January 2016: Mardi Gras WX Outlook

[srainhoutx]

In the past having as much snow on the ground, in such close proximity, as we do...well let's just speculate. 1st does this inhibit the moderation of temperature up stream? 2nd, as the next front comes thru by around the 1st of Jan, do the models not pick up on the lack of moderation and therefor over do the forecasted temperature?? 3rd, how does that effect the dew point? 4th, if the colder air coming in is shallow is it deep enough for sleet or will the warm nose aloft erode the cold air enough to just be a cold rain that actually holds the temperature up? Maybe so of you real weather guys can help out here??? Thanks!

First off, Welcome BigThicket. We are glad you found us. To your first question, that is somewhat of a wildcard regarding upstream moderation. The West and the Rockies into the Southern Plains have snow on the ground, thus typically we see less moderation. Our source Region of Western Canada has been 'warmer than normal', but there is abundant snow across Canada. For example Yellowknife was -33C this morning. That is fairly chilly. What typically allows a warm nose is the warmer air streaming in off the Eastern Pacific with the sub tropical jet. The guidance is hanging the upper low much further N in the Great Basin versus the bowling ball cold core upper low that just exited our Region. I see the NWS offices to our West are indicating a wintry mix during the overnight hour of Thursday into Saturday, depending on the timing of the disturbance moving across our area. Right now I think a chilly rain is the most likely solution, but that may change as we near the Wednesday timeframe and see just how much cold air is associated with the Thursday front.

I am carefully watching the mid January timeframe as the upper air pattern could become much more conducive for much colder air entering the Lower 48, particularly along and East of the Continental Divide. The 12Z guidance in the longer range are really 'hinting' of a blocking regime with a strongly +PNA (Western Ridge) nosing well into the Arctic. That and a crashing Arctic Oscillation (-AO), -EPO as well as other indicators suggest a total breakup of the current Polar Vortex structure over the Arctic Circle allowing the potential for a cross Polar flow to develop driving very cold air from Siberia into North America. There are some indications that the Polar Vortex will setup shop near Hudson Bay in Canada favoring that cross Polar flow. Typically it takes a couple of weeks for the pattern to fully transition. That would put us into the mid/late January timeframe. For now, we will wait, watch and see exactly how the pattern evolves.

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[BigThicket]

Joe Bastardi alluded to this mid Jan. Connection of cross polar flow as well...and thanks for the explanation!

[DoctorMu]

It looks like the various reliable computer schemes are coming together suggesting another Great Basin upper low with a rather robust disturbance riding the sub tropical jet out of the Eastern Pacific will bring a round of light precipitation, mostly in the liquid form across the Western and Southern half of Texas. There is growing indications that a Coastal wave may develop S of Brownsville enhanced by the approaching disturbance over Mexico may allow over running moisture over a shallow cold dome of High Pressure keeping things dreary as we ring in the New Year.

What are the chances of "non-liquid" precipitation in the Austin area?

As of today I believe that areas near Del Rio, Kerrville and perhaps San Angelo have the 'best' chance of any wintry mischief. That said we are more than 5 days out and as we just witnessed, things change quickly. Hopefully by Thursday we will have a better idea as the various features near North America and we see just how much of an influence all that snow across W Texas, New Mexico and the Panhandle has on our sensible weather forecast.

on cue:

[jeff]

The simple answer to your first question is yes...if snow is still widespread and on the ground over NW TX come late week, but I think that may be a stretch since daytime temperatures will be above freezing the next few days.

Two: models may or may not fully grasp snow cover on the ground and the impact on downstream temperatures in a cold air advection pattern

Three: The colder the air...generally the lower the dewpoint. Snow cover does not have a great affect on dewpoint since the air flowing over it is usually dry (low dewpoints).

Four: All current model indications for this weekend are for mid and even low level temperatures to be above freezing locally...hence all rain. Top down saturation method is best for any overruning event and one could in turn cool the surface dewpoit through evaporative cooling, but even the forecasted dewpoints this weekend are in the mid and upper 30's...which is still just a cold rain. Westward where the air may be a bit colder and dewpoints a little lower does leave a slight potential for some sleet or light freezing rain during the morning hours Friday and Saturday.

[BigThicket]

Well that's pretty black and white...lol...thank you Sir!

[GBinGrimes]

As for snow cover...drove to Montana on the 18th and 19th via the "typical" route up I 25 through Colorado and Wyoming and then through Billings to Bozeman and down to Big Sky. From Colorado Springs and all the route north of that, its as white as a clean diaper. On the route back, attempting unsuccessfully to beat "Goliath", we went through Wyoming, Idaho, Arizona and New Mexico and then spent 12 hours packed in a mega miles long sardine can of vehicles near Kent, TX before turning around and finding nice, clear roads on 90 thru Marfa, Alpine and Del Rio to reconnect back to I 10 in San Antonio. There is plentiful ground cover snow all the way into Northern Arizona. Just beautiful an very, very cold. We hit minus 16 in West Yellowstone on the morning of the 26th, so Old Man Winter is lurking to our north.

Never before had I or my son driven through a rage of blowing snow, which we encountered near Sheridan, WY and also near Billings. Folks, that is scary. Thank God the road crews up north know what they're doing and kudos to them.

It will be interesting to see how Canadian and possibly Polar air modifies when it begins to venture south. America is a beautiful place. The drives were at times white knucklers and tenuous but oh the views and scenery!

[srainhoutx]

The overnight guidance continues to advertise a breakdown of the Polar Vortex across the Arctic Circle and a classic +PNA/-AO Pattern in the extended range. A cross Polar flow is depicted with the Polar Vortex beginning to take shape near Hudson Bay. The ECMWF and GFS schemes suggest a developing Western storm system moving onshore across Southern California into the Desert SW. Ridging builds well into Alaska as a 1045mb+ Arctic High develops from Siberia into the Arctic suggesting the bridge of flow from Siberia into the Canadian Prairies becomes more pronounced. The top Climate Prediction Center Day 11+ Analogs issued yesterday have January 1985. Some may recall that record snow fell across San Antonio into Austin during that year. While it is way too soon to forecast another such event, the analogs can assist the forecaster with similar upper air patterns that could be capable of offering clues to what our sensible weather may bring.

[MontgomeryCoWx]

Latest from Cosgrove echoes srain...

The most recent runs of the Canadian and European ensemble packages show potential for cross-polar flow and a Siberian intrusion, as well as the threat for a significant, or worse, winter storm affecting Texas, the Old South, Appalachia and the Eastern Seaboard. Cold air makes its first meaningful push January 6-8; the chance for widespread snow and ice (maybe rain thunder along the coastlines) is targeted for January 10-14. Given the impressive stratospheric warming event and inputs from tropical forcing, I suspect this tendency for widespread cold and increased frozen precipitation is going to be around for a long while.

[srainhoutx]

Morning briefing from Jeff:

Cold air mass firmly entrenched over the area…will continue for the next several days.

Cold surface high pressure that has built over TX behind the departing weekend storm system will begin to shift eastward today allowing moisture to surge over top of the surface cold dome. Clouds have already increased overnight and expect a continued thicken and lowering of the cloud deck today as moisture increases above the surface. A short wave over the SW US will move across the southern plains tonight dragging another cold front across the area on Wednesday. Will likely see just enough moisture for drizzle and light rain tonight especially along the coast and offshore.

Much colder air mass filters into the region on NYE and NYD with continued SW flow aloft brining Pacific moisture across the area. A stronger short wave within this sub-tropical flow moves toward the area NYD and next weekend with cold air locked in place at the surface. Rain chances will start to increase late NYE and continue into NYD and at least most of Saturday if not early Sunday. Will need to keep a close watch on dewpoints and surface temperatures Friday morning, Saturday morning, and Sunday morning across our north and western counties for any potential for a mixture of winter precipitation. Current model soundings and forecasted temps/dewpoints should keep everything liquid, but potential for rain mixed with sleet and snow will be possible by Friday night over portions of the Hill County into central TX. Highs on Friday and Saturday will likely remain in the 40’s over the entire area, possibly even the upper 30’s across our northern counties.

[ticka1]

for those of you who know and follow Larry Cosgrove - here is his latest post.

The most recent runs of the Canadian and European ensemble packages show potential for cross-polar flow and a Siberian intrusion, as well as the threat for a significant, or worse, winter storm affecting Texas, the Old South, Appalachia and the Eastern Seaboard. Cold air makes its first meaningful push January 6-8; the chance for widespread snow and ice (maybe rain thunder along the coastlines) is targeted for January 10-14. Given the impressive stratospheric warming event and inputs from tropical forcing, I suspect this tendency for widespread cold and increased frozen precipitation is going to be around for a long while.

something to keep any eye on hoing into january and 2016.

[Heat Miser]

Based on February 2011 and onward, I'll remain cautiously optimistic. Until wx57 jumps on board; my prediction, based on many years of living in this area, will be cold rain/drizzle for Harris County southward. It will be miserably cold and damp. There will be a warm layer aloft which keeps all our precipitation liquid.

[wxman57]

Based on February 2011 and onward, I'll remain cautiously optimistic. Until wx57 jumps on board; my prediction, based on many years of living in this area, will be cold rain/drizzle for Harris County southward. It will be miserably cold and damp. There will be a warm layer aloft which keeps all our precipitation liquid.

That appears to be a reasonable assessment of New Year's - miserably cold and wet. With the freezing line predicted to be way up above 10,000 ft, a cold rain appears to be in store for Houston Friday/Saturday.

[BigThicket]

Bastardi still preaching cold getting colder...by mid month we will be much colder with an active sub-trop jet turning things nasty for the south. Seems to be a fairly wide felt opinion of our weather to come. He has drawn comparisons to 1997 as things make s move to get going in the last half of January through Febuary even extending well into March. Not real sure of the significance of 1997...I have not looked back at records for that year and I have slept since then. I'm sure their is somebody on this forum that can opine. This weather community is like a weather Google machine! Lol

[srainhoutx]

Bastardi still preaching cold getting colder...by mid month we will be much colder with an active sub-trop jet turning things nasty for the south. Seems to be a fairly wide felt opinion of our weather to come. He has drawn comparisons to 1997 as things make s move to get going in the last half of January through Febuary even extending well into March. Not real sure of the significance of 1997...I have not looked back at records for that year and I have slept since then. I'm sure their is somebody on this forum that can opine. This weather community is like a weather Google machine! Lol

January 12/13, 1997 brought a significant ice storm across SE Texas/SW Louisiana. The synoptic set up for the event started with a warm January 1st and 2nd followed by an Arctic Front around the 5th, if I recall correctly. A cold rain set in around the 8th and chilled the ground temperatures to around 40F. A robust upper air disturbance moved across Central Texas and wet bulbing brought sleet to College Station and Houston. Freezing rain developed from College Station to Houston on the 12th spreading E into Beaumont and Lake Charles. Light freezing rain continued into the 13th before drying out. I recall extensive power outages across SE Texas and SW Louisiana. The afternoon Update from the Climate Prediction Center does show January 12, 1997 as the second Analog date in the Day 11+ Analogs. I also see January 1985 and January 1994 in those analog synoptic upper air patterns.

A quick look at the Teleconnection Indices as well as the Sudden Stratospheric Warming guidance as well as the MJO Phase 7/8 progression suggest the pattern may well be conducive for cold and wet weather across the Region. The 12Z ECMWF seem to also suggest a split of the Polar Vortex occurring as we near the 8th/10th timeframe. We will see if the pattern does indeed deliver a Wintry Pattern for our Region.

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[Heat Miser]

For those wishing for freezing temps and precip...be careful what you wish for. Around here that equates to freezing rain and all that misery, not snow.
I'm all for snow, but being a realist I know what we usually get in the greater Houston area.
One thing's for sure, winter is here and it's going to stay a while. Already miss the 80 temps.

[wxman57]

In the 12Z GFS I was looking for any signs of cross-Polar flow. At 384hrs, it has flow from NW Canada and a Polar low over the Great Lakes and SE Canada, but no indication of cross-Polar flow. That kind of pattern (with an active southern stream) would mean cold and wet for Texas. Add in a little colder air later in January or in February and we could see some snow/sleet down here in SE TX. Remember, February is typically Houston's snowiest month.

[BigThicket]

Like I said...weather Google! Lol...you guys rock. I will say this; I have bounced around different weather forums and you guys are all business. I felt like I knew a good deal about weather hanging around the other forums but you guys are on another level with the processing of information and then redistributing it in a true readable form. Back to 1997...I remember now...lol that was the year my son was hatched, just did not put it together, but your dead on, no power and cold!

[BigThicket]

Just FYI if you go to weatherbell.com you can look at Joe Bastardi's video and his explanation of connection in the coming days...this is a set up of types because I really need one of you guys to watch it and explain. I understand some but he gets pretty scientific...in specific I just wanted to know the difference between what he is discussing and cross polar flow???? Maybe one of you guys will have few minutes later on. Thanks a million!

[Heat Miser]

Interesting. For $185 per year you'd think that site would explain things in such a way that anyone could understand? Admittedly, Joe gets extremely, let's say, technical in his analysis. But hey, that's a guy who has many years experience.
But if I'm going to fork over $185 per year I want it explained very, very adequately. I'll betcha Srain can answer that cross polar flow question for you, and for free.
Well look what I found on the Google highway.

Cross Polar Flow-

The atmospheric setup when the jetstream crosses the north pole and continues nearly straight south into the US. This setup generally produces the coldest air outbreak possible for the central US.

[BigThicket]

Well just FYI...I'm cheap and only watch his free daily updates as well as his free Saturday update that is usually pretty lengthy...TBH...$185.00 goes a long ways to help with kids in college as far as gas or extra spending money ect...so I guess I can't gripe about how technical the lingo is when it's free. But hey not a problem now because I found you folks! Thanks Heat Miser for the Google help, guess I should have exercised my googleyness!