The primary objective of the Techniques Development Program is to develop analysis and forecast techniques which, when implemented, will help improve forecast accuracy and service to the wide range of users of NWS products. These techniques are implemented on NOAA's computer system, when appropriate, and guidance products disseminated via AFOS, facsimile, or other NWS distribution systems. Techniques are produced for basic weather elements used in public and aviation forecasts, such as temperature and visibility. Also, special emphasis is given to marine-related forecasts and to those forecasts especially associated with mesoscale processes. For many synoptic-scale forecasts, the output of operational numerical models is used to produce forecasts of weather elements of interest to users. When dealing with forecasts of shorter time and space scales, more use is made of data sets rich in information on those scales; for example, hourly and automated surface reports and radar, satellite, and profiler data. For marine-related forecasts, numerical and statistical models relate elements of interest, such as storm surge, to atmospheric analyses and forecasts.

OBJECTIVE WEATHER PREDICTION PROJECT(P. Dallavalle)

Short-Range Weather Forecasting Task(Dallavalle):   Development of the new MOS-2000 system continues. We're currently deriving equations to predict wind speed and direction; maximum/minimum (max/min) temperature; hourly temperature; hourly dew point; and the probability of precipitation, precipitation amount, precipitation type, cloud amount, and ceiling height. These new forecast equations are based on output from the Aviation (AVN) run of NCEP's Global Spectral Model (GSM). TDL's AVN archive began in April 1997 and continues to the present. Thus, for both the warm season (April - September) and cool season (October - March) development, we have approximately 2 years of model output. To expand the developmental sample somewhat and to enhance the consistency between the warm and cool season equations, we've generally added 15 days from the adjacent season, whenever possible. Thus, for instance, our developmental sample for the 1998 warm season begins on March 17, 1998, and ends on October 15, 1998.

Up to this time, we have been primarily testing warm season equations developed for approximately 335 stations in the contiguous U.S., Alaska, Hawaii, and Puerto Rico. Results from testing the wind equations for both the 0000 and 1200 UTC forecast cycles on a sample of independent data showed that the AVN MOS provided better guidance at every projection compared to the older MOS system based on the Nested Grid Model (NGM). Note that the AVN MOS wind guidance is valid every 3 hours from 6 to 72 hours after initial model time. In terms of the mean absolute error, for forecast projections from 6 to 60 hours after 0000 UTC, the AVN MOS wind speed guidance improved relative to the NGM MOS by an average of 7.1 % (or 0.2 knots). For wind direction, the number of AVN MOS wind direction forecasts (when the observed wind speed was 10 knots or greater) with errors of less than 30 averaged nearly 4 percentage points higher than the NGM MOS guidance. For the temperature guidance during the warm season, the skill of the AVN MOS system was comparable to that of the NGM MOS system at most projections; beyond 48 hours, the AVN MOS system gener-ally had greater skill. The temperature results varied somewhat from region to region. The AVN MOS system to predict dew point was generally more accurate than the NGM MOS system, regardless of region. Preliminary results of testing AVN MOS equations to predict the probability of total cloud amount similarly indicated improvement relative to the NGM MOS guidance. Initial results of testing AVN MOS equations to predict the probability of precipitation and precipitation amount indicated that the forecasts from the NGM and AVN MOS system were quite similar in terms of overall skill. Some of these latter results are discussed in a paper entitled "New AVN-based MOS Precipitation Forecasts: Taking the Primary Statistical Precipitation Guidance to the Threshold of the Medium Range" by E. Lenning and M. Antolik which will be presented in September at the American Meteorological Society (AMS) 17th Conference on Weather Analysis and Forecasting. We're now completing development of the final warm season equations for wind, temperature, and dew point, and are turning our attention to development and testing of cool season equations.

At the April meeting of the Committee for Analysis and Forecast Techniques Implementation (CAFTI), we were asked to convert the NGM MOS system to run on NCEP's new IBM SP computer. CAFTI requested this conversion to allow both NWS and private-sector forecasters to have approximately 1 year during which the guidance from the new AVN MOS and the NGM MOS systems would overlap. From approximately April 2000 to April 2001, the forecast community will be able to judge the performance of the two statistical systems. We are currently assessing the software that will need to be modified. In addition, efforts to build the MOS-2000 software for operations on the IBM are underway. Details of the file systems and identifiers are being worked out, and modules to pre-process model forecasts and post-process MOS forecasts have been designed.

Medium-Range Weather Forecasting Task(M. Erickson):   Development of new medium-range forecast equations to predict temperature and the probability of precipitation amount continues. Final experimental forecast equations to predict the daytime max and nighttime min temperature have been developed for the warm season (April - September). Verification of test forecasts valid 24 to 192 hours after 0000 UTC have shown that the accuracy of the experimental forecasts matches or exceeds that of the operational MRF MOS max/min forecasts in terms of mean absolute and root mean square error. Improvements over the operational system are larger at earlier projections, and the two systems have approximately equal scores at the later projections. Experimental equations to produce probabilistic quantitative precipitation forecasts (QPF) for categories > 0.01, 0.25, and 1.00 inches of liquid-equivalent precipitation over a 24-h period were also developed for the warm season. Adjustments are still being made to the statistical process to account for the small sample of heavy precipitation events, but preliminary verifications in terms of improvements over climate in the Brier Score indicate we can produce skillful forecasts of > 0.01 and 0.25 inches in the medium-range. As expected, the skill of the guidance decreases rapidly with increasing projection during the warm season when most of the precipitation events are convective in nature. Work will begin on development of the cool season equations next quarter.

A paper entitled "Updated MRF-based MOS Guidance: Another Step in the Evolution of Objective Medium-Range Forecasts" by M. Erickson and K. Carroll documents our plans and development of the new MRF-based MOS package. In addition, M. Shirey and M. Erickson wrote "Statistical Quantitative Precipitation Forecasts Based on the Medium Range Forecast Model" to describe the QPF system in the medium-range. Both papers will be presented at the AMS 17th Conference on Weather Analysis and Forecasting.

National Verification Processing Task(V. Dagostaro):   Preliminary verification results were generated from unedited AFOS-Era Verification (AEV) data for the 1998 warm season and 1998-99 cool season. For the warm season, scores were generated for max/min temperature, probability of precipitation, cloud amount, ceiling height, and visibility for 98 stations in the contiguous U.S. For the cool season, scores were generated for the weather elements listed above and for precipitation type, wind direction, and wind speed for approximately 103 stations in the contiguous U.S. Also for the cool season, scores for snowfall forecasts were generated for 22 stations for which snowfall amount observations were available. The preliminary results were condensed into tabular form for distribution to the Office of Meteorology (OM) and the Regional Scientific Services Divisions. In addition, special verifications were generated for ceiling height, visibility, and wind speed for about 98 stations for an extended cool season (October 1997 - March 1998 and October 1998 - February 1999) and the 1998 warm season. Stations were divided into two regions, namely, coastal or interior, based on proximity to the oceans or Great Lakes. Results were provided to OM.

We continued our effort to convert the AEV data processing system to run on UNIX-based platforms. Verification data for March and April 1999 were converted to the MOS-2000 format. Testing of software to quality control the AEV forecasts and observations is nearing completion. Finally, we prepared a proposal to modify current MOS-2000 software to label and store verification scores in standard MOS-2000 format.

In support of the modernization effort, we've continued to monitor and archive test verification data processed by AWIPS software. Because AEV data transmitted from AWIPS are now identified by using standard WMO headers, and data transmitted from AFOS continues to use non-standard headers, our data archiving software was modified to handle both types of headers. The modified data archiving software was implemented on the Cray mainframe in May.

Severe Weather Prediction Task(R. Reap):   The effort continues to develop new MOS thunderstorm and severe local storm probability forecast equations from Eta model predictors and archived thunderstorm and severe local storm predictands. Efforts to develop similar forecast equations from the AVN are also underway. The Eta-based MOS forecast equations will predict the probability of thunderstorms for 12- and 24-h periods out to 60 hours after both 0000 and 1200 UTC. We currently are planning to output the guidance on a 48-km grid covering the contiguous U.S. In contrast, the AVN-based MOS forecasts of thunderstorms and severe thunderstorms will be valid for 6-, 12-, and 24-h periods ending approximately 72 hours after both 0000 and 1200 UTC. The AVN-based guidance will be available for individual sites in the contiguous U.S. Initial plans for the AVN-based system are documented in a paper entitled "AVN-based Statistical Forecasts of Thunderstorms and Severe Thunderstorms for the Contiguous U.S." by K. Hughes. This paper will be presented at the AMS 17^th Conference on Weather Analysis and Forecasting.

LOCAL TECHNIQUES DEVELOPMENT PROJECT (S. Smith)

0-3 Hour QPF and Severe Weather Task(D. Kitzmiller):   Probabilistic 0-3 hour forecasts for rainfall and lightning, and categorical rainfall amount forecasts, are now being generated 24 hours a day in real time on the GDP system. Forecast graphics and documentation are available for review in TDL through an internal URL.

Two experiments were undertaken to test potential improvements to the 0-3h rainfall forecast algorithm. The first involved the use of pattern matching among earlier pairs of radar reflectivity images to derive extrapolation vectors for radar echoes. This is a possible enhancement to the current method of using the

700-500 mb mean wind vector as an estimate of echo velocity. Results indicated that there was no improvement, and sometimes slight degradation, in the forecasts. Another experiment, involving regionalization of the 0-3h precipitation probability equations, is still underway.

Arrangements for operational implementation of the rehosted national radar mosaic and AUTOROB processes continue to move forward, including meetings between representatives from TDL, OSO, and OM to discuss issues including dissemination format and requirements for an operational workstation platform. Delivery of this workstation to OSO is expected during the summer.

Thunderstorm Identification and Forecasting Task(S. Smith):   The AWIPS SCAN DDT team continued work in designing and prototyping the functionality of the National Severe Storms Laboratory's (NSSL's) Warning Decision Support System as well as the SCAN CWA Threat Indices for Severe Weather and Flash Floods for SCAN 2.0.

Training on SCAN 1.0 and an update on SCAN development activities was given at the CR SOO sub-regional in Chicago. A talk on planned flash flood monitoring in SCAN was given at the 2^nd NWS QPE workshop in Boulder. A Seminar entitled "A comprehensive approach to improving NWS warning operations and services" was presented at NWSHQ.

The 1999 Field Test/Demonstration of SCAN began on May 1 at the Washington D.C.-Baltimore Forecast Office in Sterling, Virginia. New prototypical forecaster decision-assistance applications developed by the National Severe Storms Laboratory and the National Center for Atmospheric Research were installed in early May.

A new Flash Flood Monitoring and Prediction software development team comprised of members of the Techniques Development Lab, the Hydrologic Research Lab and the National Severe Storms Lab was formed and began regular meetings. The focus of team is on the implementation of AWIPS Build 5 flash flood monitoring and prediction requirements.

An OSD/OM-sponsored workshop was held on April 28 & 29 in Silver Spring to begin the process of defining the requirements and design for SAFESEAS. The workshop was attended by representatives from the Regions, NCEP, OM, OSD, NOS, and OAR. The participants reviewed current marine forecasting methodologies, guidance products, and data sets used in issuing the operational marine products in AWIPS and outlined how SAFESEAS should serve initially as a marine hazard monitoring function using current and near-future AWIPS data sets.

Local AWIPS MOS Program Task(J. Ghirardelli):   Site-Specific equations, thresholds, weight files, and location files were created and delivered for the final 11 AWIPS sites in April. Among these sites were the two new AWIPS sites, Key West and

Caribou, for which LAMP was configured and tested. The files were delivered on time to PRC and have been put under the AWIPS configuration management system.

Enhancements of the methodology in which LAMP matches station identifiers with the current observations have been completed this quarter. The LAMP group has been able to implement a new station dictionary in which old call letters are matched with their corresponding new identifiers. Subsequently, a c-shell script has been written to be included in the AWIPS master installation scripts for build 4.3. This script will automatically update LAMP's site-specific files for this important modification.

Work continued on converting the LAMP code to flexible, user-specified grid spacing and dynamic memory allocation. With the advent of flexible grid spacing, field sites will be able to specify finer grid resolutions in a control file. This capability is intended to capture more observations in data-rich regions than the current grid spacing allows, which will yield better LAMP forecasts.

Software integration of QPF LAMP with non-QPF LAMP has been finished. All of LAMP's smart scripts have been amended to include calls to all QPF codes. Successful testing of the non-QPF LAMP smart scripts with the inclusion of QPF software have been progressing smoothly.

Heavy Precipitation Forecasting Task(J. Charba):   Maintenance and development of the LAMP QPF system continued for the operational AWIPS baseline as well as national prototype system which provides web-accessible experimental products to the general public.

MARINE ENVIRONMENTAL PREDICTION PROJECT(W. Shaffer)

Hurricane Storm Surge Forecasting Task(W. Shaffer):   Levee heights for the Lake Pontchartrain/New Orleans SLOSH basin were updated with the latest elevation surveys. The New Orleans forecast office met with representatives from the U.S. Army Corps of Engineers and the local levee boards to acquire the latest survey data that they had available. Many of the changes were increased elevations due to closing in gaps that were previously noted. This updated database will be used for SLOSH this hurricane season for any hurricane threatening the New Orleans area.

We distributed CD-ROM copies of the SLOSH display program to the emergency managers that attended this past year's FEMA hurricane course at NHC and to all WCM's at forecast offices along the East and Gulf Coast. This program, written in Tcl/Tk, runs on PC's under Windows or on our HP computers running HP-UX. Displays from both operating systems will be virtually identical. This program is scheduled to be included in AWIPS build 5.0.

Extratropical Storm Surge Forecasting Task (J. Chen):   We are statistically analyzing the extratropical surge model's characteristics using data from the past three winter-spring seasons, comparing model forecasts to National Ocean Service water level gage observations. We selected four gages from the mid-Atlantic Bight to the Gulf of Maine (Boston, Massachusetts; Sandy Hook, New Jersey; Lewes, Delaware; and Chesapeake Bay Bridge Tunnel, Virginia) and one gage in the Gulf of Mexico (Galveston Pleasure Pier, Texas.) With the exception of Boston, each of these gages is in the NOS PORTS system. The TDL extratropical model's output is used routinely as an entrance condition for NOS's regional bay models.

The NOS gage observations are filtered with a 30-h low-pass filter to remove the astronomical tide. The RMSE for the Atlantic gages ranges from 10-15 cm and about 10 cm for Galveston. One difficulty we have is determining the local departure from mean sea level. Our model computes only the meteorologically driven portion of water level changes and cannot account for such departures. We are investigating strategies to help resolve this problem. One possibility is to examine previous gage observations to determine this discrepancy. This will involve placing selected NOS data on to NOAA's mainframe computers where the model is run.

Coastal Wave Forecasting Task(C.-S. Wu):   We are continuing to develop a two-dimensional hurricane wave model, incorporating a deep water ocean wave model and driving it with winds from the SLOSH parametric wind field. This model gives significant wave heights and periods over the hurricane storm area. Numerical modeling results were produced for hurricanes Opal (1995) and Fran (1996). We are comparing the model parameters to hurricane wave data collected by the National Data Buoy Center.

Dr. Wu was invited by the Central Weather Bureau of Taiwan to give a keynote lecture on recent advances in wind-wave modeling. Dr. Wu also collected a series of wave and surge observations around the Taiwan coast during recent typhoons. The wave set-up data collected by the pressure gages at Duck, North Carolina, was retrieved in preparation for verifying the SWAN coastal wave model developed in Delft, Netherlands. The nearshore coastal bathymetry around the Panama City, Florida, coast is being prepared for modeling the shallow water wave transformations.