Major Pacific Northwest winter storm poised to slam Eastern U.S. this weekend

By: Dr. Jeff Masters , 2:11 PM GMT on December 08, 2010

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A major winter storm powered ashore today in the Pacific Northwest, bringing heavy rain and snow to the Olympic Mountains. This storm dumped four inches of rain over the Olympics, bringing the Skokomish River to flood stage. Record warm temperatures ahead of the storm have surged northwards across the Pacific Northwest, with Seattle, Washington hitting a record high of 55°F yesterday. Snowfall amounts approaching 2 feet are expected in the Olympic Mountains from the storm, with 1 - 3 feet likely in the Cascade Mountains. This is typical sort of storm one expects to see during a La Niña winter.


Figure 1. Radar-estimated precipitation from the Seattle radar for the period Dec 7 - Dec 8. Precipitation amounts in excess of 4 inches have occurred over the Olympic Mountains. Mountains surrounding Seattle block the radar beam, leading to the streaky nature of the image.

As the storm tracks eastwards over the Central U.S. later this week, it will intensify and pull in a large amount of cold, Canadian air. The latest set of computer model runs have come into much better agreement on the track of the storm, and a band of heavy snow of 6 - 10 inches is likely to set up over Central Illinois on Saturday afternoon. The storm will move rapidly eastwards, with the heaviest snow likely to impact northern Indiana, northern Ohio, and southern Ontario on Sunday. The biggest cold blast of the season thus far will roar in behind the storm, causing widespread blowing and drifting of the snow, plus new heavy Lake-effect snows in the lee of the Great Lakes. Low temperatures approaching -20°F are likely in northern Minnesota Saturday and Sunday night after the storm passes. By Tuesday morning, much of the eastern half of the nation will shiver through one the coldest mornings on record for the first half of December, with below freezing temperatures expected to penetrate all the way into South Florida. Record lows were set across much of Southeast U.S. this morning, with 39°F at Fort Lauderdale, 16°F in Columbia SC, and 9°F in Lychburg, VA. Temperatures much colder than this are likely on Tuesday morning across the region.


Figure 2. Forecast surface temperature for 7am EST on Tuesday, December 14, as predicted by this morning's 1am EST run of the GFS model. The heavy red line running along the coast of Florida is the 0°C freezing line, and temperatures below freezing are expected across nearly all of the Southeast U.S.

I'll have a new post on Thursday, when I'll discuss the CSU and TSR forecasts for the 2011 hurricane season. The TSR forecast was released Monday, and the CSU forecast is due out later today.

Jeff Masters

LAKE EFFECT SNOW SQUALL (charlesimages)
An image from the Lake Effect Snow Chase that Matt and I went on. CLICK HERE for the entire chase account detailed with videos and photos!
LAKE EFFECT SNOW SQUALL
To much snow!!!

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Quoting DoverWxwatchter:
I hope the Florida cold wave for next week does back off from some of the model predictions.  Citrus farmers have a hard time as it is.


Good evening, Dover. Agreed.
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Quoting tornadodude:


how's the weather?


It never got to our predicted low, yesterday or today. I think the land mass this time of year moderates the air mass, more than some forecasters think. It happens pretty much every year.
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I hope the Florida cold wave for next week does back off from some of the model predictions.  Citrus farmers have a hard time as it is.
Member Since: October 30, 2010 Posts: 10 Comments: 707
Quoting tornadodude:
evening everybody


evening Tornadodude.. its 34 and feel like 27 and dropping in the panhandle of FL.. How u doing??
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Sorry Doug, 53.8 here.
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Quoting pottery:

Well, in the absence of a relevant answer, I will have to surmise that it is either a 4-footed animal, with a spare.
Or perhaps 2 -and- a- half, 2-footed animals. In which case, what happened to the missing half?


Sorry for the delay my good man, I was off looking through my "My Photos" section for the photo of the big kid playing in the snow from Feb of this year here in Macon. The answer to your question is simple. My two grandchildren were too small to build a snowman, so we just built snow feet. We got to five when grandma called us inside for hot chocolate and cookies. Well, what could I do? We went inside of course. :)
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Quoting PSLFLCaneVet:


Good evening.


how's the weather?
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Good eve and Goodbye for me... I'm off to work.!
Member Since: July 25, 2006 Posts: 0 Comments: 645
Quoting tornadodude:
evening everybody


Good evening.
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Member Since: July 25, 2006 Posts: 0 Comments: 645
evening everybody
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting pottery:

Well, in the absence of a relevant answer, I will have to surmise that it is either a 4-footed animal, with a spare.
Or perhaps 2 -and- a- half, 2-footed animals. In which case, what happened to the missing half?


Good evening, Kind Sir.

Did you not notice the imperious sign reading: "No humor posts"?

(chuckling)
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Quoting pottery:

I notice that you have all 5 feet trained to walk into the tractor-bucket too!
Well Done!
But, I have to ask, what kind of animal up there, has 5 feet?
And, did you have to kill it ?

Well, in the absence of a relevant answer, I will have to surmise that it is either a 4-footed animal, with a spare.
Or perhaps 2 -and- a- half, 2-footed animals. In which case, what happened to the missing half?
Member Since: October 24, 2005 Posts: 0 Comments: 24784

Area forecast discussion
National Weather Service Jackson MS
312 PM CST Wednesday Dec 8 2010


Discussion...focus of this forecast will be on the cold temperatures
tonight...then shift to the weekend when a powerful storm will
develop across the east half of the Continental U.S. And bring winds/rain and
more cold conditions to our region for next week.


Our upper low is exiting the County Warning Area this afternoon and clouds are
dissipating in the wake of the system as subsidence develops. There
is a pesky area of low stratus that is stuck under some sort of
inversion over NE la and the western portion of the County Warning Area. This cloud
deck could play havoc with temperatures overnight if it persists longer
than expected. I'm not sure how it will evolve as model guidance does
not know it exists. My plan is to have it linger into early evening
and dissipate as the subsident flow continues to work on it. This
will result in all of the County Warning Area seeing clear skies overnight which
will result in optimal rad cooling conditions as the surface high
settles over the region. Look for a very cold night with lower 20s
area wide and a few teens possible in the typical cold spots and
outlying areas. A few records may be in jeopardy as temperatures bottom
out. Here is a list of the potential records that may fall: (tvr
24)(gwo 20)(hbg 20).


Look for moderating conditions Thursday into Friday as the surface high shifts
east and return flow develops. Conditions will still remain below
normals on Thursday and Thursday night...but just not as cold as recent days.
Better return flow develops on Friday and the resulting low level
moisture advection will offer a challenging temperature forecast. The GFS shows
warmer low level readings pushing north. However...as this
occurs...low clouds develop and keeps highs from reaching their
potential. The NAM/Euro also indicate low clouds...but mix the
boundary layer better and warm things up several more degrees. Due
to the warm air advection regime...will follow the consensus and use a blend of the
GFS/NAM...which is more in line with the Euro and the previous forecast.


In response to the developing cyclone and deepening upper
trough...warm air advection will increase quite a bit Friday night and offer the
chance of some showers later in the period. Temperatures will also be
tricky as lows will likely be met in the evening or around midnight
before warmer conditions develop toward sunrise as increasing
southerly flow pushes more low level moisture into the County Warning Area.


The main action and forecast impacts will come Sat afternoon into
Sunday. The cyclone that will develop late Sat into Monday will be
quite the system and will likely make headlines as a major storm for
a large portion of the eastern United States. Initially...this
developing system will bring strong southerly winds to our area for
Sat afternoon ahead of the deepening surface low and strong cold front.
Due to the intense dynamics of the system and increasing wind
fields...the risk of strong and severe storms remains a possibility.
The limiting factor will be instability and the details on this will
hopefully become more clear in the next few days. The strong cold
front looks to enter the northwest County Warning Area sometime from late afternoon into
early evening then quickly shift across the County Warning Area overnight. Much
colder conditions will follow this front along with increasing northwest
surface winds as intense pressure rises occur. Conditions sun will be
quite raw with windy conditions and strong cold air advection occurring. Temperatures may
struggle to reach the 40s for some locations and likely hold steady
or fall during the day.


Much colder conditions are expected for Monday into Tuesday as the core of
the Arctic air slides just to the east of the region. Even with
that...we will see enough of this cold air to experience lows in the
lower 20s and highs from the 30s to lower 40s. The potential exists
for even colder readings which may result in hard freeze conditions
for Mon-Tue. The severe weather potential statement will continue to mention these various hazards
for the Sat-Tuesday periods. /Cme/
Member Since: July 3, 2005 Posts: 427 Comments: 129411
Quoting RTLSNK:


I am not sure why Orca is always so worried about snow in Macon, Georgia. I love snow! And I am always prepared for any weather event. Why, with my equipment, I could even clear up 5 feet of snow. :)

I notice that you have all 5 feet trained to walk into the tractor-bucket too!
Well Done!
But, I have to ask, what kind of animal up there, has 5 feet?
And, did you have to kill it ?
Member Since: October 24, 2005 Posts: 0 Comments: 24784
New Haven, Connecticut at 9:17pm
26.3 °F Clear Tonight
Mostly clear. Lows around 18. West winds 10 to 15 mph. cold night here!!!
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Quoting pottery:

You burn the furniture ???


I am not sure why Orca is always so worried about snow in Macon, Georgia. I love snow! And I am always prepared for any weather event. Why, with my equipment, I could even clear up 5 feet of snow. :)
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Dang, almost 7 months before the next Atlantic season, it's nearly the Holiday's, and no humor. Sad.
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snow picture!!
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finally having the time to come back to weather underground hope to be able to stay for awhile it looks like the east and north east is about to get slammed by a snow storm looking like a repeat of last year
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Quoting DDR:


Thanks for that info,i had no idea
That's La nina,rain making monster :S

It's on the BBC website...
Member Since: October 24, 2005 Posts: 0 Comments: 24784
Quoting KerryInNOLA:
Dr Gray's 2011 predictions, 17-9-5, normal year, 11-6-2.


See no reason why it won't be an above average year. El Nino is unlikely.
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Dr Gray's 2011 predictions, 17-9-5, normal year, 11-6-2.
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225. DDR
Quoting pottery:

I am good with that!

In the meantime, the Panama Canal is closed.
Due to heavy rains that have overfilled some of the lakes that make-up the Canal. The Panamanians are dumping water from some of the lakes, in an effort to re-open the Canal.
This will create havoc for Pacific/Atlantic shipping, if the rains dont ease up there.

Quoting pottery:

I am good with that!

In the meantime, the Panama Canal is closed.
Due to heavy rains that have overfilled some of the lakes that make-up the Canal. The Panamanians are dumping water from some of the lakes, in an effort to re-open the Canal.
This will create havoc for Pacific/Atlantic shipping, if the rains dont ease up there.

Thanks for that info,i had no idea
That's La nina,rain making monster :S
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Lord, no GW. There were some good tunes. Here's hoping you like it.

Cheers!



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Quoting TampaFLUSA:

Are the models coming in warmer in the SE?


That might be a possibility. Both NOAA and Accuweather haven't changed their original forecast even after the talks of a major cold spell.
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Quoting DDR:
Hi pottery
My feeling is that these rains will continued well into next year.
When the poui trees start to blossom in November,you know the next wet season will start early,strange...

I am good with that!

In the meantime, the Panama Canal is closed.
Due to heavy rains that have overfilled some of the lakes that make-up the Canal. The Panamanians are dumping water from some of the lakes, in an effort to re-open the Canal.
This will create havoc for Pacific/Atlantic shipping, if the rains dont ease up there.
Member Since: October 24, 2005 Posts: 0 Comments: 24784
By looking at the models.. I believe much of December will be cold for most of us in the US.. including the south east.. But not as cold as projected to be for monday and into tuesday morning.. But u never know, changes from time to time..

Also the NAM has more rain for the south and southeast and saying the cold blast won't catch up to the rain.. B/c most of the precipitation would be near or ahead of the front that is moving through.. But I believe these models will flip flop back n forth until they get better agreement near friday.. JMO
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Quoting doorman79:


It is if you don't like it. And by the way, no one here is talking about GW. So either post a good Christmas song or S!@#w off. :)
I could report you to Admin for rude behavior but I am in the holiday spirit. And your wrong, that's all they were talking about yesterday (GW).
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Quoting GeoffreyWPB:
For West Palm Beach...not as cold as forecasted earlier today:


Are the models coming in warmer in the SE?
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218. DDR
Hi pottery
My feeling is that these rains will continued well into next year.
When the poui trees start to blossom in November,you know the next wet season will start early,strange...
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it keeps going as a matter of fact there is a new high rise going up just up the street they finihed with all the glass two weeks ago so its enclosed now and most companies use portabil heat like propane to heat construction sites
Member Since: July 15, 2006 Posts: 176 Comments: 55517
Quoting KEEPEROFTHEGATE:
i got 6 gas fire boilers fired up water temp going out is at 180f with a rtn coming back of 110 3 boilers for east side of high rise 3 boilers for west side of the high rise psi is at 30 also have 2 additional boilers for domestic hot water in total 8 boilers in the building internal air temp is kept at 76f inside at all times it cost about $20,000 per month to heat the building in the dead of winter


Do ya'll have people building houses, buildings this time of year. Or does construction kinda stop during the cold snaps?
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Quoting doorman79:


How do you keep the inside of a house at 70f in that kind of cold?
i got 6 gas fire boilers fired up water temp going out is at 180f with a rtn coming back of 110 3 boilers for east side of high rise 3 boilers for west side of the high rise psi is at 30 also have 2 additional boilers for domestic hot water in total 8 boilers in the building internal air temp is kept at 76f inside at all times it cost about $20,000 per month to heat the building in the dead of winter
Member Since: July 15, 2006 Posts: 176 Comments: 55517
Quoting pottery:

You burn the furniture ???


Umm! Smores. ;)
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Quoting KerryInNOLA:
This weather is not typical for early December. But it is also not unusual. It is really not a big deal.


It is if you don't like it. And by the way, no one here is talking about GW. So either post a good Christmas song or S!@#w off. :)
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Quoting doorman79:


How do you keep the inside of a house at 70f in that kind of cold?

You burn the furniture ???
Member Since: October 24, 2005 Posts: 0 Comments: 24784
Quoting pottery:

Nowhere to store it.
Working on Disposing of it, in the Approved Manner.
"cheers"


Get a tire intertube with an icechest/box tied on it. There you go!
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This weather is not typical for early December. But it is also not unusual. It is really not a big deal.
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Quoting KEEPEROFTHEGATE:

17f now going down to a low of 8f or 9f with chills of -5 or -10f depending on winds


How do you keep the inside of a house at 70f in that kind of cold?
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Quoting doorman79:


Save the Wine!

Nowhere to store it.
Working on Disposing of it, in the Approved Manner.
"cheers"
Member Since: October 24, 2005 Posts: 0 Comments: 24784
Quoting doorman79:


Man, thats cold! We complaining about our lows in the high 20s.

17f now going down to a low of 8f or 9f with chills of -5 or -10f depending on winds
Member Since: July 15, 2006 Posts: 176 Comments: 55517
Quoting pottery:


Yeah, it's been heavy....
I am not sure when these warnings/comments were issued, but over the past 4 hours the weather has cleared a bit (stars are out!!) and unless something changes soon, tomorrow should be a less wet day.

Rivers are overflowing in several areas, and others are at max. right now.
Only minor landslips reported, but if this does not clear out of here soon, we will be in some trouble....


Save the Wine!
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Quoting KEEPEROFTHEGATE:


Toronto Pearson Int'l Airport
Date: 7:00 PM EST Wednesday 8 December 2010
Condition: Clear
Pressure: 30.09 inches
Tendency: rising
Visibility: 15 miles
Air Quality Health Index: 3

Temperature: 17.8°F
Dewpoint: 7.2°F
Humidity: 63 %
Wind: WNW 16 mph
Wind Chill: 3


Man, thats cold! We complaining about our lows in the high 20s.
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Quoting DDR:
None stop rain here in Trinidad
4 inches here since yesterday
Many places are under water
When will this end???

The Trinidad and Tobago Meteorological Services is
issuing a riverine flood alert for Trinidad having
regard to the occurrence of persistent rainfall
activity over the last 18 %u2013 24 hours.
This latest rainfall event began favouring the
northeast sector of Trinidad and has already
emptied considerable precipitation to engineer
riverine floods but isolated to this region.
The center is now shifting with maximum
concentrations eclipsing central Trinidad, parts
of North Trinidad and areas of South Trinidad.
These locations are already estimated to have
received between 50 %u2013 60 millimeters of
rainfall.



The atmospheric dynamics is showing a tendency for
the northern fringes of Inter-Tropical Convergence
Zone (ITCZ) to merge with this quasi-stationary
shear line currently affecting both Trinidad and
Tobago. This possible development together with
an upper level trough and highly supportive upper
level flows may broaden the area of instability to
unleash a new burst of energy capable of producing
significant rainfall overnight into tomorrow.
Conservative estimates are for between 75-100
millimeters of rainfall accumulation.


Yeah, it's been heavy....
I am not sure when these warnings/comments were issued, but over the past 4 hours the weather has cleared a bit (stars are out!!) and unless something changes soon, tomorrow should be a less wet day.

Rivers are overflowing in several areas, and others are at max. right now.
Only minor landslips reported, but if this does not clear out of here soon, we will be in some trouble....
Member Since: October 24, 2005 Posts: 0 Comments: 24784
Evening All!

No precip of any kind today. Anyone here get flurries around the gulf coast?

What up Orca and KOTG!
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Quoting jasoniscoolman2010xo:


Toronto Pearson Int'l Airport
Date: 7:00 PM EST Wednesday 8 December 2010
Condition: Clear
Pressure: 30.09 inches
Tendency: rising
Visibility: 15 miles
Air Quality Health Index: 3

Temperature: 17.8°F
Dewpoint: 7.2°F
Humidity: 63 %
Wind: WNW 16 mph
Wind Chill: 3
Member Since: July 15, 2006 Posts: 176 Comments: 55517
COLD WEATHER!!! LOOK AT THE WEATHER MAP!!
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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