Texas winter wx thread (2009-2010)

[iorange55]

Hm the 06z might be trying to pick up on something....

[Portastorm]

Hm the 06z might be trying to pick up on something....

Referring to the moisture lurking around west Texas/New Mexico at about 96 hours?

[wxgirl69]

I see we have a 40% chance of rain/sleet for Thursday!!!!!!!!! and Beaumont 40% sleet/snow!!!!!!!! When I say we, I am talking about Deer Park..

[wxman22]

Hm the 06z might be trying to pick up on something....

Yep i noticed that too,also the CMC still shows the disturbance pushing through after the front....

[Portastorm]

I'm a bit surprised at how warm the NWSFOs forecasts are for my area. Austin/San Antonio says a forecasted high in Austin on Thursday is 36 (which albeit may occur at like 12:05 am before the front arrives) and 34 on Friday. The Fort Worth office has Lampasas with a high of 33 on Thursday and 36 on Friday.

The 0z and 6z GFS show temps at or below freezing for both areas for at least 36 hours. Strange.

Edit update: Actually it is not that strange. Looks like they are following the grid numbers (GFS MOS). Figures.

[srainhoutx]

Overnight runs were very intereting. I urge everyone to get their plan of action for a long duration freeze event underway early this week before the Arctic Blast arrives. Those in the Southern half of TX need to be mindful of below freezing temps for 60+ hours N of the Coastal Areas. Also Wind Chills in the -5 to 10 above freezing will likely be common behind the front, if not lower further N into late Friday as well. Preparations need to be completed before the rains begin on Tuesday night/Wednesday if at all possible. Some guidance suggests post frontal Wintry Weather as well and will need to be monitered closely the next couple of days. What falls will likely freeze and remain frozen after the front passes and create Hazardous Conditions across TX. Please Stay Tuned!

[txagwxman]

Just let ur faucets drip (do middle so both warm/cold drip)...we did during the 1989, and 1983 freeze, and we were fine...wrap up exposed pipes outside.

[gboudx]

From jeff this morning:

Widespread Freeze expect tonight.

Coldest air in over 10 years heading for the area by Thursday.

Hard Freezes likely Friday-Sunday mornings.

Discussion:

Polar front moved across the region overnight with low clouds lingering this morning. Moisture trapped below the frontal inversion should keep mostly cloudy skies in place through the early afternoon hours. With clouds and cold air advection, will need to lower high temperatures into the upper 40’s. Upstream air mass is cold and large snow pack over the central US is allowing little modification of this air. Hence will also need to go colder tonight and this places our NE counties on the fence for a hard freeze (25 degrees or colder for 2 hours). Metro Houston should fall into the upper 20’s to lower 30’s and in the mid 30’s along the beaches. Would not expect any serious issues with this cold as it has already been colder back in early December.

Tonight will be a small taste of what is to come. Upper air pattern undergoes significant amplification this week with a bitter cold air mass over NW Canada being unleashed southward into the US. Massive 1055mb surface high enters the US over Montana Tuesday and plunges due south down the plains through the Gulf of Mexico and into mainland Mexico. Will go with the fastest model guidance on frontal timing as once this dense very cold air begins to move…little is going to stop it. Will show the arctic boundary blasting through the region Thursday before sunrise…and it will be downhill from that point on. Highs in the 40’s prior to the front will tumble into the upper 20’s by early evening under strong NW winds of 20-30mph. Wind chills will fall into the teens over most of the area. Skies will clear out Thursday PM, but winds should help the temperatures from getting out of control by Friday morning…although a hard freeze is likely along and N of US 59 by Friday morning. Latest guidance only shows highs breaking about 35 for a few hours on Friday and locations N of HWY 105 may remain below freezing all day. Massive arctic ridge builds overhead Friday night with clear skies and light winds…there appears to be nothing to stop the bottom from falling out on the temperatures. Lows in the upper teens looks likely N of I-10 with near 20 at IAH and freezing temperatures to the beaches. Will only recover into the upper 30’s for a few hours on Saturday before the temps. tank again Saturday night with the arctic high remaining in control. Hard freeze most locations again Sunday AM. Plenty of time to fine tune the lows for Friday-Sunday mornings.

Some locations (mainly N of HWY 105) will likely see 36-60 hours of sub-freezing temperatures from Thursday PM- Sun AM. Intensity and duration of this event has not been seen in SE TX since IAH fell to 19 in 1996…prior to that one must go back to the snow/cold air outbreak of December 1989 when IAH fell to its all time record low of 7. Freezing temperatures will be felt even across deep south Texas with damage likely to the citrus crops in both Texas and Florida.

Residents across the region should begin to prepare for this significant cold air outbreak. Exposed outside pipes should be wrapped as temperatures in the 10’s/low 20’s will cause some issues along with the long duration of the event. Temperatures of this magnitude will kill any un-protected tropical vegetation…and even protected vegetation may have some serious issues. Heavy irrigation of the ground soils prior to the event and then multiple layers of coverings may help mitigate some of the damage. Pets and livestock will also need protection. With wind chills falling to dangerously low levels into the low teens if not the single digits plans should be made to protect pets and livestock and persons should limit their outdoor exposure.

Winter Precipitation:

There will be a period of light rain and drizzle along and right behind the front. Thermal profiles cool during the day on Thursday to support a mix or change over to sleet/snow by mid morning. Feel that most of the precipitation will be ending prior to the arrival of the colder air and any light mix of sleet/snow will be very light with no accumulations expected. With that said we could see a brief period Thursday morning of sleet as far south as the US 59 corridor.

[Tireman4]

Just let ur faucets drip (do middle so both warm/cold drip)...we did during the 1989, and 1983 freeze, and we were fine...wrap up exposed pipes outside.

Yep, works every time. Learned that from my grandma who lived in Texas City and was raised in northern Louisiana.

[CaptinCrunch]

Interesting the record low for Houston this Friday is 19F made back in 1996. For Saturday it is 19F made back in 1976.

Last time DFW saw negitive readings was Dec 23, 1989 and it was -1 below, under clear skies and calm winds.

[txagwxman]

From jeff this morning:

Widespread Freeze expect tonight.

Coldest air in over 10 years heading for the area by Thursday.

Hard Freezes likely Friday-Sunday mornings.

Discussion:

Polar front moved across the region overnight with low clouds lingering this morning. Moisture trapped below the frontal inversion should keep mostly cloudy skies in place through the early afternoon hours. With clouds and cold air advection, will need to lower high temperatures into the upper 40’s. Upstream air mass is cold and large snow pack over the central US is allowing little modification of this air. Hence will also need to go colder tonight and this places our NE counties on the fence for a hard freeze (25 degrees or colder for 2 hours). Metro Houston should fall into the upper 20’s to lower 30’s and in the mid 30’s along the beaches. Would not expect any serious issues with this cold as it has already been colder back in early December.

Tonight will be a small taste of what is to come. Upper air pattern undergoes significant amplification this week with a bitter cold air mass over NW Canada being unleashed southward into the US. Massive 1055mb surface high enters the US over Montana Tuesday and plunges due south down the plains through the Gulf of Mexico and into mainland Mexico. Will go with the fastest model guidance on frontal timing as once this dense very cold air begins to move…little is going to stop it. Will show the arctic boundary blasting through the region Thursday before sunrise…and it will be downhill from that point on. Highs in the 40’s prior to the front will tumble into the upper 20’s by early evening under strong NW winds of 20-30mph. Wind chills will fall into the teens over most of the area. Skies will clear out Thursday PM, but winds should help the temperatures from getting out of control by Friday morning…although a hard freeze is likely along and N of US 59 by Friday morning. Latest guidance only shows highs breaking about 35 for a few hours on Friday and locations N of HWY 105 may remain below freezing all day. Massive arctic ridge builds overhead Friday night with clear skies and light winds…there appears to be nothing to stop the bottom from falling out on the temperatures. Lows in the upper teens looks likely N of I-10 with near 20 at IAH and freezing temperatures to the beaches. Will only recover into the upper 30’s for a few hours on Saturday before the temps. tank again Saturday night with the arctic high remaining in control. Hard freeze most locations again Sunday AM. Plenty of time to fine tune the lows for Friday-Sunday mornings.

Some locations (mainly N of HWY 105) will likely see 36-60 hours of sub-freezing temperatures from Thursday PM- Sun AM. Intensity and duration of this event has not been seen in SE TX since IAH fell to 19 in 1996…prior to that one must go back to the snow/cold air outbreak of December 1989 when IAH fell to its all time record low of 7. Freezing temperatures will be felt even across deep south Texas with damage likely to the citrus crops in both Texas and Florida.

Residents across the region should begin to prepare for this significant cold air outbreak. Exposed outside pipes should be wrapped as temperatures in the 10’s/low 20’s will cause some issues along with the long duration of the event. Temperatures of this magnitude will kill any un-protected tropical vegetation…and even protected vegetation may have some serious issues. Heavy irrigation of the ground soils prior to the event and then multiple layers of coverings may help mitigate some of the damage. Pets and livestock will also need protection. With wind chills falling to dangerously low levels into the low teens if not the single digits plans should be made to protect pets and livestock and persons should limit their outdoor exposure.

Winter Precipitation:

There will be a period of light rain and drizzle along and right behind the front. Thermal profiles cool during the day on Thursday to support a mix or change over to sleet/snow by mid morning. Feel that most of the precipitation will be ending prior to the arrival of the colder air and any light mix of sleet/snow will be very light with no accumulations expected. With that said we could see a brief period Thursday morning of sleet as far south as the US 59 corridor.

Dec 1990 it got to 16F at IAH.

[srainhoutx]

12Z NAM is running. Further W through hour 66 with the PNA Ridge as well as the Upper Low and a weak wave near Northern MX/TX border.

[wxman57]

With the help of my coworker, I made a couple of graphics off the raw 06Z GFS data (below) for IAH (Houston). I'll make the same graphics for the 12Z run when it's out. Looks cold but no frozen precip here. Yeah, as the rain shuts down just behind the front we might see a few sleet pellets. Big deal.

[Portastorm]

12Z NAM is running. Further W through hour 66 with the PNA Ridge as well as the Upper Low and a weak wave near Northern MX/TX border.

Still looks pretty dry but I do notice some hints of upper level energy being sheared into the state from west from 72 to 84 hours. That would be one-half of the snow/sleet surprise question ... the other is available moisture and I don't see it yet.

[srainhoutx]

12Z NAM is running. Further W through hour 66 with the PNA Ridge as well as the Upper Low and a weak wave near Northern MX/TX border.

Still looks pretty dry but I do notice some hints of upper level energy being sheared into the state from west from 72 to 84 hours. That would be one-half of the snow/sleet surprise question ... the other is available moisture and I don't see it yet.

Agreed. I know wxman57 is watching closely as well as our other METS. Also noticed the NAM is a bit slower as well with the progression of the Upper Low. The ensembles have been 'sniffing' the wave further W as well. We shall see.

[gofrogs]

also watch the 12th throgh the 13th very carefully, just sayin.

[iorange55]

Also shows more precip into Colorado seems to me like something could come from the west 24-48 hours after the front. I remember earlier this year a cold front was expected to go through, and we were supposed to be dry. But about a day or two before the models were showing a piece of energy around Colorado moving down south into New Mexico, and into west Texas.

[srainhoutx]

Here are some nuggets out of Brownsville...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
916 AM CST MON JAN 4 2010

.NEAR TERM /THROUGH 6 PM TODAY/...
CLOUDS ARE THICKENING OVER THE WESTERN PORTION OF THE VALLEY AND
SLOWLY MOVING EAST. WILL KEEP SLIGHT CHANCE FOR LIGHT RAIN AND
DRIZZLE IN THE FORECAST FOR TODAY AND KEEP HIGH TEMPERATURES IN THE
MID 50S. THE COLD REINFORCING AIR WILL PUSH SOUTH LATER TODAY
CLEARING MOST OF THE LIGHT RAIN AND SOME CLOUDS BY LATE THIS
AFTERNOON.

.SHORT TERM /6 PM TODAY THROUGH 6 PM TUESDAY/...
TEMPERATURES WILL RAPIDLY DECREASE TONIGHT UNDER MOSTLY CLEAR SKIES
AND SHOULD WARRANT A FREEZE WATCH FOR THE NORTHERN AND WESTERN
COUNTIES BY LATE TONIGHT. WILL REEVALUATE THE SITUATION LATER TODAY
FOR POSSIBLE FREEZE WARNINGS. TEMPERATURES SHOULD MODIFY ON TUESDAY
INTO THE 60S FOR HIGH TEMPERATURES. SOME SUN SHOULD BE SEEN ON
TUESDAY AS DRIER AIR MOVES INTO THE AREA.

.LONG TERM /6 PM TUESDAY - SUNDAY EVENING/...
AWAITING THE 12Z MODEL SUITE TO MAKE ANY/FURTHER REFINEMENTS TO
THE TIMING/INTENSITY OF THE `POLAR EXPRESS` STILL ON TRACK FOR
THURSDAY. WILL NOT MAKE ANY MODIFICATIONS AT THIS TIME...BUT WILL
MENTION THAT THE 06Z GFS AND 00Z ECMWF TRENDS ARE IN LINE WITH A
TAD MORE COOLING PARTICULARLY FRIDAY INTO SATURDAY.

THE OTHER ISSUE THAT MAY NEED ADDRESSING IS THE POSSIBILITY FOR
SOME LIGHT MIXED PRECIIPITATION FRIDAY IN THE LOWER VALLEY FROM
EXTREME EASTERN HIDALGO TO THE COAST. YESTERDAY`S TREND FOR HIGHER
MOISTURE...INITIALLY HELD AS A CLOUD/VIRGA LAYER AROUND 700
MB...IS NOT ENHANCED BY MID LEVEL OVERRUNNING SOUTHWESTERLY FLOW
AS WELL AS A POTENTIALLY VIGOROUS JET STREAK WHOSE RIGHT ENTRANCE
REGION WOULD SETTLE OVER THE DEEPEST MOISTURE. GFS MODEL SOUNDING
FOR KBRO SITTING RIGHT ON THE SLEET/FREEZING RAIN/RAIN LINE...AND
NOT TOO FAR FROM EVEN ALL FROZEN (SNOW) ESPECIALLY IF EVAPORATIVE
COOLING COMES INTO PLAY. WILL SCUTINIZE 12Z DATA VERY CLOSELY IN
DETERMINING IF A NEED FOR A WINTRY MIX ARISES.

NEEDLESS TO SAY...THE CURRENT DOWNWARD TREND IN DAYTIME HIGH
TEMPERATURES ON FRIDAY (30S FOR MOST) IS ON TRACK AND MAY NEED
ADDITIONAL DOWNWARD NUDGING AS THINGS PLAY OUT.

MANY MORE DETAILS WITH THIS AFTERNOON`S DISCUSSION...SHORTLY
BEFORE 2 PM.

[Portastorm]

12z GFS slows the front up a bit through 66 hrs ... hmm.

[cctxhurricanewatcher]

Here are some nuggets out of Brownsville...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
916 AM CST MON JAN 4 2010

.NEAR TERM /THROUGH 6 PM TODAY/...
CLOUDS ARE THICKENING OVER THE WESTERN PORTION OF THE VALLEY AND
SLOWLY MOVING EAST. WILL KEEP SLIGHT CHANCE FOR LIGHT RAIN AND
DRIZZLE IN THE FORECAST FOR TODAY AND KEEP HIGH TEMPERATURES IN THE
MID 50S. THE COLD REINFORCING AIR WILL PUSH SOUTH LATER TODAY
CLEARING MOST OF THE LIGHT RAIN AND SOME CLOUDS BY LATE THIS
AFTERNOON.

.SHORT TERM /6 PM TODAY THROUGH 6 PM TUESDAY/...
TEMPERATURES WILL RAPIDLY DECREASE TONIGHT UNDER MOSTLY CLEAR SKIES
AND SHOULD WARRANT A FREEZE WATCH FOR THE NORTHERN AND WESTERN
COUNTIES BY LATE TONIGHT. WILL REEVALUATE THE SITUATION LATER TODAY
FOR POSSIBLE FREEZE WARNINGS. TEMPERATURES SHOULD MODIFY ON TUESDAY
INTO THE 60S FOR HIGH TEMPERATURES. SOME SUN SHOULD BE SEEN ON
TUESDAY AS DRIER AIR MOVES INTO THE AREA.

.LONG TERM /6 PM TUESDAY - SUNDAY EVENING/...
AWAITING THE 12Z MODEL SUITE TO MAKE ANY/FURTHER REFINEMENTS TO
THE TIMING/INTENSITY OF THE `POLAR EXPRESS` STILL ON TRACK FOR
THURSDAY. WILL NOT MAKE ANY MODIFICATIONS AT THIS TIME...BUT WILL
MENTION THAT THE 06Z GFS AND 00Z ECMWF TRENDS ARE IN LINE WITH A
TAD MORE COOLING PARTICULARLY FRIDAY INTO SATURDAY.

THE OTHER ISSUE THAT MAY NEED ADDRESSING IS THE POSSIBILITY FOR
SOME LIGHT MIXED PRECIIPITATION FRIDAY IN THE LOWER VALLEY FROM
EXTREME EASTERN HIDALGO TO THE COAST. YESTERDAY`S TREND FOR HIGHER
MOISTURE...INITIALLY HELD AS A CLOUD/VIRGA LAYER AROUND 700
MB...IS NOT ENHANCED BY MID LEVEL OVERRUNNING SOUTHWESTERLY FLOW
AS WELL AS A POTENTIALLY VIGOROUS JET STREAK WHOSE RIGHT ENTRANCE
REGION WOULD SETTLE OVER THE DEEPEST MOISTURE. GFS MODEL SOUNDING
FOR KBRO SITTING RIGHT ON THE SLEET/FREEZING RAIN/RAIN LINE...AND
NOT TOO FAR FROM EVEN ALL FROZEN (SNOW) ESPECIALLY IF EVAPORATIVE
COOLING COMES INTO PLAY. WILL SCUTINIZE 12Z DATA VERY CLOSELY IN
DETERMINING IF A NEED FOR A WINTRY MIX ARISES.

NEEDLESS TO SAY...THE CURRENT DOWNWARD TREND IN DAYTIME HIGH
TEMPERATURES ON FRIDAY (30S FOR MOST) IS ON TRACK AND MAY NEED
ADDITIONAL DOWNWARD NUDGING AS THINGS PLAY OUT.

MANY MORE DETAILS WITH THIS AFTERNOON`S DISCUSSION...SHORTLY
BEFORE 2 PM.

I was about to post Brownsville's discussion... Wow if that would happen. What caught my eye was the downward trend in temps DURING THE DAY ON Friday from the upper 30's.