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

[wxmx]

^^ That kind of "if the snow won't travel to Jorge, Jorge will travel to the snow" is what makes American Weather great.

I don't know what I haven't done it before...it was a 2 hour road trip, even going at no more than 60mph...and many times a 25min trip can do it, but it gets too crowded most of the time...unless you know where and when, to get an edge .

Even with a few peaks at 12000ft, snow isn't that common, as most of our precipitation in winter (>80%) comes down in the form of drizzle from stratocumulus, which means that anything above 2000m is either fog or plenty of sunshine with a nice view of "cotton like ground" as far as the eyes can see. Strong s/w's aren't that common.

[bubba hotep]

That is awesome, esp the look on the little ones face! Thanks for sharing.

[Portastorm]

Thanks for sharing your experience with us, Jorge. That is awesome! I bet your kids will never forget it.

[wxmx]

That is awesome, esp the look on the little ones face! Thanks for sharing.

Thanks for sharing your experience with us, Jorge. That is awesome! I bet your kids will never forget it.

Thanks guys! Yeah, this is one that'll stick in their memories, I bet.

[DoctorMu]

Truly amazing pictures from a remarkable event, and lifetime memories

Weather science is like.... Magic!

[wxmx]

Truly amazing pictures from a remarkable event, and lifetime memories

Weather science is like.... Magic!

Thanks for your words....and totally (re: weather science=magic), as I see it like that a lot of times. Kids want to go back ASAP, doesn't matter that we are at 90F right now

[Ed Lizard]

Middle of last week tomorrow looked like a good day per the Euro for "fun-derstorms", so its hard to get excited for the next big thing over a week away.

But, bright side, not much of a cap if the Euro is right.

[Ed Lizard]

40 to 50 knot LLJ, and happy humidities at 850 and 700 mb suggesting capping isn't too bad, its a long way off, but the Euro continues to be glass more than half full...

GFS not as happy, and hence is disregarded for now.

[wxmx]

The Euro has been on and off with a rather strong late season cold wave with a very favorable setup for our region @days 7+. The 0z Euro is on again, with a strong ULL dipping south into AZ, MX, NM and TX , and low heights in old MX (the same tune of the past 3 months)... but this time a stronger Canadian high is coming down...if only we were in January .

[DoctorMu]

The Euro has been on and off with a rather strong late season cold wave with a very favorable setup for our region @days 7+. The 0z Euro is on again, with a strong ULL dipping south into AZ, MX, NM and TX , and low heights in old MX (the same tune of the past 3 months)... but this time a stronger Canadian high is coming down...if only we were in January .

The Euro fantasy is strong.

[DoctorMu]

The front just past Hearne and on its way to BCS. There's a small line of showers on top of the plow, but the Cap is pretty strong...with pcp pretty minimal. Nice gusty northerlies are on their way.

[wxmx]

The Euro fantasy is strong.

In the meantime...first 100F of the year!

[wxmx]

In the meantime...first 100F of the year!

102F with a dew point of 0F with a wind from the WNW...desert like conditions

METAR MMMY 022145Z 30005KT 15SM SCT250 39/M18 A2958 RMK 8/005

An hour later wind shift to the ESE, 94F and a jump in the dew point of 50F

METAR MMMY 022248Z 11011KT 15SM SCT250 34/10 A2960 RMK 8/002

[bubba hotep]

6z GFS looks like a nice soaking for DFW. It looks like we might be breaking the cycle that we have seen the last couple weeks of the models drying up storms for DFW as they move closer to reality. This kind of jives with the MJO possible moving back towards 4/5 and out of the 1-3 area.

ETA: regarding the 8thish of March

[andyhb]

12z GFS looks good for a possible severe event in Central/Eastern Texas next week, is close to phasing the N/S stream as well.

[wxmx]

The Euro fantasy is strong.

It has moderated a tad, but the GFS is colder, very much like the Euro...and the 0z CMC is ... well...crazy as always. I think this will be a big event for TX, either snow, severe and/or plain rain...or even just unseasonably cold.

[icebreaker5221]

It has moderated a tad, but the GFS is colder, very much like the Euro...and the 0z CMC is ... well...crazy as always. I think this will be a big event for TX, either snow, severe and/or plain rain...or even just unseasonably cold.

00Z Euro coming in quite interesting as well, cutting off the low VERY far west. Some sort of a GFS/Euro compromise could mean some very heavy rains for TX/LA and heavy snows for NM.

[David Reimer]

This storm system is still four to five days out and it's already gaining some hype from the local media on the severe potential. I think the heavy rainfall may become the primary story, especially if the GFS is right. We'll see what happens. I had to put something out on the TSC page this afternoon just to calm folks down a bit. Nerves are rattled after Friday.

[thunderman]

This storm system is still four to five days out and it's already gaining some hype from the local media on the severe potential. I think the heavy rainfall may become the primary story, especially if the GFS is right. We'll see what happens. I had to put something out on the TSC page this afternoon just to calm folks down a bit. Nerves are rattled after Friday.

Agreed on the heavy rainfall threat potentially becoming the bigger story with this system. GFS/EC and their ensembles are in acceptable agreement with placement of a weak surface low/inverted trough around Thursday evening with flow off the gulf not being an issue whatsoever.

GFS 850mb streamlines:

GFS Ens QPF:

[Srain]

Model mayhem continues regarding the late week time frame from Thursday to Sunday. The over night guidance still offers little confidence in any one solution. What does appear likely is streamer showers developing late Wednesday underneath a stout cap. The GFS shears out the upper low leaving an elongated trough extending from New Mexico/Arizona much like the Canadian offered yesterday. Now the Canadian has flipped into agreement with the Euro suggesting a cut off upper low meandering over New Mexico in a split flow regime delaying a cold front until late Saturday. Such a solution could bring very heavy rainfall totals across areas of Central/NE/E/SE Texas beginning Thursday into Saturday. With such a slow moving scenario, we could see rainfall totals in the 2-4 inch range with isolated 6+ amounts should training storms develop. This remains a low confidence forecast but warrants attention as there is some potential for a significant weather event later this week. The storm complex will move onshore later today into tonight in the Pacific NW and drop SE into the 4 Corners Region by Tuesday afternoon/evening. This significant late Winter Storm will bring heavy mountain snows to the Southern Rockies. We'll see what the 12Z guidance offers, but those with outdoor plans late in the work week into the weekend will need to follow developments closely.

[wxmx]

One thing that are common in all models is that the air source is now shown as mostly from pacific polar origins, no 1040+mb high anymore, as the W Coast ridge deamplifies quickly after the ULL detaches from the Pacific jet. Agree about the rainfall potential is what we should focus in. The east coast ridge is so strong that the trough goes negative tilted over the Rockies/S Plains and then lifts NNE...not a common configuration.

[Ed Lizard]

Sadly, vigorous fun-derstorms don't seem supported on the modelling, but drought busting rain, that is a good thing.

[wxmx]

0z GFS... ULL mitosis

[Srain]

Morning e-mail from Jeff:

Transition begins today toward a more moist pattern as cloud cover is increasing on southerly winds this morning.

While guidance remains at odds on how to handle the upcoming event for late this week into this weekend, there is slightly better agreement this morning. Surface low pressure developing in the lee of the Rockies today will help instigate increasing southerly winds and a breezy to windy afternoon is in store for the area as south winds gust to 25mph or greater. Low level jet begins to ramp up tonight leading to a rapid increase in low level moisture across the area. Moisture stream off the western Gulf will be capped off between 850 and 700mb, but will deepen enough on Wednesday to likely start to see showers stream inland off the Gulf. Feel the TX Tech 3km WRF model is likely getting to overall pattern correct, but is a little widespread on the amount of rainfall on Wednesday. Think that 30-40% coverage will do with showers increasing toward the afternoon hours.

Large upper level storm system will dig southward down the interior of the Rockies and then stall out over AZ/NM late this week into this weekend. A cold front will drop southward down the plains and into TX Thursday and then greatly slow and possibly stall somewhere over SC to SE TX on Friday. Very favorable inflow of a very moist air mass off the Gulf and Pacific will lead to a saturated air mass by late Thursday. As has been so common for the start of 2012 PW values rise to near +2 SD (1.55 inches) for early March and the threat for repeat cell training along a stalling surface front is really raising the red flags for some sort of heavy rainfall/flash flood event from the period of Friday-early Sunday. Strong surface to 850mb moisture advection off the Gulf will help feed convection. With the upper level low stalled out to our west for 36-48 hours (Thursday-late Saturday) expect disturbances to rotate around the SE side of this feature about every 6-12 hours and this will help to ignite rounds of showers and thunderstorms. With enough breaks between rounds the flooding threat could be minimized however impressive 250mb divergence will position itself near/just WNW of the region and a surface trough is progged by the models to develop from near Matagorda Bay northward to near Dallas. The surface trough will align close to the surface to 850mb inflow off the western Gulf and is located on the favorable portion of the jet aloft. This all points to a sustained heavy rainfall event for multiple periods of time. Still much uncertainty with the timing of the whole event and how quickly the upper low ejects across TX over the weekend (GFS is quick while the ECMWF/CMC hold the thing back until late Saturday). General consensus this morning is to hold the system back to our west and not eject it across until the middle of the weekend following the ECMWF/CMC guidance.

Surface front should stall out Friday across the region with showers/thunderstorms moving SSW to NNE across the area. Front may make it toward the coast by early Saturday with the help of convective outflows along the boundary. Axis of continued heavy rainfall appears to align from roughly the Columbus area to College Station to Dallas. Current thinking is that this is the area where some decent training and bigger rainfall totals could be, but we are still talking over 48 hours out from the event and much can/will change. Will go with widespread rainfall totals from late Wed-early Sunday of 2-3 inches across the entire area with isolated amounts of 4-5 inches. Would not be surprised to see a few 6-8 inch totals given the excessive amounts of moisture that will be in place especially near and just east of where the surface trough/cool front stall out. The overall setup is a fairly common eastern TX heavy rainfall event pattern, but as usual the devil is in the details of where narrow bands of heavy training rainfall will develop and who get clobbered with some really big rainfall amounts. Current thinking is that N/NE TX into NW LA and AR will be the locations under the greatest threat. Or course the water that falls to our north will need to come southward, so there is some concern for some big rises on area rivers with the heavy rainfall axis north/NW of our region.

Severe threat looks overall minimal although a few strong storms will be possible Thursday afternoon near the frontal boundary and then continuing into Thursday night and Friday. Could also see a round of strong storms late Saturday/early Sunday with the ejection of the main upper level.

[Srain]

DAY 3 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0230 AM CST TUE MAR 06 2012

VALID 081200Z - 091200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF NRN/CNTRL TX AND

SRN OK...

...SYNOPSIS...

ECMWF/NAM/CMC/SREF MEAN ARE REASONABLY CONSISTENT WITH MAINTAINING A

DAMPENING CUTOFF UPPER-LEVEL LOW INVOF AZ/NM THROUGH EARLY FRI. AT

THE SURFACE...MODEL SPREAD IS LARGER WITH THE EVOLUTION OF A COLD

FRONT EXPECTED TO STRETCH FROM THE OZARK PLATEAU TO THE TX PANHANDLE

AT 12Z/THU. THE TRAILING PORTION OF THIS FRONT SHOULD ACCELERATE

MORE RAPIDLY SWD ACROSS WRN TX DURING THE AFTERNOON/EVENING AS

RIDGING BUILDS DOWN THE HIGH PLAINS. UNCERTAINTY EXISTS WITH TIME

OVER THE SWD SPEED OF FRONTAL PASSAGE IN CNTRL/ERN TX.

...SRN PLAINS...

ISOLATED TO SCATTERED ELEVATED TSTMS SHOULD BE ONGOING AT 12Z/THU

ACROSS THE TX PANHANDLE INTO PARTS OF SRN KS. CONTINUED LOW-LEVEL

WAA ATOP THE FRONTAL ZONE COMBINED WITH DIURNAL DESTABILIZATION

SHOULD RESULT IN AN EXTENSIVE SWATH OF CONVECTION DEVELOPING ACROSS

OK INTO WRN AR/N-CNTRL TX BY MIDDAY/EARLY AFTERNOON. VEER-BACK WIND

PROFILES AND BROADENING PRECIP AREA SUGGESTS CONVECTIVE MODE SHOULD

LARGELY CONSIST OF CLUSTERS. WITH PRESENCE OF LOWER TO MIDDLE 60S

SURFACE DEW POINTS AND A BELT OF 30-40 SLY LOW-LEVEL FLOW...AN

ISOLATED RISK FOR ALL SEVERE TYPES SHOULD EXIST THROUGH THE

DAY/EVENING.

TSTM COVERAGE SHOULD INCREASE WITH TIME SWWD ALONG THE FRONT IN

PARTS OF CNTRL TX...ESPECIALLY DURING THE LATE AFTERNOON TO EVENING

AS THE BOUNDARY ACCELERATES AND CONVERGENCES INCREASES. ALTHOUGH

SUBSTANTIAL DIRECTIONAL VEERING OF THE WIND PROFILE AND STEEPER

MID-LEVEL LAPSE RATES WOULD SUPPORT RELATIVELY GREATER SUPERCELL

POTENTIAL...INITIATING TSTMS WOULD LIKELY BE QUICKLY UNDERCUT BY THE

FRONT. AS SUCH...THE RISK SHOULD PRIMARILY CONSIST OF ISOLATED

SEVERE HAIL.

[David Reimer]

Confidence continues to increase that we'll be dealing with a fairly potent heavy rain setup across Texas this upcoming weekend. FWD noted that PWAT values are expected to be near record levels. Here's the latest 5 day rainfall graphic from HPC.

[Srain]

The over night guidance still offers little overall confidence with the evolution of a complex weather pattern that includes a cut off upper low near the 4 Corners Region, a shallow cold front and a split flow separation from the mean Polar Jet across Southern Canada/Northern Plains. The models are converging on a solution that does suggest very heavy rainfall with training cells near where the frontal boundary stalls. The SPC currently has a Slight Risk for severe storms for portions of N Central/NE TX into OK and AR for Thursday with large hail and damaging winds being the main threat with a transition to elevated post frontal training cells appear to be the 'bigger' issues as the frontal boundary stalls E of the I-35 Corridor Thursday night into Friday. The Upper Low will slow its eastward progression over New Mexico and the Texas Panhandle on Friday into Saturday before ejecting NE during the day on Sunday. There appears to be multiple waves of short wave energy rotating beneath the U/L making for a very complicated and wet forecast challenge. Another fly in the ointment is a developing surface low pressure system along the stalled frontal boundary in S Central TX Friday night into Saturday. The focal point for very heavy rainfall will be along and to the N of that stalled boundary. The $64,000 questions is exactly where the boundary will stall? Indications are areas from Columbus to just S of Lake Livingston will be the favored areas for heavy training cells, but a slight shift S and E by 20-40 miles may put the Houston Metro in line for a potential flood scenario. That will need to be monitored as events unfold. All in all a general 2-4 inches of rain with isolated 6-8 inch amounts or higher are not out of the question for the favored areas N of the boundary. The boundary should begin to retreat N as the U/L moves NE on Sunday decreasing rain chances as we head into Monday.

[Ed Lizard]

You'd think as the event draws closer the models would start converging, but you'd think wrong.

Flying in a private plane Friday morning to SPS and then on to Norman Friday evening to visit the new wells, one would hope in itty-bitty planes for breaks in the weather, And the red clay soil of SW Wichita County turns into a nasty red gumbo when it rains...

[Srain]

E-mail from Jeff:

Strong storm system to affect the region Thursday-Sunday

An upper level storm system will drop into the SW US today and then slow/stall across this region of the US into the weekend. This will result in downstream wetter conditions over the state of TX starting late Thursday and continuing through much of the weekend. At the surface a cold front will surge southward on Thursday ahead of the upper level storm system reaching the TX coast between 300am-900am Friday. Ahead of this front moisture continues to deepen over the region on gusty southerly winds as a 35-45kt low level jet extends from the western Gulf across much of eastern TX. Moisture levels will saturate the low levels by later today and expect that a few showers will begin to develop and spread northward out of the Gulf of Mexico.

Front arrives Thursday night/Friday morning lifting the moist air mass and producing a band of showers and thunderstorms. SPC Day 2 slight risk area is getting close to our northern counties for Thursday afternoon, but feel the severe threat will be north of our region. Front will slow and stall out along the coast Friday with the large upper storm over the SW US ejecting frequent impulses ENE across the boundary Friday night through Saturday night. Moisture will be forced up and over the surface cool dome allowing of favorable lift. In fact the position of the surface front off the coast and the 850mb front draped near/along I-35 appears to be setting up a favored heavy rainfall event under a front jet aloft and good low level moisture convergence. Moisture levels increase to 2 standard deviations above normal for early March and this raises a red flag with respect to flooding.

Current thinking is that widespread rains will develop Friday evening post front and continue into Sunday morning with the focus being near/east of the 850mb front/trough axis and north of the surface front near the coast or in the area along and east of I-35 from near Austin into AR. I am not overly confident in this placement of the rainfall axis and it could just as easily be displaced further southward or eastward, some of the latest models are trending more in that direction.

Grounds have dried some in the last few weeks and most rivers have returned to near normal flow with flash flood guidance for 3-hr for most counties in the 4-5 inch range. Feel the area can handle some decent rainfall amounts. While the nature of this system is slow moving and extended, there does appear to be some breaks between rounds of thunderstorms allowing rainfall to run-off. Over time grounds will saturate leading to greater and greater amounts of run-off and so the flood threat will increase the later we move in time (over the weekend).

Rainfall amounts look to average 2-4 inches across the area with isolated amounts of 4-6 inches. Could see a few locations go a little higher than that….especially up to the north closer to the HPC bullseye of 6-7 inches over NE TX. Will need to watch the trends of the next 24-36 hours closely and if the heavier rains look to focus more southward a Flash Flood Watch may be required.

[Srain]

Morning e-mail from Jeff:

Short wave approaching the area from the southwest early this morning sparking a few thunderstorms.

And so it begins….large upper level storm system has dropped into the SW US and is becoming cut off from the main upper level flow over the US. At the surface a strong cold front is surging through NW TX while ahead of this feature a strong 40-55kt low level jet extends from the western Gulf across much of eastern TX. Corpus VAD data showing winds just off the surface of 40-50kts including around 56kt on the 600am sounding around 2500 ft. Some of the wind energy has been mixing down to the surface in the developing thunderstorms around the Victoria area this morning. Storms over Calhoun County WSW to near Alice, TX appear to be developing under the core of the low level jet and strong moisture convergence with the aid of a weak mid level short wave. No meso scale models showed this development this morning. Storm motions are toward the ENE to NE or generally up the US 59 corridor, but storms have thus far been weakening as they move across Wharton into Fort Bend Counties. These storms will be capable of producing brief very heavy rainfall and very strong winds of 50-55mph as they transport down the strong wind energy just above the surface.

Cold front will cross the area tonight and then stall over the coastal waters Friday. A shallow dense cold air mass will filter into the region behind this front while the upper level storm system over the SW US remains stalled. This will result in tremendous Gulf moisture advection northward over the surface cold dome Friday-Sunday. Incoming flow off the western Gulf will be very moist with PWS of 1.5-1.7 inches being forced up and over the surface cold dome…an overrunning event. This pattern in itself will linger widespread rains behind the front, although the short term models are showing more scattered nature type stuff on Friday versus widespread constant rains. Past event have been more scattered and will trend toward that thought for Friday.

Where things really start to get interesting is in the timing of the short waves (disturbances) ejecting out of the main upper level storm to our SW. Each disturbance will move across the area from SW to NE over the weekend and work with the moist air mass, stalled surface front, and favorable upper level divergence to produce periods of showers/thunderstorms. Still looks like the 850mb front will stall and become oriented SSW to NNE from NW of Victoria to near College Station to Texarkana and along and east of this feature appears to be where the greatest threat for training thunderstorms may be over the weekend. It is one of these event that will have to be watched hour by hour to see where and for how long any cell training sets up. Models are not able to always grasp the meso scale banding and boundaries that can set up and produce very heavy rainfall in a local area.

While the red flags are there for a heavy rainfall/flood event with this set up, I am not confident in the location nor the duration of any sustained training heavy rainfall which is typically what causes the most problems in this area. Moisture levels nearing the +2 SD for this time of year along with excellent inflow of rich moisture off the western Gulf, stalled surface and mid level synoptic scale boundaries, upper level flow parallel to the boundaries, and broad 250mb divergence are all pointing to training heavy rains. However this does not appear at this point to be a continuous rainfall event for the next 72 hours, but instead rounds of thunderstorms every 4-6 hours as the disturbances mentioned above eject across the region. The question then becomes how long does the heavy rainfall last with each round and how long are the breaks between rounds to allow rainfall to run-off and additionally does the heavy rainfall hit the same area each round. None of these questions can be answered more than about 12 hours out in this type of a pattern so it becomes a watch and see type situation.

Will continue with widespread rainfall amounts of 2-4 inches across the entire area with isolated totals of 5-6 inches especially north of I-10 and west of I-45. A few locations over E and NE TX could see totals even higher by Sunday evening. Will need to keep a very close eye on rainfall totals over the weekend and the run-off that is being generated. Flash Flood Guidance is in the 4-5 inch range for the 3 hr time period for nearly all of our SE TX counties…while this is high now, rains today and Friday will greatly reduce these values and saturate grounds, so it will be the rains over the weekend that will need to be watched. Long duration of the event and widespread nature suggest some rises on area rivers are likely going into the late weekend and next week. Given the amounts of rainfall forecasted over a fairly large area could produce some rises on area rivers to near flood stage.

Severe Threat:

SPC has expanded their slight risk area overnight to include much of our northern counties (roughly north of HWY 105). With the front not reaching our area until after midnight, there appears to be only modest instability in place by that point to produce much in the way of severe storms. Isolated wind damage will be possible and a few hail reports, but widespread severe weather is not expected. Elevated thunderstorms in the cold air mass over the weekend could produce some hail.

Note: Temperatures will fall into the 50’s behind the cold front on Friday and with NE surface winds, clouds and rainfall through the weekend temperatures will likely be locked in the 50’s for much of the period.

SPC (Day 1) Severe Weather Outlook):