How many tornadoes does the northwest see on average?

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MatthewCarman

2305 2 E BOARDMAN MORROW OR 4584 11966 POSSIBLE TORNADO WITNESSED BY TRAVELER. FUNNEL CAME HALF WAY TO THE GROUND WITH DEBRIS. TRACTOR TRAILER BLOWN OFF I-84. (PDT)

2314 6 NW HERMISTON UMATILLA OR 4589 11937 POSSIBLE TORNADO AT THE UMATILLA DEPOT. DAMAGE TO BUILDINGS AND TREES DOWN. CAPTURED ON VIDEO BY SECURITY CAMERAS. POSSIBLE TORNADO MAY HAVE OCCURRED IN BOTH MORROW AND (PDT)

0212 2 E BOARDMAN MORROW OR 4584 11966 POSSIBLE TORNADO WITNESSED BY TRAVELER. FUNNEL CAME HALF WAY TO THE GROUND WITH DEBRIS. TRACTOR TRAILER BLOWN OFF I-84. (PDT)

The last report seems to be the same as the first?


After reading yesterday's reports of twisters in Oregan I was wondering how many tornadoes on average does the northwest see? Also was yesterdays possible tornado outbreak unusual or does the northwest see a few good tornado outbreaks every year?

MOD: If I broke any rules posting the reports plz let me know and I will fix it.
 
1) Change your title (northwest, not northeast)

2) Where was there a tornado outbreak yesterday?
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I think he's using "tornado outbreak" in location-relative terms. For example, 5 tornadoes in MI could be considered an outbreak, whereas 5 tornadoes in Oklahoma wouldn't be too big of a deal.

Is there a set number for tornadoes in order to be considered an "outbreak"? Would it simply be the numbers that satisfy a high risk outlook (i.e. X amount over Y area)?

Just a thought.
 
Is there a set number for tornadoes in order to be considered an "outbreak"? Would it simply be the numbers that satisfy a high risk outlook (i.e. X amount over Y area)?

Just a thought.
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See Edwards, R., R.L. Thompson, K.C. Crosbie, J.A. Hart, and C. A. Doswell III, 2004: Proposals for Modernizing the Definitions of Tornado and Severe Thunderstorm Outbreaks. Preprints, 22nd Conf. Severe Local Storms, Hyannis MA.

It is recognized that the most significant severe “outbreakâ€￾ days of a given year do
not necessarily correspond to the greatest daily report totals.

For those reasons we have proposed modernized methods for assessing and defining tornado and
severe thunderstorm outbreaks. These have quantitative bases but empirical thresholds –
realizing that some element of arbitrariness in the process is unavoidable at this juncture. Though the
O-index (SO-index and KDE analyses) may yield useful means of comparing tornadic (nontornadic)
outbreak days, it must be noted that sampling time, spatial domain and weighting choices remain
subjective selections in the process. As such, we recognize that defining and categorizing outbreaks is
a fluid endeavor over time, as severe weather reporting practices and other relevant factors evolve.
Therefore our intent is not to define an outbreak in perpetuity, but instead, to represent the current state
and to improve the process for those who may make future refinements once our approach become
antiquated.[/b]
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I suppose I will actually address the question at hand instead of nitpicking the post. Between 1950 and 2005, Oregon had a reported 88 tornadoes, with the most recent multiple tornado day being in 2001, when two F0's touched down. Washington has had 94 in the same span, and the most recorded in a single day was four F1's on July 21, 1997. Idaho has had 171 over that time period, with multiple 4-tornado days, the most recent being August 3, 2000. The last violent tornado (greater than F2) occured on April 5, 1972 and only five F3's have occured in the entire 55 year period of record. For comparison, Oklahoma has had 3235 tornadoes over the same time period, 91 in Oklahoma County alone.

Source: NCDC Storm Data
http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dll?wwevent~storms
 
Somewhere I've heard Washington averages 2 tornadoes/year and Oregon about the same. During NWS Severe Weather Week in the Pacific NW a couple of weeks ago, NWS Spokane said WA/OR/ID average 6 tornadoes/year and July and August are the most common months for them to occur. Most are rated between F0 and F2.
http://www.wrh.noaa.gov/pqr/seasonal/may9.php

Last year there were two in WA in April, within 50 miles of where I live and within a week of each other. Both were reportedly cold-core funnels. It seems most of the tornadoes I've heard about around here over the past few years were cold-core; I guess those aren't too uncommon for the area.
 
thanks for the reply and yes I know 2-3 tornadoes are not realy an outbreak but you know what I mean.
 
I live in Oregon, and tornadoes are a rare occurence. Of the tornados that do occur, they are most likely not a product of traditional tornado genesis factors but rather due to low level wind shear. Typically, funnels do not make it to the surface. Thunderstorms can produce various cloud features that untrained eyes can mistake for possible funnel clouds. So typically, the local weather service may get a report or 2 during the year, but more often than not, it's not a genuine funnel cloud.

However, last night we got a good light show. :D Thunderstorms were developing an moving through my area beginning in the afternoon through about 8:00 or so.
 
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