Texas Winter 2015-2016

[northjaxpro]

The GFS for the past few runs is showing a pretty significant large-scale pattern change across North America just before Christmas, still way out in the long-range though:

http://i.imgur.com/S4Dib85.png

GFS is also showing a much more stromier pattern as well heading towards Christmas and the last week of December. It is way out though (2 weeks), but possibly a signal of seeing a stormy, wet and active southern stream jet across the South and Gulf Coast region Christmas time.

[TheProfessor]

:roflmao:

http://www.tropicaltidbits.com/analysis ... cus_40.png

Can we just accept this as fact and call it a day?

Only if we are allowed to expand those bright orange colors eastward.

[TeamPlayersBlue]

I think the best way we will get snow is by a particular pattern this year. I cant remember what its called but it has the backward 'S' setup in the 500MB chart. The massive arctic break was showing a 'backward S' type of setup but the high pressure was to far north. This could create a large up[per level low to dig southward with this type of setup with lots of cold air trapped within it.


Edit: So now by looking at the Canadian, this is the setup im talking about lol. I honestly dont trust the canadian, but i think this is the type of setup we need.

[TheProfessor]

I think the best way we will get snow is by a particular pattern this year. I cant remember what its called but it has the backward 'S' setup in the 500MB chart. The massive arctic break was showing a 'backward S' type of setup but the high pressure was to far north. This could create a large up[per level low to dig southward with this type of setup with lots of cold air trapped within it.

"Backward S" is the McFarland signature I believe.

[northjaxpro]

It is the McFarland Signature

[Brent]

:uarrow: It is the McFarland Signature

Yeah... that happened right before the icemaggedon in DFW in 2013 too... there's a lot of things written about it to say the least...

White Christmas chances on the Euro ensembles

[Ntxw]

McFarland's Signature = Severe -EPO.

3 Ingredients needed is per his paper

1. Extreme Blocking into NW North America/Alaska (I like to use 560+dm at 500mb as abnormal)
2. Negative PNA
3. Baffin/Davis Straits Vortex

The AO and NAO are irrelevant to such set ups. They can be negative or positive.

[gpsnowman]

That is a strange looking Christmas snow chance map. Notice the Midwest all the way up to Green Bay and points southwest, east, and southeast. A lot of yellows where the chances usually are much higher. Of coarse this all could change between now and then. El nino city.

[Brent]

Speaking of el nino city... this is crazy:

If the CMC happens to not be on drugs we'd be ahead of a lot of cities on this chart...

[KatDaddy]

Near record temps across SE TX today. The SPC has shifted the slight risk area to N TX, OK, and S KS tomorrow while a marginal risk area exists across Central, E, and SE TX. In addition, this morning's Houston-Galveston AFD mentions the possibility of a Flash Flood Watch with some areas seeing 4-6" totals by Sunday morning due to deep tropical moisture. It may be December but it feels like April.

[Big O]

Near record temps across SE TX today. The SPC has shifted the slight risk area to N TX, OK, and S KS tomorrow while a marginal risk area exists across Central, E, and SE TX. In addition, this morning's Houston-Galveston AFD mentions the possibility of a Flash Flood Watch with some areas seeing 4-6" totals by Sunday morning due to deep tropical moisture. It may be December but it feels like April.

Not sure if anyone has posted this, but here is the latest (12.07.15) from Judah Cohen:

The AO is currently positive and is predicted to trend negative but still remain near neutral.

The negative AO trend is reflective of the model forecast of initial low pressure/geopotential heights over the North Atlantic side of the Arctic transitioning to more high pressure/geopotential heights. Though the models are not predicting necessarily cold weather it should result in damping of the large positive temperature anomalies for Europe, western Asia and the Eastern United States.

However the models predict low pressure/geopotential heights to continue on the North Pacific side of the Arctic. This will likely result in any cold weather being focused in Western North America for much of the remainder of December.

Models are predicting an increase in energy transfer from the troposphere to the stratosphere starting the third week of December. This will likely lead to perturbation of the polar vortex during the latter half of December. The more the vortex is perturbed, the higher our confidence in a cold second half of winter.

Longer-term high latitude boundary conditions favor a negative bias to the AO including extensive Eurasian snow cover and low sea ice extent in the Barents-Kara seas. The key will be how strong the energy transfer from the troposphere to the stratosphere is in late December and how much the polar vortex is perturbed. If the energy transfer does not significantly weaken the polar vortex, the AO will likely remain mostly positive and mild temperatures will dominate the mid-latitudes.

If the -AO materializes as Cohen suggests and combines with a -EPO (preferably a severely negative EPO), then look out.

[Tireman4]

Near record temps across SE TX today. The SPC has shifted the slight risk area to N TX, OK, and S KS tomorrow while a marginal risk area exists across Central, E, and SE TX. In addition, this morning's Houston-Galveston AFD mentions the possibility of a Flash Flood Watch with some areas seeing 4-6" totals by Sunday morning due to deep tropical moisture. It may be December but it feels like April.

Or May...LOL..ughh..this morning was the pits...ugghh..my bike ride was ughh

[gboudx]

Update from jeff:

Heavy rainfall and severe weather possible this weekend.

A strong storm system will move into TX over the next 48 hours resulting in a good chance of rainfall and thunderstorms. Upper level trough along the US west coast will dig into the SW US and intensify over the next 24 hours. This will in turn lead to an increase in moisture advection across TX with the formation of a 45-55kt low level jet by tonight. Lead short wave trough will eject out of the main trough Saturday afternoon and spread lift across a moist SE TX air mass. Expect numerous thunderstorms to develop ahead of this feature post noon Saturday into the evening hours. Some of these storms could be strong with strong winds. Heavy rainfall will also becoming increasingly likely as PWs soar into the 2.0 inch range which is over the daily record values for both LCH and CRP for this time of year.

Expect a brief break late Saturday evening followed by a second round of storms Sunday morning ahead of the main trough axis and cold front. Low level shear values are favorable for low level storm rotation Saturday night, but instability is generally low. Cannot rule out a few damaging winds or tornadoes in this setup as cold season events near the Gulf coast don’t require much instability to produce severe weather. Air mass will certainly support heavy to excessive rainfall with potential for a period of cell training from near Matagorda Bay to Huntsville. A little concerned about the forecasted very high PW air mass with the strong lift and potential for training. May need a flash flood watch at some point if confidence in cell training increases.

Expect storms totals of 1-3 inches with isolated amounts of 4-6 inches. While grounds have had a bit of time to dry over the last several days…they are generally still soggy and rainfall of this magnitude will result in run-off. Main concern is for area rivers which are already high and given the expected widespread rainfall amounts, especially over the Trinity and Brazos basins additional rises will be possible into next week. High hourly rainfall rates will also likely present a urban flood threat with respect to street flooding.

Hydro:
Flood control operations have begun on both the Trinity and Bazos River basins to help evacuate high storage pools in area reservoirs due to the upcoming rainfall event. Basin average amounts over the next 48-hrs will almost certainly lead to additional main stem rises on the Trinity and Brazos basins and additional flood gate operations at area lakes and reservoirs.

Extended:
Pattern looks to be transitioning back to active with another storm system coming in stronger in the models by the middle of next week which may also grab a good shot of cold air.

[Ntxw]

Longer-term high latitude boundary conditions favor a negative bias to the AO including extensive Eurasian snow cover and low sea ice extent in the Barents-Kara seas. The key will be how strong the energy transfer from the troposphere to the stratosphere is in late December and how much the polar vortex is perturbed. If the energy transfer does not significantly weaken the polar vortex, the AO will likely remain mostly positive and mild temperatures will dominate the mid-latitudes.
[/color]
If the -AO materializes as Cohen suggests and combines with a -EPO (preferably a severely negative EPO), then look out.

Wave 1 from this monster by Sunday will disturb the strong stratospheric Polar Vortex (last night's Euro had it down to 922mb which would be a record). We can see it dip the AO negative in the medium range. We'll need wave 2 from the Atlantic, and maybe even wave 3 from NW Asia to really take down that mighty PV for a sustained -AO. Wave 1 though will definitely be Pacific helped EPO response.



I'm going to run a re-analysis on 1972 and 1965. These two years are being thrown around with eastern ridge/warmth and western cold for December.

[wxman57]

I'm seeing tremendous differences in the main global models beyond about 72 hours. That doesn't give me much confidence in the forecast beyond this coming weekend.

[Big O]

Longer-term high latitude boundary conditions favor a negative bias to the AO including extensive Eurasian snow cover and low sea ice extent in the Barents-Kara seas. The key will be how strong the energy transfer from the troposphere to the stratosphere is in late December and how much the polar vortex is perturbed. If the energy transfer does not significantly weaken the polar vortex, the AO will likely remain mostly positive and mild temperatures will dominate the mid-latitudes.
[/color]
If the -AO materializes as Cohen suggests and combines with a -EPO (preferably a severely negative EPO), then look out.

Wave 1 from this monster by Sunday will disturb the strong stratospheric Polar Vortex (last night's Euro had it down to 922mb which would be a record). We can see it dip the AO negative in the medium range. We'll need wave 2 from the Atlantic, and maybe even wave 3 from NW Asia to really take down that mighty PV for a sustained -AO. Wave 1 though will definitely be Pacific helped EPO response.

http://i66.tinypic.com/21ooozr.png

I'm going to run a re-analysis on 1972 and 1965. These two years are being thrown around with eastern ridge/warmth and western cold for December.

I am really liking 1965-66 as an analog. Mid-January through March could get interesting.

[Ntxw]

I am really liking 1965-66 as an analog. Mid-January through March could get interesting.

1965-1966 was one of the rare cases where there was warmth in the North Pacific, near the Aleutians vs typical El Nino cold water, that caused ridging to get Canada very cold in January thus the resulting severe cold of Jan 1966.

[Ralph's Weather]

Waves of monster Bering Sea lows is going to dynamically pump up the EPO ridge along with breaking down the PV, in previous seasons (especially 2013/2014) the EPO ridge was driven by very warm GoA waters. Atlantic help would be nice.
Expect crazy weather later this winter as it appears that we are living in a climate of extremes right now.

[WeatherNewbie]

I'm seeing tremendous differences in the main global models beyond about 72 hours. That doesn't give me much confidence in the forecast beyond this coming weekend.

What do you think is causing the large discrepancies?

[Ntxw]

I was looking around at various stations across the country and just look at these warm departures. In 4 days we will be halfway through December, some of these will get warmer by weekend' end. Many all time December warm records will fall at these stations.

Green Bay, WI - +13.2F
Marquette, MI - +12.5F
Minneapolis, MN - +12.6F
Chicago, IL - +8.4F
Indianapolis, IN - +4.7F
Columbus, OH - +3.6F (TheProfessor is one of the cooler warm spots in the midwest )
Philadelphia, PA - +7F
NYC, NY - +7.5F
Boston, MA - +6.4F
Washington, DC - +4.3F

And the whopper

Minot, ND - +21.4F


And to think here we were back in 2011/2012 complaining about our monthly average departures between +2 and +3s

A term some of used here "El Nino City"