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The Similar Soundings The Similar Soundings Technique For Technique For Incorporating Pattern Incorporating Pattern Recognition Into The Recognition Into The Forecast Process at WFO Forecast Process at WFO BGM BGM Mike Evans Mike Evans Ron Murphy Ron Murphy

The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

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Page 1: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

The Similar Soundings Technique The Similar Soundings Technique For Incorporating Pattern For Incorporating Pattern

Recognition Into The Forecast Recognition Into The Forecast Process at WFO BGMProcess at WFO BGM

Mike EvansMike EvansRon MurphyRon Murphy

Page 2: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

OutlineOutline

Forecasting issues with lake effect snowForecasting issues with lake effect snow What is the “similar soundings” technique?What is the “similar soundings” technique? Application of the technique for lake effect Application of the technique for lake effect

snow.snow. Other Applications / The future.Other Applications / The future.

Page 3: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Lake effect snow forecastingLake effect snow forecasting

Currently, we have two ways to use models Currently, we have two ways to use models to forecast lake effect snow.to forecast lake effect snow.

Examine data from “low-resolution” models. Examine data from “low-resolution” models. Use pattern recognition.Use pattern recognition.

Examine explicit forecasts from high Examine explicit forecasts from high resolution models.resolution models.

Page 4: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Example: Forecasts from the Eta Example: Forecasts from the Eta ModelModel

Large single band Associated Eta12 3 hr QPF

Smaller multi-bands Associated Eta 12 3 hr QPF

Page 5: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

SummarySummary Explicit forecasts from the Eta can be used to imply location of larger bands. (Not so Explicit forecasts from the Eta can be used to imply location of larger bands. (Not so

good with intensity).good with intensity). Forecasts from the Eta can still be used to forecast smaller bands – forecast larger-Forecasts from the Eta can still be used to forecast smaller bands – forecast larger-

scale pattern, then use pattern recognition / rules of thumb.scale pattern, then use pattern recognition / rules of thumb.

Page 6: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Example: Explicit forecasts from high Example: Explicit forecasts from high resolution modelsresolution models

5 km MM5 Model – 24 hr precipitation 2.5 km MM5 Model – 950 mb omega

Intense single band east of Lake Ontario

Smaller scale Finger Lakes bands

Page 7: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Some arguments for using low-resolution Some arguments for using low-resolution models and pattern recognitionmodels and pattern recognition

We have years of experience and “rules of thumb” We have years of experience and “rules of thumb” associated with forecasting lake effect snow this way.associated with forecasting lake effect snow this way.

High-detail, high resolution forecasts may look realistic, but High-detail, high resolution forecasts may look realistic, but can be completely wrong.can be completely wrong.

Small-scale, multi-band lake effect is difficult to model – Small-scale, multi-band lake effect is difficult to model – even at high resolutions - output looks noisy.even at high resolutions - output looks noisy.

Problems continue with getting full-resolution Eta data into Problems continue with getting full-resolution Eta data into AWIPS.AWIPS.

Pattern recognition can be used with low resolution Pattern recognition can be used with low resolution ensemble forecasts (SREFs).ensemble forecasts (SREFs).

Page 8: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

The best method may be a The best method may be a combination of the old and new combination of the old and new

waysways

Always start with observations!Always start with observations! Examine output from lower resolution models.Examine output from lower resolution models. Use pattern recognition to make a “first guess” Use pattern recognition to make a “first guess”

on location and intensity of bands.on location and intensity of bands. Examine output of high resolution, explicit Examine output of high resolution, explicit

forecasts of lake effect snow. forecasts of lake effect snow. Combine information from both sources to make Combine information from both sources to make

a forecast.a forecast.

Page 9: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

The Similar Sounding Technique The Similar Sounding Technique Aids Forecasters With Pattern Aids Forecasters With Pattern

Recognition (step one). Recognition (step one).

Page 10: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Current ApplicationsCurrent Applications

This technique was originally designed to This technique was originally designed to help forecast lake effect snow.help forecast lake effect snow.

The technique was also examined for The technique was also examined for severe weather forecasting this past severe weather forecasting this past summer.summer.

Page 11: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

The ConceptThe Concept

Pattern Recognition is a critical skill for forecastersPattern Recognition is a critical skill for forecasters The best forecasters have a wealth of experience and can The best forecasters have a wealth of experience and can

recognize patterns associated with significant weather recognize patterns associated with significant weather events.events.

Example: Lake Effect snow occurs with favorable Example: Lake Effect snow occurs with favorable combinations of temperature, moisture, stability and wind combinations of temperature, moisture, stability and wind direction.direction.

This technique is designed to assist forecasters with This technique is designed to assist forecasters with recalling details from previous events, in order to recognize recalling details from previous events, in order to recognize the potential for future significant weather events.the potential for future significant weather events.

Page 12: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Why do this?Why do this?

““I can’t remember what happened I can’t remember what happened yesterday, let alone 2 years ago”yesterday, let alone 2 years ago”

Page 13: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

The “Similar Soundings” Technique The “Similar Soundings” Technique For Lake Effect SnowFor Lake Effect Snow

A 2 year database of lake effect snow events and A 2 year database of lake effect snow events and parameters has been developed (includes “null cases”).parameters has been developed (includes “null cases”).

An application has been developed that ingests current An application has been developed that ingests current forecast data from BUFKIT soundings, and compares forecast data from BUFKIT soundings, and compares several parameters to the data in the historical data base.several parameters to the data in the historical data base.

Forecasters can modify the data before comparisons are Forecasters can modify the data before comparisons are made.made.

An algorithm is run that determines the 3 most similar An algorithm is run that determines the 3 most similar historical soundings.historical soundings.

Forecasters can examine the soundings and the observed Forecasters can examine the soundings and the observed weather that occurred with these 3 most similar days. weather that occurred with these 3 most similar days.

Page 14: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

How are the 3 most similar sounding How are the 3 most similar sounding days determined?days determined?

Each historical sounding is compared to Each historical sounding is compared to current forecast data, and assigned points current forecast data, and assigned points based on similarity.based on similarity.

Parameters that are compared for similarity Parameters that are compared for similarity are related to: Wind direction and speed, are related to: Wind direction and speed, stability, moisture and microphysics. Time of stability, moisture and microphysics. Time of year and time of day is also considered.year and time of day is also considered.

Points are added, 3 highest totals are Points are added, 3 highest totals are returned to the user as “most similar”.returned to the user as “most similar”.

Page 15: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Where does the data come from?Where does the data come from?

Eta 6 hour forecasts, displayed on BUFKIT.Eta 6 hour forecasts, displayed on BUFKIT. 12 hour forecasts were used when 6 hour 12 hour forecasts were used when 6 hour

forecasts were not available. forecasts were not available. Data taken at SYR, ITH and BGM.Data taken at SYR, ITH and BGM. Note: With the exception of the largest, Note: With the exception of the largest,

strongest bands, the 12 km Eta is not really strongest bands, the 12 km Eta is not really explicitly forecasting individual lake effect explicitly forecasting individual lake effect snow bands.snow bands.

Page 16: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

So, the similar soundings application So, the similar soundings application should…should…

Help forecasters remember what happened Help forecasters remember what happened two years ago.two years ago.

Helps forecasters use pattern recognition Helps forecasters use pattern recognition based on data from a model which is not based on data from a model which is not explicitly forecasting (most) snow bands, but explicitly forecasting (most) snow bands, but is forecasting the larger-scale environment.is forecasting the larger-scale environment.

Page 17: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Example of using the technique to Example of using the technique to anticipate lake effect snowanticipate lake effect snow

Page 18: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

LES Example… continuedLES Example… continued

Page 19: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

LES example… continuedLES example… continued

Page 20: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

A Range of Possibilities?A Range of Possibilities?

Page 21: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

A Range of Possibilities?A Range of Possibilities?

Page 22: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Other Applications / The FutureOther Applications / The Future

Severe Weather ApplicationsSevere Weather Applications Enhanced web pagesEnhanced web pages Searchable databaseSearchable database

Page 23: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Can this technique also be used for Can this technique also be used for anticipating severe weather anticipating severe weather

structures?structures? A 3 year database of severe weather events and A 3 year database of severe weather events and

associated parameters has been developed.associated parameters has been developed. Forecasters enter data into an online checklist. Forecasters enter data into an online checklist. Parameters entered into the checklist are compared to Parameters entered into the checklist are compared to

data from the data base.data from the data base. An algorithm is run that compares current data to An algorithm is run that compares current data to

historical data. The 3 most “similar” historical dates are historical data. The 3 most “similar” historical dates are returned. returned.

Forecasters can examine the soundings associated with Forecasters can examine the soundings associated with the 3 similar events, and are given a summary of what the 3 similar events, and are given a summary of what occurred on those days.occurred on those days.

Page 24: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Keep in mind…Keep in mind…

For severe weather, this technique is not For severe weather, this technique is not really designed to determine whether or not really designed to determine whether or not severe weather will occur.severe weather will occur.

It’s better at determining, if severe weather It’s better at determining, if severe weather occurs, what form will it take (null events are occurs, what form will it take (null events are not included in the historical data base).not included in the historical data base).

Page 25: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

ExampleExample

Page 26: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Example… continuedExample… continued

Page 27: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Example… continuedExample… continued

Page 28: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

A Range of Possibilities?A Range of Possibilities?

Page 29: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

A Range of Possibilities?A Range of Possibilities?

Page 30: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

So, how did the algorithm work this So, how did the algorithm work this summer?summer?

The technique shows promise in The technique shows promise in differentiating between organized severe differentiating between organized severe weather structures and pulse storms.weather structures and pulse storms.

Sometimes, a larger range of outcomes is Sometimes, a larger range of outcomes is indicated than what the forecaster may have indicated than what the forecaster may have been anticipating.been anticipating.

Should work better as more events are Should work better as more events are added to the database (about 50 so far). added to the database (about 50 so far).

Page 31: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

The future…The future…

Web pages will be enhanced with radar loops and weather Web pages will be enhanced with radar loops and weather maps.maps.

Eta model will be replaced by either the RUC or WRF next Eta model will be replaced by either the RUC or WRF next year.year.

Eventually, the severe and LES databases will be used for Eventually, the severe and LES databases will be used for searches. searches.

For example: show me all of the cases where the CAPE For example: show me all of the cases where the CAPE was greater than 3000 J/kg. Show me all of the tornado was greater than 3000 J/kg. Show me all of the tornado cases. Show me all of the cases where the inversion cases. Show me all of the cases where the inversion height was below 800 mb, the mean wind was from 300height was below 800 mb, the mean wind was from 300°° and the dendritic snow growth zone was greater than 100 and the dendritic snow growth zone was greater than 100 mb deep, etc. mb deep, etc.

Page 32: The Similar Soundings Technique For Incorporating Pattern Recognition Into The Forecast Process at WFO BGM Mike Evans Ron Murphy

Questions??Questions??