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

[Srain]

The 12Z WRF/NMM continues to suggests a much further W short wave and a bit more potent feature for Thursday. All the guidance had us bone dry and warm all this week. What is becoming clear is a weak frontal boundary will stall along the coast setting the stage for some over running showers/light rain and increased fog chances as we head into the weekend. What happens with that next potent upper low remains to be seen.

What is getting my attention is the cold weather that is lurking in the mid month time frame. The Euro has joined the GFS in suggesting a –AO, -EPO and –PNA regime that bodes well for Arctic intrusions into the Western 2/3 of the CONUS. A +NOA would suggest a SE Ridge would remain, sort of locking the cold in the Western Areas and keep our neighbors along the East Coast warm. There is also some indications that some MJO help is in the works as it travels from octant 5 toward 6-7-8, although weak. Add into the mix another SSW (Sudden Stratospheric Warming) event now showing up via the Euro. We now see all the guidance sniffing significant cold air building across NW Canada and a relaxation of the ever present Alaska Vortex. Heights are now forecast to build across the Aleutians into the Arctic region suggesting the coldest air of the season will build on our side of the hemisphere. The mid to late January time frame is becoming increasingly interesting for the cold weather lover and just perhaps other miracle chances will come when conditions would be much better. Stay Tuned!

[Ed Lizard]

Cold source region (Canada) is very warm, that makes surface temps unfavorable for wintry precip...unless upper low is potent, moist, slow and surface is a bit dry (evaporational cooling/wet bulbs), I would be against any snow miracles, on top of the rarity of such events in SE TX. But I will cheer for you, the underdog gets my support most of the time.

If snow miracles happen every year, they wouldn't be miracles. And the occasional heartbreak of a busted snow miracle, like February's predicted 3 inches which turned out to be freezing drizzle, only makes the rare snow miracle more special.

Look at the 2004 Brownsville, Texas snow miracle. First measurable snow in 110 years. Would that have been a miracle if it snowed every other year in Brownsville.

Amazing how with limited exceptions the snow obeyed the Rio Bravo del Norte and didn't cross...

[wxmx]

If snow miracles happen every year, they wouldn't be miracles. And the occasional heartbreak of a busted snow miracle, like February's predicted 3 inches which turned out to be freezing drizzle, only makes the rare snow miracle more special.

Look at the 2004 Brownsville, Texas snow miracle. First measurable snow in 110 years. Would that have been a miracle if it snowed every other year in Brownsville.

Amazing how with limited exceptions the snow obeyed the Rio Bravo del Norte and didn't cross...

Yep, that makes the IMBY snow a little more special, since it would be part of an exceptional setup. From what I have researched, MBY has lower probabilities of a snow miracle overall, though my chances for over 15" are maybe just slightly higher, because of the probability of a stationary cut off low over the MX plateau...though that's just once a century occurrence.

[Ed Lizard]

Yep, that makes the IMBY snow a little more special, since it would be part of an exceptional setup. From what I have researched, MBY has lower probabilities of a snow miracle overall, though my chances for over 15" are maybe just slightly higher, because of the probability of a stationary cut off low over the MX plateau...though that's just once a century occurrence.

You ever get the close but no cigar snows where the peaks are white capped after a storm but its rain in Monterrey? Ever seen snow on La Silla? It has an extra ~1000 meters elevation, no?

I've seen on TV snow caps on the San Gabriel mountains East of Los Angeles.

[wxmx]

You ever get the close but no cigar snows where the peaks are white capped after a storm but its rain in Monterrey? Ever seen snow on La Silla? It has an extra ~1000 meters elevation, no?

I've seen on TV snow caps on the San Gabriel mountains East of Los Angeles.

Not quite white capped, but Feb last year had some white after around 1-3" of snow fell in the Sierra...I think the same happened in Jan 96, I have seen photos with some white in the mountains. Dec 97 saw moderate snowfall in all the city, but with temps hovering around 1-2C, little sticked, but 3-6 and maybe more accumulated in the mountains...the problem is that the cloud ceiling was very low, and the next day when I woke up, everything was gone as temps soared past 10C

[Srain]

Morning e-mail from Jeff:

Quite start to 2012 will continue as zonal and dry upper level pattern prevails across Texas.

Surface high pressure is moving off to the east allowing very weak onshore flow to develop. Smoke from wildfires burning in southern Jefferson County (10,000 acres) should stay east of the region today with more of a southerly flow transporting the smoke more northward than westward. Low level moisture will slowly return to the region ahead of a weak front which will move off the coast early Thursday. This front will briefly turn winds northerly and knock a few degrees off the high temperatures for Thursday. As this front stalls over the coastal waters a weak upper level low develops over N MX and moves across TX Friday, but with severely limited moisture, rain chances will be less than 30% and confined mainly to the coast where coastal troughing offshore may provide better lift and where the best moisture is found.

Gradual warming into the weekend ahead of another weak front on Sunday which will swing winds back to the north and cool temperatures back toward normal. Highs Saturday will warm into the lower 70’s under increasing southerly winds and clouds. Moisture once again looks limited with the frontal passage on Sunday, so the drier pattern will continue into the weekend.

Models begin to diverge on timing and intensity of the next storm system indicated for early next week. GFS is once again the most progressive while the ECMWF is slower and stronger. ECMWF would give the region a much better shot at rainfall. For now will trend in that direction….toward the ECMWF model, but the forecast confidence for early next week is low. It will be cooler however with clouds and possible rain behind the Sunday cold front going into Monday and Tuesday.

[Big O]

JB tweets that GFS Ensemble maps depict serious cold into US (i.e., "as if God let me draw the maps").

[Ed Lizard]

JB tweets that GFS Ensemble maps depict serious cold into US (i.e., "as if God let me draw the maps").

Not quite centered in our neck of the woods, but a little chilly at any rate.

[bubba hotep]

Ed - Don't look at the 18z GFS post 200 hrs!

[DoctorMu]

some 12 z models....verrrrrrry interesting.

[DoctorMu]

Ed - Don't look at the 18z GFS post 200 hrs!

lol A Friday the 13th to remember?

[Ed Lizard]

Of more immediate interest, although no risk areas outline Day 4-8, some hope for "fun-derstorms" in the SPC long range outlook.

[Srain]

The HPC surface progs are out for next week and they paint an interesting picture. The qpf forecasts are suggesting a potential 3+ inches of rain beginning Sunday into Tuesday. The surface charts do suggest a modified Arctic boundary pushing through Thursday finally clearing us out and setting the stage for a very chilly late week into next weekend. We will see...

[Quixotic1]

FWD NWS saw fit to put the ENSM AOI graph up on its site. 18z GFS showing similar pattern to December although looks to be chillier. Something to look forward to. Still looks very progressive as we alternate from warm to cold.

[Srain]

Guidance is coming together suggesting a very active period beginning on Sunday. There are some hints of severe storms with gusty winds and small hail possible as a potent upper low slowly organizes in Northern Mexico and a stalled frontal boundary meanders near Central/SE Texas and a Coastal Low dvelops along the Lower/Middle Texas Coast. Rain and showers look to increase beginning from W to E on Sunday as the slow moving 5H low organizes and deepens near or just S of the Big Bend Region. While the exact track remains uncertain and this disturbance is now closing in on the Pacific NW, indications do suggest a stormy period is ahead.

This feature will enter the RAOB network Friday into Saturday as it moves onshore and drops SSE into the Great Basin/4 Corners Area. Winter Storm conditions may be expexted in New Mexico Saturday night into Sunday. The early QPF forecasts suggest 2-3 inches of rain, mainly E of the I-35 corridor with isolated 4+ inch amounts possible just N of the Houston Metro area. Training of storms may be possible and Flash Flood criteria may be met.

As the closed cold core upper low treks E, cold air aloft could bring elevated storms with small hail as the upper levels will be very unstable. There are some indictions a trowal like feature will develop N of the U/L, and depending on track and profiles, wintry mischief may be possible. As the storm system passes, a strong push of cold Canadian air looks to be tapped as yet another Winter Storm winds up along the northern stream near the Great Lakes/Upper Mid West. A strong front appears likley Wednesday night into Thursday morning. Light snow may develop across the Southern Plains as this boundary dives S. Stay tuned as we appear to be heading into a very active period!

[Srain]

[JoMo]

You all have had a fair share of fantasy storms for SE Texas this year it seems.

[bubba hotep]

Just need the NW trend to kick in!

[Ed Lizard]

You all have had a fair share of fantasy storms for SE Texas this year it seems.

If you assume the CMC is correct, that is a dusting or an inch worth (about/under a tenth liquid) falling after happy thicknesses pass, it'll be pretty, but it'd probably doesn't stick to the grass much.

And its the Canadian.

Now, if you include our friends at the big Ag school 90 minutes Northwest of Houston as being SETX, however, that would be a joyous occasion, a couple of inches.

Probably not a school canceller, but the last time it snowed up there, I there are almost real time cameras to catch snow at Kyle Field.

1/32nd glass full optimism for Kyle Field snow pix. 1/128th glass full for my lawn turning white, the definition of a snow miracle. (Obviously, snow further down the coast is always a miracle).

I'm more psyched about TTs over 50 with some low-mid level directional shear, and even some weak surface instability Monday myself, per the GFS.

[Srain]

Afternoon e-mail from Jeff:

Warm and humid conditions prevail through the weekend before the next storm system and colder weather arrives next week.

Weak washing out frontal boundary over the coastal counties and an eastward moving upper air disturbance is creating a few showers near the coast early this afternoon. Bigger problem in the next 48 hours will be formation of dense sea fog as near shore dewpoints exceed water temperatures along with light winds. Sea fog will be likely tonight through Sunday night near/along the coast and in the bays and spreading inland each evening. Visibilities of less than ½ of a mile are likely in the sea fog bank.

Next weak front will pass across the region on Sunday and this will begin a change for the region by early next week. While this happens a potent upper level storm will dig into position over the SW US with downstream sub-tropical jet coring across TX by late Sunday. Moisture will remain high over the area and increase by late Sunday while surface boundary stalling near the coast/just offshore begins to lift slowly northward as a warm front. Combination of increasing lift and favorable jet dynamics points to widespread rain developing late Sunday into Monday with some heavy at times especially near the northward lifting warm front. Models are typically too fast lifting such boundaries northward when rainfall is in progress and would like to hold the boundary closer to the coast/US 59 corridor and this may be the region where some hefty rainfall totals may accumulate on Monday.

Next and stronger front will cross the region Monday afternoon, but the upper level storm/trough remains west of the region for a period helping to induce a period of moisture being pulled up and over the frontal slope. Additionally the surface and upper level storms will intensify while crossing TX leading to some potential for wrap around rainfall in the colder air especially north of HWY 105 into Tuesday morning. Lack of cold air across the nation will keep everything liquid with this storm system.

Fairly decent period of moisture advection into the region will support some heavy rainfall potential from Sunday PM –Monday PM across the region. While too early to pin point exactly where the heavy rains will fall, warm frontal boundary position is usually a good indicator for such potential. Widespread 1-2 inches appear likely with isolated amounts of 2.5-3.5 inches especially where cell training develops.

It will be warm and muggy through the weekend and then turning colder Monday, or at least back toward January temperatures of highs in the upper 50’s and lows in the 30’s by Tuesday.

[bubba hotep]

18z NAM looks to crush us up this way. 12z GFS ensemble would also be a hit. Looks like this might end up being a nice soaker.

ETA: looking at stuff on train and 18z NAM would bomb Lubbock and the GFS would get flurries into the DFW area...

[Srain]

Once again, as we saw in December, these closed cold core upper lows are a forecasting challenge at best. This morning we see Winter Storm Watches hoisted for New Mexico with Special Weather Statements for winter weather from El Paso, Midland/Odessa, to Amarillo. San Angelo has joined in the question of whether they will see wintery mischief across their area and even Dallas/Ft Worth is mentioning the possibility of a wintry mix to their W as the upper low treks E. Further S, rains and storms look likely beginning late Sunday into Tuesday morning. The SPC is mentioning even a possible tornado or two for S Texas as a Coastal Low develops. It does appear that heavy rains and storms are likely for Central/SE TX Sunday night into Monday night/early Tuesday morning. There still remain some uncertainty on the exact track of the U/L and precip could linger into Tuesday as the closed cold core upper low passes. The focal point for heavy rains will be along a stalled frontal boundary draped across Central/SE TX and wide spread 1-2 inch amounts, with isolated 4+ inch amounts possible where any training of heavy showers/storms develop.

A stronger push of colder air should follow on Thursday as a complex Winter Storm develops near the Great Lakes/Upper Mid West and a Canadian front dives S into the Plains in the wake of our passing storm early next week. Model volatility returns yet again with what happens with yet another upper low to our W on Wednesday/Thursday and just when that feature will eject E. Sound familiar? Various solutions and day to day, run to run solutions are offered by the various guidance and a very changeable forecast lies ahead regarding late next week. What is developing via guidance is heights increasing near/over Alaska and a break down of the Alaska Vortex that has brought record cold and snows to Cordova/Prince William Sound and cold temps are pushed into Western Canada and Arctic high pressure builds in the 1048-1055+ range and extends to the N Pole.

What often happen when a whole sale pattern change occurs are guidance flip flops and various solutions will change like the hands on a clock. It does appear we are entering a period where cold air intrusions are becoming more likely as we head into mid January. There still remain indications the a favorable MJO in phase 7-8, albeit weak will allow tropical forcing to keep the Pacific pattern active for us before relaxing later this month. A -AO/-EPO regime with a waffling +/-PNA is conducive to a cold and active pattern for the Western 1/2 to 2/3 of the North America while the East Coast remains warm with a +NAO or lack of Greenland blocking. The SE ridge tends to hold the cold air intrusions W as storm systems trek NE into the Ohio Valley or W of the Appalachians. All that said, stay tuned! We are entering a very changeable period and cold air intrusions well S into Mexico cannot be ruled out as a cross Polar flow may develop and depending on exactly where the Alaska Vortex is displaced, or takes up shop in Canada. My hunch is we are entering a very interesting period, weather wise so hang on. It could become a very bumpy ride...

[Srain]

A very wet and wintry solution is showing up via the 12Z NAM. Accumulating snow in New Mexico, W and N Central Texas as well as the Southern Panhandle is suggested with heavy rains/storms further S in the warm sector near the stall frontal boundary. The Upper Low deepens over N Central Texas and a Coastal Low develops near Corpus setting the stage for a very active 3-4 days...

[bubba hotep]

A very wet and wintry solution is showing up via the 12Z NAM. Accumulating snow in New Mexico, W and N Central Texas as well as the Southern Panhandle is suggested with heavy rains/storms further S in the warm sector near the stall frontal boundary. The Upper L ow deepens over N Central Texas and a Coastal Low develops near Corpus setting the stage for a very active 3-4 days...

It is looking more and more like we will get a nice soaking up here in DFW, esp out here NE of town.

[Srain]

The 12Z GFS continues the trend of the NAM that was suggesting a wet and wintry several days across New Mexico and parts of Texas. The GFS also deepens the upper low over N Central Texas and drops plentiful beneficial rains in the warm sector along the stalled boundary and just N of the Coastal Low with higher totals suggested for drought plagued areas SW of Houston...

[Srain]

ABQ issues Winter Storm Warning and expands Winter Storm Watches to TX border. MAF issues Winter Storm Watch for areas along and N of I-20. SJT mentions wintry mix for their CWA and FWD mentions wintry mix for their NW CWA. HGX increases chatter concerning severe weather threat and heavy rainfall potential.

[Srain]

LUB issues Winter Storm Watch for areas from LUB and points S. OUN mentions light snow possible Monday into Monday night.

[Srain]

AMA now calling for 1-2 inches of snow. Will consider Winter Weather Advisory tomorrow morning if trends warrant for Monday

[wxmx]

The winter storm behind the one Mon-Tue is looking a little better (Thu-Sat), with colder air to work with. The CMC is holding ground and now the GFS is closer to the canadian solution. The Euro cuts off the low well offshore, hence tightening the jet well north of our area with less amplification. The 0z Euro will be interesting.

[Srain]

Let’s get the immediate weather concerns out of the way first before we get into what may happen later next week. Fog has formed mainly S of I-10 and foggy conditions may linger until mid morning. Guidance is in good agreement concerning wintry weather in W and N Central Texas and with showers/storms and heavy rainfall chances in the warm sector. Showers and some heavier storms begin to fire in Central Texas Sunday afternoon/evening and spread E overnight. At the same time a Coastal low develops and heavy rainfall chances increase early Monday throughout the day and a risk of training showers/storms may be possible along and N of the boundary/surface low on Monday.

Back in the cold sector, light wintry precip appears very likely from New Mexico, W Texas and perhaps the N and Western Hill Country on into the Southern Panhandle has guidance suggests a bit of a southern trek of the deepening upper low.

The Euro/Canadian/UKMet solutions all suggest the storm track will be across Central Texas. Wrap around precip is possible on Tuesday if the Euro solution plays out as it passes the U/L over SE TX and on ENE.

As this storm system passes, a northern stream storm develops and a strong cold front begins diving S into the Plains with Canadian air. All the guidance drops another upper low inland along the W Coast. The Euro continues to advertise a slow/stall solution while all other guidance suggest this feature will trek ESE from the Desert SW as the strong front passes Texas on Thursday. This is when the guidance begins to diverge. As we saw, the Canadian has been insistent on a wintry mischief solution for several cycles. The GFS has hinted at this and the GFS Ensembles would suggest that there is a chance of that happening. The UKMet has the upper air feature and the front and cold air in place, so it tends to agree. The Operational Euro suggests the cold stay to our N and the U/L lingers W and is delayed by a couple of days. Examining the Euro ensembles, there is a change with the 00Z output suggesting enough cold air in place and the spread would also suggest the U/L is further E near or S of the Big Bend Region.

Once we get beyond the storm at hand, all eyes will turn toward the possible weather events prior to the Olympic Trails Marathon on Saturday. Stay tuned as we appear to be headed toward a very interesting period and much colder air may be on the horizon in the longer range beyond next weekend.