OF THE 2003 WINTER STORM RECONNAISSANCE PROGRAM
By taking supplemental adaptive observations over the northeast Pacific ocean
OBSERVING PLATFORMS USED:
15-20 dropsondes per mission released by NOAA G-lV (based in Honolulu, Hawaii, approximately 6 flights) and USAF C-130 (based in Anchorage, Alaska, approximately 10 flights) aircraft
DURATION OF PROGRAM:
First possible flight centered around 00Z January 18, 2003; program is expected to end March 13, 2003. C-130s will be available between DD Mon - DD Mon; G-lV will be available between 18 Jan - 13 March
All adaptively taken data will be used in operational analysis and forecast products by major NWP centers, including NCEP
EVALUATION OF DATA IMPACT:
By comparing operational analyses/forecasts with those from a parallel analysis/forecast cycle from which all adaptively taken data will be removed
NEAR REAL TIME EVALUATION RESULTS:
Expected to appear on the EMC WSR2003 web page
On average a 10-20% reduction in largest rms forecast errors for preselected weather events. Errors for individual events can be reduced by as much as 60-80%.
See related papers listed in Reference section of EMC Targeted Observations Project and Reference section of Global Ensemble Forecasting web page, a recent review paper, and the WSR99 and WSR00 and the National Winter Storms Operations Plan web pages
FUNDING PROVIDED BY: NWS, NOAA/OAR; G-lV flight hours provided by the NOAA Aircraft Operations Center.
TARGETING METHOD DEVELOPED BY: C.H.Bishop and S.J.Majumdar of Penn State University, in collaboration with EMC personnel.
COORDINATION: Naomi Surgi
COLLABORATORS: Mel Shapiro, Marty Ralph
FOR THE 2001 WINTER STORM RECONNAISSANCE PROGRAM
Potential societal impact and amount of forecast uncertainty associtated with individual forecast weather events (precipitation, wind, etc) over the continental US, including Alaska
Verification time (yyyymmddhh) and center location (lat/lon) of 1000 km radius verification region for which forecast is to be improved
FLIGHT PLANNING. Because for proper aviation planning flight requests have to be issued 24 hours in advance of take-off, flight planning usually takes place 36-48 hours in advance of the actual flights.
OUTLOOK. For general planning purposes, the flight facilities also require a general outlook for the second day (i. e., whether a flight is expected or not). To prepare such an outlook, sensitivity calculations need to be run 60-72 hours before flight time.
FORECAST TIME WINDOW. The time elapsed between observation time and verification time. This is equal to the lead time of the forecast that the data collected in the future is to improve.
GEOGRAPHICAL LOCATION. Because it takes more time for the impact of the data to reach the eastern part of the US than the western areas or Alaska, the time window will necessarily be longer for verification regions defined over the eastern US. Given observations over the northeastern Pacific, the time window over the western US and Alaska will typically be between 24 and 48 hours, while for the eastern US it will be between 48 and 96 hours.
FORECAST LEAD TIME:Flight
planning/Outlook lead time plus forecast time window. Typically the forecast
lead time for case selection will be in the following ranges:
WEST COAST & ALASKA: 60-120 hours.
EAST COAST: 84-144 hours.
NOTE. Most of the time, the same or similar cases considered in the previous day's outlook planning will be selected (then with a 24-hour shorter lead time) next day again, and the sensitivity calculations will be repeated for final flight planning, using new ensemble data.
OBJECTIVE GUIDANCE PRODUCTS:
Beyond general forecast material, the following, ensemble-based objective guidance products can be used for the identification of forecast weather events associated with large uncertainty and large societal impact:
ENSEMBLE MEAN AND SPREAD. For Mean Sea Level Pressure and 250 hPa height fields for the NCEP ensemble:
PROBABILISTIC QUANTITATIVE PRECIPITATION FORECASTS. PQPF forecasts of 24-hour accumulated precipitation for different thresholds:
REALTIVE MEASURE OF PREDICTABILITY. 500 hPa height ensemble mean forecast with a measure of predictability and associated probabilistic forecast:
INTERCOMPARISON OF ENSEMBLE MEANS FROM DIFFERENT CENTERS.
Each selected feature is listed on a separate line in the order of increasing lead time:
ABS. PRIORITY VERIF. TIME VERIF. REGION DESCRIPTION
PRIORITY (High, Medium or Low, considering severity of event and available observational resources. Not every day are there high or medium priority events.)
VERIFICATION TIME (yyyymmddhh)
VERIFICATION REGION (lat/lon for 1000km radius area; if more than one area, listed on separate lines, from west to east)
DESCRIPTION OF WEATHER EVENT/NATURE OF UNCERTAINTY (in few words)
FORECASTER INPUT. WFO offices should contact their focal point within their region with their request. The focal points from the NWS Regions and NCEP Service Centers will then provide their input to the SDM desk at NCEP/NCO.
CENTRAL COORDINATED LIST. SDM prepares a final prioritized list of the selected cases.
SDM expects to receive the requests from the Regions and NCEP Service Centers by 9 am EST.
Regional focal points and NCEP Service Centers should send an e-mail with their request to email@example.com.
301-763-8298 (or 301-763-8000/ext. 7361)
To identify areas over the northeast Pacific from where adaptively taken data can have the largest impact on forecast quality in the preselected verification region at the verification time.
Based on the use of nonlinear ensemble forecasts generated operationally on a daily basis at NCEP and ECMWF. Ensemble members are linearly combined in such a way that their variance is reduced at observation time over the observational area. The same linear combination is used at verification time to see where the variance in the transformed ensemble is reduced. All possible predesigned flight tracks are considered and the one where the dropsondes are expected to reduce forecast error variance at verification time within the verification region most is selected.
Beyond preparing flight requests for flights taking place the next day, an outlook for the second day (i. e., whether a flight or no flight is expected with the G-lV and/or C130) also has to be prepared.
For the request of SDM the IBM opertators release the job to compute the most sensitive areas/flight tracks corresponding to the requested forecast cases. Based on the evaluation of the sensitivity results SDM makes a decision whether to fly and if so which flight track(s) to use.
Requests for flights centered around 00Z the next day have to be prepared and transmitted to CARCAH by 1:30 pm EST (18:30 Z the day before flight takes place, more than 24 hours in advance of take-off.) The outlook for the second day have to be transmitted at the same time.
Sdm@noaa.gov, 301-763-8298 (or 301-763-8000/ext. 7361)
Zoltan.Toth@noaa.gov, (301) 763-8000/ext. 7268
Out of Honolulu, Hawaii, by NOAA/AOC, contact person is Jack Parrish
813 833-3275, firstname.lastname@example.org
Out of Anchorage, Alaska, by USAF Reserve, contact person is Valerie Hendry
email@example.com, (305) 229-4474
Back to WSR2003 page