AND WAS MOVING NORTHEAST AT 25 MPH.

LOCATIONS IMPACTED INCLUDE...
JACKSONVILLE...
MONKTON...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING AND AVOID WINDOWS. IF OUTDOORS OR IN A MOBILE HOME OR
VEHICLE...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

THIS TORNADO MAY BE WRAPPED IN RAIN AND HARD TO SEE. DO NOT WAIT TO
SEE OR HEAR THE TORNADO. TAKE COVER NOW.

TORNADOES AT NIGHT ARE DIFFICULT TO SEE AND CONFIRM. TAKE COVER NOW.

&&

LAT...LON 3948 7657 3952 7668 3962 7661 3952 7651
TIME...MOT...LOC 2245Z 221DEG 21KT 3952 7661

$$
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That low is sent toward MI at 348hrs.


Doppler ,if you are still here, please stay safe and listen to any warnings as storms a forming.
Member Since: March 16, 2012 Posts: 127 Comments: 7958
Quoting allancalderini:
Will this tropical wave if it develops into something will it move northeast to Cuba or West to Central America?
what the NWS is watching in regards to cuba is a storm development in the southern caribbean then moving notheastward over cuba or therebouts..my guess is the atlantic storm turns NE up towards the bahamas maybe even before getting to the islands..we'll see next week
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I hope Doppler22 is keeping an eye on things because there's a tornado warned storm in MD heading for the PA border.
Member Since: February 11, 2012 Posts: 84 Comments: 7946
While this is far out in time, look at that low over the southern US at 324hrs.
Member Since: March 16, 2012 Posts: 127 Comments: 7958
Will this tropical wave if it develops into something will it move northeast to Cuba or West to Central America?
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Kind of a crazy run... look at the storm in the south by 324 hours:

Member Since: February 11, 2012 Posts: 84 Comments: 7946
Quoting wxchaser97:
And former Sandy gets sent toward the NE at 276hrs.



likey the 1st nor ester
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storm coming to you WPB.............
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looks like ND will be need a all day hard frz warning with highs olny in the mid 30s come mid week next week
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Never mind, that isn't former Sandy. She is taking NE toward the Azores and absorbed.
Member Since: March 16, 2012 Posts: 127 Comments: 7958
Cold completely breaks down by 252 hours:

Member Since: February 11, 2012 Posts: 84 Comments: 7946
to me this is still almost summer huh..................
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228 hours. Cold air weakens some as the TS moves out to sea:

Member Since: February 11, 2012 Posts: 84 Comments: 7946
Cold air is locked in over the Great lakes and the GFS does at split and has 1-2 systems going at 228hrs.
Member Since: March 16, 2012 Posts: 127 Comments: 7958
Quoting KEEPEROFTHEGATE:


check this out might help

Link


Thanks KotG! Sent her the link.
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Quoting MAweatherboy1:
This is a remarkably deep trough being portrayed by the GFS:



Some areas in the plains would be getting snow if this pans out. I wouldn't mind an outbreak of cold air right now.


Quoting NCHurricane2009:

That's interesting...maybe "Sandy" would get swept up ahead of the strong UP system...and end up transforming "Sandy" into a decent nor'easter while taking advantage of the baroclinic zone of the UP system...


So far Sandy isn't moving too much in this run but it could become a nor'easter later in the run, we will see.
Member Since: March 16, 2012 Posts: 127 Comments: 7958
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Quoting TropicalAnalystwx13:

The computer models, with the exception of the CMC, are not excited about developing the Central Atlantic tropical wave. Do you think it has a respecatable chance?


chat!
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Quoting wxchaser97:
1000mb TS at the Bahamas and more cold air spilling in at 174hrs.
yes most of the models put a storm near the bahamas next week
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1000mb TS at the Bahamas and more cold air spilling in at 174hrs.
Member Since: March 16, 2012 Posts: 127 Comments: 7958
This is a remarkably deep trough being portrayed by the GFS:

Member Since: February 11, 2012 Posts: 84 Comments: 7946
Quoting RetiredChiefP:
Alright my weather experts, my wife needs somehelp. We both know a bit about El Niño and La Niña...but she needs a short, yet simple explanation that her students (9th grade Geography) can comprehend. Any suggestions on reference materials?

Thanks,
Chief P...(retired)


check this out might help

Link
Member Since: July 15, 2006 Posts: 175 Comments: 54847
One week out. Cold is plunging into the central US as a weak system moves near the Bahamas:

Member Since: February 11, 2012 Posts: 84 Comments: 7946
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Quoting wxchaser97:
Strong low pressure over the UP providing a rush of cooler air. There is also a TS near the SW Bahamas at 156hrs.

That's interesting...maybe "Sandy" would get swept up ahead of the strong UP system...and end up transforming "Sandy" into a decent nor'easter while taking advantage of the baroclinic zone of the UP system...
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Strong low pressure over the UP providing a rush of cooler air. There is also a TS near the SW Bahamas at 156hrs.
Member Since: March 16, 2012 Posts: 127 Comments: 7958
new GFS at 144 hours....................
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Look at the system in the Midwest at 150 hours:

Member Since: February 11, 2012 Posts: 84 Comments: 7946
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Quoting ncstorm:
12z CMC out to 180 hours
whew if that goes up the east coast..for sure a strong nor'easter,and whew on the size of it too
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Quoting TropicalAnalystwx13:

The computer models, with the exception of the CMC, are not excited about developing the Central Atlantic tropical wave. Do you think it has a respecatable chance?

I am assessing right now...fundamentally I am looking to see if the upper vortex in the central Atlantic is weakening or giving way. If the upper vortex gets out of the way...shear will reduce and we could get something...
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Quoting NCHurricane2009:
Folks...

We may end up with Sandy and Tony this upcoming week in the Atlantic. Unbelievable! I have written a special update talking about this. I have also a more complete discussion I did at 7 AM this morning (see paragraphs P6 and P5 in that complete discussion for info on the 2 areas of interest)....

The computer models, with the exception of the CMC, are not excited about developing the Central Atlantic tropical wave. Do you think it has a respecatable chance?
Member Since: July 6, 2010 Posts: 113 Comments: 32524
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Quoting Doppler22:
Line of storms forming around the DC, Baltimore and York, PA areas.... IM hoping theres lightning :D

Doppler this might be for your area, a new mesoscale discussion but a watch is unlikely.

MD 2079

To everyone, there is a 1003mb low near Hispaniola at 132hrs.


We still won't have a great handle on track and intensity until it develops.
Member Since: March 16, 2012 Posts: 127 Comments: 7958
138 hours:

Member Since: February 11, 2012 Posts: 84 Comments: 7946
Folks...

We may end up with Sandy and Tony this upcoming week in the Atlantic. Unbelievable! I have written a special update talking about this. I have also a more complete discussion I did at 7 AM this morning (see paragraphs P6 and P5 in that complete discussion for info on the 2 areas of interest)....
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Tropical cyclones are occurring more frequently than before
Posted on October 18, 2012


October 18, 2012 – CLIMATE – Are there more tropical cyclones now than in the past? – or is it just something we believe because we now hear more about them through media coverage and are better able detect them with satellites? New research from the Niels Bohr Institute clearly shows that there is an increasing tendency for cyclones when the climate is warmer, as it has been in recent years. The results are published in the scientific journal PNAS. How can you examine the frequency of tropical cyclones throughout history when they have not been systematically registered? Today cyclones are monitored from satellites and you can follow their progress and direction very accurately. But it is only the last approx. 40 years that we have been able to do this. Previously, they used observations from ships and aircraft, but these were not systematic measurements. In order to get a long-term view of the frequency of cyclones, it is necessary to go further back in time and use a uniform reference. Climate scientist Aslak Grinsted of the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen therefore wanted to find some instruments that have stood and registered measurements continuously over a long period of time. “Tropical cyclones typically form out in the Atlantic Ocean and move towards the U.S. East Coast and the Gulf of Mexico. I found that there were monitoring stations along the Eastern Seaboard of the United States where they had recorded the daily tide levels all the way back to 1923. I have looked at every time there was a rapid change in sea level and I could see that there was a close correlation between sudden changes in sea level and historical accounts of tropical storms,” explains Aslak Grinsted. Aslak Grinsted now had a tool to create statistics on the frequency of cyclones that make landfall – all the way back to 1923. He could see that there has been an increasing trend in the number of major storm surges since 1923. –Terra Daily
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18z GFS is running. 120 hours:

Member Since: February 11, 2012 Posts: 84 Comments: 7946
Quoting CybrTeddy:


El Nino is the warming of the ocean at the equator in the Pacific that causes increased trade winds in the Atlantic, and cooler sea surface temperatures in the Atlantic.

La Nina is the cooling of the ocean at the equator in the pacific that causes decreased trade winds in the Atlantic, and warmer sea surface temperatures in the Atlantic.

Also tell her to mention, if the lesson plan brings up Hurricanes, that an El Nino or La Nina event doesn't determine hurricane activity, as this year is a El Nino(ish, but pretty technical stuff there) and it's the 5th most active hurricane season ever. Would be nice if the new generation knew not to get complacent when the news says it's an El Nino year!


Thanks CybrTeddy...succinct, understandable, and I agree with last paragraph...

I knew I could count on the Wunderbloggers!
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NHC discussion at 22:05 UTC of EPAC development that GFS shows. They dont go by GFS for now.



A REGION OF DEEP CONVECTION NEAR THE MONSOON TROUGH BETWEEN 89W
AND 93W HAS A LOW-LEVEL VORTICITY MAXIMUM ASSOCIATED WITH IT. AS
THIS AREA PROGRESSES WESTWARD...THIS SHOULD INDUCE A WEAK
TEHUANTEPEC GAP WIND EVENT COMMENCING EARLY SAT. THE GFS IS THE
MOST AGGRESSIVE MODEL WITH A WEAK LOW DEVELOPING SOUTH OF THE
MEXICO-GUATEMALA BORDER BY SAT MORNING AND INDUCING N TO NE
WINDS UP TO 25 KT. THIS IS MAINTAINED WITHIN THE HIGH SEAS
THOUGH IF THE OTHER MODELS ARE CORRECT IN LESS DEVELOPMENT.

THE AFOREMENTIONED DISTURBANCE IS ROBUSTLY SPUN UP INTO A
TROPICAL CYCLONE BY MON WITHIN THE 12Z GFS S OF SOUTHERN MEXICO
BUT REMAINS SUBSTANTIALLY WEAKER WITHIN THE GFS ENSEMBLE MEAN.
THE REMAINING GLOBAL MODEL GUIDANCE ONLY SHOWS AN E TO W
EXTENDED MONSOON TROUGH THROUGH EARLY NEXT WEEK. THE GRIDDED
FORECAST WILL FAVOR THE MODEL CONSENSUS OF NO DEVELOPMENT AND
DOWNPLAY...AT THIS TIME...ANY TROPICAL DEVELOPMENT. EVEN SO...IT
IS QUITE SHOCKING TO SEE THE GFS DEPICTING A HURRICANE BY WED
AND THE OTHER MODELS SHOWING ALMOST NOTHING.
Member Since: April 29, 2009 Posts: 75 Comments: 14560

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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.