Texas Winter 2014-2015

[BigB0882]

Woke up this morning in Baton Rouge, 21 degrees according to the app on my phone. Anyone know what the low officially was?

[weatherdude1108]

Left house this morning just after 7am. It read 22.7 degrees, dewpoint 6.8 degrees. Barometer reading of 30.47. Very DRY, dense air mass.

[amawea]

It's bitter cold here in the northern Ozarks this morning. The only thing coming from that Ozark shadow should be cold air. My weather station showed 0.8 degrees at 6:20 a.m. I am just a few miles from the Mo. line.

[gboudx]

Morning update from jeff:

Potential for freezing rain tonight/Friday morning and Friday night/Saturday morning far north and west counties…this does not include Harris County or metro Houston.

Discussion:
About as complicated and uncertain of a forecast as one will have in SE TX over the next 72 hours with cold air and moisture to combine to produce bouts of precipitation over the region. Will start first with the ongoing freeze over the region. 600am temperatures ranged from 24 at College Station and Huntsville to 30 at IAH, 28 at Wharton, and 31 at Victoria. Core or surface arctic high is centered from NE TX into the OH valley with weak cold air advection still in progress…expect another degree or two of temperature fall this morning. Really not reaching that hard freeze criteria in the warning area...and it is doubtful that will happen at this point. CLL did have a 500am wind chill of 14 which is 1 degree off the wind chill advisory criteria for this region.

Very slow warm up today to near 40 with increasing mid and high level clouds associated with the approach of an upper air disturbance from the southwest….and hence begins the complicated forecast portion.

Tonight/Friday morning:
Moisture will increase late today as a brief period of southerly winds return late this afternoon ahead of another surge of cold arctic air currently entering the US near Montana. This secondary arctic front will cross the area late tonight and early Friday at the same time an upper level disturbance crosses the area. Temperatures will fall back below freezing tonight along and north of a line from Columbus to Livingston with above freezing temperature south of that line. Combination of frontal lift with the upper air disturbance should produce very light precipitation across the region late tonight and Friday morning. Where temperatures are below freezing this will fall as freezing drizzle and ice pellets. QPF values are only in the .01 to .10 range where the surface temperatures are below freezing (north of the Columbus to Livingston line). Think most of this will be freezing drizzle, but soundings showing varying depth of surface cold dome which could introduce a little more sleet (IP). Best estimates at the moment are for minor icing impacts on elevated surfaces early Friday morning where any precipitation reaches the ground.

Friday night/Saturday morning:
Main Baja storm system will begin to move toward the state late Friday and into Saturday. Models are in some agreement that light precipitation on Friday will move southward with a dry period for most of Friday night into Saturday morning when once again surface temperatures become critical. Surface freezing line Saturday morning digs southward west of Houston, but does not push much southward over the central or eastern parts of the region. Freezing line Saturday morning will run roughly from Edna to Columbus to College Station to Livingston. Precipitation will start to break out from SW to NE mid morning and spread across the region during the day. Forecast profiles show strong warm air advection above the shallow arctic dome suggesting the chances for sleet greatly decline in favor of freezing rain where surface temperatures are below freezing. Main question is does any precipitation fall when surface temperatures are below freezing…at this point it looks very marginal as the onset of QPF is midday into the afternoon on Saturday. Low level dry air mass once again has to be overcome and Baja storm system are notorious for being slower moving than guidance…or their rainfall is usually slower to arrive than expected. Too much uncertainty to both on surface temperatures and QPF to suggest any ice amounts for those western and northern counties Saturday morning. Could be a big mess across central TX into SW TX where freezing temperatures and greater QPF suggest much more ice potential.

Saturday night/Sunday morning:
Will likely see widespread rainfall during this period starting Saturday afternoon and continuing through Sunday. Temperatures should slowly warm through the period, but will still have to watch Sunday morning up north and out west for any sub freezing temperatures to once again introduce freezing rain. WPC freezing rain probabilities for SE TX are greatest Saturday night/Sunday morning and include a bigger chunk of the area. Still think this is overdone and too aggressive given the amount of warm advection expected above the surface…warm rain drops falling into cold air should help warm the low level air mass slowly. Only potential issue I see with that is that the heavier rainfall rates may/could result in more low level evaporative cooling…so it will be a battle Saturday evening/night between these two processes….will lean toward the warm rain drops overwhelming in evaporative effects.

Point to be made for all this is that this is a marginal winter weather event for the northern and western counties of SE TX for each overnight period tonight-Saturday night. The difference in surface temperatures of 1-2 degrees will determine all rain versus freezing rain and ice. Surface air temperatures are very marginal and QPF is not really lining up with the critical cold periods which inserts tremendous uncertainty into the forecast. Best estimation at this point is that any freezing rain/ice will remain northwest of Houston and Harris County through the entire period.

[ATCcane]

Here at Hudson Bend, I had a low of 21.6 at 7:17 this morning. As of 9:00am its a blazing 23.8 with a dew point of 6. The temp was on its way up but a broken layer of clouds is moving in and the rise has been slowed somewhat.

[Portastorm]

Why, this time, I do think the models are on crack ... the 12z NAM predicts temperatures for Austin tomorrow morning at 6 am of being 36. No way that happens. We're sitting 27 right now and that is in the core of downtown with immediately surrounding areas in the mid 20s. We may only hit 36-38 today as a max temp and even with increasing cloud cover we'll most certainly fall below 36 by 6 am tomorrow.

The 0z/6z GFS runs show us at 36-37 degrees. How is it going to warm up if we have another frontal boundary moving through the area (or have moved through the area) by that time?

No way that happens.

[BrokenGlassRepublicn]

When do the real time models come into play to see exactly which way the moisture is going to head? Aren't we getting close to that time?

Here is a which goes out 15 hours. Shows rain developing towards the end of the loop --> http://mag.ncep.noaa.gov/model-guidance-model-parameter.php?group=Model%20Guidance&model=hrrr&area=cent-us&cycle=20141104%2016%20UTC&param=sim_radar&fourpan=no&imageSize=M&ps=area

[wxman57]

Under warm advection, the Euro has Austin's temperature reaching 38 by 6pm, 38 at midnight and rising to 39 by 6am. GFS has raw 2m temps of 36 for noon in Austin, a high of 42, then dropping to 39 at 6pm and holding at 37 all night with the clouds & warm advection countering overnight cooling.

It may well be that the temperature doesn't fall this evening/overnight. What will it hit this afternoon, though?

[Ntxw]

At the same time the next big HP is sending another surge of cold air, how quickly does that start to counter WAA in about 24 hours?

[texas1836]

Hit a low of 13' at the DWC in McKinney, now sitting at 22'.

[srainhoutx]

DFW hit 16F this morning at 7:13AM

[Snowman67]

Under warm advection, the Euro has Austin's temperature reaching 38 by 6pm, 38 at midnight and rising to 39 by 6am. GFS has raw 2m temps of 36 for noon in Austin, a high of 42, then dropping to 39 at 6pm and holding at 37 all night with the clouds & warm advection countering overnight cooling.

It may well be that the temperature doesn't fall this evening/overnight. What will it hit this afternoon, though?

Wxman57 - Do you concur with the models regarding temps tonight?

[Ntxw]

DFW hit 16F this morning at 7:13AM

Which matches the March 3rd cold blast earlier this year (the infamous blast that brought us bipolar wxman57) that also was the last time DFW got down to 16F. Yet the 06z GFS raw temps still suggested low 20s lol

[Portastorm]

Under warm advection, the Euro has Austin's temperature reaching 38 by 6pm, 38 at midnight and rising to 39 by 6am. GFS has raw 2m temps of 36 for noon in Austin, a high of 42, then dropping to 39 at 6pm and holding at 37 all night with the clouds & warm advection countering overnight cooling.

It may well be that the temperature doesn't fall this evening/overnight. What will it hit this afternoon, though?

Predicted high is 40 today. I don't think it gets above 37-38. GFS shows us at 36 in 2 1/2 hours and it's only 25-26 at this moment ... so it's going to warm 10 degrees in 2 1/2 hours?! Bwahahahahaaa. Nope, sorry GFS. You're wrong.

The models may be selling warm air advection but I'm not buying. Sorry. It won't be that strong.

[wxman57]

Under warm advection, the Euro has Austin's temperature reaching 38 by 6pm, 38 at midnight and rising to 39 by 6am. GFS has raw 2m temps of 36 for noon in Austin, a high of 42, then dropping to 39 at 6pm and holding at 37 all night with the clouds & warm advection countering overnight cooling.

It may well be that the temperature doesn't fall this evening/overnight. What will it hit this afternoon, though?

Predicted high is 40 today. I don't think it gets above 37-38. GFS shows us at 36 in 2 1/2 hours and it's only 25-26 at this moment ... so it's going to warm 10 degrees in 2 1/2 hours?! Bwahahahahaaa. Nope, sorry GFS. You're wrong.

The models may be selling warm air advection but I'm not buying. Sorry. It won't be that strong.

The models are probably too "warm" for Austin today/tonight, but I could see the temperature reaching 35-36 this afternoon and not dropping below freezing tonight.

[Portastorm]

Fair enough ... but here is how crazy I am about this one ... I'm so confident I'll be correct (i.e. the temperature in Austin tomorrow morning at 6 am will be BELOW 36 degrees) that if I am wrong, I will use this image as my avatar for two weeks!

[Longhornmaniac8]

SHOTS FIRED!!!! SHOTS FIRED!!!

[hriverajr]

I fear for you Porta hahaha Wind already turned to the south here in Del Rio, the sun is poking out and its 35 degrees out. Think of us as an early warning system.

[Ntxw]

GFS MOS has Austin to around 33F will be close if it's correct. From last night's output anyway.

MOS guidance has been better than raw OP output for just about everyone with this air mass.

[dhweather]

It is coming .......