Texas/MX Obs And Discussion Thread.

[Srain]

Looks like an interesting week or two ahead. The 00Z Euro is in agreement regarding to Arctic Air spilling S into the lower 48 later next weekend and the following week. Here are some discussions from various NWS offices concerning the mid week rains, next weekend storm and beyond...

HGX:

THIS WILL LEAD TO

AN ONSHORE FLOW RETURNING AND AN INCREASE IN MOISTURE. LOW LEVEL

CONVERGENCE WILL INCREASE AS COASTAL TROUGHING DEVELOPS. FCST

SOUNDINGS SHOW PW VALUES INCREASING TO BETWEEN 1.2 AND 1.4 INCHES

BY TUESDAY NIGHT. JET DYNAMICS LOOK WEAK AND SOUNDINGS SUGGEST

CAPPING WILL REMAIN IN PLACE. THE LOW LEVEL CONVERGENCE AND

DEEPENING MOISTURE BENEATH THE CAP SHOULD YIELD SCATTERED SHOWERS

TUESDAY AFTERNOON AND TUESDAY NIGHT. A WEAK COLD FRONT WILL CROSS

SOUTHEAST TEXAS ON WEDNESDAY AND THIS FEATURE WILL ALSO TRIGGER

SHOWERS. DRIER AIR WILL WORK INTO THE REGION ON THURSDAY BUT SKIES

WILL BE SLOW TO CLEAR. HIGH PRESSURE WILL AGAIN SETTLE OVER THE

SOUTHERN PLAINS AND BRING ANOTHER COOL MORNING ON FRIDAY. LONG

RANGE MODELS ARE PRETTY GOOD AGREEMENT WITH BRINGING A POTENT

SHORT WAVE ACROSS TEXAS ON SATURDAY NIGHT. JET STRUCTURE IS

IMPRESSIVE WITH THIS SYSTEM AND RAIN CHANCES WILL INCREASE AGAIN

LATE SATURDAY OR SATURDAY NIGHT. THE SYSTEM IS PROGRESSIVE AND

WILL EXIT THE REGION EARLY SUNDAY.

Corpus Christi:

LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...THE PERIOD BEGINS WITH

SURFACE HIGH PRESSURE ACROSS THE SOUTHEAST... WITH ONSHORE FLOW AND

MOISTURE RETURNING TO SOUTH TEXAS. A WARM FRONT IS EXPECTED TO LIFT

NORTH ACROSS SOUTH TEXAS LATE MONDAY INTO TUESDAY AND ISENTROPIC

LIFT WILL CAUSE AN INCREASE IN CLOUD COVER. THE INVERSION WILL LIFT

TO 800-850MB BY TUESDAY MORNING SO MAY GET A FEW SPRINKLES OR LIGHT

RAIN. LEFT THE 20 POPS IN ALONG THE COASTAL BEND AFTER MIDNIGHT.

RAISED OVERNIGHT LOWS INTO THE 50S TO AROUND 60 FOR THE EXPECTED

CLOUD COVER. INVERSION HEIGHTS LIFT TO AROUND 750MB DURING THE DAY

ON TUESDAY AS ISENTROPIC ASCENT CONTINUES...SO LIGHT RAIN AND

SPRINKLES ARE EXPECTED ACROSS THE EASTERN TWO-THIRDS OF SOUTH TEXAS.

THEREFORE...BUMPED UP POPS TO CHANCE CATEGORY. OVERALL PRECIPITATION

AMOUNTS ARE ONLY EXPECTED TO BE A TRACE TO AROUND 1/10 OF AN INCH.

HIGHS WILL BE IN THE 60S TO LOWER 70S ON TUESDAY.

A WEAK SHORTWAVE WILL SLIDE ACROSS THE FOUR CORNERS REGION AND BEGIN

TO SHEAR OUT AS IT MOVES INTO THE SOUTHERN PLAINS ON WEDNESDAY. THIS

WILL HELP PUSH A FRONTAL BOUNDARY THROUGH THE REGION WEDNESDAY

AFTERNOON OR EVENING. INTRODUCED SLIGHT CHANCE POPS FOR TUESDAY

NIGHT AND WEDNESDAY TO ACCOUNT FOR THIS. DRIER AIR IS THEN EXPECTED

TO FILTER INTO THE REGION THROUGH THE END OF THE WEEK. WITH MORE

SUNSHINE ON WEDNESDAY DUE TO THE BOUNDARY...TEMPERATURES WILL LIKELY

WARM INTO THE 70S TO AROUND 80.

MODELS DIVERGE FOR NEXT WEEKEND...WITH THE GFS MUCH WETTER THAN THE

ECMWF. THE GFS MOVES A BAGGY TROUGH ACROSS SOUTH TEXAS ON

SATURDAY...WITH GOOD DYNAMICS OVER THE REGION...WHICH WOULD PRODUCE

WIDESPREAD RAINFALL. THE ECMWF HAS MORE OF A CLOSED UPPER LOW AND IS

FURTHER NORTH...AND RAIN CHANCES WOULD BE MINIMAL FOR MOST OF THE

AREA AS WINDS ALOFT VEER SOUTHWESTERLY AHEAD OF THE SHORTWAVE. LEFT

SLIGHT CHANCE AND CHANCE POPS IN FOR SATURDAY AND SATURDAY NIGHT.

Austin/San Antonio:

LOWER CLOUDS ARE

EXPECTED TO BEGIN IN THE DAYTIME MONDAY WITH A FEW SPRINKLES

EXPECTED TO DEVELOP BY TUESDAY. LIGHT SHOWERS TUESDAY NIGHT AND

WEDNESDAY SHOULD END WITH A CLIPPER STYLE FRONT LATE WEDNESDAY.

THIS FRONT SHOWS INCREASING STRENGTH IN THE RUN-TO-RUN MODEL

TRENDS OF THE GFS...SO HAVE MADE SOME COOLER ADJUSTMENTS TO TEMPS

IN THE THURSDAY-FRIDAY TIME FRAME. MODELS ARE COMING INTO SLIGHTLY

BETTER AGREEMENT ON THE SOUTHERN US STORM TRACK FOR NEXT

WEEKEND...BUT THERE REMAINS CONSIDERABLE VARIATIONS IN STRENGTH

AND TIMING. WILL KEEP WITH THE GFS TIMING BUT CAP RAIN CHANCES AT

20-30 PERCENT LATE SATURDAY.

Dallas/Ft Worth:

LATEST MODEL GUIDANCE IS COMING INTO BETTER AGREEMENT FOR THE LATE

WEEK AND NEXT WEEKEND FORECAST...HOWEVER IS STILL PRONE TO SOME

MAJOR CHANGES REGARDING STRENGTH/TIMING OF THE MAIN PLAYERS. OF

INTEREST IS AN UPPER LOW OFF THE CALIFORNIA COAST THAT SHOULD HEAD

EASTWARD AND ACROSS THE STATE NEXT WEEKEND. WILL INTRODUCE SOME

POPS SATURDAY...WITH BEST CHANCES COMING SATURDAY NIGHT. VARIOUS

OPERATIONAL RUNS OF THE GFS THE LAST 2 DAYS HAVE BEEN TRYING TO

INDICATE THE POTENTIAL FOR WINTRY PRECIP. GIVEN THE UPPER PATTERN

IT WILL BE TOUGH TO GET THE ENTIRE COLUMN BELOW FREEZING AND THIS

HYPOTHESIS IS VERIFIED BY LATEST MODELS ALL SUGGESTING WARM 850MB

TEMPS OF 2-4C AS THE SYSTEM MOVES ACROSS. OF COURSE IF THE UPPER

LOW IS STRONGER THAN FORECAST...THERE MAY BE SOME DYNAMIC COOLING

TO ALLOW FOR SUBFREEZING TEMPS OR SNOW POTENTIAL...BUT THERE IS

LITTLE ENSEMBLE OR OPERATIONAL SUPPORT FOR THIS SCENARIO NOW. ANY

WINTER PRECIP THREAT WOULD LIKELY BE IN THE FORM OF FREEZING RAIN.

THE KEY TO THIS POTENTIAL IS GOING TO BE THE POSITIONING OF THE

EAST COAST UPPER TROUGH AND THE STRENGTH OF THE SURFACE HIGH

MOVING INTO THE MIDWEST FRIDAY/SATURDAY. THIS WILL CONTROL JUST

HOW MUCH COLD/DRY AIR IS ABLE TO BLEED INTO THE REGION FROM THE

NORTHEAST BEFORE THE UPPER DISTURBANCE ARRIVES. LATEST ECMWF IS

THE WEAKEST WITH THIS HIGH...HAS LITTLE TO NO COLD AIR IN PLACE

AND TEMPS WELL INTO THE 60S SATURDAY WHEN THE PRECIP IS FALLING.

THE CANADIAN/UKMET HAS THE STRONGEST HIGH AND THUS COLDEST TEMPS.

THE GFS OFFERS THE COMPROMISE WITH MOST OF THE COLD AIR REMAINING

NORTHEAST...BUT EVAPORATIVE COOLING RESULTING IN TEMPS FALLING

INTO THE 30S WHEN PRECIP ARRIVES. WILL SIDE WITH THE 0Z GFS AND

PUT LOWS SAT NIGHT JUST ABOVE FREEZING AND THUS GET TO KEEP PRECIP

TYPE AS ALL RAIN. OBVIOUSLY WILL CONTINUE TO WATCH CLOSELY.

AND FINALLY WE HAVE BEEN SEEING SOME CONSISTENCY TAKE HOLD IN ALL

THE MODELS BEYOND 7 DAYS WITH RESPECT TO A PERIOD OF COLDER THAN

NORMAL WEATHER FOR THE SECOND WEEK OF JANUARY. AN UPPER LEVEL REX

BLOCK OFF GREENLAND/NEWFOUNDLAND HAS BEEN A STAPLE OF THIS

WINTER/S UPPER PATTERN AND HAS RESULTED IN BELOW NORMAL TEMPS IN

THE EASTERN US. THIS BLOCKING FEATURE IS FORECAST TO GRADUALLY

HEAD WESTWARD DURING THE NEXT COUPLE WEEKS...REACHING ALASKA AND

WESTERN CANADA BY 10 DAYS. THIS SHOULD RESULT IN A PROLONGED FETCH

OF CANADIAN AND PERHAPS EVENTUALLY TRUE ARCTIC AIR INTO MUCH OF

THE COUNTRY. TOO EARLY TO OFFER ANY EXACT NUMBERS...BUT THIS MAY

END UP BEING OUR BIGGEST COLD SPELL OF THE 2010-11 WINTER.

Amarillo:

A COLD FRONT THEN BACKS IN FROM THE NORTHEAST FRIDAY NIGHT...BUT HOW

FAR AND HOW QUICKLY SOUTHWEST THE COLD AIR PENETRATES WILL DEPEND

LARGELY ON THE TRACK AND TIMING OF THE SOUTHERN STREAM LOW WHICH

REMAINS QUITE UNCERTAIN ATTM. FOR NOW WILL PAINT A DECENT

NORTHEAST/SOUTHWEST TEMP GRADIENT ON SATURDAY...BASICALLY A BLEND

BETWEEN THE COLDER ECMWF AND WARMER GFS SOLUTION. SPEAKING OF THE

SOUTHERN STREAM LOW...THE 01/12Z ECMWF FEATURED A TRACK THAT KEPT

MOST IF NOT ALL OF THE PRECIP JUST SOUTH OF THE CWA SATURDAY/SATURDAY

NIGHT. THE LATEST 02/00Z RUN IS MUCH MORE PROGRESSIVE WITH THE

LOW...SWINGING IT THROUGH NOW FRIDAY NIGHT/EARLY SATURDAY...AND ISN/T

TAPPING ENOUGH DEEP MOISTURE TO GENERATE PRECIP UNTIL IT/S EAST OF

THE CWA GIVEN THE QUICKER SOLUTION. THE GFS ON THE OTHER HAND REMAINS

MUCH SLOWER AND WOULD BRING SOME PRECIP TO EASTERN PORTIONS OF THE

CWA SATURDAY AFTERNOON INTO SATURDAY NIGHT. NOT SURPRISINGLY

CONSIDERING THE CUTOFF NATURE OF THE LOW...GFS ENSEMBLES SHOW MUCH

VARIATION IN THE TIMING/TRACK OF THE LOW AT THIS POINT. CONSIDERING

THE POOR DISAGREEMENT IN SOLUTIONS AT THIS TIME AND THAT THE FORECAST

AREA LOOKS TO BE ON THE WEST/NORTHWEST EDGE OF THE PRECIP THREAT AT

LEAST THROUGH SATURDAY AT THIS POINT...DECIDED TO KEEP POPS SILENT

BUT WILL NEED TO KEEP A CLOSE EYE ON THIS TIMEFRAME. ALTHOUGH BEYOND

THE RANGE OF THIS FORECAST...MODELS CONTINUE TO SUGGEST THE

POSSIBILITY OF ANOTHER DUMP OF ARCTIC AIR INTO THE PANHANDLES EARLY

THE FOLLOWING WEEK AROUND THE JAN 10 TIMEFRAME.

Norman, OK:

WHILE ALL THIS TRANSPIRES... LARGE-SCALE CHANGES WILL TAKE PLACE

ELSEWHERE THAT MAY MOVE THE PIECES INTO PLACE TO SET UP A PERIOD OF

MORE SIGNIFICANT WINTER WEATHER EARLY NEXT WEEK... AND POSSIBLY AS

EARLY AS NEXT SATURDAY. POSITIVE HEIGHT ANOMALIES OVER S GREENLAND

BUILD W ACROSS N CANADA WHILE NEGATIVE ANOMALIES DO LIKEWISE FARTHER

S NEAR THE LATITUDE OF THE US-CANADA BORDER. LATTER LEADS TO AN

UPPER LOW ANCHORING OVER THE WA/BC AREA BY NEXT WEEKEND... AND

STRENGTHENING OF THE WESTERLIES ACROSS THE CONUS. MEANWHILE AN UPPER

LOW DEVELOPS OFF THE S CA COAST... IN THE S PART OF THE

AFOREMENTIONED W-COAST SPLIT FLOW PATTERN. THIS SYSTEM WILL MOVE E

LATER IN THE WEEK BUT TIMING DIFFERENCES EXIST AMONG THE MED-RANGE

MODELS. THE STRONGER WESTERLIES BY THEN MIGHT GIVE A NOD TO THE

FASTER ECMWF... IN WHICH CASE PRECIP WOULD ARRIVE HERE BY NEXT

SATURDAY. LOW POPS ARE THUS BEING INTRODUCED NEXT WEEKEND.

THEN THERE IS THE ARCTIC AIR. MODELS CONTINUE TO BUILD A STRONG

HIGH-LATITUDE RIDGE AROUND 150-160W BY WEEKS END... WHICH IN TANDEM

WITH THE ABOVE-NORMAL HEIGHTS OVER N CANADA WILL SUPPORT A BUILDUP

OF COLD AIR OVER W CANADA BY NEXT WEEKEND. SOME OF THIS AIR WILL

OOZE/TRICKLE S INTO THE CENTRAL/EASTERN CONUS BY THE END OF THE

WEEK... LEADING TO A COOLING TREND FRIDAY AND BEYOND. IF ENOUGH OF

IT BECOMES ESTABLISHED THIS FAR S... WE COULD BE LOOKING AT A WINTER

PRECIP EVENT NEXT WEEKEND AS THE LATE-WEEK SYSTEM MOVES E ACROSS

TX/OK. MORE COLD AIR IS LIKELY TO MOVE S IN THE WAKE OF THIS

SYSTEM... AND THERE SHOULD BE PLENTY OF IT TO TAP INTO BY THEN TO

OUR N.

NOTE THAT BOTH THE 00Z GFS AND THE 00Z ECMWF HAVE A 500-MB HIGH OF

AROUND 580HPA OVER ALASKA BY TUE 11 JAN. NOT A GOOD SIGN - NASTY

THINGS USUALLY HAPPEN IN TERMS OF COLD AND SNOW/ICE IN PATTERNS LIKE

THIS... NOT ONLY AROUND HERE BUT IN MANY PARTS OF THE LOWER 48. NEXT

WEEK MAY BE INTERESTING IN A NUMBER OF WAYS.

Dodge City, KS:

NEXT WEEKEND THE PATTERN BECOMES A BIT MORE

INTERESTING AS BOTH 00Z GFS AND 00Z ECMWF INDICATE A FAIRLY STRONG

SHORTWAVE TROUGH MOVING ACROSS THE LONE STAR STATE. AS A RESULT,

HAVE INCREASED SILENT POPS IN THE GRIDS SATURDAY AND SUNDAY AND

LOWERED TEMPERATURES WITH ADDITIONAL CLOUD COVER EXPECTED. THE

ECMWF IS A BIT FASTER WITH THE UPPER AIR SYSTEM THAN COMPARED TO

THE GFS AND IT IS TOO SOON TO HAMMER OUT ALL THE DETAILS. THE

BOTTOM LINE IS THAT THERE PROBABLY IS A FAIR TO GOOD CHANCE AT

SEEING SOME FORM OF PRECIPITATION TOWARDS NEXT WEEKEND ACROSS

KANSAS.

JUST AS A SIDE NOTE, WEEK TWO LOOKS TO BE VERY INTERESTING ACROSS

THE PLAINS. THE GFS IS INDICATING A 1055-1060 (!) HPA HIGH SLIDING

DOWN THE LEE OF THE ROCKIES FROM NORTHERN CANADA. THE ECMWF IS

WEAKER (RELATIVELY SPEAKING - AROUND 1045 HPA) WITH THE HIGH AND THE

RESULTANT COLDER AIR SURGING DOWN THE PLAINS. ANYWAY, THERE ARE

SOME FAIRLY GOOD SIGNALS THAT TEMPERATURES WILL BECOME MUCH COLDER

AND FRIGID TOWARDS THE SECOND WEEK OF JANUARY. RIGHT NOW I AM

HEDGING TOWARDS THE FASTER GFS SINCE MODELS USUALLY HAVE A HARD TIME

BRINGING DOWN THE COLD ARCTIC AIR MASS WHEN IN REALITY THE ARCTIC

FRONT BEHAVES LIKE A DENSITY CURRENT AND GRAVITY TAKES OVER IN

BRINGING DOWN THE AIR MASS STRAIGHT SOUTH. THIS THINKING WAS CARRIED

TO THE GRIDS IN BRINGING DOWN TEMPS...PARTICULARLY TOWARDS THE END

OF THE EXTENDED PERIOD.

[Srain]

[Srain]

Stunning...

[wxmx]

Stunning...

Yeah...classic...Euro indicates the coldest airmass in our area in over 20 years probably...incredible that the GFS has a 1063mb and the Euro 1058mb at day 10 (and of course, the ridiculous 0z GGEM )

[Srain]

Yeah...classic...Euro indicates the coldest airmass in our area in over 20 years probably...incredible that the GFS has a 1063mb and the Euro 1058mb at day 10 (and of course, the ridiculous 0z GGEM )

Looks impressive, doesn't it Jorge? Been a long while since we have seen such strong signals of anything close to this magnitude of Vodka Cold. Perhaps a run at 83/89. Ahhh, the good old days of McFarland AFD's from KBRO

[Ed Lizard]

Marshall J Mcfarland and his famous paper...

500 mb map preceding doesn't exactly map the examples, but the 240 Euro and figure 5b bear a resemblance.

[Flexo]

From Norman:

MORE ATTENTION CONTINUES TO TURN TO THE POTENTIALLY SIGNIFICANT

TURN OF EVENTS NEXT WEEK. BIG RIDGE WILL BUILD N INTO ALASKA BY

LATE WEEKEND... SUPPORTING A SIZEABLE BUILDUP OF ARCTIC AIR OVER W

CANADA AND DOWNSTREAM HEIGHT FALLS INTO SW CANADA AND NW CONUS.

FORMATION OF A 500-MB 575-580 HIGH OVER AK... WHICH HAS BEEN

ADVERTIZED BY THE GFS AND ECMWF FOR SEVERAL DAYS NOW... GENERALLY

DOES NOT TURN OUT WELL - FOR MOST OF THE LOWER 48 MUCH LESS THE S

PLAINS. GFS SFC-T PROGS FOR NEXT TUESDAY ARE UNPRECEDENTED AS FAR

AS THIS FORECASTER CAN RECALL... AND IF TAKEN LITERALLY WOULD

IMPLY THAT PARTS OF MT/WY WOULD STRUGGLE TO REACH HIGHS OF -30F

NEXT TUESDAY. THAT SEEMS A WEE BIT EXTREME... BUT IN ANY EVENT THE

PATTERN CONTINUES TO SUGGEST A TURN TOWARD SIGNIFICANT AND

POTENTIALLY SEVERE WINTER WEATHER IN SOME WAY SHAPE OR FORM - THE

STUFF NATIONAL HEADLINES ARE MADE OF - BY SOMETIME NEXT WEEK.

COLD AIR IS LIKELY TO BEGIN INVADING THE PACNW AND NORTHERN

ROCKIES/HIGH PLAINS OVER THE WEEKEND AND ROLL SE THEREAFTER. AT

THIS TIME WE ARE LEANING TOWARD THE ECMWF AND A FASTER INVASION OF

ARCTIC AIR INTO THE S PLAINS NEXT SUNDAY NIGHT. WHAT HAPPENS AFTER

THAT IS HARD TO SAY. BITTER COLD... SNOW AND/OR ICE... OR PERHAPS

ALL OF THE ABOVE. SUFFICE TO SAY NEXT WEEK LOOKS TROUBLESOME.

Someone was excited...

Dallas also weighs in, big time:

/AND NOW A DISSERTATION ON A LIKELY COLD SPELL NEXT WEEK/

ALL THE MEDIUM TO LONG RANGE MODELS CONTINUE TO ADVERTISE A MAJOR

PATTERN SHIFT OCCURRING OVER THE NORTHERN LATITUDES...WITH BLOCKED

UPPER FLOW SETTING UP AND PERSISTING ACROSS CANADA. MODELS FORECAST

THE UPPER LEVEL RIDGE NOW OVER WESTERN CANADA TO BREAK DOWN AND BE

REPLACED BY A STATIONARY UPPER LEVEL LOW THIS WEEKEND. AS THIS

OCCURS...SURFACE TEMPS COOL AND PRESSURES GRADUALLY RISE. IN SHORT

THIS MEANS WESTERN CANADA WILL BE THE GENESIS REGION OF THE COLD

AIR MASS FORECAST TO ARRIVE IN 7 TO 8 DAYS.

THE ASTUTE OBSERVER WOULD NOTICE TEMPS ACROSS WESTERN CANADA AND

ALASKA ARE NOT THAT COLD NOW. I KNOW IT IS A HABIT FOR MANY OF US

TO THROW A MAP OF SURFACE TEMPS UP AND TRY TO SEE WHERE THE COLD

AIR IS AND WHERE IT IS COMING FROM. BUT THIS IS SORT OF A RULE OF

THUMB AND IS PARTIALLY FLAWED THINKING FOR A COUPLE REASON. FIRST

COLD AIR AT THE SURFACE IS NOT A CONSERVED QUANTITY...IT DEVELOPS

AND IS ALSO DESTROYED BY COMPLEX DYNAMIC MOTIONS ALOFT. THE SECOND

REASON IS AN ANALYSIS OF WHERE OUR PAST BIG ARCTIC OUTBREAKS

ORIGINATE USING BACKWARD TRAJECTORIES SHOWS US THAT THE NORTH POLE

REGION IS PREFERRED...BUT OUR SURFACE PARCELS HERE ACTUALLY

ORIGINATE AT LEVELS BETWEEN 500MB-700MB. THUS AN ANALYSIS OF

500MB-700MB TEMPS AND ANOMALIES IN THE NORTHERN LATITUDES CAN GIVE

US A GOOD PROXY TO COMPARE AND JUDGE THE STRENGTH OF FUTURE ARCTIC

EPISODES. THESE CURRENT MID-UPPER LEVEL TEMPS ARE CHILLY...BUT NOT

TOO UNUSUAL. SO THE FRONT THAT ARRIVES IN A WEEK MAY BE

SIGNIFICANT BUT NOT RECORD BREAKING...AT LEAST NOT INITIALLY.

WHAT IS INTERESTING ABOUT THE FORECAST UPPER PATTERN IS THAT BY

7-10 DAYS AN UNUSUALLY STRONG UPPER LEVEL HIGH IS FORECAST TO

DEVELOP OVER ALASKA...WITH A STRENGTHENING UPPER LOW ACROSS

NORTHERN CANADA. THESE POLAR LOWS ARE RESPONSIBLE FOR THE MAJOR

ARCTIC OUTBREAKS WHEN THEY MOVE SOUTH...AND THAT IS WHAT THE GFS

HAS BEEN FORECASTING TO OCCUR IN THE 10-15 DAY TIME RANGE. WHETHER

THIS ACTUALLY OCCURS REMAINS TO BE SEEN. REGARDLESS...THE BLOCKING

UPPER PATTERN WILL KEEP A PROLONGED FETCH OF CANADIAN/ARCTIC AIR

COMING INTO THE REGION FOR THE 2ND WEEK OF JANUARY. TOO EARLY TO

TELL WHETHER ANY MOISTURE WILL BE AVAILABLE...BUT NONETHELESS ITS

SHAPING UP TO BE AN INTERESTING WEEK WEATHER-WISE.

[Srain]

Here are other TX NWS snips and Dodge City, KS as well...

Amarillo:

THE ECMWF

IS ALSO MUCH COLDER THAN THE GFS BRINGING A STRONG COLD FRONT WITH

MUCH COLDER CANADIAN AIR BY EARLY NEXT WEEK. FAVOR THE COLDER ECMWF

SOLUTION LATE IN THE EXTENDED PERIOD INTO EARLY NEXT WEEK...WHILE

BOTH MODELS LOOK TO BE ON TRACK LATE THIS WEEK INTO THE WEEKEND.

San Angelo:

AT THE END OF THE FORECAST...IT APPEARS THAT THE INITIAL SURGE OF

MUCH COLDER/ARCTIC AIR WILL BE MAKING ITS WAY INTO THE AREA. HAVE

NOT COOLED TEMPERATURES OFF TOO MUCH AT THIS TIME AS THE COLDEST AIR

IS NOT EXPECTED UNTIL THE MIDDLE OF NEXT WEEK. HOWEVER...THIS

EVENT WILL BE SOMETHING TO WATCH AND KEEP TRACK OF IN THE COMING

WEEK.

Austin/San Antonio:

STARTING TO SEE INDICATIONS OF AN ARCTIC OUTBREAK EARLY NEXT

WEEK AND WILL CONTINUE TO MONITOR FOR RUN TO RUN CONSISTENCY. DID

NUDGE DOWN MIN TEMPERATURES A COUPLE CATEGORIES FOR MONDAY

NIGHT/TUESDAY MORNING...BUT STILL IN LINE WITH ADJACENT OFFICES.

Corpus Christi:

THE COLD AIR WILL REMAIN WELL TO THE NORTH OF THE AREA SUNDAY NIGHT.

HOWEVER...MODELS ARE INDICATING ARCTIC AIR PLUNGING INTO THE

NORTHERN PLAINS BY THE BEGINNING OF NEXT WEEK...WITH 1050MB PLUS

HIGH PRESSURE.

Lubbock:

JUST BEYOND...SOMEWHERE PERHAPS BETWEEN LATE NEXT SUNDAY AND MAYBE

TUESDAY APPEARS TO LOOM THE ARRIVAL OF A POLAR AIRMASS. UPPER

RIDGE BUILDING OVER THE NORTH PACIFIC INTO ALASKA SHOULD FAVOR

DELIVERY OF SUCH A SYSTEM...THOUGH TIMING DETAILS ARE UNCLEAR

RIGHT NOW.

Dodge City:

SUNDAY ONWARDS MARKS THE MOST INTERESTING SYNOPTIC CHANGE WITH

FRIGID WEATHER BECOMING MORE OF A CONCERN. OVER THE LAST DAY OR TWO,

THE MODELS HAVE BEEN GIVING NOT SO SUBTLE HINTS AT AN ARCTIC AIR

MASS INTRUSION ACROSS THE GREAT PLAINS. BY NEXT WEEKEND, BOTH THE

GFS AND ECMWF INDICATE A LARGE RIDGE WITH ANOMALOUSLY HIGH 500 HPA

HEIGHTS BUILDING OVER ALASKA. A LARGE POLAR VORTEX IS EXPECTED TO

REMAIN OVER EASTERN CANADA. THIS SYNOPTIC PATTERN FAVORS CROSS POLAR

FLOW AND A NORTH TO SOUTH FLOW ACROSS CANADA. THIS FLOW WILL BRING

MUCH COLDER AIR CLOSER (SURFACE FORECAST TEMPERATURES OF -10F TO

-30F). THIS AIR MASS WILL THEN HIT THE LEE OF THE ROCKIES AND THEN

GRAVITY WILL EVENTUALLY SEND THIS DENSE AIR MASS SOUTH INTO THE

UNITED STATES. THE MODELS DO NOT AGREE ON THE ARCTIC FRONT TIMING AS

NOW THE GFS IS SLOWER THEN ECMWF. I SIDED WITH THE FASTER SOLUTION

AND BROUGHT THE ARCTIC AIR IN BY NEXT SUNDAY. I HAVE MORE CONFIDENCE

ON THE DOWNWARD SPIRAL FOR TEMPERATURES BUT LESS ABOUT WINTRY

PRECIPITATION. AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE SOUTHERN

PLAINS SUNDAY AND IF THE ARCTIC TEMPERATURES DO VERIFY THEN THE

ATMOSPHERIC COLUMN WILL BE COLD ENOUGH FOR SNOW. THERE IS TOO MUCH

UNCERTAINTY SO I MADE MINOR TWEAKS TO THE EXTENDED PERIOD POPS. THE

BOTTOM LINE IS THERE IS A VERY GOOD CHANCE THAT IT WILL GET VERY

COLD AND REMAIN THAT WAY FOR A WHILE ACROSS SOUTHWESTERN KANSAS IN

ABOUT A WEEK FROM NOW.

[baroclinic_instability]

Looks impressive, doesn't it Jorge? Been a long while since we have seen such strong signals of anything close to this magnitude of Vodka Cold. Perhaps a run at 83/89. Ahhh, the good old days of McFarland AFD's from KBRO

I am excited about an arctic plunge. We have't had one for a good while. Also excited about chilling the vodka outside until it is a good and high viscosity consistency.

[Srain]

I am excited about an arctic plunge. We have't had one for a good while. Also excited about chilling the vodka outside until it is a good and high viscosity consistency.

It is exciting, but the flip side of that coin is what many here in our part of the world are not prepared for. Brief Arctic intrusions are handled rather well in our region. The longer more famous events of the past (83/89) created some major problems for our region. We are not accustom to that kind of cold in an agricultural and housing sense. There are other issues as well from an industrial standpoint. As you see by some of the wording for the NWS offices this morning, the word has officially began mentioning words such as historic and National Headline Cold, and rightly so. While we have been following the possibility of this event for a rather long time, the signals cannot be ignored and the waiting and soon to follow preparations will need to begin. What will be interesting is the potential long nature of this event and the reinforcing shot of brutally cold air will need to be closely monitored in the 10-15 day range. All in all, our pattern change shift began near Christmas Eve with a minor warm up this past week and beneficial rains for S Central/SE TX. That change looks to continue this week with even better chances of rain before our weekend event that will further set the stage toward the Arctic intrusion and reinforcing dump of that Vodka Cold. Our folks will likely be paying very close attention in the days ahead.

[baroclinic_instability]

It is exciting, but the flip side of that coin is what many here in our part of the world are not prepared for. Brief Arctic intrusions are handled rather well in our region. The longer more famous events of the past (83/89) created some major problems for our region. We are not accustom to that kind of cold in an agricultural and housing sense. There are other issues as well from an industrial standpoint. As you see by some of the wording for the NWS offices this morning, the word has officially began mentioning words such as historic and National Headline Cold, and rightly so. While we have been following the possibility of this event for a rather long time, the signals cannot be ignored and the waiting and soon to follow preparations will need to begin. What will be interesting is the potential long nature of this event and the reinforcing shot of brutally cold air will need to be closely monitored in the 10-15 day range. All in all, our pattern change shift began near Christmas Eve with a minor warm up this past week and beneficial rains for S Central/SE TX. That change looks to continue this week with even better chances of rain before our weekend event that will further set the stage toward the Arctic intrusion and reinforcing dump of that Vodka Cold. Our folks will likely be paying very close attention in the days ahead.

Yeah I understand, I didn't mean the post in a negative way. The societal impacts of weather are well known, and an arctic plunge in an area not accustomed to it is going to be high.

You make a good point, and what is another cold event to me is something which can have significant societal effects upon a region not prepared for it. Should this arctic outbreak verify all the way into the southern states, it will be interesting to note whether or not the somewhat significant lead time (up to 14 days) has much if any influence at all.

[Ed Lizard]

FWIW, the Euro cold shot at 240 looks to deflect somewhat East of Texas in 10days. But, the East-West alignment of the trough near the Canadian border looks somewhat like some of the 500 mb set-ups that preceded big McFarland outbreaks by a few days...

[Srain]

Yeah I understand, I didn't mean the post in a negative way. The societal impacts of weather are well known, and an arctic plunge in an area not accustomed to it is going to be high.

You make a good point, and what is another cold event to me is something which can have significant societal effects upon a region not prepared for it. Should this arctic outbreak verify all the way into the southern states, it will be interesting to note whether or not the somewhat significant lead time (up to 14 days) has much if any influence at all.

It does, particularly in the petrochemical and agricultural segment. Having experienced both 83 and 89 events as a professional fire fighter/OEM manager, the lead time does help from that standpoint. The average individual response would depend on how closely they follow weather via NWS or local/national venues of course and how that information is disseminated to the end user. Interesting times and welcome to our thread. Glad you are here and don't be a stranger.

[baroclinic_instability]

It does, particularly in the petrochemical and agricultural segment. Having experienced both 83 and 89 events as a professional fire fighter/OEM manager, the lead time does help from that standpoint. The average individual response would depend on how closely they follow weather via NWS or local/national venues of course and how that information is disseminated to the end user. Interesting times and welcome to our thread. Glad you are here and don't be a stranger.

Your weather knowledge is well noted, and you remind me of my favorite east coast poster A-L-E-X in terms of knowledge regarding weather history/events...you both definitely trump me.

Regarding lead time on weather events, there is definitely a lot of money/societal value in knowing potential impacts 2+ weeks in advance. A different topic for a different day perhaps, but dissemination of information, as you note, is a key driver in the push for changes in NWS protocol regarding both the dissemination of information as well as "impact forecasting". The NWS strategic plan is a worthwhile read regarding some of these possible future changes. http://www.weather.g...EPreview2-1.pdf

I will try and make my way down into the southern states more often. I have a number of friends down in Texas/OK, and my sister, until recently, was in MO. As a meteorologist, I probably know the least about southern climate/weather than any other region of the U.S., but I will make sure to head down in here more often to remedy that.

[Srain]

Here are some notable La Nina Winters of the past and could shed some light on what may be ahead as well as what has happened in the past regarding these type events via NWS Austin/San Antonio...

The averages do not pick up the extremes that have occurred since the Fall of 1949 and Winter of 1950. For South Central Texas, although on average moderate to strong La Nina conditions favor increasing probabilities of warmer and drier periods from the Fall through the Winter, there have been a few exceptions in the sub tropical climate over South Central Texas. Even though the active wintertime jet stream is displaced north of South Central Texas, there have been cases since the Fall of 1949 and Winter of 1950 where sub tropical weather patterns linked with features over the Tropics and Mid Latitudes to bring occasional cold outbreaks and periods of heavy rain and precipitation to South Central Texas. A few significant Arctic Outbreaks have come during La Nina Events, including December 1950; late January to February 1951; January and February 1985; February 1989; and January and February of 1996. Another feature that shows up with La Nina winters is more extremes between warm and cold, especially with the dry winters. February of 1996 was an extreme example where it was very cold at the beginning of the month, then set all time February Highs on February 21st, followed by very cold conditions at the end of February 1996. The February monthly record high at Del Rio of 99 on February 21, 1996 was later tied, when the high was 99 on February 25, 2008. The high on February 21, 1996 at Austin Mueller Airport was 99, at Austin Bergstrom 101, and at San Antonio 100 on February 21, 1996. The Winter of 1964/1965 had rainfall wetter than usual for Austin and San Antonio. The winter of 1967/1968 was wetter than usual at Austin, Del Rio, and San Antonio. In January 1968, a slow moving cutoff low came across the area from the west and caused a January flood, similar to the December 1991 floods. The January 1968 case occurred during a weak La Nina period, while the December of 1991 case occurred during a moderate to strong El Nino. January 1968 was the wettest January at San Antonio and the 4th wettest January at Austin Mabry. In November of 1974, during a La Nina period, a heavy rain event came to Austin, and caused flooding. From the Fall of 1984 through the Winter of 1985, during a La Nina period, wetter than usual conditions came most of the time, as relief from the dry period in 1984 came in the Fall of 1984. There were also a number of cold outbreaks in January and February of 1985. This included the heavy snow event that came in January 1985, a record for San Antonio and Del Rio and the 7th heaviest snow for Austin. In January 1985 the first snow event came January 2nd followed by a 2nd snow event from January 11th to 13th, 1985. January 1985 holds the record for the most snow in a month at San Antonio, 15.9 inches of snow, and at Del Rio, with 9.8 inches of snow. For snowfall at Austin January 1985 comes in 2nd place with 7.5 inches of snow, after the record of 9.7 inches of snow in January 1937. Floods from a heavy rain event in October 1998 during La Nina were followed by very dry conditions from December 1998 through the Winter of 1999. In the La Nina period from the Fall of 2000 through the Spring of 2001, wetter than usual conditions came, accompanied by occasional cold outbreaks.

http://www.srh.noaa.gov/images/ewx/wxevent/laninascntrltx.pdf

[Srain]

The 12Z GFS continues the trend and depicts a 1062 mb Arctic High in Western Canada...

[Srain]

The 12Z GFS also suggests a storm taking shape to our SW/W in the 240 hour time frame. With all the cold air in place via the GFS at that time, wintry weather breaks out and spreads across the Lone Star State.

[wxmx]

The 12Z GFS continues the trend and depicts a 1062 mb Arctic High in Western Canada...

1065mb

Also, the configuration of the 500mb pattern is also exceptional, since there's more support for the West coast ridging "phasing" (connecting) with the EPO ridge...although not shown yet by the models, that could bring the holy grail of polar/STJ longwave phasing well south. Still, it shows a pattern that's good for overrunning for far S and SE TX. Also of note, is that the models are faster with the dense airmass coming south (Dec 11th) vs previous run, and they are agreeing in that it would be at least a 2 step cold shot, which means a long duration event.

[Srain]

Getting very hard to ingnore, Jorge. If this comes to pass we'll likely see an event that could rival the 85 record regarding snowfall potential for S Central TX.

[Scott747]

Someone PM me when there is a 1055 high over the Rockies and some overrunning moisture.

Otherwise Tahoe beckons.

[Srain]

Someone PM me when there is a 1055 high over the Rockies and some overrunning moisture.

Otherwise Tahoe beckons.

Have fun Scott. See ya soon.

[Flexo]

Someone PM me when there is a 1055 high over the Rockies and some overrunning moisture.

Otherwise Tahoe beckons.

I'll do it

[Scott747]

I'll do it

This might just be a decent event. Texas winter weather (and specifically SE Texas) is lacking. Just hard to get into it and it takes quite a bit before I consider it significant. Potential is there but as per the norm I don't know how many times in the past we have seen the 'potential' to have a large and deep Arctic airmass come our way.

Chatter is definitely out there....

[wxmx]

The Euro ups the ante...1069mb...just like our childhood cartoons...both the NAO and EPO ridge fuse to form the MEGABLOCK!

[wxmx]

Almost -8°C 850mb around here? Wow! I have not had any < 32F this year ... and 10 day Euro still shows a -EPO ridge and a 1050+mb building up north

[Srain]

Just stunning to see the consistency at this range.

[Scott747]

King Euro let me down a few times this tropical season.

I can't even see the Caribbean on that map.

[wxmx]

Just stunning to see the consistency at this range.

Yes, it would be a huge letdown if this doesn't pan out...and by that I mean that 0°C for MBY doesn't cut it. But usually huge events, the ones that "make national headlines" are well modeled far away in time by models.

[wxmx]

King Euro let me down a few times this tropical season.

I can't even see the Caribbean on that map.

I hear you, though it didn't let me down as much as it did to you. OT, developing/strengthening moderate/strong Niñas aren't usually that good for the W GOM tropical landfalls, other than deep S TX and MX.

[BikiniBottom]

Someone PM me when there is a 1055 high over the Rockies and some overrunning moisture.

Otherwise Tahoe beckons.

Yeah, it seems '83 and '89 get mentioned every year, and then the threat decreases. I guess one of these days it will happen and who knows... maybe this is it. The models do look insanely cold.