during the early 90s, the nws installed a network of powerful doppler weather radars, aka nexrad

The Status of the Weather Radar Acquisition for the Washington Coast

Cliff Mass Department of Atmospheric Sciences

University of Washington

During the early 90s,

the NWS installed a network of powerful Doppler Weather

radars, akaNEXRADWSR88D

NWS Radar Sites

But there was a major problem in the Pacific Northwest...

The two NW radars (Camano Island, WA and Portland, OR) were placed east of the Olympics and Coastal Mountains and thus the radar beams were generally blocked before they reached the coast.

Radar coverage for the lowest beam (.5 degree elevation angle) for the current network. Red areas indicate no coverage below 8000 m (25,000 ft). Radar coverage calculations byKen Westrick

The right diagram indicates the effective coverage of theWeather Service radars for all elevation angles at 10,000 ft above mean sea level, with hatching indicatingsubstantial blockage.

Northwest Coastal Radar Problem• The Pacific Northwest has the worst coastal

radar coverage of any region of the lower 48-states.

• There is virtually no radar coverage for the lower atmosphere over the coastal zone and the near-shore waters.

• Such poor coverage exists for a region of often intense storms AND a great deal of military, shipping, fishing and other marine traffic.

Years in the Wilderness

• For roughly ten years a number of local meteorologists called for the acquisition of coastal weather radars, with one positioned on the central Washington Coast.

• This went nowhere fast until two things happened in 2007 and 2008.

The First: The Big Storm of December 2-4, 2007

Dec. 2-3, 200720 inches in two days over coastal

terrain of SW Washington

The results: massive

landslides and river flooding

Pictures courtesy of WSDOT

Hurricane-Force Gusts for Nearly 24h

The Second: Senator Maria Cantwell

Senator Cantwell Not Only Appreciated the Importance of a Coastal Radar But Secured the

Funding

• 2 million dollars of stimulus funding• 7 million dollars in the 2009-2010 budget

Current Status

• The National Weather Service is now committed to installing the radar.

• It will be a power S-band (10-cm wavelength) radar like the current NEXRAD units.

• It will be a be a dual-polarized radar, which the current radars are not.

• (Dual-pol radars

Other Implications of Poor Coastal Radar Coverage

Northwest forecasters often have a poor idea of the structure of weather systems approaching the area.– The ability to provide short-term forecasts over

western Oregon and Washington is greatly lessened.

The Implications of Poor Coastal Radar Coverage• With no low level Doppler wind and

reflectivity from radar, critical warnings and weather guidance over the coastal zone are degraded. No assistance for emergency situations, pollutant spills, and the like.

When the New Carrisa grounded Near Coos Bay, Oregon, therewas no radar coverage to help manage salvage operations.

The Implications of Poor Coastal Radar Coverage

• There is no radar coverage of the heavy orographic precipitation on the western and southern sides of the Olympics and coastal mountains….thus, degrading flood and river forecasting.

Input from Larry Schick, Lead Forecaster, U.S.

Army Corps of Engineers

• “An additional one or two radar sites on the NW coast is imperative for managing risk and for confident flood control operations”

• “No doubt coastal radar would have helped in detecting precipitation and real time management of the floods in December.”

• “Coastal radar would help greatly in all our flood operations , not just the coastal areas, as we often need to know the timing of the end of the rain or increase in the Cascade projects as well. Coastal radar coverage would help us with that too and understanding near offshore precipitation conditions.”

The Implications of Poor Coastal Radar Coverage

• There is a distinct lack of high resolution weather data offshore for initializing weather prediction models. A coastal radar could provide such data. Without such radars, future short-term forecast skill of weather features approaching our coast will be limited.

• Weather radar information is invaluable for research, allowing the understanding of important local weather features.

The Solution: Acquisition of Additional Coastal Radars

Now With Two New Radars

Coverage for Lowest Elevation Angle (.5 degrees)

Acquisition of Additional Coastal Radars

• Ideally two radars would be acquired with one positioned on the central WA coast (e.g., Westport to Pacific Beach) and the other on the central Oregon coast (e.g.,Florence)

• If we could secure only one, a central WA coast radar should be the priority…since it provides coverage of entrances to the Columbia River and the Strait entrances, Gray’s Harbor, precipitation on the wet side of the Olympics, and is upstream of the densely populated Puget Sound region.

We have an idea of the advantages of such a radar, because one was in place for a research experiment…IMPROVE I, in January-February

2001.

Westport S-Pol Radar (January-February 2001)

Reflectivity from S-Pol radar at Westport 0031 UTC 2 Feb 2001 at 0.5 degree elevation

dBZ

National Weather Service Forecasters Found the Coastal

Radar Highly Useful During Those Two Months in 2001

AREA FORECAST DISCUSSIONNATIONAL WEATHER SERVICE SEATTLE WA325 PM PST THU JAN 4 2001

SATELLITE IMAGERY SHOWS COLD FRONT OFFSHORE NOW NEAR 133W...STILLWEST OF BUOY 5. WARM ADVECTION PRECIPITATION BEGAN ALONG THE COASTAROUND 18Z AND OVER THE INTERIOR AROUND 21Z. S-POL RADAR AT WESTPORT HAS SW WIND AT 40 KT BEGINNING AROUND 1500FEET. THIS COMBINED WITH JUICY AMS ASSOCIATED WITH THE FRONT WILL MAKE FOR HEAVY RAINFALL OVER THE OLYMPICS TONIGHT. THE WESTPORT RADAR IS ALREADY SHOWING MODERATE ECHOES JUST OFFSHORE. WILL CONTINUE FLOOD WATCH FOR THE SKOKOMISH RIVER. MODELS PRETTY CONSISTENT WITH THE

NATIONAL WEATHER SERVICE SEATTLE WA223 PM PST TUE JAN 23 2001

UPR LVL LOW IS SETTLING IN W OF THE OREGON CST NR 45N/133W AND PER12Z PROGS...WL HANG AROUND THRU WED NIGHT...BEFORE BEING ABSORBED ONTHU BY A 2ND UPR LVL LOW THAT DIGS SE TWD CA. AVN IS MDL OF CHOICE.WK FNTL BAND DRAPED NW-SE ACRS NW OREGON WL MOV SLOWLY NWD INTO W WATNGT WITH AREAS LGT RAIN BUT LOW ACCUMULATION. CONFIDENCE IN A LITTLELGT RAIN TNGT IS GOOD GIVEN S-POL RESEARCH RADAR AT KHQM SHOWG LGT ECHOES EXTENDING NNW ALG FNT TO ABT 35NM W QUILLAYUTE.

NATIONAL WEATHER SERVICE SEATTLE WA930 AM PST THU JAN 4 2001

SATELLITE IMAGERY SHOWS COLD FRONT OFFSHORE NOW NEAR 134W. SSMIIMAGERY OLD BUT IMAGERY FROM YESTERDAY SHOWED PW VALUES OVER 2 INCHESAND MAX RAINFALL RATES AROUND A HALF INCH AND HOUR ASSOCIATED WITHTHE FRONT. GIVEN THE CONNECTION TO THE TYPHOON IN THE WESTERN PACIFICTHIS IS NOT UNREASONABLE. 12Z MODEL RUNS CONSISTENT IN BRING FRONTTHROUGH WESTERN WASHINGTON 12Z-18Z FRIDAY. SOUTHWESTERLY 850 MB WINDSOF 40 KNOTS AHEAD OF THE FRONT MAKES FOR STRONG OROGRAPHICS ALONG THESOUTHERN SLOPES OF THE OLYMPICS TONIGHT BETWEEN 00Z-12Z. WILL KEEPWATCH FOR THE SKOKOMISH GOING. S-POL RADAR AT WESTPORT SHOWS LEADINGEDGE OF THE PRECIPITATION OUT AHEAD OF THE FRONT JUST WEST OF KHQM AT16Z. CURRENT TIMING BRINGS THIS PRECIPITATION INTO THE INTERIOR MIDTO LATE AFTERNOON. MORE COOL AIR BEHIND THIS FRONT THEN THE FRONTSTHAT WENT THROUGH THE PAST WEEK FOR SCATTERED SHOWERS FRIDAYAFTERNOON BUT MOST OF THE PRECIP WILL BE IN THE MOUNTAINS. SATURDAYSTILL LOOKS DRY WITH UPPER LEVEL RIDGE MOVING OVER THE AREA ANDOFFSHORE SURFACE PRESSURE GRADIENTS. LITTLE CHANGE TO CURRENTPACKAGE. FELTON

The Coastal Radar Helped During a Flooding Event

Weather Radar Greatly Improves Daily Lives

• Able to plan recreational activities or even bicycle commuting.

• Assists weather sensitive businesses from fishing and crabbing to construction, painting and forestry.

• Why should the coastal portion of Washington be denied these advantages?

Maritime Interests

• The coastal waters of Washington heavily traveled by both civilian and military vessels.

• Important fisheries offshore and alongshore.• Knowing weather is needed for safety.

Radar Costs

• The radar, with polarization option, would cost approximately four million dollars (including installation).

• Costs of land, site surveys, bringing in utilities, and spare parts are additional.

Growing Support for the Coastal Radar

• Northwest Weather Modeling Consortium• Friends of Gray’s Harbor• Crab Industry, Fishers, and Oystermen• Audubon Society• Port Blakely Tree Farms• Cities and Counties• Puget Sound Clean Air Agency• Editorials in major local papers

For More Information Checkthe Web Site

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

Analysis of Four Sites from SRI Report

• Information provided by Socorro Medina, Cliff Mass, and Bob Houze, University of Washington

Topography around possible radar locations

Exact location of sites (for Saddle and Langley hills these are

slightly different from our previous calculations) North Central Park (site 6): 46.985111 N, 123.724917 W

Langley Hill (site 12): 47.116139 N, 124.113639 W

Scar Hill (site 19): 46.858500 N, 123.698361 W

Saddle Hill (site 23): 47.062472 W, 124.112111 W

Terrain and 50 km range rings around radar locations(~1 km resolution terrain)

LangleyHill –Site 12

ScarHill –

Site 19

SaddleHill –

Site 23

N. CentralPark -Site 6

Beam-blockage simulations

The following slides present calculations of terrain beam-blockage (described in Lang et

al. 2009) for low-level elevation angles. They were conducted with ~ 1 km resolution terrain and assuming a 30 m tower. The

figures show 50 km rings.

Beam blockage at 0.0° elevation angle for different radar locations(using ~1 km resolution terrain and a 30 m tower)

LangleyHill –Site 12

ScarHill –

Site 19

SaddleHill –

Site 23

N. CentralPark -Site 6

Beam blockage at 0.5° elevation angle for different radar locations(using ~1 km resolution terrain and a 30 m tower)

LangleyHill –Site 12

ScarHill –

Site 19

SaddleHill –

Site 23

N. CentralPark -Site 6

Beam blockage at 1.0° elevation angle for different radar locations(using ~1 km resolution terrain and a 30 m tower)

LangleyHill –Site 12

ScarHill –

Site 19

SaddleHill –

Site 23

N. CentralPark -Site 6

Beam blockage at 1.5° elevation angle for different radar locations(using ~1 km resolution terrain and a 30 m tower)

LangleyHill –Site 12

ScarHill –

Site 19

SaddleHill –

Site 23

N. CentralPark -Site 6

Beam blockage at 2.0° elevation angle for different radar locations(using ~1 km resolution terrain and a 30 m tower)

LangleyHill –Site 12

ScarHill –

Site 19

SaddleHill –

Site 23

N. CentralPark -Site 6

Some Conclusions• Of these four sites, North Central Park and Scar Hill are clearly

inferior, with far greater blockage than the other two.• Langley Hill and Saddle Hill are both very similar and

promising, and the SRI report suggests both have accessible utilities. Each has its own positives and negatives. – Langley Hill has more blocking towards Puget Sound and is

forested. It is closer to the Olympics and affords better close-in radar coverage. Farther from SW Washington mountains.

– Saddle Hill has far few trees and less blocking towards Puget Sound. There is a cell tower there.

Comments

• Pacific Beach is perhaps the third choice. Certainly as good as Scar Hill and is closer to the Olympics (potentially better dual-pol coverage). However, it is further from the mountains of SW Washington—a negative. We don’t believe sea clutter will be a serious issue.

The END