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All posts for the month October, 2012

Sandy from the cloud tops

Posted by Amanda Terborg on 10/31/2012
Posted in: Uncategorized. Leave a comment

Yesterday I asked one of my forecasters if they were especially busy out on the floor given Sandy’s progress through the Northeast. He began to say yes, but then paused, laughed, and said instead, “Not really. I mean, there’s nobody flying out there right now.” His statement was quite true, as yesterday at 4 pm, the number of cancelled flights had grown to more than 19,500, with more expected as the NY area airports are still expecting limited operations. LGA in particular will remain closed until further notice due to flooding and damage on the tarmac and runways. The photo below (courtesy of CBS News) captured the standing water at the airport yesterday afternoon.

121030 Aerial view of flooding at LaGuardia (courtesy of CBS News)

As the afternoon was oddly quiet here yesterday, I took the chance to view Sandy through some of the GOES-R products at my disposal. Below is a loop of ACHA Cloud Top Heights from 121029 1745 UTC – 121030 0755 UTC (click for animation), in which the transition of Sandy from tropical to post-tropical can easily be seen. Tropical characteristics, a more banded appearance shown by the higher cloud tops (blue shades) wrapped around the eye of the storm, slowly transitioned into the more comma-like shape of a post-tropical system and more uniform cloud top heights (green shades) as the dry stratospheric air was wrapped in.

121029 1745 UTC – 121030 0755 UTC ACHA Cloud Top Heights

Watching from afar: Sandy quiets our airspace

Posted by Amanda Terborg on 10/29/2012
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With all the excitement over Sandy ramping up, the National Airspace System on the East Coast has become oddly quiet. With this large storm slowly making landfall, air traffic within the New England area is eerily quiet, with all three NY area airports (LGA, JFK, and EWR), as well as DCA, BWI, and PHL grounding in and outbound air traffic until at least early Tuesday. BOS may join this list later today, and other airports further from the storm, such as ATL, have already implemented ground delay programs as well.

Shown in the graphics below are loops of visible satellite imagery overlaid with ASDI flight routes yesterday morning when operations were still running normally overall (top) compared with flight routes this morning (bottom). Note the significant amount of empty airspace within the Golden Triangle, an area in which air traffic is typically the busiest in the country. Thus far, the current number is upwards of 13,500 flights cancelled, the majority of which are due to Sandy. Estimating 100 people per plane, that is 1,350,000 passengers affected!

121028 1310 -1615 UTC visible imagery and ASDI flight routes

121029 1310 – 1615 UTC visible imagery and ASDI flight routes

This eerie absence of flights in the Northeast is being felt throughout the entire nation, and even worldwide as a number of international flights are stranded abroad. It is a ripple effect caused by displacement of both planes and crews at various airports. For example, a flight from JFK to ORD may then go on to LAX, so if it is stranded in JFK, the LAX flight will be subsequently affected. Additionally, if the flight crew are also stranded, those flights they were meant to move on to once in ORD will then be short personnel, causing further delays as replacements are required. While ground stops are scheduled to be lifted early Tuesday, it will take quite some time before airspace operations have completely returned to normal.

In an effort to avoid as much displacement as possible, a number of airports in the Northeast got as many airplanes out of the area as possible before the storm hit. However, even with these preparations, this will not come cheap to the airlines as they have been waiving fees and refunding tickets for those cancelled flights and are also responsible for putting stranded flight crews up in hotels until the storm passes. Delta Airlines, in particular, has hubs in LGA, JFK, and ATL, with many flights also in and out of DCA and BOS.

Here at the AWC (under gorgeous, sunny skies I might add), the extent of this very large storm is easily seen through our satellite imagery. The focus now has shifted to providing accurate forecasts for the next few days so that aviation operations can slowly return to normal.

Sandy ready to visit the Mid-Atlantic tonight

Posted by Michael Folmer on 10/29/2012
Posted in: Microwave, MODIS, RGB, VIIRS. 2 Comments

This will be a short post to update you on some incredible satellite imagery that is assisting forecasters today. Some of it is very new and due to some incredible hard work behind the scenes at CIMSS/SSEC University of Wisconsin-Madison and NASA SPoRT, we have these available for the blogs and some of it in operations at the Hydrometeorological Prediction Center, the Ocean Prediction Center, the NESDIS Satellite Analysis Branch, and the Hurricane Center. Thank you everyone for your help!

Suomi NPP VIIRS Day-Night Band (DNB) composite of Sandy courtesy of CIMSS/SSEC/University of Wisconsin-Madison valid on 10/29/12.

The Suomi NPP VIIRS Day-Night Band image above shows Sandy overnight with a “visible” like image thanks to our full moon. This same full moon is already aiding in the astronomical high tides on top of the storm surge and large fetch. At last report, Atlantic City is completely underwater by a few feet and chunks of boardwalk are destroyed up and down the NJ coastline.

GOES-14 SRSO of Sandy on 10/29/12 with GLD-360 1-min lightning overlaid courtesy of Vaisala. Click on image to animate.

The GOES-14 Super Rapid Scan Operations (SRSO) is running at the NCWCP today to assist the forecasters with 1-min imagery at 1 km resolution. This could help HPC, OPC, and SAB look for structural changes in Sandy as she makes her approach to shore this evening. Note the complete lack of cloud-to-ground lightning in the core of the storm, while you see occasional lightning strikes in the bands hundreds of miles to the east. This is definitely one of the larges storms I’ve seen in my relatively short career!

GOES-Sounder RGB Air Mass product valid at 15z on 10/29/12 courtesy of CIRA and NASA SPoRT.

Last week I started to describe some of the upper-level features that would play a role in moving Sandy towards the East Coast. Today, the red “L” indicates the approximate location of the upper-level low that is cutting off and moving Sandy towards the coast. The black “L” is Sandy and shows the proximity. The red area highlighted shows the dry, stratospheric air on the periphery of Sandy, but notice how there is no sign of that over the hurricane? Sandy has been able to re-attain its more tropical look which has led to significant deepening and increases in wind. This tool has been used at HPC to help with the placement and timing of the features when compared to model solutions.

MODIS RGB Air Mass product valid at 0709z on 10/29/12 which shows a much higher resolution image at ~2 km. Image courtesy of NASA SPoRT.

The MODIS RGB Air Mass product above shows a much higher resolution image of the Sandy-Upper-low interaction. I again show the approximate location of the upper-low with the red “L” and the outlined area is the dry stratospheric air and notice there is more than in the previous image. A full transition to extratropical will occur tonight, but that doesn’t matter anymore as Sandy’s effects are already being felt even in DC and Baltimore.

The AMSR-2 image showing heavy rain in the blue area.

In addition to S-NPP, NOAA JPSS will be providing global data from the new Japanese AMSR-2 sensor to NOAA operational users later next year. AMSR-2 is the follow-on to AMSR-E which is on NASA’s AQUA satellite but failed last year. AMSR-2 will provide many capabilities including instantaneous rainfall rates as it flies over. The figure above is the 89V channel of AMSR-E, the blue area is associated with the heaviest rainfall rates from Sandy. Thank you to Mitch Goldberg from JPSS for providing me with this description! Special thanks to Fuzhong Weng and his team for providing us with this outstanding image.

If you are on the East Coast, be safe! For everyone else, I’m not sure I will be able to post anymore blogs for a while on here. I am leaving the reigns in the hands of Amanda Terborg (Satellite Liaison at the Aviation Weather Center) and Chris Siewert (Satellite Liaison at the Storm Prediction Center) to keep you all updated.

I would also like to give a shout-out to the forecasters at HPC, OPC and NHC along with the satellite analysts at SAB for doing a spectacular job during this historic event. I hope everyone that reads this understands the amount of pressure that is on a forecaster when trying to relay information to the public about the severity of what we are seeing and will see tonight. Thank you!

Thanks for reading!

VIIRS imagery of Sandy

Posted by Michael Folmer on 10/28/2012
Posted in: RGB, VIIRS. Leave a comment

As we are in full preparation mode in the DC/Baltimore area, I thought I would share a couple very interesting VIIRS images with you, courtesy of CIMSS at the University of Wisconsin-Madison and NASA SPoRT, through a joint project with JPSS. Sandy’s track forecast hasn’t changed much and I think I’ve covered the threats in the last few posts. Now let’s focus on where we are as of the last 24 hours.

The Suomi NPP VIIRS RGB Air Mass image using Google Earth valid yesterday, 10/27/12. Image courtesy of NASA SPoRT.

The VIIRS RGB Air Mass image above from yesterday shows the very high resolution of the VIIRS instrument when analyzing a complex storm such as Sandy. Everything to the right of the red line is very dry air at high altitude that is cutting into Sandy’s tropical environment. What is the source region for this dry air? Believe it or not, it is most likely due to stratospheric dry air from an old upper low in the Western Caribbean that got tangled up with Sandy. The dry air is introduced through something called a tropopause fold. All this means is that this feature introduces a non-tropical air mass into a tropical air mass, hence the hybrid, half-storm look on satellite.

Suomi NPP VIIRS Day-Night band image from 0625z on 10/28/12. Image courtesy of CIMSS/SSEC/University of Wisconsin-Madison and NOAA/NASA/JPSS Project.

Much like yesterday morning, the image above is the day-night band on the Suomi NPP VIIRS instrument. Again, this is the middle of the night and the “day-time like” image is courtesy of our full moon. See the city lights along the East Coast? Absolutely amazing what this satellite can provide to forecasters! A special thank you again to Liam Gumley of CIMSS/SSEC/University of Wisconsin-Madison for working on this in early morning hours this morning!

Suomi NPP VIIRS day-night band and infrared imagey with surface pressures and buoy observations overlaid. Image courtesy of the CIMSS/SSEC/University of Wisconsin-Madison satellite blog.

The final image today shows a close-up view of the day-night band and infrared image (click on image for short animation) with surface pressures and buoy observations overlaid. The details provided by these two bands will be able to assist forecasters in detecting minute storm-structure and environmental changes, even though it comes from a polar orbiting satellite. We don’t get many passes over the U.S. by this satellite per day, but an image like this could be critical in helping the forecaster detect these changes.

I will try to post again later today with a more detailed breakdown of the large scale environment affecting Sandy. Thanks for reading!

Sandy the Troublemaker, pt 4: the phasing begins!

Posted by Michael Folmer on 10/27/2012
Posted in: MODIS, RGB, Super Rapid Scan. Tagged: , , , , . Leave a comment

Growing up on the Jersey shore, I would wonder whether it was ever possible for a hurricane to come in off the ocean and hit NJ head-on. Oh, my naive youth! I guess Sandy is about to show us that anything is possible!

Today’s post is more to show you some of the great tools we are using to help analyze the large-scale pattern interactions with Sandy. Please note that even though the latest NHC forecast philosophy calls for Sandy to become post-tropical (no longer considered a hurricane) about 120 miles off the NJ coastline, there will be winds close to hurricane strength near the NJ coastline, while farther inland hurricane force gusts are certain a good possibility!

GOES-14 visible imagery in super rapid scan operations (SRSO) with 1-min lightning overlaid courtesy of the Vaisala GLD-360.

The animation above (click on the image to open in a larger screen) shows us a special GOES-14 super rapid scan of Hurricane Sandy on 10/27/12 with 1-min lightning overlaid. Notice there is very little lightning and much of it is in the arcing band to the north and east of Sandy’s center. This imagery is being used at HPC and the Ocean Prediction Center (OPC) during this entire event to showcase future capabilities of GOES-R. This helps forecasters monitor convective trends near the core and outer bands as Sandy transitions to a hybrid storm.

For a longer loop, minus the lightning: http://tinyurl.com/955fvvd. Thank you to Timothy Schmidt from NESDIS STAR for providing the animation!

GOES-Sounder RGB Air Mass product with features highlighted valid at 20z on 10/27/12.

The GOES-Sounder RGB Air Mass product above continues the story-line I started a few days ago. The shortwave (upper-level low circled in red) that is responsible to tangling Sandy with the Mid-Atlantic is now diving southeast at a rapid clip. This low (red “L”) will continue east-southeast overnight and you can see the effects of its influence on Sandy by the fanning out of the upper-level clouds to the west-northwest. As this occurs, Sandy (black “L”) will first move north-northeast into tomorrow, before being captured by the aforementioned shortwave. I highlighted in the yellow-circle some obvious dry air (red-shading) in the Sandy’s eastern quadrant. This is indicative of significant drying at upper-levels, most likely associated with a stratospheric intrusion, which has assisted in the hybrid nature of Sandy.

Although not shown today, the blocking in the Atlantic is already causing a significant atmospheric traffic jam. The large ocean storm is still moving southeast and the upper ridge will block any possible escape of Sandy, therefore allowing this highly unusual northwest-west track into either DE or NJ.

The MODIS RGB Air Mass product valid at 1828z on 10/27/12.

The final image today is courtesy of the MODIS instrument on NASA’s AQUA satellite. This version of the RGB Air Mass product is much higher resolution than the GOES-Sounder version, but it is a polar orbiter, therefore you only get a few images a day. Notice the amount of red-shading wrapping around the eastern quadrant of Sandy (yellow-circle). This shows us that the tropical to extratropical transition is underway and with the added energy coming in from the west, we will likely see Sandy deepen further from its current 961 mb pressure. This means the winds could actually increase despite the classification!

Hopefully everyone along the Mid-Atlantic and southern New England have made their preparations. Conditions will go downhill starting tomorrow. Again, the main impacts will be high wind, heavy rainfall, severe coastal flooding (4-8 feet in spots along the Delmarva and NJ), and mountain snows! What a storm!

I will try to update the blog on Sunday morning. Thanks for reading!

Overnight “Visible” View of Sandy

Posted by Michael Folmer on 10/27/2012
Posted in: Uncategorized, VIIRS. 3 Comments

While I plan on writing a more general update later today, I thought you would find the image below interesting. This is a “visible” satellite image at night courtesy of the Day-Night Band on the Visible Infrared Imaging Radiometer Suite (VIIRS) located on the Suomi National Polar-orbiting Partnership (NPP) satellite. Suomi NPP is a new NASA/NOAA polar orbiting satellite for improving weather forecasting and is part of the Joint Polar Satellite System (JPSS). The Day-Night Band is one of many capabilities that NPP will provide over the next few years!

In the image, you will notice the city lights along the East Coast as Sandy lurks offshore. The details offered by an overnight satellite image allow forecasters to monitor slight nuances in convective development and this is achieved by using the sun’s reflected light on the moon which is at 93% tonight.

A special thank you to Liam Gumley from CIMSS/SSEC-University of Wisconsin-Madison for producing this image for us in the early hours this morning!

The Day-Night Band on the VIIRS instrument aboard the Suomi NPP satellite.

Thanks for reading!

What to do with Sandy, Pt. III – the saga continues!?

Posted by Michael Folmer on 10/26/2012
Posted in: Uncategorized. Tagged: , , , , . 2 Comments

It’s been a very busy day here at the NOAA Center for Weather and Climate Prediction (NCWCP) and it’s only going to continue on this pace through the weekend. The good news is that we have some great GOES-R and JPSS products to assist the forecasters in their forecast philosophies, separate from the model mayhem we have all been hearing about or observing. I thought I would continue on a similar path as recent days and show you the players on the field as it is now another 24 hours later and some interesting things are beginning to take shape that will ultimately define the exact track of Hurricane Sandy.

If you look at the above image of Sandy, you might ask. . .is she naked? Where did the thunderstorms go? Or even. . .what’s the big deal? Sandy is undergoing some serious shear at this moment with mid to upper level winds averaging around 50 knots (60 mph) helping to fan out the upper cloud pattern and strip the “eye-like” feature of deep thunderstorms. This does not mean that Sandy is not producing hurricane force winds as has been observed today by aircraft measurements. So what happened? You ask great questions. . .

The upper low that was south and west of Sandy yesterday has gotten tangled up with the hurricane and therefore we are left with a very hybrid looking hurricane. This is still a significant threat for someone. . .but how do we get there? I will tell you!

GOES-Sounder RGB Air Mass product with the 5 pm EDT NHC forecast track of Hurricane Sandy overlaid.

As you can see above, the playing field has gotten a bit more crowded than it was the last two days and that is due to a new feature that will dictate the path of Sandy. The white line more or less outlines the developing longwave trough (large-scale pocket of cooler air). The first shortwave (red “L” in the yellow circle) is getting ready to move out of the base of the longwave trough, but will help to push Sandy a bit more north-northeast over the next 24 hours. The new player is the red “L” in the red circle in the upper-left corner. As you can see, I (poorly) drew the projected path of this feature that will help to form a closed upper-level low to the southwest of Sandy by Sunday-Monday. This will help to steer Sandy back towards the Mid-Atlantic or Southern New England by the Monday-Tuesday time frame.

Although I did not highlight the area, there is still some orange coloring over Sandy which is indicative of the slow transition into a hybrid storm as it indicates some dry stratospheric air has gotten entangled with the storm. It will be interesting over the next few days to see how the upstream shortwave (latter red “L”) transfers energy to Sandy, effectively strengthening the storm!

SEVIRI RGB Air Mass product over the North Atlantic valid at 21z on 10/26/12.

Meanwhile, the North Atlantic has gotten more complicated as the higher latitude blocking is in full swing. The white outlined region is the expanding area of upper-level high pressure or ridge that is setting up this “blocky pattern”. The traffic jam has started and the large, complex ocean storm in the red circle with two significant shortwaves (red “L’s”) will shift southeast over the weekend, then sit and spin. . .for a while. This helps to strengthen the ridge to the north and will lead to a road-block with subsequent detour for Sandy. So, blame Greenland for being a favored location for things like this!

The black circle is all that is left of Tony. I was way wrong on its evolution as I thought the larger system to the west would absorb the system, but it is wandering harmlessly towards the Canary Islands. I’m sure they can use the rain there. Finally, the little red “L” is our wandering upper-level low that will continue to bob around the North Atlantic on its long journey west. We will talk about that little guy in future posts.

So, what does this mean for the East Coast? All that blocking, the complex evolution of the upper-level low forming over the Carolinas, and a hurricane will lead to very bad weather for many people up and down the East Coast, but the emphasis continues to be on the Mid-Atlantic. Some models bring the storm towards eastern Long Island and Southern New England, but I’m not jumping on that option just yet. Very high winds, heavy rain, severe coastal flooding (remember earlier posts about the full moon, large fetch, and storm surge), and potential thumping snow in the Appalachians still remain a strong possibility. We have another 24-36 hours to fully digest and analyze this complex situation, but residents along the coast and inland should prepare anyway.

I leave you with a couple high resolution images of Sandy from the new Suomi NPP satellite’s VIIRS instrument. The first image is the Day-Night band showing a “visible-like” satellite image using light from our moon! The second images is the infrared band showing very fine details in the cloud pattern with a resolution of 375 meters! Amazing stuff for sure! A special thank you goes to Kathy Strabala for providing the imagery.

The NPP VIIRS day-night band image from 0702z on 10/26/12.

VIIRS Infrared image at 375 m resolution valid at 0702z on 10/26/12.

I will continue to keep you informed over the weekend. Expect this to get more interesting as we approach the event.