National Weather Service

Skywarn (TM) spotter News

Summer 2008 Edition

From the National Weather Service - Seattle

March 2008 was cool with normal rainfall at Sea-Tac. Measurable rain fell on 19 days, there were only two warm days (58 and 60 for highs on the 9^th and 10^th) and temperatures averaged about three degrees below normal for the month. The last week of the month was unusually cool--the 28^th only saw a high of 42 degrees and the maximums averaged out to be a record cool week. Snow depths in the mountains were well above average, with snow depth ranging from 131” at Snoqualmie pass to 240” at Paradise Mount Rainier.

April was also cool—averaging just over 3 degrees below normal—one very warm day occurred and a record high of 79 was set on the 12^th. Precipitation was below normal, although there were again 19 days with measurable rainfall. A late season snow event on the night of April 18^th-19^th brought up to 9 inches of snow to some areas of the Puget Sound convergence zone.

May saw drier than normal weather and temperatures recovered to near normal. There was even a record breaking, although brief, hot spell when the mercury rose to highs in the 80s on the 16^th (with readings in the 90s on the coast) and then peaking with a high of 90 on the 17^th—with readings well into the 90s and even a few lower 100s in the interior of Western Washington closer to the Cascades. The ridge of high pressure responsible for the hot weather was not a typical summertime four-corners high, which build westward and then north from California. This was a temporary ridge of high pressure which amplified in response to an active weather pattern upstream in the Pacific. Indeed, after the heat, high temperatures sagged into the upper 50s and 60s for the last ten days of the month—summer had not quite arrived.

The first ten days of June were remarkably cool and wet across Western Washington. Highs were unusually cool with readings in the 50s nearly every day. In fact, for the first week in June, Seatac’s average high temperature was the coldest ever! A cold upper level low and vigorous cold front swept through the area the evening of June 10^th, numerous locations recorded peak wind gusts of 35 to 45 mph with the front. Heavy snow fell across the higher elevation of the mountains on several days in early June—even falling as low as the main Cascade passes on a couple of occasions.

What are the all-time recorded high temperatures for these locations? And do you the year it occurred? The answers are elsewhere in Skywarn (TM) Spotter News.

On June 1^st, the Evergreen State became the 32^nd state to join the growing nationwide Community Collaborative Rain, Hail and Snow network, or CoCoRaHS (pronounced Cocoa Rawz). CoCoRaHS is a non-profit, community-based network of volunteers of all ages and backgrounds working together to measure and report precipitation (rain, hail and snow).

CoCoRaHS is a supplemental observation network that began in the late 1990s in Fort Collins, Colorado following a major flash flood. CoCoRaHS allows volunteer precipitation observers to collect and enter their rainfall, snowfall, hail and snow reports via a web-based system. The data supplement current observation networks and are displayed on maps that can be accessed by anyone 24/7 on the Web.

Where do the precipitation reports go?
Precipitation varies significantly across Washington’s complex terrain. Now you can join the CoCoRaHS team and submit your precipitation reports on the web site <www.cocorahs.org>. The data are then displayed and organized for anyone to use, including the National Weather Service.

A thorough on-line training module is available on the CoCoRaHS web site. It includes proper gage siting techniques as well as other program information. You need to provide your own rain gage that you can purchase through CoCoRaHS for less than $30 including shipping.

Interested in becoming a CoCoRaHS observer?
Washington state CoCoRaHS is managed by the State Climatologist Office, the UW Atmospheric Sciences Department, and National Weather Service offices in Spokane, Seattle, Portland and Pendleton. Washington state officially began collecting and processing reports on June 1^st, just in time for a wet period in the first week. Nearly 100 people joined CoCoRaHS that first week and reported the rainfall in their backyard. So join CoCoRaHS now at www.cocorahs.org, You can learn more about the program on the web site and download an application. or complete the on-line version on the web site.

Yep, its been a cloudy, cool and seemingly wet spring. Yet, summer will get here with our warmest and driest time of the year. Usually our summer weather is tranquil. Yet once in a while, significant weather strikes.

Our typical hazardous summer weather events include thunderstorms, winds with marine ‘pushes’ and hot spells. Let’s look at each of these.

Thunderstorms produce lightning and potentially strong damaging winds, large hail, heavy rainfall amounts leading to flash or small stream flooding, funnel clouds and tornadoes. Remember your safety rules. If thunderstorms are in the forecast, be prepared. If one approaches, seek shelter now. Avoid using electrical appliances during the storm. If caught outdoors, find a low spot away from trees or other tall structures that lightning tends to strike.

The week of June 22-28 is National Lightning Safety Week this year. Visit http://www.lightningsafety.noaa.gov/ for more information about lightning. Remember – When Thunder Roars – Head Indoors.

Per your spotter criteria sheet, report strong wind, hail, heavy rainfall and tornado events when safe conditions permit. Report frequent lightning only when it follows a hot dry period, During cool damp weather, lightning reports are not necessary.

Our wildfire season usually gets started in July and runs until the fall storm season begins. Large wildfires are usually associated with lightning and windy conditions, particularly after an extended period of hot dry weather. If you notice smoke rising after a lightning strike, call 911 and report its location to the nearest fire department. They will respond quickly.

Our spring weather has been cool and rather wet, postponing the wildfire season a few weeks. Yet it has also helped generate a bumper crop of grasses and other fine fuels that will later cure and be ready to burn. Please avoid throwing burning materials out of your vehicle this fire season.

A marine push is a surge of cooler marine air from the Pacific Ocean that dramatically cools western Washington down in the wake of a warm or hot weather period. A marine push often brings windy conditions and much cooler air inland, We saw that following the hot May 17^th this spring when temperatures climbed into the 80s and lower 90s, then plunged back into the 50s the following day after a marine push.

Extended periods of hot weather are relatively rare in our area. However, when they do occur, the natives are not used to it and get restless. During these hot weather periods, be sure to drink plenty of water, avoid strenuous activities during the heat of the day, and find cooler locations like shade or an air conditioned building. A cooling down period will help reduce the stress on your body that heat can create, especially since about 90% of us do not have air conditioning in our homes and warm nights make for a less than restful night of sleep.

What is the summer weather outlook? The National Weather Service Climate Prediction Center’s (CPC) latest outlook shows increased odds on cooler than normal temperatures and near normal precipitation from July through September.

And beyond this summer, the outlook is for near normal temperatures and precipitation for this winter. The La Nina phenomenon that influenced this past winter has weakened and right now, it looks like we are headed toward a ‘neutral’ winter – meaning neither La Nina or El Nino.

For the latest CPC seasonal outlooks, visit the headline on our web site at weather.gov/seattle/ In addition, for the latest weather forecasts and conditions, always visit our web site and listen to a NOAA Weather Radio station near you. If significant summer weather is on tap, you’ll be ready for it. Enjoy your summer!

Many weather spotters are obtaining anemometers these days in their effort to help know and report more accurate wind reports. One key question we get from these folks is where do I install the system for accurate wind reports? Greg Carstens – Pierce 3, offered the following found on-line at www.weathershack.com/education/anemometer.html

An anemometer should be located in a spot where the wind flows freely and is not influenced by nearby objects and obstructions, like a house or trees. The World Meteorological Organization has set the international standard height for wind measurement devices at 10 meters or 33 feet above ground, with no obstructions at or above this level. This height is not easy to achieve at your home! So striking a compromise is likely the best alternative, depending on what is around your home.

Wind observations taken at 7 meters or 23 feet are accurate enough for the National Weather Service. With wireless systems these days, you can set up your anemometer on a pole out in an open area away from your house and trees. For rooftop installations, the minimum height to avoid anomalous winds caused by the roof itself is 3 meters or 10 feet above the most exposed part or top of the roof.

Accuracy of the wind speed indicator is not just a matter of height. Local obstructions like nearby mature trees, house and other buildings all have the potential of impacting wind readings. This is unfortunately the reality of taking wind measurements and the choice on how to address it is ultimately yours. And be sure to install your anemometer safely as well!

Spotter Training Update - Skywarn (TM) Weather Spotter Training was held in Island, Kitsap and King counties this spring. About 180 people attended these training sessions – welcome to the Skywarn (TM) team!

More spotter training is planned for this fall. Initial targeted areas include Skagit, western Lewis, Jefferson and Thurston counties. As this summer wears on, check our web site at www.weather.gov/seattle under the Spotters link or the headline for training announcements as they are developed.

Pacific NW Weather Scramble Date Set - The date for the golf outing has been set for Sat Aug 23, again at Ft Lewis Golf Course just off Interstate-5 at exit 116 south of Tacoma. The event is a fun networking opportunity for those in the weather community, including weather spotters. Entries are now available. If interested in an entry, contact Ted Buehner at ted.buehner@noaa.gov

New NOAA Weather Radio Station Now On The Air - Washington’s newest NOAA Weather Radio station became official near the end of May after a month of testing. The new station is located in the upper Cowlitz river basin serving the region from near Packwood west past Randle. The station is a partnership with Lewis County and operates on a frequency of 162.425 MHz.

This station is the 23^rd NOAA Weather Radio station serving the Evergreen State, reaching now over 95% of the state’s population. NOAA Weather Radio is an all-hazards warning system and a key part of the Emergency Alert System or EAS. So not only do you receive weather-related warning messages, but also for hazards like tsunami, volcano, wildfire evacuations, Amber alerts and 911 outages.

You have a smoke detector in your home. But do you have an all-hazards weather radio receiver? This September will be Weather Radio Awareness Month in Washington. As a part of the campaign, many weather radio vendors will offer discounts on weather radio receivers, your opportunity to get your radios. Look for much more information on our web site this September at weather.gov/seattle/

How Do I Report Severe Weather When I Am Traveling Away From Home? - A new nationwide toll-free number has been created to permit anyone to report hazardous or severe weather when they are on the road. The phone number is 877-633-6772.

The toll-free number has menu driven software, asking questions like what kind of weather are you reporting, and where you are via either latitude/longitude or zip code. Once your report is done, the software then automatically sends your report to the appropriate National Weather Service forecast office for that area.

This program was born from the nationwide Trucker Watcher program, a program initiated by Sean Kaier – a Snohomish county spotter. Now any Skywarn (TM) weather spotter can report severe weather when they are away from home too!