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

15

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

16

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?

Dan.Petersen@noaa.gov

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