Dicks Radar Copy

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Why We Need a CoastalWeather Radar

Cliff MassDepartment of Atmospheric Sciences

University of Washington


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Northwest Coastal Radar ProblemThe Pacific Northwest has the worst coastalradar coverage of any region of the lower 48-states.

There is virtually no radar coverage for thelower atmosphere over the coastal zone andthe near-shore waters.It is particularly disturbing that such poor coverage exists for a region of often intensestorms AND a great deal of military,shipping, fishing and other marine traffic.


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Weather Radar 101

Modern weather radars can see where it is precipitatingDoppler radars can also get the air velocityRadars can track storms, fronts, and other major featuresCan tell how much rain is falling over a broadareaincluding mountain slopes.An essential tool for the National Weather Serviceand other meteorologists.


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When Hurricane KatrinaApproached the Gulf Coast

Radar Clearly Showed the Threat


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The Problem


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The rightdiagramindicates theeffectivecoverage of theWeather Service radars(at 3-km,above meansea level), withhatchingindicatingsubstantial

blockage.


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Radar coverage for thelowest beam (.5 degreeelevation angle) for the

current network. Redareas indicate nocoverage below 8000 m(25,000 ft). Radar

coverage calculations byKen Westrick


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NO C overage Below 25,000 f t


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The Implications of Poor Coastal

Radar CoverageNorthwest forecasters often have a poor ideaof the structure of weather systems

approaching the area. There have been several major forecast failures in

the 0-24 h range that could have been mitigated if coastal radar coverage was better.

The ability to provide short-term forecasts(nowcasting) over western Oregon andWashington is greatly lessened.


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F ebruary 7, 2002

On the morning of 7F ebruary 2002 anintense low center moved into the central

Oregon coast, withabsolutely no warnings by the NationalWeather Service.Produced strong winds

with gusts exceeding70 mph


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A surprise storm insouthern Oregon on

F ebruary 7, 2002 causedmassive tree falls and

damage

NO WARNINGS!!


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The Implications of Poor Coastal Radar Coverage

With no low level Doppler wind andreflectivity from radar, critical warnings andweather guidance over the coastal zone aredegraded. No assistance for emergencysituations, pollutant spills, and the like.

When the New Carisa

grounded Near CoosBay, Oregon, therewas no radar coverageto help manage salvageoperations.


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The Implications of Poor Coastal Radar

CoverageThere is no radar coverage of the heavyorographic precipitation on the western and

southern sides of the Olympics and coastalmountains.thus, degrading flood and river forecasting.


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The Implications of Poor Coastal Radar

CoverageThere is a distinct lack of weather dataoffshore for use in initializing weather

prediction models along and off the coast.A coastal radar would provide bothDoppler winds and reflectivities (where it israining) that could be assimilated into themodels. Without such radars, future short-term forecast skill of weather featuresapproaching our coast will be limited.


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We Do Get Hurricane StrengthStorms

Major storms do occur here in the NW andwithout coastal radars we can not determinethe structure and position as well as weshould

Example: Columbus Day Storm of 1962:Winds Exceeded 150 mph in places withcatastrophic damage


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1921 Olympic Blow Down Storm


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An Extraordinary EventHurricane-F orce Winds Struck the EntireWashington Coast At North Head sustained (5 minute average)

winds reached 126 mph, with a maximum one-minute wind of 150 mph before the sensor failed.

At Tatoosh Island, 150 miles to the north, winds

reached 110 mph. At Astoria, on the south side of the Columbia,there were unofficial reports of gusts to 130mph.


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An Extraordinary Event

It was estimated that 80% of the mature timber near North Head was razed during this storm and7-8 BILLION board feet of timber was downedover coastal Washington eight times that blowndown by Mt. St. Helens, and roughly the entirecurrent annual harvest for the entire Pacific

Northwest today.


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As a result, this event has become known as theThe O lympic B lowdown S torm

In some areas over 40% of the trees were blown down


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The Most Extreme Northwest Windstorm: TheColumbus Day Windstorm of 12 October 1962


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The Big OneThe Columbus Day Storm was the most damaging

windstorm to strike the Pacific Northwest in 150 years.An extensive area, stretching from northern California to

southern British Columbia experienced hurricane-forcewinds, massive treefalls, and power outages.In Oregon and Washington, 46 died and 317 requiredhospitalization as a result of the storm.F ifteen billion board feet of timber worth 750 million $ weredowned, 53,000 homes were damaged, thousands of utility

poles were toppled, part of the roof of Portlands Multnomahstadium was torn off, and the twin 520 ft steel towers thatcarried the main power lines of Portland were crumpled.At the height of the storm approximately one million homeswere without power in the two states, and total damage wasconservatively estimated at a quarter of a billion (1962)dollars.


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Columbus Day 1962: At Cape Blanco there were150 mph with gusts to 179! Strongest winds on

bluffs and windward slopes of coastal orography


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F eb. 13, 1979: Winds over 100 kts destroyed the Hood Canal BridgeCost to replace: over 100 million dollars


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F ebruary13

1979:TheHoodCanalStorm


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The Solution: Acquisition of Additional Coastal Radars

By adding one or two coastal radars, the National Weather Service could greatlyimprove the current situation.Although the NWS radar (WSR-88D)production line is now closed, Enterprise

Electronics has a similar (if not better) product available (DWSR-8501S/K).Cost: Approximately $ 4.5 million per radar,

plus installation costs and maintenance.


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EnterpriseDWSR-8501S/K Doppler Radar.The National

Weather Servicehas already

purchased two

of these to fill intheir radar network.


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Now With Two New Radars


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Acquisition of Additional Coastal Radars

Ideally two radars would be acquired withone positioned on the central WA coast (e.g.,Westport) and the other on the centralOregon coast ( F lorence)If we could secure only one, Westport would

be the best choicesince it provides

coverage of entrances to both the ColumbiaRiver and the Strait.


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F or More Information Check the Web Site

http://www.atmos.washington.edu/~cliff/coastalradar.html


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None70%

Partial

7%

Full23%

Coverage over the Pacific Northwest at or below 2-km:Where the real weather is!

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