Texas Winter 2010-2011

[serenata09]

Is it just me or does the cold weather keep getting pushed further and further back. I seem to remember just a couple days ago that the models were showing the intense cold beginning this coming Sunday...?

I'm walking a fine line of skepticism here. I suppose I just don't want to be disappointed.

[HockeyTx82]

Is it just me or does the cold weather keep getting pushed further and further back. I seem to remember just a couple days ago that the models were showing the intense cold beginning this coming Sunday...?

I'm walking a fine line of skepticism here. I suppose I just don't want to be disappointed.

I think it all starts on Sunday with the real cold coming in later in the week. In waves seems to be the consensus.

[Metalicwx220]

Will the entire south be supportive for snow since there has been talk about a southern active storm train?

[richtrav]

Not sure what the source of this poster's story is, but here is some info on the 1899 freeze that struck Texas. It was also one of the worst arctic invasions in U.S. history:

Hmm, I recognize that article. The sources for the 1899 freeze came from newspapers throughout the state. For the freezes up to 1888 I used a microfilm copy of all the military data for Fort Brown and Ringgold the NCDC had on record, I can't remember exactly when it ended but it was before 1894. They began around 1847 at Fort Brown but had an obvious gap in the 1860s due to the Civil War.

[Ntxw]

Don't take this to the bank yet, but the Canadian shows moisture in the deep cold air. IF this were snow you'd be talking very high ratios from very little moisture, something commonly seen in the higher plains. Just an outside thought from one particular run way far out.

BTW the GGEM has a 1068mb high crossing over which is more in line with the earlier euro run.

[iorange55]

Don't take this to the bank yet, but the Canadian shows moisture in the deep cold air. IF this were snow you'd be talking very high ratios from very little moisture, something commonly seen in the higher plains. Just an outside thought from one particular run way far out.

Keep those nice thoughts coming.

[orangeblood]

Ntxw - I think we're getting into a comfortable enough window to say that this outbreak is coming. My question is - Do you Have any predictions yet on the duration of this event? All models are now showing major height rises across Alaska and Northwestern Canada starting later this week into next week. With any north-south orientation of the jet, that 1060 plus high pressure would have to head south almost due to gravity alone. You're talking about very very dense cold air that with any north-south orientation of the jet for just a short amount of time would bring that south and spread out across most of the country. It would seem like it would take days to scour that kind of air out once it makes it down here ?

[Ntxw]

Ntxw - I think we're getting into a comfortable enough window to say that this outbreak is coming. My question is - Do you Have any predictions yet on the duration of this event? All models are now showing major height rises across Alaska and Northwestern Canada starting later this week into next week. With any north-south orientation of the jet, that 1060 plus high pressure would have to head south almost due to gravity alone. You're talking about very very dense cold air that with any north-south orientation of the jet for just a short amount of time would bring that south and spread out across most of the country. It would seem like it would take days to scour that kind of air out once it makes it down here ?

It's not common you see a duel block come into play like is being depicted in Alaska and Greenland. All of the signals have told such a story so my guess is this won't be a one shot done deal. 2-3 days of freezing or below for DFW can be easily done especially if we have some sort of snow cover to work with. It's January, whatever cold we get will likely stay for awhile even if it's not bitter cold from past experiences.

As cold as last winter was, the deep cold air was not readily available as El Nino depletes source regions. This is a very different situation as tremendously bitter cold has acclimated due to the La Nina. We finally have a mechanism to send it all south, I see nothing stopping it. Srain did a great job pointing that the pattern change would eventually lead to something, and here we have it.

[Texas Snowman]

Is it just me or does the cold weather keep getting pushed further and further back. I seem to remember just a couple days ago that the models were showing the intense cold beginning this coming Sunday...?

I'm walking a fine line of skepticism here. I suppose I just don't want to be disappointed.

I think it all starts on Sunday with the real cold coming in later in the week. In waves seems to be the consensus.

The Dec. 1983 cold invasion came in waves. Reinforcing cold shots, increasing snow cover to the north, and even some snow cover early on here in North Texas all conspired to provide the 295 consecutive hours of sub-freezing weather observed at DFW Airport and in Sherman/Denison (where I live).

I think that will be what will happen here. Perhaps no mega-monster invasion where temperatures plummet to single digits, but one front, then a day or two later, another, and so on.

[Texas Snowman]

Don't take this to the bank yet, but the Canadian shows moisture in the deep cold air. IF this were snow you'd be talking very high ratios from very little moisture, something commonly seen in the higher plains. Just an outside thought from one particular run way far out.

BTW the GGEM has a 1068mb high crossing over which is more in line with the earlier euro run.

If there's one thing that continually catches my eye, it's the various model advertisements of a super high pressure system in the 1060 to 1070 mb range.

To put that into perspective, the highest pressure reading in North America (at least that I've found so far) was in a 1989 arctic high in Alaska when the barometer pegged out at 1078 mb.

And a poster earlier today mentioned that during the Dec. 1983 cold wave, the highest pressure reading was 1063 mb in Montana.

So if a 1060 to 1070 mb high does materialize out of all of this, then IMO this cold invasion will be SEVERE and one that will be remembered for years and years to come.

[AggieSpirit]

So there is a possibility I could layout my tarp on my backyard, and freeze a half inch of water to skate on next week?

[Ntxw]

Though the Euro isn't epic cold like the 12z, it does put north Texas at or below freezing for 72 hours (possibly more but doesn't go out that far yet) so again seems like a long duration event. Virtually all of Texas will be at or below freezing simultaneously at some point.

1052 mb on the Euro

*For the folks who are worried about runs looking bad, this is just one run and the euro not too long ago wasn't showing anything relatively close to a big cold event, it was just the 12z today that things latched on so hang in there as models vary this far out

[AggieSpirit]

Though the Euro isn't epic cold like the 12z, it does put north Texas at or below freezing for 72 hours (possibly more but doesn't go out that far yet) so again seems like a long duration event. Virtually all of Texas will be at or below freezing simultaneously at some point.

1052 mb on the Euro

*For the folks who are worried about runs looking bad, this is just one run and the euro not too long ago wasn't showing anything relatively close to a big cold event, it was just the 12z today that things latched on so hang in there as models vary this far out

Seems like virtually every TV weatherman in the DFW has latched on to the impending cold -- but there seems to be variance among them about how long it will last....

Steve McCauley seems unconvinced this is going to be historic...... but he is a guy who predicted a McFarland effect last year which never materialized.

[richtrav]

Is it just me or does the cold weather keep getting pushed further and further back. I seem to remember just a couple days ago that the models were showing the intense cold beginning this coming Sunday...?

I'm walking a fine line of skepticism here. I suppose I just don't want to be disappointed.

I think it all starts on Sunday with the real cold coming in later in the week. In waves seems to be the consensus.

The Dec. 1983 cold invasion came in waves. Reinforcing cold shots, increasing snow cover to the north, and even some snow cover early on here in North Texas all conspired to provide the 295 consecutive hours of sub-freezing weather observed at DFW Airport and in Sherman/Denison (where I live).

I think that will be what will happen here. Perhaps no mega-monster invasion where temperatures plummet to single digits, but one front, then a day or two later, another, and so on.

These are probably more common historically than the "Big Ones", I can think of numerous winters where below normal temperatures fall into a kind of rut and you'll get some pretty hard freezing but nothing along the lines of an 1899 or 1989 (just look at this past Dec in Florida). I'm too lazy to look them all up right now, but here are the daily temperature readings from 1885 to 2002 for San Antonio for Dec-Feb:

http://s73.photobucket.com/albums/i202/ ... r%20temps/

In all those thousands of numbers you can pick out some patterns if you know where to look. Besides the obvious well known freezes (like Jan 1886 and '88, Feb 1895 and '99, Jan 1918, '30, '49, '51, '62 and Dec '83 and '89) you'll find that lesser outbreaks comparable to last year's freeze used to be fairly commonplace (look for instance at the beginning of Jan 1887, mid Jan 1892, around Dec 20 1924 and '29, Feb 7 1933 among others). The list goes on and on, we've just been used to so many years of winters free of severely cold days that any cold outbreak now seems like it's some sort of blockbuster event.

BTW I believe that monster 1078mb high was associated with the February 1989 Arctic outbreak, when intensely cold air had been pooling for weeks in Alaska. The weather forecasters knew at the time that it was going to come down and it was going to be big - they were comparing it to 1951 - but though it was a long outbreak it turned out to be nowhere nearly as intense as the 1951 freeze

[Portastorm]

Morning folks!

Here’s your morning report from Texas-based NWSFOs … and relevant snippets regarding next week:

Amarillo:

THE ECMWF SHOWING THE FIRST PUSH OF COLDER AIR ARRIVING ON SATURDAY
FOLLOWED BY A SECONDARY SURGE OF MUCH COLDER AIR SUNDAY. THIS
SECONDARY SURGE WILL CONTAIN THE COLDER CANADIAN OR MODIFIED ARCTIC
AIR WHICH WILL IMPACT THE PANHANDLES NEXT WEEK. IN THE MEANTIME...LIGHT
WINDS EXPECTED TONIGHT AND WEDNESDAY AS A COOL SURFACE RIDGE QUICKLY
SHIFT EAST TODAY AS LEE SIDE TROUGH DEVELOPS BY THIS AFTERNOON AND
MOVES ACROSS THE PANHANDLES TONIGHT. A SURFACE RIDGE WILL BUILD IN
BEHIND THE TROUGH TONIGHT AND EARLY WEDNESDAY BEFORE SURFACE LOW AND
TROUGH DEVELOPS BY WEDNESDAY AFTERNOON OVER NORTHEAST AND EASTERN NM.
THE SURFACE LOW AND TROUGH MOVE ACROSS THE PANHANDLES BY WEDNESDAY
NIGHT AND THURSDAY KEEPING THE WINDS LIGHT. WARMER DOWNSLOPING
SURFACE FLOW FRIDAY AHEAD OF THE WEEKEND SYSTEM WHICH WILL ALLOW FOR
ABOVE SEASONABLE TEMPS LATE THIS WEEK AND CONTINUED DRY CONDITIONS.

Midland:

THE SAME CANNOT BE SAID OF A DEEP UPPER TROUGH DEVELOPING IN
CANADA AND DROPPING SOUTH ON MONDAY. THERE IS GOOD AGREEMENT THAT
VERY COLD AIR WILL DROP SOUTH EARLY MONDAY AND PERSIST THROUGH THE
REMAINDER OF THE FORECAST PERIOD. WENT AT OR BELOW GUIDANCE ON
TEMPS THE LATTER PART OF THE FORECAST PERIOD WITH STRONG HIGH
PRESSURE BUILDING SOUTH THOUGH TEMPS MAY STILL NEED TO BE ADJUSTED
A LITTLE LOWER.

San Angelo:

THE MAJORITY OF MY ATTENTION IS FOCUSED ON THE POTENTIAL FOR A
SUBSTANTIAL COLD FRONT FOR NEXT WEEK. AN ARCTIC COLD FRONT IS POISED
TO ARRIVE SUNDAY NIGHT BRINGING MUCH COLDER TEMPERATURES TO WEST
CENTRAL TX. THE SYNOPTIC PATTERN BY THE WEEKEND RESEMBLES THAT OF
PATTERNS PRECEDING OTHER SIGNIFICANT COLD SNAPS ACROSS THE THE STATE
OF TX /MCFARLAND/. THE RIDGE OVER THE STATE OF AK WILL PROVIDE A
CROSS POLAR COMPONENT TO THE FLOW WHICH WILL TAP INTO VERY COLD
SIBERIAN AIR. THIS WILL RENDER MOS TEMPS ESSENTIALLY USELESS FOR THE
LAST FEW DAYS OF THE PACKAGE. HIGH TEMPS ON MONDAY WILL RELY HEAVILY
ON THE ACTUAL TIMING OF THE FRONT AND THE PRESENCE OF ANY LOW CLOUD
COVER. I CURRENTLY HAVE HIGHS IN THE 40S FOR MUCH OF THE CWA AND
THAT COULD BE RATHER GENEROUS IF THE FRONT ARRIVES BY 12Z. BY
TUESDAY...HIGH TEMPS ARE EXPECTED TO BE IN THE MID 30S IN MOST
AREAS. LOW TEMPERATURES ACCOMPANYING THIS AIRMASS WILL BE IN THE
TEENS AND LOWER 20S. THIS COULD BE A PROLONGED COLD SNAP AS THE
MODELS KEEP H85 TEMPS BELOW FREEZING THROUGH PRETTY MUCH THE ENTIRE
WEEK. AT THIS TIME...IT APPEARS THAT IF ANY PRECIPITATION WERE TO
ACCOMPANY THIS FRONT IT WOULD BE ACROSS THE EXTREME EAST/SOUTH
SUNDAY NIGHT BUT AS FAST AS THIS FRONT SHOULD BE MOVING ANY PRECIP
WOULD NOT LAST LONG. OF COURSE...WE ARE STILL LOOKING OUT BEYOND DAY
5 AND THE FORECAST COULD UNDERGO SUBSTANTIAL MODIFICATION.
HOWEVER...THE MODELS HAVE BEEN FAIRLY CONSISTENT WITH THIS SCENARIO
FOR SEVERAL DAYS SO CONFIDENCE IS INCREASING WITH EACH RUN.

Austin/San Antonio:

WINDY AND MUCH COLDER MONDAY WITH
TEMPERATURES WILL BELOW NORMAL AT LEAST INTO THE MID WEEK. MOST
LIKELY THE COLDEST TEMPERATURES OF THE SEASON...BUT DRY. ECMWF/GFS
DO SHOW SOME S/W ENERGY MOVING ACROSS W TX LATE WEDNESDAY(DAY 8)
THAT COULD PRODUCE SOME VIRGA OR FLURRIES. OTHERWISE HAVE
GENERALLY GONE WITH 20S FOR LOWS AND 40S FOR HIGHS BY TUESDAY IN
LINE WITH SURROUNDING OFFICES.

Corpus Christi:

DAY 8 AND BEYOND...ALL INDICATIONS POINT TO AN ARCTIC OUTBREAK FOR
EARLY NEXT WEEK WITH A SIGNIFICANT ARCTIC FRONT ON MONDAY. MODELS
HAVE BEEN FLIPPING BACK AND FORTH ON HOW LONG THE COLD BLAST MAY
LAST...BUT THEY DO AGREE THAT 1050MB PLUS HIGH PRESSURE WILL DIVE
INTO MONTANA EARLY NEXT WEEK. THIS WILL ALLOW VERY COLD AIR TO SINK
SOUTH THROUGH THE SOUTHERN PLAINS AND FILTER INTO THE REGION
BEGINNING ON TUESDAY. TEMPERATURES ON TUESDAY MAY NOT GET OUT OF THE
40S FOR HIGHS. STAY TUNED.

Brownsville:

CLEAR CONDITIONS EARLY MONDAY WILL
GIVE WAY TO INCREASING CLOUDINESS AS A STRONG COLD FRONT MOVES
SOUTH INTO TEXAS. THR FRONT WILL PUSH THROUGH LATE MONDAY BRINGING
COLDER AIR AND THE POSSIBILITY OF LIGHT PRECIP ALONG THE RIO
GRANDE. OTHERWISE...TUESDAY WILL BE CLEARER AND COLDER WITH TEMPS
5 DEGREES COLDER THAN MONDAY OVERALL. TEMPS WILL BE SIGNIFICANTLY
COLDER ON TUESDAY UNDER SUNNY SKIES.


Lubbock:

.LONG TERM...
A MAJOR CHANGE TO THE WEATHER PATTERN MAY COME NEXT WEEK WITH A
STRONG COLD AIR DUMP. MEANWHILE...NORTHWEST FLOW ALOFT WILL PERSIST
THROUGH THE REST OF THIS WEEK. A WEAK SHORT WAVE WILL MOVE THROUGH
ON THURSDAY AFTERNOON AND EVENING. HOWEVER...THERE IS LITTLE TO NO
LIFT ASSOCIATED WITH THIS FEATURE. FURTHERMORE...MOISTURE WILL BE
VERY LIMITED. WEST TEXAS WILL THEN SEE SHORTWAVE RIDGING ON FRIDAY
BEFORE THE NEXT WEATHER MAKER ENTERS THE SCENE.

THE CLOSED UPPER LOW SITTING OFF THE CALIFORNIA COAST THIS WEEK WILL
MOVE ONSHORE FRIDAY HEADING TOWARDS THE AREA. AS THE SYSTEM MOVES
ACROSS THE DESERT SOUTHWEST...IT WILL OPEN UP AND WEAKEN BEFORE IT
ARRIVES IN WEST TEXAS. THERE ARE STILL MODEL DIFFERENCES ON THE
LOCATION THE SHORT WAVE WILL TAKE EVEN THOUGH THE EURO HAS NOW
TRENDED TOWARDS THE OPERATIONAL RUN OF THE GFS. WILL FAVOR THE
GFSE SOLUTION AT THE MOMENT. EFFECTS OF THIS SYSTEM MAY COME IN
THE FORM OF SHOWERS MOSTLY OFF THE CAPROCK FROM SATURDAY INTO
EARLY SUNDAY.

AFTER THE WAVE RAPIDLY MOVES TO THE EAST A STRONGER PIECE OF ENERGY
WILL DROP OUT OF THE CENTRAL ROCKIES. HOWEVER...THE STRONGEST LIFT
FROM THIS SYSTEM WILL BE TO THE NORTH OF THE AREA LATE SUNDAY INTO
MONDAY. HAVE ADDED A SLIGHT CHANCE OF POPS FOR THE SOUTHEASTERN
PANHANDLE FOR THIS TIME PERIOD. THE PREVIOUSLY ANTICIPATED ARCTIC
AIR DUMP FOR NEXT WEEK IS STILL VALID. A STRONG FRONT WILL MOVE
THROUGH THE AREA EARLY ON MONDAY LEADING TO A PROLONGED COLD PERIOD.
JDV

Houston/Galveston:

(they didn’t really comment at all)

Fort Worth:

(it’s so long I will post it in a separate post)

[Portastorm]

And the "winner" of the morning AFDs comes from NWSFO Fort Worth:

MAIN WEATHER STORY IS THE COLDER WEATHER EXPECTED INTO THE REGION
NEXT WEEK. THERE REMAINS EXCELLENT AGREEMENT AMONG THE MODELS THAT
A PATTERN CHANGE WILL OCCUR AS BLOCKING UPPER HIGHS/LOWS DEVELOP
AND PERSIST ACROSS THE NORTHERN LATITUDES. A COLD AIR MASS WILL
BEGIN TO DEVELOP AND ORGANIZE ACROSS WESTERN CANADA THIS WEEKEND
WITH SURFACE TEMPS THERE BEGINNING TO FALL BELOW 0 AS A LARGE
SPRAWLING SURFACE HIGH GATHERS INTENSITY. THIS CANADIAN AIR MASS
IS POISED TO MOVE SOUTH AND ARRIVE INTO NORTH TEXAS BEGINNING
MONDAY. SINCE THE UPPER PATTERN STAYS BLOCKED...THE GATES TO THE
NORTH WILL REMAIN OPEN AND COLD AIR WILL CONTINUE TO POUR SOUTH
INTO THE CENTRAL US FOR SEVERAL DAYS. THUS IT IS WITH HIGH
CERTAINTY THAT WE CAN SAY AN EXTENDED PERIOD OF COLDER THAN
NORMAL WEATHER WILL OCCUR IN NORTH TEXAS NEXT WEEK.

AS FAR AS HOW COLD...AND WHETHER THIS EVENT WILL BE ONE OF THOSE
MEMORABLE DECADE EVENTS...IS ANOTHER QUESTION. AT LEAST THROUGH
FRIDAY JAN 14TH...ODDS ARE THAT THIS COLD SPELL WILL NOT BE
ANYWHERE NEAR RECORD TERRITORY AND LOOKS COMPARABLE TO THE ONE
LAST YEAR IN EARLY JANUARY. LAST NIGHT I WROTE ABOUT THE BENEFITS
OF ANALYSIS OF THE SOURCE REGION OF THESE COLD AIR MASSES...
PARTICULARLY AT THE 500MB-700MB LEVEL. I DUG UP THE UPPER AIR DATA
FROM A DOZEN OF OUR BIGGEST COLD SNAPS SINCE 1970. THESE HISTORIC
ARCTIC OUTBREAKS UNANIMOUSLY CONTAINED 500-700MB TEMPS 5 TO 10 DEG
C COLDER THAN WHAT ANY MODEL IS FORECASTING OVER CANADA THIS
WEEKEND. IN ADDITION 850MB TEMPS ACROSS THE NORTHERN US ARE
FORECAST TO BE ABOUT 5 DEG C WARMER EARLY NEXT WEEK THAN WHAT OUR
SIGNIFICANT OUTBREAKS HAD. THUS WE CAN MAKE FORECAST TEMPERATURE
EXTRAPOLATIONS BASED OFF A MODEL/S UPPER AIR FORECASTS 5 DAYS OUT
RATHER THAN RELYING ON A MODEL/S SURFACE TEMP FORECAST 10 DAYS OUT
WHICH IS OBVIOUSLY PRONE TO MORE ERRORS.

SO FOR THE SPECIFICS...MONDAY/S HIGHS SHOULD LIKELY BE IN THE 40S
AS FROPA OCCURS THAT MORNING. LOWS MONDAY NIGHT SHOULD BE IN THE
20S AREA WIDE WITH BREEZY NORTH WINDS CONTINUING. HIGHS TUESDAY
THROUGH FRIDAY LOOK TO STAY IN THE 30S AREA WIDE DESPITE GENERALLY
SUNNY SKIES. WINDS SHOULD SUBSIDE MORE BY MID LATE WEEK WITH LOWS
LIKELY IN THE TEENS TO LOW 20S EACH NIGHT.

BEYOND JAN 14TH...IT IS TOUGH TO SAY EXACTLY WHAT WILL HAPPEN.
YESTERDAY/S MODEL RUNS WERE MORE BULLISH THAT NEXT WEEK/S COLD
SPELL WAS JUST THE START OF SOMETHING MORE SERIOUS. THE LATEST
GFS/ECMWF/GEM OPERATIONAL RUNS AND ENSEMBLE MEANS AT 240 HOURS ARE
DEPICTING AN UPPER LEVEL PATTERN NOT EXACTLY FAVORABLE FOR A
HISTORIC OUTBREAK. THEY HAVE ALL TRENDED THE BLOCKING HIGH OVER
ALASKA EITHER TOO FAR NORTH OR TOO FAR WEST INTO SIBERIA. THIS
MEANS THE POSITIVELY TILTED UPPER TROUGH AXIS OVER THE SW US /A
CRUCIAL COMPONENT TO GET AN ARCTIC OUTBREAK HERE...AND A KEY TO
MEETING THE REQUIREMENTS OF THE SO-CALLED MCFARLAND PATTERN
SIGNATURE/ BECOMES IN QUESTION...SINCE A POSITIVE TILT TROUGH OR
KINK OFTEN NATURALLY DEVELOPS SOUTHEAST OF AN UPPER HIGH. WITHOUT
THIS TROUGH THE REAL ARCTIC AIR JUST HAS A TOUGH TIME MAKING IT
THIS FAR SOUTH. HOWEVER...ABOUT 1/3 OF THE ENSEMBLE MEMBERS KEEP
THIS SW TROUGH IN TACT...AND THEY SHOW A VERY COLD/INTENSE POLAR
LOW DEVELOPING OVER CANADA AND THE US IN 10 DAYS. LOTS OF
UNCERTAINTY AND MODELS WILL CONTINUE TO CHANGE DAILY. BUT THE
REASON WHY WE ARE WATCHING THIS SO CLOSELY IS BECAUSE A 30 PERCENT
CHANCE OF OCCURRENCE IS PRETTY HIGH FOR AN EVENT WHICH WOULD HAVE
ENORMOUS AND WIDESPREAD ECONOMIC IMPLICATIONS FOR OUR REGION...AS
WE LEARNED IN THE DEEP FREEZES OF 83 AND 89.

[orangeblood]

They must have made some new hires over here in Fort Worth. Their discussions have been much more informative compared to years past.

[DFW Stormwatcher]

They must have made some new hires over here in Fort Worth. Their discussions have been much more informative compared to years past.

Maybe, but even the guys that have been there are being more detailed in their discussions at FWD. I think they just got their butts kicked pretty bad last year during the winter, so they're trying to give us a more detailed explanation of their forecasts so we at least are aware of the worst case scenario rather than being blindsided. And anyone who wasn't paying attention to this forum last year in DFW was blindsided a couple of times.

Thats the reason I signed up for this forum in the first place last year. FWD was producing vague and erroneous forecasts during the previous couple of winters. Before this I depended more on the Oklahoma City office for accurate winter weather advisories, but Fort Worth has improved alot.

[txagwxman]

Looks like 18-20F next week Dallas for lows now vs 12F earlier.



Canadian model looks colder end of the week though. What is keeping this from blowing out is the ridge over Alaska---it is almost too strong, and a trough undercuts the ridge over BC which hangs the intense cold up. But that Gem is cold enough for me.

[orangeblood]

And the "winner" of the morning AFDs comes from NWSFO Fort Worth:

MAIN WEATHER STORY IS THE COLDER WEATHER EXPECTED INTO THE REGION
NEXT WEEK. THERE REMAINS EXCELLENT AGREEMENT AMONG THE MODELS THAT
A PATTERN CHANGE WILL OCCUR AS BLOCKING UPPER HIGHS/LOWS DEVELOP
AND PERSIST ACROSS THE NORTHERN LATITUDES. A COLD AIR MASS WILL
BEGIN TO DEVELOP AND ORGANIZE ACROSS WESTERN CANADA THIS WEEKEND
WITH SURFACE TEMPS THERE BEGINNING TO FALL BELOW 0 AS A LARGE
SPRAWLING SURFACE HIGH GATHERS INTENSITY. THIS CANADIAN AIR MASS
IS POISED TO MOVE SOUTH AND ARRIVE INTO NORTH TEXAS BEGINNING
MONDAY. SINCE THE UPPER PATTERN STAYS BLOCKED...THE GATES TO THE
NORTH WILL REMAIN OPEN AND COLD AIR WILL CONTINUE TO POUR SOUTH
INTO THE CENTRAL US FOR SEVERAL DAYS. THUS IT IS WITH HIGH
CERTAINTY THAT WE CAN SAY AN EXTENDED PERIOD OF COLDER THAN
NORMAL WEATHER WILL OCCUR IN NORTH TEXAS NEXT WEEK.

AS FAR AS HOW COLD...AND WHETHER THIS EVENT WILL BE ONE OF THOSE
MEMORABLE DECADE EVENTS...IS ANOTHER QUESTION. AT LEAST THROUGH
FRIDAY JAN 14TH...ODDS ARE THAT THIS COLD SPELL WILL NOT BE
ANYWHERE NEAR RECORD TERRITORY AND LOOKS COMPARABLE TO THE ONE
LAST YEAR IN EARLY JANUARY. LAST NIGHT I WROTE ABOUT THE BENEFITS
OF ANALYSIS OF THE SOURCE REGION OF THESE COLD AIR MASSES...
PARTICULARLY AT THE 500MB-700MB LEVEL. I DUG UP THE UPPER AIR DATA
FROM A DOZEN OF OUR BIGGEST COLD SNAPS SINCE 1970. THESE HISTORIC
ARCTIC OUTBREAKS UNANIMOUSLY CONTAINED 500-700MB TEMPS 5 TO 10 DEG
C COLDER THAN WHAT ANY MODEL IS FORECASTING OVER CANADA THIS
WEEKEND. IN ADDITION 850MB TEMPS ACROSS THE NORTHERN US ARE
FORECAST TO BE ABOUT 5 DEG C WARMER EARLY NEXT WEEK THAN WHAT OUR
SIGNIFICANT OUTBREAKS HAD. THUS WE CAN MAKE FORECAST TEMPERATURE
EXTRAPOLATIONS BASED OFF A MODEL/S UPPER AIR FORECASTS 5 DAYS OUT
RATHER THAN RELYING ON A MODEL/S SURFACE TEMP FORECAST 10 DAYS OUT
WHICH IS OBVIOUSLY PRONE TO MORE ERRORS.

SO FOR THE SPECIFICS...MONDAY/S HIGHS SHOULD LIKELY BE IN THE 40S
AS FROPA OCCURS THAT MORNING. LOWS MONDAY NIGHT SHOULD BE IN THE
20S AREA WIDE WITH BREEZY NORTH WINDS CONTINUING. HIGHS TUESDAY
THROUGH FRIDAY LOOK TO STAY IN THE 30S AREA WIDE DESPITE GENERALLY
SUNNY SKIES. WINDS SHOULD SUBSIDE MORE BY MID LATE WEEK WITH LOWS
LIKELY IN THE TEENS TO LOW 20S EACH NIGHT.

BEYOND JAN 14TH...IT IS TOUGH TO SAY EXACTLY WHAT WILL HAPPEN.
YESTERDAY/S MODEL RUNS WERE MORE BULLISH THAT NEXT WEEK/S COLD
SPELL WAS JUST THE START OF SOMETHING MORE SERIOUS. THE LATEST
GFS/ECMWF/GEM OPERATIONAL RUNS AND ENSEMBLE MEANS AT 240 HOURS ARE
DEPICTING AN UPPER LEVEL PATTERN NOT EXACTLY FAVORABLE FOR A
HISTORIC OUTBREAK. THEY HAVE ALL TRENDED THE BLOCKING HIGH OVER
ALASKA EITHER TOO FAR NORTH OR TOO FAR WEST INTO SIBERIA. THIS
MEANS THE POSITIVELY TILTED UPPER TROUGH AXIS OVER THE SW US /A
CRUCIAL COMPONENT TO GET AN ARCTIC OUTBREAK HERE...AND A KEY TO
MEETING THE REQUIREMENTS OF THE SO-CALLED MCFARLAND PATTERN
SIGNATURE/ BECOMES IN QUESTION...SINCE A POSITIVE TILT TROUGH OR
KINK OFTEN NATURALLY DEVELOPS SOUTHEAST OF AN UPPER HIGH. WITHOUT
THIS TROUGH THE REAL ARCTIC AIR JUST HAS A TOUGH TIME MAKING IT
THIS FAR SOUTH. HOWEVER...ABOUT 1/3 OF THE ENSEMBLE MEMBERS KEEP
THIS SW TROUGH IN TACT...AND THEY SHOW A VERY COLD/INTENSE POLAR
LOW DEVELOPING OVER CANADA AND THE US IN 10 DAYS. LOTS OF
UNCERTAINTY AND MODELS WILL CONTINUE TO CHANGE DAILY. BUT THE
REASON WHY WE ARE WATCHING THIS SO CLOSELY IS BECAUSE A 30 PERCENT
CHANCE OF OCCURRENCE IS PRETTY HIGH FOR AN EVENT WHICH WOULD HAVE
ENORMOUS AND WIDESPREAD ECONOMIC IMPLICATIONS FOR OUR REGION...AS
WE LEARNED IN THE DEEP FREEZES OF 83 AND 89.

After reading this mornings discussion out of Fort Worth, it would appear that the scenario they're depicting would bring more energy/moisture into the picture with the Pacific Coast ridge not being as strong. In order for the positively tilted SW US trough to get established, you would need a fairly strong Pacific Coast ridge to be intact. With the weaker ridge, more energy/moisture can come out of the Pacific thus bringing more chances of snow/ice (still cold but not bitterly cold) compared to just bitterly cold/dry conditions. Which of the scenarios do you want - snow/ice storms or a prolonged severe cold event ?? and please correct me if I'm wrong in my interpretation of this mornings discussion.