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Hurricane Threat for Gulf of Mexico

November 4, 2009 by pyeager

Tropical Storm Ida is currently in the western Caribbean, and it’s not out of the question that the late-season storm will become a late-season hurricane for the Gulf of Mexico in the coming days.

Hurricane formation in November is rare, but it’s certainly not unheard of, and the National Hurricane Center 5-day forecast cone (as of Wednesday evening) tracks the storm northward toward the Gulf of Mexico.

ida_projected_path

NHC projected path of Tropical Storm Ida

Energy Available for Potential Development

While the storm is forecast to be no stronger than tropical storm strength during this time period, the potential heat of the water in this region leads to the possibility of further strengthening. The following image is courtesy of the Atlantic Oceanic and Meteorological Laboratory (AOML).

gulf_heat_potential_november

AMOL map showing tropical heat potential in Gulf of Mexico and Caribbean

Sea Surface Temperatures

While sea surface temperatures are often a limiting factor for development at this time of year, the following map from AOML indicates that current sea surface temperatures are generally warm enough in the Gulf of Mexico for development, or at least for the maintenance of an existing storm.

A temperature of 26 degrees Celsius is generally considered the lowest temperature to promote hurricane formation.

sea_surface_temps

Gulf of Mexico sea surface temperatures--image from AOML

Tropical Storm Ida is a long way from being a hurricane, and it’s a long way from affecting the United States; however, it warrants being monitored over the next several days.

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Weather and the World Series

November 2, 2009 by pyeager

With teams from New York, Pennsylvania, and Colorado having made the Major League Baseball playoffs this year, the weather has been a factor, with rain and even snow for various games; however, even dry and cold weather affects the flight of a baseball.

Cold, Dry Air is Heavier

While it’s always popular to blame the “heavy” air of the summer for limiting the number of home runs, it’s actually the cold, dry air of fall that negatively affects the flight of a baseball.

Hot, humid air feels heavier to us since our sweat doesn’t evaporate, leaving us feeling sweaty and sticky; however, the hot, humid air of summer is considerably lighter than the cool (or cold) and dry (it terms of absolute humidity) air of the fall.

It might be harder to hit a baseball when it’s cold since our muscles are more likely to be tight, and the impact of the baseball with the bat is more jolting in the cold. In addition to those problems, once the ball has been hit, it will not fly as far it would when it’s warm and dry.

Plenty of Home Runs This Year

Having made those statements–that it’s tougher to hit the ball, and the ball will not fly as far–it might seem surprising that there have been so many home runs this year’s “November Classic.” (The World Series in nicknamed the “October Classic,” but look at the calendar.)

Both the Yankees and the Phillies, the World Series combatants, have enough pure home run hitters that home runs will be common no matter the weather, but it’s also the ballparks.

New, Smaller Yankee Stadium

The brand new Yankee stadium, which is in its first season, has the same dimensions as the old Yankee Stadium; however, some of the outfield walls are two feet lower than the old stadium. In addition, the way the outfield is configured is slightly different, so despite the identical dimensions, there are areas where the fence is a full nine feet closer to home plate. The result has been more home runs.

Citizen’s Bank Park

The home stadium of the Phillies, Citizen’s Bank Park, has dimensions more appropriate for a minor league team than a major league team with a payroll in excess of $130 million. The deepest part of the park is 401 feet, but it diminishes to just 330 feet down the left field line and 329 feet down the right field line.

Yankee Stadium is about 10 feet deeper in center field and 30 feet deeper in left-center field.

Just as a point of comparison, the old Polo Grounds, which had shorter distances down the lines, was a much larger park elsewhere, with a center field dimension of 458 feet, with left-center and right-center dimension of nearly 450 feet.

When you see modern players hitting balls into the stands that look like they should have been innocent fly ball outs, it’s because they would have been innocent fly outs in stadiums of the past.

What is a Phillie anyway?

–Paul Yeager

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Bewitching Weather

October 31, 2009 by pyeager

Since it’s Halloween, here are a few quick Halloween-related weather stories–from this year and previous years.

Snow–Just in Time for Halloween

The first one is not directly related to Halloween, but it’s current. The snowstorm in the Rockies this week, which I talked about a few days ago (Massive Winter-Like Storm) produced incredible snowfall amounts–just in time for Halloween.

Check out Steve’s post on wxtalk.wordpress.com for some great pictures and details (Pictures from Western Winter Storm), including this one from Colorado Livin’:

wx-talk_snow_image

Colorado snowfall in October 2009--image courtesy of Colorado Livin'

The “Perfect” Storm

The so-called perfect storm (information about its lack of perfection is included in Weather Whys) is also sometimes called the “Halloween Storm” since it occurred in late October (1991).

Here’s a link to AccuWeather.com video that highlights the storm: Weather History.

Halloween Blizzard of 1991

Indirectly related to the Perfect Storm was the Halloween Blizzard of 1991, in which tremendous snowfall occurred in the Midwest and northern Plains. Nearly three feet of snow accumulated in some areas (see map below).

halloween_blizzard

Snowfall from 1991 Halloween blizzard

The CIMSS Satellite blog recently posted a loop that shows the snow as it melted (Halloween Blizzard of 1991).

Halloween Flood

A record-breaking flood occurred in Wichita, Kansas, around Halloween (it was a multi-day event, including October 31) of 1998. The local weather service has an account of the storm (Halloween Flood of ‘98), including this image showing cumulative rainfall totals:

halloween98_radar

NOAA image showing rainfall totals from Halloween Flood of 1998

Flooding This Halloween

Unfortunately, flooding is a serious threat this Halloween as well, with watching and warnings extending from Illinois and eastern Iowa southward to eastern Texas and Louisiana.

warnings_oct31_2009

NOAA watching and warnings on October 31, 2009 (12:30 a.m.)

Erik at MemphisWeather.net has the analysis of the weather situation for western Tennessee in his blog.

–Paul Yeager

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Are Storms Most Important Thing to Chasers?

October 30, 2009 by pyeager

Since we’re in the second severe weather season, perhaps it’s appropriate that I talk about storm chasers for a second time. If you read my earlier post (Storm Chasers–Scientists or Thrill Seekers), you might not be surprised to hear me question the motives of storm chasers.

Competition or Science?

While I watch some shows because of the weather (Deadliest Catch–Weather Fish Tales), I usually don’t watch storm-chasing shows, such as TLC’s Storm Chasers. I did see much of the “Bigger in Texas” episode this week, however.

Perhaps it was just the way the show was edited, but it seems as if beating the other storm chaser was as important (or more important) than the supposed science of storm chasing. Editing makes the show. It takes countless hours on the Plains to produce an hour of action for storm chasers. For instance, storm chaser Sean Casey has been chasing for nine years because he wants to make a movie about tornadoes; if it’s for one film (I’m not sure that it is), then there has been plenty of days with no storms, plenty of failed chases, and countless hours of wasted time on the road; otherwise, there would certainly be a movie by now. Storm chasing is much more boring than is indicated by the show.

Regardless of the editing, there was whining about how the other person was “dominating” and whining about how one person imitated another’s vehicle. There was concern about what the other person was doing. It might all have been simple jealousy since some chasers are better than others, but it set a tone of competition, not science.

That might make for better television; in fact, at the end of each episode, perhaps one storm chaser should be voted off the Plains (Joe, You’re storms have dissipated; please pack your radars and return to Seattle), but it’s not a great show for people more interested in the weather than hype.

–Paul Yeager

Posted in Opinion, Pop Culture, extreme weather | Tagged , , , , , , | 4 Comments »

California Dust Storms–Global Warming?

October 28, 2009 by pyeager

The storm that I mentioned yesterday (Massive Winter-Like Storm) has produced quite a bit of wind in California during the past couple of days, resulting in reports of blowing dust (Blowing Dust Prompts Health Warnings and Windy Storms Whips Up Dust Out West…). The question that always follows a dust storm is whether it’s tied to global warming.

Human Processes

California is an area where human processes, such as diverting water from natural paths and converting large areas into farms, leads to the possibility of more dust. Dry lake beds due to irrigation and large swaths of cultivated ground are obviously not a reflection of global warming.

Current Drought

California is also in a multi-year period with less rainfall than normal, and whether the drought is attributable to global warming is a more debatable point. Since this is a blog, not a news story, I feel that I can share my opinion.

Normal Variable of Weather

The current drought and associated dust storms are not enough proof to me that global warming is affecting the weather. California is a naturally dry location, and extended periods of drought, often much more severe than the current one, are common–and have been for centuries. What’s been going on for the past several years falls clearly in the range of normal weather for the region, not an aberration that needs to be explained by larger factors, such as global warming.

I’m not a climate expert, and I’m not a global warming denier; however, I’m a meteorologist who has seen this time of extended dry period in California often enough to know that it does not need to be explained by anything other the normal variation of weather.

Dust Storm Video

By the way, the California Academy of Sciences recently filed a video report about the prospects of dust storms in California (Dust Storms and Climate Change). It was filed after the recent major dust storm in Sydney, Australia.

–Paul Yeager

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Massive Winter-Like Storm

October 27, 2009 by pyeager

Even though it’s still autumn, a major storm system will result in a wide array of intense winter-like weather to the western part of the country during the next couple of days. Winter storm warnings and watches are in effect for parts of the Rockies, where greater than two feet of snow will accumulate in the higher elevations, and high wind watches and warnings extend as far westward as California. 

Sometimes pictures are better than words, so here is a National Oceanic and Atmospheric Administration (NOAA) map showing the watches and warnings as of early Tuesday:

warnings_oct_27

NOAA map of weather watches and warnings on October 27, 2009

While our inclination might be to believe that it’s too early for storms like this, it’s not. The Rockies are notorious for heavy snow in spring and fall, including October and April, and this is something that I highlighted in Weather Whys.

During the winter, the jet stream, which is the fastest layer of wind in the upper levels of the atmosphere that pushes storms along, is often too strong for storms to linger; that’s not the case during the fall in spring, and the result is often a slow-moving storm that lasts for a couple of days, brings intense weather from the West Coast to the Plains, and turns Halloween into a bright, white holiday in the Rockies.

NOTE: This storm is likely to produce widespread intense thunderstorms in the Plains this week–a classic example of the second severe weather season that I talked about last week.

–Paul Yeager

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Fall Foliage Update

October 26, 2009 by pyeager

People often ask me how the weather affects fall foliage, so I thought I’d share a few observations of what makes for the best fall displays.

Obvious Factors Influencing Foliage

We all know that some types of weather, such as snowfall when leaves are in color, major wind storms when leaves are in color, or even heavy rain when leaves are near peak, will damage fall displays.

It is worth noting, however, that foliage still has a chance to be exceptional if these events do not occur when leaves are near peak. For instance, snow that occurred in my area this fall (Autumn in Central Pennsylvania) occurred before peak colors developed–early enough that it doesn’t seem to have had a tremendous dampening of the colors. The early snow certainly did tremendous damage to the trees, but the colors of the leaves seem to have been not affected.

Stress-Free Trees

The key to brilliant color in the determined during the spring and summer months since certain conditions will cause stress in trees. Stressful weather includes drought and too much intense heat, so the best fall color occurs during years when there has been an abundance of spring and summer rain, without too many periods of intense heat or drought.

Perfect Fall Weather

We all have our opinions about what is perfect fall weather, and so do trees, at least in terms of maximizing fall color. The best weather includes generally dry weather, sunny and warm days, and cool nights; however, excessive fall warmth will dull colors, and hard freezes will result in early leaf loss, so it’s a fine line. Some rain in the fall, especially early on, can help to salvage a potentially poor fall season if the summer had been hot and dry.

What’s Fall Foliage Like in My Area?

Here are a couple of links to fall foliage sites:

–Paul Yeager

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Are Pacific Hurricanes Foretelling Upcoming Winter?

October 24, 2009 by pyeager

Is the recent tropical activity in the Pacific an indication of a strengthening El Nino? This is a very important weather question.

The key to the weather across the United States in the upcoming winter is the strength and duration of the current El Nino. In fact, some of the winter 2009-2010 forecasts are based, at least in some degree on the El Nino, and I’ve recently written that the lack of strengthening of the El Nino (El Nino Weak–What Does it Mean?) means that these forecasts are in jeopardy.

I might have spoken too soon.

Central Pacific Hurricane

Hurricane Rick, which occurred during the middle of the month, was the second strongest hurricane in the Pacific basin, but it occurred in the eastern Pacific, away from the center of the El Nino. The activity in the central Pacific (closer to Hawaii) is what might be an indication of warming water in the El Nino zone.

This satellite image from the Central Pacific Hurricane Center (linked above) is an indication of recent activity.

Central Pacific Hurricane Center satellite image from October 23, 2009

Central Pacific Hurricane Center satellite image from October 23, 2009

Hurricane Neki formed to the south of Hawaii and moved northward over the past couple of days, bypassing Hawaii to the west (unlike the devastating Hurricane Iniki in 1992, which occurred during an El Nino). As of Friday afternoon, there was a cluster of thunderstorms to the southeast of Hawaii as well–an area of disturbed weather that will need to be monitored.

Hurricanes are driven by warm water, and if the recent activity is an indication of warming water in this region, then the El Nino might finally be showing the strengthening needed to influence the weather across the United States this winter.

I’ll have an update on El Nino in early November.

–Paul Yeager

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Weather Channel Movies/Waking Up with Al

October 23, 2009 by pyeager

The Weather Channel, one of the first networks to have created truly specialized coverage on cable (a revolutionary concept), is continuing on its move toward less specialized coverage with the announcement that it will soon carry Friday night (weather-themed) movies (Forecast for Movies on Weather Channel).

Not privy to the inner circle of the Weather Channel (parent of weather.com, by far and away the most popular Internet weather provider), I have no idea what the business reasoning for this type of programming change is, but it doesn’t sound like the whole 24-hour-per-day weather coverage business is what it used to be. (Note: In a future post, I will talk about the changing market for the Weather Channel.)

Sleep Until at Least 7 a.m.

I have my doubts that running previously aired (special encore presentation) movies will solve all of their problems, but if it means that there will be fewer commercials about “Waking up with Al,” then I completely support it. Seriously, has there ever been a more annoying set of commercials?

We know. Al Roker is now on the Weather Channel from 6 a.m. to 7 a.m. We know that NBC owns the Weather Channel because every single actor/entertainer/news person makes the same joke about “waking up with Al” in a nearly endless loop of self-promoting commercials. We know. We know. We know.

Most of us don’t care…but we know.

–Paul Yeager

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El Nino Still Weak–What Does it Mean?

October 22, 2009 by pyeager

The latest discussion from NOAA (National Oceanic and Atmospheric Administration) indicates that the El Nino remains weak (ENSO Diagnostic Discussion) as of early October. While that may (or may not) be of interest on its own, what’s more important is what implication the strength of the El Nino has on the upcoming weather across the United States. (It’s an important factor globally, but this blog focuses on U.S. weather).

The uncertainty of the ultimate strength of the El Nino means that the accuracy of winter forecasts based on the El Nino must be read with caution.

El Nino Forecast to Strengthen, But…

The computer models are currently forecasting that the weak El Nino will strengthen–becoming either a moderate or perhaps a strong El Nino.

Computer model projections of strength of El Nino (image courtesy of Climate Prediction Center)

Computer model projections of strength of El Nino (image courtesy of Climate Prediction Center)

However, these very computer models, including the government’s Climate Forecast System (CFS) model, have been too aggressive in predicting the strength of the El Nino so far this year. This was noted in the October ENSO discussion as well and is indicated by the next image:

National Center for Environmental Protection's CFS (Climate Forecast System) model, indicating the over-prediction of the strength of the El Nino

National Center for Environmental Protection's CFS (Climate Forecast System) model, indicating the over-prediction of the strength of the El Nino

Winter Forecast Accuracy

I’m not one to criticize anyone who makes a long-range forecast because they’re so quickly dismissed, require tremendous amount of skill (if done properly), and most important, I don’t make any; however, we have to look objectively at the forecasts. If the El Nino does not strengthen to a moderate level, does that put the accuracy of the forecasts at risk?

A strong El Nino produces a more active southern branch of the jet stream, which is why so many of the winter forecasts (such as NOAA Winter Outlook and AccuWeather Winter 2009-2010 Winter Forecast) are predicting more precipitation than normal across the southern tier of the country. If the El Nino never becomes strong enough to produce that effect, then the forecasts are in jeopardy.

AccuWeather.com (AccuWeather Winter Forecast), to be fair, never forecast a strong El Nino to occur (and bases the forecast on other factors as well–the discussion of which is generally relegated to premium customers); however, their forecast is based, at least in part, on the weakening of a moderate El Nino during the winter, resulting in more snow-producing storms along the Eastern Seaboard. What if the El Nino never strengthens to a moderate level to begin with? Will southern moisture and storms not be available for the northern branch to merge with?

Now that it’s October (and some people have already had accumulating snow!), we’ll know soon enough–and I’ll make sure to look at the strength of El Nino next month.

–Paul Yeager

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