Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 4

[DFWWeather]

What time frame are you looking at with respect to the ULL that "lurks in the near future?"

 

I wouldn't get too carried away for winter precip in deep south Texas just yet. It still looks questionable on available moisture and depth of cold air even up here in DFW. Operational models are continuing to be warmer looking with each run for next week. The 0z ECMWF was not nearly as impressive with the event as the 12z run was yesterday. Furthermore, the GFS does not hang this energy back at all, so there is likely to be some kind of compromise on the timing of this feature. Overall, the GFS and esembles are deeper with the trough through next week, I suspect because they are not hanging has much energy back (ULL). The GFS is also trying to erode the cold a bit too quickly given the overall pattern.

[wxmx]

Pattern reloading, but with a more negative AO this time is starting to show in the long range models. Let's see if this time it works out.

[wxmx]

I wouldn't get too carried away for winter precip in deep south Texas just yet. It still looks questionable on available moisture and depth of cold air even up here in DFW. Operational models are continuing to be warmer looking with each run for next week. The 0z ECMWF was not nearly as impressive with the event as the 12z run was yesterday. Furthermore, the GFS does not hang this energy back at all, so there is likely to be some kind of compromise on the timing of this feature. Overall, the GFS and esembles are deeper with the trough through next week, I suspect because they are not hanging has much energy back (ULL). The GFS is also trying to erode the cold a bit too quickly given the overall pattern.

 

A progressive trough would make things colder for more, but a hanging back of energy, especially if the Pac ridge can pool enough cold air, can make things more interesting for a few. The Euro and CMC cut off the low, while the GFS and Ukie are more progressive, with just shortwave energy along the trough's base. The GFS ensembles are less progressive, with the op GFS being a bit of an outlier. Taking everything into account, and how the current pattern has worked out in the recent past, I'm leaning towards a cutoff low in NW MX.

[DFWWeather]

A progressive trough would make things colder for more, but a hanging back of energy, especially if the Pac ridge can pool enough cold air, can make things more interesting for a few. The Euro and CMC cut off the low, while the GFS and Ukie are more progressive, with just shortwave energy along the trough's base. The GFS ensembles are less progressive, with the op GFS being a bit of an outlier. Taking everything into account, and how the current pattern has worked out in the recent past, I'm leaning towards a cutoff low in NW MX.

 

I'm kinda leaning that way myself, but the question still remains is on depth of cold air. We have great pattern recognition for snow/ice at DFW next week, as I posted about earlier. We have one heck of a pattern in general coming up for cold weather, but I just don't see any major Arctic intrusions yet (by major I mean an Arctic surge cold enough to send DFW's temp well down in the lower teens or even single digits). However, I am liking the looks of both the 12z today GFS and ECMW 8 to 10 day 500 mb means (below/attached). Can really see how the cold can get cranking out of such a pattern!

 

 

[wxmx]

I'm kinda leaning that way myself, but the question still remains is on depth of cold air. We have great pattern recognition for snow/ice at DFW next week, as I posted about earlier. We have one heck of a pattern in general coming up for cold weather, but I just don't see any major Arctic intrusions yet (by major I mean an Arctic surge cold enough to send DFW's temp well down in the lower teens or even single digits). However, I am liking the looks of both the 12z today GFS and ECMW 8 to 10 day 500 mb means (below/attached). Can really see how the cold can get cranking out of such a pattern!

 

 test8.gif

 

Yep, agree, we attached the same image.

[wxmx]

18z GFS is a tad more progressive and colder, but the ensembles are also colder and there are only 2 more members that support the op progressive pattern. There's not much moisture, but the models that cut off a ULL are obviously more humid. To give you an idea of how much colder most ensembles and op are, all of them show <0C 850mb temps for my location, with the op, as always, being the warmer at -2C, and 1 member bringing down the 0C to around Tampico. OTOH, 12z CMC and Euro barely get the 0C 850mb isoterm to my location, so I'm not yet bought in with the colder solutions

[bubba hotep]

It will be interesting to see how this plays out in model land.  It seems like the GFS has been more progressive this whole winter (based purely on selective memory and that could be a completely false and ignorant statement) and that earlier in the winter the Euro was playing catch up and trending towards the GFS.  However, it seems like with the past few systems the more progressive GFS has had to play catch up and has trended towards the Euro. 

[bubba hotep]

In Houston for the next two weeks. I woke up to loud thunder and pouring rain this morning.

By the way I'll be joining you all in Houston permanently some time this Spring.

 

Moving to Houston?  Welcome to the area but I think DFW has more interesting weather than Houston

[Quixotic1]

Moving to Houston? Welcome to the area but I think DFW has more interesting weather than Houston

unless you're a tropical weenie!

[DFWWeather]

Lookout - McFarland Signature on GFS?

[Srain]

Morning e-mail from Jeff:

 

Cold moist pattern to establish over the area Sunday-mid week.

 

Gulf moisture will begin to return to the region today behind the Wednesday storm system. Should see an increase in cloud cover by this afternoon and the short term meso models are suggesting possibly a few showers drifting inland off the western Gulf. Better moisture advection gets going on Saturday as surface low pressure develops on an incoming front from the north. Expect an increase in showers across the area, but strong capping will preclude any thunderstorms. Could have to deal with a bout of dense sea fog along the coast if dewpoints creep above cold nearshore water temperatures tonight and on Saturday.
 
Cold front enters the area late Saturday and added lift from this boundary will produce a line of mainly showers and an isolated thunderstorm. Capping looks to hold strong until the boundary is able to lift the surface parcel enough to break through the warm layer. Instability is lacking and what meager amounts that are available are elevated, so a few thunderstorms will be possible, but no severe weather is expected. Front should exit off the coast by 600am Sunday morning.
 
Strong cold front will usher cold air into the region with temperatures in the 60’s ahead of the front falling quickly into the 40’s and 50’s behind the boundary. Additionally, the boundary will be shallow, extending vertically only 2000-4000 ft which allows 850mb winds to remain out of the south and southwest and pump Gulf moisture up and over the top of the cold surface dome…overrunning. This pattern supports a slow gradual lifting of the air mass over the region and expect widespread light to at times moderate rainfall to develop in the post frontal air mass Sunday-Monday. Rainfall amounts from Saturday-Monday will average .25-.50 of an inch with isolated totals of 1.0-1.5 inches.
 
Forecast for the middle to end of next week is more questionable as the ECMWF model closes off an upper level low over the SW US while the GFS is much more progressive and open with a trough shearing out across the plains. GFS would be a much drier pattern while the ECMWF would produce much wetter conditions. For now will continue with the overrunning cloud cover Tuesday-Thursday, but cut rain chances into the 30-40% range for this period and await better model agreement before going wetter or drier. Temperatures will remain cold through the entire period (Sun-Thurs) with highs in the 40’s/50’s and lows in the 30’s/40’s.
 
January 8-9 Rainfall Totals:
 It should be noted that the start of 2013 has been extremely wet across the region with many sites running rainfall surpluses of 2-4 inches and a few sites have already reached their monthly January rainfall totals.
 
 
BUSH IAH: 1.60
Hobby: 1.98
Galveston: 1.92
College Station: 4.10
Conroe: 3.57
Huntsville: 2.13
Tomball: 4.29
Sugar Land: 2.26
Pearland: 3.09
Angleton: 2.35
Palacios: 2.28
League City: 2.79
Bellville: 2.45
Brenham: 3.11
Crockett: 3.13
Edna: 1.13
El Campo: 1.98
Freeport: 2,61
Katy: 4.64
Madisonville: 4.51
Matagorda: 2.40
Richmond: 3.02
Wharton: 3.53
Port Bolivar: 5.00
Fulshear: 4.27
Snook: 4.15
Caldwell: 4.09
Bayou Vista: 3.44
1SE Edna: 2.82
Victoria: 2.03
Rockport: 1.86
Austin: 2.49
San Antonio: 2.53
Temple: 3.20
 
 
Rainfall for the Past 7 days (From the West Gulf River Forecast Center):

 

[bubba hotep]

What is that you say 12z GFS? You are folding?

[wxmx]

What is that you say 12z GFS? You are folding?

 

Which event? 14th-18th or an arctic outbreak after that? The 14th-18th looks very dry, so unless we get a ULL 100mi S of where's currently projected (N Sonora and Chihuahua), it will just be a week long of colder than normal temps, especially near the MX/TX border. For the arctic outbreak, I'm not folding, my time range is around the 25th to Feb 5th.

[DoctorMu]

Morning e-mail from Jeff:

 

Cold moist pattern to establish over the area Sunday-mid week.

 

Gulf moisture will begin to return to the region today behind the Wednesday storm system. Should see an increase in cloud cover by this afternoon and the short term meso models are suggesting possibly a few showers drifting inland off the western Gulf. Better moisture advection gets going on Saturday as surface low pressure develops on an incoming front from the north. Expect an increase in showers across the area, but strong capping will preclude any thunderstorms. Could have to deal with a bout of dense sea fog along the coast if dewpoints creep above cold nearshore water temperatures tonight and on Saturday.

 

Cold front enters the area late Saturday and added lift from this boundary will produce a line of mainly showers and an isolated thunderstorm. Capping looks to hold strong until the boundary is able to lift the surface parcel enough to break through the warm layer. Instability is lacking and what meager amounts that are available are elevated, so a few thunderstorms will be possible, but no severe weather is expected. Front should exit off the coast by 600am Sunday morning.

 

Strong cold front will usher cold air into the region with temperatures in the 60’s ahead of the front falling quickly into the 40’s and 50’s behind the boundary. Additionally, the boundary will be shallow, extending vertically only 2000-4000 ft which allows 850mb winds to remain out of the south and southwest and pump Gulf moisture up and over the top of the cold surface dome…overrunning. This pattern supports a slow gradual lifting of the air mass over the region and expect widespread light to at times moderate rainfall to develop in the post frontal air mass Sunday-Monday. Rainfall amounts from Saturday-Monday will average .25-.50 of an inch with isolated totals of 1.0-1.5 inches.

 

Forecast for the middle to end of next week is more questionable as the ECMWF model closes off an upper level low over the SW US while the GFS is much more progressive and open with a trough shearing out across the plains. GFS would be a much drier pattern while the ECMWF would produce much wetter conditions. For now will continue with the overrunning cloud cover Tuesday-Thursday, but cut rain chances into the 30-40% range for this period and await better model agreement before going wetter or drier. Temperatures will remain cold through the entire period (Sun-Thurs) with highs in the 40’s/50’s and lows in the 30’s/40’s.

 

January 8-9 Rainfall Totals:

 It should be noted that the start of 2013 has been extremely wet across the region with many sites running rainfall surpluses of 2-4 inches and a few sites have already reached their monthly January rainfall totals.

 

 

BUSH IAH: 1.60

Hobby: 1.98

Galveston: 1.92

College Station: 4.10

Conroe: 3.57

Huntsville: 2.13

Tomball: 4.29

Sugar Land: 2.26

Pearland: 3.09

Angleton: 2.35

Palacios: 2.28

League City: 2.79

Bellville: 2.45

Brenham: 3.11

Crockett: 3.13

Edna: 1.13

El Campo: 1.98

Freeport: 2,61

Katy: 4.64

Madisonville: 4.51

Matagorda: 2.40

Richmond: 3.02

Wharton: 3.53

Port Bolivar: 5.00

Fulshear: 4.27

Snook: 4.15

Caldwell: 4.09

Bayou Vista: 3.44

1SE Edna: 2.82

Victoria: 2.03

Rockport: 1.86

Austin: 2.49

San Antonio: 2.53

Temple: 3.20

 

 

Rainfall for the Past 7 days (From the West Gulf River Forecast Center):

01112013 Jeff image001.png

 

I win!

 

6.05 in    backyard 4 miles E of CLL airport (Easterwood)

[bubba hotep]

Which event? 14th-18th or an arctic outbreak after that? The 14th-18th looks very dry, so unless we get a ULL 100mi S of where's currently projected (N Sonora and Chihuahua), it will just be a week long of colder than normal temps, especially near the MX/TX border. For the arctic outbreak, I'm not folding, my time range is around the 25th to Feb 5th.

I was talking about the cutoff low for mid to late next week. Euro has been on it for a bit but the GFS kept sticking with the more progressive look. 12z GFS finally cuts it off.

[wxmx]

I was talking about the cutoff low for mid to late next week. Euro has been on it for a bit but the GFS kept sticking with the more progressive look. 12z GFS finally cuts it off.

 

Oh, yep, I was always on the cutoff low camp...but, while it might get a bit more moist atmosphere, there's little tropical connection. So the only hope is for the ULL to dig further south, but there's no support for that, so I guess it will be coldish and dry. Now the Canadian switched with the GFS and is the more progressive solution.

[DFWWeather]

Now the 12z ECMWF is much drier with the 12z GFS finally cutting off the ULL and trending wetter.

[Big O]

Which event? 14th-18th or an arctic outbreak after that? The 14th-18th looks very dry, so unless we get a ULL 100mi S of where's currently projected (N Sonora and Chihuahua), it will just be a week long of colder than normal temps, especially near the MX/TX border. For the arctic outbreak, I'm not folding, my time range is around the 25th to Feb 5th.

What are you seeing that supports an Arctic outbreak in the southern Plains?  It seems like the models are shunting most of the frigid air to the east and southeast in the longer range.  What gives?  I'm not suggesting you are wrong (as you are one of, if not, the most astute non-meteorologists on the board?  I'm just trying to wrap my head around it.  Thanks.

[DFWWeather]

What are you seeing that supports an Arctic outbreak in the southern Plains?  It seems like the models are shunting most of the frigid air to the east and southeast in the longer range.  What gives?  I'm not suggesting you are wrong (as you are one of, if not, the most astute non-meteorologists on the board?  I'm just trying to wrap my head around it.  Thanks.

 

He is seeing the northern hemispheric pattern ripe for such an event with Polar vortex south of Hudson Bay and the potential for a McFarland to develop out of this pattern with cross polar flow. Check out the image I posted from today's 0z 500mb 8 to 10 day mean right below. That would produce some frigid air. Furthermore, all the teleconnective indices that we use to forecast long range events are pointing to substantial cold across North America. However, the caveat is there is so much cold going across to Europe and Asia right now, it makes one wonder how much there will be to deliver in the extended. The GFS below shows some wicked cross polar flow with those height lines crossing the Arctic circle. The ECMWF (left) is not nearly as amplified below, but it is more amplified on today's 12z. Brrrr!

 

[Big O]

He is seeing the northern hemispheric pattern ripe for such an event with Polar vortex south of Hudson Bay and the potential for a McFarland to develop out of this pattern with cross polar flow. Check out the image I posted from today's 0z 500mb 8 to 10 day mean right below. That would produce some frigid air. Furthermore, all the teleconnective indices that we use to forecast long range events are pointing to substantial cold across North America. However, the caveat is there is so much cold going across to Europe and Asia right now, it makes one wonder how much there will be to deliver in the extended. The GFS below shows some wicked cross polar flow with those height lines crossing the Arctic circle. The ECMWF (left) is not nearly as amplified below, but it is more amplified on today's 12z. Brrrr!

I see that, but my fear is that the PNA ridge may situate itself too far east, thereby leading to more of a Mississippi Valley trough than one over the central CONUS.  While we would still get cold air, the coldest air would most likely be further east (if, but only if, the west coast ridge sets up shop further east).  Perhaps what we need out of the PNA is a neutral to slightly above neutral reading?  Thoughts?

[wxmx]

He is seeing the Polar vortex south of Hudson Bay and the potential for a McFarland to develop out of this pattern with cross polar flow. Check out the image I posted from today's 0z 500mb 8 to 10 day mean right below. That would produce some frigid air. Furthermore, all the teleconnective indices that we use to forecast long range events are pointing to substantial cold across North America. However, the caveat is there is so much cold going across to Europe and Asia right now, it makes one wonder how much there will be to deliver in the extended. The GFS below shows some wicked cross polar flow with those height lines crossing the Arctic circle.

Yep, PV in the HB is classic for C CONUS cold, more than the East Coast. Unless a very strong -NAO develops, which would dislodge the PV from the HB and move it closer to the NE, which some runs have shown...but even then, the PV progresses rapidly and redevelops in the HB.

 

Although a PV in the HB is good for N Plains cold, there needs to be a big ridge in the west coast to tap some arctic cross polar flow and deliver the goods to the south...if these 2 combine, it'll be very cold in our backyard...and if the west coast ridge connects to the arctic ridge, then it develops what is known as the McFarland signature, which would bring the freezer to most of the CONUS.

 

So the ingredients are there:

 

1. The MWW will send the AO to the tank. This is unanimously shown in all models in the mid and longer range, to different degrees. Confidence on this is high.

2. PV splits, with one piece in Siberia and one in Canada, which most models keep around HB on average. Confidence on this is moderate.

3. Big west coast ridge. Most models show anomalous high heights in this region, and they are supported by MJO phase 5-6 and GWO phase 4-5 (though this one is weak) with increasing GLAAM. Confidence is low to moderate.

4. The biggest question mark is if the pacific ridging will be strong enough (or the arctic ridging, or both) to link and deliver the mythic cross polar flow. Confidence is low, mostly because models have shown it just occasionally, and also because is naturally a low probability event.

 

Check all 4, and you'll have to keep your fridge door open to keep you warm.

[wxmx]

I see that, but my fear is that the PNA ridge may situate itself too far east, thereby leading to more of a Mississippi Valley trough than one over the central CONUS.  While we would still get cold air, the coldest air would most likely be further east (if, but only if, the west coast ridge sets up shop further east).  Perhaps what we need out of the PNA is a neutral to slightly above neutral reading?  Thoughts?

Yep, slightly above neutral PNA is the best for us...especially if the ridge is positively tilted. Phases 7 & 8 of the MJO would argue for a stronger PNA ridge...phases 6&7 would tend to keep it a bit west.

 

[Big O]

Thanks.

[Srain]

It certainly was cold while I was away in Taos this past week. A strong front arrived yesterday morning in ABQ with winds gusting to the 50mph range before my flight departed. Saw some -5 F up in Taos while I was there and much colder air is expected this week.

 

[Srain]

We may need to keep an eye on the Tuesday night/early Wednesday time frame for some light freezing drizzle across Central/NE Texas as the positive tilted trough and associated upper air disturbance moves E across Texas.

[DFWWeather]

12z op GFS finally in some sense of reality with polar vortex dropping into Great Lakes. Shiver me timbers - BRRRR!!!! Folks that is some wicked cold! McFarland anyone?

 

ECMWF vs GFS 12z 500 mb mean:

 

 

[wxmx]

At day 10 is nearly a McFarland signature, but I would like higher heights in AK...just like the day 12+ shows...very, very cold pattern

[wxmx]

It's hilarious how all models are flip flopping wrt how progressive the trough will be and if it can close a ULL or not.

[Srain]

It's hilarious how all models are flip flopping wrt how progressive the trough will be and if it can close a ULL or not.

Seems fitting. The guidance has struggled since December with these 5H vorts. Snow/sleet showers in Austin and the Northern part of SE TX up to Tyler/Shreveport anyone...lol

[Portastorm]

Seems fitting. The guidance has struggled since December with these 5H vorts. Snow/sleet showers in Austin and the Northern part of SE TX up to Tyler/Shreveport anyone...lol

 

I'm off to Home Depot for a snowblower!