Effective Use of Satellite Information in Severe Wx Fcasting:Use of blended data products:

J.N. Kagenyi Senior Meteorologist RS/GIS

IMTR-NAIROBISWFDP NOV.2012

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Data available

Synoptic (MDD) Satellite (MSG Channels, RGB products) MPEF, SAF

Products e.g. (Now casting SAF), MODIS products, jason etc

NWP models different spatial and temporal resolutions (UK Models

(3,to 0.5 deg), WAFs,ECMWF models, Local models (LAM, regional models) and many more

Diagnostic models (manual plots and analyses, development and forecast)

Radar data for nowcasting, Climatology (seasonal information to help with

shift from normal)

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Synergie System designed to: Integration of all data

Integrate all data in a workstation Equipping the weather person with

power of information Role for experienced Forecaster is to

obtain optimum information from ALL the available data to make Reliable Forecast

Capacity to handle all this data is the subject of your presence Here!

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Possible Steps in Severe WX Identification Using Synergie system

Assumptions all participants have access of Synergie system

back home. Availability of Near Real Time (NRT) data for this

exercise. Step 1. What season are we? Rainy season!

Hence certainty of S/WX case is more certain Step 2. display a VIS Image if daytime

otherwise ch4 (3.9) or RGB Convection(10-9,9-4,9-0) at night time, to identify location of any convection by water clouds

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Step 2: Display VIS (day)

Several convective cells at different stages of development

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Step3: Use WV5 and WV6

Use WV 6.2 and 7.3 microns to identify potential areas with enough moisture to support further development (Deep column)

White areas are moist and cold, dark or grey areas are low in WV and warmer.

Upper level moisture from WV5 (6.2) Medium Level moisture from WV6

(7.3)

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Display WV5 data for Moisture

1. Convective cells are within the high density water vapour.

2. They exist in convergence zone.region

3. Moisture supply is high

4. Time is 12:12 pm

5. Further development possible likely

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Display WV-6 for Mid Level Moisture

Sufficient moisture at mid levels

Question Is there enough Thermodynamic (Pressure Field) convergence at lower levels and Upper air diffluence (wind data or Animations) to generate deep convection?

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Step 4: Animate to Identify trend on convective areas

You may animate Vis or IR, RGB consecutive images for the last 15,30,45,60 minutes

This will answer the two questions: Is convection increasing or decaying? What direction are systems leading? How fast is the system developing?

Channel 3(1.6): good for daytime as reflectance reduces for developing severe storms and brighteness for decaying storms

At night use night time microphysics RGB (10-9,9-4,9-0) or 5-6,9-4,5i air-mass)

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Animation on Dev. convection Animate=2003 observation. It is evidence on this animation that

between 8-12:30 the region around southern lake Victorian

and land east of the lake developed from shallow convection, white reflectance on ch3 to deep convection of large ice crystals (low reflectance=grey) similarly over Kisumu and Western Nyanza of Kenya.

use Ch9 to confirms temp changes.

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Step 5: Confirm microphysics or stages of convection by RGB149,

Deep red indicates very cold large ice clouds.

The Yellow brown are areas with small ice and water clouds at stage of development see over lake Tanganyika.

• Cyan is cloud free and warm

• Deep Blue is warm water body

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Step 5:Confirm microphysics or stages of convection by RGB139

Deep dirty brown indicates very cold large ice clouds.

The yellow areas are clouds with small ice and water clouds at stage of development- Super-cooled (-33 deg) clouds, see over lake Tanganyika.

• Cyan is cloud free and warm

• Deep Blue is warm water body.

• Thin Cirrus clouds appear dark brown

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Step 6: Get synoptic data 3-6 hours

View reported synoptic data for synoptic hours.

Confirm from dry bulb and web bulb data for drying or increase in moisture from depression values or differences of ( Ta-Td)

You may use conditional plotting of Synergy tools. Area whose( Ta-Td) <=1 Moist or cloudy Areas whose Ta-Td =>8 dry air

conditions

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Full Synoptic chart at 15:00 utc

Scarce data stations requires to be complemented with Satellite data

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Overlay Display: Airmass rgb , Synoptic chart Surface obs on-22/11/11

1. Current Wind analysis suggests a convergence zone as shown

2. Position of deep convection is supported by convergence of the winds

3. Moist Easterly winds supply moisture

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2/2 Synoptic chart: with Overlay AirmassSA -22/11/11

1. Dry cold air-mass from Southern Tip of Africa.

2. This appears to be under St Hellena high pressure ridge cell (descending air). supports synoptic p/gradient

3. Moisture: dry bulb 30oC wet bulb -4oC. (Dry air)

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Step 7. Severe weather arises from deep convection

Deep convection goes beyond medium and upper tropopause hence

Any weather feature that causes WV5-WV6 >0 generates TS and Heavy Showers/ rain

Solar radiation & Mechanical lifting (wind field convergence zone or orographic lifting) contribute to development of severe weather.

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Step 7: analysis WV5-WV6 product

Dark is negative

White is positive or almost equal to zero

Analysis for Deep convection

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Step8: WV5 Merge with AIRMASS RGB

Synergie Under tool important for And comparison

WV5 under Airmass RGB

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Areas of deep convection RGb139

Areas of deep convection in Red

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Step 9: AIRMASS RGB (5-6,8-9,0-5)

To detect dry

and

moist air sources

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Step 10: WV5 and areas of Jetstreams

Positions of Jetstreams affectsWeather in their region of influence for instance creation of strong outflows at the tropopause level .

The Onset of a season could be associated with the intensity andthe position of JetstreamsE g. EAST Africa Low Level jet (July –September)

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Step 11: ECMF2.5 ITCZ and Areas of confluence on 850 hPa wind :ea

1. Satellite imagery confirms the identification of convergence zone by a belt of Cloud clusters.

2. Image analysis gives colours that depict the type of system and the stage of development

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Step12: NWP wind at 850 Hpa 22.11.11

Areas of low level convergence

Corresponds with areas of deep clouds

Causing High MPE values

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Data: Merging three layers

Streamlines on

200 hPa BLUE

850 hPa (RED) and IR 10.8 on background .24 hrs shift.

Notice the position of Outflow on 200

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Compare RGB and NWP Wind

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NWP AND SW FCASTING

NWP data and the Synoptic data report.1. Gives great harmony on data analysis to forecasters. and In particular when NWP replicates the weather as observed on Satellite The Belt of convergence on

NWP wind analysis on 850 hPa identifies areas of expected Severe Weather.

Meridional Arm of ITCZ is denoted red

The Identification of pressure features provides tools of decision making in Wx fcasting.

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22/11/11 MPE Rain estimate

Will your forecast give betterResults than this estimate

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MPE Overlay on day microphysics RGB

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WV6 mid level moisture: 22/11/11

Active ITCZ zone is clearly defined on this mid level signal map. DRC and neighboring countries, Botswana Zambia, are wet. Seasonally the Sothern African countries Except Namibia and SA are experiencing the Onset of rains.

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Upper Air data for Nowcasting

Ascent analysis: 1. Very Unstable at lower

levels.2. Generally moist

atmosphere but dry at 450 hpa

3. Easterly Wind pattern conducive for afternoon WX activities

Fcast: Showers and T/S over several places over Nairobi and Highlands East .

Lake basin: Heavy TS/Showers over most places.

Flooding Alert! In Lake region

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Presentation of Wx Fcast for your Area

Exercise: Create a forecast for Severe WX for your regions: 5 slides

Present to us.Use SynergieForm groups of 4Use 20 Minutes:

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Goodbye

Kwaheri na ASANTE