STATUS: 28 November 2018 IOP #2

With the news being about Midwest blizzards, Black Friday, and Cyber Monday, it doesn’t seem right that VORTEX-SE should be active. But we are.

Over the last couple of years, we have grown increasingly concerned about observing the “cool season” tornado events in the Southeast.

The peak occurrence of killer tornadoes in the Southeast spans a broad season from October through early May. Tornadoes this time of year are especially concerning because of the perception that tornadoes are a springtime phenomenon. People let their guard down during the fall and winter.

On Friday, an upper wave and jet stream will be plowing into the Southern Plains. As pressures fall, strong low-level flow will develop off of the Gulf of Mexico, transporting warm humid air inland. Combined with the upper level jet stream flow, profiles of temperature, humidity, and wind ought to become favorable for increased tornado potential, first in east TX, LA, and AR Friday evening, and spreading east into MS Friday night (30 Nov). The system will then chug east into AL/GA on Saturday. At some point, it will outrun the richer Gulf moisture and move into the cooler drier continental air left behind by the last system over the eastern US, and the tornado threat should diminish.

This cool season, VORTEX-SE will be doing an experiment aimed primarily at improving forecasts of tornadoes on time scales from a few hours to about 2 days. Starting at about the time the upper system enters the Plains, many Southeast NWS sites will be launching soundings every six hours, continuing for 48 hours. In addition, university and NOAA Lab partners will be launching soundings at the same times from College Station TX (Texas A&M), Fort Smith AR (NSSL), Monroe and Breaux Bridge LA (University of Louisiana at Monroe), Memphis TN and Starkville MS (Mississippi State), Mobile AL (University of South Alabama), Huntsville AL (University of Alabama-Huntsville), and Montgomery AL and Oak Ridge TN (NOAA Air Resources Lab, Atmospheric Turbulence and Diffusion Division).

In addition to this regional-scale observing campaign, we will be doing “nested” finer-scale observations in northern AL to get a look the details of the features we detect moving through the larger domain. This will include two “CLAMPS” profiling systems from NSSL and OU, as well as profiling, mobile radar, and mobile sounding systems from the University of Alabama-Huntsville. And the Texas Tech instrumented surface network (“Stesonet”) will be making observations across northern AL and southern TN, with instruments spaced roughly in every county.

All of this is part of the ongoing VORTEX-SE effort to improve the forecasting of, and human response to, tornadoes in the Southeast. These tornadoes are unlike their Plains counterparts in that they occur across a longer part of the year, are much more likely to occur at night, and occur in complex scenarios and from storm types that just have not been studied very well in the past.

Erik

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STATUS UPDATE: 4:05 PM Tue 3 April

The NOAA P-3 is working a tornado-warned storm to the northwest of Batesville, and south of Melbourne, AR. Storms to the southwest of there continue to get more interesting as well, but are currently too difficult to operate on… the aircraft needs some space on the inflow side of a storm to gather research-worthy dual-Doppler data.

The storms are barreling east toward an evening encounter with our mobile radar network in NW AL.

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STATUS UPDATE: 19 March 2018

STATUS: Down

The IOP is completed. Several tornadic supercells were observed, with a number of tornadoes occurring. The level of damage is not clear yet.

We succeeded in collecting many volumes of multiple-Doppler data involving ground-based and airborne radars.

Many soundings were obtained, at an hourly interval, to document the evolution of the environment.

The next potential for operations appears to be toward next weekend.

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STATUS Update: 19 March 2018

STATUS: Operating.

One supercell with a low-level meso is moving through our multi-Doppler coverage northeast of Huntsville; the P-3 has been scanning this storm for most of its life. No tornadoes from this so far… lots of hail. This is the kind of data set we were seeking this year to test approaches to measuring 3D winds using multiple simultaneous Doppler radars.

Another supercell is forming south of Huntsville and moving toward Sand Mountain, also in good multi-Doppler coverage. This provides an alternative target for the P-3 aircraft if they have trouble scanning the northern storm.

New storms are forming in MS and will move into AL in a couple of hours. Low-level hodographs are starting to lengthen. A PDS tornado watch has been issued for all of our study area.

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STATUS: 19 March 2018

We are operating. All five ground-based radars are scanning, and the P-3 aircraft is attempting to find a way to scan the storm in NW AL. This storm has a tornado warning, and we suspect it will stay connected to the surface warm front as it continues east toward the Huntsville area in about an hour. Thereafter, it will enter our Doppler radar domain.

We still anticipate another round late this afternoon/evening.

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STATUS update: 18 March 2018

We have just finished our planning meeting. A number of sounding and profiling systems will be deployed across northern AL in the morning on Monday. We still expect a line of supercells to initiate around 2 PM in far eastern MS, and move east across northern AL at about 50 mph. The NOAA P-3 aircraft will take off from Huntsville at 2 PM. We expect the supercells to pass Huntsville around sunset, and then move on into Georgia. We will have five radars on the ground… ARMOR, two SMART-radars, MAX, and the Hytop WSR-88D, and these will be covering all of NE AL and far southern TN, generally east of I-65.

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STATUS: 18 March 2018

STATUS:IOP

We have moved the U. Oklahoma SMART-Radars to the northern AL subdomain at Huntsville, and all the needed platforms should be available for a mission tomorrow (Mon 19th).

Despite small run-to-run fluctuations, the numerical guidance continues to show the potential for tornadic supercells in the domain tomorrow. Some significant tornadoes may occur. This overall theme has been present in the forecasts since Thursday morning, but that’s no guarantee that it will come about.

I sent a special heads-up email this morning to a group of more than 20 researchers in the social, behavioral, and engineering sciences because many of these folks are engaged in studying how the lead-up to tornado events influences reactions to an actual threat, and many of them need to do research immediately following tornadoes or tornado warnings. We all hope for no suffering, while still being ready to learn how to reduce or prevent the suffering caused by future events.

Right now, we are expecting convection to develop in eastern MS around 2 PM, and sweep east across AL and into GA by sunset. The P-3 aircraft is scheduled to take off at 2 PM on Monday.

I will try to post an update just prior to our observing mission… midday Monday.

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STATUS: 10 March 2018

STATUS: IOP in progress

As of 2 PM CT, the NOAA P-3 aircraft is in the air.

Today’s situation seems to pick up where the last two seasons left off: very difficult to forecast the potential for tornadic storms in the Southeast, even a few hours in advance. For several days, the models had been painting a pretty consistent picture of the highest potential for research-worthy storms across N LA. Last night, the convection-allowing guidance such as the HRRR and the NAM-Nest (NAM-3km) jumped to a consistent idea of very little convection across N LA, but a band of storms with rotating updrafts moving across central AR this evening, and heading SE toward central MS tonight. This pretty much is smack dab in between our two subdomains (near Monroe, LA and Huntsville, AL).

Of course the P-3 can cover a lot of ground quickly, but the challenges of planning those missions is huge. They can only carry a certain amount of fuel, and obviously they have to spend a certain amount of time on the ground between missions. So the P-3 scientists have to decide today what they plan on doing tomorrow. And since there are targetable storms possible tomorrow in southern AL and GA, they opted to go ahead and fly at 2 PM today on an 8 hour mission, and have scheduled a mission for tomorrow as well.

As I write, the interesting storms are forming in eastern OK, and we will watch them closely to see if 1) they develop southeastward into AR early enough for the P-3 to study them, and 2) if they are showing signs of developing down toward the Monroe area where our ground-based radars are waiting.

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Spring 2018 observations begin

This spring, we are taking a breather from the style of experiments we conducted in 2016 and 2017. This is intended to give researchers some time to study data we have already collected, and to use new insights to improve our scientific questions and use of resources in future years.

However, the NOAA P-3 Hurricane Hunter aircraft will be used in VORTEX-SE this spring. This aircraft has a Doppler radar with a pair of antennas in the tail so that we can do analysis of the precipitation and winds in Southeast storms. One antenna looks slightly forward of the aircraft and the other slightly rearward. As the plane flies by a storm, along-beam velocities measured in these two separate “look angles” can be combined to give us the complete velocity at millions of points.

We have a huge challenge in VORTEX-SE owing to the terrain and vegetation to produce the kinds of mobile radar analyses that have been obtained comparatively routinely in the Great Plains. Until we can tackle this problem, we will not be able to do the sorts of detailed storm studies that can tell us how a particular tornado formed, and how the parent storm might have behaved differently than the fairly well-understood Great Plains cousins. So in addition to the NOAA P-3, we will be deploying three-radar networks consisting of University of Oklahoma SMART-Radars (dual-polarization mobile C-band radars) and either the U. Alabama-Huntsville C-band dual-polarization Doppler radar at Huntsville (known as ARMOR), or the U. Louisiana-Monroe S-band dual-polarization Doppler radar at Monroe. We want to know if such deployments of combined surface/airborne Doppler radars can be used to produce higher quality storm airflow analyses than other combinations of radars, and whether/not we can do a better job piecing together the airflow patterns in the crucial near-ground layer that is so important to tornado formation and longevity. Then, using this assessment, we can more effectively plan future observations to address VORTEX-SE science questions.

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