SE TX/SW LA Winter WX - 2011-2012

[srainhoutx]

At 60 hours the colder air is surging to the Coast as heavier precip forms to our SW near the Coastal low/trough and overrunning starts throwing precip N into the colder air as the Upper feature drops down. Radar sim looks good as well. Looks like about an 6-10 hour event with a moderate precip for SE TX via the NAM...

http://www.nco.ncep.noaa.gov/pmb/nwprod ... loop.shtml

[PTrackerLA]

Would a pro-met mind chiming in on what we can expect in southern LA (Lafayette) based on the latest GFS? Will this be a similar situation as last December where snow makes it all the way to New Orleans?

Sure looks like a possible big event based off this image but I'm still not sure if this is the correct output. Look at the QPF over southern LA .







Thanks in advance for everyone's input!

[Stormcenter]

Looks like a big time winter event if there ever was one
for LA. in my opinion. But as always with these models
and predicting snow I'll believe it when I see it.

[vbhoutex]

I am now "all in" for this event. The model consistency is now too much to ignore imo. I was concerned if there was going to be enough moisture for this and the timing seemed a little off, but now everything appears to be in place for a winter precip.(snow) event for a large portion of TX including SE TX. and then moving into most of, if not all of LA. Still not willing to pop on amounts(final), but a good 2" seems possible in the Houston Metro area with higher amounts just to the W and NW of the metro area.

[wxman57]

Would a pro-met mind chiming in on what we can expect in southern LA (Lafayette) based on the latest GFS? Will this be a similar situation as last December where snow makes it all the way to New Orleans?

Sure looks like a possible big event based off this image but I'm still not sure if this is the correct output. Look at the QPF over southern LA .

Thanks in advance for everyone's input!

I think that you have a reasonable shot at seeing some accumulation of snow there (on grass/cars, not surface streets). Maybe an inch.

[wxgirl69]

I am now "all in" for this event. The model consistency is now too much to ignore imo. I was concerned if there was going to be enough moisture for this and the timing seemed a little off, but now everything appears to be in place for a winter precip.(snow) event for a large portion of TX including SE TX. and then moving into most of, if not all of LA. Still not willing to pop on amounts(final), but a good 2" seems possible in the Houston Metro area with higher amounts just to the W and NW of the metro area.

When do you think the snow (if we get it) will start coming down?

[severe]

When do you think the snow (if we get it) will start coming down?

Every prediction I've read says sometime starting around 12 noon. Possibly a rain/sleet/snow mix up until that time frame.

[PTrackerLA]

The 18z NAM is even more bullish on snow for south LA with the 0C 850mb line moving offshore in time for the heaviest precip. This model indicates snow for all but the mouth of the Mississippi! It's still hard to believe but the models keep building my confidence I'll at least see flakes in the air.

[srainhoutx]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
244 PM CST WED DEC 2 2009

...WINTER WEATHER POSSIBLE FRIDAY...

.DISCUSSION...
CLOUDS ARE EXPECTED TO ERODE THIS EVENING LEAVING MOSTLY CLEAR
SKIES BY THURSDAY MORNING. WEAK HIGH PRESSURE WILL DOMINATE AREA
WEATHER THROUGH THURSDAY. A REINFORCING SHOT OF COOLER AIR WILL
ENTER THE REGION FRIDAY NIGHT AS A STRONGER SURGE OF HIGH
PRESSURE SINKS SOUTH.

FRIDAY:
A COMPLICATED FORECAST IS ON TAP AND A NUMBER OF DIFFERENT
SCENARIOS COULD PLAY OUT. AN UPPER LEVEL TROUGH WILL APPROACH
TEXAS FRIDAY MORNING. WINDS ALOFT WILL BECOME SOUTHWEST AND OVER
RIDE NORTHEAST SURFACE WINDS. PRECIPITATION WILL DEVELOP EARLY
FRIDAY AS LIGHT RAIN. THE THERMAL PROFILE WILL COOL QUICKLY AND
THE RAIN WILL CHANGE TO SNOW. MAX TEMPS WILL OCCUR IN THE MORNING
AND FALL THROUGH THE DAY. FORECAST SOUNDINGS ARE IN GOOD
AGREEMENT THAT THE THERMAL PROFILE WILL BE COLD ENOUGH TO SUPPORT
SNOW. THE MOST SIGNIFICANT DIFFERENCE BETWEEN THE MODELS IS IN THE
AMOUNT OF AVAILABLE MOISTURE. THE CAN/ECMWF AND UKMET ALL FAVOR
KEEPING THE MOISTURE CLOSER TO THE COAST WITH LIGHT QPF TOTALS.
THE GFS AND NAM ARE FURTHER INLAND WITH SOME HEAVIER QPF TOTALS.
FORECAST SOUNDINGS SHOW AVAILABLE MOISTURE BETWEN 0.7-0.8 INCHES
WHICH IS RATHER ROBUST IN THIS TYPE OF AIR MASS. ALSO THE MODELS
SHOW A DECENT JET COUPLET AT 300 MB. SOUTHEAST TEXAS WILL LIE IN A
RRQ OF THE POLAR JET AND IN A LFQ OF THE SUB TROPICAL JET. THIS
SHOULD ALSO ENHANCE LIFT OVER THE AREA. THE JET DYNAMICS WILL BE
IMPRESSIVE AND COULD ACTUALLY BE THE KEY TO DETERMINING HOW MUCH
PRECIPITATION WILL FALL. BOTH THE GFS AND ECMWF HAVE SHOWN GOOD
RUN TO RUN CONSISTENCY BUT NEITHER MODEL HAS AGREED WITH THE
OTHER. IF THE ISENTROPIC UPGLIDE IS AS STRONG AS THE GFS/NAM
INDICATES...SNOW WILL ACCUMULATE. IF THE WEAKER ISENTROPIC UPGLIDE
PER THE ECMWF IS CORRECT...ONLY FLURRIES SHOULD BE EXPECTED. DUE
TO THE UNCERTAINTY...WILL REFRAIN FROM ISSUING ANY WINTER WEATHER
WATCHES OR ADVISORIES. THIS IS A DEVELOPING WINTER WEATHER
SITUATION AND THERE IS A GREAT DEAL OF UNCERTAINTY. KEEP UP WITH
THE FORECASTS!
MIN TEMPS ON SATURDAY MORNING WILL BE THE COLDEST OF THE SEASON. A
FREEZE WARNING WILL BE REQUIRED FOR SAT AM OVER THE ENTIRE CWA.
ONLY THE IMMEDIATE COAST WILL BE SPARED FREEZING TEMPERATURES. LOW
TEMPS WILL FALL INTO THE LOWER AND MID 20S OVER MOST OF THE
REGION. A BRIEF WARM UP IS IN STORE FOR SUNDAY BUT TEMPS WILL
REMAIN BELOW CLIMO. ANOTHER S/WV TROUGH WILL CROSS THE SOUTHERN
PLAINS ON SUNDAY AND BRING A CHANCE OF SHOWERS TO THE REGION. THE
FIRST PART OF NEXT WEEK LOOKS QUIET WITH COOLER THAN NORMAL
TEMPERATURES AS THE FLOW ALOFT GOES ZONAL. 43

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
304 PM CST WED DEC 2 2009

TXZ163-164-176>179-195>200-210>214-226-227-235>238-031100-
HOUSTON-TRINITY-MADISON-WALKER-SAN JACINTO-POLK-BURLESON-BRAZOS-
WASHINGTON-GRIMES-MONTGOMERY-LIBERTY-COLORADO-AUSTIN-WALLER-
HARRIS-CHAMBERS-WHARTON-FORT BEND-JACKSON-MATAGORDA-BRAZORIA-
GALVESTON-
INCLUDING THE CITIES OF...CROCKETT...TRINITY...GROVETON...
MADISONVILLE...HUNTSVILLE...SHEPHERD...COLDSPRING...LIVINGSTON...
CORRIGAN...ONALASKA...CALDWELL...LAKE SOMERVILLE...
COLLEGE STATION...BRYAN...BRENHAM...NAVASOTA...THE WOODLANDS...
CONROE...WILLIS...LIBERTY...CLEVELAND...DAYTON...COLUMBUS...
EAGLE LAKE...WEIMAR...SEALY...BELLVILLE...HEMPSTEAD...
PRAIRIE VIEW...BROOKSHIRE...HOUSTON...PASADENA...KATY...TOMBALL...
HUMBLE...WINNIE...MONT BELVIEU...ANAHUAC...EL CAMPO...WHARTON...
PIERCE...SUGAR LAND...MISSOURI CITY...RICHMOND...ROSENBERG...
EDNA...BAY CITY...PALACIOS...PEARLAND...LAKE JACKSON...ALVIN...
ANGLETON...FREEPORT...LEAGUE CITY...TEXAS CITY...FRIENDSWOOD...
GALVESTON
304 PM CST WED DEC 2 2009

...POSSIBLE WINTER WEATHER EVENT ON FRIDAY FOR SOUTHEAST TEXAS...
HIGH PRESSURE WILL BUILD INTO TEXAS THURSDAY NIGHT AND FRIDAY.
THIS FEATURE WILL BRING COLDER SURFACE TEMPERATURES AND STRONG
NORTH TO NORTHEAST WINDS. AN UPPER LEVEL LOW PRESSURE TROUGH WILL
APPROACH TEXAS EARLY FRIDAY. SOUTHWEST WINDS ALOFT WILL OVER RIDE
THE COLDER NORTHEAST SURFACE WINDS RESULTING IN CLOUDS AND LIGHT
PRECIPITATION. THE PRECIPITATION COULD BECOME HEAVIER DURING THE
AFTERNOON AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE REGION.
AT THIS TIME...IT APPEARS THAT LIGHT RAIN WILL DEVELOP EARLY
FRIDAY AND BECOME MIXED WITH OR CHANGE TO SNOW BY FRIDAY
AFTERNOON. THERE IS SOME POTENTIAL FOR SNOW ACCUMULATIONS OVER
PARTS OF SOUTHEAST TEXAS BY FRIDAY EVENING. A WINTER STORM WATCH
OR WINTER WEATHER ADVISORY MIGHT BE ISSUED LATER TONIGHT OR EARLY
THURSDAY IF SNOW ACCUMULATIONS ARE EXPECTED.

THIS SCENARIO REMAINS RATHER UNCERTAIN SINCE THERE IS STILL SOME
QUESTION AS TO HOW MUCH MOISTURE WILL BE AVAILABLE FOR WINTRY
PRECIPITATION. FORECASTERS WILL CONTINUE TO MONITOR FORECAST DATA
AND MAKE CHANGES AS NECESSARY. RESIDENTS OF SOUTHEAST TEXAS ARE
ENCOURAGED TO MONITOR THE FORECAST AND LOOK FOR UPDATES CONCERNING
THE WINTER WEATHER THREAT.

[Roxy]

I am now "all in" for this event. The model consistency is now too much to ignore imo. I was concerned if there was going to be enough moisture for this and the timing seemed a little off, but now everything appears to be in place for a winter precip.(snow) event for a large portion of TX including SE TX. and then moving into most of, if not all of LA. Still not willing to pop on amounts(final), but a good 2" seems possible in the Houston Metro area with higher amounts just to the W and NW of the metro area.

woohoo, I love you vbhoutex.

[MGC]

Just checked the NWS forecast for the MGC....rain/snow mix Friday night! Possibility of snow Dec 5th? We broke the record last winter for earliest snow here on the coast, who would have thought it might only last less than one year. Anyway, bring on the white stuff!!!!....MGC

[gboudx]

Here's an update for you guys from jeff.

Increasing confidence in snow event on Friday for SE TX.

With temperatures forecast to fall to or below freezing during the day on Friday accumulations and dangerous travel conditions are possible by Friday afternoon.

There has been little change today with respect to model progs of the upcoming event. 12Z GFS is a little more wet along with NAM with ECMWF and CMC the driest. GFS solution would produce some significant accumulations while ECMWF would be flurries. One question appears to be answered and that is it will be cold enough for snow. All soundings show a classic snow profile by midday Friday as strong arctic cold air advection overspreads the entire region bringing the low levels to and below freezing. Will start the day with surface temps. in the upper 30's falling toward 30 by late afternoon and the upper 20's by evening. I am very tempted to lean toward the wetter solutions given the consistency of the GFS and NAM and the fact that the NAM is usually the drier model. However, will hold off on getting too carried away with the moisture as the greatest amounts may remain just offshore or along the coast.

Friday:

Strong dynamic lift arrives by late morning with light rain developing from SW to NE across the entire region. NW counties will likely go quickly to snow with the rain/snow line dropping SE over time during the afternoon hours as the lows level cool. Strong lift may help to overcome the lack of good moisture amounts and such situations do not require a lot of moisture any how.

Accumulations:

A tough call as intensities will play a big role here and that depends on moisture available. Will go with a dusting to 1 inch north of I-10 with much of this melting on impact early on. As surface temperatures fall during the day...will begin to see accumulations on grassy surfaces, rooftops, and elevated roadways. S of I-10 change over will take longer and may be delayed until Friday afternoon resulting in less accumulation if any. Any meso scale banding or periods of heavy snow could bring a quick 2-4 inches of accumulation and this would impact not only elevated surfaces but also surface streets.

Impacts:

We are close enough to the event with enough confidence to be concerned with impacts. Given the surface temperature forecast to fall to freezing, snow accumulation, slush, icing of bridges and overpasses appears possible if not likely by Friday afternoon N of I-10. Any periods of heavy snow could accumulate on area surface roads. Expect a heavy wet snow with decent water content and with trees still heavily leaved the weight of the snow could bring down some limbs on to power lines especially with the expected strong NW winds Friday evening.

Aviation travel will experience issues with possible icing at terminals and taxi-ways. Aircraft control surface may ice and be required to de-ice before departing the terminal gate forcing long delays. Reduced visibility and very low ceiling will also delay both incoming and outgoing traffic.

Actions:

TXDOT will begin applying de-icing agent to the major freeway flyovers and overpasses Thursday morning. Focus will be on I-45 N between Beltway 8 and Hardy Toll Rd, US 59 N between Beltway 8 and the San Jacinto River, US 290 overpasses from HWY NW to Hempstead, and the high Beltway 8 interchanges. This agent helps raise the freezing level of water to a degree to help prevent freezing of overpasses when air temps are near the freezing mark. TXDOT and local counties are staffing for sanding operations to begin Friday if needed if bridges begin to glaze over.

Freeze:

Will see temperatures fall below freezing Friday afternoon and bottom out in the upper 20's Saturday AM. Some locations could fall into the mid 20's. This will require a freeze warning for near all areas as this will be the first killing freeze this winter. Additionally, some locations could be at of below freezing for 8-10 hours increasing the risk of damage to tender vegetation. This does not appear to be a pipe threat, but any exposed outside pipes should be protected.

Forecast Confidence:

Forecast confidence while increasing is really no greater than 50% at this time that snow will fall and accumulate. Several factors must combine just right and at the right time for this event to actually be an event. Confidence is close enough to at least start to consider Winter Storm Watches. Cannot emphasize enough the small scale factors that can make a hugh difference and some of these will not be resolved until Friday morning.

[JenBayles]

Oh crap on TOAST! Why do these things always happen at the worst possible times? My 89 year old mother-in-law is driving in with our cousin from Seguin on Friday. Now, probably not such a good idea. I see Seguin already has a 70% chance of snow. Then I have to get Mom in to the hospital for day surgery that doesn't even start until 1:00. If she has to stay overnight they'll have to put her in restraints with a gag or just shoot her and put her out the staff's misery. D****MIT!

[srainhoutx]

Oh crap on TOAST! Why do these things always happen at the worst possible times? My 89 year old mother-in-law is driving in with our cousin from Seguin on Friday. Now, probably not such a good idea. I see Seguin already has a 70% chance of snow. Then I have to get Mom in to the hospital for day surgery that doesn't even start until 1:00. If she has to stay overnight they'll have to put her in restraints with a gag or just shoot her and put her out the staff's misery. D****MIT!

Goodness Jen. If it's not one thing it's another. Looks interesting to say the least. Could go either way for us in SE TX, but S Central TX "could" have some issues early on Friday. Just my thoughts of course.

[vbhoutex]

I am now "all in" for this event. The model consistency is now too much to ignore imo. I was concerned if there was going to be enough moisture for this and the timing seemed a little off, but now everything appears to be in place for a winter precip.(snow) event for a large portion of TX including SE TX. and then moving into most of, if not all of LA. Still not willing to pop on amounts(final), but a good 2" seems possible in the Houston Metro area with higher amounts just to the W and NW of the metro area.

When do you think the snow (if we get it) will start coming down?

Areas further from the coast(N of I-10) will probably start changing over by noon-2pm with areas closer to the coast changing over later in the afternoon. Still a little iffy on how much accumulation we will have but at least enough to cover the grass pretty well will not be a surprise based on the current modeling.

[JenBayles]

You got that right srain. I wake up every morning expecting the worst these days, and it usually gets delivered.

Cuz has 4 horses and 19 dogs. Yep, nineteen. A neighbor can take care of them but not easily if she has to turn off the water to avoid burst pipes. I wouldn't worry about them driving here so much except that most people here don't know how to drive in rain much less ice/sleet/snow.

Mom has a certain amount of dementia anyway, and ANY change in her routine sends her spinning. Throw in a power outage and she's off her nut completely screaming at the poor Centerpoint folks over the phone every 20 minutes. In between, she screams at all her children on the phone. That goes on until it comes back on, whereupon she loudly congratulates herself for "getting the power restored."

One good thing: after the flood we ran a gas line to the kitchen (gas everywhere else in the house BUT the kitchen) and now have a gas range/ convection oven. With that and the firewood fully stocked, we're just fine with no power for a few days. I only wish I could kick back here at S2K all day and watch the even unfold from here!

[attallaman]

Will all those overpasses in and around the Houston area possibly freeze over?

[srainhoutx]

Will all those overpasses in and around the Houston area possibly freeze over?

Saturday night looks very cold by normal SE TX standards. Depending on snowcover across the area, mid 20's are a possibility IMHO. We shall see.

[attallaman]

Will all those overpasses in and around the Houston area possibly freeze over?

Saturday night looks very cold by normal SE TX standards. Depending on snowcover across the area, mid 20's are a possibility IMHO. We shall see.

Did you say the mid 20's? When it gets that low here we're advised to let our faucets drip pencil lead thin. With lows in the mid 20's that would seem like a good time to put a log on the fire, maybe 2 and sit nearby sipping on some warm egg nog and have a slice or two of Harry & David fruitcake for those who like fruitcake.

[wxgirl69]

Will all those overpasses in and around the Houston area possibly freeze over?

Saturday night looks very cold by normal SE TX standards. Depending on snowcover across the area, mid 20's are a possibility IMHO. We shall see.

Did you say the mid 20's? When it gets that low here we're advised to let our faucets drip pencil lead thin. With lows in the mid 20's that would seem like a good time to put a log on the fire, maybe 2 and sit nearby sipping on some warm egg nog and have a slice or two of Harry & David fruitcake for those who like fruitcake.

Oh my..We may be in the 20's saturday?????