TX Winter WX Thread #7 - An Icy and Rough Weekend Ahead

[HarlequinBoy]

Well even up here near Memphis the front (or maybe just the winds) keep moving through and then moving back. The temperature has dropped from the mid 60s to the mid 50s several times just to go back again once the winds switch back and come from the SE.

[Portastorm]

NWS Austin/San Antonio AFD mentions better shot at sleet and/or snow. I don't know ... we're in the upper 30s to low 40s right now. I guess I'll believe it when I see it falling from the sky.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
432 PM CST SUN JAN 14 2007

.DISCUSSION...
AN SPS TO BE SENT OUT SHORTLY TO ADDRESS THE ICING CONCERNS OVER
THE NEXT 2 DAYS. CONTINUOUS RAIN IN THE SHALLOW COLD AIR LAYER HAS
HELD BACK THE FREEZING CONDITIONS AND ACTUALLY WARMED AFTERNOON
MAX TEMPS INTO THE 50S NEAR AND WEST OF SAT. THE NEXT THREAT FOR
COOLING ENHANCEMENTS IS FOR A SHORTWAVE MOVING ACROSS NRN MEXICO
THAT WILL LIKELY INCREASE THE CHANCE OF SLEET OVER WESTERN AND
NORTHERN PORTIONS OF SOUTH CENTRAL TEXAS. IF ENOUGH FROZEN PRECIP
FALLS, THE FREEZING LINE COULD ACCELERATE SOUTH INTO THE METRO
CITIES BY MORNING. FOR NOW WILL LEAVE SAT OUT OF ANY ADVISORIES,
BUT THIS MAY NEED REEVALUATION THIS EVENING.

BY DAYTIME MONDAY...NAM MODEL SOUNDINGS SHOW A DEEPENING INVERSION
LAYER DIPPING BELOW FREEZING AND INCREASING COLD AIR
ALOFT...SIGNALLING AN INCREASED CHANCE OF SLEET AND SNOW FOR
MONDAY NIGHT INTO TUESDAY. THUS THE ICING POTENTIAL FOR NORTHERN
COUNTIES MAY BE GREATEST MONDAY EVENING. A COMPOSITE OF MODEL
PRECIP FORECASTS SUGGESTS GRADUALLY DECREASING CHANCES TUESDAY,
WITH DRIER AIR EXPECTED TO STABILIZE THE AREA WEDNESDAY.

IN THE LONG RANGE...ONCE AGAIN THE RAPID FIRE OF DISTURBANCES IN
A MOIST AN ACTIVE SUBTROPICAL JET ALOFT WILL MAKE THE CHANCE OF
RAIN DIFFICULT TO ASSESS THIS FAR OUT. WILL CONTINUE TO LEAVE OUT
DETAILS AND BROADLY FOLLOW GFS FOR SKY AND TEMPS WHILE
UNDERCUTTING THE AGRESSIVE POPS. TRENDS ARE FOR MILDER WEATHER
LATE IN THE WORK WEEK, BUT GOOD MERIDIONAL FLOW COULD BRING FORTH
ANOTHER RESURGENCE OF ARCTIC AIR BY SATURDAY.

[Tamora]

My winds just switched back around to the north (lightly) here in western Spring. Looks like the front has once again drifted past me to my SE.

Sounds like the front is waffling around like what the freezing line is doing up here. We've been between 32-34 all day.

We are finally at 31.4 (4:48pm). We haven't dropped below this. We got out to go to Sonic (cabin fever set inLOL) and the trees are covered in ice, but that is it. I think we have had over 3 inches of rain, maybe even close to 3.5. I emptied the gauge not wanting it to break due to freezing.

[Extremeweatherguy]

Based on this: http://www.wunderground.com/stationmaps ... &wmo=99999 I would say that the front is probably now along a Livingston to Spring to Sugar Land line (or close to that). It will probably reach downtown again within the next few hours and then be accelerated off the coast as the secondary cold surge arrives.

[Extremeweatherguy]

Personal weather station near west Katy is showing a current temp. of 54-degrees out there. Also a station up in clear creek forest is showing 53-degrees. Also, up near Montgomery there is a personal station report of 52-degrees. All of these areas were in the upper 50s and 60s less than an hour ago.

[cheezyWXguy]

where is the secondary arctic surge right now? weve got a massive sheet of frozen precipitation moving straight this way!

[Tireman4]

Look at all that ice and snow north of Houston. Goodness.

http://www.intellicast.com/IcastPage/Lo ... odnav=none

[Tireman4]

I think, and please someone correct me if I am wrong, that is in the panhandle of Texas.

[wall_cloud]

the seconday surge of cold air will not necessarily be COLDER than that which already came through. However, it will reinforce the cold air already in place...prolonging the cold snap and driving the cold dome even farther south. It will be aided by the strong northerly flow on the backside of the surface low. This will push through the area as the upper-low ejects northeast. You probably can't find a traditional front as mentioned earlier...but the stronger winds a good clue as to where the surge is located.

[Ptarmigan]

It's really warm and humid right now.

[cheezyWXguy]

the seconday surge of cold air will not necessarily be COLDER than that which already came through. However, it will reinforce the cold air already in place...prolonging the cold snap and driving the cold dome even farther south. It will be aided by the strong northerly flow on the backside of the surface low. This will push through the area as the upper-low ejects northeast. You probably can't find a traditional front as mentioned earlier...but the stronger winds a good clue as to where the surge is located.

Well im still somewhere between 30 and 32 so it doesnt matter too much that it wont make it any colder...however, will it thicken the air at all? The air is still so shallow that it is only raining at the surface, even tho its below freezinf

[Extremeweatherguy]

yeah, the second "surge" will have far greater affects in south and SE Texas than up north. down here it will drive temps. to near freezing by Monday night with highs in the lower 30s on Tuesday...but up in Dallas it will only help knock a few degrees off the lows and a degree or two off your highs for tomorrow (which will still be near or below freezing). Either way though it will mean a much better threat of winter weather for us all when it arrives (due to even colder air), and based on the winds it seems this "surge" is currently working down the TX panhandle and down into Oklahoma as well (OKC is currently gusting up near 30mph with sustained winds over 20mph out of the north).

Also, Cheezywx...yes, it could thicken the cold airmass some (or at least I think it could). This is why many areas gradually change the freezing rain over to sleet (and even snow) in parts of the state by Tuesday and Wednesday. Up in Dallas it may end as some sleet for you guys.

[Tamora]

where is the secondary arctic surge right now? weve got a massive sheet of frozen precipitation moving straight this way!

I just saw that... I wonder when they are expecting that to move in to the area. We are still at 31.4

[double D]

the seconday surge of cold air will not necessarily be COLDER than that which already came through. However, it will reinforce the cold air already in place...prolonging the cold snap and driving the cold dome even farther south. It will be aided by the strong northerly flow on the backside of the surface low. This will push through the area as the upper-low ejects northeast. You probably can't find a traditional front as mentioned earlier...but the stronger winds a good clue as to where the surge is located.

Thanks for that explanation wall_cloud as I did not see anything that "frigid" up north and wondered how it was going to get that cold in central and southeast Texas.

[TrekkerCC]

where is the secondary arctic surge right now? weve got a massive sheet of frozen precipitation moving straight this way!

I just saw that... I wonder when they are expecting that to move in to the area. We are still at 31.4

It's been hovering at 32/33 all day. I do see some sleet/mix out to the west. If we drop below freezing before the precipitation (29 to 30), the icing could be more significant than it is now.

[gboudx]

where is the secondary arctic surge right now? weve got a massive sheet of frozen precipitation moving straight this way!

I just saw that... I wonder when they are expecting that to move in to the area. We are still at 31.4

Our dewpoint has dropped to about 30, with an air temp of 32.6. So the temp has room to drop before that precip makes it this way.

[southerngale]

NWS Austin/San Antonio AFD mentions better shot at sleet and/or snow. I don't know ... we're in the upper 30s to low 40s right now. I guess I'll believe it when I see it falling from the sky.

I'm with you. I just don't think we're going to have the problems with ice, etc. I know the models show it, but they also showed this first cold front reaching us and I'm quite sure they showed the temperatures as colder, where it did reach. I think we'll end up talking about how the precip arrived and left before the colder temps set in or the precip is there, but it's just not quite as cold as we thought....something along those lines. I know..."we didn't expect this and we didn't expect that" - well, who knows what may happen that we don't expect next?


Of course nobody should listen to me as I am certainly not qualified to "forecast" anything. I'll eat crow in a few days if I'm wrong.

[wxman57]

Look at all that ice and snow north of Houston. Goodness.

http://www.intellicast.com/IcastPage/Lo ... odnav=none

I believe that the radar image isn't calibrated properly. That should be all rain , freezing rain, and a bit of sleet. That's not snow in Texas.

[Portastorm]

I totally agree SG and have been fielding a few e-mails today from friends saying "hey weatherman, where's this big ice storm?"

But you know, my local NWS has been really good the last 24 hrs. Today's forecast was right on the money and I thought they would be too warm. Maybe I should have more faith but Lucy keeps pulling that dang football from me!!

[wxman57]

Everything is setting up pretty much as forecast, with a major ice storm possible for central and southeast Texas. The emphasis should be on CENTRAL Texas rather than the Houston to Beaumont area, though. The air won't be quite cold enough across Houston for any freezing rain until tomorrow night through Tuesday night. What you'll see tomorrow is the secondary surge of Arctic air reaching Houston in the morning after sunrise and the front moving off the entire TX coast. Temps will slowly fall, down to the upper 30s by mid afternoon, mid 30s by sunset, and possibly below freezing by late evening. That's when the threat of icing in the Houston area begins.

It may be difficult to get much ice south and east of downtown, as temperatures there may hover in the 33-35 degree range Monday night through Tuesday night. Best chances for significant accumulations will be north and northwest of a line from Victoria to Bush Intercontinental airport. Areas south of that line may see some icing on elevated surfaces, but it may not be cold enough for much ice on the ground, particularly the streets. Bridges could get icy, though, even on the south side of Houston. Doesn't take much ice on a bridge to cause big problems.

As far as damage, I think for the greater Houston area, the main threat will be for slick roadways and hazardous travel. North and west of central Houston is where the ice may be heavy enough to cause problems with trees and power lines. San Antonio, Austin, Waco, College Station -- that area -- will likely see the heaviest accumulations. For downtown Houston south through Clear Lake, Friendswood, Pearland, maybe a trace to 1/4" of ice, not necessarily on roadways except for bridges.