Download - 2011-2012 HPC Winter Weather Desk Operations and 2011 and 2012 Winter Weather Experiments
2011-2012 HPC Winter Weather Desk Operations and 2011 and 2012 Winter Weather
Experiments
Dan Petersen Winter weather focal point
with contributions from Keith Brill, David Novak, and Mike Musher
Presentation Goals
• Recent changes in WWD product suite
• HPC WWD verification
• 2011/2012 HPC Winter Weather Experiments
2010-11 WWD Changes2010-11 WWD ChangesExpand Probabilistic Snow and Ice Forecast SuiteExpand Probabilistic Snow and Ice Forecast Suite
Combine HPC deterministic forecast with model/ensemble forecasts to derive forecasts for probabilistic snowfall (1, 2, 4, 6, 8, 12, 18”) and ice (freezing rain 0.01, 0.10, 0.25, 0.5”) accumulations
2011-12 WWD Changes2011-12 WWD Changes
http://origin.hpc.ncep.noaa.gov/wwd/internal/gisproducts.php
WWD accumulation graphics on our internal page are now available WWD accumulation graphics on our internal page are now available in 2 GIS formats, KML (for Google Earth) and shapefilesin 2 GIS formats, KML (for Google Earth) and shapefiles
Current forecast and archive of prior forecasts are now available at Current forecast and archive of prior forecasts are now available at
2011-12 WWD Changes2011-12 WWD Changes• 48 hour snowfall and freezing rain accumulation
probabilities Snowfall probabilities
Freezing rain
probabilities
http://www.hpc.ncep.noaa.gov/pwpf/wwd_accum_probs.php
2011-12 2011-12 WWD Changes Changes
UKMET added to the accumulation UKMET added to the accumulation blender as a QPF optionblender as a QPF option
HPC Winter Weather Desk 2010-11 Verification
HPC Deterministic Snowfall ForecastHPC Deterministic Snowfall ForecastEast of the RockiesEast of the Rockies
Automated Superensemble: 0.8*(SREF members, GFS, NAM, ECMWF, ECMWF mean,CMC) + 0.2*(GEFS mean)
•All 4” and 8” metrics were better than last year.•All 12” metrics were worse than last year.
•Day 1 continues to be difficult to improve upon (right)
HPC Deterministic Snowfall HPC Deterministic Snowfall ForecastForecast
• WWD forecasts have a high bias, especially for 12”(ideal bias is 1, less than one would be
a low bias)
East of the Rockies
Verification of Day 2 forecast for February 2, 2011:
Final Human Forecast Chosen Blend
Auto Superensemble Observed
HPC Experimental Probabilistic Snowfall
•Including human deterministic forecast in calculation of product makes positive improvement at all thresholds (Good!!)
•Probabilistic skill for thresholds < 6”
•Difficult to improve upon sample climatology above 6”
-HPC is mode-Spread from
21 SREF+GFS+NAM+CMC
HPC Legacy Probabilistic Snowfall
•Degradation from last year•Benchmark likely improved•Increased temporal resolution of Snow-liquid Ratios•Human have too high of probabilities, especially for larger thresholds•Moderate and High risk areas are either too big and/or miss location
Day 1 WWD Verifying frequency
4,8,12” events forecast more frequently than observed, therefore high bias and
overconfident forecasts
HPC Legacy Probabilistic Snowfall
HPC Legacy Probabilistic Snowfall
High bias
Low bias
Day 3 WWD Verifying frequency
4,8,12” events forecast more frequently than observed, therefore high bias and
overconfident forecasts
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2010-11 Verification of HPC low 2010-11 Verification of HPC low tracks tracks (position at each forecast hour)(position at each forecast hour)
Lowest errors: Blend of the gfs+ecmwf 36-72hr
Among the models: UKMET/ECMWF best >48 h
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Summary-Verification
• Winter Weather Desk (WWD) provides skillful deterministic snowfall forecasts
• WWD categorical probabilistic forecast edits did not improve upon most accumulation thresholds, so fewer edits will be done this year to the automated multi-model/multi-ensemble probabilities
• Including the human’s deterministic forecast improves the continuous probability forecasts
Freezing rain continuous probability forecasts www.hpc.ncep.noaa.gov/pwpf_24hr/wwd_24hr_probs_zr.php
• 2011-12 Expansion of continuous probabilistic snow and ice forecasts to include 48 hour totals (event perspective)
• UKMET has been added to suite of available models in forecast
Heavy snow continuous probability forecastswww.hpc.ncep.noaa.gov/pwpf_24hr/wwd_24hr_probs_sn.php
Summary2011-12 plans and references
QPF archive
http://www.hpc.ncep.noaa.gov/archives/qpf/get_qpf_images.php
Gridded continuous probability forecasts can be obtained at
HMT-HPC Winter Weather ExperimentHMT-HPC Winter Weather Experiment
•14 participants (WFO, SPC, AWC, HPC, EMC, ESRL, and COMET)
•Can high-resolution models improve Day 1 forecasts of precipitation type and amount?
•Can we better quantify and communicate winter weather uncertainty for Day 1-2 forecasts?
Jan 10 – Feb 11, 2011
Goals
Participants
Approach•Create snow and ice accumulation forecasts using experimental guidance
•Write “confidence discussion”
•Subjectively evaluate experimental guidance
Winter Weather ExperimentWinter Weather ExperimentJan 10 – Feb 11, 2011Jan 10 – Feb 11, 2011
Day 1 Day 2
HRW-ARW x
HRW-NMM x
NMMB nest x x
NAM Rime Factor x x
ECMWF snow x x
SREF x x
HPC Superensemble
x x
Experimental Guidance Activities24 hr accumulated snow and ice forecasts for Day 1&2
Forecast Confidence Discussion
Model evaluation of precipitation type and amounts
Full detailed report with recommendations at: http://www.hpc.ncep.noaa.gov/hmt/HMT_HPC_WWE_Summary_Final.pdf
Winter Weather Experiment ResultsWinter Weather Experiment Results
HRW-NMM ObservedHRW-ARWExperimental NAM
Can high-resolution models improve Day 1 forecasts of precipitation type and amount?
Pros: •Improved orographic precipitation, lake effect
•Visualizing temporal evolutions
•Providing unique fields (simulated reflectivity).
Cons:•Overall amounts not superior to operational
Analysis courtesy WFO Tulsa OK
New Oklahoma All-Time Record 24-hour Snowfall:
27" in Spavinaw, OK February 9, 2011
Comparison of analyzed 24 hr snowfall vs model 36 hr forecasts from 00z 09 Feb 2011
Analysis and
forecast ending
time 00z 10 Feb 2011
Observed snowfall 12km NAM forecast
HPC superensemble ECMWF forecast
Comparison of analyzed 24 hr snowfall vs model 36 hr forecasts from 00z 09 Feb 2011
Observed snowfall
WRF NMM forecast
New NAM forecast
WRF ARW forecast
Analysis and
forecast ending
time 00z 10 Feb 2011
2012 Experiment Plans 2012 Experiment Plans
Experiment Questions•What added benefit will storm scale ensembles provide for winter
weather forecasting?
•Is the new SREF system an improvement over the operational system?
•How can forecasters add value to probabilistic winter weather forecasts?
•How can ensemble clusters be used in the forecast process?
•How can awareness of societal impacts improve forecast and decision support services?
Jan 9 – Feb 10 2012
2012 Experiment Plans 2012 Experiment Plans
Provider Dataset Projection Notes
EMC Parallel SREF (20-26 km)
87 h Pre-implementation version of the new SREF
AFWA 10 member 4 km storm scale ensemble
54 h Central and Eastern U.S. domain
NOAA HMT West 9 km 9 member ensemble
72 h California/Nevada domain
HPC Superensemble (SREF+ deterministic runs)
84 h BENCHMARK
EMC Operational SREF 87 h BENCHMARK
Datasets
Jan 9 – Feb 10 2012
Questions or comments?
HPC Forecast Operations desk
(301) 763-8201
18z 26 Jan 2011 sea 18z 26 Jan 2011 sea level fronts/pressureslevel fronts/pressures
06z 27 Jan 2011 sea 06z 27 Jan 2011 sea level fronts/pressureslevel fronts/pressures
00z 27 Jan 2011 sea 00z 27 Jan 2011 sea level fronts/pressureslevel fronts/pressures
12z 27 Jan 2011 sea 12z 27 Jan 2011 sea level fronts/pressureslevel fronts/pressures
Comparison of analyzed 24 hr snowfall vs model 36 hr forecasts from 12z 27 Jan 2011
Analysis and
forecast ending
time 00z 28 Jan 2011
Observed snowfall
WRF ARW forecast
New NAM forecast
WRF NMM forecast
Observed snowfall 12km NAM forecast
ECMWF forecast HPC superensemble
Comparison of analyzed 24 hr snowfall vs model 36 hr forecasts from 12z 27 Jan 2011
Analysis and
forecast ending
time 00z 28 Jan 2011
27-28 Jan 2011 Event analysis from WFO New York ,NY
• WFO input used to modify HPC public snow/ice probabilistic forecasts
• HPC input used to modify grids within GFE to produce local forecast
• Results in final collaborated forecast
HPC/WFO Collaboration via 12 planet, phone, and/or event conference calls.
WWD Collaborative Forecast ProcessWWD Collaborative Forecast Process
Collaboration DetailsCollaboration Details2010-11 season summary
224 questions from WFOs via 12Planet
22 telephone calls from WFOs
5 Conference Calls WR SR CR ER
#12 Planet
inquiries
15 21 79 108
# phone calls 0 4 2 16
#conference calls 0 1 3 1