Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 3

[wxmx]

The Canadian and Euro budged and the GFS is a little slower with the Pacific energy which is currently digging south, making a pretty nice consensus with the abandonment of the off the SW coast cutoff low, and swinging the trough over the Rockies and Plains. This is a much colder solution, which will probably sag the 0C 850 mb pretty far south and across most of TX and even MBY. Winter storm for a good deal of W, N and C TX probably. Parts of N Mex, N TX and OK might see <-10C 850mb temps

[Srain]

The Canadian and Euro budged and the GFS is a little slower with the Pacific energy which is currently digging south, making a pretty nice consensus with the abandonment of the off the SW coast cutoff low, and swinging the trough over the Rockies and Plains. This is a much colder solution, which will probably sag the 0C 850 mb pretty far south and across most of TX and even MBY. Winter storm for a good deal of W, N and C TX probably. Parts of N Mex, N TX and OK might see <-10C 850mb temps

Nice to see you warm up to that idea I mentioned to you a while back...

[Srain]

The overnight guidance has trended a bit colder and suggests a freeze is likely next Monday night/Tuesday morning. There still remain some wrinkles to iron out, but light rain chances beginning as early as Thursday night through Friday and into the weekend appear to be in the works. It still looks as if we could see some over running light precip behind the front as the second upper air disturbance begins to eject E from Arizona. There is a chance that parts of Central and N Texas may need to keep an eye out for some possible very light wintry mischief behind that strong front on Sunday night into Monday morning and possibly extending into Monday night. We will see. This is still an evolving situation and caution is advised and the forecast is subject to changes over the next several days. Stay tuned, as they say...

[#NoPoles]

things look to be getting interesting for Albuquerque area...Santa Ana wind event followed by accumulating snow...in a Nina year...weird weird Nina pattern...

[Srain]

The 12Z Euro continues to advertise a 1-2 punch of upper air disturbances ejecting out of Arizona. The overall trend has been a NAM GFS camp ~vs~ Euro/Canadian/UKMET solution regarding the timing and strength of these upper air features. The Euro scores better than the GFS, so credence is given to its solution by many when forecasting. It does appear some very chilly air will settle S behind the modified Arctic boundary with some over running light precip until the second disturbance ejects E across N MX into the S Plains. Of note is wintry weather is looking more likely for parts of W TX and the Panhandle with both disturbance. Freezing rain mixed with some snow with the first system and the stronger second disturbance could bring snow showers across those regions. Further S it appears that nothing but a chilly drizzle/light rain with the upper flow out of the SW until the second 500mb disturbance/trough sweeps E ending the precip and setting the stage for some rather cold nights early next week.

[wxmx]

Latest Euro drops measurable snow in the mountains to my S and W next Tue morning, with even some light snow in the extreme S and W of the metro area. That would mark the earliest snowfall recorded for my area if it verifies. It almost never does, so I keep my expectations very low.

[Msalgado]

Peak gusts here in Albuquerque so far are in the 70-75 mph range but that may grow as the afternoon goes on. The dynamics behind this are not a normal canyon/gap wind scenario as its actually coming over the Sandias to the east and not only the canyons. Definitely a great day to be a weather geek here. The commute home tonight to Santa Fe should be fairly interesting and the snow tomorrow should be good as well.

Thank goodness for this storm because the flat out boring nature of fall here was starting to kill me.

[Quixotic1]

NWS issued Freezing Rain Advisory for parts of the LLano Estacado. Color scheme fooled me into a WSW. LOL.

[Srain]

An interesting discussion from Corpus Christi this afternoon:

WHILE COLDER AIR ENTERS THE CWA/MSA SUNDAY

NIGHT/MONDAY...ISENTROPIC LIFT CONTINUES (THE UPPER LOW/TROUGH AXIS

STILL TO THE WEST) AND THUS WILL MAINTAIN LIGHT RAIN SHOWER ACTIVITY

THROUGH MONDAY. MONDAY NIGHT/EARLY TUESDAY...LIGHT RAIN/SHOWERS

LIKELY TO PERSIST BASED ON GFS ISENTROPIC LIFT/LOW CONDENSATION

PRESSURE DEFICITS AT 300K...YET GRADUALLY DECREASE FROM WEST TO

EAST. RECALL HWR THAT THE GFS IS FASTER. THE SLOWER ECMWF SUGGEST

PCPN THROUGH TUESDAY. HWR WILL FCST THE PCPN TO END OVER THE CWA BY

12Z TUESDAY. THE GFS PROGS 06-12Z TUESDAY 1000-850MB AND 850-700MB

THICKNESS VALUES CLOSE TO A FREEZING RAIN SCENARIO...ESPECIALLY OVER

THE CNTRL/WRN CWA. WL FCST MIN TEMPS TUESDAY IN THE MID/UPPER 30S

HWR WET BULB TEMPS MAY CONTRIBUTE TO A BRIEF PERIOD OF ICE PELLETS.

THE CONFIDENCE IN FREEZING/FROZEN PCPN IS VERY LOW AT THIS TIME AND

THUS WILL NOT FCST SUCH.

edit to add a snip from Norman:

AS COLD AIRMASS SETTLES SOUTH OVER THE AREA SUNDAY NIGHT INTO MONDAY

MAIN UPPER TROUGH BEGINS TO SHEAR OUT AND MOVE EAST OVER THE

SOUTHERN PLAINS. THIS MIGHT PRODUCE SOME VERY LIGHT SNOW FLURRIES

ACROSS MAINLY SOUTHERN OKLAHOMA INTO NORTH TEXAS MONDAY/MONDAY

NIGHT... SO HAVE LEFT A MENTION OF THIS POSSIBILITY IN THE FORECAST.

Add San Angelo to the mix:

FROM SUNDAY INTO MONDAY NIGHT...THE UPPER LEVEL TROUGH HAS A HARD

TIME MAKING PROGRESS TO THE EAST...SO WE WILL HAVE LINGERING

SLIGHT CHANCE POPS...ESPECIALLY FOR SOUTHEASTERN AREAS WHERE MORE

MOISTURE IS AVAILABLE. HOWEVER...THE PROBLEM WITH THE

PRECIPITATION IS THAT TEMPERATURES WILL BE COLD ENOUGH BEHIND THIS

COLD FRONT BY SUNDAY NIGHT THAT A RAIN/SNOW MIX OR SNOW WILL BE

POSSIBLE ACROSS THE CWA. WILL KEEP A LINGERING CHANCE FOR FLURRIES

INTO MONDAY AS THE LOW FINALLY BEGINS TO MOVE AWAY FROM THE AREA.

THE COLDEST AIR OF THE SEASON IS EXPECTED FOR MONDAY AS COLD AIR

ADVECTION IS REINFORCED BEHIND THE TROUGH MONDAY...WITH

TEMPERATURES HAVING A HARD TIME MAKING IT OUT OF THE

30S...ESPECIALLY IF ANY PRECIPITATION OCCURS.

Also add Houston/Galveston in the interesting catagory:

THE STRONG UPPER LEVEL LOW PRESSURE SYSTEM RESPONSIBLE FOR THE

STRONG WINDS ACROSS SOUTHERN CALIFORNIA WILL BEGIN TO WEAKEN AND

MOVE EASTWARD BY SATURDAY. AS THE UPPER LOW APPROACHES THE REGION

IT WILL PUSH THE COLD FRONT SOUTHWARD THROUGH OUR REGION SUNDAY

MORNING. SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG AND AHEAD OF

THE FRONT AND STRONG ISENTROPIC LIFT IN THE WAKE OF THIS FRONT

WILL ALLOW FOR WIDESPREAD LIGHT RAIN THROUGH THE DAY SUNDAY AND

MONDAY WITH MUCH CHILLIER CONDITIONS EXPECTED. THE RAIN SHOULD

TAPER OFF MONDAY NIGHT INTO TUESDAY AS COOLER AIR MOVES INTO THE

REGION. AT THIS TIME IT APPEARS THAT THE RAIN WILL MOVE OUT OF THE

REGION BEFORE THE TEMPERATURE PROFILE WOULD BE SUPPORTIVE OF ANY

WINTRY PRECIPITATION...ALTHOUGH A FEW MODELS SUGGEST THAT THERE

COULD BE A BRIEF PERIOD OF MIXED PRECIPITATION ACROSS OUR FAR

NORTHERN COUNTIES. GIVEN THAT THIS IS A LOW PROBABILITY OUTCOME

AND FAIRLY FAR INTO THE FORECAST PERIOD IT WILL NOT BE REFLECTED

IN THE CURRENT FORECAST PACKAGE.

[#NoPoles]

just heard on my local news that Vegas got 6inches of snow...totally the wrong thread for Vegas wx talk...but i didn't know where to go to post about it...

[baroclinic_instability]

just heard on my local news that Vegas got 6inches of snow...totally the wrong thread for Vegas wx talk...but i didn't know where to go to post about it...

We are still trying to figure out good bounds. I would post any mountain related disco in the "Mountain W" thread.

[#NoPoles]

We are still trying to figure out good bounds. I would post any mountain related disco in the "Mountain W" thread.

well, technically you could have a desert southwest/plateau thread...that's what i was looking for to post about Vegas

[baroclinic_instability]

well, technically you could have a desert southwest/plateau thread...that's what i was looking for to post about Vegas

That is an idea. See if Srain likes that too, but I don't mind breaking it down like that.

[Srain]

That is an idea. See if Srain likes that too, but I don't mind breaking it down like that.

I see no problem with breaking things down. I believe the 'goal' is to grow our Region and if that would help and add participation, I say go for it...

[Srain]

The change via overnight guidance is to slow the ending of precip on Tuesday. The HPC is suggesting a Euro/GFS ensemble blend with a slight slowing of the ejection of the upper air distubance in the SW on Sunday night into Monday. Cold temps and light over running precip still look likely before clearing out possibly as late as Tuesday afternoon. Nasty cold/raw weather ahead from Sunday night until everything shifts E. The early morning chatter with the NWS offices is to include possible wintry mischief, mainly to our N and W. There remains a lot of uncertainty, so further 'fine tuning' can be expected...

[Srain]

The 06Z GFS has trended slightly slower with the Upper Air features in the SW as well as the northern stream. That model run has also come in a bit 'cooler' behind the front. This trend would tend to be more in line with what the Euro has shown. That said, this is still a very complicated and volatile forecasting challenge, so expect further adjusting as the weekend evolves. The concern in the near term is heavy rainfall chances. This will need to be monitored throughout the weekend as we see just how this all plays out. Some much for boring hot and dry weather...

PRELIMINARY EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

742 AM EST FRI DEC 02 2011

VALID 12Z TUE DEC 06 2011 - 12Z FRI DEC 09 2011

A DEEPENING/BROADENING MID-UPPER LEVEL TROF ACROSS CANADA INTO THE

CONUS IS FORECAST TO EJECT AN ELONGATED MEAN TROF INITIALLY

EXPECTED TO EXTEND FROM HUDSON BAY SWWD INTO THE SWRN CONUS. THE

EXACT DETAILS OF HOW ENERGY WITHIN THE LEADING TROF WILL EVOLVE AS

IT CROSSES THE LOWER 48 WILL LIKELY TAKE SOME TIME TO BE RESOLVED

GIVEN CURRENT GUIDANCE SPREAD AND RECENT CONTINUITY CHANGES. THE

BEST CLUSTERING OF SOLUTIONS LIES WITH THE 00Z

ECMWF/UKMET/CMC/ECMWF ENSEMBLE MEAN AND TO A LESSER EXTENT THE GFS

ENSEMBLE MEAN WHICH ARE ALL SLOWER THAN THE 00/06Z GFS RUNS.

THESE GFS RUNS HAVE NOT TRENDED MUCH SLOWER WITH THE NRN PART OF

THE TROF OVER THE PAST DAY...BUT HAVE TENDED TO HOLD BACK MORE

ENERGY IN THE SRN PART. VERIFICATION AND TRENDS WITH SHORT RANGE

FEATURES OVER THE WEST GENERALLY FAVOR THE SLOWER WRN HALF OF THE

OVERALL SOLUTION ENVELOPE. THUS A NON-GFS CONSENSUS IS THE MOST

LIKELY SCENARIO. THE SAME IS THE CASE FOR FLOW AMPLIFYING FROM

CANADA...WITH THE GFS ON THE FAST SIDE OF THE SPREAD FOR THE

LEADING COLD FRONT THAT SHOULD REACH THE US NRN TIER BY DAY 5 WED.

SPREAD IN NERN PACIFIC DETAILS BY DAYS 6-7 LOWERS CONFIDENCE IN

ANY ONE PARTICULAR SOLUTION...BUT THERE IS A GENERAL THEME TOWARD

BRINGING LESS ENERGY INTO THE ERN PAC MEAN RIDGE THAN FORECAST BY

THE 00/06Z GFS RUNS. THIS PREFERENCE LEADS TO LOWER HEIGHTS

DOWNSTREAM OVER THE WRN US. TELECONNECTIONS RELATIVE TO THE CORE

OF POSITIVE HEIGHT ANOMALIES OVER THE ERN PAC AS OF D+8...EVEN

WHERE FORECAST BY THE 00Z GFS...FAVOR LOWER WRN OR W-CENTRAL CONUS

HEIGHTS THAN FORECAST BY THE GFS AND TO A LESSER EXTENT THE GFS

ENSEMBLE MEAN. THE ECMWF HAS THOUGH MODERATED ITS WWD EXTENT OF

ITS LATE PERIOD WRN TROF COMPARED TO ITS PREVIOUS TWO RUNS WHILE

THE CMC IS A LITTLE FARTHER EWD AND THE ECMWF ENSEMBLE MEAN NOW

SOMEWHAT BROADER AND FLATTER WITH ITS TROF. AS SUCH UNCERTAINTY

IS NO BETTER THAN AVERAGE FOR THIS TIME RANGE GIVEN THE UNCLEAR

NATURE OF EMBEDDED UPSTREAM KICKER IMPULSE WAVELENGTH SPACING.

ACCORDINGLY TO REFLECT CONSENSUS PREFERENCES THAT LEAN AWAY FROM

THE 00Z GFS FOR SIGNIFICANT FEATURES DURING THE PERIOD...HPC DAYS

3-7 MON-FRI GUIDANCE WAS PRIMARILY DERIVED FROM A BLEND OF THE 00Z

ECMWF AND ECMWF ENSEMBLE MEAN BUT HEDGED IN 20% GFS ENSEMBLE MEAN

AMID LINGERING UNCERTAINTY.

[Srain]

Morning e-mail from Jeff:

Winter Storm responsible for powerful winds over the SW US moving toward TX.

Strong cold front currently extends from near Dallas to NW of Austin to near Del Rio with temperatures in the 20-40’s behind this front and in the 60-70’s ahead of the front. This front is nearly stationary and will remain near this line for much of the next 24-36 hours. Out west a large trough continues to dig over the SW US and this trough will force downstream pressure falls late today over SW/W TX with surface low formation. Onshore flow of warm and muggy air will remain in place over much of TX east of I-35 for the next 24 hours helping to pump moisture into the region.

Upper trough over the SW US will eject out a shearing piece of energy Saturday late into Sunday pushing the strong cold front over central TX toward the coast. Still some timing differences on how fast the front moves toward the coast with some models showing a Sunday PM coastal passage and others not until Monday afternoon…will side with the faster passage around Sunday afternoon/evening. Prior to the front reaching the area will continue to see a south to north band of showers from roughly Matagorda Bay to west of College Station and this area should see the best rain chances until Sunday when more widespread rains are likely. Could see a few thunderstorms on Sunday along the front/pre-frontal trough, but chances look marginal as instability looks weak.

As the current upper trough shears out on Saturday/Sunday another upper trough digs into the SW US late Sunday creating a classic overrunning pattern over the state. Shallow cold dome will be in place over much of the area by early Monday with warm moist 850mb flow pumping Gulf moisture northward over this cold air mass producing widespread clouds, drizzle, rainfall. Thick clouds and rainfall will keep highs on Monday in the low 50’s. Widespread rains are likely with amounts Saturday of less than .25 of an inch and then .5-1.5 inches on Sunday. Widespread rainfall of 1-2 inches additional will be possible Mon-Tues, producing great drought relief over the region. Slow soaking rainfall may actually create some amounts of run-off into falling lakes. Best post frontal rains look aimed at areas north of I-10 ahead/along the 850mb front, but everyone should see some rainfall over the next 4 days. SW counties around Matagorda Bay remain the driest as recent rains have largely missed this region.

Secondary upper trough will eject across TX Tuesday with rains ending from west to east Tuesday afternoon/evening. Profiles remain warm enough to keep everything liquid over SE TX Tuesday and when profiles start to cool enough to favor frozen precipitation, most of the moisture will be east of the region. Will keep an eye on the NW counties for late Tuesday just in case the models are off on their timing of rainfall ending allowing more cold air to flood the low to mid levels and possibly mixing some of the rain with sleet…this is a remote chance at this point. Most areas will not get much above the mid 40’s on Tuesday for high temperatures.

Upper trough will be east of the area by early Wednesday with clearing skies resulting in potential for freezing conditions possible Wednesday morning, but this is highly dependent on how quickly skies scatter out Tuesday night.

[bubba hotep]

Continued subtle changes are making the Sunday afternoon into Monday night time frame somewhat interesting up here just out to the NE of DFW. I won't have time to really sit down and go through all the guidance until Saturday night when I return from my trip so that will keep me from making some idiotic statements over the next couple of days!

Also, how do we hide avatar pics in this new setup? I glance at this at work and some of the avatars are just not what I want people seeing on my screen.

[Srain]

Also, how do we hide avatar pics in this new setup? I glance at this at work and some of the avatars are just not what I want people seeing on my screen.

Go to the Top/Left. Your profile setting is there. Also on the bottom left is the skin setting. If you are mobile, you may need to switch that.

[Msalgado]

We are still trying to figure out good bounds. I would post any mountain related disco in the "Mountain W" thread.

I don't post all that often, but when I do post about local wx, I tend to post in both this thread and the Mountain thread. I feel as though both apply. I live in Santa Fe at the base of the Rockies, but I go to school in Albuquerque which is more along the lines of the thread that was just mentioned.

I do think a desert sw thread would be a dud, though. I'm pretty sure I'm the only NM poster here and I really post very very sporadically. I don't think there are too many NV posters but I know we have at least a few in AZ and UT.

[#NoPoles]

I don't post all that often, but when I do post about local wx, I tend to post in both this thread and the Mountain thread. I feel as though both apply. I live in Santa Fe at the base of the Rockies, but I go to school in Albuquerque which is more along the lines of the thread that was just mentioned.

I do think a desert sw thread would be a dud, though. I'm pretty sure I'm the only NM poster here and I really post very very sporadically. I don't think there are too many NV posters but I know we have at least a few in AZ and UT.

well, it def would not be a high traffic thread...but i wanted to post about the snow, and santa ana winds in the desert sw...however, there is no place to post specifically about the desert sw...and since this seems to be an active pattern, i did not want to clog any of the other threads...

[msp]

any of the above options sound good to me, but i do advise setting rather definite boundaries for each regional thread and making sure that all locations in the central/west have a disco thread. if you build it, they will post. it may be quiet, but if an area has no thread, there won't be posts at all.

[Srain]

One of the main issues with the guidance has been when and where will the 2nd upper air disturbance (500mb) travel as it heads E. The 12Z Euro suggests a track very near the Red River Valley/N TX. That will be one of the interesting developments to watch over the weekend as there have been a lot of questions in the forecast as to just how/where that disturbance eventually ejects.

[#NoPoles]

look at that sweet pair of double.............troughs

[David Reimer]

Considerable differences between the 12Z NAM and the 12Z GFS in regards to the placement of the 850 MB low by Monday Morning. If the 12Z NAM is correct, a strong southerly low level jet will drag significant amounts of warm air northward and keep the D/FW metroplex above the 35 degrees all day Monday. If the GFS is correct, a strong northwesterly flow will cause cold air advection which will drop us down below freezing by noon, resulting in several inches of sleet and snow. In my opinion, this has the potential to be a high impact event. Where that zone ends up is still quite uncertain, but man do I love winter forecasting!

[Srain]

Considerable differences between the 12Z NAM and the 12Z GFS in regards to the placement of the 850 MB low by Monday Morning. If the 12Z NAM is correct, a strong southerly low level jet will drag significant amounts of warm air northward and keep the D/FW metroplex above the 35 degrees all day Monday. If the GFS is correct, a strong northwesterly flow will cause cold air advection which will drop us down below freezing by noon, resulting in several inches of sleet and snow. In my opinion, this has the potential to be a high impact event. Where that zone ends up is still quite uncertain, but man do I love winter forecasting!

It can be like throwing darts... Still a lot of questions this morning. The Euro drys things out too quickly and the GFS suggests rain/snow/sleet mix W of Dallas with even light snow accumulations. My best guess is that areas from San Angelo to Decatur has the better chance of seeing some light snow, but all that is still subject to change...

Edit to add the Canadian has been rather insistent in developing a Coastal Low near Corpus Christ and that trend continues with the 00Z run. Right now it appears to be a bit of an outlier, but I've seen that model be more correct in the winter than the NAM/GFS with this type of setup of a stalled frontal boundary near the coast. Just perhaps some sleet mixed with rain could fall as far S as the northern suburbs of the Houston area if it is correct...

[Srain]

It appears the GFS trended a bit to what the Canadian has been suggest re: Coastal Low development potential along the Middle TX Coast on Monday. The Canadian now suggest a bit stronger 5H feature and the GFS made a bit of a step in that direction as well. Both the GFS and Canadian wrap up a surface low to our E. Over running precip may linger a bit long into Tuesday and just perhaps open the door a bit more for some freezing rain/sleet/snow combination for Central and N TX. We will see...

[DoctorMu]

That coastal low could end up being Nor'easter material on the East Coast.

[Srain]

The front is nearing Austin at this hour. It appears some earlier forecasts of a slower frontal passage may be in trouble. HGX has adjusted FROPA into northern areas much quicker than guidance had suggested. I suspect other adjustments are ahead as the 5H disturbance is much stronger than guidance had indicated. It could make for an interesting 24-36 hours across TX.

[Ed Lizard]

The front is nearing Austin at this hour. It appears some earlier forecasts of a slower frontal passage may be in trouble. HGX has adjusted FROPA into northern areas much quicker than guidance had suggested. I suspect other adjustments are ahead as the 5H disturbance is much stronger than guidance had indicated. It could make for an interesting 24-36 hours across TX.

Latest HGX update- the front is progressing even faster than they thought when they did the morning disco.

6Z GFS and 12Z NAM like the best rain North of SETX, but both have some rain, with 6Z GFS extra happy, between 3/4 and an inch of rain locally. HOU does look like ti is avoiding the showers to all sides, the models depicting a local min in precip may be on to something, but I'm glass half full.

Light upslope precip (aided by proximity to the upper low) on the models in the Northwestern Texas Panhandle and New Mexico shown on the models should be wintry, Amarillo is currently 20ºF. B-r-r-r-r-r! AMA disco doesn't think the snow will be heavy enough to justify even a WWA.