Regional and Mesoscale Meteorology Branch

A manuscript entitled, “The Role of GOES Satellite Imagery in Tracking Low-Level Moisture Advection” by D. Bikos, J. Weaver, and J. Braun that was originally submitted to Mon. Wea. Rev. and then re-directed to Weather and Forecasting by the editors, has been returned to the AMS after responding to minor reviewer comments. The paper had been accepted, but no publication date has been given.

The investigation into the mechanism behind thunderstorms having enhanced shortwave reflectivity continues. A recent idea appears to explain many of the highly-reflective storms observed: cloud droplet residence time within a thunderstorm updraft from cloud base to the homogeneous freezing level. Small residence times allow tiny cloud droplets to freeze homogeneously before having time to grow appreciably, resulting in the anvil being dominated by tiny ice crystals, which in turn results in the storm being reflective at 3.9 µm. In contrast, large residence times allow for more growth of the cloud droplets, which results in larger ice crystals at storm top and a less reflective 3.9 µm signature. Figure 1 shows this relationship. A manuscript on this topic will soon be submitted to Mon. Wea. Rev.

Figure 1. Mean 3.9 µm albedo plotted against cloud droplet residence time (seconds) between the lifted condensation level and the -38 ˚C level.  This quantity is estimated by dividing the cloud depth by the square root of twice the CAPE.  The satellite data were taken from 32 days during the summer of 2003 and 2004, over the portion of the U.S. covered by GOES-12.  Thermodynamic data come from the North American Regional Reanalysis, where the nearest grid point to each cloud was chosen .

A project has recently begun to investigate the use of satellite-retrieved particle effective radius to gain information about thunderstorm updraft strength. The project began with a meeting at CIRA with B. Rabin (NSSL), D. Rosenfeld ( Hebrew Univ.), B. Woodley (Woodley Assoc.), and J. Golden (FSL) to formulate a research plan. The first portion of the project is to collect data for 30-40 case studies. These cases have been selected, the satellite data obtained, and a web page providing satellite loops and other information has been created. A new web page was created to document ongoing research on Reflective Thunderstorm Tops:

http://rammb.cira.colostate.edu/research/severe/reflective.asp .

The RAMM Branch Severe Weather Research Webpage has been updated:

http://rammb.cira.colostate.edu/research/severe_weather.asp .

An abstract was submitted and accepted to the upcoming Satellite Conference at the annual AMS meeting in Atlanta entitled: “A climatological study of ice cloud reflectivity over the Continental US.”

Ocean heat content information is being used to produce forecasts of typhoon intensity at the Naval Research Laboratory, Monterey. Real-time heat content information is provided to NRL by G. Goni of the NOAA/AOML. This information is used in a recently developed version of the Statistical Typhoon Intensity Prediction Scheme that makes use of such information in the western North Pacific. Forecasts are produced in real time and are disseminated to the Joint Typhoon Warning Center for use in their forecasting duties. Result will be verified and compared at the end of the 2005 Typhoon Season. Figure 1 shows the expected improvement associate with the addition of ocean heat content to STIPS.

Figure 1. Mean absolute forecast errors (kt) and percent improvement over the previous version of the STIPS model associated with a similar model that takes into account the variation of the ocean heat content along the forecast track. Errors and improvements are based on dependent data.

Work continues on a satellite-only tropical cyclone surface wind analysis. This work combines in a specially developed objective analysis (cylindrical, variational) observations from feature tracked winds, SSMI winds, QuickScat winds, AMSU-derived 2-d wind fields, and IR-derived winds. The key ingredient is the recent development of an IR method to predict the winds associated with the core of the tropical cyclone using two pieces of information predicted from the IR imagery (size and radius of maximum winds) and other information provided from the tropical cyclone advisories (intensity, motion, and location). The combined analyses are run in real-time while the analysis is improved. The current version uses a standard flight-level to surface wind correction over water, and decreases (turns) these winds an additional 20% (20 degrees) over land. Examples are shown for the currently occurring tropical cyclones in Fig. 2.

Figure 2. Real-time satellite only tropical cyclone surface wind analyses created 18 UTC 22 September 2005 of all active tropical cyclones based on National Hurricane Center, Central Pacific Hurricane Center, and Joint Typhoon Warning Center Advisories. Atlantic storms Tropical Storm Philippe (AL17), Hurricane Rita (AL18) are at the top, East Pacific storms Hurricane Jova (EP10), Tropical Storm Kenneth (EP11) and Tropical Depression Max (EP13) are in the middle and West Pacific Storms Tropical Storm Damrey (WP17) and Typhoon Saola (WP18) are shown at the bottom.

The pressure vs. wind relationships for tropical cyclones have been re-evaluated using the last 15 years of tropical cyclone best track wind estimates and aircraft MSLP values to assess the relative importance of latitude, environmental pressure and tropical cyclone size. Both environmental pressure and tropical cyclone size are determined from numerical analyses and appear to have no dependency on the analysis used (NOGAPS, GFS, and NCEP-Reanalysis). Findings suggest that all of these factors can be used to reduce the scatter in the current pressure wind relationships. Larger and higher latitude storms produce lower MSLP for the same maximum wind speed. Environmental pressure is additive, so that storms occurring in a higher pressure environment have higher MSLP. Relationships were developed to estimated the wind from quality pressure observations and to estimate the pressure given a good estimate of the maximum 10-m, 1-minute sustained wind. These relationships can be utilized in operational tropical cyclone centers throughout the world and for reanalysis of past tropical cyclone events. Figure 3a shows the estimates of maximum wind speed based on the observed MSLP using this new method vs. the best track wind speeds for the 2005 Atlantic Hurricane Season through 8 Sept 2005. For comparison, Fig. 3b shows the wind speed estimate based on the Atlantic Dvorak pressure wind relationship vs. the observed best track value. Note the Katrina best track used was preliminary. Documentation of these methods has been prepared for publication.

Figure 3a

Figure 3b

Figure 3. Displayed is a comparison of tropical cyclone pressure vs. wind relationships. a) results of a recently developed relationship that given the MSLP predicts the maximum sustained wind given storm latitude, tropical cyclone size and environmental pressure. Cyclone size and environmental pressure are estimated from the NCEP GFS model. b) is the maximum wind predicted if the Atlantic Dvorak pressure vs. wind relationship is used given the MSLP. Pressures come from aircraft and dropsonde observations during the 2005 Atlantic Hurricane Season. Results are for independent cases.

A paper describing the statistical tropical cyclone wind radii prediction schemes used at the National Hurricane Center and the DOD Joint Typhoon Warning Center has been prepared for publication. Two models based on climatology and the persistence of initial conditions are described. One model makes use of a parametric vortex (DRCL) to make predictions while the other (MRCL) uses multiple linear regressions. Both produce remarkably similar results as shown in Figs. 4a,b for Tropical Storm Franklin on 23 July 2005 at 0000 UTC. The forecast intensities are listed on the figure at each forecast point valid for 0, 12, 24, 36, 48, and 72-h.

Figure 4a

Figure 4b

Figure 4. Forecasts of tropical cyclone wind radii associated with tropical Storm Franklin on 23 July 2005 produced by purely statistical forecast schemes based on a combination of climatology and the persistence of initial conditions are shown. Part a) 5-day forecasts made by the DRCL model, and b) the 3-day forecast made by the MRCL model. In both cases initial 34-kt wind radii are 40, 75, 0 and 0 nm in the NE, SE, SW, and NW quadrants, respectively. See text for model descriptions.

In order to account for changes in grib data storage implemented by NESDIS, code which converts Global Forecast System (GFS) model analyses from grib format to a packed ASCII format was updated. The output of the code is used in a program which generates a tropical cyclone genesis parameter. If the NESDIS server experiences problems, code is available to retrieve the GFS data from the National Weather Service server.

A 10-day rotating archive of McIDAS GRID files, containing selected fields from Global Forecast System (GFS) model analyses, has been created at RAMMB-CIRA. The files are being used for tropical cyclone research.

Atmospheric profiles from the ATOVS (Advanced-TOVS (Tiros Operational Vertical Sounder)) data are being used to analyze mid-latitude cyclones occurring over the eastern North Pacific. Temperature and moisture profiles from the current NOAA polar-orbiting satellites are gridded over the storms and their environment. The hydrostatic equation is then integrated downwards from 100 hPa, giving the height of various pressure levels, as well as the surface pressure. The 100 hPa heights from the NOGAPS (Navy Operational Global Atmospheric Prediction System) analysis are used as a boundary condition. The assessment of the accuracy of the technique is under way. Data from buoys, as well as dropsondes from the 2001 and 2002 PACJET (Pacific Land-falling Jets Experiment) field projects will be used to validate fields of temperature, water vapor mixing ratio, height, and surface pressure.

An article entitled, “Heavy Snowfall in the Midst of a Drought” by J.F. Weaver, which appeared in the fall issue of the CIRA Magazine, was re-written in partnership with Assistant Colorado State Climatologist, Nolan Doesken. It now appears with a companion piece on the climatology of Colorado heavy snowfall in the Winter 2003 issue (most recently published) of the Colorado Climate Center’s semi-annual magazine, Colorado Climate. The revised article, with improved graphics, is now entitled, “An Unusually Heavy Snowfall in North Central Colorado, or odd things that happen during severe droughts – a Meteorologist’s Point of View.” The issue can be viewed at:

http://www.cira.colostate.edu/ramm/KFIntranet/Publications/cc2003wy.pdf

GOES, MODIS, and AIRS data for the Reventador Volcanic eruption in Ecuador during November 3-5, 2002 have been added to the GOES-R Risk Reduction Activity database at:

http://www.cira.colostate.edu/ramm/KFIntranet/GOES-R_IPO/GOESR_IPO_case_study_database.html

The combined characteristics of the satellite’s high temporal resolution, high spatial resolution, and high spectral resolution will allow for more accurate volcanic ash detection for hazards mitigation.

The GOES-N Post Launch Test (PLT) Website has been launched (even though the satellite has not) at:

http://rammb.cira.colostate.edu/projects/goes_n/.

An e-mail list has also been started, to notify selected researchers of PLT information, which to date has revolved around the attempts to launch GOES-N, now set for no earlier than 6 October 2005.

Automated methods to collect 1-km AVHRR and MODIS imagery over tropical cyclones have been developed. Imagery is collected in a storm relative manner and remapped to a common projection. This data will be used to explore the possibility of new tropical cyclone applications as well as potential shortcoming of current techniques as GOES-R increase the spectral and temporal resolution of imagery over tropical cyclones.

Meteosat Second Generation (MSG) imagery data (11 channels, 3-km resolution, 15-minute temporal resolution) is being collected during the 2005 Atlantic Hurricane season. Data will be used to help better understand what additional information is available in the relatively high temporal/spectral frequency available from MSG

GOES, MODIS, and AIRS data for the Reventador Volcanic eruption in Ecuador during November 3-5, 2002 have been added to the GOES-R Risk Reduction Activity database at:

http://www.cira.colostate.edu/ramm/KFIntranet/GOES-R_IPO/GOESR_IPO_case_study_database.html

The combined characteristics of the satellite’s high temporal resolution, high spatial resolution, and high spectral resolution will allow for more accurate volcanic ash detection for hazards mitigation.

Improvements were made to the visible image products on Tropical RAMSDIS. The areal coverage of the large-area visible loops was changed to remapped areas so that there are no gaps in coverage in the Northern Hemisphere tropics from Africa west to Asia. The Meteosat-8/MSG-1 and GOES-9 products were changed to the combined visible/3.9 µm image product to provide nighttime continuity. All of the 4 km GOES and Meteosat-8/MSG-1 floater loops are now combined visible/3.9 micrometer images.

The software to generate land and ocean skin temperatures (and longwave temperature differences) has been upgraded to work on satellites and instruments other than the GOES Imager and Sounder. The skin temperature product and longwave temperature difference product can now be generated from the longwave bands of AVHRR, MODIS, and MSG/Meteosat. The skin temperature product compensates for atmospheric absorption to extrapolate longwave window temperatures for no atmospheric absorption. In addition, the software takes advantage of more recent McIDAS code than the previous version of the program.

Figure 1a

Figure 1b

Figure 1: Examples of MSG full-disk images for (a) land and ocean skin temperatures, color enhanced for warm values, and gray for cold values (clouds); and (b) longwave temperature differences, both generated from the longwave (10.8 µm) and dirty window (12. µm) bands. The skin temperature product gives estimated radiative temperatures for land and ocean surfaces. The temperature difference product highlights thin cirrus as darker values and super-adiabatic desert areas as lighter values.

In response to a request by Ken Pryor (NOAA/NESDIS), the experimental cloud-top 3.9 µm albedo product has been added to RAMSDIS Online http://www.cira.colostate.edu/RAMM/rmsdsol/main.html. A new color table was created for the cloud-top albedo product (Fig. 1), to better distinguish between slight variations in the low (1% to 3%) albedo values that characterize most cloud tops, as in the attached example. Recent research has shown that shortwave albedo is related to updraft strength and other thermodynamic parameters. A paper on this topic will soon be submitted to Monthly Weather Review.

Figure 1. Left-side of gray scale contains longwave window-band (10.7 µm) temperatures. Right-side of gray scale contains cloud-top shortwave albedos, for temperatures colder than -30ºC, mostly in the 1% to 3% range for this example that contains Hurricane Ophelia. Higher albedos only appear for the thinner outer bands of the hurricane.

Three abstracts were submitted and accepted to the AMS annual meeting in Atlanta, Georgia. The titles of the abstracts are “synthetic GOES-R and NPOESS imagery of mesoscale weather events,” “a technique for computing hydrometeor effective radius in bins of a gamma distribution,” and “analysis of a hook echo and RFD from a simulated supercell on 8 May 2003.”

A satellite-based method for estimating the winds in tropical cyclones has been adapted for use at high latitudes. In this method, temperature profiles are calculated from radiances from the Advanced Microwave Sounding Unit (AMSU) which flies aboard NOAA’s most recent polar-orbiting satellite series. Using the hydrostatic assumption and a 100-hPa height field from the GFS model as a boundary condition, the temperature profile is used to compute the height field as a function of pressure. A nonlinear balance equation is then solved for the stream function, from which the u and v components of the non-divergent wind may be calculated.

In order to develop the technique, AMSU data from NOAA-15 and NOAA-16, as well as radiosonde profiles from 20 stations north of 60 oN were collected from 2 – 17 December 2004. As a first step, the AMSU temperature retrievals were compared to collocated radiosonde data (Fig. 1). The biases typically were between -1 K and 1 K and the root mean square error (rmse) was generally about 2-3 K. Near the surface and the tropopause, the bias and rmse are greater. Although these areas generally pose problems for satellite retrievals, improvement will be sought by using the more sophisticated Advanced-TOVS (ATOVS) soundings. The ATOVS products are NESDIS’ operational polar-orbiting satellite retrievals which contain information from both the HIRS (High-resolution Infrared Radiation Sounder) and the AMSU-A instrument; the current retrieval technique uses only the AMSU-A instrument.

Fig. 1. Bias and root mean square error (rmse) as a function of pressure for the comparison of the satellite retrieval technique based on the AMSU-A instrument and collocated radiosondes. The number of matches at each level is given at the right.

AMSU and SSMI products for precipitable water and rain rate along with the 85 and 89GHz brightness temperature composites and SSMI winds can be found on the VISITview RAMSDIS Online site at:

http://hadar.cira.colostate.edu/vview/vmrmtcrso.html Enter a group name (i.e. weather) in the dialog box that appears.  Select any product labeled SSMI or AMSU from the list under “Select Page & click ‘Load Page.” Hit the Load Page button to display the loop.

These products are being used for live, interactive weather discussions between the US and many Central and South American and Caribbean countries. The weather briefings promote the enhanced use and understanding of satellite imagery and foster communication among many of the participating countries.

In trying to use the visible albedo concept to enhance true color images from MODIS, it was found that the increase in brightness obtained by correcting image pixels for non-nadir solar zenith angles has a very limited effect on images near local noon. Instead, contrast stretching of each of the three (red, green, and blue) bands can be used to create much more vivid enhanced true color images.

Figure 2a

Figure 2b

Figure 2: a) True-color image over parts of Spain, France, and Italy generated from MODIS red, green, and blue bands enhanced by correcting each pixel for non-nadir solar zenith angles. This image looks largely similar to an un-corrected true-color image, since the increase in visible brightness is only a few percent, and b) contrast-stretched “true-color” version of the MODIS image in 1a, generated by contrast-stretching the red, green, and blue bands before creating the three-color product. Colors are still true, just greatly enhanced. As an advantage, note the increased contrast of the ocean surface between sun glint and non sun glint areas.

Real-time Japanese MTSAT data are now available on a NOAA server. Attached are images of all 5 bands, similar to those on GOES-8-11, with the 12.0 µm band rather than the 13.3 µm band on GOES-12 onward. Note that the band numbering is different than for GOES, with the water vapor image as band-4, and the shortwave IR image as band-5. McIDAS 2005a is needed to use MTSAT data.

Figure 1: Near full-disk images of Japanese MTSAT bands 1 through 5 (shown in 1a-1e).

Figure 1a

Figure 1b

Figure 1c

Figure 1d

Figure 1e

Processing of the large sector U.S. climatologies continues on schedule.  Products completed include monthly large sector composites for June, July, and August, 2005.

Processing of wind regime products is on schedule.  Monthly wind regime composites from both channel 1 and channel 4 for May, June and July 2005 have been completed.  Combined monthly products have also been completed for these months and channels. 

A new collaborative effort has begun with Eureka’s National Weather Service (NWS) office Science and Operations Officer, Mel Nordquist.  Satellite cloud composites will be produced for every two hours over the Eureka CWA for the summer months, to see the general extent and movement of the marine stratus layer.  Future projects will stratify the composites according to parameters like cloud depth and look into burn-off rates.  So far, a sector over the Eureka CWA has been decided upon, and work is underway to set up the processing procedures.

J. Weaver continues to mentor a CSU graduate student working on a satellite/severe weather topic for her Master’s thesis. Rebecca Mazzur is one of Dr. Tom Vonder Haar’s students who has chosen as a reasearch topic the features described in, “Weaver, J.F., and D.T. Lindsey, 2004: Some frequently overlooked visual severe thunderstorm characteristics observed on GOES imagery – a topic for future research. Mon. Wea. Rev., 132:6, 1529-1533.” A PDF version of this article can be found at:

http://www.cira.colostate.edu/RAMM/KFIntranet/Publications/Comprehensive.HTML

The manuscript entitled, “Microscale Aspects of Rainfall Patterns as Measured by a Local Volunteer Network” by N. Doesken, J. Weaver and M. Osecky has been accepted by National Weather Digest contingent on a number of revisions. N. Doesken (Colorado Climate Center) continues to work on his portion of the reviewer suggestions.

D. Molenar is participating in the ongoing ORA IT Advisory Committee. The committee meets twice a month to provide guidance for future ORA IT requirements.

Brazil Project:

Nothing New to Report This Quarter.

Japanese Interaction:

A manuscript for the Journal of Applied Meteorology on the development of AMSU wind retrievals for tropical cyclones was accepted. This study was a collaborative project with the Japan Meteorological Agency (JMA) Meteorological Research Institute.

MITCH Reconstruction Project:

Nothing New to Report This Quarter.

RMTC Project:

GOES-8 imageryfor June through August 2005 were processed for the Regional Meteorological Training Centers (RMTCs) in Costa Rica and Barbados. The archives are being used to investigate cloud frequency during the rainy and dry seasons and detect local variations from year to year. The monthly cloud frequency composites for June – August 1997-2005 by 10.7 µm temperature threshold technique for Costa Rica are presented in Figure 1.

Figure 1. Monthly cloud frequency composites for June -August 1997-2005 by 10.7m m temperature threshold technique for Costa Rica.

A comparison of cloud frequency derived by temperature threshold of 10.7 µm imagery for June – August 1998 – 2005 for Barbados is shown in Figure 2.

Figure 2. Comparison of cloud frequency derived by temperature threshold of 10.7 µm imagery for June – August of 1998 – 2005 for Barbados .

The archived imagery also provides access to examples for use in satellite focused training efforts.

The Central America climatology web site has recently been updated for the months May through November 1998-2004 (http://rammb.cira.colostate.edu/research/climatology/central%5Famerica/). The transition from the drier to rainier period generally occurs in May and the transition from the rainier to drier period generally occurs in November.

The following web pages continue to provide on-line imagery in jpg format over Central and South America and the Caribbean.

http://www.cira.colostate.edu/RAMM/rmsdsol/RMTC.html

http://www.cira.colostate.edu/RAMM/rmsdsol/COS.html (for imagery over Costa Rica and Barbados)

This site continues to display satellite precipitation estimates and fire products:

http://www.cira.colostate.edu/ramm/sica/main.html

SICA Project:

The project officially ended on December 31, 2001, but a web page displaying satellite precipitation estimates and fire products continues to operate at:

http://www.cira.colostate.edu/ramm/sica/main.html

The site continues to be useful as a backup for the imagery when the server in Costa Rica goes down.

The following web pages continue to provide on-line imagery in jpg format over Central and South America and the Caribbean.

http://www.cira.colostate.edu/RAMM/rmsdsol/RMTC.html

http://www.cira.colostate.edu/RAMM/rmsdsol/COS.html (for imagery over Costa Rica and Barbados)

This site continues to display satellite precipitation estimates and fire products:

http://www.cira.colostate.edu/ramm/sica/main.html

Full recovery of data lost during a system failure is complete. New backup and archive procedures have been implemented based on lessons learned.

The CIRA Linux cluster is being revamped. It was determined that RAMM Linux systems would continue to be independently administered by RAMM staff due to software incompatibilities.

Student hourlies are writing tropical and severe storm data ingest to DVD on a daily basis.

Meetings with all RAMMB staff to discuss FY05 performance plans have been completed.

M. DeMaria participated in the first meeting of the NOAA committee appointed to finalize the new procedures for re-competing the cooperative institutes. The dates for the first re-competition will be finalized and a first draft of the CI handbook will be completed by the end of August. P. Menzel also participated.

A hardware support agreement for the HP3000 series machine was procured. HP will, however, no-longer support the HP3000 systems past January 30, 2006

A dial-up account with the EarthLink was renewed for another 12 months. The dial-up accounts are mainly used when scientists are on travel.

The RAMMB IT group completed installing image backup software on all RAMMB members’ desktop systems. This software will automatically create routine image backups of hard drives that will facilitate the prompt rebuilding of a system when a catastrophic hard drive failure occurs, and will help ensure the safety of each members’ data.

Visitors:

Meetings, Conferences, Workshops:

AMS: American Meteorological Society

AMSU: Advanced Microwave Sounding Unit

AWIPS: Advanced Weather Interactive Processing System

CAMEX: Convection and Moisture Experiment

CG: Cloud to Ground

CIMSS: Cooperative Institute for Meteorological Satellite Studies

CIRA: Cooperative Institute for Research in the Atmosphere

COMET: Cooperative Program for Operational Meteorology, Education, and Training

CONUS: Continental U.S.

CoRP: Cooperative Research Programs

CSU: Colorado State University

EUMETSAT: European Meteorological Satellite

FEMA: Federal Emergency Management Agency

FTP: File Transfer Protocol

GIMPAP: Goes I-M Product Assurance Plan

GOES: Geostationary Operational Environmental Satellite

HRD: Hurricane Research Division

IR: Infrared

JHT: Joint Hurricane Transition

LAPS: Local Analysis and Prediction System

LES: Lake-Effect Snow

McIDAS: Man Computer Interactive Data Access System

MODIS: Moderate Resolution Imaging Spectroradiometer

NASA: National Aeronautics and Space Administration

NCAR: National Center for Atmospheric Research

NDIC: Natural Disaster Information Cards

NESDIS: National Environmental Satellite Data Information Service

NHC: National Hurricane Center

NIDS: NEXRAD Information Dissemination Service

NOAA: National Oceanic and Atmospheric Administration

NWS: National Weather Service

NWSFO: National Weather Service Forecast Office

OM: Office of Meteorology

ORA: Office of Research and Applications

PACJET: Pacific Landfalling Jets Experiment

POES: Polar-orbiting Operational Environmental Satellite

POP: Product Oversight Panel

RAMMT: Regional and Mesoscale Meteorology Team

RAMS: Regional Atmospheric Modeling System

RAMSDIS: Regional and Mesoscale Meteorology Team Advanced Meteorological Satellite
Demonstration and Interpretation System

RMTC: Regional Meteorological Training Center

ROL: RAMSDIS Online

SAB: Satellite Applications Branch

SHIPS: Statistical Hurricane Intensity Prediction Scheme

STIPS: Statistical Typhoon Intensity Prediction Scheme

SOCC: Satellite Operations Control Center

SOO: Science Operations Officer

SRSO/RSO: Super Rapid Scan Operation/Rapid Scan Operation

STAR: Office of Satellite Research and Development

STEPS: Severe Thunderstorm Electrification and Preciptation Study

TPC: Tropical Prediction Center

USWRP: United States Weather Research Program

UTC: Universal Time Coordinated

VISIT: Virtual Institute for Satellite Integration Training

WMO: World Meteorological Organization

WV: Water Vapor