SW LA/SE TX Winter 2012-2013

[vbhoutex]

Dicey weather in our near future? Jeff Lindner thinks it is a possibility.

Next storm system quickly arrives into the area Wed-Thurs with strong to severe thunderstorms possible.

Fast progressive upper air pattern will bring another upper level storm system and Pacific cold front into the area by Thursday. Cool front from last night has pushed into the NW Gulf this morning with a dry and cool air mass in place over SE TX. High clouds are already starting to stream ENE from central MX in response to the next digging trough out west. Front will stall over the NW Gulf today while moisture begins to return northward from both the Gulf and Pacific above the surface cold dome. Will see a rapid increase in cloud cover from SW to NE tonight as moisture surges northward above the cold dome. Skies will be cloudy be sunrise Wednesday with lifting of the incoming moist air mass over the cool dome producing periods of showers, light rain, fog and drizzle. Showers will become numerous by early afternoon as a lead short wave crosses the area helping to enhance lift. Additionally, the warm front will move northward and approach the coast by mid afternoon on Wednesday. Surface based instability appears limited, but there appears to be some elevated instability and thunderstorms may become more numerous as the day progresses near and north of the warm front. Not expecting much severe weather on Wednesday, but a few of the elevated storms could produce some hail.

As a surface low deepens over central TX on Wednesday night, the attached warm front downstream over the upper TX coast should progress inland and through much of SE TX by Thursday morning. Area will become under the influence of the warm sector, but also under the increasing influence of capping from the SSW. Approach of the main upper trough across NW TX into OK will push a cold front eastward across central TX and as this boundary encounters the warm and moist air mass east of I-35 expected thunderstorms to develop. Strong linear forcing is suggested indicating more of a line than discrete cells. However strong lift will also be overspread the northward moving warm front which should be along a line from near Temple to Lufkin Thursday morning. Convection will become increasingly surface based and the air mass will be highly sheared in the low level, so supercells with tornadoes will be possible along and near the warm frontal boundary which could be over our northern set of counties. One drawback for a significant severe weather outbreak appears to be limited instability with CAPE values of 800-1500 J/kg over the region. Low level shear is impressive however and storms that are able to root near the surface will have rotating updrafts.

South of the warm front across the warm sector and the rest of SE TX, the linear forcing along the advancing front combined with a strong upper level sub-tropical jet overhead should result in a line of thunderstorms or squall line to move across the area from W to E during the morning hours. There will be a severe threat with this line also…with the main threat being wind damage, but isolated tornadoes in any “notches” in the line will be possible given low level helicity values of 200-400 m^2/s^2. How far south this line of storms extends will depend on the intensity of the capping advecting NNE from S TX. Forecast models are not overly excessive with the cap, but time of day (early to mid morning) does not bode well for any heating as compared to yesterday when surface heating was able to weaken the cap and lift from a short wave enticed convection through the mid level warm layer. Will review the severe parameters again Wednesday AM as by this point there should be a decent handle on the threat and the most likely severe modes.

Cold front Thursday afternoon slows and stalls just offshore with clouds and possible showers lingering near the coast early Friday. GFS has come in wet on Saturday as this model amplifies another short wave and drops it across TX, but no other models currently suggest this scenario. For now will follow the dry guidance and keep skies partly cloudy and conditions dry unless the other major models begin to trend toward the wetter GFS solution.

[PTrackerLA]

Looks like the GFS and Euro both agree on freezing temperatures returning to the gulf coast next weekend. The 18z GFS and Euro would indicate temps possibly in the upper 20s here for at least two nights. Will be interesting to see how this evolves through next week.

[vbhoutex]

Looks like the GFS and Euro both agree on freezing temperatures returning to the gulf coast next weekend. The 18z GFS and Euro would indicate temps possibly in the upper 20s here for at least two nights. Will be interesting to see how this evolves through next week.

I had to laugh this morning when a local OCM mentioned the possibility of snow flurries in SE TX for next weekend. Not saying it will or won't happen but I have to look at the models a lot closer before any real confidence in the forecast can be had. JMHO
And after a quick look, I am still laughing. It does indeed appear that it will be cold for us for that time of year, but I don't know which model he was looking at to find flurries in SE TX. Figures we have a photo shoot with the granddaughters set for next Sunday.

[vbhoutex]

Radar and the fact the sun is out tell me that we have just had FROPA in W. Houston. Winds are starting to kick up out of the W also. Currently 64.4f. Will it start to drop?? BTW passage is about 2 hours ahead of schedule.

[PTrackerLA]

Sorry you guys got missed again VB. It's amazing how these systems 'juice up' as soon as they reach the Sabine River LA/TX border area. There was a local met years ago that used to always say that all weather starts or ends at the sabine river. Received about 1.4" last night with the warm front and the storms are really firing up upstream from us now. Could have a severe weather threat soon if these trends continue:

http://radar.weather.gov/radar_lite.php ... R&loop=yes

[vbhoutex]

Sorry you guys got missed again VB. It's amazing how these systems 'juice up' as soon as they reach the Sabine River LA/TX border area. There was a local met years ago that used to always say that all weather starts or ends at the sabine river. Received about 1.4" last night with the warm front and the storms are really firing up upstream from us now. Could have a severe weather threat soon if these trends continue:

http://radar.weather.gov/radar_lite.php ... R&loop=yes

We had a probably mile wide band of light rain come through just before fropa. I think the gauge has 0.02" in it if I'm lucky. I DO NOT LIKE THE TREND I am seeing so far this year!!

[BigB0882]

I think I heard that we had about 4 inches over the last 24 hours here in Baton Rouge.

[PTrackerLA]

I had nearly 3" at my house with the event so it's nice to see the sunny skies and cool temps. Still looks like we'll have a freeze on Saturday night.

[CajunMama]

We finally have a winter...for a day!!! It's 36 right now and is SUPPOSED to get down to 31. I don't know if we've gotten below freezing yet this year.

[vbhoutex]

Official low of 32f here in Houston this am with light frost around. Very late for a freeze for any of us along the Gulf Coast. I think I remember many years ago we had a freeze on March 20, but I remember that(and for that matter March freezes) only happening once in the 40+ years I have been in Houston. I'm sure there have been a few, but not more than that. I am ready for Spring NOW!!

[PTrackerLA]

Officially reached 30 degrees here which is pretty much the coldest we have seen all winter. There was a heavy frost as early as midnight last night. Should keep the grass from really greening up for a few more weeks.

[vbhoutex]

It has turned into a beautiful day here in Houston. Currently 67f and sunny. Warmed up a lot more quickly than I expected this morning thankfully since we had an 11 am photo shoot with the Granddaughters.

[vbhoutex]

Yesterday was shorts and tank tops. Today is:

Wind Advisory in effect today

Red Flag Warning in effect today.

Strong cold front currently crossing the area will bring very strong winds to the region today. Tight pressure gradient noted over central TX this morning will spill southward over the next few hours with winds rapidly increasing into the 20-35mph range behind a cold front. By mid morning mixing of stronger winds aloft toward the surface will result in wind gust to 40-45mph.

Given the very dry air moving into the region from the north combined with the strong and gusty winds, near critical fire weather conditions are expected from late morning through late afternoon. Fine fuels (grasses) continue to dry with a lack of recent rainfall and some areas especially west of I-45 and north of I-10 have yet to see significant spring green up increasing the potential for wildfire. Should a wildfire develop, strong winds will result in rapid and erratic growth and fast forward burn rates. Conditions appear most dangerous west of I-45 where the lowest RH and strongest winds will be found. Very critical fire weather conditions will be found over much of central TX into the coastal bend where several fires developed last Friday with more marginal conditions.

Dry and cold air mass will cover the region tonight with high pressure building overhead winds will weaken but not likely go calm. Lows will average in the mid to upper 30’s for most areas. High pressure slowly moves eastward allowing a return of SE winds by late Friday and a slow but steady warming/moistening trend through the weekend. NW upper level flow of late becomes increasingly more SW with time opening the door to disturbances moving NE out of MX and possibly interacting with increasing moisture to produce a few showers.

[Jagno]

I finally got my yard dried out enough to mow and now more heavy rains forecasted for tomorrow through Monday. I've certainly enjoyed the beautiful weather this week.

[vbhoutex]

Yep Jagno, the maps do show more on the way for you. Radars already showing a lot of virga in TX due to dry low levels.
Here is Jeffs take:

Changes underway across the region as the cool and dry pattern begins to break down.

A large upper level storm system over the western US this morning will slowly progress into the central and southern plains over the next 48-72 hours. Surface winds are already responding to the lowering pressures over the southern high plains with winds swinging around to ESE and by this afternoon SE. Recent frontal passages have worked over the Gulf of Mexico with a mass of dry air located over much of the Gulf, so it will take time for SE/S winds to return moisture into the region. Aloft winds have become increasingly SW over the last 24-36 hours with high level cirrus clouds and upper level moisture across the state. As moisture slowly deepens off the Gulf and SW flow aloft brings small disturbances across the area the chance of rainfall will be increasing. Do not expect rain today with dry low levels still in place, but do think there will be a chance for a few showers on Saturday as the moisture depth increases.

Best rain chances will come Sunday as the next cold front moves across the region and the main upper level system ejects into the plains. Models are in decent agreement on the front crossing the area between about 1000am Sunday morning and reaching the coast by early Sunday evening. Pesky capping in noted on the forecasted soundings over the southern parts of the area which makes me wary of how far south and how widespread development on the front will actually be. Recent events have not produced much weather south of I-10 due to this capping inversion and the slightly northward deflection of the storm track this late winter/early spring. Feel the best chances of rain and thunderstorms will be north of I-10 and a few storms in this region could be near severe levels especially after noon on Sunday when marginal surface heating will be maximized, but this does not appear to be a significant severe weather threat. Rainfall amounts will average .5-1.0 inch north of I-10 to near .25 of an inch around Matagorda Bay with lesser amounts south and west of there.

Another post frontal dry air mass will move into the region early Monday with clearing skies and cool temperatures. Lows in the 40’s and highs in the low 60’s will make it cool for the first few days of Spring Break.

[vbhoutex]

This may be my last post in the Winter thread, but we are expecting temps down into the upper 30s low 40s next week. Doing yard work today while it is in the 60s. If there is any persistent "Winter" weather I'll be here, otherwise it is over to the Spring thread. May even do a SE TX/SW LA Spring thread, if it isn't already there and I just haven't seen it.

[vbhoutex]

One last gasp at Winter tonight in Houston. Predicted low tonight for most of the Metro area 35-40 but there could be some outlying areas that get to the freezing mark. Then we head to 80f for a high by the weekend.

[PTrackerLA]

Was 40 when I got up this am with some good frosts on the roofs. This was after receiving 1.5"-2.0" of rain the night before depending where you were in the area. After such a wet start to the year it was nice to dry out over the past two weeks and the recent rain will keep things nice and moist for a while. Hopefully we can get more rainfall over the next couple of weeks for our friends to the west who I know could really use it.

[vbhoutex]

That would be much appreciated!!!

[vbhoutex]

Jeff Lindner's morning email:

Strong cold front will bring near record cold temperatures by the end of the week.

In a pattern that continues to repeat, another strong upper level storm system will cross the state on Thursday ushering in a strong cold front. Ahead of this feature a warm and muggy air mass is noted across much of eastern TX with dewpoints well into the 60’s and at some sites the lower 70’s. Warm layer of air aloft is keeping a cap on any convective chances with some slight potential especially on Wednesday of a showers or two moving inland off the western Gulf in the offshore flow. Onshore flow is also bringing in a large amount of haze/smoke from agriculture fires in Mexico. There will be little change to the pattern until Thursday when a strong cold front sweeps across the area.

Models have shown a general slowdown in the frontal timing with the boundary entering our W counties in the mid to late morning and moving off the coast toward the early evening. This paces the boundary across the region during maximum heating and during the greatest amounts of instability. As with the past front past week, the capping inversion held strong along the boundary allowing no development until the lift from the upper trough arrived during the overnight hours. Capping looks to be a problem with the upcoming front also, especially across areas south of I-10. Areas north of I-10 stand at least a decent shot of the cap being broken, and with good instability and strong shear, any storms that develop in this region will likely become severe. Hard to pin down the severe threat still over 48 hours out and will take a closer look tomorrow.

Post front air mass will be cold from mid April with lows both Friday and Saturday mornings falling into the upper 30’s and lower 40’s which is near record temperatures. Highs on Friday will only reach the mid to upper 60’s and only 70 on Saturday or roughly 10 degrees below daytime highs. The dry and cold air mass will feel much different than the current air mass in place.