February: Tracking Rain/Wintry Mix & Arctic Front

[jasons2k]

The leading edge of a strong front that will give the Eastern half of Texas a glancing shot of cold air is making progress SW from Arkansas and Northern Louisiana. Temperatures may approach the freezing mark again tomorrow morning mainly N of I-10 and East of 290. This shot of cold air will threaten Florida with freezing temperatures very far S into South Florida just NW of Ft Lauderdale.

And the NWS Ruskin has posted a freeze watch for tomorrow night in the Tampa-St.Pete-Sarasota corridor with predicted lows of 33-35. Kudos to them.

That's how it's done, folks.

[srainhoutx]

Temperatures this morning have remained above freezing with the colder locations holding in the mid to upper 30's. Clouds begin to increase this afternoon into tomorrow with a warming trend as a return flow off the Gulf becomes established. Rain chances should increase on Friday with a storm system developing off to our West near California/Nevada and increasing onshore flow ahead of the next strong front. Isolated storms may be possible Friday night into Saturday mainly off to our NE as the strong Arctic front approaches early Sunday.

Temperatures should fall quickly on Sunday as the front clears the Coast and upglide begins with the upper trough still back to our West. There is growing concern that as cold air continues to push S across Texas and over running moisture continues, a wintry mix of precipitation develops Sunday night into Monday mainly across Central Texas up into N Central and NE Texas with some potential of freezing rain and sleet as far South as College Station to Huntsville and Livingston. The GFS suggests areas N of HWY 105 could be close to the wintry mix and the European model is rather aggressive generating precipitation chances as well. The temperature profiles do raise an eyebrow with the GFS suggesting temperatures in the mid to upper 30's during the day on Monday very close to IAH. This piece of upper level energy looks to pass by Monday afternoon with a drying trend Monday night. The fly in the ointment continues to be a pesky cut off upper low to our West that the computer models keep stalled until around Wednesday before slowly dropping ESE into Southern Arizona and New Mexico by Thursday. Another shot of very cold air is expected late next week as the upper trough approaches. It is way to soon to know what our sensible weather will be next Thursday into Saturday, but the guidance is suggesting colder air at the surface will be established with over running moisture advancing E on Friday into early Saturday. This is a complex and complicated forecast, so expect day to day changes as the guidance resolves the complex upper pattern and the various shortwave disturbances that could cross our Region throughout next week. Is it Spring yet?!

[srainhoutx]

The 12Z GFS trended a bit colder (2 to 4 degrees) and is 'wetter' for Sunday night into Monday. If the GFS solution as well as the ECMWF come in somewhat similar, then we may need to pay a bit closer attention heading into the weekend for the potential of a wintry mess across a lot of our Region.

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[jasons2k]

Definitely worth watching as the models trend colder. I'm just glad the brunt of these cold shots is to the east. Lots of record lows will be broken tomorrow morning. I'm keeping a close eye on the trends in Florida for my friends and family over there. There are widespread freeze warnings in place now (imagine that!)

I am SO ready for spring and warmer weather. There is nothing fun about bundling-up and freezing your rear off while the car warms-up!!

[wxman57]

Here are a couple of meteograms for Houston (IAH). I wouldn't count on anything more than cold rain Monday, probably with some sleet mixed in. Similar to the last event. If we can make it through next week the long-range GFS is indicating some nice March warmth.

[Heat Miser]

wxman, always the voice of reason. Also the voice of weather I'm looking forward to "warmth"......

[Andrew]

Next weeks weather event could pose a little bit of interest for those in the northern part of SE Texas and farther north into central and northern Texas. The key here is how cold will the air be and how sheared will the once retrograded shortwave be. The GFS is the colder of the global models and does indicate a possibility of freezing rain up towards Conroe and College Station, but the thickness of this cold air is very shallow. We are talking about only 50-100mb up in the atmosphere with a very large warm nose extending from 950mb up to 650mb. For that reason alone, freezing rain looks like the only possible wintry precip for this part of the state. The other issue is the shortwave which will become extremly elongated and sheared as it enters the state. Many points of subsidence are foretasted on the lee side of the shortwave which could really hurt precipitation chances. The GFS only shows saturation up to 775mb with a pwat of 1inch before temps get cold enough at the surface. Overall I suspect with warm ground temperatures and such a shallow layer of cold air that cold rain will be the result with this next system.

[srainhoutx]

Afternoon briefing from Jeff:

Hope everyone enjoyed today…an extended period of cloudy cold weather will onset by Sunday and last much of next week.

Surface high moving eastward and a surface trough developing over west TX has allowed southerly winds to return to the region. Afternoon temperatures range from the upper 60’s around Matagorda Bay to the mid 50’s near the TX/LA state line. Warm air advection will increase tonight with a thick low level deck moving inland off the western Gulf of Mexico. Just enough lift is noted in the high resolution guidance to suggest a few passing showers or drizzle late tonight into much of Friday. Temperatures will warm into the 70’s on Friday with warm air advection even with extensive cloud cover.

Decent looking short wave will move across the area on Saturday with enough lift to likely generate a few showers and thunderstorms. Highs on Saturday will reach well into the 70’s…and this will be the warmest day by far of the next several. This system will more importantly usher in another strong arctic cold front on Sunday. Front will progress across the area during the day with temperatures falling from the 60’s and 70’s in the morning into the 40’s during the afternoon hours. Guidance is likely not handling this very cold shallow air mass very well and it is possible that temperatures could fall into the 30’s by Sunday evening. Troughing hangs back over the SW US keeping warm air riding up and over the surface cold dome into early next week for a soggy and cold forecast. Do not expect temperatures to make it out of the 40’s on Monday and would not be surprised to see some areas remain in the 30’s all day.

Critical time period is narrowing in on Monday night into Tuesday morning as near/sub freezing temperature line may push southward into the region especially if the models are under-forecasting the intensity of this cold air mass. Moisture and lift will likely be maintained into Monday night/Tuesday morning suggesting a potential for P-type concerns. Main concern area at the moment will be along and north of a line from College Station to Livingston. Forecast model profiles show a strong warm nose (pocket of above freezing air) a few thousand feet above the surface suggesting main P-type would be rain or possibly freezing rain where surface temperatures fall to freezing. GFS is much colder than the ECMWF model which keeps most of the area above freezing. For now will keep all precipitation liquid across the entire area, but watch temperature trends very closely over the weekend. If the ECMWF begins to trend toward the colder GFS solution then a very challenging forecast would be possible for early next week across SE TX.

[Paul Robison]

Would we be looking at serious freezing rain event (iced-up roads, falling trees, black ice, falling power lines, et. al.), or a just a minor (nuisance) one?

[Ptarmigan]

A freeze in late February to early March is not unusual. There are big March freezes in 1923, 1932, 1943, 1980, 1989, and 2002.

[wxman57]

Would we be looking at serious freezing rain event (iced-up roads, falling trees, black ice, falling power lines, et. al.), or a just a minor (nuisance) one?

I can't tell where you're located so I'll assume you're in Houston. For the greater Houston area I'd expect cold rain with temps above freezing at the surface. Perhaps up in Conroe to Huntsville and areas north the surface temps might dip below freezing enough for some freezing rain to accumulated on bridges and overpasses. No heavy accumulations down here.

[srainhoutx]

HGX is suggesting IAH may flirt with freezing temperatures Monday afternoon/evening and that the overnight models trended a bit colder. That said it is going to be a close call and with warm ground temperatures, not many issues are expected across Metro Houston but they are going to monitor the trends very closely today into the weekend. The 09Z SPC SREF Ensemble longer range does suggest there may be some p-type issues, but we will need to watch the trends into tomorrow to see if there is any real shot of a wintry mix across Metro Houston. Remember these events are always a forecast challenge and depending on sounding data and temperature profiles beyond 12 to 24 hours out is like rolling the dice at a craps table in Las Vegas.

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[srainhoutx]

The 00Z European certainly is anything but warm and Spring like later next week across our Region. I am sooo ready for Spring like weather...sigh

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[BlueJay]

I'm ready for Spring, too, but I think that we have had a really mild winter so far. I think I have had to major cover the Philodendron only twice since November 2014. That's great because I was under the impression that winter 2014-2015 was expected to be record breaking cold. I don't think it has been, so far.

[Heat Miser]

I agree BlueJay. I believe it may have been below norms for highs and lows, but nothing on the extreme side as far as hard freezes go.

[tireman4]

This is will be interesting times for the Houston area (and the state of Texas) weatherwise for next week. Please stay tuned to your NWS, here and media outlets. This is an ever changing situation ( channeling my inner Srain here) and please keep wary. For Wxman 57 or Srain or Andrew, will they send up balloons (at UH and A&M) Sunday or Monday before the event

[wxman57]

No balloon launches are planned (to my knowledge). I don't see the value in launching ahead of the front. Perhaps a launch behind the front at A&M on Sunday evening or Monday morning might help the forecast for Monday afternoon. But by then, it's not much of a forecast time-wise. It would be helpful to have a vertical profile in the cold air to verify model performance.

As for this winter, it's been below-normal here in SE TX but not nearly as cold as I thought it would be (at times). The winter of 1976-77 was looking like a good analog, but the pattern hasn't matched that very cold winter as far as Texas is concerned.

[Andrew]

We are going to launch on here sometime Monday. It's less for the scientific data and more for other reasons. I will try to post the results here when I can.

[srainhoutx]

Evening briefing from Jeff:

Potential for freezing rain across the northern portions of SE TX Monday-Tuesday.

Main focus over the next 72 hours will be the developing potential for a winter storm to affect TX early next week. Strong arctic cold front will move across the region on Sunday with rapidly falling temperatures. Highs in the 60’s and 70’s prior to the frontal passage will tumble into the 30’s by Sunday evening. Latest guidance especially the GFS is trending colder and colder and now only has a high Monday of 33 at College Station and 38 at Houston. An upper level trough will remain back across the SW US allowing significant warm air advection to develop over top of the very cold surface dome. Temperatures only a few thousand above the surface will warm significantly into the 40’s while the surface layer will remain trapped in the 30’s. Forecast soundings maintain this fairly significant warm nose aloft through much of Monday and into Monday night, but slowly cool the surface temperature to near or below freezing north of a line from College Station to Livingston Monday evening into Tuesday morning.

Overrunning pattern will commence post frontal passage on Sunday and continue into at least early Tuesday. A very cold light rain and drizzle is likely Monday into early Tuesday with amounts of .10-.25 of an inch possible across the region.

The main concern is when and where surface temperatures may fall to or below freezing and this presents the potential for freezing rain and ice accumulation. Current guidance suggest the freezing line Monday night will reach into SE TX from College Station to Livingston but could creep as far south as a Brenham to Conroe line. Some of this will depend on if the models are handling the cold air correctly and how much ice/sleet accumulates over N TX Monday.

Current thinking is to change light rain over to freezing rain Monday evening from College Station to Livingston with some ice accumulation possible. Think ground temperatures will be warm from the recent warmth, but elevated objects will likely accumulate some ice with surface temperatures in the 30-32 range. Road conditions will be more problematic as experience last year suggest you really need to get down into the 28-30 range for ice accumulation especially with “warm rain” falling from the warmer air aloft. Ice on bridges and overpasses could be possible from Monday evening into Tuesday morning from College Station to Livingston. Way too early for any estimates on ice accumulation over those northern counties especially since we are over 72 hours out still and much will change over the weekend.

Metro Houston/Harris County:
Currently model guidance suggests temperatures will be above freezing across Harris County Monday night into Tuesday morning which would keep all rain liquid with no ice accumulation. Will need to continue to closely monitor temperature trends over the weekend in the event models trend colder moving the freezing line closer to the metro area.

[niner21]

Well... Got some racing to do up in Decatur TX next weekend and it's showing some wintry garbage next weekend. Any thoughts on next weekend or are we to far out for that ?

Cold we can do, wet and icy aren't good for road racing.