Objective Short-Term Alert based Objective Short-Term Alert based on signatures of severe weather on signatures of severe weather

using radar.using radar.

R. Valenti, M. Guichandut, G.Pujol, X. CalleR. Valenti, M. Guichandut, G.Pujol, X. Calle..

National Weather ServiceNational Weather Service

National Weather CenterNational Weather Center

ARGENTINAARGENTINA

Presentation IndexPresentation Index

• Short review about Radar System at the NWS Short review about Radar System at the NWS (Argentina) (Argentina)

• Alert System and Short Term Advices (STAs) Alert System and Short Term Advices (STAs) description, their scales and issuing criteria.description, their scales and issuing criteria.

• Study Objectives.Study Objectives.• Comparative study: Alerts vs STAsComparative study: Alerts vs STAs• Correlation with Confirmed EventsCorrelation with Confirmed Events• Pattern EventsPattern Events• ConclusionsConclusions• AcknowledgmentsAcknowledgments

Presentation IndexPresentation Index

Short review about Radar System at the NWS Short review about Radar System at the NWS (Argentina) (Argentina)

• Alert System and Short Term Advices (STAs) Alert System and Short Term Advices (STAs) description, their scales and issuing criteria.description, their scales and issuing criteria.

• Study Objectives.Study Objectives.• Comparative study: Alerts vs STAsComparative study: Alerts vs STAs• Correlation with Confirmed EventsCorrelation with Confirmed Events• Pattern EventsPattern Events• ConclusionsConclusions• AcknowledgmentsAcknowledgments

Short review about Radar System and Short review about Radar System and implementation of Short Term Advices (STAs) at implementation of Short Term Advices (STAs) at

the SMNthe SMN

Year 2000.Year 2000. Setup of DWSR 2500 Doppler Radar C Band at Ezeiza, Setup of DWSR 2500 Doppler Radar C Band at Ezeiza, Buenos Aires province.Buenos Aires province.

Year 2003, October.Year 2003, October.a) Replacing of control terminal and setup of JS Meteoview a) Replacing of control terminal and setup of JS Meteoview

software (in arrangement with Czech Hydrological and software (in arrangement with Czech Hydrological and Meteorological Institute –CHMI-). Meteorological Institute –CHMI-).

b)Collecting of “Leading Cases”.b)Collecting of “Leading Cases”.

Year 2003, November 17th.Year 2003, November 17th. Definitive criteria establishment for Definitive criteria establishment for STAs issuing. STAs issuing.

Year 2005, march. Year 2005, march. Beginning of this study.Beginning of this study.

Presentation IndexPresentation Index

Short review about Radar System at the NWS Short review about Radar System at the NWS (Argentina) (Argentina)

Alert System and Short Term Advices (STAs) Alert System and Short Term Advices (STAs) description, their scales and issuing criteria.description, their scales and issuing criteria.

• Study Objectives.Study Objectives.• Comparative study: Alerts vs STAsComparative study: Alerts vs STAs• Correlation with Confirmed EventsCorrelation with Confirmed Events• Pattern EventsPattern Events• ConclusionsConclusions• AcknowledgmentsAcknowledgments

Total Area Definition for STAs issuing.Total Area Definition for STAs issuing.

The total area defined for STAs issuing is defined by the hole The total area defined for STAs issuing is defined by the hole ArgentinArgentiniian territory within an Operative Range 240 km far from an territory within an Operative Range 240 km far from Ezeiza city (where Radar Site is placed), extended up to 350 km in Ezeiza city (where Radar Site is placed), extended up to 350 km in extraordinary cases.extraordinary cases.

The STAs are made in order to alert mesoscale phenomena: The STAs are made in order to alert mesoscale phenomena: intense storms, hail and gusts.intense storms, hail and gusts.

The radar system schedule used consists in an hybrid 16 elevation The radar system schedule used consists in an hybrid 16 elevation volume volume scan scan every 12 minutesevery 12 minutes. (3 elev. 480 km range, 10 elev. 240 . (3 elev. 480 km range, 10 elev. 240 km range, 3 elev. 120 km range)km range, 3 elev. 120 km range)

The STAs issuing is made by a remote sensing specialized The STAs issuing is made by a remote sensing specialized forecaster and standardized by an operational procedure.forecaster and standardized by an operational procedure.

Total Area Defined for STAs issuing.Total Area Defined for STAs issuing.

ExtendedExtended RaRangenge

(350 km)(350 km)

Operative Operative RaRangenge

((240240 km) km)RadarRadarSiteSite

An STA typical coverage areaAn STA typical coverage area

The area is defined The area is defined by segments by segments set set

between moreover between moreover 200 GIS integrated 200 GIS integrated

pointspoints

Established criteria for STA issuingEstablished criteria for STA issuing

Radar image must show at least one of this characteristics:Radar image must show at least one of this characteristics:

A) Cell with suspended 50 dBz reflectivity (or more) over 5 km A) Cell with suspended 50 dBz reflectivity (or more) over 5 km height. (Most used criteria)height. (Most used criteria)

B) Cell with suspended 44 dBz reflectivity (or more) over 7,5 km height, B) Cell with suspended 44 dBz reflectivity (or more) over 7,5 km height, over a continuous area larger than an area that would be filled by an over a continuous area larger than an area that would be filled by an isolated cell.isolated cell.

The STA will be obligatory issued every time the area would not The STA will be obligatory issued every time the area would not be under a previous Alert advice, or whenever the severity be under a previous Alert advice, or whenever the severity forecasted would be higher than the forecasted by a previous forecasted would be higher than the forecasted by a previous Alert. Alert.

The STA The STA will expire will expire automatically automatically after three hours.after three hours.

Alert System total responsibility areaAlert System total responsibility area(in green)(in green)

Alert Areas taken for this studyAlert Areas taken for this study(delimited in purple)(delimited in purple)

AREA I

AREA II

AREA III

AREA IV

Established criteria for an Intense Storm Alert Established criteria for an Intense Storm Alert issuingissuing

Synoptic scale forecast of intense storms, gusts and hail in a lapse Synoptic scale forecast of intense storms, gusts and hail in a lapse of 24 hs or less.of 24 hs or less.

Updated every 6 hours if necessary.Updated every 6 hours if necessary.

Presentation IndexPresentation Index

Short review about Radar System at the NWS Short review about Radar System at the NWS (Argentina) (Argentina)

Alert System and Short Term Advices (STAs) Alert System and Short Term Advices (STAs) description, their scales and issuing criteria.description, their scales and issuing criteria.

Study Objectives.Study Objectives.• Comparative study: Alerts vs STAsComparative study: Alerts vs STAs• Correlation with Confirmed EventsCorrelation with Confirmed Events• Pattern EventsPattern Events• ConclusionsConclusions• AcknowledgmentsAcknowledgments

Objectives of this studyObjectives of this study

A.A. Verify by comparing the Alerts issued by the Alert System vs. Verify by comparing the Alerts issued by the Alert System vs. the Short Term Advices (STAs) the capability of the STAs based the Short Term Advices (STAs) the capability of the STAs based on the use of the radar system for:on the use of the radar system for:

Make warnings of severe phenomena in not covered areas by Make warnings of severe phenomena in not covered areas by previous or any other Alert advices.previous or any other Alert advices.

Work as triggers of larger scale Alert advices.Work as triggers of larger scale Alert advices.

Objectives of this studyObjectives of this study

B.B. VerifyVerify the efficiency of the existing criteria the efficiency of the existing criteria for issuing STAs for issuing STAs combined with the Alert System for warning severe weather combined with the Alert System for warning severe weather comparing them with Confirmed Severe Weather Events (CEs).comparing them with Confirmed Severe Weather Events (CEs).

C.C. Extract from CEsExtract from CEs other characteristics that could complement other characteristics that could complement the criteria.the criteria.

Presentation IndexPresentation Index

Short review about Radar System at the NWS Short review about Radar System at the NWS (Argentina) (Argentina)

Alert System and Short Term Advices (STAs) Alert System and Short Term Advices (STAs) description, their scales and issuing criteria.description, their scales and issuing criteria.

Study Objectives.Study Objectives. Comparative study: Alerts vs STAsComparative study: Alerts vs STAs• Correlation with Confirmed EventsCorrelation with Confirmed Events• Pattern EventsPattern Events• ConclusionsConclusions• AcknowledgmentsAcknowledgments

Comparative study between the Alert System and Comparative study between the Alert System and the Short Term Advices (STAs)the Short Term Advices (STAs)

WARNING:WARNING: It should be taken in account that due different time and It should be taken in account that due different time and space scales are involved, it will not be measured the compared space scales are involved, it will not be measured the compared effectivity between the Alert System and the STAs. What is more, it effectivity between the Alert System and the STAs. What is more, it will be tried to show will be tried to show their enhancement and complementation.their enhancement and complementation.

For integratFor integratinging them from the user point of view, they were joined in the them from the user point of view, they were joined in the “Advertisement System”“Advertisement System”

Users of the Alert System and STAsUsers of the Alert System and STAs(Advertisement System)(Advertisement System)

ALERTSALERTS

STAsSTAs •Civil Defence InstitutionsCivil Defence Institutions

•Security ForcesSecurity Forces

•Airport Meteorological OfficesAirport Meteorological Offices

•Media Media (Only Alerts, by this moment)(Only Alerts, by this moment)

Advertisement System

Alerts and STAs Responsibility Area comparisonAlerts and STAs Responsibility Area comparison

AREA I

AREA II

AREA III

AREA IV

Areas Areas AlertasAlertasAreas Areas

AlertasAlertasAreas Areas AlertasAlertasAlertAlert

AreaArea

STA Operative STA Operative RangeRange

STAs STAs Extended Extended

RangeRange

Alerts and STAs issued from november 03’ up to Alerts and STAs issued from november 03’ up to december 04´ in the study regiondecember 04´ in the study region

01020304050

NOVDIC

ENEFEB

MAR

ABRM

AYJU

NJU

LAGO

SEPOCT

NOVDIC

MonthSTAs (126)

ALERTS (50)

The seasonal distribution of the STAs matches significantly with the The seasonal distribution of the STAs matches significantly with the Alerts, showing Alerts, showing an absolute maximum during the southern an absolute maximum during the southern hemisphere summer.hemisphere summer.

02468

1012141618

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Local Hour

Abs

olut

e F

req.

Hourly frequence of STAs issuingHourly frequence of STAs issuing

The maximum STAs issuing frequence is near 20 hs. (loc), some time after the maximum heating take place The maximum STAs issuing frequence is near 20 hs. (loc), some time after the maximum heating take place in summer.in summer.

It can be seen another relative maximum near 5 hs. (loc).It can be seen another relative maximum near 5 hs. (loc).

STAs classification for its comparison with AlertsSTAs classification for its comparison with Alerts

The STAs were separated by:The STAs were separated by:

STAs issued with no coincidence with any previously issued Alert STAs issued with no coincidence with any previously issued Alert advice: advice: “STAs without Alert”“STAs without Alert”

STAs issued followed by one inmediate Alert for the same area: STAs issued followed by one inmediate Alert for the same area: “triggering STAs”“triggering STAs”

STAs issued although an Alert was already issued for the same STAs issued although an Alert was already issued for the same area. area. “STAs with Alert”. “STAs with Alert”. (This STAs issuing is obligatory every (This STAs issuing is obligatory every time there are detected conditions with higher severity than the time there are detected conditions with higher severity than the announced by previous the Alert).announced by previous the Alert).

Compared issued Alerts vs STAs Compared issued Alerts vs STAs from Nov 03’ to Dic 04from Nov 03’ to Dic 04

Results interesting the amount of “triggering STAs” and the “STAs without Results interesting the amount of “triggering STAs” and the “STAs without Alert”, what implies a Alert”, what implies a net earning in advertisements due to severe net earning in advertisements due to severe weather in the area.weather in the area.

80 STAs w ithout Alert

63%

39 STAs w ith Alert31%

7 "triggering" STAs6%

Advertisements Increase of the Advertisement Advertisements Increase of the Advertisement System due to the complement of the Alert System System due to the complement of the Alert System

and the STAsand the STAs

43

43

130

7 80

0 20 40 60 80 100 120 140

Alert System & STAs

Alert System only

Adv. by Alert System only Adv. by "Triggered" Alerts

Adv. By STAs w ithout Alert

Increase of 200%

Presentation IndexPresentation Index

Short review about Radar System at the NWS Short review about Radar System at the NWS (Argentina) (Argentina)

Alert System and Short Term Advices (STAs) Alert System and Short Term Advices (STAs) description, their scales and issuing criteria.description, their scales and issuing criteria.

Study Objectives.Study Objectives. Comparative study: Alerts vs STAsComparative study: Alerts vs STAs Correlation with Confirmed EventsCorrelation with Confirmed Events• Pattern EventsPattern Events• ConclusionsConclusions• AcknowledgmentsAcknowledgments

Correlation with Confirmed Events (CEs)Correlation with Confirmed Events (CEs)

The Confirmed Events (CEs) are composed by:The Confirmed Events (CEs) are composed by:

A) the official data requests made to the NWS Meteorological Information A) the official data requests made to the NWS Meteorological Information Center Center due to damages caused by severe weatherdue to damages caused by severe weather

B) B) The direct eye seen eventsThe direct eye seen events informed by users and professional weather informed by users and professional weather watchers.watchers.

Important:Important:

This composition of the data base results on a very limited one, because not This composition of the data base results on a very limited one, because not always that a severe weather event takes place, inform requests are always that a severe weather event takes place, inform requests are generated, or is somebody seeing it. This usage is forced due to be the generated, or is somebody seeing it. This usage is forced due to be the unique data source available. Field severe weather data is not active unique data source available. Field severe weather data is not active collected. collected.

Confirmed Events (CEs) of severe storms matching with Confirmed Events (CEs) of severe storms matching with STAs and AlertsSTAs and Alerts

7 CEs w ith STA & w ith

Alert51 %

1 CE w ithout STA & w ithout

Alert7%

3 CEs w ith Alert21%

3 CEs w ith STA21%

Confirmed Events matching STAsConfirmed Events matching STAs

4 CEs w ithout STA29%

10 CEs w ith STA71%

Due to the issuing criteria for STAs, the absence of STAs in CEs previously Due to the issuing criteria for STAs, the absence of STAs in CEs previously covered with Alerts (3 of the 4 CEs showed in the graphic) does not mean an covered with Alerts (3 of the 4 CEs showed in the graphic) does not mean an effectivity failure, but it has been taken in this way in order to get conservative effectivity failure, but it has been taken in this way in order to get conservative results.results.

Confirmed Events matching the Alert System and STAs Confirmed Events matching the Alert System and STAs (Advertisement System)(Advertisement System)

1 CE w ithout STA and

w ithout Alert7%

13 CEs w ith STA and/or

Alert93%

Presentation IndexPresentation Index

Short review about Radar System at the NWS Short review about Radar System at the NWS (Argentina) (Argentina)

Alert System and Short Term Advices (STAs) Alert System and Short Term Advices (STAs) description, their scales and issuing criteria.description, their scales and issuing criteria.

Study Objectives.Study Objectives. Comparative study: Alerts vs STAsComparative study: Alerts vs STAs Correlation with Confirmed EventsCorrelation with Confirmed Events Pattern EventsPattern Events• ConclusionsConclusions• AcknowledgmentsAcknowledgments

Pattern EventsPattern Events

The Pattern events are those situations which were used for establish The Pattern events are those situations which were used for establish and confirm the criteria used for STAs issuing. Here are and confirm the criteria used for STAs issuing. Here are presented the most significative.presented the most significative.

The Pattern Events are composed by:The Pattern Events are composed by:

Events with confirmed severe weather previous to the study Events with confirmed severe weather previous to the study period: period: “Leading Events”.“Leading Events”.

Events with confirmed severe weather under Alert and/or STA: Events with confirmed severe weather under Alert and/or STA: “Proof”.“Proof”.

Events with confirmed severe weather neither under Alert nor Events with confirmed severe weather neither under Alert nor STA: STA: “Counter proof”.“Counter proof”.

Leading Event.Tornado in

Chivilcoy city

Leading Event.Severe storms in

Carlos Casares city

Leading Event.Very intense gusts

Proof.Tornado

(with Alert and STA)

Proof.Tornado

near Azul AD (with STA)

Counter-proof. Tornado near Dolores city

(Without Alert and without STA)

Absence of strong

reflectivity

Common characteristics of severe weather registered with the Radar System in this study

At least, one of this characteristics is present:At least, one of this characteristics is present:

Cell with Cell with 50 dBz reflectivity50 dBz reflectivity or higher suspended over 5km height. or higher suspended over 5km height.

TiltingTilting of the cell in the movement direction of the cell in the movement direction

Isolated cells or line organization. Isolated cells or line organization.

Tops round 10 km height (non significant in an infrared satellite Tops round 10 km height (non significant in an infrared satellite image)image)

Presence of low reflectivity clouds with Presence of low reflectivity clouds with horizontal horizontal curved curved developmentdevelopment

Clear air inclusions Clear air inclusions near the reflectivity maximum.near the reflectivity maximum.

Presentation IndexPresentation Index

Short review about Radar System at the NWS Short review about Radar System at the NWS (Argentina) (Argentina)

Alert System and Short Term Advices (STAs) Alert System and Short Term Advices (STAs) description, their scales and issuing criteria.description, their scales and issuing criteria.

Study Objectives.Study Objectives. Comparative study: Alerts vs STAsComparative study: Alerts vs STAs Correlation with Confirmed EventsCorrelation with Confirmed Events Pattern EventsPattern Events ConclusionsConclusions• AcknowledgmentsAcknowledgments

ConclusionsConclusions

The implementation of the STAs using the radar system allowed to The implementation of the STAs using the radar system allowed to increase increase in 200% the total of severe weather advertisementsin 200% the total of severe weather advertisements within the STAs within the STAs Issuing Area previously covered only by Alerts.Issuing Area previously covered only by Alerts.

The Alert issuing The Alert issuing got increased in 16%got increased in 16% withing the STAs issuing area, due withing the STAs issuing area, due to the triggering STAs influence.to the triggering STAs influence.

Although –as it was mentioned- the Confirmed Severe Weather Events Although –as it was mentioned- the Confirmed Severe Weather Events Data Base results very limited Data Base results very limited the rate of Confirmed Events matching the the rate of Confirmed Events matching the STAs -71%- and the rate of Confirmed Events matching the Alert STAs -71%- and the rate of Confirmed Events matching the Alert System and STAs (Advertisement System) about 93 %System and STAs (Advertisement System) about 93 % is auspicious. is auspicious.

ConclusionsConclusions

The criteria initially defined for STAs issuing seem to be enough The criteria initially defined for STAs issuing seem to be enough simple and sensitivesimple and sensitive for detecting severe weather. for detecting severe weather.

There are common characteristics between the studied cases that There are common characteristics between the studied cases that should be taken in account at the moment of an STA issuing, as should be taken in account at the moment of an STA issuing, as well as well as seasonal backgroundseasonal background (an STAs “season” could be defined (an STAs “season” could be defined from September to April) from September to April) and hourly preferenceand hourly preference (20 hs and 05 hs). (20 hs and 05 hs).

The The practical focuspractical focus of this study results in a very good feedback for of this study results in a very good feedback for the STA forecasters, proposing a new step in this activity in the the STA forecasters, proposing a new step in this activity in the NWS of Argentina, proposing future investigations, joining new NWS of Argentina, proposing future investigations, joining new events to the data base and the project of an active data field events to the data base and the project of an active data field collection.collection.

Presentation IndexPresentation Index

Short review about Radar System at the NWS Short review about Radar System at the NWS (Argentina) (Argentina)

Alert System and Short Term Advices (STAs) Alert System and Short Term Advices (STAs) description, their scales and issuing criteria.description, their scales and issuing criteria.

Study Objectives.Study Objectives. Comparative study: Alerts vs STAsComparative study: Alerts vs STAs Correlation with Confirmed EventsCorrelation with Confirmed Events Pattern EventsPattern Events ConclusionsConclusions AcknowledgmentsAcknowledgments

AcknowledgmentsAcknowledgments

Dr. Petr Novak (Czech Hidrological and Meteorological Institute)Dr. Petr Novak (Czech Hidrological and Meteorological Institute)

Argentinian NWS Meteorological Information Center (CIM)Argentinian NWS Meteorological Information Center (CIM)

Dolores weather watching stationDolores weather watching station

Azul weather watching stationAzul weather watching station

Thank YOU !Thank YOU !

www.meteofa.mil.arwww.meteofa.mil.ar