Mesoscale Observations of
Convective Initiation and Supercell Experiment -'00 & '01
Update: MOCISE will collaborate with pre-IHOP and COMPASS in 2001.
I'll update this page as information becomes available over the next few months. Information pertaining to the '01 effort is preceded by a *.
A plethora of questions pertaining to convective initiation have been
generated from ongoing analysis of
VORTEX, MOCISE and
STEPS data. Additionally, recent
publications using data collected during VORTEX have documented various
interactions of tornadic supercells with boundaries. It has become
increasingly clear that an investigation of the environmental mesoscale
thermodynamics and kinematics along and near various boundaries is required
in order to understand the underlying dynamics relevant to thunderstorm convective
Until a more complete characterization of boundaries in general, and the
boundaries associated with tornadic supercells in particular, is acheived
our knowledge will remain limited. This observational study will add
comprehensive information for detailed boundary characterizations and will
test applicable hypotheses. Emphasis will be placed on a variety of
mesoscale boundaries, including the
outflow boundaries, and quasi-stationary fronts as well as supercells.
Field Operations Plan:
* The mobile mesonets and mobile laboratory will be located at Texas Tech University. Field operations will focus primarily to the right of line from
2000 operating domain (schematic):
The operations center will be run at Texas Tech University. Field operations will focus primarily in the Texas and Oklahoma Panhandles, West Texas and Western Oklahoma.
- 1. *Obtain data documenting surface and boundary layer thermodynamics inconjuntion with dual Doppler radar data during the evolution of mesoscale boundaries.
- 2. Obtain data documenting coherent kilometer-scale kinematic flow structures and moisture gradients along boundaries.
- 3. * Obtain data documenting atmospheric surface variables in conjunction with dual Doppler radar data within deep moist convection.
* June 1 - June 30, 2001
April 1 - May 15, 2000
- * Six Mobile Mesonet stations (two will remain in OUN) from the Joint Mobile Research Facility
of the University of Oklahoma, Texas Tech University (TTU), and the National
Severe Storms Laboratory. Mobile Mesonets will sample the surface
meteorological conditions along and across preconvective surface boundaries and utilized for deep moist convective studies for COMPASS.
- * Two SMART-Radars. These will be tested in preconvective boundary layer conditions similar to what will be
encountered in IHOP. The radars will also be used for the COMPASS objectives.
- * One NSSL mobile laboratory. M-CLASS soundings will be used to sample boundary layer conditions
across the boundaries under investigation. Pre-storm environmental soundings and updraft soundings will also be released
- Eight Mobile Mesonet stations from the Joint Mobile Research Facility
of the University of Oklahoma, Texas Tech University (TTU), and the National
Severe Storms Laboratory. Mobile Mesonets will sample the surface
meteorological conditions along boundaries.
- One NSSL Mobile Sounding System (M-CLASS) to document the upper air
environment in the dryline moisture transition zone, both sides of the
dryline and/or boundary under investigation.
Convective Initiation Studies
The Great Plains dryline will be the focus for a majority of the experiment.
In order to achieve the project's objectives, quiescent and/or slow ( < 6 m/s)
transient dryline events will be targeted. This will enable a detailed
sampling of the surface gradients and coherent flow structures embedded
within the dryline. Examples are online of Mobile Mesonet (MM) observations
and the Denver
Convergence and Vorticity Zone (DCVZ). Convectively active and/or fast-moving drylines
will not be considered for operations. Similarly, outflow boundaries and
quasi-stationary fronts moving over 6 m/s will not be targeted.
Previous MM operations during VORTEX and HAL have
determined that a variety of vehicle speeds are necessary for proper
observations along surface boundaries. The MM vehicles will perform
opposing transects of the boundary in pairs. One pair will perform transect legs
normal to the boundary, proceeding at about 40 mph and ending each leg from
1.0 to 2.0 miles on either side of the boundary. This vehicle speed is
ideal to resolve the larger flow structures, i.e., embedded eddies. A
second pair of MMs will sample the boundary using the same road
at 5 mph (see schematic). These slower sampling speeds will permit a fine-scale
quantification of gradients in moisture and temperature across the boundary.
The transect legs will cease 0.5 to 1.0 mile either side of the boundary.
* The third pair of MMs will operate similarly on a parallel road
1 mile up or downstream of the first two pairs. The additional sampling
along the second parallel road will provide essential data to resolve and
document the temporal evolution of the boundary. *Additionally, the third pair will operate along the dryline
sampling the along-line moisture and thermal variability.
The M-CLASS unit will launch soundings from 2.0 to 4.0 miles on either side
of the boundary. Depending on the mission, soundings will generally be
deployed once every 1.0 to 1.5 hours. These soundings will provide
additional data for temporal characterizations. Resolutions should be
adequate for observing the evolution of boundary layer thermodynamics and
kinematics. Soundings will be launched directly within the moisture
transition zone on the dryline and should enable the detection of moisture
plumes emanating from the boundary (assuming plumes are present and thus
sampled within the sounding trajectory path as it rises through the boundary
layer). When the M-CLASS unit is not preparing for a launch, the vehicle
will join one MM team and conduct 40 mph transects of the boundary.
*If operations are conducted in west Texas, target preference will be given to the region bounded within the
West Texas Mesonet array.
The forward flank (FF) of supercells
(see schematic) will be targeted for
investigation. The common conceptual model of a supercell (Lemon and Doswell, 1979,
Mon. Wea. Rev.) shows a storm-scale front extending along the forward-flank
precipitation region, presumably produced by evaporative cooling of forward flank air.
However, work by Markowski et al. (1998, Mon. Wea. Rev.) has shown that for VORTEX
storms, the forward-flank front was often absent, particularly when the supercell was on
the cool side of a mesoscale boundary. This is easily understood in light of the fact that
the air on the cool side of these boundaries is typically cool and quite humid, greatly
reducing the potential for evaporation from the forward flank.
We wish to resume observations of forward flank baroclinity during MOCISE in order
to determine if any supercells exhibit significant baroclinity there, and if so, how these
supercells might be structurally different than storms that do not have this baroclinity.
Low precipitation (LP) and Classic (CL)
supercells should provide the best opportunities for achieving project
goals. High precipitation (HP), line segments, and squall lines will not be
targeted. If a LP of CL should evolve and/or grow upscale into either a HP
or squall line, operations on that storm will be terminated.
MMs will be
grouped in teams of two performing opposing transects normal to the FF.
The individual pairs of MMs will travel separated on parallel roads spaced
~1 mile part and the teams will leap-frog one another, each beginning a new
transect further downstream as they keep pace with the storm.
This will allow for prolonged sampling of the FF and documentation of the FF
temporal evolution. The M-CLASS unit will not launch soundings while engaged on a supercell.
The vehicle will be used as a MM working in unison with one
of the MM pairs.
Field Coordinator: The field coordinator (FC) is responsible for all activities pertaining to MOCISE field
operations. These responsibilities include but are not limited to the following: monitoring status and availability of vehicles;
procuring personnel and equipment; directing experiments; road network density and navigation;
logging travel time; communications status; determining next-day target region potential; communicating with Nowcaster,
M-CLASS; and the deployment and orchestration of the mobile and stationary mesonets on a mission.
Nowcaster: The Nowcaster will provide meteorological support to the FC once the teams are
in the field. Based on mesoscale analysis, profilers, satellite and radar, the Nowcaster will provide support during actual
missions. Nowcasting will usually be provided by Dr. Erik Rasmussen in Boulder (BNC). When BNC is unavailable,
Jim Johnson with the Dodge City National Weather Service Forecast Office (DNC) will assist with nowcasting and short term forecasting. Communications
between the Nowcaster and the FC will occur once
an hour. Either individual, depending on environmental changes, will initiate the communiqué. Once a target is chosen, the
frequency of contact may or may not increase depending on the pace of environmental changes and the objectives of the
mission. A quiescent dryline needs little nowcast support as compared to a supercell mission.
Mobile mesonets will be assigned two persons per car: the driver and the captain. The driver’s sole
responsibility is the safe operation of the vehicle. The captain is responsible for communications with the field coordinator
(FC), maintaining the operation of the mesonet, data sampling and logging, and will assist the driver with road directions
M-CLASS unit will be operated by three people: a driver, captain, and an assistant to the captain. The driver’s
sole responsibility is the safe operation of the vehicle. The captain is responsible for conducting and operating the sounding
launches, sounding and mobile mesonet data collection, monitoring the M-CLASS electronics and equipment, and
communicating with the FC. The assistant captain will aid in sounding launches and data collection, and mobile mesonet
sampling, as well as aid the driver with navigation.
- Safety:-link to VORTEX guide lines.
- Participants should be thoroughly familiar with the safety standards established within the document linked above.
These same rules apply for all MOCISE participants and will be strictly adhered to.
In MOCISE, the standard VORTEX radio protocol will be used. It's quite simple
- Keep VHF communications to a minimum to reduce data contamination.
- At the start of a conversation, use the template "Other Team [this is] My Team". For example, if you are P4 and wish to speak to P2, say "P2 this is P4" or simply "P2, P4".
- There is no need to say "over" or "clear" at the end of a conversation; just get off the radio.
- No profanity. No conversations that make light of bad weather; others are listening. These channels are for official use, not idle chatter.
While engaged on an intercept use channels ONLY for official communications; we will be more relaxed while an intercept is not going on.
We will utilize two VHF simplex channels, depending on the situation.
This will be channels X.XX and Y.YY on the MM VHF radios.
Cell phone coverage is rather sparse in some of the MOCISE region; the FC, .
unit team, and the M-CLASS team will have project cell phones in the vehicles.
National Weather Service:
- The National Weather Service Forecast Office (WFO) in Lubbock
(LBB), TX will aid in the operational efforts of MOCISE. The LBB
WFO will also provide both resources (also see data archival) and personnel to the project.
The WFO will monitor the Spur, TX (KSPR)
Campbell unit observations and also increase the temporal resolution
of the observations from one-hour, to fifteen minutes. The LBB WFO
will closely monitor the Lubbock WSR-88D Archive II data collection
system when the project is operating in their warning area. Additionally,
when regional precipitation and bordering WSR-88D operations permit,
the LBB WFO will prolong the use of VCP 32 volume scans before
switching to VCP 11. The lengthen VCP 32 window will aid the MOCISE
forecasters and researchers in better resolving and monitoring radar "fine
Lines". Please note that during severe weather operations, the primary
mission of the NWS - protection of life and property - must take precedent
over MOCISE activities in the event that resources are insufficient to
accommodate both. Data and observations from the MOCISE data collection
will be relayed to the Lubbock WFO in real-time through the Nowcaster, to assist
in warning operations. Post-event verification operations will be relayed
directly to the LBB WFO by the FC. When possible MOCISE participants
will assist the LBB WFO in damage surveys. This may also include the
participation of Wind Engineers from TTU.
The Dodge City, KS WFO will help assist with nowcasting. Jim Johnson will head this effort for the office (see Nowcaster).
- Several individuals and the FC will conduct daily forecasting. The forecasting will commence the evening before a possible mission.
For logistical reasons, the forecast information will be shared via a very informal email exchange between the forecasters and the FC. The email
discussion is intended to aid the FC in determining a mission target area. Forecasting emphasis will be placed on the relevant data and
guidance pertinent to synoptic and mesoscale features for the following day. Ongoing overnight convection will be closely monitored with
regard to outflow boundary development. Given only the evening sounding and numerical model runs will be available, compounded by
a 18-hr mesoscale forecast, any target areas chosen should be considered preliminary until the updated morning forecast is
distributed. Once the FC has decided upon a preliminary target, he will write a status message and forecast discussion. This will
be emailed directly to MOCISE participants. The forecast will consist of a detailed discussion over the synoptic and mesoscale environment.
A "GO”, “NO-GO”, or “STAND-BY" status will be issued in the email. The time the email is sent out will vary; therefore, participants are encouraged
to read the SPC Day-2 forecast discussion before the receipt of the evening forecast. This will provide the participant with a possible "heads up"
for the next day. It is stressed that the SPC outlooks should not be viewed as a gauge in determining a "GO”, “NO-GO" decision. The forecasting
objectives of SPC are vastly different then MOCISE's. If the evening status message is a “STAND-BY”, information leading to the decision delay
will be explained.
- When the evening status message and forecast discussion contains a "GO” or "STAND-BY" condition, morning forecast
will occur. Forecasting emphasis will be placed on current remote sensing instruments. The forecasting time frame will preclude
the use of 12Z soundings and numerical guidance. Forecasts will include but are not limited to, boundary(ies) placement and
movement, expected time of convective initiation, supercell type(s) given the probability of supercells and likely motion, as well
as tactical operations for that day. In formulating his decision, the FC will also consider how the terrain and vegetation
in the target area may effect operations; the relative amount of data already for various study objectives. The
feasibility of reaching the target and thus insuring that the teams arrive at the potential boundary
area before initiation of deep convection will be carefully examined. Once the FC has made a decision for the day, a second
email will be sent containing the mission status. The email will be sent to all participants no later than 1700 UTC. It is possible
that a morning status message will be a “STAND-BY”. If that is the case, information pertaining to this decision will be
conveyed along with a time frame for a later update. The majority of MOCISE participants are TTU grad students and in
close academic proximity to the FC. This group of participants will be updated verbally in addition to the email. The students’
exam schedules will be taken into account in determining the "GO" "NO-GO" decision.
Data sources and archival:
- Several sources are providing specialized real-time data and the archiving of remote
sensing and model data. Jim Bresch with the Mesoscale and Microscale Meteorology Division,
at NCAR, will maintain a real-time MM5, 30-km resolution sector centered over Oklahoma. Eric
Nelson with the College of DuPage, neXlab, is providing a Southern Plains ETA
sector. TTU will maintain the ingestion and archive NIDS, satellite, soundings, ACARS, profiler, and surface data. Archived level II
WSR-88D data will be ordered as needed through NCDC. The LBB WFO will archive the ETA model
output and the KSPR Campbell mesonet site. Observational field notes and mission summaries will be
maintained by the FC. These will be made available on-line as time permits. The mobile mesonet
and M-CLASS data will be available to the community after rigorous quality assurance steps
have been completed.