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New Models and Track Posted for Tropical Storm Irene

posted on Sunday, August 21st, 2011 at 3:00 pm

The National Hurricane Center has shifted the track forecast slightly to the right or east of their 10am track. This shift is most likely in response to the continued shift of computer models to the east. While the shift farther northward may allow Irene to strengthen as it would not be impacted as much by Hispaniola and Cuba, it would also steer the storm farther away from Florida. However, this could also pose a greater risk to Georgia and South Carolina, which could suffer a direct hit.

National Hurricane Center Track, Image: NOAA

National Hurricane Center Track, Image: NOAA

Computer Model Tracks, Image:

Computer Model Tracks, Image: Colorado State Track Model Guidance

Dawn Brown, FOX 8 New Orleans

Latest Tropical Storm Irene Track and Model Output

posted on Sunday, August 21st, 2011 at 10:45 am

Latest track from National Hurricane Center. More tracking available from the link on your left.

Irene 5-Day Forecast

Irene 5-Day Forecast

track_early2

Don’t “Tie Yourself to One Model”, Irene Threatens US

posted on Saturday, August 20th, 2011 at 4:39 pm

To track TS Harvey, click here. To track Irene, click here. To track 98L, click here. For an overall look at the tropics, go to MYL’s Hurricane Tracking page.

Tropical Storm Harvey, the 8th storm of the 2011 Hurricane Season, is moving through central Belize tonight. It will likely degenerate over Guatemala and Mexico, but is producing quite a bit of rainfall in and around the center of circulation.

Infrared Satellite, TS Harvey, Image: NOAA

Infrared Satellite, TS Harvey, Image: NOAA

Harvey formed in the central Caribbean and didn’t pose a threat to the United States from its inception. At the same time Harvey or TD 8 was forming, a very unimpressive tropical wave was catching our attention in New Orleans, merely based on the long-range computer models.

The models, mostly notably the GFS, or Global Forecast System, was projecting a major hurricane to form as it approached the Caribbean and making landfall somewhere along the US coastline in the end of August.

In 2006, the GFS predicted a similar occurrence about 10-15 days out.

2006 Hurricane Ernesto, Image: Unisys

2006 Hurricane Ernesto, Image: Unisys

It turned into Hurricane Ernesto, a category 1 hurricane, that weakened substantially over western Haiti and eastern Cuba, before hitting Florida as a tropical storm. The only reason I bring up Hurricane Ernesto is to touch on the current unreliability of long range computer models. And really what I mean by long-range, is past 3 or 4 days. As I state this, the global computer models have improved. Last year, I noticed that the GFS was doing a fairly good job of forecasting the inception of a storm, meaning in 10-15 days, the global computer models could pick up on a closed circulation (or a tropical depression) forming. I emailed an expert the National Hurricane Center about it, and they concurred, that they had made some improvements to the GFS. What the GFS could not do and still has trouble telling us, is how strong this system will be when it arrives. However, there is another global computer model that is being heavily relied on by hurricane forecasters that is doing a fairly good job in telling us which storms will strengthen and where they will go.

National Hurricane Center

National Hurricane Center

Last year, while attending the annual Broadcaster’s Conference of the American Meteorological Society in Miami, attendees were privileged to meet, not only the entire staff of hurricane forecasters from the National Hurricane Center, but we also got every insight they could offer to how they put together the forecast. One of the forecasters/researchers also told us the ECMWF, the forecast put other by the European Centre for Medium Range Weather Forecasts had been beating their track forecast for the past couple of years. The percentage was small, but somehow, their global forecasting model was able to beat forecasters with 20-30 years of experience. This may get some guffaws from readers, but keep in mind that the official track by the National Hurricane Center was statistically better than all of the other computer models out there. That means—don’t tie yourself to one model.

Ever since they told me that, I can’t help it.  I rely on the “European”.

But then, last year, I noticed the GFDL, the United States’ global hurricane model, nailing the forecast track as well. I was hopeful, proud. I’m not sure why, but I guess it bothered me a little bit that Europe, which is barely affected by hurricanes, could forecast them better than us! Then the GFDL started really performing well on the track and intensity.

That was last year. This year, I’m back to the European. I don’t know what happened to the GFS and GFDL, but this hurricane season, it’s been having some wild swings when it comes to storm tracks. It also ratchets some storms into a major hurricanes 10-15 days out like it did back in 2006.  The European only goes out 8 days, but in the last few years, I felt confident telling my viewers which way the storm was headed and relatively how strong the storm was going to be when it got there. This year, it’s been guiding me through Arlene, Bret, Cindy, Don and Emily. It forecast Emily forming briefly, dying somewhere north of Hispaniola and then possibly reforming as a weak system before getting carried northeast with a trough of low pressure off the East Coast. Guess what happened? Exactly that. Now, the GFS did eventually forecast a similar scenario. And, it’s much easier to be confident with a forecast when more of the computer models are in alignment.

And the European only guides me in track and possible strength. It doesn’t give particulars, what’s causing the weakening/strengthening, how weak/strong will the storm be, what areas could suffer torrential downpours or high winds. It’s merely guidance. We still have to do all of our own analysis of the wind shear, upper air pattern, the water vapor (these tropical systems really struggle with dry air), the Saharan Air Layer, everything that tells us what kind of storm we’ll be dealing with. But, it gives me confidence to let me know if I need to be gearing up for a 5-day stretch of spending the night in the weather center. (Technically I got to go home during Gustav—I lived 3 blocks from the station!)

Infrared Satellite, Invest 97L, Image: NOAA

Infrared Satellite, Invest 97L, Image: NOAA

In terms of Invest 97L, it’s been undergoing some interaction with dry air and wind shear that has kept it from developing into Tropical Depression # 9 or Tropical Storm Irene. It looks like it’s going to be a tropical storm in the next 24-hours. It also looks like despite dry air still to its north and west and its possible interaction with Hispaniola and Cuba, it will most likely hit Florida as a tropical storm or possibly even category 1 hurricane.

It looks like the persistent trough off the East Coast will keep it from affecting the northern Gulf Coast states.

I say this in confidence at this point because of my faith in the European. Also-because the other computer models are lining up with a similar forecast.

But… since I live along the Gulf Coast and not along the beaches of the Mediterranean, I still keep my hurricane plan in place until October 15th.

Dawn Brown, FOX 8 New Orleans

P.S. This is my anecdotal account of forecasting with models, Wunderblogger Jeff Masters has a much more studious approach to explaining the performance of models in his blog, click here.

Arlene to Drench Drought Stricken Mexico

posted on Wednesday, June 29th, 2011 at 4:10 pm

The Latin American Herald Tribune is reporting today that Mexico is experiencing its worst drought in 70 years.

Tropical Storm Arlene may alleviate some of the drought, although many mountainous regions may experience flash floods because of the amount of rainfall associated with the tropical storm.

Tropical Storm Arlene, Image: NOAA

Tropical Storm Arlene, Image: NOAA

The satellite presentation became much more impressive in the overnight hours, most likely due to the lack of wind shear in the southwestern Gulf of Mexico. Thunderstorms started sprouting up in the southern and eastern section of the storm early this morning. It’s possible Arlene could reach just below hurricane strength before making landfall between Tampico and Poza Rico. The topography in this section of Mexico makes it susceptible to flooding rains.

Although Arlene doesn’t have much time to strengthen, it could be just below hurricane strength before making landfall between Tampico and Poza Rica. For complete tropical storm coverage, visit TV stations in coastal towns of Texas like Houston and Corpus Christi.

Dawn Brown, FOX 8 New Orleans

Weak Tropical Storm Arlene on Track for Mexico

posted on Tuesday, June 28th, 2011 at 7:14 pm
Tropical Storm Arlene, Image: NOAA

Tropical Storm Arlene, Image: NOAA

The National Hurricane Center began issuing advisories on Tropical Storm Arlene at 7pm Central Daylight Time this Tuesday, June 28th. The storm’s satellite presentation isn’t all that impressive, but it’s kicking up some good wave heights in the central Gulf of Mexico (up to 12′). The area of showers and thunderstorms west of the Yucatan Peninsula has been fairly persistent over the last few days and observations near the center of the storms show maximum sustained winds of about 40 miles per hour.

Arlene is expected to make landfall just south of Tampico, Mexico sometime on Thursday. It could provide some heavy rainfall for Tampico, Ciudad Valle and San Luis de La Paz Mexico. This is a mountainous region of central Mexico and tropical storms can dump copious amounts of rain over this region.

For the latest statistics on Arlene, go to the National Hurricane Center website. This is expected to be a fairly active hurricane season.

Dawn Brown, FOX 8 New Orleans

Ski ’til July 4th! Watch Yosemite Fall!

posted on Wednesday, June 22nd, 2011 at 9:28 pm

Reporting on the record snowfall across the western United States convinced me to plan a last minute trip to Mammoth Mountain Ski Resort in early June. I recruited my husband, fellow meteorologist Jonathan Myers, to venture west with me, to take advantage of the late season snow! We ended up flying into San Francisco, (where my sister lives), and had to drive the looooong way around to get to Mammoth because all of the Sierra Nevada mountain passes were closed (due to the record snow). You know how something that seems likes it’s going to be a huge hassle turns out to be a big blessing? That’s the way our trip went. My Mom convinced us to go to Yosemite National Park to see how the record snowfall and melt had enhanced the waterfalls in the park. Yosemite is not that far from San Francisco-about 4-5 hours. We booked a tent/cabin in Camp Curry and drove over.

Camp Curry, Yosemite National Park

Camp Curry, Yosemite National Park

This is a picture of our cabin/tent. They have heated cabins, but since we booked at the last minute, we bundled up with wools blankets and sleeping bags with overnight temperatures in the 30s.  At about 4am, I started asking if we could just get up and go hiking since I was freezing. Everybody finally got up at about 5:15am and we were on the trail to Vernal Falls by 6.

Vernal Falls, Yosemite National Park

Vernal Falls, Yosemite National Park

The hike to Vernal Falls is only about 3 miles round trip. In fact, by 6:40, we only had .3 miles until we got to the top. That’s about 17-18 hundred feet, right? My Mom and I had a little optimistic mid-hike meeting, saying we should go on to Nevada Falls, which is 5-6 miles round trip since we were making such good time. Yeah, no. The last .3 miles is straight up, stairs, with a mist coming off the falls that soaks you from head to foot. You’d be shivering if you weren’t sweating so much from the hike.  Don’t get me wrong. It was beautiful, inspiring, something I’m so glad we did. But, it was not an easy 1.6 mile hike. We did continue about a 1/2 mile more to get this beautiful sunrise shot of Nevada Falls.

Nevada Falls Sunrise, Yosemite National Park

Nevada Falls Sunrise, Yosemite National Park

If I were to do Vernal Falls and/or Nevada Falls again, I would recommend carrying a poncho, water, and snacks! A peanut butter and jelly sandwich with a little coffee would have tasted so good as we watched this sunrise! We were very happy that we got on the trail so early. When we were hiking downhill at 8am, there was a line of summer hikers headed up. It’s punishing to get up before the sun comes up to hike, but it’s worth it when there’s nobody on the trail and you get the sunrise views.

Later, we drove around and looked at some of the other waterfalls, including the famous Yosemite Falls which is the tallest waterfall in the United States. The snowfall over the Sierra this year is 178% of normal, and the output from Yosemite Falls at the time of this picture was 1600 cubic feet per second. It was beautiful.

Yosemite Falls, Yosemite National Park

Yosemite Falls, Yosemite National Park

When we left Yosemite, we had to head back toward the west, then north and then east again because the mountain pass east from Yosemite was closed. If Tioga Pass (Highway 120) had been open, it would have taken us 2-3 hours to get to Mammoth. Instead, it took about 10 hours!!! Thank goodness the views were amazing. As I’m writing this, I’m disappointed we didn’t capture the shot as we rounded the bend on U.S. Highway 50 into South Lake Tahoe and saw the incredible view of the lake, the glacier mountains and the valley floor. It was a very steep mountain pass and there was nowhere to pull over!

As we drove toward South Lake Tahoe, we saw a roadside construction sign that said Monitor Pass was open, so we headed over Highway 89 toward US 395 that would take us into Mammoth. Highway 89 is a remote highway that takes you through Markleeville, California.  More windy roads without guard rails, more incredible, once-in-a-lifetime vistas. There is a bike ride that goes over these mountain passes in the summertime called the Death Ride.

We spent two days in Mammoth. Spring skiing is always a good trip because there are less people on the mountain and it’s warmer. The ski conditions were also remarkable for the time of year. The mountain is open daily until July 4th.

On the way back, we found out Caltrans had just cleared Highway 108 or Sonora Pass. A long and windy trail over the Sierra Nevada Mountain range, it passes US military training camps and freshwater rivers filled with recent snowmelt. The top of the pass still had 10-15′ of snow. Incredible.

Sonora Pass, 9,582'

Sonora Pass, 9,624'

We ran into a German couple right by this sign, we had both stopped to get pictures of the snow. Luckily, we made it to this sign just before darkness fell. It was still a long drive to the bottom of the mountain and the lights of the interstate.

Dawn Brown, FOX 8 New Orleans

2011 Hurricane Season Begins

posted on Wednesday, June 1st, 2011 at 7:49 pm

The National Hurricane Center is currently watching two areas in the Atlantic for the possibility of development into a tropical system.

Gulf of Mexico Disturbance, IR Imagery, NOAA

Gulf of Mexico Disturbance, IR Imagery, NOAA

The infrared image above shows the area of showers and thunderstorms from the system in the Gulf of Mexico. A line of heavy thunderstorms rolled through Tampa earlier today associated with that disturbance. Both have a 10% chance for development.  There is the possibility this area of showers and thunderstorms could strengthen over the central Gulf of Mexico before quickly weakening because of the amount of wind shear in the western Gulf.

Wind Shear, Gulf of Mexico

Wind Shear, Gulf of Mexico, Image: University of Wisconsin

The GFS or global forecast system model (which has its own Facebook page) has been developing the area of disturbed weather in the Caribbean Sea since the beginning of the week.

Last year, the GFS did a fairly good job of showing areas of possible development at the far end of the forecast cycle. For example, the GFS model run goes out 15 days in the future. Last year, most of the systems it showed developing at the end of that 15 day cycle did develop. However, not all of them developed into a tropical storm or hurricane as the model predicted. It used to be that we could discount a tropical storm that developed at the end of the model run because it just wasn’t accurate. That’s not the case anymore. It may be there, but we still don’t know what kind of storm we’ll be dealing with.

Back to today! The active weather pattern continues across the US. Springfield, Massachusetts got hit with a tornado today. And Kansas has more storms rolling through tonight.

Dr. William Gray and Phillip Klotzbach came out with their latest hurricane forecast today. No changes from their April forecast update. Gray/Klotzbach are still forecasting 16 named storms, 9 of those to become hurricanes and 5 major hurricanes. Klotzbach and forecasters with the National Hurricane Center point to above average sea surface temperatures in the Atlantic Ocean; a La Nina or neutral La Nina, which leads to low wind shear across the Atlantic Ocean; and a multidecadel cycle of active hurricane seasons.

I’ll be back tomorrow with an update on these disturbances being watched by the National Hurricane Center. Go to my Hurricane Tracking page to follow the latest storms.

Dawn Brown, FOX 8 News, New Orleans, dbrown@fox8live.com

Solar Flares Ignite Worldwide Sun Watch

posted on Thursday, February 17th, 2011 at 7:35 pm

The National Weather Service, Space Weather Prediction Center, is reporting a solar blast occurred this week, “…prompting a rerouting of air traffic and causing disruptions to high frequency communications.” (National Weather Service) The solar flare is already disrupting radio communications in China. NASA is concerned it could disrupt electrical power grids and satellites used on Earth tonight through Saturday, February 19th.

According to NASA, “On Valentine’s Day the Sun unleashed one of its most powerful explosions, an X-class flare. The blast… was also accompanied by a coronal mass ejection, a massive cloud of charged particles traveling outward at nearly… (sic)  600 miles per second.”  Tonight some of energy from the sun could pass through the earth’s atmosphere and put on a light show for the northern and southern hemispheres. The charged particles excite the oxygen and nitrogen atoms in the earth’s atmosphere, making them glow blue, red, green, or magenta. Chances are most of us won’t see it, but my cousin up in Minneapolis might be lucky enough to see the spectacular display of light!

Solar X-Ray, GOES Satellite

Solar X-Ray, GOES Satellite

Check out this latest solar x-ray image from the GOES 15 satellite program. According to NOAA, or the National Oceanic and Atmospheric Administration, the latest GOES spacecraft carry a solar x-ray imager to monitor the sun for early detection of solar flares and other solar events that impact the earth. It’s an early warning program to try and protect astronauts during space missions, and also military and commercial satellite communications.

Solar Flare 2011

A solar flare in 1989 caused a major blackout in Canada. Concern over the impact of this week’s event have caused air travel to be rerouted

For a current list of solar flare rankings, click here. (This one isn’t at the top of NOAA’s list.) For the latest images from NOAA’s solar x-ray, click  here.

Besides the excitement from the solar flares, the other exciting weather news today was the winter storm warnings for the Sierra. Check out the latest forecasts for Sacramento, Reno.

Biggest Solar Flares in 4 Years Heading Toward Earth

Frame from an animated GIF showing the solar flare in question. [Photo: NASA/Solar Dynamics Observatory]That big massive ball of burning hydrogen in the center of our solar system has been getting more and more active as of late–the sun recently had three solar flares explode from the corona, its high temperature plasma atmosphere. Particularly powerful solar flares produce coronal mass ejections, which can reach temperatures of millions of degrees Fahrenheit at the time of explosion and can eventually reach Earth.

We’re lucky to live on this planet: This round, sweet Earth has a magnetic field that protects us terrestrial inhabitants from a good deal of space weather, including high radiation-charged particles emitted from the Sun during these coronal mass ejections (CMEs). That said, these latest three solar flares were the largest in the last four years, and should put on a spectacular light show when they reach us tonight and on Friday. These flares also mark the ramping up of a new solar cycle, which means we should be seeing more and more solar flares in the next few years.

Most of these charged particles are deflected or trapped by Earth’s magnetic field, but some make it through to our atmosphere and excite the oxygen and nitrogen atoms, making them glow blue, red, green, or magenta, producing the spectacular aurora we can see in northern or southern latitudes (sorry, folks at the equator). These recent solar flares should make for some spectacular aurorae tonight

Here Comes The Fog Again

posted on Tuesday, February 15th, 2011 at 10:03 pm

After an unusually cold and dry winter so far across the Gulf South, the pattern has taken a more typical turn.  High pressure is building back in, winds out of the southeast are setting up, and warmer temperatures are ushering back in, but also so is dense overnight fog.  As the pattern stagnates over the next several days, reduced morning visibilities can be expected across portions  of the Gulf states.  In fact Dense Fog Advisories have been issued for the coast of Southeast Louisiana for visibilities below 1/4 mile at times.  Cities that can expect slow morning commutes are places like New Orleans, Baton Rouge, and Biloxi.

Dense Fog Advisory February 15, 2011, Image: NOAA

Dense Fog Advisory February 15, 2011, Image: NOAA

What’s the deal with this Gulf Coast fog during the Fall, Winter, and Spring?  Well, its something called sea fog and it doesn’t just happen in Louisiana and Mississippi.  In fact, it also occurs in other places in the United States, like San Francisco, and even in other places around the world, like Hong Kong!

Sea Fog Formation, Image: Hong Kong Observatory

Sea Fog Formation, Image: Hong Kong Observatory

Take a look at the image above.  This is what causes sea fog to form.  Winds from a warm and humid source region blow over an area of colder water.  This helps to condense the moisture out of the warm, moist winds as they pass.  This process forms a low cloud.  Those same winds then push the newly-formed cloud over a nearby landmass and voila: fog.

In the case of the Gulf South, these winds are southeasterly and pick up warmth and moisture from the Central Gulf of Mexico, where the deep waters still have temperatures well into the 70s.  These rather tropical winds then run northwestward over shallower near-shore waters, that are much more subject to cooling by the cold wintertime land temperatures.  These coastal waters have temperatures only in the 50s.  This helps condense the moisture out of the warm, relatively muggy southeasterly winds.  Hence, a bank of low clouds forms.  The southeasterly winds then push that batch of clouds onshore and there you have it: sea fog and rough morning commutes across the Central Gulf states this week.

Pretty “Cool” Ice Photos & Its “Effect” On Lake-Effect Snow

posted on Sunday, February 13th, 2011 at 8:19 pm

Think this winter’s been bad in the South?  Well imagine over 100 inches of snow… every year!  Places like the Great Lakes see it, routinely. You know when you hear about those Christmas or New Year’s reports of 35 inches of snow snarling holiday travel in places like Buffalo, New York?  Well, typically that’s caused by a phenomenon known as lake-effect snow.  Lake-effect snow is caused by an unstable atmosphere (similar to the atmosphere during a thunderstorm.)  In the case of thunderstorms, you have an atmosphere with lots of humidity, warm ground, and a cool upper atmosphere.  Lake-effect snow is caused by cold, arctic air rushing in on cold winds out of the northwest over the relatively warmer (and of course, moist) Great Lakes waters.  Now, of course, you need “water” to get lake-effect snow going.  If there’s ice covering the lake, the water vapor needed for lake-effect snow is not available and the lake basically “shuts down” for the production of lake-effect snow.

The Great Lakes, as you may  know, are very big: hundreds of miles long, tens of miles wide, and hundreds of feet deep, so it’s not likely they’ll all entirely freeze over for any significant amount of time, although it is, on rare occasion, possible that they’ll mostly freeze over, like during the very cold winters of 1976-1977, 1977-1978, and 1978-1979.  Most years, though, most locales on the lakes don’t get a break and get inundated with lake snow all winter long.

In several areas, though: far western New York, northwestern Pennsylvania, and northern Ohio, folks do get a break!  During the coldest months of the winter; it’s typical during many winters, the shallowest of all the lakes, Lake Erie, will nearly entirely freeze over and this nearly closes down the heavy snow machine along its shoreline.

February 8, 2011 Lake Erie Ice Cover, Image: NOAA

February 8, 2011 Lake Erie Ice Cover, Image: NOAA

In the latest February image of Lake Erie taken via satellite above, you can see  there’s lots of white over the lake.  That’s actually a sheet of ice.  The darker black area, in fact, is the area of the lake that has been left uncovered and unfrozen. By far, there’s more ice than water.   Therefore, it’s tough to get much more than lake-effect flurries going.  Earlier in the season, though, before it really gets cold, it’s a totally different story.

January 11, 2011 Lake Erie Ice Cover, Image: NOAA

January 11, 2011 Lake Erie Ice Cover, Image: NOAA

In the satellite photo above, you can see just a month ago, before the long duration of cold… the lake is wide open with plenty of water and water vapor to work with!  This is the season where we see the blizzards along the lake shore.

To check out the forecast in places affected by the lake  freeze-over lull, take a look at Cleveland and Buffalo.

On a side note, take a look at the imagery again and focus on the upper right.  That’s Lake Ontario.  It’s over 10 times deeper than Lake Erie.  You can see, between both photos, there’s not much change in the amount of white on the lake.  Lake Ontario, since its much deeper and contains a larger volume of water, has a much harder time cooling off and, therefore, has a much harder time freezing.  In places like Rochester and Watertown, New York, there’s nary a respite from the lake snow onslaught.

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