Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 5

[Srain]

Morning Update from Meteorologist  Jeff L (Harris County Flood Control District):

 

Powerful arctic cold front entering SE TX this morning.

 

Increasing potential for significant ice storm across N and NE TX Friday-Sunday with SE TX on the southern edge of the event

 

Arctic boundary has entered the area this morning with College Station now at 53 degrees and Houston at 72. Upstream observations are 37 at Dallas, 15 at Amarillo, and -10 at Denver. Front is making good southward progress and will be through the metro area before noon and offshore by mid afternoon. Temperatures will fall 20-25 degrees with the frontal passage and continue to cool quickly into the 40’s by afternoon possibly upper 30’s NW. Do not expect much rainfall with the front, but chances for rain will increase overnight into Friday.

 

Main portion of this forecast will be on the potential for freezing rain and freezing drizzle across the area Friday-Sunday and low temperatures next week.

 
1.       Temperatures: Models continue to show slightly colder conditions as is usually the case with such shallow arctic air masses. This places near/sub-freezing surface temperatures across our NW counties as early as 300-400am Friday morning (College Station to Huntsville). Expect very little is any warming on Friday as cold air advection process continues to bring frigid air southward off the central plains and across extensive ice formation over N TX. May see temperatures hold steady in the 32-35 range all day Friday over our NW and N counties and in the upper 30’s to lower 40’s across the rest of the area. By Friday evening the freezing line will progress southward likely reaching a Hempstead to Conroe line overnight into Saturday morning. Highs on Saturday may stay very near freezing from Hempstead to Conroe northward. Saturday night into Sunday the freezing line moves southward again possibly reaching a line from Columbus to Tomball to The Woodlands. Many areas will fall into the 30’s tonight and not rise above 40 until maybe Sunday. Good news is that cloud cover will keep overnight lows in the upper 20’s NW to mid-upper 30’s coast.

 

2.       Precipitation and Type: Forecast soundings show a classic overrunning situation with shallow cold air ranging anywhere from 900ft to nearly 2000ft deep across the region with a significant warm layer above that due to south winds riding up and over the surface cold dome. This supports a freezing rain profile with liquid rain falling out of the warm layer aloft and then freezing on contact forming a layer of ice. This will only work if the surface temperature is at or below freezing….otherwise it is all rain. The profiles do not support sleet or snow with such warm air aloft. In fact one item to keep in mind is that the rain drop will actually likely be slightly warmer than the surface air temperature due to its descent through such a warm layer aloft so even if the surface temperature is 32 it may be hard to get ice to form.  Disturbances moving NE across the area will determine the best time periods for rainfall across the region…but expect amounts to be generally light.

 

Think there is at least a decent chance of freezing rain/drizzle over our NW counties as early as Friday and continuing into Sunday…this is mainly NW of a line from Brenham to Huntsville. Each night with the southward advance of the freezing line, the potential shifts SE for both Saturday and Sunday mornings and possibly includes the N and NW portions of Harris county, much of Montgomery County, Waller County, and portions of Austin County.

 

3.       Ice Accumulations: Ice will only form if the air temperature is 32 or lower at the surface. Think the best rain chances will be from midnight tonight until about noon on Friday when most of the area should be above freezing. As temperatures fall to the freezing point, rainfall should be on the decrease in intensity mainly just light rain and drizzle. Accumulations of ice from Friday evening –Sunday morning of .01 to .05 of an inch will be possible NW of a line from Brenham to Conroe to Livingston and this will mainly be on elevated surfaces such as trees and power lines. Could see a few icy bridges in this area also especially by Sunday morning as the pavement cools over time. Further southward the threat is much more conditional as the rain must fall in the short window when the temperature may be near freezing which reduces accumulation. Any light ice accumulation north of a line from Columbus to Tomball to The Woodlands would be in the trace to .05 of an inch and mainly on Saturday morning for a few hours and again on Sunday morning.

 

4.       Impacts: Do not see much if any issues with trees and power lines across the area…although those NW continues will have to be watched closely as accumulations of up to .10 of an inch could begin to cause some widely scattered outages and downed tree limbs. Ground temperatures are warm so it will take time for the air mass to cool the pavement to the freezing point allowing ice formation on elevated surfaces (bridges and overpasses). Do not think there will be any problems on Friday. By Saturday morning a few bridges could have some ice in the College Station to Huntsville area and then by Sunday morning north of a Brenham to Conroe line. Again we are talking very light amounts, but freezing drizzle is one of the worst types of winter weather as it produces a very thin layer of ice on the pavement that almost appears dry. Right now think Harris County will not have ice formation on bridges and overpasses, but it could be close on Sunday morning N and W.

 

Uncertainty: As with all winter weather events in this area, there is always a degree of uncertainty as the difference of 1 degree can make the difference between rain and ice. Determining the exact freezing line location at any given time is fairly difficult, yet that determines where the rain/ice line will be. This is a moving target at this point and even during the event.

 

Winter Storm Warning/Ice Storm Warning area (N and NE TX):

 

Across N into NE TX conditions will be much worse with a significant ice storm expected from late tonight-Sunday. Surface temperatures in the mid to upper 20’s with liquid rain falling and freezing on contact is about as bad as an ice setup you can get. Rainfall amounts in this region may reach 1.0-1.25 inches with ice accumulation of .25 to .50 of an inch resulting in widespread heavy ice formation on trees and power lines. Ice accumulation will be more than enough to down large tree limbs and power lines resulting in potential widespread and prolonged power outages. Travel even on surface streets will be difficult if not impossible. This will be a prolonged event with temperatures falling below freezing tonight and likely not rising above freezing until sometime toward the middle of next week.

 

Next Week Cold:

 

Secondary arctic surge will arrive into the region Monday. Models continue to advertise extremely cold air moving southward with the 32F line pushing toward the coast and the 0F line reaching toward the Red River. With skies likely clearing, the setup will be for bitter cold conditions by Tuesday morning. Could see hard freeze criteria (25 or lower for 3 hours) north of I-10 by Tuesday morning. This is still a ways out and there could be some changes to the amount of cold that moves southward, but with a good snow cover over the central plains and N TX covered in ice, this air mass will not moderate much. Something to keep an eye on as this would require pipes to be protected across our region.

[bubba hotep]

Winter Storm Warning/Ice Storm Warning area (N and NE TX):

 

Across N into NE TX conditions will be much worse with a significant ice storm expected from late tonight-Sunday. Surface temperatures in the mid to upper 20’s with liquid rain falling and freezing on contact is about as bad as an ice setup you can get. Rainfall amounts in this region may reach 1.0-1.25 inches with ice accumulation of .25 to .50 of an inch resulting in widespread heavy ice formation on trees and power lines. Ice accumulation will be more than enough to down large tree limbs and power lines resulting in potential widespread and prolonged power outages. Travel even on surface streets will be difficult if not impossible. This will be a prolonged event with temperatures falling below freezing tonight and likely not rising above freezing until sometime toward the middle of next week.

 

Really hope this doesn't pan out.  We were without electricity for almost a month after Andrew and not looking forward to a prolonged power outage again.  I'll play it by ear today but may have to hit up Lowe's on the way home and grab a generator.

 

[aggiegeog]

Temps seem to be dropping a bit faster than expected with the northwestern metroplex below freezing and temps in the mid to upper 30s around here.

[Quixotic1]

34 with 20 dp.  Precip will have to be pretty heavy to moisten that up a bit. 

[msp]

CLL down to 43/36 already, which certainly seems to be ahead of schedule for cooling

[Srain]

Numerous reports of heavy icing in the Lubbock area on surface roads. LUB reports the models have under estimated to moisture and cold surface temps. Winter Storm Warning coming shortly.

[Ed Lizard]

New GFS crushes between the Metroplex and about Paris...

[texankitcat]

^{What do you mean by it "crushes"?} 

[1900hurricane]

^{What do you mean by it "crushes"?} 

Generous QPF in what is likely to be a sub-freezing airmass.

 

[bubba hotep]

Not looking good for the northern burbs....

 

 

 

Maybe we switch over to sleet and don't get as much icing.

[bubba hotep]

Down to 32, IMBY, freezing line is slowly pushing through

[DoctorMu]

32 DP line nearing Bryan.

[aggiegeog]

Temps in the low to mid 30s here with scattered areas of light precip. Round 1 is pushing through the Metroplex with temps around freezing. These temps were not expected until tomorrow morning so it appears that things are continuing to be colder than forecasted leading to just about all precip north of I-20 to be wintery. Seeing reports of snow into the Wichita Falls area also. 

[canderson]

My parents are scheduled to travel from NE Texas to Palestine tomorrow evening (Palestine is somewhat near Tyler, Smith County) for a football game at 7 p.m. Any ideas from anyone if they'll be clear at that point for safe travels?

[Quixotic1]

sleet and freezing rain in frisco

[NTXYankee]

Sleet and freezing rain in Lewisville too. Cars are icing up in parking lot at work

[aggiegeog]

My parents are scheduled to travel from NE Texas to Palestine tomorrow evening (Palestine is somewhat near Tyler, Smith County) for a football game at 7 p.m. Any ideas from anyone if they'll be clear at that point for safe travels?

 

I expect it to be pretty icy for that drive, nearer Palestine it may be a bit better. My wife works there and has to commute from north of I-20 and she is not planning on going in tomorrow.

[canderson]

I expect it to be pretty icy for that drive, nearer Palestine it may be a bit better. My wife works there and has to commute from north of I-20 and she is not planning on going in tomorrow.

Ah, Lindale! I was an editor at the Tyler Morning Telegraph for a few years ... grew up outside Longview. Wave hi to the wonderful pine trees for me but more importantly you guys be safe the next few days. Thank you for the answer, I'll warn them. They're going to see the playoff game there - wonder if they end up recrudescing it anyway.

[wxmx]

lower 30s here as well

 

 

 

 

 

 

celsius 

[Ed Lizard]

lower 30s here as well

 

 

 

 

 

 

celsius 

Couple of hours ago Laredo was 83ºF and an hour up I-35 Cotulla was 59ºF.  Houston dropped 10ºF in an hour when the front passed.

 

And from oil field country of SW Wichita County...

[bubba hotep]

Down to 30, IMBY, and looks like the 12z GFS spits out 1.50+ inches for us tonight... could get ugly.  The 00z soundings will be interesting, maybe the warm nose won’t be as aggressive as modeled and we will get more sleet than expected.

 

ETA: Wife is reporting freezing rain and sleet at the house up in Collin County

[DFWWeather]

It is officially 31°F at DFW Airport. Freeze line about 3 hours ahead of schedule.

[aggiegeog]

Temps have dropped below freezing in many locales around here with some light rain reported. Main band is still 75 miles west.

[SnowGoose69]

What is the deal with DFW reporting rain with a temp of 31

[bubba hotep]

Just old fashioned rain here in downtown at the moment

[msp]

down to 38/32 here in CLL now with both temp. and td falling; winds gusting strongly out of the north

 

maybe a shot at frz rn tonight?

[aggiegeog]

The Ice Storm Warning has been updated to start at 6pm for NE TX and SE OK. Scattered showers increasing in coverage ahead of main band of round 1 with temps north of I-20 below freezing and slowly dropping still.

[Ed Lizard]

What is the deal with DFW reporting rain with a temp of 31

 

Might be related to the FWD disco mention of rain drops warmer than freezing falling onto ground still in the 40s, even if the 2 meter temps are below freezing, and staying liquid.  It should be freezing on objects not in direct contact w/ the ground, and the latest ob is freezing rain now.

 

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS

DFW AIRPORT    FRZ RAIN  31  27  85 N14       30.11F FOG     WCI  21

DALLAS LOVE    FRZ RAIN  30  27  86 N12       30.13R FOG     WCI  21

 

EDIT to ADD:

 

 

Obviously, waiting anxiously for actual FWD 0Z soundings, but the warm nose is obvious.

 

[1900hurricane]

I'm quite intrigued to see what the 00Z FWD sounding reveals, especially compared to the RAP prog (below).

 

[Quixotic1]

yeah if this keeps up we are going to have problems in collin.  streets starting to glaze over.