Marine Weather Forecasting Resources
Marine Weather Forecasting Resources Forecast Data Lots of great information, however often poorly qualified Forecast limitations often misunderstood Information overload
Talk Objectives Explain how forecasts are made Understand limitations Encourage your own exploration of weather information
1995 - Cruised - Maine to Caribbean No weather issues except 4 day gale mid passage 1996 - Return to Maine
1995 Atlantic Hurricane Tracks 19 named storms (> 34 kts), 21 tropical cyclones (> 64 kts) Activity throughout Hurricane Season – June 1 - November 30 165 years of storms & hurricanes NOAA
NOAA Minimize risk … Transit south as hurricanes reduce & winter storms begin Atlantic Basin (North Atlantic, Caribbean & Gulf of Mexico) Number of storms per 100 years
Jan, Feb, Mar, April Very low risk 1998 began Maine to New Zealand Cruise 2.5 years October 1998 Hurricane Mitch Track Started in Caribbean basin, went thru Central America, north of Bermuda, died near Scotland
Departed Maine for Bermuda 7 days before Mitch formed
Storm passed north of us anchored in Bermuda winds 60 kts + Hurricane Mitch Category 5 Max winds 180 mph / 249 km/h Second deadliest Atlantic Hurricane on record 11,000 fatalities in Central America
Panama Canal Winter 1998, cruised West Indies November 1999, waited in Aruba for passage to Panama Canal
1999 Hurricane Lenny Track “Wrong Way Lenny” W to E track, formed in Western Caribbean
Aruba
Panama Canal Nov 17, 1999 Hurricane Lenny over the Virgin Islands Category 4 Peak winds 155 mph / 249 km/h
Dominican Republic
Windward Island Chain Aruba
Venezuela Weather Tools @ the Time
• Internet prior to departure NOAA / NWS forecasts 10 day cover
• HF / SSB radio & modem Weather faxes & texts from GMDSS forecast & warning providers (Global Marine Distress & Safety System) 3 day / 72 hour cover
Weather net – Herb on South Bound II 10 day cover
• Inmarsat C GMDSS satellite system with text weather bulletins for boat location & e mail communication
• Commercial weather router – major passages only e mail communication on Inmarsat C 10 – 14 day cover Forecasting - Physical Process Simulation
heavy reliance on Air flow on spinning globe with Coriolis deflection effect mathematical modelling Differential heating Jet Streams very hot to frigid cold air masses different pressures
Australia Water vapor condensing & evaporating releasing & absorbing heat
NZ Variable cloud cover reflecting & trapping radiation
Aerosols reflecting & trapping radiation (burning, volcanoes, dust)
Antarctic Differential flow over rough vs. smooth surfaces
Each physical principle is translated into an equation & written in computer code
Set of partial equations with no exact solution
Not close to 100% accurate
Impossible without modern computers Models totally reliant on “initialization” data
Land Weather Stations Balloon data Ship observations Ocean weather buoy data
Automated Balloon Launcher Airplane reports
More data = greater accuracy Populated land areas better than open ocean NZ Met Service 84 land observation stations 5 weather balloon sites Incl. Raoul Isl. & Chatham Isls. Balloon Atmospheric Profile Measurements wind, temp, dew point, humidity
Tephigram Available on METVUW
Red - temperature
Blue- dew point temp. Moored Meteorological Ocean Buoys July 2018 National Data Buoy Center NOAA Floating Weather Buoys July 2018 National Data Buoy Center - WMO Ship Weather Reports July 18 – 20, 2018 NOAA / WMO “Global Telecommunications System” World Meteorological Organization
World wide net work collection & communication of weather data
Collected 4 X / day @ 6 hr increments
3 main centers (Melbourne, Washington DC, Moscow) & 15 regional hubs
Real time access by forecast agencies for modeling etc.
Models divide Earth’s surface into “grid – cells”
4 km to 40 km squares Up to 60 km high Each cell has a certain resolution “Spatial Resolution” = Precision Distance from one calculation / data point to another
One data point = 1 wind speed value, 1 temp value etc. Low Resolution High Resolution 4 calculation points 100 calculation points Low Resolution Grid vs. High Resolution Each box = 1 degree x 1 degree / 60 nm X 60 nm / 111 km x 111 km
NOAA GFS 0.25 degree data NOAA NMM model 0.1 degree data 1 data point every 28 km 1 data point every 11 km 4 data points total 100 data points total Any data presented between points has been interpolated Meteoblue Temperature modeling
Low Resolution 40 km between points
High Resolution 4 km between points Resolution of Selected Models
GFS / NOAA Global Forecast System = 13 km NOAA issues it @ 28 km
ABM, Access A model (covers NZ) 12 km
“European model” (ECMWF) 9 km
Meteoblue, N. Z. NEMS model 8 km
Meteoblue, Central Europe 4 km
ABM, Access C model 1.5 km
Predict Wind, statistical post - processing 1 km Match the Model to the Application
28 km Res - open ocean & flat terrain
8 – 10 km – terrain with moderate complexity
1 – 4 km Res – complex alpine terrain
1 km needed to see valley detail
Generally, increasing Res X 2 = 10 X computing power
Certain situations very difficult to predict
• Thunder Storms exact location (areas can be forecast)
• Alpine terrain (only very high res models cover complexity)
• Frontal Low & High Pressure Changes (air parcels rupture rapidly - great complexity)
When complexity increases - reliability decreases
Shift to risk management mode
• Change your plans • Get ready for worst scenario • Keep a more detailed watch on the forecasts Forecasts should be viewed relative to predictability Meteoblue 14 day forecast
Predictability %
Temp. high & low means plus range
Range of possible Forecast for precipitation “Onawe” May 8 – 22, 2018 NZMS “Severe Weather Outlook”
Predictibility
Low Confidence 20% chance (1 of 5) of event happening
Moderate Confidence 40% chance (2 of 5)
High 60% chance (3 of 5)
Eight Forecast Sources
N Z Met Service Australian Bureau of Meteorology METVUW Earth / Nullschool Windy.com ECMWF / European Model Predictwind Meteoblue Internet Forecasts Quick Access Often use several services Pin to start page or task bar at any one time New Zealand Met Service NZ data not provided by other sites
• Isobar charts with “features”
• Rain radar
• GMDSS information marine forecasts & warnings
Highly regarded - UK Met Service Model
240 staff 20 PhD meteorologists & oceanographers (Including Met Ocean Solutions Ltd.) MSLP with Features Many other forecast sources don’t ID features New Zealand Met Service
April 10, 2018 Autumn early winter blast Rain Radar Copyright NZMS
Also available on METVUW but NZMS better resolution
April 10, 2018 “Marine Forecast Areas”
Coastal GMDSS definition: Up to 10 -20 nm offshore “Ocean Area Forecasts & Warnings” GMDSS Global Marine Distress & Safety System
Part of SOLAS (Safety of Life at Sea) Agreement covers > 8 meter LOA vessels 170 countries
The prime source for forecast & warnings
Very broad brush but expert human input, not just model data
Minimum 2 X / day, broadcasts Voice, Text, Maps VHF, HF radio, Inmarsat satellite, Navtex GMDSS “Metareas” (21) Official voice, text & fax broadcasts for VHF, SSB & satellite
Link to map on NZMS web site NZ MetService HF/SSB Radiofax Maps
Tasman Sea MSLP Current / H+30 / +48/ +72 Only go out 3 days SW Pacific MSLP larger area covered
WX Features do not appear on 48 & 72 hour products
48 hr prognosis MSLP analysis - current Taupo Maritime Radio Fax Maps Fax maps - no wind speed / direction data
You must calculate based on isobar spacing then apply a set of rules *
Basic steps for calculating in:
Mariners Met Pack by Bob McDavitt
Modern Marine Weather by David Burch
* The same isobar spacing has different wind speeds with different latitudes. Wind slows with increasing latitude due to Coriolis turning effect. Voice not Fax Text reports broadcast to Inmarsat C receivers NZMS Southwest Pacific Low Bandwidth Satellite Modem Maps Bookmark page to directly access without browsing NZMS 3 day Rain Forecast July 26, 2018 NZMS 5 day rain forecast July 26, 2018 9 AM
Source: UK Met Office “New Zealand” Visible Satellite Image July 25, 2018 1 PM
Visible, no Infra red
1 of 3 Sat Images: “New Zealand” = Visible “Tasman Sea” = Infra Red “Australia IR”
Midnight Visible Sat Image
Images are for 24 hours in 1 hour increments “Tasman Sea” 24 hours in 1 hour increments Infrared Satellite IR sees in the dark July 25, 2018 Images all night 10 AM IR = temperature Only IR, no visible The whiter the cloud, the colder & higher “Australia Infra Red” July 26, 2018 3 PM Australian Bureau of Meteorology
“Interactive” = animated 7 day forecast Lots of Variables & Locations MSLP & Precipitation
ABM “ACCESS – R” model = 12 km resolution Surface Temperature 500 hPa Winds – Bottom of Jet Stream “Winds Aloft” or “Steering Winds” Different views like “Globe View” “Southern Hemisphere” View ABM MSLP Past 6 days Significant Wx approaching NZ MSLP Prognosis - Next 4 days to come ABM - good one stop shop for sat images
Shows features possibly missed by models
Infra red “Zehr” Enhanced “False Color” Infra red ABM Link to Japan Meteorological Agency High - definition Satellite Images JMA Himawarei - 8 April 11, 2018 New Zealand Met Service Infrared JMA image April 10, 2018 Victoria University at Wellington (VUW) Understand model limitations Based on NOAA’s Global Forecast System model Free, basic world wide model More accurate - Meteoblue & ECMWF
Pink = 1 mm / 6 hr GFS Global Forecast System NOAA
Grid 34 Southern Hemisphere
Entire Earth covered 2 domains: N. & S. Hemispheres Resolution 28 km - first 7 days 70 km - day 8 to 16 GFS
30 year old model - improved over time Significant update due late 2019
Currently based on air flow = wave patterns
Fronts & depressions far more complex: sharp edges & vertical movement
Assumes forces act the same at all atmospheric levels They don’t Not as precise as other models for Complex terrain Front development Storm, cyclone development Cloud development Precipitation
Does not provide adequate analysis for predicting tropical systems, frontal activity or convergence zones Good model for …
Large scale circulation patterns: winds & temps
Flat terrain & oceans
Predicting Jet Streams /steering winds GFS is free to public
Used by lots of sites & free GRIB file sources
Use GFS along with official text & voice forecasts &
Maps with surface features CF’s , WF’s, troughs etc. = human input European Centre for Medium – range Weather Forecasts “The European Model”
Estab. 1975 / 350 staff Supported by 34 states & commercial accounts
Produce “ensemble forecasts”
The world’s most accurate model
Computationally very heavy Europe's most powerful supercomputer World wide Products
Includes New Zealand Ensemble Forecasting
One ensemble / one forecast = 52 model runs, simultaneously 1 = control - unmodified model 51 = with slightly different possible initial conditions & model variables
Red – 51 individual model runs Light blue – control Blue – final output mean Free Access - shows only isobar & probability maps
Expensive forecasts to access directly
Predict Wind & Windy.com have ECMWF forecasts
MSLP & MSLP & Normalized standard deviation Standard Deviation Meteoblue 14 Day “Ensemble”
7 model comparison
Day 1 – 4 good agreement & certainty
Day 5 -10 increasing uncertainty
Model agreement is correlated with certainty
Average of several models often more accurate than most individual models UK Met Office 9 member ensemble modelling Used by NZMS Probability map for 24 hour precipitation > 10 mm in 24 hrs Earth /Nullschool
Animated maps of global weather
2013 created by Cameron Beccario, offered for free
Made weather vector graphics prominent Vectors = paths, not pixels
Weather - GFS model
Other models for ocean currents & temp anomalies, atmos. chemistry Lots of parameters
Place circle to display parameter data Surface Wind April 10, 2018 1800 hrs
Frigid air drawn up from Antarctic Surface Air Temp April 10, 2018 Plus 15°C
Minus 10°C
Minus 40°C Wind 500 hPa (Jet Stream / Steering Wind height) Sea Surface Temperature Anomaly (temp anomaly from daily average 1981 – 2011) April 10, 2018 noon NZDST
Black = normal Red-Orange = above average Blue = below average Sulphur dioxide Earth / Nullschool
Excellent visual tool
Awkward for multiple day forecasts
GFS model not for high res. weather
Limitations addressed by 2014 launch of Windy.com Animated vector map program with data tables Windy.com Free, no ads Uses GFS plus 2 more precise models
Nullschool code completely rewritten by Ivo Lukacovic, Czech Republic
Hobby project Animated Vector Graph Maps Surface Pressure Surface Temperature Cloud Cover & Precipitation Quick Menu
Select parameters with on/off switches Basic Menu gives 2 model choices
European Centre for Global Forecasting System Medium-Range Weather Forecasting US NOAA 9 km resolution 22 km resolution When you choose a forecast location Get third model choice Meteoblue
NEMS 4 km ECMWF default GFS Meteoblue Choose “Compare” to get all 3 models Left - click “Waves” to display 2 wave model choices
“WAM” (ECMWF) & “Wavewatch 3” (NOAA)
“Meteogram” Tide Forecasts METAR aviation report data
Predictwind Predictwind
Data from GFS & European model plus “proprietary model” to “nudge” these into a 1 km resolution
Post - processing using statistics
“PWG” NOAA’s GFS model “nudged”
“PWE” European model “nudged” Basic – fine for Standard - Pro - ocean most land based Free – 1 day’s data weather routing & temps & currents Web users GRIB files Data Table
Wind Speed
Direction
CAPE Wave Height Period
Wave Direction
Temp
Rainfall mm
Cloud Cover % P W Graphic Data French Farm April 11 – 17, 2018
Plots of PWG, PWE, GFS & ECMWF Isobar Maps MSLP & Precipitation Wind Maps
ECMWF model selected R = 50 km although model = 9 km Wave Maps Two Model Comparison (wind & isobars)
PW guidance: If models don’t agree, less reliability. If 3 models agree and 1 does not, go with the 3 My advice: if 2 un-nudged models don’t agree – go with ECMWF ECMWF GFS High Resolution = 1 km nudged models Only available for very near shore locations And not everywhere. See coverage map on website
Dots away from shore = 8 km resolution Offshore = 50 km
Dots close to shore = 1 km resolution “Nudging” Qualifications
“Post – processing” or “bias correction” Accepted statistical process (several methods) Often produces better results than raw model
Highly error prone in complex terrain (mountains, alpine areas etc)
Requires data input from a met station the further from an observation station, the worse the output high seas data less accurate than coastal
Models with Resolution > 10 km do not benefit from post processing High Res models consider physical processes better
Good at “nowcasting”: up to 6 hours ahead. Beyond 6 hrs. output may be worse than raw model. (software)
Need Standard ( $ 250 USD/yr) or Pro subscription ( $ 500 USD/yr)
Communication via SSB e mail (Sailmail, Winlink) or satellite provider
Product quality, same as land based web connection Wi Fi connection to smart phone, tablet, computer Voice, Email, GRIB files, GPS position reports Iridium - only truly world wide LEOS system (66 satellites) Not for internet browsing – too slow PW is not the only game in town … OCENS package can include weather GRIB file service Internet Browsing Fixed station broadband platform Voice & data
General Estimate Example… $ 4500 USD (+ GST & shipping)
Iridium Pilot
Plus air time University of Basel, Switzerland
Company formed 1986 - after agricultural chemical factory fire inadequate wind data
2 MB models with 10 variations for globe & regions 1 specific to NZ Also run 13 third party models
Free to public – ad supported Premium, no adds - $57 USD / yr Forecast Quality
Validations of model accuracy presented with every forecast
Temperature
First 12 hrs - 80% of temps ± 2° C from observed Next 2.5 days - 70% of all temps ± 2° C
Wind
First 2 days - 70% - 80% model agreement with observed
Precipitation
First 3 days - 75% - 85% of predictions ± 2 - 5 mm of observed
(Thunder storm & tropical rain quantity very limited accuracy) Model Verification
Model output from past 3, 6 or 7 days compared with actual observations Available for all forecast locations
Christchurch International Aero
7 Day Verification 7 day Forecast One Day Summary - 3 hour increments
“rainSPOT” – shows precipitation distribution with in a 25 x 25 km square One forecast day – hourly data 2 model runs per day for New Zealand with NEMS-NZ at 0700 & 1900 UTC
NEMS = NOAA model, superior to GFS & refined by MB Pointer over graphic displays description
Predictability bars Predictability Color Coding Very High - Dark green 80% High - Light green 65 - 70 % Medium - Yellow 55 - 50% Low - Orange 35 – 25% Very Low - Red 15 – 5%
Predictability bars If predictability = Medium, Low or Very low “Multimodel” may show why Compares 7 models for your location in 3, 6 or 7 day forecasts
Meteoblue model = dashed line “Multimodel” Displays
Temperature
Precipitation
Wind speed
Wind direction
Model color codes
NEMS 2-30 (purple) Includes New Zealand Animated Satellite Infra red Cloud Cover (past 2 hours) Basic but easy to use 7 day “Meteogram” 3 graphs: Temp, Precip, Wind 14 Day Meteogram Lots of Map Choices Surface Winds Over 100 Different Maps
17 primary / popular
13 temperature
12 clouds
15 precipitation
12 wind, waves & sea
17 air quality
10 METAR (observations for aviation)
12 specialty 250 hPa wind - jet stream Sea level Pressure Clouds, 3 hour precipitation Precipitation Probability % “Convective Clouds with Vertical Extent” Wave Height & Direction Manual Control of Forecast Increments “Cross Section” plots
Click CS to get cross section of your chosen location
Or draw your own path
Choose your view direction …
Top – Looking from South to North Bottom - looking from W to E 10 yrs of actual data @ closest “Climate Observed” observation station to your forecast location “Onawe” to Christchurch Int. Airport “Climate History” Indicates Typical Climate Patterns 30 years modeling for closest observation station to your forecast location
Precipitation & Temperature More Climate History Graphs Temperature (10 meters) Sun, Cloud and Precipitation Days
Precipitation Wind Rose Agro Sowing Meteogram Air Quality National Park, New Zealand National Park Hawaii SO₂ Kilauea volcano
Sulfur dioxide Standards US EPA Primary std. 1 hour daily max - 195 ug/m³ Secondary std. NTE more than 1 X / yr – 1300 ug/m³ Atmospheric Variables for Sky Visibility GRIB files for Offshore GRIB Files
“Gridded Information in Binary”
World Meteorology Organization 1988 data format National met services use GRIB’s to store & exchange data International grid system, defined by lat/long points
Binary data (0’s & 1’s) organized in a grid format Vector files / paths
Compressed for efficient transfer: internet, HF radio & satellite
“Open CPN” GRIB open source chart plotting software GFS from NOAA with isobars & wind arrows Predictwind GRIB on Predictwind GRIB viewer
Viewer download is free but PW data is not.
Offshore app needed $250 USD / yr xygrib.org GRIB viewer Open source viewer & service GFS model theyr.com GRIB Raymarine MFD uses theyr.com GRIB’s GFS free, $ for higher res products GRIB’s available for high & low resolution models High res = commercial subscription, many sources
Free GRIB’s: GFS & US Navy “NOGAPS” data (GFS generally better than NOGAPS)
GRIBS’s – direct output from models
Purely objective data
No Human input or guarantee of accuracy
Fine for planning
Not a recognised info source under GMDSS More GRIB Qualifications
Meteorological Features WF’s , CF’s, troughs, ridges etc. Do not appear on GRIB’s Exception - NOAA’s new North American GRIB’s
Any data presented between data points – interpolated
Graphically strong GRIB’s may look more accurate than they are Parting Thoughts…
Lots of great data & many ways to access it
But, do not believe claims of …
• Exceptional accuracy
• Precise high quality forecasts
• Incredible detail
• Accurate long – range forecasts
Additional Slides for further explanation of above HF Radio vs. Satellite Satellite Equipment cost ($ USD, no GST or shipping) Iridium Go! Total cost $1,100 or HF Radio Broadband terminal 4,500 (much faster connection SSB Icom M802 radio $2,000 than Iridium Go!) AT 140 tuner 500 Phone (popular Iridium 9555) 1,200 Back stay insulators Wi Fi router 100 (connect sat phone to & cable 500 Smartphone, tablet, computer) Pactor modem 1,800 Broadband total 5,800 HF radio total 4,800 Plus air time Example: prepay 400 min $ 549 /1.37 per min Other Considerations
HF radio Constraints Fixed broadcast schedules for weather faxes Signal propagation variability Benefits Communicate with other boats & ships Listen to nets
Satellite
Main constraint – air time cost Benefits World wide coverage (Iridium) 66 LEO satellites Populated world regions – Globalstar (not NZ or many SP islands)
Reliable voice & data anytime Very desirable if conditions are stressful
“GRIB Viewers”
Software to open & display data
No need to purchase. Good free software: GRIB.US Open CPN / opencpn.org Viewfax / NOAA Saildocs XYGrib / opengribs.org GRIBview / Theyr.com
Predictwind (viewer free, GRIB’s = subscription)
Selected subscription charting programs with GRIB viewers: Coastal Explorer, Deckman for Windows, Expedition, Maxsea, Nobeltec, Rayteck
GRIB Sources
Free NOAA – GFS
Subscription Services
gribfiles.com 6 month access to all models – 200 € Majority are for Europe, GFS is only model covering Pacific)
predictwind.com (need PW Standard or Pro account $ 250 USD / yr for Std)
theyr.com (low resolution GFS GRIB free, high res = $)
Major electronic nav. equipment suppliers Raymarine, Furuno, OCENS, MaxSea Getting GFS GRIB’s
Supplied by NOAA, no cost
Request via e mail from NOAA “Saildocs” To: [email protected]
Not hard but cumbersome & must be exact. Best understood by example.
Refer to:
Frank Singleton’s site www.mailasail.com
Winlink www.winlink.com
www.saildocs.com/gribinfo “Open CPN” opencpn.org
Open source software – free
Chart Plotter Navigation supporting GRIB charts Connect via HF radio or Satellite for GRIB downloads
Runs on standard PC or laptop Windows, Mac or Linux
Weather routing built in Have to download marine charts ahead of time Weather Satellite Image Reception On 137 MHz Need antenna, receiver, and software for computer NOAA broadcasts images directly from POES Polar Earth Orbiting Satellites & GOES Geostationary Operational Environmental Satellites Japan’s Meteorological Center / MTSA-1R also plus EUMETSAT ( but does not cover NZ or much of Pacific) APT Automatic Picture Transmission Receiver Wrasse WeSaCom APT-06
Wrasse MX 137 Yacht antenna Iridium coverage for GMDSS weather forecasts & warnings 66 LEOS satellites Commercial Weather Services
Forecast & routing
Communicate via e mail
Commanders Weather
Weather Guy
Worthwhile esp. for less experienced cruisers