Basic Weather Safety for Chicago boaters

Matt Gallagher

What you need to know when you go beyond the cribs

This presentation available for download at www.wxchicago.com Always monitor and heed official warnings by the US Weather Service, Environment Canada and other governmental meteorological services © 2020 WXChicago, LLC Topics

• Hazards you face - this is about safety

• The weather: Big Picture and Small

• Building a personal forecast routine

• Additional ways to learn Identifying Hazards…

• What is the likelihood of severe weather threatening the safety of my crew or boat?

• What type of severe weather threat will I be facing?

• What will the timing be?

• Types of hazards:

• Wind

• Waves

• Storms …Begins with the big picture (synoptic) setup

• What’s happening in the big picture?

• How is that likely to change during the cruise or race?

• How will that affect my routing or strategy?

• What threats are likely? Big picture (synoptic) setup

• Maps

• Free government sources of information

• The NWS is your friend!

• Paid services and model data

• Local Media Fronts—separate air masses

Cold Front Warm Front

• • Cold air approaching Cold air Retreating • Wind shift to W/NW • Wind shift to SW • Source of lift, can lead to severe storms • Often cloudy, wet

Stationary Front Occluded Front

• Cold front caught up • Neither air mass moving to warm front

• Light wind • Signals beginning of end of the L • ? Stratus precip?

• Heavy precipitation Weather Models-- Synoptic

• Computer representation of atmosphere • No human intervention! • Limited in temporal and physical resolution • What you need to know to interpret model data • When was it initialized? • When is it valid? • Analysis vs forecast • What model am I viewing? • What is the resolution?

ALL MODELS ARE WRONG Wind

• NOAA standard is 10-m wind

• Wind speed is average over past 2 minutes

• Gust is the instantaneous speed, must be >10kts over wind speed and in last 10 minutes

• Peak wind is the maximum instantaneous wind during the entire period since last observation (hourly), must be >25kts Speed Specification Force (mph) (knots) Description (sea) (land) 0 0-1 0-1 Calm Sea like a mirror Smoke rises vertically 1 1-3 1-3 Light Air Ripples, no crests Smoke drift, but wind vanes do not move 2 4-7 4-6 Light Breeze Small, short wavelets, Crests do not break, have Leaves rustle, felt on face, vanes move glassy appearance 3 8-12 7-10 Gentle Breeze Large wavelets, crests begin to break. Leaves and small twigs in constant motion. 4 13-18 11-16 Moderate Breeze Small waves, becoming larger. Frequent white caps. Dust and loose paper moved, small branches moved. 5 19-24 17-21 Fresh Breeze Moderate waves, many whitecaps. Small trees in leaf begin to sway.

6 25-31 22-27 Strong Breeze Large waves begin to form, extensive white foam Large branches in motion. Difficulty crests. using umbrellas. 7 32-38 28-33 Near Sea heaps up and white foam from breaking waves Whole trees in motion. Inconvenience blown in streaks. felt while walking.

8 39-46 34-40 Gale Moderately high waves of greater length. Twigs broken off trees. 9 47-54 41-47 Severe Gale High waves. Crests of waves begin to topple, Slight structural damage may occur. tumble, roll over. Spray may affect visibility. Roofing tiles blown off. Ground littered with many small twigs/broken branches. 10 55-63 48-55 Storm Very high waves with long overhanging crests. Sea Small live trees uprooted, structural surface takes on white appearance. and vegetative damage. 11 64-72 56-63 Violent Storm Exceptionally high waves. Small and medium sized Large live trees uprooted. Widespread ships might be for a time lost to view behind waves. structural damage. 12 72-83 64-71 Hurricane Air filled with foam and spray. Sea completely Severe and extensive damage. white with driving spray. Windows broken. Roofs peeled off. Mobile homes overturned. Representing wind on a map

• Wind Barbs (left)

• Streamlines (below)

• More information The Station Model

For more information about an item marked with a (*), click on the appropriate link

: [Weather] [Wind] [Sea-Level pressure] [Pressure trend] [Sky cover] Waves

• Significant wave height = average of the largest 1/3 of all waves. • Individual waves can be 2x the SWH • Deep water swell differs from lake waves • Depth at which breakers will form / safe water depth= 2.5 x (maximum forecast swell + wind-wave height) Lesson from the 1979 Fastnet - Waves are what damage boats! Wind + fetch = waves Sea state forecasts

• NOAA radio

• NWS Website

• GLERL Storms Single Cell (Pulse) Storms

• Most common during summer

• Occur when wind shear is weak

• Typically last 30-60 mins

• Minimal severe threat

– Brief, localized wind damage or hail, if anything Multicell Storms

• Most common spring through early autumn

• Usually occur with moderate wind shear

• Can last hours to more than a day Supercell

Supercell Storms

• Can last for many hours

• Threats include:

– tornadoes

– large hail

– damaging winds

• Produce most large hail & significant tornadoes Squall Line

• Long line - broken or unbroken - of thunderstorms

• “Bowing” of line often indicates strongest part of squall line - damaging straight-line winds

• Gust front leading the line of storms on radar

• Greatest danger for solid line is straight-line wind

• Greatest danger for broken line is Gust Fronts / Outflow Boundaries • Ahead of the main squall or cells • Gusty / cooler air, wind shift, often a pressure jump – mini cold front Finding out about hazards

•

• Government websites

• www.spc.noaa.gov

• For Chicago area: www.weather.gov/lot NWS Definitions

Gale Warning: A warning of sustained winds in the range 34 to 47 knots (KT) inclusive either predicted or occurring not associated with tropical cyclones.

Gust: A rapid fluctuation of wind speed with variations of 10 KT or more between peaks and lulls.

Marine Weather Statement: A product to provide mariners with details on significant or potentially hazardous conditions not otherwise covered in existing marine warnings and forecasts.

Small Craft Advisory: An advisory in coastal waters for winds from 20 to 33 KT inclusive and/or for seas, either predicted or occurring, that are considered potentially hazardous to small boats. There is no legal definition for "small craft." Note – may be changing in 2020.

Special Marine Warning: A severe local affecting coastal water areas, or a warning of potentially hazardous weather conditions usually of short duration (2 hours or less) and producing wind speeds of 34 KT or more that is not adequately covered by existing marine warnings. Also, this product is issued for waterspouts, either predicted or occurring.

Storm Warning: A warning of sustained winds of 48 KT or more, either predicted or occurring, not associated with tropical cyclones.

Sustained Wind: The wind speed obtained by averaging observed values over a period of at least 1 minute.

Waterspout: A rotating column of air, usually pendant from a cumulus or cumulonimbus cloud, that forms over water and whose circulation extends to the surface. NOAA Weather Radio

• Best source of hazard information, free and promptly and continuously updated

• But….

• Have to know their marine zones

• Have to know the right channel

• Have to know how your radio works

• Be careful of SAME coding Great Lakes NWS Info

• Chicago NWS Marine: https://www.weather.gov/lot/marine

• Great Lakes Marine Portal: https://www.weather.gov/greatlakes

• Great Lakes Marine Portal (Mobile): https://www.weather.gov/dlh/anchord

• GLERL Great Lakes Costal Forecast System: https://www.glerl.noaa.gov/res/glcfs/

• GLERL Data Page: https://www.glerl.noaa.gov/data/ Other government websites

• Climate Prediction Center (CPC)

• Long-term probabilities for above or below average temp and precipitation out to 3 months

• Weather Prediction Center (WPC)

• National forecasts - synoptic maps out to 7 days

• Storm Prediction Center (SPC)

• Hazard forecasts - Severe WX out to 8 days

• Local NWS Forecast Office

• Local area forecasts of all types

• Marine forecasts issued by certain offices only (e.g. Milwaukee) Planning a cruise

• When do I go?

• How do I get there?

• How can I keep up to date on the way? Before you go

• Develop a personal forecast routine

• Learn about the weather Departure planning

• When do I go to get there?

• Quickly

• Comfortably

• Safely Sources of departure planning info

• Predictwind (paid)

• Professional weather routers (paid)

• Various websites Getting information on the water

• NOAA Weather Radio

• Cellular-based

• Satellite based Personal Forecasting Routine

• Get a handle on the big picture

• Know what resources you can access

• Observe the weather

• Adjust the forecast for what you observe One-two weeks in advance of departure

• Start looking at big picture forecast - WPC, commercial providers

• Advanced work - 500mb charts and forecasts

• Longer-range models - GFS, Euro, GEM

• Goal - Get a sense of what is coming Two-three days before departure • Shorter range models (NAM) start to come into range

• Mid-range models (GFS, Euro) have greater validity

• Start looking at synoptic setup for the race

• Start running routings using Expedition or the like

• Brief the crew on what’s coming (sail selection, clothing and equipment)

• Goal: Understanding big-picture weather patterns and potential hazards you’ll face One day before departure

• Talk with weather router if you have one

• Run routings and develop strategy based on mesoscale models (NAM)

• Communicate to your crew

• Sail selection and gear

• Potential hazards Day of departure

• Look at short-term models (HRRR, 4km NAM)

• Start listening to NOAA Weather Radio - establish a schedule

• Implement initial strategy based on routings While at sea

• Depends on length and distance offshore

• Focus on hazards: NOAA Weather Radio, SiriusXM

• Focus on wind: cellular or satellite data if available

• GRIBS - know the schedule, recognize limitations

• Make observations of what you see, compare to forecast Keep a weather log

• Log your observations - every hour / 4 hours / watch change

• What to record?

• Cloud cover / description

• Wind speed / direction / tendency

• Temperature (air & water)

• Sea state

• Barometer

• USPS Weather Log (PDF or XLS) Marine Barometers

• Barometric pressure and tendency

• Types:

• Analog vs Digital

• Recording vs non recording

• Best: precision digital recording barometer Learning more Books

Burch, Modern Marine Weather - Best comprehensive text aimed at boaters

Jourdane, Modern Weather for Sailors - Another decent option for boaters

Aherns, Today Good introductory college-level text Classes and seminars

• Sailing Weather Service (Chris Bedford)

• Fairly specialized, more advanced

• LakeErieWX (Mark Thornton)

• Great introductory and specialized courses

• NorthU

• Online courses, featuring Expedition. Peter Isler teaches many Online Learning

• Penn State Online Weather Forecasting Certificate

• UCAR “Met-Ed” / Comet Apps

• Radarscope (iOS)(Android)

• Radarscope (Mac)

• GRLevel3 / GRLevel 2 (Windows)

• Expedition (Windows)

• Predictwind (Mac/Win/iOS)

• LuckGrib (Mac/iOS)