Surface map for October 30, 2002 (UNISYS)
A very cold air mass from interior Canada dropped into the northern U.S. on October 29. Most of the time the Northwest avoids such events because of the sheltering effects of the Rockies and other mountain ranges, but in this case the air flow was strong enough (and the jet stream far enough south) to allow the cold air to reach all the way to the coast. Numerous low temperature records were set.
The images below show the surface map for 1700 UTC (9 a.m. PST) on October 30, and the jet stream analysis for the same day at 1200 UTC (4 a.m.). In general, arctic air will be in the areas north of the jet stream (the zone of highest winds), but will sometimes slip south of the jet. The wide dark blue line on the surface analysis is the cold front (leading edge of the cold air); at the time of this map it had reached northern Texas. This type of event is usually called a "Blue Norther" in the Midwest. By October 31, the cold front had reached the Gulf of Mexico.
According to Dennis Hull of the National Weather Service in Portland, Seneca reported a low of -11 on October 31. If it stands up (NWS is going to visit the site and check the instrument), this will be a new all-time record for October for Oregon.
STATION THIS YEAR PREVIOUS RECORD
OREGON HEPPNER 10 (TIED) 10 (1935) JOSEPH 16 (TIED) 16 (1998) MADRAS 2 N 11 (TIED) 11 (1991) TIED ALL TIME OCT LOW MEACHAM 13 17 (1972) MITCHELL 2 E 8 12 (1991) MONUMENT 10 13 (1971) ALL TIME OCT LOW MEDFORD 24 (TIED) 24 (1959) KLAMATH FALLS 15 (TIED) 15 (1994) ASTORIA 29 (TIED) 29 (1972) SALEM 22 25 (1970) EUGENE 23 27 (1991) WASHINGTON DALLESPORT AIRPORT 18 23 (1991) ALL TIME OCT LOW DAYTON 1 WSW 15 16 (1935) ELLENSBURG AIRPORT 9 20 (1946) YAKIMA AIRPORT 10 16 (1991) ALL TIME OCT LOW WALLA WALLA AIRPORT 20 24 (1991) WHITMAN MISSION 17 20 (1991)
Record Daily Low Maximum Temperatures for October 30:
STATION THIS YEAR PREVIOUS RECORD FOR THIS DAY
OREGON MEACHAM 21 30 (1971) REDMOND 31 36 (1991) JOHN DAY(CITY) 30 34 (1991) LA GRANDE(CITY) 27 33 (1991) MITCHELL 29 31 (1991) PENDLETON(CITY) 35 38 (1991) WASHINGTON WALLA WALLA 32 39 (1991) KENNEWICK 38 42 (1971) WHITMAN MISSION 36 38 (1991)
STATION THIS YEAR PREVIOUS RECORD
OREGON ASTORIA 29 30 (1995) SALEM 20 24 (1995) ALL TIME OCT LOW EUGENE 17 23 (1995) ALL TIME OCT LOW HILLSBORO 20 25 (1961) MEACHAM -8 18 (1972) ALL TIME OCT LOW PENDLETON AIRPORT 14 15 (1935) REDMOND -3 11 (1995) ALL TIME OCT LOW BEND(CITY) 0 6 (1991) ALL TIME OCT LOW HERMISTON 2NW 10 16 (1935) JOHN DAY (CITY) 4 10 (1991) ALL TIME OCT LOW LA GRANDE(CITY) 11 19 (1978) ALL TIME OCT LOW LONG CREEK -1 17 (1995) ALL TIME OCT LOW MADRAS 7 17 (1991) ALL TIME OCT LOW MONUMENT 2 3 15 (1995) ALL TIME OCT LOW MORO 7 16 (1935) ALL TIME OCT LOW MITCHELL 6 12 (1991) ALL TIME OCT LOW PENDLETON(CITY) 14 18 (1991) ALL TIME OCT LOW PENDLETON(ES) 9 15 (1978) ALL TIME OCT LOW PRINEVILLE 4 11 (1978) ALL TIME OCT LOW UNION ES 7 14 (1935) ALL TIME OCT LOW ROSEBURG 21 32 (1991) ALL TIME OCT LOW GRANTS PASS 19 24 (1917) ALL TIME OCT LOW ASHLAND 13 25 (1991) ALL TIME OCT LOW KLAMATH FALLS 8 19 (1984) ALL TIME OCT LOW WASHINGTON DALLESPORT AIRPORT 15 20 (1995) ALL TIME OCT LOW YAKIMA 4 16 (1995) ALL TIME OCT LOW WALLA WALLA 15 25 (1951) ALL TIME OCT LOW BICKLETON 8 12 (1935) ALL TIME OCT LOW KENNEWICK 18 22 (1951) SUNNYSIDE 12 19 (1995) ALL TIME OCT LOW WHITMAN MISSION 8 19 (1978) TIED ALL TIME OCT LOW
STATION THIS YEAR PREVIOUS RECORD
OREGON EUGENE 16 23 (1995) MEACHAM -2 15 (1951) REDMOND 0 8 (1995) HERMISTON 2NW 10 15 (1951) JOHN DAY(CITY) 8 13 (1995) LA GRANDE(CITY) 8 20 (1989) LONG CREEK 7 11 (1995) MADRAS 10 15 (1995) MONUMENT 2 4 11 (1995) MORO 8 15 (1995) MITCHELL 8 21 (1978) PENDLETON(CITY) 14 15 (1995) PENDLETON(ES) 9 14 (1995) PRINEVILLE 2 8 (1995) SENECA -9 -2 (1949) UNION ES 8 15 (1995) ROSEBURG 20 32 (1978) GRANTS PASS 20 21 (1893) ASHLAND 18 23 (1990) KLAMATH FALLS 10 19 (1968) LAKEVIEW (TIE) 19 19 (1989 AND 2002) WASHINGTON DALLESPORT AIRPORT 15 20 (1995) YAKIMA 6 13 (1935) WALLA WALLA AIRPORT 17 20 (1951) DAYTON(CITY) 13 13 (1935) KENNEWICK 17 19 (1951) SUNNYSIDE 12 20 (1995) WHITMAN MISSION 8 19 (1995)
STATION THIS YEAR PREVIOUS RECORD
OREGON PORTLAND 27 29 (1973) EUGENE 17 24 (1995) HILLSBORO 16 26 (1995) ASHLAND 18 23 (1990) ROSEBURG 23 33 (1993) KLAMATH FALLS 4 16 (1971) LAKEVIEW -2 11 (1935) MEACHAM 4 19 (1973) REDMOND 3 10 (1995) JOHN DAY(CITY) 10 12 (1995) PENDLETON(ES) 12 13 (1995) WASHINGTON DALLESPORT AIRPORT 14 18 (1995) YAKIMA 4 12 (1995) WALLA WALLA AIRPORT 19 24 (1951) KENNEWICK 18 20 (1951) WHITMAN MISSION 9 18 (1995)
STATION THIS YEAR PREVIOUS RECORD
OREGON PORTLAND 27 29 (1995) TILLAMOOK 21 24 (1995) HILLSBORO 22 25 (1973) ASTORIA 29 29 (1995) MCMINNVILLE 25 25 (1953) EUGENE 21 21 (1995) ROSEBURG 29 33 (1993) KLAMATH FALLS 14 14 (1995) MEACHAM 14 17 (1973) REDMOND 3 9 (1995) MITCHELL 19 19 (1957) PENDLETON(ES) 13 13 (1995) WASHINGTON DALLESPORT AIRPORT 16 19 (1995) YAKIMA 7 9 (1935) WALLA WALLA AIRPORT 20 25 (1957) KENNEWICK 20 23 (1995) WHITMAN MISSION 11 17 (1995) SUNNYSIDE 14 18 (1995)
George Taylor, State Climatologist