WDTB Winter Wx Workshop Oct. 8-11, 2002

WDTB Winter Wx WDTB Winter Wx WorkshopWorkshop

Oct. 8-11, 2002Oct. 8-11, 2002SummarySummary

Why Train on Winter Wx?Why Train on Winter Wx?

• Significant hazard to life and property

• 70-80 deaths / year

• $ 1 to 2 Billion / year

• Very difficult to forecast mesoscale events, pinpoint locations/timing/precip type of many large scale events due to complex nature of phenomena

Performance MeasuresPerformance Measures

• 15 hr Lead Time on Warnings

• 90% POD

• 27% FAR

• Focus on science and societal impacts to improve services

New Policy DirectivesNew Policy DirectivesNWSI 10-513NWSI 10-513

• Outlooks– >30 % chance of event in next 3-5 days

• Watches– >50 % chance of event in next 12-48 hrs

• Warnings– 80% chance of event exceeding local criteria

in next 36 hrs• Mention specific amounts

New DirectivesNew Directives

• Get out of comfort zone

• Learn from failure

• Develop local criteria that meets user needs

• Determine optimal lead times for decision makers

Winter Weather Forecast ProcessWinter Weather Forecast Process

• PDS Competency Units based on Specific Job Duties in the Winter Weather Warning Process

The PDS includes training on the tools, methodologies, time lines, and strategies used in preparing winter weather watches, advisories, and warnings

User NeedsUser Needs(PCU1)(PCU1)

• Assess customer requirements and societal impacts related to our winter weather products and services

• Optimize lead times to help decision makers – IC 1 Eastern Region Best Practices Report– See handout and user needs presentation

ClimatologyClimatology(PCU 2)(PCU 2)

• Rarity of storms (use Grumm’s web site)– http://

www.wdtb.noaa.gov/workshop/WinterWxII/Presentations/sigwxau02-new.ppt

• Recognize Arctic Outbreak Patterns– See Brad Bramer’s

presentation

Conceptual Models Conceptual Models (PCU 3 – 4)(PCU 3 – 4)

• Important to give physical basis for forecast adjustments

• Subjective and Objective forecaster techniques

Synoptic Synoptic NWP NWP Mesoscale Mesoscale

AdjustmentsAdjustments

IFPS gridsIFPS grids

NWP NWP (PCU 2-4)(PCU 2-4)

• Continues to improve with better resolution pcpn schemes

• Know changes to GFS, Eta, NMM, RUC-20, SREF output – METED web site – http://www.wdtb.noaa.gov/workshop/

WinterWxII/Presentations/WHATSNEW.PPT

HPC Guidance HPC Guidance (PCU 2 to 4 )(PCU 2 to 4 )

• Use it– Know terms

• Coordinate with HPC– http://www.wdtb.noaa.gov/workshop/

WinterWxII/Presentations/winterwx2.shw

Ensembles (PCU 2-3)Ensembles (PCU 2-3)

• Use them in objective forecast process to recognize consistencies or uncertainties in model output

• Not always right!– http://

wwwt.emc.ncep.noaa.gov/mmb/SREF/SREF.html

Synoptic AssessmentSynoptic Assessment(PCU 3)(PCU 3)

• QG forcing and Fn– http://www.wdtb.noaa.gov/workshop/WinterWxII

/Presentations/SCHULTZ_.PPT

• Ingredients method (4-panel method of diagnosis)– http://cimss.ssec.wisc.edu/goes/visit/ingredients.ht

ml

Precipitation Type ForecastingPrecipitation Type Forecasting(PCU 3-4)(PCU 3-4)

• Microphysics (top down approach)– Know strengths and limitations of various precipitation

type techniques / algorithms (eg, Ramer, Bourgouin, Baldwin, etc)

• Use BUFKIT (dendritic growth zone, pcpn type) – http://wdtb.noaa.gov/resources/projects/BUFKIT/

index.html– http://www.wdtb.noaa.gov/workshop/WinterWxII/

Presentations/ptype_wdtb_day3_aug2002.shw– Complete exercise form using BUFKIT

Precip Type Fcstg MethodologyPrecip Type Fcstg Methodologybeyond 72 hours (PCU 3)beyond 72 hours (PCU 3)

• Use pattern recognition and assess thickness values

• Use most consistent model to target potential • Top down approach

– Ice… –12C

• Identify range of possibilities

Precip Type Fcstg MethodologyPrecip Type Fcstg Methodology24 to 72 hours (PCU 3)24 to 72 hours (PCU 3)

Warm Layer Maximum Precipitation Type Precipitation TypeTemperature with ice introduced without ice introduced

< 0.5C Snow Freezing Drizzle/Rain**0.5C to 3C SN/PL Mix (0.5C) to All Sleet (3C) Freezing Drizzle/Rain**

> 3C Freezing Rain/Drizzle* Freezing Drizzle/Rain**

• Still use top down approach with higher resolution models but begin to incorporate more remotely sensed data to modify model output

Precip Type Fcstg MethodologyPrecip Type Fcstg Methodologywithin 24 hours of expected eventwithin 24 hours of expected event

(PCU 4)(PCU 4)

Mesoscale Analysis /Real-timeMesoscale Analysis /Real-time(PCU 4 – 5)(PCU 4 – 5)

• Banding potential (location of Fn)• SPC meso guidance• Use satellite trends for timing of features, forcing

mechanisms, tstms can warm sfc T• Radar orientations/ echo circles/bright band• Use Spotters• http://www.wdtb.noaa.gov/workshop/

WinterWxII/Presentations/frontogenesis_talk_020809.ppt

Topo forcing Topo forcing (PCU 4)(PCU 4)

• Know basics of mountain flow– COMET web site– http://meted.ucar.edu/mesoprim/flowtopo/

index.htm

• Improved grid spacing can help

Use of Mesoscale ModelsUse of Mesoscale Models(PCU 4)(PCU 4)

• Goal is to improve knowledge of the forecast process and use of mesoscale models

• Big Bang for Buck• Can help forecasters determine local responses

to various weather regimes – If you capture the forcing, you can capture the

response– See Bob Roz.’s LAM considerations (domain size,

time, resolution, phenom of interest)

Forecasting Blizzards/High windsForecasting Blizzards/High winds(PCU 5)(PCU 5)

• Recognize factors for development– Brad Bramer’s talk– Review representative case study (Sept. 11,

2001)

Effective CommunicationEffective Communication(PCU 6)(PCU 6)

• Timing is everything

• Make sure our products tell the whole story– Snow accum not enough– societal impacts should be coordinated prior

to the season

IFPS Smart ToolsIFPS Smart Tools

• Precipitation type algorithm

ScenarioScenarioLessons LearnedLessons Learned

• Coordination with HPC and adjacent WFOs Coordination with HPC and adjacent WFOs helped in the decision-making processhelped in the decision-making process

• SREF ensembles helped in the forecast SREF ensembles helped in the forecast processprocess

• 4-panels of “ingredients”, 2-D Fn helpful, 4-panels of “ingredients”, 2-D Fn helpful, model soundings (using BUFKIT) great for p-model soundings (using BUFKIT) great for p-type forecasting (Weta)type forecasting (Weta)

• satellite trends helpful in snowfall rates and satellite trends helpful in snowfall rates and amountsamounts

Where do you go from here?Where do you go from here?

• All presentations will be on WDTB winter weather web site (wdtb.noaa.gov )

• Make training stick by being an example

• Use the PDS on winter weather

• You’ll be hearing from us after this winter to see how techniques & training were applied

Making Training Stick Like GlueMaking Training Stick Like Glue• Plan • Research • Inform and communicate expectations • Objectively Observe• Role Model• Inspire, instill, internalize• Test techniques• Yes attitude

SummarySummary