January-Foggy Mornings/Cool & Cloudy To The Month

[srainhoutx]

The 12Z NAM continues to suggest a stronger push of cold air arrives Thursday night into Friday morning. What raises an eyebrow are the impressive pressure readings across Alberta and the NW Territory of Canada. The NAM has a strong upper air disturbance dropping S across Alberta that will usher in another strong front. This 250mb upper air flow as well as the 500mb flow pattern is also concerning as it brings a lot of cold air across the North Pole heading S. Also, another major fly in the ointment is a cold string of High pressure ridging from the Ohio Valley back into Texas with that pesky upper low near the Baja Peninsula. That is typically a pattern we see when we get winter weather events across Texas. As Jeff stated, concern is growing that this threat may be legitimate and we really need to closely monitor things today into tomorrow as more information become available as to what our sensible weather may bring.

[brooksgarner]

Just thinking out loud, but have you guys noticed how the model progs are backing off overall, on the amount of precipitation potential for Friday and especially Saturday? That will be rather important to not lose sight of, if indeed, that is happening... Models want to hold it back until Sunday.

The main band of rain may not get here until the coldest air has already backed away... Of course it only takes a freezing drizzle to mess things up Friday night and Saturday, but as for a major icing event with fallen limbs, powerlines, etc -- beyond it being likely three or four degrees to warm, I'm not seeing "as much" QPF as the model runs in previous days were advertising.

Less rain falling thru an unsaturated column would have a impacts on evaporational cooling potential too, keeping it warmer.

Latest GFS prog in my opinion gives us an "eyeball" 40% chance Saturday... The EURO even less at 20%-30% Saturday, holding it all back for a soaking (but warmer) Sunday. We're talking QPF's around 0.01" Saturday according to the latest run...

GFS SATURDAY EVENING RAINFALL TOTALS:

GFS SUNDAY EVENING RAINFALL TOTALS:

[srainhoutx]

Brooks, typically the Euro is off particularly this Fall and early Winter Season in our part of the world. Case in point... yesterday the Euro suggested QPF amounts of less than a tenth of an inch across Washington DC with their clipper system. Actually the NAM verified much better when it suggested a 2-4 snow event ~vs~ the 'drier models'. I am noticing the IR simulations are becoming a bit more aggressive as the Baja upper low moves E a bit quicker than previously expected. The general pattern this year has been for the more progressive solutions to be correct with these Western upper lows. I suspect that trend will continue with this potential event.

[brooksgarner]

Brooks, typically the Euro is off particularly this Fall and early Winter Season in our part of the world. Case in point... yesterday the Euro suggested QPF amounts of less than a tenth of an inch across Washington DC with their clipper system. Actually the NAM verified much better when it suggested a 2-4 snow event ~vs~ the 'drier models'. I am noticing the IR simulations are becoming a bit more aggressive as the Baja upper low moves E a bit quicker than previously expected. The general pattern this year has been for the more progressive solutions to be correct with these Western upper lows. I suspect that trend will continue with this potential event.

You are right to look at the actual satellite image -- as we all must be careful to keep our heads out of the models when an event is actually happening -- but in my opinion, whether or not the EURO is totally out to lunch, the significant factor to me is that the GFS is now aligning with a generally backing off on total QPF, as those graphics I published illustrate. All that said, all we need is some PVA to zip in here and precip breaks out!

[srainhoutx]

Brooks, typically the Euro is off particularly this Fall and early Winter Season in our part of the world. Case in point... yesterday the Euro suggested QPF amounts of less than a tenth of an inch across Washington DC with their clipper system. Actually the NAM verified much better when it suggested a 2-4 snow event ~vs~ the 'drier models'. I am noticing the IR simulations are becoming a bit more aggressive as the Baja upper low moves E a bit quicker than previously expected. The general pattern this year has been for the more progressive solutions to be correct with these Western upper lows. I suspect that trend will continue with this potential event.

You are right to look at the actual satellite image -- as we all must be careful to keep our heads out of the models when an event is actually happening -- but in my opinion, whether or not the EURO is totally out to lunch, the significant factor to me is that the GFS is now aligning with a generally backing off on total QPF, as those graphics I published illustrate. All that said, all we need is some PVA to zip in here and precip breaks out!

Absolutely. The combination of a PVA for lift and the development of the Coastal trough/wave and their interaction is why they pay you guys the big bucks to offer forecasting analysis.

[BlueJay]

Thanks for all of these updates. I hear a glimmer of hope from Brooks that it may not be as wintry evil this weekend as I thought it may be.
Wait and see.....

[srainhoutx]

Light snow flurries reported at McAlester, OK and in NW Arkansas at Rogers and Harrison.

[Texaspirate11]

I think the models tend to get a bit over dramatic then when all the real info comes in, they back off.
I just don't see how we're going to get the frozen stuff down here by the bay.
IN any event, how many days until Summer?!

[brooksgarner]

Brooks, typically the Euro is off particularly this Fall and early Winter Season in our part of the world. Case in point... yesterday the Euro suggested QPF amounts of less than a tenth of an inch across Washington DC with their clipper system. Actually the NAM verified much better when it suggested a 2-4 snow event ~vs~ the 'drier models'. I am noticing the IR simulations are becoming a bit more aggressive as the Baja upper low moves E a bit quicker than previously expected. The general pattern this year has been for the more progressive solutions to be correct with these Western upper lows. I suspect that trend will continue with this potential event.

You are right to look at the actual satellite image -- as we all must be careful to keep our heads out of the models when an event is actually happening -- but in my opinion, whether or not the EURO is totally out to lunch, the significant factor to me is that the GFS is now aligning with a generally backing off on total QPF, as those graphics I published illustrate. All that said, all we need is some PVA to zip in here and precip breaks out!

Absolutely. The combination of a PVA for lift and the development of the Coastal trough/wave and their interaction is why they pay you guys the big bucks to offer forecasting analysis.

Haha! Well... It's also so we can afford our monthly subscription to the Psychic Friends Network -- you know, for the forecast

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[don]

Latest gfs backs off on the cold air and precipitation fwiw

[Heat Miser]

Latest gfs backs off on the cold air and precipitation fwiw

Ahhhh hahaha. It will be spun, just wait.

[ronyan]

Latest gfs backs off on the cold air and precipitation fwiw

12z GFS did not back off on cold from what I can see.

[Portastorm]

Latest gfs backs off on the cold air and precipitation fwiw

12z GFS did not back off on cold from what I can see.

Yeah, I was just going to write that. The 12z GFS is a few degrees warmer for the Houston area during the day on Saturday. But Saturday morning, it is actually a bit colder than the 0z run. It does delay the onset of heavier precipitation by 6-12 hours for much of South Texas and that could be why the 12z run looks a tad warmer during the day on Saturday. Regardless, we had a trend of several days showing the potential for wintry precip for portions of south central and southeast Texas. This is one model run which is a bit different. If the 12z Euro comes in supporting the 12z GFS then it might be something to put weight in. If the 18z or tonight's 0z GFS go back to earlier ideas, then it would be clear that today's 12z run was a "bad" run. We shall see.

[don]

Latest gfs backs off on the cold air and precipitation fwiw

12z GFS did not back off on cold from what I can see.

Yes it's just as cold what I meant to say is once precip starts the temperature is warmer than in previous runs

[brooksgarner]

Precip does back off significantly in the last three GFS runs compared to days earlier. This doesn't mean much overall because the system has yet to even develop... This also falls inline very well with the EURO, holding off on almost all measurable rain until Sunday.

Pulling my head out of the models, if we get some good PVA interacting with the resident Gulf moisture, plus the arctic air is a few degrees colder than currently forecast (as it well, may be), we could easily see some icing on bridge and overpasses, especially north of HWY 105 -- even with some freezing drizzle. Then again, if the arctic air doesn't quite come together and the rain holds off, this could be a total nonevent. I give it equal chances!

All that said, one model (ADONIS, run by WSI) forecasts freezing rain Friday morning, while WIS's "RPM" model forecasts rain. Typically the RPM is much more accurate. It's a higher res model.

As I said before, we won't know for sure until it begins.

See you at Noon on KHOU 11!

ADONIS:

RPM:

[Portastorm]

Latest SREF (9z) shows a mix of freezing rain and sleet for Austin from early Saturday morning until at least Saturday evening. The run ends at 6 p.m. where it is still coming down.

[texoz]

It may or may not be interesting to note that here in Austin the temps are warmer than forecast. It's 49 at Mabry at 11:30am. Yesterday, I think the forecast high was low 40s. Front has moved through now so temps will start falling.

I'm guessing this means front moved a little slower than forecast 24hrs ago.

[brooksgarner]

Pre-Frontal compressional heating... same thing happening here in Houston. It's 60° as of Noon. Still, this will have little effect on the intensity of the changing air mass. It'll be cold in just hours...

[srainhoutx]

The Euro cuts back on the precipitation further N along the Red River and the Dallas/Ft Worth Metroplex. In Central and SE Texas into SW Louisiana, there is a bit more potential of 'moisture'. The Canadian suggested freezing precipitation in the Del Rio to San Antonio area Saturday morning and very close to Austin as well. Of coarse the Canadian develops a full blow Coastal Low which none of the other reliable guidance has been indicating.

[brooksgarner]

Obviously subject to change with a complicated weather pattern like this ... But, at the very least we're looking at some chilly days in Houston ahead.

What your gut feeling about our freezing rain chances?

7-Day as of 1/7/15