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.
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.
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.
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.
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.
STATUS: IOP today through Monday
VORTEX-SE will be conducting observations over the next several days that are primarily designed to improve our approaches to storm studies in the Southeast.
The brand new University of Oklahoma SMART-Radar has joined the existing SMART-Radar in the Monroe Louisiana area this evening. We have been fairly confident for the past two days that there would not be initiation of significant convection in that region, but we have the radars in place just in case. If a cell(s) formed this evening, we would be able to obtain multiple-Doppler observations teaming up with the University of Louisiana-Monroe S-band research radar. But the atmosphere is gradually stabilizing and quieting down in that area, and research-worthy storms are very unlikely this evening.
Starting tomorrow (Saturday/17 March) our focus will shift up to the northern Alabama subdomain near the University of Alabama-Huntsville (UAH). There, the two OU radars will team up with the UAH ARMOR research radar and the MAX mobile x-band radar, as well as several other important platforms operated by UAH primarily to measure changes in the lower atmosphere at frequent time intervals. The NOAA P-3 hurricane hunter aircraft is also on standby in Huntsville, their base for this spring.
On Saturday and Sunday, strong upper winds will persist across most of the Southeast, and CAPE will gradually be increasing as moisture advances slowly northeast from the western Gulf of Mexico. At just about any time Saturday and Sunday, potentially tornadic (very low probability) storms are possible in the northern Alabama area, so it’s best for us to shift our resources up to that area.
But the main consideration in our decisions today is that the models are suggesting a very potent set up across northern AL on Monday. The forecast looks perilous, and experience suggests that often forecasts of large severe weather probabilities this far in advance do not pan out. But we are watching Monday warily.
Our IOP will likely end Monday night, with a few days of quiet and rest in store after that.
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.
Status: GO for Saturday IOP
Teams are enroute, or will soon be, to the Monroe LA subdomain of VORTEX-SE. This is one of two subdomains we will use this year, depending on the forecasted weather.
A narrow mid-tropospheric jet is forecast to be advancing toward Louisiana from the west-northwest on Saturday. To the north of this jet, lift will be strong, likely leading to quite a bit of precipitation and low-level cooling. To the south, the air will be sinking which should enhance the “lid” and possibly limit convection. Between these two regions, there should be a narrow goldilocks zone of sufficient CAPE and strong shear that could support some low-level rotation. Of course, many things can go wrong (and usually do, to the benefit of the general public) with this scenario and any convection may be non-rotating.
We will deploy one mobile C-band “SMART-Radar” from OU to pair with the U. Louisiana-Monroe S-band research radar, and ULM mobile sounding teams. The NOAA P-3 aircraft will likely take off midday Saturday and head toward Louisiana, if this forecast holds up. They will make radar observations of the most interesting storms, and will focus on storms over the ground radar domain near Monroe when storms are present there.
There is a slim chance that there will be tornado potential in the Georgia/N Florida area on Sunday. Although we don’t have a ground subdomain there, the P-3 aircraft may fly a mission to observe storms in that region.
Thereafter, we expect quiet conditions until the following weekend.
One more time with the caveat: forecasting conditions for a field observing program are very different than forecasting for more general purposes. We are generally fine with a “busted forecast”, especially if we are able to obtain data to tell us why we busted. Learning what processes reduce tornado potential are almost as interesting as catching tornadic events. Because tornadoes are rare, we have to observe most everything that comes along with even a little potential. And this spring, our focus is not so much on the physical processes in the atmosphere in the Southeast, but learning how to make much better observations in this difficult region.
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.
STATUS: IOP Watch
We are anticipating a possible IOP on Saturday and Saturday night.
A trough will deepen across the northern High Plains late Friday, causing an acceleration of the flow in the upper atmosphere across OK on Saturday. This trough will consolidate somewhat as it approaches MO/AR, and a surface low will deepen fairly rapidly somewhere in the region centered near Memphis.
The developing southerly flow should bring Gulf moisture back into the Arklatex region Friday night, although the confidence in the “quality” of this moisture is not high. A series of runs of the operational GFS show a subtle decrease with time in the forecasted dewpoints across the region on Saturday, and an associated decrease in CAPE. We expect that drier air will remain in place across GA, and perhaps parts of AL, because the pattern and fast-moving wave will not allow moisture to return to those areas. So any complex of storms that develop in the Arklatex region Saturday will eventually run out of juice as they race east.
Another question (seemingly always a major issue in VORTEX-SE) is the likelihood, timing, and effect of an MCS in the Gulf of Mexico. These systems are probably associated with subtle waves in the jet stream, and those waves may not be well forecast until within 24 hours of passage because prior to that time they are somewhere out over the Pacific.
The current best guess is that storms will form in far east Texas on Saturday, with at least some tornado potential, and roll east across Louisiana in the evening, and perhaps into MS/AL during the night. We expect that our most likely subdomain for combined airborne and surface radar observations will be the U. Louisiana-Monroe subdomain.
Bear in mind when reading these discussions that we are forecasting conditions required for successful research operations. We have a very high tolerance for erroneous forecasts of possible tornadoes; they are a rare phenomenon and it is a lot more painful to miss an observing opportunity than it is to be operating and nothing happens.
A final IOP decision will be made Thursday afternoon, 8 March.