extending geostationary satellite retrievals from observations into forecasts using goes sounder...

Extending Geostationary Satellite Retrievals from

Observations into Forecasts

Using GOES Sounder Products to Improve Regional Using GOES Sounder Products to Improve Regional Hazardous Weather ForecastsHazardous Weather Forecasts

Ralph A. Petersen : University of Wisconsin – MadisonRobert M Aune : NOAA/NESDIS/STAR - Advanced Satellite Products Branch - Madison, WI

Focus on the next 1-6 hours – Fill the Gap between Nowcasts and NWP

Update/enhance NWP guidance:- Be Fast and updated very frequently

Use ALL available data - quickly:- “Draw closely” to good data- Avoid analysis smoothing / superobing

(Issues of longer-range NWP) Anticipate rapidly developing weather events:

- “Perishable” guidance products need rapid delivery

- Detect the “pre-storm environment”- Increase lead time Probability ofDetection (POD)- Reduce False Alarm Rate (FAR)

Run locally if needed:- Few resources needed

- Improve Forecaster’s Situational Awareness

What is an Objective NearCasting System

0 1 5 6 hours

Fill the GapBetween Nowcasting & NWP

A NearCasting model should:

13 April 2006 – 2100 UTC900-700 hPa GOES PW

0 Hour Ob Locations

Updated Hourly - Full-resolution 10 km data - 10 minute time steps

Objectives:♦Preserve Data Maxima/Minima/Large Gradients♦Use Geostationary satellite data at Full Resolution♦Be Fast

Methodology:

The Lagrangian approach first interpolates wind data to locations of full resolution GOES multi-layer moisture & temperature observations

How the Lagrangian NearCasts work:


0 Hour Ob Locations

13 April 2006 – 2100 UTC900-700 hPa GOES PW3 Hour NearCast Image



Methodology:


Next, these high-definition data are moved to future locations, using dynamically changing winds with ‘long’ (10 min.) time steps.

.



0 Hour Ob Locations

13 April 2006 – 2100 UTC900-700 hPa GOES PW3 Hour NearCast Image


Vertical Moisture Gradient (indicating Convective Instability)(900-700 hPa GOES PW -700-500 hPa GOES PW)

3 Hour NearCast : Valid 0000UTC


Methodology:


Next, these high-definition data are moved to future locations, using dynamically changing winds with ‘long’ (10 min.) time steps.

. Finally, the moved ‘obs’ values from each layer are then both:

1) Transferred back to an ‘image’ for display of ‘predicted DPIs’,

2) Several parameters are combined to produce derived parameters and 3) Results between layers are compared to obtain various “Stability Indices” that are combined with ‘conventional tools’ to identify mesoscale areas where severe convective will develop - even after convective clouds appear.

Verification


Recent Progress

• Example many new cases where NearCasts of GOES vertical moisture gradients (a necessary condition for Convective Instability) helped isolate areas of Hazardous Weather Potential– Useful in many seasons/regions of US

• Severe Convection• Emphasis on rapid development of isolated storm

– Heavy Precipitation– Output in GRIB-II and NWS Graphics formats– . . .

• Expanded analyses of Convective Environment

• Diagnose case using SEVIRI data

Mid-layer Moisture(900-700 hPa GOES PW )

7 Analyses plus 6-Hour NearCast from 1100UTC10 February, 2009

Formationof

Strong Pre-Frontal

Convection

Moving GOES data from Observations to Forecasts

Event: Winter Tornado

Begin Date: 10 Feb 2009, 14:52:00 PM CST

Begin Location: Edmond, Oklahoma

Path: 6.5 miles

End Date: 10 Feb 2009, 15:05:00 PM CST

End Location: Not Known

Magnitude: EF2

Vertical Moisture Gradient(900-700 hPa GOES PW - 700-500 hPa GOES PW)

7 Analyses Plus 6-Hour NearCast from 1100UTC10 February 2009

Moving GOES data from Observations to Forecasts

Formationof

Strong Pre-Frontal

ConvectionVerification: Radar/ReportsPsuedo-Convective Stability

Using true Equivalent Potential Temperature ( Theta-E or Θe ) instead of TPW, to diagnose Total Thermal Energy and

Convective Instability

Fundament Question:

Do GOES temperature profiles add information regarding the potential for the timing and location of convection development

to that already present in the DPI moisture products already being used?

A case when Severe Thunderstorm Warnings were issued for all of western Iowa

Rapid Development of Convection over NE IA between 2000 and 2100 UTC 9 July 2009

Using Equivalent Potential Temperature ( Theta-E or Θe ) instead of TPW to diagnose Total Thermal Energy and true Convective Instability

A case when Severe Thunderstorm Warnings were issued for all of western Iowa

Theta-E measures TOTAL moist energy,not only latent heat potential

Lower-Layer Θe NearCasts shows warm / moist air band moving into far NW Iowa, where deep convection formed rapidly by 2100 UTC.

Vertical Θe Differences shows full Convective Instability - at the correct time and place

- GOES temperature data in Θe do enhance the vertical moisture gradient fields used previously.

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Rapid Development of Convection over NE IA between 2000 and 2100 UTC 9 July 2009

6 hr NearCast for 2100 UTCLow to Mid Layer Theta-E Differences

6 hr NearCast for 2100 UTCLow Layer Theta-E

How well can the NearCasting approach be applied to SEVIRI

data?• Tests were conducted with 2 time periods of retrievals obtained 8

and 6 hours prior to development of the F2/T4 tornado that occurred in Częstochowa, Poland near 16UTC - 20 July 2007.

– Full description in Pajek, Iwanski, König and Struzik from last meeting– Results using 09UTC retrievals (provided by König) shown here

• NearCast results valid from 09UTC to 15UTC• Initial Wind and Geopotential data from NCEP GFS @ 0.5o resolution• Results displayed on 0.25o output grid

• NearCasts were made or a wider variety of variable than in previous US tests

– Multi-Layer and Total Precipitable Water– Lower- and Mid-tropospheric parameters:

• Temperature• Mixing Ratio• Temperature at LCL• Equivalent Potential Temperature

• Several Stability Indices were derived from NearCasts of these primary variables

• Tests were conducted with 2 time periods of retrievals obtained 8 and 6 hours prior to development of the F2/T4 tornado that occurred in Częstochowa, Poland near 16UTC - 20 July 2007.

– Full description in Pajek, Iwanski, König and Struzik from last meeting– Results using only 09UTC retrievals (provided by Konig) shown here

• NearCast results valid from 09UTC to 15UTC• Initial Wind and Geopotential data from NCEP GFS @ 0.5o resolution• Results displayed on 0.25o output grid

• NearCasts were made for more variable than in previous US tests– Multi-Layer and Total Precipitable Water– Lower- and Mid-tropospheric parameters:

• Temperature• Mixing Ratio• Temperature at LCL• Equivalent Potential Temperature

• Several Stability Indices were derived from NearCasts of these primary variables

• Note: Apologies for “quality” of graphics - but they get the point across– Currently integrating NearCasts into McIdas-V

How well can the NearCasting approach be applied to SEVIRI

data?

900-700 hPa Precipitable Water – 09Z – F00:Valid 09Z

Slide Orientation

NearCast Length and

Valid Time indicated by F00:Valid 09Z

Display area:

Centered on Poland11o to 27o E

and 47o to 60o N

Location ofF2/T4

Tornado indicated by Cross

900-700 hPa Precipitable Water – 09Z – F06:Valid 15Z Middle-Layer Precipitable Water

Observations show:

- No terrain effects

------------------------------ Maximum of Middle-Layer PW

- Only one observedmaximum in area

-Initially West of tornado location

- Moves to region North-West of Tornado at time of development

Lower-Tropospheric Temperature

Observations show:

- Temperature front North of area of tornado formation

- Highest Temperatures were well south of tornado

-----------------------------

Temperature – 840 hPa – 09Z – F00:Valid 09Z

Temperature – 840 hPa – 09Z – F06:Valid 15ZLower-Tropospheric Temperature

Observations show:

- Temperature front North of area of tornado formation

- Highest Temperatures were well south of tornado

-----------------------------

- Front strengthens and temperatures increase near and west of tornadic area during NearCast

- Low-level Lifting ?

Equivalent Potential Temperature (Өe) – 840 hPa – 09Z – F00:Valid 09ZLower-Tropospheric Equivalent Potential Temperature (Өe)

Observations show:

- Significant front immediately North of area where tornado formed (a potential lifting mechanism)

- Area of Warm/Moist air South-West of tornado development

Equivalent Potential Temperature (Өe) – 840 hPa – 09Z – F06:Valid 15ZLower-Tropospheric Equivalent Potential Temperature (Өe)

Observations show:

- Significant front immediately North of area where tornado formed (a potential lifting mechanism)

- Area of Warm/Moist air South-West of tornado development

-Warm/Moist air moved to area where severe convection was forming rapidly by 15UTC

Convective Instability

Observations show:

- Weakest Stability South-West of tornado development----------------------------

- NearCasts show combined effects of differential advection between Warm/Moist air at low levels and Dry/Cool air aloft

- Area of greatest Convective Instability moves to tornado site at same time as rapid lapse rate change

Vertical Equiv. Pot. Temp. Difference (∂Өe/∂p) – 840-480 hPa – 09Z – F00:Valid 09ZConvective Instability

Vertical Equiv. Pot. Temp. Difference (∂Өe/∂p) – 840-480 hPa – 09Z – F00:Valid 09ZConvective Instability Convective

Instability

Observations show:





Instability

Observations show:





Instability

Observations show:



- Area of weakest strengthens as it move to tornado site at same time as rapid lapse rate change


Instability

Observations show:




Lifted Index

Difference between TLCL840

and T480

Observations show:

- Weakest Stability South-West of tornado development- …but…

- NearCasts show:

- Initial Instability weakens and moves East

- Second area of Instability forms to west and moves to tornado site by 15Z

Lifted Index – 840-480 hPa – 09Z – F00:Valid 09Z


Lifted Index


and T480

Observations show:


- NearCasts show:



Lifted Index


and T480

Observations show:


- NearCasts show:




Lifted Index


and T480

Observations show:


- NearCasts show:



Summary• Additional tests show utility of GOES DPI NearCasts in detecting the pre-convective environment for hazardous weather in many US cases

• Effect for detecting isolated convection and reducing warning area sizes• Important for predicting various type of Hazardous Convection• Useful in adding detail to Heavy Precipitation Forecasts

• GOES Temperature Soundings provide additional information beyond TPW in defining Convective Potential when using Өe

•Tests using SEVIRI retrieval positive

• Useful in diagnosing the pre-convective environment evolution

• Applicable to many forecasting Indices

FUTURE• Beta-test version available for distribution by mid-October

• Major US testing at SPC/NSSL in 2010

• Plans for improved graphics using McIDAS-V Ensembles , Consistency, . . .

extending geostationary satellite retrievals from observations into forecasts using goes sounder...

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wind data

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lagrangian nearcasts

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