Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 6

[Portastorm]

Starting Part 6 of the discussion ...

[Nairobi]

Latest parallel GFS run is much faster and much weaker with the 12/21 system. The next system is intense (climatologically relative to its position) and cuts off to the east of central Baja at 240 hours.

No arctic air to be found per this run at 240 hours.

[Nairobi]

ECMWF operational also showing nothing arctic at 240 hours.

Ditto JMA at 192 hours.

[Nairobi]

228 hour (12/22) 6am temperature anomaly, per parallel GPS. Nothing severe.

[Srain]

Winter Storm Warnings have been hoisted for the Sangre de Cristo Mountains near Taos with the storm system currently spreading moisture over Arizona. This storm is related to the split flow Pacific jet streak that has been imp[acting the West Coast and this 160kt + jet streak should continue to bring Southern tracking storms across our Region into next weekend. There are at least 3 additional shortwaves depicted to impact the southern portion of our Region beyond tomorrow into Monday. The guidance is struggling with the potential strength of the disturbances, but it appears the next 'stronger' shortwave will be impacting the Region late next week.

[bubba hotep]

I'm not so concerned with the temp anomalies at this range but obviously we need the negatives in our favor. The main issue with the 00z Euro run last night was the evolution of the 500 mb across the northern plains and NE. Pretty big difference b/w that run and yesterdays 12z run leading up to the pre-Christmas system.

ETA: I really like what the ensembles are showing in the 11 - 15 day range, even if the pre-Christmas system doesn't workout

[Srain]

I'm not so concerned with the temp anomalies at this range but obviously we need the negatives in our favor.  The main issue with the 00z Euro run last night was the evolution of the 500 mb across the northern plains and NE.  Pretty big difference b/w that run and yesterdays 12z run leading up to the pre-Christmas system. 

I totally agree. Roll the 00Z Euro mean forward and you can 'see' heights building along the West Coast and ridging into Eastern Alaska/Western Canada. As those heights build N, a deep trough develops along and E of the Continental Divide suggesting a stormy period with 'colder' air arriving. We are going to see the northern and southern stream disturbance begin to drop some snow across the Plains that has been lacking since November. The other Global ensembles are in rather good agreement that the pattern shifts around Christmas and continues into the New Year. The anomalies suggesting all the warmth are not unusual at all in our part of the world. We see those warmer temperatures with wild swings all the time. The good news is the dent we are making in the drought and that bodes well for next Spring. Keep those Southern storms coming and eventually they will deliver the goods.

 

 

 

[Quixotic1]

'Twas ten days before Christmas, and all about my yard

My Bermuda grass is regrowing. I'm not much of a bard.

Seriously, as we approach winter solstice, is that even possible? Even in 11-12 my yard was deader than fried chicken.

[bubba hotep]

'Twas ten days before Christmas, and all about my yard

My Bermuda grass is regrowing. I'm not much of a bard.

Seriously, as we approach winter solstice, is that even possible? Even in 11-12 my yard was deader than fried chicken.

 

It is still 12 days before here at Chateau Hotep and all the grass is dead 

 

The 12z Euro ESP D15 sure has a chilly look to it and the operational is trolling the Mid-Atlantic, doesn't get much better than that for a Saturday.

 

ETA: 18z GFS has 1040+ highs stacked up as far as the eye can see 

[Nairobi]

ECMWF operational still showing no arctic intrusions for Texas through 12Z 12/23. The 850 mb anomalies forecast map at 240 hours:

[Quixotic1]

It is still 12 days before here at Chateau Hotep and all the grass is dead 

 

The 12z Euro ESP D15 sure has a chilly look to it and the operational is trolling the Mid-Atlantic, doesn't get much better than that for a Saturday.

 

ETA: 18z GFS has 1040+ highs stacked up as far as the eye can see 

Ha. Good catch on the days.

Seriously, the bottom 1/2" of my grass is green.

I remember in January 85, we had a 4" snowstorm on New Year's after a dismal warm and wet December. It went right back to being warm again. On the 19th it went from 70 all the way down to 6 IMBY with 50 mph winds. I remember the long green grass snapping off as I walked along my paper route.

[Srain]

Thankfully my San Augustine is dormant.  Nice little base building event for Taos, Angel Fire and Red River. Good time for a trip to see Mt Wheeler.

[Nairobi]

Surface low pressure anomalies widespread across North America on Christmas Eve, per ECMWF operational.

Christmas Eve morning up to 5 degrees F below normal across Texas per parallel GFS

But dry per the same model.

[Nairobi]

The only significantly below normal 6am surface temps progged by the GFS ensemble mean for Texas is at 378 hours.

[Srain]

Late Sunday evening briefing from Meteorologist Jeff Likened (Harris County Flood Control District):

Frequent weather changes coming to TX over the next several days.

 

Initial storm system moving into the central plains this evening with a trailing line of thunderstorms into N TX and scattered showers in the warm air advection regime over SE TX. Main dynamics are well north of the region and the surface cold front is well west of the area over W TX. Dry air is noted above the surface helping to keep rain showers scattered and light. Will likely see a slight increase in shower activity as the cool front crosses the area tomorrow afternoon. Post frontal air mass is Pacific in nature so only a slight cool down…or back to near average from the  above average warmth of late.

 

Tuesday will by partly cloudy and cool with lows in the 40’s and highs in the 60’s (near normal).  

 

Southern stream jet will remain very active with next upstream storm system rapidly approaching from the west by mid to late week. Surface front over the NW Gulf will bring to return northward as a warm front on Wednesday. Expect warm air to overrun the cool surface dome by late Tuesday with clouds increasing from SW to NE late Tuesday and light rain and fog developing north of the warm front on Wednesday. Models are usually too fast in their northward transport of the warm air mass in such situations and think this will be no different with the front slowly moving inland late Wednesday.

 

Region is warm sectored Thursday and Friday as strong storm system approaches from the WSW out of NE MX on Friday. Expect increasing chances for showers and thunderstorms Thursday with the best chances arriving on Friday. Could see some heavy rainfall Thursday and Friday with good moisture advection. Instability looks limited, so not expecting any severe weather. Temperatures will run above normal again Thursday and Friday with lows in the 60’s and highs in the 70’s. Post frontal air mass behind this storm will be of more Canadian air with temperatures falling into the 30’s and 40’s for lows and 50’s for highs by next weekend. GFS suggest low level moisture may be trapped in the frontal inversion next weekend and this would result in a cold air advection low level stratus deck and keep highs even colder than currently suggested.

 

Christmas Week:

Third storm system appears to arrive 22-24 Dec with another shot for showers and thunderstorms. This storm system however appears to help buckle the upper air pattern with ridging building deep into Alaska and a large downstream trough carving out across much of the US. Bitter cold air mass currently in place over Siberia (-40 to -50F) may shift across the north pole and into NW Canada as the ridge builds into Alaska. This would place extremely cold Siberian air in place to be unleashed southward into the US following the early Christmas week storm system. Forecast models have been hinting at enough upper air pattern amplification during the period between Christmas and New Year’s to suggest at least some arctic air could be in store for the area. Additionally, the southern stream will remain active with storm systems roughly every 2-4 days across TX. While this pattern change is still over 7 days away, operational and ensemble support has been increasing over the last few days and much colder and stormy pattern appears increasingly likely by Christmas week and into early 2015. Main questions over the next several days will be if the coldest air comes straight southward or glances TX and heads more for the east coast and if enough cold air will be in place with any of the storm system to produce any winter precipitation.

[Nairobi]

Highly anomalous (4 standard deviations) southern stream system progged by ECMWF operational for Christmas Eve night.

But it is way ahead of any arctic air intrusion.

Canadian model is similar.

[Srain]

The global ensembles are suggesting an active pattern as multiple short waves embedded within fairly quick moving troughs off the Pacific traverse our Region into Christmas Eve. The next strong storm system arrives Wednesday into Friday bringing heavy mountain snow across New Mexico on Thursday and depending on the eventual track, heavy rainfall across portions of Texas into Louisiana. The 00Z OP Euro is the southern most tracking solution with the 5H closed low tracking across N Mexico, Del Rio and on E to Lufkin while the GFS suggests the upper low crossing NM, Childress and into NE Oklahoma on Friday. If the southern track were to verify, strong to possibly severe storms may be possible across Austin and Houston Friday. A more northern track would favor the Dallas/Shreveport area for stronger storms. This system has a bit more colder air to work with, so the dynamics appear a bit better for heavy rainfall.

An even stronger storm looks likely near Christmas Eve with even colder air in place as the pattern begins to transition. Being more than a week out it is too soon to speculate on the finer details with a wave currently over Eurasia heading E.

The longer range ensembles are in good agreement that a whole sale pattern change is ahead for the period between Christmas and New Years Day. It does appear we are transitioning to a +PDO/+PNA/-EPO/-AO and possibly a -NAO blocking pattern as we near the climatological favored coldest time of year for our Region as January 2015 begins.

[Nairobi]

The Christmas Eve system is just east of the northern islands of Japan currently.

[bubba hotep]

The global ensembles are suggesting an active pattern as multiple short waves embedded within fairly quick moving troughs off the Pacific traverse our Region into Christmas Eve. The next strong storm system arrives Wednesday into Friday bringing heavy mountain snow across New Mexico on Thursday and depending on the eventual track, heavy rainfall across portions of Texas into Louisiana. The 00Z OP Euro is the southern most tracking solution with the 5H closed low tracking across N Mexico, Del Rio and on E to Lufkin while the GFS suggests the upper low crossing NM, Childress and into NE Oklahoma on Friday. If the southern track were to verify, strong to possibly severe storms may be possible across Austin and Houston Friday. A more northern track would favor the Dallas/Shreveport area for stronger storms. This system has a bit more colder air to work with, so the dynamics appear a bit better for heavy rainfall.

An even stronger storm looks likely near Christmas Eve with even colder air in place as the pattern begins to transition. Being more than a week out it is too soon to speculate on the finer details with a wave currently over Eurasia heading E.

The longer range ensembles are in good agreement that a whole sale pattern change is ahead for the period between Christmas and New Years Day. It does appear we are transitioning to a +PDO/+PNA/-EPO/-AO and possibly a -NAO blocking pattern as we near the climatological favored coldest time of year for our Region as January 2015 begins.

 

Yes, the ensembles continue to look interesting and it is nice to finally see solid signs of the pattern change showing up in the 8 - 10 day range on the operationals. The latest CPC super ensemble has some interesting dates showing up in the analog list, including Dec '66 when non-accumulating snows fell across N. Texas, Jan '97 and...  Dec '09!  The dates aren't straight up matches but I find it can be useful to center the CPC SE and look +/- a few days from those dates.  Regardless, the pattern will be much improved and we should get a couple of threats to track as we move into the New Year.  

[Nairobi]

Per the 12/15 12Z parallel GFS, an intense low pressure system in far eastern Siberia on 12/23 spins up cold high pressure in Alaska and the Yukon. But this high pressure is not Siberian in origin.

ECMWF operational shows intensifying 1044mb arctic high pressure north of Alaska on 12/25 and apparently on the move south. It's origin is north central Siberia.

[Srain]

With a 180kt to 190kt jet screaming across the Central Pacific I would expect a lot of volatility in the various guidance sequences until about 48 hours out. That said the shorter range guidance suggests a big hit in snow total across portions of the Southern Rockies. Elsewhere decent rainfall will assist the drought. The pattern is transitioning to colder/stormier regime just beyond the Christmas timeframe.

[Nairobi]

Per parallel GFS, the Highland Lakes watershed again misses out on the heaviest rains through Christmas Day.

Per ensemble ECMWF, only eastern Texas and points east have below normal 850mb temps on Christmas Day.

[Srain]

Morning briefing from Jeff:


More seasonal weather has returned to the region following a cold frontal passage late yesterday.

Fast progressive flow aloft will result in rapid weather changes over the next 24-36 hours. Surface high pressure will move eastward today allowing winds to turn from N to NE and ENE by this evening. The next storm system along the west coast currently will move inland into the SW US tomorrow and across TX on Friday. Surface cool front is stalling over the NW Gulf waters this morning and will begin to move northward as a warm front on Wednesday. 850mb flow becomes southerly late tonight and this will advect a cloud deck inland from the SW across the region as mid level moisture overruns the surface cold dome.

Wednesday will be mostly cloudy and cool with developing light rain and showers from SW to NE. Surface warm front will begin to move northward on Wednesday with fog and low clouds developing north of the boundary. Warm air advection pattern above the surface cold dome will be maximized just west of SE TX Wednesday afternoon and this is where the best rain chances will likely be found (Matagorda Bay to near College Station).

On Thursday the incoming storm system drops into northern MX with surface low pressure developing across SW TX. Warm front will attempt to move inland, but I have my doubts on just how far it may make it. North of the boundary fog and light rain with cool temperatures will be the norm while south of the boundary temperatures will warm into the 70’s and partly to mostly cloudy skies and a passing shower. Best thought at the moment is that the boundary may at least make it to the coast, but maybe not as far inland as US 59 on Thursday.

Main weather event penciled in for Friday as both surface and upper level storm cross TX. Warm front may surge inland late Thursday into early Friday morning resulting in a narrow band of higher low level instability near the coast early Friday. Strong and widespread lift will approach the region from the SW Friday morning into the early afternoon hours. Expect numerous showers and thunderstorms across the region Friday morning into the afternoon. Current thinking is that instability is too low to mention any severe threat, but will need to keep a close eye at the coastal locations which may be warm sectored Friday morning. PWS increase to near 1.5 inches which is fairly high for mid December and would support a heavy rainfall threat, but cell motions look fairly fast and the overall system speed is progressive.

This storm system should exit to the east late Friday with possibly a clear and cool Saturday in place. Some indications that moisture may be trapped in the frontal passage inversion on Saturday keeping skies cloudy for the first part of the day. NW winds will bring in a much colder air mass by Saturday with lows in the 30’s and 40’s and highs in the 50’s. Next storm system rapidly approaches by Sunday and Monday with clouds increasing again by late Sunday and a slight chance of rain by Monday.

[bubba hotep]

Per parallel GFS, the Highland Lakes watershed again misses out on the heaviest rains through Christmas Day.

Per ensemble ECMWF, only eastern Texas and points east have below normal 850mb temps on Christmas Day.

 

Unfortunately, rainfall totals so far this Fall/Winter have been pretty much what you would expect with a weak Nino given the current SST distribution. We should fair better in January but February looks dry, if you roll the analogs forward.  

 

The 00z Euro ESP had a pretty good look in the 11 - 15 day range.  A number of the members and the Control get snow into Texas with the Control run bringing some ridiculous cold down for New Years. 

[Nairobi]

No snow for any part of Texas through noon on Dec. 26 per parallel GFS.

CFS not showing a major cold outbreak for Texas on Jan. 2.

[Srain]

An active period is ahead for Texas into Louisiana beginning Thursday into Friday. A rather strong 5H low/trough currently located near the Washington/Oregon Coast will drop SE as a retreating warm front slowly moves inland off the Gulf. A surface wave of low pressure is expected to develop Thursday afternoon and near Galveston Bay on Friday and approach the Lafayette area Friday night. Heavy rainfall is possible along andN of the frontal boundary. PW's increase to near 2 standard ddeviations above normal. A very impressive 120kt jet streak places SE Texas/SW and S Central Louisiana in a RRQ. Warm sector isolated storms are possible overnight Thursday into Friday along portions of Coastal Texas into Louisiana and Mississippi.

[Srain]

Morning briefing from Jeff:

 

Dynamically strong storm system will move across TX on Friday with heavy rainfall and some severe weather possible.

 

Mid level deck has overspread the region from the southwest this morning ushering in the start of changes in the weather. Surface cold front over the NW Gulf will begin to move northward today while moisture and lift start to increase above the surface cold dome resulting in a weak overrunning pattern mainly across central TX into our western counties today. Light rain, drizzle, and fog will become more widespread tonight as the warm front lifts toward the coast and lift continues to increase as SW flow aloft helps to bring impulses across the area. Still going with a slower warm frontal passage on Thursday as these types of patterns usually like to anchor the front near the coast longer than the models suggest keeping the inland areas in the “soup” for a longer period of time. Air mass will slowly modify with time as temperature slowly warm today-Thursday as the warm front approaches with period of drizzle and light rain Thursday.

 

Thursday night- Friday night:

Powerful storm system currently over the Pacific west of N CA will move into the SW US and then across TX late Friday. Strong lift will force surface low pressure development over S TX early Friday which will help push the warm front inland over SE TX Friday morning. Strong lift comes to bear across the region with both good upper level divergence (spreading apart of the high level winds) and low level convergence along the stalling warm front and then approaching cold front. 120kt jet stream carves into the region Friday morning.  Surface low looks to track near/over SE TX Friday morning into the early afternoon hours and this will be a very active weather period for the region.

 

Heavy Rainfall:

Models prog PWS values to increase to 1.6 inches by Friday morning which is +2 SD above normal for mid December. These high moisture levels combined with impressive lift and a strong warm front surface boundary all point to a heavy rainfall threat along and just north of the warm front position Friday morning. While storm motions will be rapid to the NE and E the potential for cell training for a period of time Friday morning into the early afternoon appears elevated. Global models are suggesting widespread 1-2 inches of rainfall is likely with isolated totals of up to 3 inches possible. Will need to watch the warm front position closely Thursday night into Friday for the best axis setup for heavy rainfall.

 

Severe Threat:

Not overly concerned with the severe threat at the moment. Warm front should make it to at least US 59 with a moist and unstable warm sector extending southward into the Gulf of Mexico. Not sure the warm sector air mass will be that “juicy” given the cool shelf waters and time of day (morning) which usually helps to mitigate the severe threat. Wind shear however will be impressive as the surface low approaches from the SW and with backed low level winds near the warm frontal boundary low level shear will be maximized. Think the overall instability will limit the severe threat as we have seen previously this fall with system. With that said, it does not take as much instability this time of year with strong dynamics to produce severe weather. Will redefine this threat tomorrow.  

 

[wxmx]

Guidance and teleconnections have hinted at a pattern change to colder by the end of the month. Both the op GFS and para GFS have flip flopped on this change several times. The ensembles have been a little more steady, but still the GFS ens, like the op, are more progressive, with a transient -EPO and west coast ridge moving east with the flow into the center of the CONUS, bringing milder conditions to the south. The Euro and it's ensembles, OTOH, have signaled a much more blocky high latitude pattern, with a strong -EPO ridge and a -NAO, with a big, broad trough near the center of the CONUS. The para GFS has been on both sides of the fence, but the latest runs back up the Euro.

 

The difference in pattern is especially notorious for our region. If the Euro comes to fruition, a relative long spell of very cold weather past boxing day would lock for several days. In the beginning of that cold spell, it appears that the STJ is less active than what has been so far, but might get more active past the first week of January. So if the cold lingers for more than two weeks, wide spread wintry weather might be possible.

 

Given that the spread on the GFS is rather above normal, while the Euro ensembles are more similar between them, plus the usual superiority of the Euro, I'm leaning toward the colder pattern right now.

[aggiegeog]

Wow, the 0Z ECMWF shows a very impressive Arctic blast entering Texas at hour 240. At that hour it shows 850 temps of -12C entering Texas and 500MB heights of 564 in Alaska.

[Nairobi]

0Z Canadian ensembles has no freezing temps for roughly the southeast 40 percent of Texas through 384 hours.

ECMWF has roughly 2.3 inches of rain for Austin on Friday and then dry and mild through Dec 26. Looking upstream at progged surface temps at places like Denver and Casper, the cold front possibly arriving Dec 27-28 in Texas is not nearly as cold as the Nov front.