Weather Discussion
January 31, 2012
Cliff Mass
Did we break the ALL TIME record low
temperature for the U.S. this week?
• The record has been -80F (actually -79.8F) on
January 23, 1971 at Prospect Creek Camp
Alaska.
• Located along the Alaska Pipeline, about 20
miles north of the Arctic Circle.
• Perfect terrain situation for cold temperature
records.
Well inland,
and
protected
from
marine
influences
by large
terrain
barriers
High
Valley
in a
Plateau
Region
Cold air sinking off Mts. Can pool in valley
New Record?
• Jim River DOT
site (JMTA2)
near Prospect
Creek
Hit -79F for TWO hours and reports stopped! Could
it have reached the record between the hours?
Other days temps fell after 1835 UTC
Jan 28, 18 UTC
Hmmm…seems at odds with others
•
NOAK49 PAFG 302352
PNSAFG
AKZ219-222-311200PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
252 PM AKST MON JAN 30 2012
...CLARIFICATION OF TEMPERATURES FROM JIM RIVER DOT CAMP...
TEMPERATURES THIS PAST WEEKEND AT THE ALASKA DEPARTMENT OF
TRANSPORTATION JIM RIVER MAINTENANCE CAMP AT MILE 138 DALTON
HIGHWAY...STATION JMTA2...HAVE BEEN REPORTED AS LOW AS 79 BELOW.
THE TEMPERATURES ARE NOT CORRECT. THE WEATHER STATION IN USE AT
THE JIM RIVER DOT CAMP IS A PERSONAL WEATHER STATION THAT IS NOT
RATED FOR TEMPERATURE COLDER THAN 40 BELOW. THE UNREALISTICALLY
LOW TEMPERATURES ARE BELIEVED TO BE A FUNCTION OF THE BATTERY
FAILING AT VERY LOW TEMPERATURES.
THERE ARE NO OFFICIAL...NATIONAL WEATHER SERVICE STANDARD...
TEMPERATURE MEASUREMENTS AT JIM RIVER DOT CAMP.
What is the coldest temperature in the
NW and Where?
Northwest
Low
Temperature
Extremes
Washington: -48F
Oregon:
-54F
The records are
all east of the
Cascades
On December 30, 1968 both
Mazama and Winthrop, WA
dropped to -48F—the state
record.
Why there?
Winthrop and
Mazama are in a
deep valley of
the northeast
Cascades
The Cascades shield the valley from the warm air of the
Pacific
Snow promotes cooling
Lack of clouds helps radiational cooling
Cold dense air settles into the protected valley.
Wintertime low clouds in eastern Washington
The coldest
temperature in
Oregon is at Seneca,
located in a valley in
the eastern Oregon
highlands
La Nina Update
Solid for this winter
Neutral ENSO next winter
SST Departures (oC) in the Tropical Pacific During
the Last 4 Weeks
During the last 4-weeks, equatorial SSTs were more than 0.5°C below average between
155°E and 100°W and more than 1°C below average in most of the central Pacific
between 165°E and 120°W.
Recent Evolution of Equatorial Pacific SST
Departures (oC)
Time
Over the past month, below-average
SSTs have persisted across much of the
equatorial Pacific.
Longitude
Niño Region SST Departures (oC)
Recent Evolution
The latest weekly SST departures are:
Niño 4
-1.2ºC
Niño 3.4
-1.1ºC
Niño 3
-0.7ºC
Niño 1+2
-0.4ºC
Sub-Surface Temperature Departures (oC)
in the Equatorial Pacific
• During December 2011, negative subsurface
temperature anomalies (100-300m)
strengthened slightly in the eastern half of the
Pacific.
• During the recent period, the negative
anomalies have persisted across the eastern
half of the Pacific.
Time
Most recent pentad analysis
Longitude
Tropical OLR and Wind Anomalies
During the Last 30 Days
Negative OLR anomalies (enhanced convection and
precipitation, blue shading) were observed over the
Philippines, Malaysia and Indonesia. Positive OLR
anomalies (suppressed convection and precipitation,
red shading) were located over the western and central
tropical Pacific.
Low-level (850-hPa) easterly anomalies were observed
over the central and western tropical Pacific.
Consistent with La Nina Circulation
La Nina Upper Level Anomaly
Pattern (500hPa)
Atmospheric Circulation over the North Pacific & North America
During the Last 60 Days
500-hPa Height & Anoms.
925-hPa Temp. Anoms. (oC)
During December through January, an anomalous ridge persisted over the eastern North Pacific and aboveaverage heights extended into the contiguous U.S. Associated with this ridging, above-average temperatures were
evident across much of North America, except for Alaska.
La Nina Temp Composite
U.S. Temperature and Precipitation Departures During the
Last 30 and 90 Days
Last 30 Days
Last 90 Days
30-day (ending 28 Jan 2012)
temperature departures
(degree C)
90-day (ending 28 Jan
2012) temperature
departures (degree C)
Pacific Niño 3.4 SST Outlook
• The majority of models predict the continuation of La Niña (Niño-3.4 SST anomalies less than
-0.5°C) at least through the Northern Hemisphere spring (March-April-May).
Figure provided by the
International Research
Institute (IRI) for Climate
and Society (updated 17
January 2012).
SST Outlook: NCEP CFS.v1 Forecast Issued
30 January 2012
The CFS.v1 ensemble mean (black dashed line)
predicts La Niña conditions to continue into the
Northern Hemisphere spring 2012.
A Signature of Normal La Nina
Years is Enhanced Snowpack—
Particularly Late in the Season
Major Snowpack Changes over Past Two Weeks
Westerly Wind Surge in Strait
Ivar’s Mukilteo Landing Restaurant
Gets Hit
Smith Island
Smith Island
UIL-BLI jumped to 6 mb
Bipolar Smith Island
Extraordinary Ridging Ahead
ECMWF-72h
120h
168h
North
American
Ensemble
Forecast
System