# Presentation: 034849

## Developing Methods to Nowcast Convective Initiation and Total Lightning Using Satellite Infrared Convective Cloud Information

- Simon J. Paech1, John R. Mecikalski1, Kristopher M. Bedka2
*1**Atmospheric Science Department*
*University of Alabama in Huntsville*
*2**Cooperative Institute for Meteorological Satellite Studies*
*University of Wisconsin-Madison*
**Supported by:**
** ****NASA ASAP Initiative**
**NASA New Investigator Program (2002)**

## How this began...

-  Which cumulus will become a thunderstorm?
-  GEO satellite seems to be well-suited to address this question.
- able to monitor cumulus over time
- excellent coverage (both spatial and temporal) of regions prone to 	convective storms (60° S – 60° N)
* **Tracking cumulus*, while monitoring their growth, should allow for some predictive skill of thunderstorm development.
- Limited to > 1 km cumulus in clear-sky conditions (GOES visible).

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## Motivation

-  especially true over oceanic regions
-  Mid-flight convective storm initiation and growth represents a significant hazard for aviation interests
-  Lightning: ground and air hazard
- The NASA sponsored **A**dvanced **S**atellite **A**viation weather **P**roduct (**ASAP**) initiative was started to better infuse satellite data into the FAA Aviation Weather Research Program’s diagnostics and forecasts

***Motivation***

## Objectives

*** ******Convective Initiation: first detection of significant precipitation echoes (> 35 dBZ) from cumulus clouds by ground-based radar***
*** ******Lightning initiation: first thunderstorm lightning (usually in-cloud)***
- To develop an automated CI/LI nowcasting (0-1 hour forecasting) algorithm using these pre-CI/LI signatures
-  To assess the skill of CI/LI nowcasts through the coincident use of GOES satellite and WSR-88D data

***Objectives***

## The CI Nowcast Algorithm: 4 May 2003

_**2000 UTC**_

***The CI Nowcast Algorithm: 4 May 2003***

-  Satellite-based CI indicators provided *30-45 min advanced notice* of CI in E. and N. Cent. KS

***CI Nowcast Pixels***

-  Algorithm currently running real-time over various U.S. regions and Central America

## How it works...

## GOES-12 imagery

***GOES-12 imagery***

*GOES-12 visible (1 km) and infrared imagery (4-8 km) - 15 min resolution*

## Convective Cloud Mask

-  To determine where cumulus are present and only look at those pixels (greatly reduces CPU requirements)
-  (Mask Identifies 5 types of convectively-induced clouds)

- low cumulus, mid-level cumulus, deep cumulus, thick cirrus ice cloud/cumulonimbus tops, thin cirrus anvil ice cloud

## CIMSS “Mesoscale” Atmospheric Motion Vectors

***CIMSS “Mesoscale” Atmospheric Motion Vectors***

- “Operational Settings”

- New Mesoscale AMVs
- (only 20% shown)

-  To track cumulus features back in time for IR satellite trends, and predict future cumulus location (pixel basis).

## WSR-88D reflectivity data

-  WSR-88D reflectivity used to determine if CI (> 35 dBZ) has occurred at a pixel

## Predict whether CI will occur

** ****Evaluate Pre-CI Satellite Signatures **
-  Numerous & varied convective events studied
-  Compared GOES IR TB, and channel-differencing (and their time trends) with co-located WSR-88D imagery to identify difference thresholds for cumulus in a pre-CI state  8 infrared “Interest Fields”
-  Cumulus cloud pixels that meet 7 of 8 interest field criteria are flagged as 	likely to evolve into a mature cumulonimbus within the following 1 hour

_**2000 UTC**_

## Satellite-Lightning Relationships

***Satellite-Lightning Relationships***

-  *Current Work:* Develop relationships between IR trends and total lightning toward nowcasting future lightning occurrence
-  Using N.AL LMA 5 min flash rates in 1km bins within 150 km range of network center.  Co-located with sat & rad.

**2047 UTC**

**2147 UTC**

**2040-2050 UTC**

**2140-2150 UTC**

## Where things are going...

-  Working on validation of the CI algorithm to quantify POD, FAR
-  Regression analysis to build quantitative CI Interest Field statistical relationships (relative contributions)
-  Paper will be submitted in near future
-  Doing the same with LI & flash rate nowcasting

## Contact Information/Publications

***Contact Info:***
- Simon Paech: simon@nsstc.uah.edu
- John Mecikalski: johnm@nsstc.uah.edu
***UAH CI Studies web page:***
- http://nsstc.uah.edu/johnm/ci_studies.html
***Publications:***
- Mecikalski, J. R. and K. M. Bedka, 2005: Forecasting convective initiation by monitoring the evolution of moving cumulus in daytime GOES imagery. **In Press.** *Mon. Wea. Rev.* (IHOP Special Issue, ~August 2005).
- Bedka, K. M. and J. R. Mecikalski, 2005: Applications of satellite-derived atmospheric motion vectors for estimating mesoscale flows. **In Press**. *J. Appl. Meteor*.