Texas winter wx thread (2009-2010)

[Ntxw]

Well for thoughts, the 0z tonight continues the southern push of the storm.

[iorange55]

Well for thoughts, the 0z tonight continues the southern push of the storm.

It looks more interesting than the 18z run, but still it's not showing any big winter storm yet, at least for the Texas area. But I guess as far as trends go it trended in the right direction.

[iorange55]

Well the trends have gone in our favor, and now the DFW NWS has mentioned there could be a few flurries in the North East part of North Central Texas, and we'll have to watch it. Which is a turn around from yesterday, and Oklahoma City's NWS is saying accumulating snow or ice is likely for them, but most will be north, and east. Which is a turn around from Yesterday.



But it still looks like the low is too far north and east even after the models showing it further south now, so this kind of makes me more upset that instead of no chance, it might be one of those just barely missing out which would suck even more. I hope the track moves further south, we'll see.

[srainhoutx]

HPC early thoughts this morning...keep in mind the 500mb Upper Low is further S and W which is causing the changes you are reading in AFD's...the EC wants to hold back things just a bit and expect more changes with future guidance from WFO's across TX..

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
146 AM EST SAT DEC 19 2009

VALID 12Z WED DEC 23 2009 - 12Z SAT DEC 26 2009


OVETHE DETERMINISTIC MODELS ARE TRENDING AWAY FROM THE IDEA OF A
DEVELOPED SYSTEM R THE GREAT LAKES DURING THE MEDIUM RANGE
PERIOD...WHICH FITS THE STRONG NEGATIVE NAO PATTERN IN PLACE
ACROSS EASTERN CANADA. USED THE MOST SUPPRESSED GUIDANCE
AVAILABLE WITH THIS PATTERN IN MIND...WHICH WAS A BLEND OF THE
12Z/18 EC ENSEMBLE MEAN AND 18Z/18 GEFS MEAN...TO CONSTRUCT THE
PRELIMINARY FRONTS AND PRESSURES FOR DAYS 3 THROUGH 7. BOTH THE
EC ENSEMBLE MEAN AND GEFS MEAN HAVE OUTPERFORMED THE DETERMINISTIC
MODELS BY A NOT INSIGNIFICANT MARGIN DURING THE LAST FOUR MONTHS.
WOULD NOT BE SURPRISED TO SEE FUTURE MODEL RUNS THAT ARE EVEN MORE
SUPPRESSED THAN THE MANUAL BLEND CHOSEN FOR THIS FORECAST
PACKAGE...A SIGNIFICANT FACTOR IN HOW MUCH PRECIPITATION FALLS AS
SNOW BY CHRISTMAS EVE AND CHRISTMAS ACROSS THE MIDWEST AND EASTERN
STATES.

CISCO

Dodge City, KS gives the best "play by play" analysis of the 00Z's...

DAYS 3-7...

THE MAGNITUDE OF THE MID-WEEK WINTER STORM IS COMING INTO A BIT
BETTER FOCUS: A SIGNIFICANT SNOW AND WIND EVENT APPEARS LIKELY
ACROSS PORTIONS OF THE WESTERN PLAINS...INCLUDING SOUTHWEST KANSAS.
WITH THAT SAID...THERE ARE STILL MAJOR QUESTIONS REGARDING WHEN AND
WHERE THE MAJOR CYCLOGENESIS EVENT OCCURS...AND IT ALL REALLY BEGINS
WITH HOW THE MODELS HANDLE THE UPSTREAM RIDGE AMPLIFICATION AND
DOWNSTREAM ORIENTATION OF THE DIGGING JET/PV STREAM ACROSS THE
WESTERN CONUS.

THE ECMWF AND GFS DETERMINISTIC SOLUTIONS HAVE DIFFERENT IDEAS ON
HOW TO HANDLE THE DOWNSTREAM DEVELOPMENT OVER THE WESTERN/CENTRAL
CONUS. THE DIFFERENCES BEGIN TO APPEAR AROUND F72 (00Z TUES) AND
BECOME EVEN MORE EVIDENT AROUND F84 WITH THE RIDGE AROUND 135W
LONGITUDE. THE ECWMF MAINTAINS A MUCH MORE CLASSIC, SHARP RIDGE
AXIS NOSING WELL UP INTO SOUTHEAST ALASKA. THE GFS PINCHES OFF THE
RIDGE WITH POLAR JET FLOW CUTTING THROUGH THE SHARP
RIDGE...EFFECTIVELY ESTABLISHING A NEW, BROADER, LESS AMPLIFIED
RIDGE BY F96 OFF THE PACIFIC NORTHWEST COAST. AT F96...THE ECMWF
MAINTAINS A FULL LATITUDE RIDGE WITH ESSENTIALLY NO SIGNIFICANT JET
ENERGY CUTTING ACROSS THE RIDGE. WHAT THE ECMWF IS IN FACT DOING IS
BUILDING THE RIDGE UP SO MUCH...WHILE NOT PINCHING IT OFF...THAT IT
IS TAPPING INTO THE HIGH-PV RESERVOIR THAT AWAITS ACROSS WESTERN
CANADA TO BE TRANSPORTED EQUATORWARD. THIS IS WHY THE ECMWF HAS NOW
TRANSFORMED INTO A MUCH MORE IMPRESSIVE SOUTHWEST CONUS 500MB
DEVELOPMENT BY F108 (12Z WED)...WHILE THE GFS AND CANADIAN GEM STILL
MAINTAIN THE "FLATTER" PV INTRUSION INTO THE GREAT PLAINS...WITH
CYCLOGENESIS OCCURRING FARTHER EAST AND NOTABLY SOONER.

EITHER WAY...A MAJOR WINTER CYCLONE WILL FORM AND BOTH SOLUTIONS
IMPACT SOUTHWEST KANSAS WITH SNOW AND WIND ON SOME LEVEL. THE ECMWF
SOLUTION IS JUST A HIGHER-IMPACT SOLUTION FOR SOUTHWEST KANSAS...SO
MUCH SO THAT IT IS ESSENTIALLY DEPICTING A FULL-BLOWN BLIZZARD
WEDNESDAY INTO THURSDAY. WHENEVER THE SIGNIFICANT, DEEP
TROPOSPHERIC CYCLOGENESIS DOES OCCURS...IT APPEARS LIKELY THAT AT
LEAST NEAR BLIZZARD CONDITIONS WILL OCCUR TO THE NORTHWEST OF WHERE
THIS HAPPENS.

IN THE GRIDS...HAVE NOT MADE MUCH CHANGE OTHER THAN INCREASE WINDS
WEDNESDAY AND THURSDAY...AS WELL AS EXTENDING SOME 20-30 POPS INTO
THURSDAY. WILL BEGIN TO ENHANCE THE WORDING JUST A LITTLE BIT MORE
IN THE MORNING HWO REGARDING THIS EVENT...WITH THE FOCUS BEING
SIGNIFICANT SNOW PLUS WIND TO THE POINT OF PERHAPS BLIZZARD
CONDITIONS IMPACTING WESTERN KANSAS. -UMSCHEID

[Portastorm]

The 0z Euro definitely continues the "trend" it showed in yesterday's 12z run of moisture remaining over regions of far north Texas. It also looks very cold over all of Texas for later next week. The Euro, in fact, looks colder than the 0z GFS. That being said, if this were to verify ... places like Amarillo-Wichita Falls-Denton-Texarkana ... might see some snow in or around Christmas.

http://www.meteo.psu.edu/~gadomski/ECMWF_0z/ecmwfloop.html

Meanwhile and until later next week, we can all live vicariously through our friends on the East Coast who appear to be getting hammered today by a major snowstorm.

[Portastorm]

And FWIW with relevance to my own neck of the woods, I believe the NWSFO Austin/San Antonio is woefully handling temperatures for Christmas Day here. They currently predict highs in the low 50s with sun. My bet is the actual highs won't get above the mid 40s with sun. They'll have to lower those predicted highs several categories like they've had to do several times already this season.

[gboudx]

as of rightnow i would say on a line from central,wrn missouri into far w,nw arkansas back into ern oklahoma down to around the dallas-fortworth metroplex and points westward including most all of oklahoma, northern, northwestern tx the oklahoma & tx panhandles up into kansas, portions of colorado & new mexico i believe
firmly this 'FUZZY' picture that most are so darn confused about at this point is fixing to become alot clearer my friends in that area i just discribed i feel strongly we will see a *MAJOR* winter storm start to take shape as we head into wednesday - christmas day, accumulations we likely be on the high side we wont even go there rightnow just say an average of above 3-4 inches in most areas, areas of almost blizzard conditions on christmas eve with north winds blowing along and behind the front at near 30-40 mph... ***ANYONE WITH PLANS TO TRAVEL DO NOT LET YOUR GUARD DOWN, IAM NOT TRYING TO 'HYPE' THIS OR MAKE THIS A BIGGER DEAL THEN IT IS, THIS HAS THE CHANCE TO BE A MAJOR, MAJOR WINTER STORM EFFECTING A LARGE PORTION OF THE SOUTHERN PLAINS HEADING INTO CHRISTMAS... i will post more over the weekend but i feel strongly this is the most likely outcome of events next week, we will see in the coming days......


EDIT: I would just strongly advise anyone at this point the gfs is MUTE, it has failed us on alot so far, i have my faith, trust in the euro
and we will see but the signs are there if you look @ the upper flow pattern what the gfs is putting out on temps isnt always as we talked
yesterday the place to look for clues... so just everyone hang tight through the weekend becouse i can almost promise we are in for one
hell of a ride next week if you live in n.tx into oklahoma and the other areas mentioned


EDIT 2: ALSO would add this is my own forecast, judgement and is in no way endorsed by storm2k.org
i would simply advise people to watch your local weather on tv and or radio or a noaa weather radio
for the very latest in your area.

With respect to Edit 2, you're making quite a bold prediction for the Christmas Eve/Christmas timeframe. You're the only one I see making this type of prediction. I read Edit 1, but not quite clear on why you feel part of NTX/OK could have a major, major winter storm. Can you elaborate more?

[srainhoutx]

Here is the "detailed" HPC Morning Prelim Extended... and as Portastorm mentioned we can look see our neighbors to the E have a mess on their hands and even the HPC mentions it...

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
845 AM EST SAT DEC 19 2009

VALID 12Z WED DEC 23 2009 - 12Z SAT DEC 26 2009

MODELS AND ENSEMBLES SHOW QUITE AN ACTIVE FLOW PATTERN ALOFT THAT
BY MIDWEEK IS PRIMARILY COMPRISED OF AN AMPLIFIED WEST-CENTRAL US
TROUGH SANDWICHED BETWEEN AMPLIFIED NOAM WEST COAST AND SERN US
RIDGES...ALL LEADING INTO ERN CANADIAN/GREENLAND BLOCKING WITH
TROUGHING HELD DOWN OVER THE NERN US. THIS PATTERN MANAGES TO BE
SLOWLY PROGRESSIVE ALOFT WITH THE HIGHLY AMPLIFIED WEST-CENTRAL
TROUGHING SPREADING ACROSS THE EAST-CENTRAL US INTO LATE
WEEK...EVEN AS HEIGHT FALLS HOLD/DIG BACK TO VARIOUS DEGREES INTO
THE WEST-CENTRAL US TO THE LEE OF THE PERSISTENT NOAM AMERICAN
WEST COAST RIDGE. HPC PROGS DEPICT A WEST-CENTRAL US 500 MB HEIGHT
FIELD ALOFT THAT IS MOST IN LINE WITH THE 00 UTC GFS ENSEMBLE MEAN
THAT LIES IN THE MIDDLE OF THE FULL SOLUTION ENVELOPE.

DETERMINISTIC MODELS ARE STILL SHOWING AMPLE RUN TO RUN CONTINUITY
ISSUES DOWNSTREAM...BUT WITH THE MOST NOTABLE EXCEPTION OF THE 00
UTC ECMWF...ARE OVERALL TRENDING AWAY FROM THE IDEA OF SUCH A
HIGHLY DEVELOPED PARENT SYSTEM HEADING FROM THE SOUTH-CENTRAL
PLAINS NEWD TO THE GREAT LAKES MID-LATE WEEK. EVEN A WEAKER SYSTEM
WOULD FOCUS SIGNIFICANT WINTER WEATHER WITH
INFLOW/CONVERGENCE/LIFT...BUT THIS GUIDANCE TREND FAVORS THE
TRANSFER OF MORE ENERGY AND WEATHER FOCUS INTO EAST-CENTRAL US
TRIPLE POINT LOW DEVELOPMENT THEN ERN SEABOARD CYCLOGENESIS
HEADING THROUGH CHRISTMAS EVE/CHRISTMAS AND INTO NEXT WEEKEND.
THIS SOLUTION SEEMS A BETTER FIT WITH THE STRONG NEGATIVE NAO
PATTERN IN PLACE ACROSS ERN CANADA THAT TEND TO MAINTAIN STRENGTH
LINGER THAN GUIDANCE INDICATES...BUT REMAINS IN BATTLE WITH POTENT
SE US MID-UPPER LEVEL RIDGING WHOSE PERSISTENCE DOES NOT YET
PRECLUDE AN ALTERNATE SOLUTION MORE IN LINE WITH THE DOWNPLAYED 00
UTC ECMWF IN A DATA SENSITIVE FLOW REGIME.

ACCORDINGLY...UPDATED HPC PRELIM MEDIUM RANGE GUIDANCE IS NOW
PRIMARILY BASED FROM ONE OF THE MORE SUPPRESSED GUIDANCE SOLUTIONS
WITH THIS PATTERN IN MIND...SIMPLY THE 00Z GFS ENSEMBLE MEAN.
THIS MAINTAINS CLOSE HPC CONTINUITY AMID GREATER THAN NORMAL
UNCERTAINTY IN A STORMY WINTER HOLIDAY PATTERN. ENSEMBLE MEANS
MEAN HAVE OVERALL OUTPERFORMED THE DETERMINISTIC MODELS BY A NOT
INSIGNIFICANT MARGIN DURING THE LAST FOUR MONTHS AT THESE TIME
FRAMES AND HAVE BY AVERAGED NATURE SHOWED BETTER RUN TO RUN
CONTINUITY. FYI...WE HAVE ALOT OF SNOW HERE TODAY AT HPC OUTSIDE
DC AND AWAIT WHATEVER THIS ACTIVE WINTER SEASON BRINGS US.
CISCO/SCHICHTEL

[gofrogs]

Actually the dfw AFD just basiclally said that if the trend keeps treniding south that we could see a significant winter storm mainly north of I 20.

[Portastorm]

Actually the dfw AFD just basiclally said that if the trend keeps treniding south that we could see a significant winter storm mainly north of I 20.

Not quite ... the AFD said the forecast could change regarding snow. I didn't see any mention of "significant winter storm."

It definitely gives us something to watch though this weekend to see how the models trend re: the system.

[Ntxw]

Believe it or not, it's still yet way too early =P but gofrogs is right they did leave an open window.

Edit: Portastorm is underplaying this, meaning we'll get something big! Jk

[weatherguy425]

DFW NWS...

FOR LATE WEEK AND THE HOLIDAY...A VERY CHILLY FORECAST STILL APPEARS
IN THE OFFING...BUT LIKELY NOT A WHITE ONE FOR NORTH TEXANS. LATEST
00Z ECMWF RUN HAS BECOME MORE PROGRESSIVE AND NORTH WITH THE SYSTEM
TRACK ACROSS OK/AR DURING THE HOLIDAY TIME FRAME. THIS IS IN LINE
WITH THE GFS THINKING THE PAST SEVERAL DAYS. 850-700 MB RH FORECASTS
AND MODEL SOUNDINGS INDICATE TOP-DOWN DRYING WITH ONLY SHALLOW LOW
LEVEL MOISTURE ACROSS NRN NORTH TEXAS BY THE TIME THE ARCTIC AIR
ARRIVES...AS EVEN THE ECMWF INDICATES A DRY SLOT ARRIVING FROM THE
SSW...LIKELY BRINGING MODIFIED/STABLE/DRIER AIRMASS FROM THE SIERRA
MADRE RANGE IN NRN MEXICO.

[gofrogs]

I think thats old.

[gofrogs]

Nm but they did leave the4 window wide open.

[weatherguy425]

While furries and light snow is still **possible**, any significant accumulations would most likely occur in N OK and Kansas... at least right now.

[iorange55]

I think thats old.

No it's from this morning, just remember sometimes you gotta look at the models, and be realistic not think with your heart. It could change, of course. But as of right now the chance of a winter storm here in North Texas next week aren't that high, and that's not underplaying it that's looking at the current situation, and reading the models. I hope with all my heart it changes, but right now there is not a good chance of it happening.

[srainhoutx]

Look for trends folks. Remember how the past systems have played out so far this Fall/Winter Season. Just keep in mind the "stepping down" process that we have discussed.

[cheezyWXguy]

I think this is the part of the discussion gofrogs was referring to:

Have added low chances of light rain across the NE counties Wednesday
night just behind the front...but with temperatures still above freezing.
Can't rule out a few flurries in wrap-around/shallow stratus near
the Red River valley Christmas evening...as upper low lifts eastward across
the Ozarks and into the lower MS valley. Currently...this pattern
doesnt Bode well for a significant winter weather event across
North Texas if medium range model trends continue 'as is'. However
..if future runs bring upper low track further south...Then the
forecast could change regarding snow...mainly north of I-20. A few
logs will definitely need to be thrown on the fire when opening
presents this Holiday season.

And this does suggest that if models continue to trend further south, a larger winter weather event is more possible.

[Portastorm]

The 12z GFS is rolling and at 120 hours it has the low pressure on Christmas Eve further northwest than the 0z run. This is more in line with what the 0z Euro showed.

Edit Update: Based on the last two GFS runs, I'd say folks in the southwestern half of Oklahoma have a decent shot at a White Christmas.

[srainhoutx]

The 12z GFS is rolling and at 120 hours it has the low pressure on Christmas Eve further northwest than the 0z run. This is more in line with what the 0z Euro showed.

Also noticed a very persistent stormy/chilly pattern setting up behind the Pre Christmas Storm. The door is opening for what will likely be a very interesting period through the New Years time frame. Stepping Down...