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January 2010 - Possible Arctic Outbreak


jasons
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Hi all.

I'm an avid weather watcher, I have been for many years, and this is a topic I feel deserves a new thread.

There are not many times when I see an event depicted on the computer models that have me truly concerned about my garden. We see these horrific scenarios show-up all the time, only to drop off a few model runs later. It's not easy to get my feathers ruffled. To put things into perspective, since we moved to Houston in 2005 the first time I got really concerned was January of last year. And for good reason - I had a low of 19 and stayed below freezing for almost three days straight.

Onto my point: the models are showing a potentially devastating cold surge into the US next week. They have been consistent and the elements now appear to be coming together for this to verify. It's quite possible there will be a 1050+ mb high pressure moving into Montana and down into the Plains - with possibly more cold shots coming in succession. These are the same types of scenarios that resulted in the '83 and '89 and 2010 freezes.

I'm not forecasting Armageddon just yet. It's still a full week away before this gets into full swing. But I wanted to put you guys on notice now to get prepared. Both Texas and Florida could see a severe cold outbreak beginning next week. We could be talking about days below freezing in places like Dallas and a hard freeze into the RGV. It's too early to talk specifics but that's the type of severity we could be looking at. Keep a close watch on the weather over the next several days as this event unfolds.

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It says 2010 in the title-just to clarify, do you mean 2011? I would prefer you meant the former, but unfortunately, I suspect you mean the latter? I am so over the cold right now-we just had the coldest Dec on record. As well as 9" of snow just last week

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Sorry, I meant 2011. It's still early in the year and I'm still used to 2010. If an Admin can edit the title, I would appreciate it, thanks.

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Armageddon!

It's always just around the corner.

This is going to be, from the looks, a tough winter for all of us, here in the Land O'La La, and in the Heartland, and along the East Coast.

Of course, false alarms are always better.

Let's keep our forum fun and friendly.

Any data in this post is provided 'as is' and in no event shall I be liable for any damages, including, without limitation, damages resulting from accuracy or lack thereof, insult, or lost profits or revenue, claims by third parties or for other similar costs, or any special, incidental, or consequential damages arising out of my opinion or the use of this data. The accuracy or reliability of the data is not guaranteed or warranted in any way and I disclaim liability of any kind whatsoever, including, without limitation, liability for quality, performance, merchantability and fitness for a particular purpose arising out of the use, or inability to use my data. Other terms may apply.

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The 10-day out forecast are showing some cold weather, but nothing Armageddon'ish, nor even abnormal for this time of year, but I know we have some weathermen out there. Weigh in guys, please.

In my post I sometimes express "my" opinion. Warning, it may differ from "your" opinion. If so, please do not feel insulted, just state your own if you wish. Any data in this post is provided 'as is' and in no event shall I be liable for any damages, including, without limitation, damages resulting from accuracy or lack thereof, insult, or any other damages

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The 10-day out forecast are showing some cold weather, but nothing Armageddon'ish, nor even abnormal for this time of year, but I know we have some weathermen out there. Weigh in guys, please.

Well, here is what the NWS from Shreveport had to say about it in their PM discussion today (sorry for the caps but that's how they publish them):

MEDIUM RANGE PROGS CONTINUE TO SUPPORT A LARGE 1060MB POOL OF VERY

COLD...ARCTIC AIR SPILLING DOWN OUT OF THE NORTHERN PLAINS EARLY

NEXT WEEK WITH THE LEADING EDGE OF THIS AIRMASS MOVING INTO OUR

REGION DURING THE DAY MONDAY. DETAILS CONCERNING THE LONGEVITY AND

DEGREE OF COOLING THAT WILL TAKE PLACE IS STILL IN QUESTION BUT

WITHOUT A DOUBT...THIS WILL BE SOME OF THE COLDEST AIR OF THE

WINTER SEASON. ATTM...PREFER THE GFS HANDLING OF THE SFC RIDGING

ALONG THE FRONT RANGE AND KEEPING IT THERE THROUGHOUT NEXT WEEK AS

OPPOSED TO THE ECMWF WHICH PUSHES THE ARCTIC AIR TO FAR EAST TOO

QUICKLY. THIS IS SOMETHING THAT WILL BE WATCHED IN EARNEST

THROUGHOUT THE WEEK...BUT THIS AIRMASS AND UPPER LEVEL PATTERN

DOES MIMIC SOME OF THE MORE NOTABLE MCFARLAND SIGNATURES IN THE

PAST...INCLUDING DECEMBER OF 1983 AND DECEMBER OF 1989. HAVE MADE

MENTION OF THIS IN OUR HAZARDOUS WEATHER OUTLOOK...TALKING ABOUT

THIS AIRMASS NEXT WEEK ALONG WITH MAKING PREPARATIONS.

http://forecast.weather.gov/product.php?site=NWS&issuedby=SHV&product=AFD&format=CI&version=1&glossary=1

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The 10-day out forecast are showing some cold weather, but nothing Armageddon'ish, nor even abnormal for this time of year, but I know we have some weathermen out there. Weigh in guys, please.

Well, here is what the NWS from Shreveport had to say about it in their PM discussion today (sorry for the caps but that's how they publish them):

MEDIUM RANGE PROGS CONTINUE TO SUPPORT A LARGE 1060MB POOL OF VERY

COLD...ARCTIC AIR SPILLING DOWN OUT OF THE NORTHERN PLAINS EARLY

NEXT WEEK WITH THE LEADING EDGE OF THIS AIRMASS MOVING INTO OUR

REGION DURING THE DAY MONDAY. DETAILS CONCERNING THE LONGEVITY AND

DEGREE OF COOLING THAT WILL TAKE PLACE IS STILL IN QUESTION BUT

WITHOUT A DOUBT...THIS WILL BE SOME OF THE COLDEST AIR OF THE

WINTER SEASON. ATTM...PREFER THE GFS HANDLING OF THE SFC RIDGING

ALONG THE FRONT RANGE AND KEEPING IT THERE THROUGHOUT NEXT WEEK AS

OPPOSED TO THE ECMWF WHICH PUSHES THE ARCTIC AIR TO FAR EAST TOO

QUICKLY. THIS IS SOMETHING THAT WILL BE WATCHED IN EARNEST

THROUGHOUT THE WEEK...BUT THIS AIRMASS AND UPPER LEVEL PATTERN

DOES MIMIC SOME OF THE MORE NOTABLE MCFARLAND SIGNATURES IN THE

PAST...INCLUDING DECEMBER OF 1983 AND DECEMBER OF 1989. HAVE MADE

MENTION OF THIS IN OUR HAZARDOUS WEATHER OUTLOOK...TALKING ABOUT

THIS AIRMASS NEXT WEEK ALONG WITH MAKING PREPARATIONS.

http://forecast.weat...on=1&glossary=1

Well now. This sucks.

In my post I sometimes express "my" opinion. Warning, it may differ from "your" opinion. If so, please do not feel insulted, just state your own if you wish. Any data in this post is provided 'as is' and in no event shall I be liable for any damages, including, without limitation, damages resulting from accuracy or lack thereof, insult, or any other damages

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From the Houston Chronicle:

Arctic blast set to blanket region

Houston area could soon see lows in the teens

By ERIC BERGER

HOUSTON CHRONICLE

Jan. 4, 2011, 7:21PM

Texas may feel a lot like Alaska next week.

Forecasters say a blast of Arctic air should begin filtering into the Houston region by late Monday and continue doing so for several days. It should be the city's coldest spell of this winter, by far, likely bringing a hard freeze.

"Even though it's a little too early to predict overnight lows this far out, there is some potential that temperatures could fall as low as the low-to-mid 20s over the immediate coast," said Fred Schmude, a meteorologist with ImpactWeather, a private forecasting company in Houston.

"Just inland from the coast temperatures as low as the teens and low 20s will be possible."

The coldest days and nights should come between Jan. 12 through Jan. 17. Schmude said there's a chance of light snow or freezing rain during the cool down.

The coldest night of winter so far this year, Dec. 27, saw temperatures fall to just 29 degrees.

If temperatures fall into the low 20s the hard freeze could threaten more than plants and pets. Exposed pipes could be at risk as well.

Last January, when overnight lows dipped to 20 degrees, there were sporadic incidents of burst pipes around Houston.

It's too early to say whether temperatures will get quite that cold again.

eric.berger@chron.com

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Not according to the CPC or Joe Bastardi at Accuweather. The long range forecast (through January 17th) from the CPC has the Florida peninsula with normal temps. It does show high chances of below normal temps in Texas. The CPC pegged the Florida outbreak last week well in advance. The Arctic Oscilation will be negative but only barely. If it were really going to barrell us over here in Florida, we'd already have the models suggesting as much.

From the CPC this afternoon:

TODAYS ENSEMBLE MEAN SOLUTIONS ARE IN GOOD AGREEMENT ON THE 500-HPA HEIGHT

PATTERN FOR WEEK 2, AND THE FORECAST PATTERN IS VERY SIMILAR TO THE EARLIER

PERIOD. THE NEGATIVE AO PATTERN IS FORECAST TO PERSIST THROUGH THE WEEK 2

PERIOD. THE 6Z GFS OPERATIONAL SOLUTION DEPICTS THE US TROUGH OVER THE

WEST-CENTRAL STATES, SIMILAR TO THE EARLIER PERIOD, WHILE THE 0Z GFS FORECASTS

IT TO BE OVER THE EASTERN US. SINCE THE GFS OPERATIONAL SOLUTIONS SHOW SOME

DIFFERENCES OVER THE CONUS, THE OFFICIAL FORECAST IS BASED PRIMARILY ON THE

VARIOUS ENSEMBLES. GREATER ODDS FOR NEAR AVERAGE TEMPERATURE ARE FORECAST

ALONG THE GULF COAST AND FOR FLORIDA SINCE HEIGHTS ARE FORECAST TO BE NEAR

AVERAGE IN THAT REGION. ENHANCED ODDS FOR ABOVE MEDIAN PRECIPITATION ARE

FORECAST FOR THE OHIO AND TENNESSEE VALLEYS, DOWNSTREAM OF THE TROUGH OVER THE

CENTRAL US.

I'm also a weather buff and spend way too much time looking at the European and GFS weather models.

A quote from one of the Accuweather meteorologists:

"An extremely cold air mass is coming down from the Rockies and is currently on a path moving to the east," Mohler said. "On the current track, it should stay north of Florida."

Tampa, Interbay Peninsula, Florida, USA

subtropical USDA Zone 10A

Bokeelia, Pine Island, Florida, USA

subtropical USDA Zone 10B

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Not according to the CPC or Joe Bastardi at Accuweather. The long range forecast (through January 17th) from the CPC has the Florida peninsula with normal temps. It does show high chances of below normal temps in Texas. The CPC pegged the Florida outbreak last week well in advance. The Arctic Oscilation will be negative but only barely. If it were really going to barrell us over here in Florida, we'd already have the models suggesting as much.

From the CPC this afternoon:

TODAYS ENSEMBLE MEAN SOLUTIONS ARE IN GOOD AGREEMENT ON THE 500-HPA HEIGHT

PATTERN FOR WEEK 2, AND THE FORECAST PATTERN IS VERY SIMILAR TO THE EARLIER

PERIOD. THE NEGATIVE AO PATTERN IS FORECAST TO PERSIST THROUGH THE WEEK 2

PERIOD. THE 6Z GFS OPERATIONAL SOLUTION DEPICTS THE US TROUGH OVER THE

WEST-CENTRAL STATES, SIMILAR TO THE EARLIER PERIOD, WHILE THE 0Z GFS FORECASTS

IT TO BE OVER THE EASTERN US. SINCE THE GFS OPERATIONAL SOLUTIONS SHOW SOME

DIFFERENCES OVER THE CONUS, THE OFFICIAL FORECAST IS BASED PRIMARILY ON THE

VARIOUS ENSEMBLES. GREATER ODDS FOR NEAR AVERAGE TEMPERATURE ARE FORECAST

ALONG THE GULF COAST AND FOR FLORIDA SINCE HEIGHTS ARE FORECAST TO BE NEAR

AVERAGE IN THAT REGION. ENHANCED ODDS FOR ABOVE MEDIAN PRECIPITATION ARE

FORECAST FOR THE OHIO AND TENNESSEE VALLEYS, DOWNSTREAM OF THE TROUGH OVER THE

CENTRAL US.

I'm also a weather buff and spend way too much time looking at the European and GFS weather models.

A quote from one of the Accuweather meteorologists:

"An extremely cold air mass is coming down from the Rockies and is currently on a path moving to the east," Mohler said. "On the current track, it should stay north of Florida."

Hope you're right but as we often see in CA, the forecasts can change overnight.

Coastal San Diego, California

Z10b

Dry summer subtropical/Mediterranean

warm summer/mild winter

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Check out Accuweather meteorologist Frank Strait's video from last night.

http://www.accuweather.com/blogs/strait/story/43956/bigtime-cold-coming.asp

Tampa, Interbay Peninsula, Florida, USA

subtropical USDA Zone 10A

Bokeelia, Pine Island, Florida, USA

subtropical USDA Zone 10B

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This is from a local meteorologist here in Houston - his name is Jeff Lindner and works for the Harris County Flood Control district. He sends out a good write-up that lays it all out (at least for Texas). FWIW my concern for Florida is a bit later, after this initial surge of cold air.

Next Week:

Models have backed off on the strong arctic air event for next week in their 00Z and 06Z runs, but will not fully bite on this downplaying of the event. Models typically have a very hard time resolving these outbreaks due to their shallow nature east of the Rocky mountains and it is more surprising how much agreement they have had over the past 2-3 days on this event. With that said, all models do continue to show a favorable delivery pattern for arctic air to enter the US Saturday and reach the southern plains by Sunday. 1048mb high is progged just north of the Montana border early next week with 1040mb pressures building into WC TX by Tuesday. Note that these pressures are about 10mb lower than what we were looking at 2 days ago suggesting the intensity of the arctic high may not be as strong. Passing weekend southern plains/TX storm system should help grab the shallow arctic air mass over the central plains and sling it rapidly southward on Sunday. Will toss out the model guidance for Monday in favor of the arctic air mass pushing southward under its own density and arriving to the TX coast by Monday afternoon/evening. Typically once these air masses get moving there is little to stop them. Will need to undercut the GFS guidance from Tuesday onward by at least 10 degrees on the afternoon highs as the model is just not grasping this air mass today as in previous runs. Will go with highs in the 40’s on Tuesday under strong cold air advection and then highs in the 30’s on Wednesday as the arctic dome becomes fully entrenched. Not sure how much clearing will take place behind the front as there does look to be a period of post frontal low stratus and this will help temper the overnight lows…so low 30’s on Tuesday morning to upper 20’s on Wednesday morning. Should clouds clear out…overnight lows will be about 5-8 degrees colder.

GFS attempts to completely erode the arctic dome by Thursday and Friday of next week as it spins up low pressure in the lee of the Rockies inducing southerly flow over TX. Once in place arctic cold domes are hard to dislodge, and suspect the model is moving the cold air too quickly eastward. GFS then crashes a secondary surge down the plains next weekend arriving around the 16/17 of the month.

As mentioned before we are not looking at anything historic or record breaking from this pending event, but a prolonged period of well below normal cold with potential for hard freezes over multiple days still looks likely. It remains questionable on how intense this outbreak may be and how long it will last. Stay tuned.

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Ont thing to add: when Jeff says "will need to undercut GFS guidance by 10 degrees" -- this means it will be colder that what the models currently output.

When you go to weather.com or accuweather.com and enter your zip code for a forecast - that forecast you see beyond 48 hours is usually just the GFS model output with no human intervention or thought. So when you see that 10-day forecast with a low of 35, you're just looking at the GFS output number which is subject to very large errors in the long-term.

Edited by jasons
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Jason, thanks again for the heads up. Arctic air that travels south and then shifts east may be arctic in its initial surge south but modifies during its eastward track. If Texas gets the brunt of the cold, the air modifies over the hundreds of miles as it travels east and over the relatively warmer Gulf water. I'm not downplaying your warning but merely pointing out that this outbreak is either Florida's or Texas' but not both. If Texas gets very cold, Florida usually gets a moderated air mass. If Florida gets the brunt of the cold, Texas usually escapes unharmed.

Tampa, Interbay Peninsula, Florida, USA

subtropical USDA Zone 10A

Bokeelia, Pine Island, Florida, USA

subtropical USDA Zone 10B

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Jason, thanks again for the heads up. Arctic air that travels south and then shifts east may be arctic in its initial surge south but modifies during its eastward track. If Texas gets the brunt of the cold, the air modifies over the hundreds of miles as it travels east and over the relatively warmer Gulf water. I'm not downplaying your warning but merely pointing out that this outbreak is either Florida's or Texas' but not both. If Texas gets very cold, Florida usually gets a moderated air mass. If Florida gets the brunt of the cold, Texas usually escapes unharmed.

Usually, yes, and that is the key word. The 80's freezes (and the great freeze of 1899) got both TX and FL; there was no escaping the cold air. It all depends on the trajectory of the cold.

In this case, none of this probably even matters as the models continue to back off the cold threat for next week. The challenge for model watchers is that the GFS often sniffs out a cold outbreak, then backs off in the mid-range time frame, then brings it back in earnest just before the event takes place. There is a great debate right now if the GFS is up to its usual antics or if the Euro was right all along. It's beginning to look like the GFS was overdoing things because NW Canada has a long way to go if it's going to build that monster high that made me almost sick on Sunday night's run.

Right now, it does appear we are on track for a cold front to arrive in SE Texas on Sunday/Monday and we should still get a decent freeze out of this. How cold and how severe remains to be seen but I feel much better today than I did yesterday; I'm not expecting Armegeddon like I was fearing.

Edited by jasons
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A summary of Joe Bastardi's Accuweather blog today.

"Winter has only just begun, and many people across the country are already sick of the cold. On the heels of a record-cold December, frigid weather will continue seizing areas from coast to coast through mid- to late January.

Based on this forecast, AccuWeather.com Chief Long Range Forecaster Joe Bastardi says this month could turn out to be the coldest January for the nation as a whole since 1985.

While there has been outstanding regionalized cold in January in recent years, Bastardi points out that the U.S. has not experienced this type of coast-to-coast cold since the 1980s.

Record-smashing cold already gripped a large portion of the West the first few days of the month with snow even falling in Las Vegas Monday. Bitter arctic air has also made a return to the northern Plains, while the East and South experienced a dramatic cooldown since the weekend.

More waves of arctic air will invade the country, starting late this week and continuing through next week and beyond. The period from Jan. 10-20 is when Bastardi expects the core of the cold to be in place, with the northern Plains in the heart of it.

He says places from Chicago to Denver could have one or two days with high temperatures below zero during this time. People in New York City may be looking at one day with highs in the teens, while temperatures potentially fail to rise out of the 20s in Dallas, Texas, and Jackson, Miss., for a day or two.

Bastardi also highlights the potential for rare snow in Seattle and Portland with the upcoming weather pattern.

The cold air coming to Texas starting early next week could affect the state's citrus industry, according to Bastardi. He thinks Florida citrus, however, should be safe.

This past weekend, AccuWeather.com Expert Senior Meteorologist Alex Sosnowski started warning about the severe cold that is coming and provided more details on just how bad it will be."

Tampa, Interbay Peninsula, Florida, USA

subtropical USDA Zone 10A

Bokeelia, Pine Island, Florida, USA

subtropical USDA Zone 10B

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Joe loves the Euro; that is no secret among weather weenies. Can't say I blame him most of the time.

FWIW the latest run of the Euro flipped cold again and now at day-10 it shows the coldest air of the season centered over Calgary, poised to plunge south. The moral of the story IF that verifies: this first cold front/surge early next week is the beginning of a possible continued "step-down" (what Joe would say) with much colder air to follow.

Edited by jasons
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Latest discussion from NWS Houston:

MONDAY EVENING THE MUCH TOUTED ARCTIC COLD FRONT WILL BE DROPPING

INTO NORTH TEXAS AND BY 12Z TUESDAY WILL BE THROUGH SOUTHEAST

TEXAS. THE PATTERN DOESN`T SUPPORT THE BITTER COLD AIR THAT WAS

PROGGED TO COME SOUTH A FEW DAYS AGO. IT WILL STILL BE COLD BUT

NOT AS COLD...LOWS 29-33 WILL BE COMMON TUESDAY MORNING AND THEN

WARMING INTO THE 40S...DIPPING BACK DOWN INTO THE MID 20S NORTH

AND MID TO UPPER 30S COAST. UNFORTUNATELY THE MODELS ARE

INDICATING ANOTHER ARCTIC AIRMASS LINING UP ACROSS CANADA AND

NORTHERN HIGH PLAINS AS EARLY AS THE FOLLOWING SATURDAY (15TH).

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Not great news but better. At this point, we'll take anything we can get.

Tampa, Interbay Peninsula, Florida, USA

subtropical USDA Zone 10A

Bokeelia, Pine Island, Florida, USA

subtropical USDA Zone 10B

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Hey Ray, I hope it continues to get better but I'm not too optimistic right now. The forecasters are increasingly confident we're going to get a strong but modified Arctic front to plunge through here on Sunday and we could have several mornings in the 20's here. It will be cold but nothing historic. The focus is now on the possible front behind that one, poised to drop down the plains in the next Saturday (16th) time frame. The models are showing a decent surge of arctic air and snow well in the SE US (all the way to the MS/AL/FL Gulf Coast with this one), but we're talking so far out in model-land, anything could happen. The GFS shows it snowing in the Gulf of Mexico a few times each year only to come back to reality a few runs later. I'm not so sure it's out to lunch this time though as the Euro also supports what the GFS shows.

All in all, regardless of schematics, the rest of January looks very cold and stormy for virtually everyone east of the Rockies with a threat of severe cold later in the month.

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It looks like a chilly stretch, but nothing out of the norm for January here. The following predictions are for Sun 1/9 - Wed 1/12.

NWS - 52/35 49/34 46/33 46/?

TWC - 51/35 53/35 52/28 52/39

Accu - 58/35 53/34 44/36 47/31

There is some disagreement on the amount of cloud cover. The ones with lower daytime highs predict mostly cloudy and the ones with warmer highs predict mostly sunny.

Hopefully that second shot of cold air isn't too bad either.

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It looks like a chilly stretch, but nothing out of the norm for January here. The following predictions are for Sun 1/9 - Wed 1/12.

NWS - 52/35 49/34 46/33 46/?

TWC - 51/35 53/35 52/28 52/39

Accu - 58/35 53/34 44/36 47/31

There is some disagreement on the amount of cloud cover. The ones with lower daytime highs predict mostly cloudy and the ones with warmer highs predict mostly sunny.

Hopefully that second shot of cold air isn't too bad either.

I suspect those numbers are too warm....

Here is a tidbit from one of my local heroes, Jeff Lindner:

Early Next Week:

Much talked about arctic front still on tap to bring very cold air to the region starting late Monday. Suspect clouds will linger much of Monday behind the departing Sunday system keeping highs in the 40’s on Monday even prior to the arctic invasion. Large 1055mb arctic high will begin to surge down the plains Sunday reaching the TX coast late Monday. May need a faster timing with this boundary as such cold dense air masses tend to move very quickly southward. Very strong cold air advection will ensue post boundary by Monday night with NW winds of 20-30mph and possibly higher along the coast. Temperatures will rapidly fall from the 40’s into the 30’s and possibly upper 20’s by Tuesday morning. Models are bouncing around with the idea of keeping clouds in the area at times Tuesday and Wednesday and this will have big effects on overnight lows and afternoon highs in the post frontal air mass. Will continue the trend yesterday of undercutting the GFS guidance numbers by several degrees from Tuesday onward. Will go with lows in the upper 20’s for Tuesday morning (even with strong winds and clouds) and highs only in the low to mid 40’s. For Wednesday will go with lows again in the upper 20’s (could see lower 20’s if skies clear) and highs in the upper 30’s to near 40. Thursday will go with lows in the upper 20’s and highs in the low 40’s. GFS tries to generate some light precipitation by Thursday of next week in the cold air mass, but not confident that this will occur.

Possibly some warming Friday and Saturday of next week before another surge of very cold arctic air arrives late next weekend. Next week to week and a half will feature well below normal temperatures across the entire state. In fact highs may run 15-20 degrees below normal.

Edited by jasons
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Here is a decent snippet from the NWS-Jackson MS. I wanted to post this because it illustrates some of the thinking that goes into posting "official" forecast numbers. Most meteorologists, especially the NWS, tend to be conservative when issuing official numbers.

AS FOR THE SECOND FORECAST ELEMENT OF CONCERN...COLD TEMPS FROM

TUE-THU. THE NICE THING ABOUT THIS IS...MODELS ARE IN DECENT

AGREEMENT ON BUILDING VERY COLD AIR OVER CANADA AND PUSHING IT SOUTH

FOR MID WEEK. JUST HOW MUCH OF THE CORE OF THIS AIRMASS GETS

DELIVERED SOUTH WILL DETERMINE HOW COLD WE WILL ULTIMATELY GET...BUT

INDICATIONS ARE THAT WE WILL BE QUITE CHILLY AND HAVE THE POTENTIAL

TO SEE THE COLDEST CONDITIONS OF THE SEASON. OVERALL...HIGH TEMPS

FOR THIS PERIOD WERE TRIMMED COLDER WITH ONLY SOME SMALL ADJ TO LOWS

FOR WED-THU. AT THIS TIME...DO NOT WANT TO GET TOO AGGRESSIVE AND

WOULD LIKE TO SEE THE MODELS REALLY PUSH THE CORE OF THE COLD INTO

THE REGION BEFORE JUMPING ON THE TEENS FOR LOWS AND STAYING BELOW

FREEZING FOR HIGHS. STAY TUNED FOR WHAT LOOKS TO BE A RETURN TO

WINTER FOR THE SOUTH.

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This is a great thread! It is scary but I am learning many things I have been trying to learn on my own rather unsucessfully. Please keep up this rolling tutorial.

What you look for is what is looking

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I'm always checking the long range for CA. For what it's worth, this is what I saw for next Thurs. Keep in mind that everything changes all the time so this is today.

gfsx_1000_7d.gif

Coastal San Diego, California

Z10b

Dry summer subtropical/Mediterranean

warm summer/mild winter

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It is definitely interesting to see some of the behind the scenes work and conversations. At least behind the scenes to me up to this point. I'm just a casual observer of mainly the forecasted high/low numbers. I have noticed over the years that for my particular area the NWS does indeed tend to be the most conservative. They also tend to be the most accurate. Again, I'm only speaking for my particular area in the last 6 years or so.

This is undoubtably a naive and overly simplistic question, but are the models themselves changed or tweaked over time as they amass more data (their predictions vs real observations)? It seems that if over time the model has a tendency to miss on the cold side that the algorithms used in these models could learn from that and adjust.

I remember reading something a few years back about the hurricane forecast models having what they called a left-bias for hurricanes in the Gulf of Mexico within 72 hours of landfall. Basically, the models tend to predict landfalls left of, or west of in our case, the actual landfall. I believe this held true for Katrina, Rita, and Ike. Interestingly, the models also had a right-bias for the predicted landfalls outside of 72 hours.

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The CPC usually pegs these things and they're showing Florida with normal temps after the 15th. Their forecast condifence is 4 out of 5 due to rising heights and they rarely have confidence levels above 3. The GFS and Euro over 10 days out almost always change from they show initially.

Tampa, Interbay Peninsula, Florida, USA

subtropical USDA Zone 10A

Bokeelia, Pine Island, Florida, USA

subtropical USDA Zone 10B

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The CPC has a more favorable picture for Houston as well. If I'm reading it correctly we fall in the 30% chance of having below avg temps in the 6-10 day (Jan 11-15) and an equal chance of above or below normal temps in the 8-14 day. Hopefully they are correct. It looks like they expect the really cold air to push more easterly and stay north of the gulf coast in general if I'm reading the map correctly.

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It is definitely interesting to see some of the behind the scenes work and conversations. At least behind the scenes to me up to this point. I'm just a casual observer of mainly the forecasted high/low numbers. I have noticed over the years that for my particular area the NWS does indeed tend to be the most conservative. They also tend to be the most accurate. Again, I'm only speaking for my particular area in the last 6 years or so.

This is undoubtably a naive and overly simplistic question, but are the models themselves changed or tweaked over time as they amass more data (their predictions vs real observations)? It seems that if over time the model has a tendency to miss on the cold side that the algorithms used in these models could learn from that and adjust.

I remember reading something a few years back about the hurricane forecast models having what they called a left-bias for hurricanes in the Gulf of Mexico within 72 hours of landfall. Basically, the models tend to predict landfalls left of, or west of in our case, the actual landfall. I believe this held true for Katrina, Rita, and Ike. Interestingly, the models also had a right-bias for the predicted landfalls outside of 72 hours.

Yes, it is very true that NWS-HGX tends to be one of the more conservative offices around and for the most part they do an excellent job.

The models are tweaked and improved over time. In fact, there was a major overhaul of the entire GFS grid placed into operation this past summer (7/28):

Here is a list of past and upcoming changes: http://www.nco.ncep.noaa.gov/pmb/changes/

Edited by jasons
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Couple things going on here-

1.This is all part of a major pattern shift so details are very difficult

to pin down right now,you can find a pretty wide range of opinions right

now from doom and gloom too...eh,not so bad maybe. :rolleyes:

2.Another factor I have not seen brought up recently is the significant lack of snow

cover to foster a large scale event,one caveat to that is,a big enough strong enough

push of cold air doesn't need too much help-

I lived in St.Louis during the 89 event.

I remember looking at my thermometer(wasn't this around X-mas?)and seeing -22F !

I believe officially it was-16F to -18F.

We only had a dusting of snow on the ground at most :blink:

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Still only seeing a few nights near freezing, and one at 27. Hope that's true, as we'll right on through that one, if so.

In my post I sometimes express "my" opinion. Warning, it may differ from "your" opinion. If so, please do not feel insulted, just state your own if you wish. Any data in this post is provided 'as is' and in no event shall I be liable for any damages, including, without limitation, damages resulting from accuracy or lack thereof, insult, or any other damages

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But it could be quite nasty. Give this a read.

http://yourweatherblog.com/2011/01/coldies-this-blasts-for-you/#respond

In my post I sometimes express "my" opinion. Warning, it may differ from "your" opinion. If so, please do not feel insulted, just state your own if you wish. Any data in this post is provided 'as is' and in no event shall I be liable for any damages, including, without limitation, damages resulting from accuracy or lack thereof, insult, or any other damages

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As you might imagine, up here in Oklahoma we're following this, too.

Our state climatologist is making fun of the fear--"arctic-opocalypse" and "cold-magedon"--by reminding us that last January (2010) was quite cold, and this won't be that bad. I'm guessing a low next week of 5 oF or so. I have some electric heat on all except needle palms, Trachycarpus and Sabal minor; even those will be covered. Oops--my Butia won't have heat, either. Wish me luck!

Terdal Farm, Tulsa OK, USA http://www.terdalfarm.com/

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As you might imagine, up here in Oklahoma we're following this, too.

Our state climatologist is making fun of the fear--"arctic-opocalypse" and "cold-magedon"--by reminding us that last January (2010) was quite cold, and this won't be that bad. I'm guessing a low next week of 5 oF or so. I have some electric heat on all except needle palms, Trachycarpus and Sabal minor; even those will be covered. Oops--my Butia won't have heat, either. Wish me luck!

Good luck. Butia will be marginal.

In my post I sometimes express "my" opinion. Warning, it may differ from "your" opinion. If so, please do not feel insulted, just state your own if you wish. Any data in this post is provided 'as is' and in no event shall I be liable for any damages, including, without limitation, damages resulting from accuracy or lack thereof, insult, or any other damages

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I'm always checking the long range for CA. For what it's worth, this is what I saw for next Thurs. Keep in mind that everything changes all the time so this is today.

gfsx_1000_7d.gif

So a giant snail is going to blob down over the middle of the country?

Matt Bradford

"Manambe Lavaka"

Spring Valley, CA (8.5 miles inland from San Diego Bay)

10B on the hill (635 ft. elevation)

9B in the canyon (520 ft. elevation)

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I'm always checking the long range for CA. For what it's worth, this is what I saw for next Thurs. Keep in mind that everything changes all the time so this is today.

gfsx_1000_7d.gif

So a giant snail is going to blob down over the middle of the country?

Matt, that pretty much sums it up.

In my post I sometimes express "my" opinion. Warning, it may differ from "your" opinion. If so, please do not feel insulted, just state your own if you wish. Any data in this post is provided 'as is' and in no event shall I be liable for any damages, including, without limitation, damages resulting from accuracy or lack thereof, insult, or any other damages

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Palmarati,

thanks. This little guy (the Butia) has been in the ground four years. Last winter the lowest was +2 oF, which I don't think we'll get to this time (forecast low is now +10 oF). We had also had an 88 hour period continuously under +20 oF. NOT a good idea for Butia, or any other palm.

The little Butia is always mulched, wrapped and covered with a trash can in cold weather ( under 20 oF). Still, it is always defoliated by winter's end.

I promise, it will get electric heat hereafter. No sense being stupid year after year.

--Erik

Terdal Farm, Tulsa OK, USA http://www.terdalfarm.com/

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Thanks for the info on the models Jason.

It looks like we will avoid the doom and gloom forecasts from last week. It'll be a chilly week for sure, but nothing out of the norm for this time of year and nothing catastrophic. Here's the forecasts for this week for my area.

TWC - 54/36 52/29 49/35 53/37 58/46

NWS - 49/34 48/27 44/33 49/31 56/50

It won't be too bad if these forecasts hold up. 1 night below 30 (upper 20s) and maybe 1-2 more down in the low 30s.

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