SE TX/SW LA weather: Much cooler and WET after Tuesday

[srainhoutx]

Keep an eye on early next week. That front may infact mean business. Just beyond that some real Arctic Air maybe head our way.

Edit to add an update from Jeff...

Fairly quite weather for this upcoming week with a dry but cool Thanksgiving shaping up.

Stagnant surface flow off the Gulf this morning allowed for widespread dense fog in the rural areas. Will see moisture increase tonight and early Tuesday ahead of our next cold front. This front should arrive in the late morning to early afternoon hours on Tuesday with a slight chance of rainfall. Moisture return is meager and best dynamics are well north over KS and OK…still may be able to squeeze out a line of showers and a storm or two.

Cold air advection onsets late Tuesday with a secondary shot arriving late Wednesday. Overnight lows in the 40’s (lower 40’s) and highs in the upper 50’s to lower 60’s will be experienced Wednesday–Friday under mainly sunny skies.

Next big storm system arrives into the west coast late this week and begins its eastward advance toward the weekend. Gulf moisture begins to return northward Saturday with a warming and moistening trend. May have even moisture in place by Sunday for a few showers. Main event should arrive on Monday with widespread rains followed by much colder temperatures.

Impressive rains fell last Thursday/Friday over the middle Texas coast:

ROCKPORT (7 AM) 10.06 INCHES
ROCKPORT AIRPORT 9.94
ROCKPORT 2 NORTH (8 AM) 9.29
ARANSAS PASS 8.42
MATAGORDA ISLAND 7.20
BEE COUNTY (8 AM) 6.80
WOODSBORO (7 AM) 4.41
REFUGIO (8 AM) 4.24
PORTLAND (7 AM) 4.20
INGLESIDE 4.08
PORT ARANSAS (2 PM) 4.00
AUSTWELL (9 AM) 3.99
PORT ARANSAS 3.96
GUADALUPE VICTORIA 3.60
CORPUS CHRISTI NAVAL 3.56
MATHIS (6 AM) 3.50
BEEVILLE (7 AM) 2.93
FLOUR BLUFF (8 AM) 2.89
MCCAMPBELL 2.83
CORPUS CHRISTI OSO BAY (7 AM)2.70
SCHROEDER 2.39
GOLIAD 2.18
VICTORIA AIRPORT 2.15
CORPUS CHRISTI AIRPORT 1.83
GEORGE WEST 1.75
COTULLA 1.53
LAREDO 0.84

[Flyinman]

Thanks, would be nice to have our 1st week in December cold. Also, glad to see some of those arease catching up in rainfall.

[srainhoutx]

E-mail from Jeff this morning concerning the Cold Front today as well as the Stronger Canadian Cold Front and possible Severe Weather threat at the end of the Thanksgiving Holiday Weekend...

Strong cold front blasting into SE TX this morning.

Numerous thunderstorms have developed along the coastal counties as strong lift from an approaching short wave interacts the deeper moisture advection in that region. Storms have been training ENE from Matagorda Bay into Brazoria County and this should continue for the next 2-3 hours before the cold front pushes the activity offshore. Will need to keep an eye on rainfall totals in case they start to get out of hand with the training…this area was hardest hit last Friday with 3-5 inches of rainfall. Cold front is through CLL and hauling SE at 30kts or better. Front should clear the metro area by 900am and off the coast before noon. Upstream NC TX temps. in the mid 40’s and dewpoints in the low 30’s with gusty NW winds bode for a rapid temp. fall even as skies clear. Expect temps. to fall into the 50’s this afternoon under developing cold air advection regime.

Little weather to speak of after today as cold clear high pressure builds over the region through Friday promoting lows in the lower 40’s and highs in the 60’s through Friday under mostly sunny skies. Secondary cold surge will arrive Thanksgiving day keeping cool northerlies in place. N and NE counties may flirt with freezing early Friday morning.

Big changes begin by late Friday as a deep long wave trough develops over the western US. Lowering pressures over MX/NM will result in increasing southerly winds late Friday and really ramping up on Saturday. Impressive jet dynamics (110-120kts) come to bear across the region by Sunday as powerful short wave crosses the state. Modified polar boundary surges southward as the trough in the west moves into the plains sending a strong cold blast into TX. I am leaning toward the faster and stronger solution with thunderstorms Sunday…some severe and then very windy and cold Monday. GFS progs 850mb 0C line to plunge into the northern Gulf waters…with skies clearing and likely very low dewpoints in place freezing temps. will be likely next Monday night. Plenty of time to fine tune the numbers for any freeze impacts. GFS depicts a highly progressive flow the first week of December with cold air in place and lots of moisture overrunning…then again it showed that for this week…and while it may have the cool air temp. correct besides today there is limited rain chances.

[srainhoutx]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1000 AM CST THU NOV 26 2009

.DISCUSSION...
HIGH PRESSURE OVER THE STATE...CIRRUS MOVING INTO THE SW PORTIONS
OF THE STATE AND CREEPING INTO SETX THIS TURKEY DAY MORN. THE DRY
AIR/SUBSIDENCE ACROSS THE AREA HAS MANAGED TO GOBBLE UP MOST OF
THE CIRRUS IN SETX. NO CHANGES PLANNED TO CURRENT RECIPE FOR THE
WEATHER OVER SETX THAT PREVIOUS SHIFT HAS COOKED UP. THE DRY AIR
OVER THE REGION WILL DEPART FRIDAY NIGHT AND EARLY SATURDAY AS
HIGH MOVES EAST AND RETURN FLOW DEVELOPS. SO TODAY SHOULD BE A
GOOD OPPORTUNITY TO GET YOUR FILL OF SUNSHINE AND RELISH THE FALL
WEATHER.

[stormcloud]

Low clouds moving northeastward on the back side of low. Limited sunshine the rest of the day here SE TX. Further down the road, models still are advertising daytime highs only staying in the 40's Wednesday.

[vbhoutex]

Low clouds moving northeastward on the back side of low. Limited sunshine the rest of the day here SE TX. Further down the road, models still are advertising daytime highs only staying in the 40's Wednesday.

I've been looking at the models and seeing that also. As usual they are still wavering a little on how far South and how deep this cold air is initially going to be. With still very little snow cover to our North, all the way to Canada, I am tending to think that this cold shot may not be as strong as shown now due to modification from no snow cover. Of course, cloud cover can play a roll in that too since there won't be as much daytime heating especially if it is a shallow cold air mass. Any thoughts?

[stormcloud]

Evaporative cooling will play a part in our high temperatures both Tuesday and Wednesday. When the precip ends and cloud cover will also play a role. As for overnight temperatures, it appears they will be seasonably cool.

[southerngale]

34° for a low overnight Thursday, 44° for a low overnight Friday.. warming up in my flannel jammies, and last night I was out shopping in shorts. SETX weather for ya!

[vbhoutex]

Unless I am reading the models incorrectly temps are going to be on a downward slide for a while here in SE TX. I don't see any major cold snaps yet, but a definite cooling trend to a point where I may be using the word cold more often than not. Now if a man were to dream and the snow God's can be appeased(any volunteers?), maybe we could have another December miracle. Hey, I can dream can't I? Seriously though it does appear that we are not going to warm up a whole lot after this initial push of cool/cold weather for SE TX.

[srainhoutx]

I agree David. Way too many signals via guidance that this front will start the trend to a colder pattern. The Sub Tropical Jet looks to offer a disturabance about every 5-7 days just as the Arctic/Canadian airmasses drop S. Now is we can just get a bit of snow cover to our N we may be in business.

[Yankeegirl]

Im ready for the cold weather!! Where is it??! I want it NOW!

[vbhoutex]

Im ready for the cold weather!! Where is it??! I want it NOW!

Is tomorrow soon enough? Of course what we consider cold and you consider cold may be two different things.

[JenBayles]

Anything below 50 with high humidity and wind qualifies as miserably cold for me.

[jasons2k]

Anything below 50 with high humidity and wind qualifies as miserably cold for me.

I'm on the same page as you Jen

[jasons2k]

And so the real fun begins...

Personally - very excited about the snow prespects for Friday, but I'm dreading the threat of "bitter cold" next week:

Numerous issues to contend with this morning!

Confidence starting to grow for significant winter precipitation across Texas Thursday night–late Friday (See detailed section below)

Strong storm system to affect the area today into early Wednesday.

Arctic air mass to arrive Thursday into the area.

Today-Wednesday:

Cold upper storm system over N Mexico will move eastward today while NW Gulf surface low develops and tracks along the TX coast. Widespread rains along the coast will gradually build inland today with numerous coverage ongoing by afternoon into the evening hours. Surface low deepening over the NW Gulf will bring increasing NE winds to the coastal and offshore areas today with tides increasing. Upper storm crosses TX tonight with greatest lift coming to bear in the 600pm to 300am time period. Expect widespread rains with perhaps a clap of thunder or two. Rains will end from west to east early Wednesday as the low begins to shift east of the region.

A good widespread 1” of rain will be possible with higher totals near the coast. Along the coast the increasing ENE to NE wind will result in water level rise of 3.0-4.0 feet total producing some coastal flooding at high tide this afternoon from Rockport into SW LA. Bolivar is once again to most troubled spot with a 3.5 tide forecast at Port Bolivar…which may flood HWY 87. Winds will turn N Wednesday as the surface low moves into SC LA allowing tides to fall.

Thursday:

Departing storm system allows a dump of cold arctic air into TX Thursday. Blocking is gradually developing over the higher latitudes of Alaska and NW Canada and while the pattern is not in full place by Thursday…there is enough to send a cold shot deep into TX. GFS shows a large 1040mb high building southward with very cold air in the entire profile by Thursday evening. Will undercut highs by several degrees and show only the upper 40’s even with some sun on Thursday under strong cold air advection pattern.

Thursday night-Friday night:

Forecasting nightmare at hand for this period as GFS and now other models show a significant short wave moving across the region with the cold air in place producing widespread and at times heavy frozen precipitation. The potential comes from a strong short wave that drops out of the central Rockies and then deep into TX Friday with rapid moisture advection pouring into the cold air mass. Cross sections support all snow by early Friday morning as strong cold air advection in all levels is noted. The pattern reminds me more of a polar clipper system in the Midwest than a true winter storm by TX standards..I believe if my memory is correct we had something similar in February of the late 1990’s that produced trace amounts of snow at KIAH and around an inch over our NW counties. Main issue I have is not the cold air, but the amount of available moisture…the upper air pattern is a dry one…but then it does not take much moisture in such a cold air mass to produce precipitation and lots of it. Given 00Z ECMWF now trending toward slightly more moisture and 00Z NAM/GFS nearly identical cannot deny the fact that snow is possible…this is the 3rd run in a row for the GFS showing significant snow and the other drier models are starting to trend in that direction!

Profiles support all snow nearly all counties Friday morning with the exception being our SW counties where profiles and critical thickness support a rain/snow mix and then change over to all snow by mid morning. GFS and NAM show 0C 850mb line reaching the Gulf waters on Friday which would help bring the frozen precipitation to the coast and offshore. NWSFO at Austin/San Antonio and Houston/Galveston along with the section for Victoria have all reluctantly placed 30-40% snow chances in for Friday. If the GFS is correct chances will be closer to 80% with some areas of significant accumulation.

Hate to even attempt to tackle any kind of accumulations this far out and with so much uncertainty and the fact that I do not know if I believe it will snow two years in a row in Houston and so early in the season…would be a record! Given a 10-1 ratio would suggest anywhere from 1-10 inches with the 5-1 ratio showing about 1-8 inches. Do not foresee surface temperatures below freezing Friday morning, but the onset of snow could/will result in evaporative cooling and wet bulb cooling as cold air advection continues…allowing temperatures to fall toward freezing where snow will be falling. This wet bulb cooling effect would be very similar to the historical Christmas Eve 2004 snowstorm where temperatures started in the lower 40’s and cooled to near or just below freezing in the snowfall area allowing those historical accumulations.

As one can imagine with any kind of winter weather event this far south…the uncertainty is very high and forecast confidence extremely low…we could end up cold and cloudy or we could have some significant snow.

Extended:

Upper air blocking looks to lock in place in the form of a high latitude Rex block over portions of Alaska and W Canada. GFS builds a massive 1060mb arctic dome and unleashes it into the US with a bitter outbreak of very cold air across the US next week. If even a portion of this event unfolds some serious cold will be headed southward next week. Southern stream remains active and will support additional storm systems and moisture with this potentially cold air mass.

[srainhoutx]

Jason, we been having some interesting discussions in the Winter Weather thread. Even wxman57 has been posting "locally" as well as the TX Winter Weather thread. Looking at the trends, shades of 1973 sure look to be setting up. Jeff points out the active STJ. That played a big factor as well as shortwave energy in 73 for multiple snowfalls in Houston. 3 to be exact.

[jasons2k]

Heh - 1973 was the year I was born - it's my lucky number

[vbhoutex]

Jason, we been having some interesting discussions in the Winter Weather thread. Even wxman57 has been posting "locally" as well as the TX Winter Weather thread. Looking at the trends, shades of 1973 sure look to be setting up. Jeff points out the active STJ. That played a big factor as well as shortwave energy in 73 for multiple snowfalls in Houston. 3 to be exact.

IIRC, they were Jan. 16, Feb. 9, Feb. 16 or very close to those dates. That was an incredible winter! I was newly married and we had a blast playing in the snow. Great snuggle weather too!!

[srainhoutx]

Jason, we been having some interesting discussions in the Winter Weather thread. Even wxman57 has been posting "locally" as well as the TX Winter Weather thread. Looking at the trends, shades of 1973 sure look to be setting up. Jeff points out the active STJ. That played a big factor as well as shortwave energy in 73 for multiple snowfalls in Houston. 3 to be exact.

IIRC, they were Jan. 16, Feb. 9, Feb. 16 or very close to those dates. That was an incredible winter! I was newly married and we had a blast playing in the snow. Great snuggle weather too!!

The wild thing was 6-8 inches across eastern areas of the Metro with the January event. I will never forget the shock that one OCM (Doug Johnson) at that time expressed and Joe Sobel on the radio going nuts. Great memories.

[Tireman4]

I remember the snow events of 1973 well. I was in second grade and loving it.