Sunday, September 19, 2010

Northwest Monsoon

I have been amazed by the amount of rainfall falling around here over the past two days, with a number of locations getting the equivalent of an entire September's rainfall in 48hr! Warm, humid, and tropical. At my home in north Seattle I had 1.1 inches the first day and 1.05 inches the second! The ground is saturated.

Take a look at the 48-h rainfall analysis from the Seattle Rainwatch web sight (built by the UW and sponsored by the City--Seattle Public Utilities--to allow them to deal with heavy rainfall situations, http://www.atmos.washington.edu/SPU/). Areas from Seattle extending back to Tahoma had over two inches.Here is a wide view...keep in mind Rainwatch is based on calibrating radar imagery using rain gauges and thus is not useful where terrain blockage is significant (over the Cascades, WA Coast for example). The heaviest rain was apparently near Olympia.Olympia has accumulated 4.1 inches of rain in just the past 4 days and 5.3 inches over the past 31 days. September normal at Olympia is 2.0 inches for the entire month.

Over the past 4 days SeaTac has recorded 3.2 inches of rain, normal for the entire month is 1.7 inches. Want more? For the calendar day yesterday Seattle set a new daily record (.78 inches) ...old record .57 inches in 1983. Want even more? So far this month (ending midnight) Sea Tac has received 3.74 inches, which IS THE WETTEST
18 days on record for September at that location. Olympia has the same claim. The all-time wettest Sept for Sea Tac is 5.95 inches and 7.59 inches for Olympia. A really good chance we will break these records.

If you have a sprinkler system, better turn it off.

I was planning on getting my house painted this fall...I have had second thoughts with all this rain!

Why has it been so wet? For several days we have had a persistent configuration of the upper level flow with a low offshore and southwesterly flow over us and Oregon (it has been even worse down there!). With strong SW flow we have had a warm, moist, unstable air streaming over us for days.


Latest NWS Statement released Monday AM:
835 NOUS46 KSEW 201154
PNSSEW

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE SEATTLE WA
450 AM PDT MON SEP 20 2010
..WET LAST FEW DAYS FOR WESTERN WASHINGTON ESPECIALLY THE PUGET SOUND REGION...

NUMEROUS PRECIPITATION RECORDS WERE SET DURING THE LAST FEW DAYS OVER THE INTERIOR OF WESTERN WASHINGTON.

SEATTLE

THE SEATTLE-TACOMA AIRPORT RAIN TOTAL FOR THE LAST FOUR DAYS WAS 3.23 INCHES ( 0.60 ON THE 16TH...1.49 INCHES ON THE 17TH...0.78 INCHES ON THE 18TH AND 0.36 INCHES ON THE 19TH ). NORMAL FOR THE ENTIRE MONTH OF SEPTEMBER IS 1.63 INCHES SO NEARLY 200 PERCENT OF THE MONTHLY NORMAL WAS RECORDED IN THE LAST FOUR DAYS. 3.23 INCHES WOULD BE THE 12TH WETTEST SEPTEMBER ON RECORD AT SEATTLE-TACOMA AIRPORT IN THE 66 YEARS RECORDS HAVE BEEN KEPT AT THE AIRPORT
( RECORDS STARTED IN 1945 ).

DAILY RAINFALL RECORDS WERE SET ON THE 17TH AND 18TH

17TH 1.49 INCHES...OLD RECORD 1.26 INCHES SET IN 1969
18TH 0.78 INCHES...OLD RECORD 0.57 INCHES SET IN 1983

RECORD ONE HOUR AND TWO HOUR RAINFALL FOR SEPTEMBER WERE SET.

11 PM TO MIDNIGHT ON THE 17TH 0.63 INCHES (OLD RECORD 0.54 9/8/79)
11 PM 17TH TO 1 AM ON THE 18TH 0.94 INCHES (OLD RECORD 0.60 9/22/78)

RECORD THREE DAY SEPTEMBER RAINFALL RECORD WAS SET 16TH THROUGH THE 18TH

2.87 INCHES...OLD RECORD 2.82 INCHES SEPTEMBER 20-22 1972.

RECORD FOUR DAY SEPTEMBER RAINFALL RECORD WAS SET 16TH THROUGH THE 19TH

3.23 INCHES...OLD RECORD 3.10 INCHES SEPTEMBER 19-22 1972

IT WAS THE SECOND WETTEST TWO DAY TOTAL ON THE 17TH AND 18TH...
2.27 INCHES. RECORD 2.36 INCHES SEPTEMBER 22 AND 23 1978.
THE 1.49 INCHES ON SEPTEMBER 17TH WAS THE FOURTH WETTEST SEPTEMBER DAY ON RECORD AT SEATTLE-TACOMA AIRPORT SURPASSED ONLY BY 1.65 INCHES ON SEPTEMBER 22ND 1978 AND SEPTEMBER 30TH 1953 AND 1.51 INCHES ON SEPTEMBER 26TH 1948.

MONTHLY RAINFALL TOTAL THROUGH THE 19TH AT SEATTLE-TACOMA AIRPORT IS 4.10 INCHES. THIS IS CURRENTLY TIED FOR THE FOURTH WETTEST SEPTEMBER ON RECORD. THE RECORD IS 5.95 INCHES SET IN 1978.

TOP 5 WETTEST SEPTEMBERS AT SEATTLE-TACOMA AIRPORT

1. 5.95 INCHES (1978)
2. 5.57 INCHES (1969)
3. 4.60 INCHES (1959)
4. 4.10 INCHES (1972) AND 2010.

THE 4.10 INCHES THROUGH THE 19TH IS THE WETTEST FIRST 19 DAYS OF THE MONTH ON RECORD SURPASSING THE PREVIOUS RECORD OF 3.10 INCHES SET IN 1959.

OLYMPIA

THE OLYMPIA AIRPORT RAIN TOTAL FROM THE 15TH THROUGH THE 18TH WAS 4.09 INCHES ( 0.66 ON THE 15TH...0.91 INCHES ON THE 16TH...1.67 INCHES ON THE 17TH AND 0.85 INCHES ON THE 18TH ). NORMAL FOR THE ENTIRE MONTH OF SEPTEMBER IS 2.03 INCHES SO OVER 200 PERCENT OF THE MONTHLY NORMAL WAS RECORDED BETWEEN THE 15TH AND 18TH. 4.09 INCHES WOULD BE THE 8TH WETTEST SEPTEMBER ON RECORD AT OLYMPIA AIRPORT IN THE 63 YEARS RECORDS HAVE BEEN KEPT AT THE AIRPORT ( RECORDS STARTED IN 1948 ).

DAILY RAINFALL RECORDS WERE SET ON THE 17TH AND 18TH

17TH 1.67 INCHES...OLD RECORD 1.13 INCHES SET IN 1969
18TH 0.85 INCHES...OLD RECORD 0.75 INCHES SET IN 1983

THE 17TH WAS THE WETTEST SEPTEMBER DAY ON RECORD AT OLYMPIA AIRPORT BREAKING THE RECORD OF 1.54 INCHES SET SEPTEMBER 6TH 2009.

RECORD THREE DAY SEPTEMBER RAINFALL RECORD WAS SET 16TH THROUGH THE 18TH

3.43 INCHES...OLD RECORD 3.24 INCHES SEPTEMBER 15TH-17TH 2010. OLD RECORD BEFORE THAT 3.14 INCHES SEPTEMBER 20-22 1972.

RECORD FOUR DAY SEPTEMBER RAINFALL RECORD WAS SET 15TH THROUGH THE 18TH

4.09 INCHES...OLD RECORD 3.54 INCHES SEPTEMBER 20-23 1972

IT WAS THE THIRD WETTEST TWO DAY TOTAL ON THE 16TH AND 17TH...2.58 INCHES. RECORD 2.66 INCHES SEPTEMBER 22 AND 23 1978...SECOND
2.62 INCHES SEPTEMBER 20TH AND 21ST 1972.

MONTHLY RAINFALL TOTAL THROUGH THE 19TH AT OLYMPIA AIRPORT IS 4.95 INCHES. THIS IS CURRENTLY THE FOURTH WETTEST SEPTEMBER ON RECORD. THE RECORD IS 7.95 INCHES SET IN 1978.

TOP 5 WETTEST SEPTEMBERS AT OLYMPIA AIRPORT

1. 7.59 INCHES (1978)
2. 5.23 INCHES (1969)
3. 5.04 INCHES (1972)
4. 4.95 INCHES 2010
5. 4.58 INCHES (1977)

THE 4.10 INCHES THROUGH THE 19TH IS THE WETTEST FIRST 19 DAYS OF THE MONTH ON RECORD SURPASSING THE PREVIOUS RECORD OF 4.00 INCHES SET IN 1978.

$$

FELTON

26 comments:

Donna & Chris said...

I emptied my rain gauge yesterday (beautiful day!) prior to the evening rain -- 2 inches for the past week, which is a lot. Then this morning I noticed another full inch! That is a HUGE amount of rain, I agree. My lawn is looking pretty lush.

I love setting records but not this kind in September. Sigh.

Michael said...

Cliff, you fool! You have now awakened the NW rain gods to bring even more our way. Just this last hour we have had downpours in the San Juan Islands like I have never seen. Three major storms tracked over Orcas producing over an inch of rain since 9am. What hath you wrought?

MarkM said...

The forecast discussion from NWS talks about T-storm development in the opposite direction of T-storm motion. What does that mean and what's its significance?

John Franklin said...

Cliff:
In your previous post you state that "providing frequent updates on current and expected weather is a hugely important area for development". Was wondering what you meant exactly by "development". As you probably know it is development that is causing most of the natural resource issues we face in the Pacific Northwest - like the destruction of the Sound, etc.

I know the major role of the UW is to provide services for the state's economic engine but there are people who live in the Northwest who don't see "development" as being intrinsically good.

Daniel said...

Cliff I feel your pain about the paint. we are waiting for it to stop raining enough to get the tarps to hold so we can fix the hole in the roof. so we can paint the Inside of our boat. and about the humidity, Dehumidifier and AC unit running and not keeping up.
Dan

october52 said...

It looks like November out there!

Targhee said...

I'm a volunteer observer for Cocarahs in Tacoma. This morning: 0.89 inches for previous 24 hours; yesterday AM emptied 1.71 inches covering Friday 7am-Sat 7am. Greater than the Rainwatch estimates. If you go to Cocorahs, you see right along the immediate shoreline, heavy totals. But, going just 10 miles inland, amounts drop off to less than 0.25 inches or so.

As a skier, am hoping this continues, albeit in the form of much cooler air...

Targhee said...

2.70 inches rain in north Tacoma, near UPS and Proctor. I'm a Cococahs observer, so I've seen the high totals along the immediate shore.

Jenny said...

We started painting our house at the end of August in hopes that September would live up to its normal pattern of moderate temps and little rain. Why I was thinking that with the crazy summer weather we had, I don't know. It's only 1/2 way done and looks like it will stay that way! Even if we do get a few more sunny days, it won't be enough to dry things out. Bummer.

analogkid said...

@John Franklin - I believe by "development", he meant continued work and/or progress towards better acute, or short time scale, updates to the current forecasts. Development refers to NWS/other forecasting personnel in their training/preparations to carry out these functions better.
I do not believe it was a reference to developing our area as in homebuilding or expansion.

Kevin Purcell said...

John Franklin: By "development" I think Cliff means the improvement ("development") of methods to communicate weather forecasts cleary to the public. This is one of Cliff's research interests.

development does have many meanings and most not concerned with building houses.

Chris and Amy's story said...

VERY heavy rain, out of nowhere, here in Skagit County. Reminds me of monsoon season in the Four Corners area. Crazy!

natchrl8r said...

You're catching the brunt of it this time, Seattle. Here in Bellingham we've had a few light showers but nothing to write home about: Less than 1.5 inches in 72 hours...

dampscribbler said...

Howdy from Portland! I've got friends up there in Seattle who link to your blog regularly, so I enjoy peeking in and getting some insight, even though things are slightly different down here. (Not often very different, though.)

I'm wondering if you have any thoughts about this winter's forecast based on historical comparisons (if there are any). In other words, do we have other cool, dry summers to compare this year to in order to try to predict whether this winter will be colder, warmer, drier, wetter than average? My guess for this winter (based entirely on conjecture) is wetter and warmer than average.

Voyage to Tonga said...

We are in the midst of painting our house, every bit of no rain and we are out there working on it.

Wondering how many records we have actually broken this weather year? It certainly has been eventful!

Bill Reiswig said...

How warm is the ocean that our weather is coming from? Is it warmer than usual?

joanna said...

I'm north of Bellingham, near Everson, and we got 1.30" today. My weather progran said we got a record .571" in one hour today, and I've been running stats for 6 years in this location.

Firehose rain, and this isn't even hooked up to a pineapple express!

John Marshall said...

Olympic Mountain rain shadow has really been doing its thing in Sequim... only a few sprinkles today and nothing yesterday at our house.

Weather station in the neighborhood claims 0.04" for the last day. Cloudy though. We're at 1200 feet and have been in the clouds most of the last two days.

Michael said...

Cliff, I'm on the Normandy Park/Des Moines border in the lower small pink slot on the estimated rainfall map.

I received 2.52" in 48 hours ending 6pm September 19th!

Also had a Thunderstorm roll past this afternoon just south of Des Moines.

windlover said...

Cliff ~ I found this article about a severely strong La Nina... Not sure how accurate their sources are....here's the link...wondering what your take on this is?

http://www.zerohedge.com/article/extreme-la-nina

Rob Jellinghaus said...

Cliff, what do you think this very early ground saturation might portend for the Green River valley area? There was a lot of worry last year about flooding down there, but this year seems likely to be significantly wetter -- should people be stockpiling sandbags?

windlover said...

Cliff ~ I know you already wrote a great article on the current La Nina and the upcoming winter. I sent you a link yesterday on someone saying it would be an "extreme" La Nina as to where everyone else is saying moderate to strong. This link is some other guys "forcast" for the upcoming winter. Sounds pretty treacherous... but I trust you more! I don't know who this guy is or where he gets his information from, but like yesterday, I was just wondering what your take on his "forcasts" are....Thanks! http://snowday.community.officelive.com/default.aspx

Don said...

I spent a soggy Friday night camping at Sequim Bay State Park. So much for rain shadows. Was the geometry wrong or did the storm just overwhelm that effect?

Don said...

We wrote on the 12th about a potential rain shadow protecting a wedding we were having at Lake Crescent, N of Mt Olympus. And, apparently the fabled rain shadow really works - with a south to north flow Mt Olympus protected us at the Olympic Institute/L Crescent. There was only about 0.2 inches during the weekend. The wedding even had some sun - while you in Seattle were drowning. The rain shadow must be real!

Don said...

Don #2 of the wedding suggests the other Don who was camping at Sequim was too far east to get the full benefit of the rain shadow. This cutoff also appears to agree with the chart in Cliff's writeup.

windlover said...

Ahhh... The first truly "breezy" day of fall! I love it! Cloudy, light rain blowing against the windows...an occasional gust of 30....Hope this is just a sign of the fall/winter to come! I love stormy weather! Now the only thing missing is for it to be cool enough to fire up the wood stove so I can sit snuggled on the couch reading a good book and sipping a cup of tea.....I can't wait!