Reading and Interpreting Weather Data - Weather for … Session 2 Reading and...Reading and...

Reading and Interpreting

Weather Data

WxLive! Session 2

Copyright © 2012 Weather4Sailors

The material contained in this document is for the exclusive use of WxLive webinar participants and may not be shared

without the permission of the copyright holder.

Objectives For the Series

• How to get weather info onboard? – How do we decide which equipment to use?

• How to read and interpret marine weather data

FYI:

• How to apply weather data to your Newport – Bermuda Race strategy will be held in June

Objectives For this Session

• How do weather systems work?

• How do we gather and interpret marine weather data

to determine future weather conditions?

• What are the best weather data sources (publically-

available)

• What are the phases of planning? – What weather data do we use in each phrase?

“Some People Are Weather-wise,

but Most Are Otherwise” Benjamin Franklin

Hosts

• Bill Biewenga – Over 400,000 nm at sea

– Multiple speed records, numerous races and deliveries

– 39 Transatlantics as well as passages through virtually every ocean of the world

– Author & lecturer

• Lou Roberts – Co-owner Weather4Sailors.com

– Winner 2008 Marion to Bermuda Short Handed Trophy

– Corporate consultant in instructional media and training

Panelists

• Ken Campbell

– Commanders’

Weather

• Joe Sienkiewicz

– National Weather

Service’s Ocean

Prediction Center

(NOAA)

Weather Acumen Questions

• Use the Chat Room to answer the

questions.

Public vs. Private

Weather Forecasters

• What’s the role of public (government)

vs. private weather forecasting?

• What’s the difference between

human/machine forecasting and

machine forecasting?

Topics

• Weather Maps (OPC)

• Satellite Images

• Radar Images

• Local Conditions

Weather Maps

Surf Anal, N Atl, Valid 06 28 07, 12Z

The Difference Ship Obs Makes

Weather Map Symbols

Weather Routing Wizard –

“Weather Map Symbols” Tool

Fronts

Professionals analyze frontal lows & high pressure centers first: Note added surface

ship observations are used to better position fronts & pressure centers…

Cold Front, Side View

Warm Front, Side View

Weather Maps

Surf Anal, N Atl, Valid 06 28 07, 12Z

Weather Maps

24 Hr Frcst, W N Atl, Valid 06 28 07, 12Z

Weather Maps

48 Hr Frcst, N Atl, Valid 06 28 07, 12Z

Weather Maps

96 Hr Frcst, N Atl, Valid 06 28 07, 12Z

Weather Maps

Surf Anal, N Atl, Valid 06 28 07, 12Z

Weather Map Animations

• Animations allow you to see the

direction and movement of weather

patterns.

Ocean Prediction Center (OPC) website

Health Break

500 mb Chart &

What It Tells Us • Numbers refer to ALTITUDE not Pressure

– All the contours are 500 mb of pressure

– Altitude is measure in meters above sea level

• Helps predict

– Speed and direction of surface lows

– Intensity of surface lows

• Influence on surface lows

– Cut off lows

– Blocking ridges

– High amplitude jet stream

– Low amplitude jet stream

500 mb Chart

• How surface low pressure system works

with the 5640 line

• Refer to 2 static maps (surface and 500

mb for the same timeframe)

500 mb Chart Valid 06 01 03, 00Z

Surface Analysis Chart Valid 06 01 03, 00Z

500 mb Chart

Cut off Low

500 mb Chart

Blocking Ridge

N Hemisphere High

N Hemisphere Low

Satellite Images Sat Pic, IR, N Atl, Valid 06 28 07, 12Z

Satellite Images Surf Anal, N Atl, Valid 06 28 07, 12Z

Scatterometer QuikScat

Scatterometer (ASCAT)

Scatterometer (OSCAT)

OSCAT in OPC operations

OSCAT

ASCAT

OSCAT and ASCAT in operations ASCAT and OSCAT: 1200 UTC 13 Mar

GFS wind speeds: 1500 UTC 13 Mar

GOES Sea Surface Temp: 1800 UTC 13 Mar

ACSAT-GFS difference: 1500 UTC 13 Mar

Numerical Forecast Models

GLOBAL ATMOSPHERIC MODELS • GFS – U.S. NWS Global Forecast System

– 4 x’s daily, global

• ECMWF – EU Center for Medium-Range Weather Forecasting

– 2x’s daily, global

• CMC – Canadian Meteorological Center

– 2x’s daily, global

• NOGAPS – Navy Operational Global Atmos Prediction System

– 4x’s daily, global

• UKMET - UK METeorological Office

– 2x’s daily, global

REGIONAL MODELS

Weather Research Forecast (WRF) Model based • NAM – U.S. North American Mesoscale Model

– 12 km to 4 km (6 hour cycle) (output hourly thru 36 hrs, then 3 hourly to 84 hrs)

• RAP – U.S. RAPid Refresh (formerly RUC, Rapid Update Cycle) – 13 km (hourly cycle) (output to 18 hrs)

• NWW3 – NOAA WAVEWATCH III

Using ASCAT/OSCAT to

confirm buoy &ship reports

Satellite Imagery Interpretation

• The Weather Routing Wizard contains

many job aids

• These job aids help simplify the

process of apply the theory in this

course.

• “How to Read Satellite Images” Tool

Animated Satellite maps

• NASA’s Global Hydrology website

shows animated and static near-real

time satellite images

NASA website

Health Break

GRIBs

• Gridded Binary files

• Based on computer models

• Common GRIB models include: • GFS – U.S. NWS Global Forecast System

• ECMWF – EU Center for Medium-Range Weather Forecasti

• CMC – Canadian Meteorological Center

• NOGAPS – Navy Operational Global Atmos Prediction System

• UKMET - UK METeorological Office

• NAM – U.S. North American Mesoscale Model

• RAP – U.S. RAPid Refresh (formerly RUC, Rapid Update Cycle)

• GFS model available at www.grib.us

Which model represents the

best forecast?

Therefore, how useful are GRIBs?

Radar

Animated Radar

• Animated radar is available on the web

• Shows rain, but not necessarily wind

• Shows clouds, but not height (vs.

satellite)

• Offshore constraints

– As a downloaded file - not practical for

offshore sailors with limited bandwidth

– Available through Sirius

• Using your radar to track fronts at night

Local Conditions

• Influences the larger, synoptic scale wx

• But CAN be the dominant weather

feature

Sea Breeze

• Weather Routing Wizard –

“Sea Breeze” Tool

Clouds & What They’re Telling Us

Weather Routing Wizard –

“Cloud Forecasting” Tool

Cloud Gallery Website –

“Cloud Gallery” website

Dealing With Islands

• Between island

– Convergent winds

– Divergent winds

• Circulation around / over islands

– Bermuda

• Night land breezes

– Topographical influences

Between Islands

Convergent and Divergent winds

Circulation around / over islands

Night land breezes

• Night land breezes are significantly influenced

by

– Topographical features

– Temp differential between land and sea

• Not a sea breeze in reverse

– Topography based:

• If cooling is taking place in adjacent mountaintops, the

cooler air at night time can roll down the mountain side

and accelerate the night breeze

– Generally weaker than sea breeze

Gulf Stream

Interaction between water and air TEMP.

• Formation of warm and cold eddies

• Resultant cloud formation.

The Planning Process

Before Departure… • The single most important decision for a successful voyage may well be prior

to your departure time.

– Know the forecast…ahead of time

– Know ahead of time what products or services you will use at sea

– Know how to work with your private weather routing service… Be

in a position to intelligently engage; they are an advisory service

only.

• The ultimate responsibility for weather forecasts and routing rests with

the skipper and his/her properly trained crew.

The Planning Process

While Underway • Monitor the weather as part of watch keeping/navigation

– Log wind speed & direction, barometric pressure, sea state

• Monitor the weather

– Near shore: VHF, Smartphone, Wifi

– Offshore: HF-SSB, Satellite

• Update the current forecast and routinely verifying it with the most

current analyses.

• Keep asking: “Is the weather evolving as planned?”

– If not…determine why and redefine routing options

Organize your Weather Files

Resources

• Contributed by all speakers

• How best to use them

– Links to recorded session

– Further Study

– Speakers’ Contact Information

– Tables, Calculators, Tools

• When they will be available

Weather Routing Wizard

Upcoming Webinars

• NorthU Trim

– Bill Gladstone, Host

– March 24 (all day)

– March 27 and 29, 7p EDT

• Performance Software Featuring

EXPEDITION

– Peter Isler, Host

– April 23 and 25, 7p EDT

• Newport – Bermuda Race Strategy

– Bill Biewenga, Host

– June 4 and 11, 7 p, 2012 EDT

For Further Study

• Articles

– Mariner’s Guide to 500 mb charts

– Mariner’s Guide to Hurricanes

– Oceanography from Space

– Arctic Impact Study

• Books and CD’s

Contacts

• Ken Campbell, Commanders’ Weather

– Tel: 1-603-882 6789

– E-mail: info@commandersweather.com

– Website: www.commandersweather.com

• Joe Sienkiewicz

– E-Mail: Joseph.Sienkiewicz@noaa.gov

• Lee Chesneau

– 206-949-4680

– lee@weatherbylee.com

– www.weatherbylee.com

• Bill Biewenga

– E-mail: billbiewenga@cox.net

– Website: www.weather4sailors.com

• Lou Roberts

– E-mail: lroberts@crsol.com

– Website: www.weather4sailors.com

Reading and Interpreting

Weather Data

WxLive! Session 2

The End

(Resources will be made available by email)