WORLD METEOROLOGICAL ORGANIZATION
COMMISSION FOR BASIC SYSTEMS
OPAG on DPFS
MEETING OF THE CBS (DPFS) EXPERT TEAM ON
OPERATIONAL WEATHER AND FORECASTING
PROCESS AND SUPPORT
GENEVA, SWITZERLAND
22-24 OCTOBER 2014
DPFS/ET-OWFPS/Doc. 4.6
(15.X.2014)
_______
Agenda item : 4.6
ENGLISH ONLY
Use and interpretation of Very Short-Range Forecasting (VSRF) products
(Submitted by Jianjie Wang and Alice Sores)
Summary and purpose of document
This document provides background information on the issue of
use and interpretation of existing VSRF products.
Action Proposed
The meeting is invited to review the current status of use and interpretation of existing VSRF
products, and to discuss the future plan for the issue of development of guidelines on how to use
and interpret satellite products for VSRF at the regional level using the SWFDP–Eastern Africa as
a pilot.
Annex: Content of the “Best Practice Document” (EUMETSAT Convection WG)
Reference:
(1) CBS-15/Doc. 4.4(1).
(2) Final report of CBS ICT-DPFS Extraordinary Meeting on 21-25 Jan 2013.
(3) Draft minutes of WWRP WGNR meeting on 14-15 Aug 2014.
(4) Presentations from CMA-JMA-KMA Joint Workshop on Mesoscale NWP
on 28-30 Aug 2014.
(5) Existing products using in VSRF operation in CMA, Sep 2014.
1.
Background information
1.1 A request relevant to the VSRFissue, from the approved document of CBS-15/Doc. 4.4(1) :
4.4.2.16
While noting that many NMHSs in developing countries do not have
operating weather radars and/or national-wide radar coverage to support timely and
accurately forecasts and warnings of severe convective in the very short-range forecasting
period, the Commission agreed that satellite data processing systems and products
represent powerful tools for very short- to short-range forecasting. In addition, recognizing
that there are difficulties in the uptake of these products into weather forecasting daily
routines of the forecasters, the Commission requested the OPAG on DPFS, in collaboration
with the WMO Space Programme and the WWRP/CAS Working Group on Nowcasting
Research (WGNR), to develop guidelines on how to use and interpret these products at the
regional level, taking into account regional and national requirements, using the SWFDP–
Eastern Africa as a pilot. In the same context, the Commission was informed that
EUMETSAT plans to make a number of products (e.g. precipitation, soil moisture, cloud,
etc.) from the Satellite Application Facility (SAF) on Support to Operational Hydrology and
Water Management (H-SAF) and SAF Nowcasting and Very Sort-range Forecasting
available via EumetCast, which could be of relevance to NMHSs in developing countries in
RA I.
1.2 A part relevant to the response on the above VSRF issue by the DPFS, from the Final report
of CBS ICT-DPFS Extraordinary Meeting:
4.2 Under this agenda item, and taking into account the outcomes of the CBS-15, the ICT
developed Top Level Objectives (TLOs) for the OPAG on DPFS and its three Expert Teams
(ETs), aligned with the CBS directions, as follows:
(a) Operational Weather Forecasting Process and Support
• Develop guidance to assist Members with improved access to high-resolution regional
NWP
• Coordinate upper-air verification
• Develop standard procedures for surface verification
• Update observation monitoring procedures
• Use of NWP for hazard risk management
• Develop guidelines on how to use and interpret existing very short-range forecasting
(VSRF) products
• Coordinate operational aspects of sand and dust storm
2. Incomplete information on the current status of use and interpretation of existing VSRF
products
2.1 Increased satellite products on nowcasting applications for convection monitoring,
tracking, and warnings are available in EUMETSAT, NOAA NESDIS of USA, SSEC (Space
Science and Engineering Center) of Wisconsin University, and some other meteorological
services (for instance, in Europe and Eastern Asia). Especially, in EUMETSAT, the satellite
based nowcasting applications range from describing the pre-convective atmosphere to the
early detection of growing Cumulus clouds and to fully developed convective storms. A
document, called “Best Practice Document” (BPD) and described satellite based nowcasting
products and methods, exists. The document is a “living” document, changing as new
applications and insights are developed. The content of the” Best Practice Document” is
shown in the annex, and detailed information about BPD could be found in the website
http://www.essl.org/cwg.
2.2 For the 0-2h range in the VSRF, ground based OBS (the radar, lightning detection,
AWS and wind profiler etc) products are used in many WMO member countries, in addition
to satellite products. And similarly as that in satellite products, there are gaps in effective
use and proper interpretation of ground based OBS products, especially the radar based
products, in operational nowcasting application.
2.3 For the 2-6h range in the VSRF, products are mainly from high-resolution limited-area
meso-scale models. More products related to clouds, precipitation types, convection
instability and PBL conditions are derived in addition to conventional model variables and
derived variables commonly used in short- medium range forecasts. Relatively to the 0-2h
range, the use and interpretation of meso-scale model products to the 2-6h/12h range in the
VSRF have benefited by the longer history on using model products in short-range forecasts.
3.
Future plan
3.1 Further investigation on the status of operational use of existing VSRF products by a
survey to WMO member countries through CBS secretariat, as the background information
and material for the development of guideline on use and interpretation of VSRF products,
and for other relevant issue of CBS DPFS.
3.2 To form an ad hoc joint task team (CAS/CBS), to develop guidelines on how to use and
interpret satellite products for VSRF at the regional level, using the SWFDP–Eastern Africa
as a pilot.
3.3 Based on the experiences gained from the pilot activity, to step further on the
development of general guideline on use and interpretation of satellite and maybe other type
OBS based VSRF products.
ANNEX:
Content of the “Best Practice Document” (EUMETSAT Convection WG)
Best Practice Document
Purpose
A document describing the ―best practices in the diagnosing and monitoring of convective storms
using satellite remote sensing, with an emphasis on the use of geostationary satellites, specifically
Meteosat Second Generation
For EUMETSAT Convection Working Group
Editors
John Mecikalski
Kristopher Bedka
Marianne König
Version 2.0 of 01 July 2012
Contents
1 Introduction ........................................................................................................................................ 5
2 Pre-Convective Environment: Where Will Storms Form, how Do We Optimally Use Satellite and
NWP? ........................................................................................................... ………………………….7
2.1 Introduction .................................................................................................................................... 7
2.2 The MSG Global Instability Index (GII) Product .......................................................................... 7
2.3 The SEVIRI Physical Retrieval (SPhR) Product of the NWC-SAF ............................................. 10
2.4 Combined Instability Index (CII) Work Performed at SAWS ...................................................... 13
2.5 Forward (Temporally) Advection of Layer Averaged Fields: NearCasts ..................................... 16
2.6 Boundary Layer Moisture Inferences ............................................................................................ 20
2.7 High Resolution Atmospheric Motion Vectors: NWC SAF High Resolution Winds product
(HRW) ................................................................................................................................................. 22
2.8 Mesoscale Atmospheric Motion Vectors for Moisture Convergence ........................................... 24
3 Convective Initiation Nowcasting: Which Clouds Will Become Thunderstorms in the Near
Future? .............................................................................................................................................. 34
3.1 Convective Cloud Identification ................................................................................................... 34
3.2 GOES CI Interest Fields ............................................................................................................... 36
3.3 MSG Interest Fields, as Related to Physical Processes in Growing Cumulus
Clouds .................................................................................................................................................. 42
3.4 Evolution of Retrieved Cloud Properties for Growing Cumulus Clouds ..................................... 45
3.5 First-Flash Lightning Initiation Indicators and Interest Fields ..................................................... 47
4 Mature Storm Characteristics: How long will a storm last and how hazardous is it? …………….. 54
4.1 Storm Intensity Indicators: Coupled IR and Lightning Diagnostics ............................................ 54
4.2 Storm Movement, Intensification/Decay, and Lifetime Estimation ............................................ 56
4.2.1 The NWC-SAF Rapidly Developing Thunderstorm (RDT) Product ....................................... 57
4.2.2 The DLR CumulonimBus Tracking and Monitoring (CbTram) Product ................................. 58
4.3 Overshooting Tops ....................................................................................................................... 59
4.4 Cold-U/V and Cold-Ring Signatures ........................................................................................... 70
4.5 Objective Cold U-V Signature Detection .................................................................................... 74
4.6 Convective Cloud Top Height ..................................................................................................... 75
4.7 Cloud Top Microphysics and Inferred Processes in Mature Storms ........................................... 76
4.8 Aviation Turbulence Indicators and Cloud-Induced Turbulence ................................................. 81
4.9 Satellite Rainfall Estimation ......................................................................................................... 81
4.9.1 Convective Rainfall Rate (CRR) Product of the NWC-SAF ..................................................... 82
4.9.2 Precipitation Products Provided by the H-SAF ......................................................................... 84
5 End-to-End Convection Nowcasting Techniques ............................................................................. 86
5.1 The COALITION approach: an EUMETSAT Fellowship research project at
MeteoSwiss ......................................................................................................................................... 86
6 References ........................................................................................................................................ 93