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, aka
NEXRAD
WSR88D
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 by
Ken Westrick
The right
diagram indicates
the effective
coverage of the
Weather Service
radars for all
elevation angles
at 10,000 ft
above mean sea
level, with
hatching
indicating
substantial
blockage.
Northwest Coastal Radar Problem
• The Pacific Northwest has the worst coastal
radar coverage of any region of the lower 48states.
• 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, 2007
20 inches in two
days over coastal
terrain of SW
Washington
Pictures courtesy of WSDOT
The results:
massive
landslides
and river
flooding
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, there
was 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
Coverage for Lowest Elevation Angle (.5 degrees)
Now
With Two New Radars
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 DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
325 PM PST THU JAN 4 2001
SATELLITE IMAGERY SHOWS COLD FRONT OFFSHORE NOW NEAR 133W...STILL
WEST OF BUOY 5. WARM ADVECTION PRECIPITATION BEGAN ALONG THE COAST
AROUND 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 WA
223 PM PST TUE JAN 23 2001
UPR LVL LOW IS SETTLING IN W OF THE OREGON CST NR 45N/133W AND PER
12Z PROGS...WL HANG AROUND THRU WED NIGHT...BEFORE BEING ABSORBED ON
THU 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 WA
TNGT WITH AREAS LGT RAIN BUT LOW ACCUMULATION. CONFIDENCE IN A LITTLE
LGT RAIN TNGT IS GOOD GIVEN S-POL RESEARCH RADAR AT KHQM SHOWG LGT ECHOES
EXTENDING NNW ALG FNT TO ABT 35NM W QUILLAYUTE.
The Coastal Radar Helped During a Flooding Event
NATIONAL WEATHER SERVICE SEATTLE WA
930 AM PST THU JAN 4 2001
SATELLITE IMAGERY SHOWS COLD FRONT OFFSHORE NOW NEAR 134W. SSMI
IMAGERY OLD BUT IMAGERY FROM YESTERDAY SHOWED PW VALUES OVER 2 INCHES
AND MAX RAINFALL RATES AROUND A HALF INCH AND HOUR ASSOCIATED WITH
THE FRONT. GIVEN THE CONNECTION TO THE TYPHOON IN THE WESTERN PACIFIC
THIS IS NOT UNREASONABLE. 12Z MODEL RUNS CONSISTENT IN BRING FRONT
THROUGH WESTERN WASHINGTON 12Z-18Z FRIDAY. SOUTHWESTERLY 850 MB WINDS
OF 40 KNOTS AHEAD OF THE FRONT MAKES FOR STRONG OROGRAPHICS ALONG THE
SOUTHERN SLOPES OF THE OLYMPICS TONIGHT BETWEEN 00Z-12Z. WILL KEEP
WATCH FOR THE SKOKOMISH GOING. S-POL RADAR AT WESTPORT SHOWS LEADING
EDGE OF THE PRECIPITATION OUT AHEAD OF THE FRONT JUST WEST OF KHQM AT
16Z. CURRENT TIMING BRINGS THIS PRECIPITATION INTO THE INTERIOR MID
TO LATE AFTERNOON. MORE COOL AIR BEHIND THIS FRONT THEN THE FRONTS
THAT WENT THROUGH THE PAST WEEK FOR SCATTERED SHOWERS FRIDAY
AFTERNOON BUT MOST OF THE PRECIP WILL BE IN THE MOUNTAINS. SATURDAY
STILL LOOKS DRY WITH UPPER LEVEL RIDGE MOVING OVER THE AREA AND
OFFSHORE SURFACE PRESSURE GRADIENTS. LITTLE CHANGE TO CURRENT
PACKAGE. FELTON
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 Check
the 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
North Central Park calculations)
(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)
N. Central
Park Site 6
Scar
Hill –
Site 19
Langley
Hill –
Site 12
Saddle
Hill –
Site 23
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)
N. Central
Park Site 6
Scar
Hill –
Site 19
Langley
Hill –
Site 12
Saddle
Hill –
Site 23
Beam blockage at 0.5° elevation angle for different radar locations
(using ~1 km resolution terrain and a 30 m tower)
N. Central
Park Site 6
Scar
Hill –
Site 19
Langley
Hill –
Site 12
Saddle
Hill –
Site 23
Beam blockage at 1.0° elevation angle for different radar locations
(using ~1 km resolution terrain and a 30 m tower)
N. Central
Park Site 6
Scar
Hill –
Site 19
Langley
Hill –
Site 12
Saddle
Hill –
Site 23
Beam blockage at 1.5° elevation angle for different radar locations
(using ~1 km resolution terrain and a 30 m tower)
N. Central
Park Site 6
Scar
Hill –
Site 19
Langley
Hill –
Site 12
Saddle
Hill –
Site 23
Beam blockage at 2.0° elevation angle for different radar locations
(using ~1 km resolution terrain and a 30 m tower)
N. Central
Park Site 6
Scar
Hill –
Site 19
Langley
Hill –
Site 12
Saddle
Hill –
Site 23
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