January Weather Discussion: Slight Chance Severe Storms

[southerngale]

That's what the gfs does. Just like last year over 240. He's it shows either extreme cold or snow but with each run the 10 days is always 10 days away....if we could only get to day 10.. its like the twilight zone model..but what's really. Weird is why it always shows us having fun after day 10 I thinks its a ponze scheme

I was just saying on s2k last night that our snowfall fun seems to always be 10-15 days away.

[srainhoutx]

The 12Z NAM is painting a mighty wet Saturday/Sunday across the Lone Star State. That model also suggests possible wintry weather in parts of N TX as the Upper Low and surface low in the Gulf begin to shift E.

[wxman666]

Sitting outside at Starbucks right now. Currently 40 in Cypress. Fingers are stiff, making it difficult to type on my iPad's keypad. I'm sitting here thinking, "God, the arctic air hasn't even hit yet and it's this cold! I shutter to think what next week will feel like!"

[srainhoutx]

Morning e-mail from Jeff just arrived...

Much to talk about this morning in the middle and extended portions of the period.

Cut-off upper low off the southern CA coast has pulled up stationary and will begin to move eastward later today. Massive plume of mid and high level moisture south of this system currently extending from the central Pacific to NC MX will swing eastward into NE MX and TX over the next 24-36 hours. Approaching upper level system will induce surface pressure falls over SW TX late Saturday afternoon with surface low pressure forming in the region from the Big Bend to Laredo. Strong warm air advection will ensue into this system with a warm front moving toward the coast and possibly inland Saturday evening. Large scale lift with the upper level storm will begin to affect the area by Saturday evening resulting in the formation of showers across the entire region and thunderstorms over the Rio Grande plains.

Big show appears to be in store Saturday night-Sunday as surface low deepens over SC TX and pushes over the upper TX coastal counties from Matagorda Bay to Galveston Bay Sunday. Appears the warm front will move just inland of the coast…possibly to US 59 ahead of the surface low. Forecasted low level winds south of this boundary are strongly backed to the E or ESE with rapid veering of the winds to the SW in the mid levels supporting strong low level wind shear favorable for updraft rotation and supercell storm structures. Current limiting factor for a significant severe weather/tornado outbreak appears to be the amount of instability with progged indices of around 1000J/kg south of the warm front. With all that said, still expect isolated severe weather along and south of the warm front early Sunday morning with potential for damaging winds and an isolated tornado.

North of the warm front a cold rain as low level NE winds wrap in cold air over NE TX and N LA into the system. Expect temperatures south of the warm front to rise into the 60’s while north of the boundary temperatures will remain in the 40’s all day Sunday with widespread rain. As the surface low deepens and moves east of the area strong offshore flow will develop drawing the cold air mass southward. Slower upper trough ejection will bring a chance of showers across the area behind the main surface low keeping rain chances into Sunday afternoon. Low level cold air advection will drive temperatures into the low to mid 30’s over our northern counties by Sunday evening, but at this time it appears the moisture will be east of the region before the onset of any freezing at the surface.

Widespread rainfall of 1-2 inches appears likely with this system, although I am becoming a little concerned about the warm front placement as these features tend to focus and train excessive rainfall. Additionally, the placement of this boundary by early Sunday morning could be close to US 59 where excessive rainfall fell on the 29th of Dec resulting in heavy rainfall over wet/soggy grounds. A few locations near the warm front could see 3-4 inches of rainfall.

Early Next Week:

Much talked about arctic front still on tap to bring very cold air to the region starting late Monday. Suspect clouds will linger much of Monday behind the departing Sunday system keeping highs in the 40’s on Monday even prior to the arctic invasion. Large 1055mb arctic high will begin to surge down the plains Sunday reaching the TX coast late Monday. May need a faster timing with this boundary as such cold dense air masses tend to move very quickly southward. Very strong cold air advection will ensue post boundary by Monday night with NW winds of 20-30mph and possibly higher along the coast. Temperatures will rapidly fall from the 40’s into the 30’s and possibly upper 20’s by Tuesday morning. Models are bouncing around with the idea of keeping clouds in the area at times Tuesday and Wednesday and this will have big effects on overnight lows and afternoon highs in the post frontal air mass. Will continue the trend yesterday of undercutting the GFS guidance numbers by several degrees from Tuesday onward. Will go with lows in the upper 20’s for Tuesday morning (even with strong winds and clouds) and highs only in the low to mid 40’s. For Wednesday will go with lows again in the upper 20’s (could see lower 20’s if skies clear) and highs in the upper 30’s to near 40. Thursday will go with lows in the upper 20’s and highs in the low 40’s. GFS tries to generate some light precipitation by Thursday of next week in the cold air mass, but not confident that this will occur.

Possibly some warming Friday and Saturday of next week before another surge of very cold arctic air arrives late next weekend. Next week to week and a half will feature well below normal temperatures across the entire state. In fact highs may run 15-20 degrees below normal.

[wxman57]

Upper 20s is certainly not impressive as Arctic air goes. Still many uncertainties until that cold air is actually there in NW Canada.

[harpman]

I was just about to post that I will feel a lot more confident about all of this once we can see that cold air actually up in Canada.

[randybpt]

I looked.at the 7 day for yellowknife canada the lowest reading in 7 days there is -34 c which is not.all that unusal for them. I think we will have a run of below normal temps next week and half but nothing extreme just some.good old winter days then after that who knows.

[redneckweather]

I'd have to agree with you wxman. If mid to upper 20's is all we see next week for lows, then that is not impressive at all by arctic air standards. Don't get me wrong, it's gonna be mightly chilly but it looks like last January's cold snap will be colder than this one.

I see this Jeff guy forecasting low's in the mid to upper 20's and the high's around the 40 degree mark under a strong northwest flow. I will tell you one thing and you can take it to the bank...if cloud cover sticks around and is thick, high temps on these days will NOT stray far from the low temps. That will make for some very raw day time weather.

[srainhoutx]

OK, the 12Z GFS is running and I've poured another cup of coffee. Let's see what the models spit out today...

[ronyan]

I looked.at the 7 day for yellowknife canada the lowest reading in 7 days there is -34 c which is not.all that unusal for them. I think we will have a run of below normal temps next week and half but nothing extreme just some.good old winter days then after that who knows.

The colder air hasn't moved into Canada yet.

The NWS right now shows lows in the mid 30s next week, that's pathetic for arctic air in my book. They will probably lower those numbers some as we get closer.

[snowman65]

Upper 20's isn't any colder than it has gotten this winter.......

[ronyan]

Upper 20's isn't any colder than it has gotten this winter.......

Yeah I really hope it's a little lower than that. The bigger story may be the low high temps if we have cloud cover.

[redneckweather]

OK, the 12Z GFS is running and I've poured another cup of coffee. Let's see what the models spit out today...

Shoot, I'm at my office now and don't have the GFS model site bookmarked here.

[wxman666]

OK, the 12Z GFS is running and I've poured another cup of coffee. Let's see what the models spit out today...

Drinking a toffee mocha myself. Busy day between computer software updates and watching forecasts and models. Houston...we are go! Let's rock this storm!!

[srainhoutx]

OK, the 12Z GFS is running and I've poured another cup of coffee. Let's see what the models spit out today...

Shoot, I'm at my office now and don't have the GFS model site bookmarked here.

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/

[redneckweather]

Thank you sir!

[srainhoutx]

Through hour 72 hours, the GFS paints a very wet Sunday across TX. Heavy rainfall across Coastal TX and a possible MCS. Heights rising across AK. 1048 mb high in NW Canada.

[srainhoutx]

@ 84, light snow from the Canadian front range down into KS/OK/NE TX/AR. 1049mb high in NW Canada. 0 degree 850 drapped across the Red River and points E.

[srainhoutx]

@ 108, 1050mb high showing in the Yukon. Heights continue to build in AK. Front is racing S into the Panhandle. Front range snow in CO/KS/OK/TX Panhandle.

[srainhoutx]

@ 120, front has cleared Coastal TX. 1050mb high extends from Western Canada into the Lower 48. 1045mb high in KS. CAA is rather strong. Some possible light precip in the Hill Country where the 0 degree 850's are heading S.