Texas Winter 2018-2019

[rwfromkansas]

With these extremely marginal setups, I have learned to not even model check until a day or two before. Honestly, I would even take some mood snow with melting flakes and no accumulation.

[orangeblood]

Lots of rumblings going around about the potential Major Strat Warming Event being forecast by the Global Models (GEPS is forecasting a 50-60 Deg C warming event at 10mb over the pole) ....if this were to occur around the time forecast, 2nd half of Dec, this points to some pretty severe US January s - particularly 1966 1985 and 1994!

[Sambucol]

Lots of rumblings going around about the potential Major Strat Warming Event being forecast by the Global Models (GEPS is forecasting a 50-60 Deg C warming event at 10mb over the pole) ....if this were to occur around the time forecast, 2nd half of Dec, this points to some pretty severe US January s - particularly 1966 1985 and 1994!

https://www.tropicaltidbits.com/analysis/models/gem-ens/2018121012/gem-ens_Tz10_nhem_31.png

What kind of temps in Southeast Texas with that setup? Thank you.

[South Texas Storms]

Yall north Texans have gotta be loving the 18z NAM.

[orangeblood]

Yall north Texans have gotta be loving the 18z NAM.

Yep, really starting to bring in the cold advection down to the surface on the backside of the ULL!

[Haris]

Lol

[weatherdude1108]

Lots of rumblings going around about the potential Major Strat Warming Event being forecast by the Global Models (GEPS is forecasting a 50-60 Deg C warming event at 10mb over the pole) ....if this were to occur around the time forecast, 2nd half of Dec, this points to some pretty severe US January s - particularly 1966 1985 and 1994!

https://www.tropicaltidbits.com/analysis/models/gem-ens/2018121012/gem-ens_Tz10_nhem_31.png

What kind of temps in Southeast Texas with that setup? Thank you.

1985 was an all-time record snowfall year in San Antonio, the likes of which tested the city like it had never been tested. The city did not own any snow/ice removal equipment. Shut down the town. I was there.
I was a kid. Played happily, enjoying time off from school. Could it happen again? Maybe further north? We'll see. I always waited with anticipation for that to happen like that again, knowing it was possible. But then weeks, then years/decades went by, and nothing to that magnitude has ever happened (at least at this time, so far).

[Brent]

And still snowing here

[JayDT]

I’ll take the 18z NAM please and thanks...

[Haris]

I’ll take the 18z NAM please and thanks...

Not so fast, let’s take that snow shield and extend it down to Austin and all is well

[TheProfessor]

This whole time I've been worried about missing a potential storm in Ohio(which has backed off now) When I should be worried about my flight being canceled on Friday because of snow in Dallas.

[Ntxw]

Yep I think you're right..... with almost zero sub-freezing surface air to tap into, this is going to take negative high 4's to low 5's standard deviations at the 500Mb level to produce snow down to surface

This is the kind of stuff we have been raving for though with the right Nino and low solar. These are potent ULL and eventually with climo, they will all try to snow as it gets closer deeper into the season.

This system coming through later this week really doesn’t even have any cold air to work with. It’s basically just sucking in all the cold air around it, into it, which isn’t much. Even saying all that, there still looks to be a chance of snow up there for you guys. Wait till we get some true cold air to work with and much more of the state could be in for something.

This is what made years like 2009-2010 and late 2014-2015 great. None of the systems were really cold and frigid. In fact the times that it was lowest temp in those seasons it was dry. Largely we look for these strong ULL's to bring surprise snows. Tis the right season for that kind of stuff. With climo working for us until late Feb, marginal becomes good.

[bubba hotep]

With surface temps near freezing, That's a Hammer!



ETA: Winds would be kicking during that.

[TheProfessor]

That's a very impressive deformation band on the NAM, could easily see 4-8" fall in something like that.

[bubba hotep]

The 12z Euro Control run dumps nearly a foot just SW of Dallas. Nearly 75% of the members show this system producing some variation of a winter wx solution. This will be a very difficult forecast for FWD unless things trend safely into the no snow zone.

[Texas Snow]

Outstanding AFD by FWD

.LONG TERM...
/Tuesday Night into Early Next Week/

The main focus for the long-term period is the potential for a
very dynamic, impactful storm system during the latter half of
this week, especially Thursday into early Friday. This system has
the possibility to be multi-faceted in terms of impacts, but there
is considerable uncertainty with regard to the evolution of the
system and the resultant impacts to North and Central Texas.
Regardless, we are closely monitoring the potential for the
following:

1) Strong winds (anywhere from a west-northwest to a northerly
direction) Thursday into early Friday across much of the region
(medium-high confidence).

2) Any potential for snowfall late Thursday into early Friday
primarily across the western half of North Texas (low confidence).

3) The potential for strong storms Thursday towards East Texas
(low confidence).

Now for the details:

The evolution of the mid/upper pattern, and its impact on
pertinent surface features (and sensible weather), will rely on
the complex interplay of at least two shortwave troughs
approaching the southern Plains through mid/late week. Initially,
in the wake of a low-amplitude 500mb ridge sliding east, return
flow across Texas will transport 40s/50s dew points, increasing
temperatures, and some pockets of low-level stratus northward
across our area Wednesday.

While our local weather should be relatively quiescent through
Wednesday night, the aforementioned shortwave impulses upstream
should begin to interact to set the stage for at least some
impactful weather across North and Central Texas starting on
Thursday.

Medium-range guidance is in relatively good agreement on the
general idea that a strong 120+ kt north/northwesterly upper jet
will allow a sharp shortwave trough to dig south/southeast across
the southern High Plains and generally towards the Red River
Valley into the day Thursday. Meanwhile, a secondary, weaker
southern-stream impulse is expected to lift east/northeast across
Texas through early Thursday. This initial impulse and related
warm-advection to its east is expected to generate at least a few
shallow showers during the morning hours, generally along/east of
the I-35 corridor.

/*Strong Storm Potential*/
While likely the lowest potential impact, any strong storms would
be the first of the three facets mentioned above to affect our
region. Strengthening kinematic profiles (characterized by
southerly surface winds veering to robust west/southwest mid-level
flow) would offer a conditional environment favorable for
organization of deeper, sustained updrafts. However, there are
several negative influences on strong/severe weather potential: 1)
Passage of the initial wave Thursday morning likely veering low-
level flow some (reducing convergence), 2) only modest levels of
return moisture, and 3) the possibility of a relatively early
passage of a dryline/front that would minimize time for any
destabilization, especially given expected cloud cover early
within the warm conveyor. In turn, any potential will likely be
confined towards Paris/Sulphur Springs/Palestine through the
morning/afternoon, and surface-based buoyancy appears limited even
this far east. Still, there could be some potential for a few
stronger convective gusts in any thunderstorms, and we`ll continue
to monitor the possibility that a slower progression of the
referenced surface/mid-level features could slightly boost
chances for a few stronger storms across East Texas.

/*Strong Wind Potential*/
The second issue with which to contend is the strengthening winds
which will be spreading east/southeast across North/Central Texas
through Thursday night. As the secondary, very energetic impulse
approaches the region, focused ascent along its leading edge
should bring a surface cyclone southeastward across parts of the
southern Plains on Thursday.

Where these features track will notably impact the wind direction
and max gust potential. Using the surface low as a simplified
proxy for the entire system, a more northerly/easterly track
(generally along/north of the Red River to the Arklatex) would
bring strong westerly winds behind the initial dryline/front during
the day, followed by strong north/northwesterly flow behind the
main cold front later in the day. This track would also place most
of our area under steeper low-level lapse rates, enhancing gust
potential. In fact, the upper-end of the gust potential could be
near 50 kt, based on some forecast thermal/kinematic profiles. A
more southerly/westerly track (generally south of I-20) would
confine steeper low-level lapse rates, a higher gust factor, and
the strongest overall flow more west of I-35 and south of I-20.
These are spatial details that are simply too difficult to assess
with much certainty around 60-72 hours in advance so will continue
to advertise strengthening northwesterly flow on Thursday
(especially towards western North Texas and Central Texas), with
gusts up to 35-40 kt. Either way, some impacts from windy
conditions are likely to be realized. Start planning to secure
loose decorations and other items before Thursday!

/*Wintry Weather Potential*/
The last, and most attention-grabbing (per usual), forecast factor
is the possibility of snow late Thursday into early Friday across
parts of the region. As the mid/upper low digs southeast across
the southern Plains on Thursday, an amplifying 700-500mb
frontogenetic circulation (aided by deformation processes) is
forecast to establish somewhere from portions of West Texas
eastward to the Sabine Valley late Thursday. Fairly robust mid-
level ascent associated with this band will likely produce a
generally north-south oriented corridor of at least moderate
stratiform precipitation that could develop east across parts of
Central/North Texas through Thursday night.

With regards to the low-level thermal profile, if you`re a snow
lover, the northern stream is doing no favor. The reason is that
any lead impulses across the central US will generally be of
Pacific origin, with a resultant lack of very cold surface air
over the Plains. Therefore, as any frontogenetic band shifts
across the region, surface temperatures are generally expected to
be in the upper 30s/lower 40s Thursday night. Despite notably
cooling temperatures aloft within the 850-700mb cold conveyor
trailing the mid-level low, the lowest several thousand feet
should be above freezing through the night. Therefore, will
maintain only rain in the forecast at this time.

The largest caveat is that vertical motion in the mid levels may
be fairly robust within this potential comma-head band. If and
where precipitation rates are heavy enough, diabatic effects
(i.e., melting snow locally cooling the environment) may be
sufficient to bring snow to the surface. Medium-range guidance is
hinting at this potential by showing a small "blob" of mid 30s
surface temperatures underneath the modeled deformation band,
which the GFS/ECMWF both shift across parts of North Texas through
Thursday night. It is certainly plausible that some snow could be
found embedded within this band. However, due to the noted
concerns from a lack of antecedent cold air, it will likely
require moderate/heavy precipitation rates to locally cool the
environment enough for surface snow. As mentioned, some guidance
indeed shows this potential over parts of our area, but a look at
ensemble guidance shows the sensitivity of surface precipitation
type to when/where the mid-level system closes off/deepens, as
this will be where precipitation rates would be high enough to
overcome remaining low-level warm air.

With all of that said, this would likely be a focused area, and a
wide range of solutions is plausible with this event. Indeed, the
15Z SREF shows only one outlier solution with appreciable
accumulating snowfall across North Texas. So it`s certainly not an
easy forecast, but the current set-up generally warrants
continuing only a liquid forecast. Still, there exists a very low,
but non-negligible, potential for a locally impactful event late
Thursday into the overnight. Continue to check back with us, local
media, and other trusted weather sources for the latest.

After this system, a progressive pattern persists across the
southern US, with a warming/drying trend into the upcoming
weekend. Thereafter, precipitation chances look to increase
slightly during the first half of next week, as another southern
stream system approaches.

Picca

[Cerlin]

It’s not often you see the Euro, GFS, and NAM agreeing on something wintry this close...DFW might win on this one but I’ll knock on wood just in case!

[Ntxw]

Rain or snow, don't forget the system is very deep. Tight gradient will yield 20-30mph+ of winds. Quite a potent system. Heights wise, it may be in the ballpark of Christmas Eve 2009.

[Brent]

This is.so weird its not a week out like usual

[weatherdude1108]

Bob Rose:

Monday, December 10, 2018 3:01 PM

It was a cold weekend across Central and South Texas in the wake of Friday's heavy rain. Temperatures held in the 40s Saturday and only warmed to the mid-50s Sunday. As we kick off the new week, a large dome of cool, Canadian high pressure covers Texas and the southern Plains states. This high will remain over the region into Tuesday, causing continued cool temperatures. Milder readings are forecast Wednesday and Thursday as southerly winds return to the region.

Weather conditions will be sunny and dry today and Tuesday. The temperature should warm to the mid and upper 50s this afternoon and to the low and middle 60s Tuesday. Another freeze is forecast for the Hill Country Monday night into Tuesday morning. Lows Tuesday morning will be around 28-32 degrees across the Hill Country, in the middle 30s across Central Texas and in the upper 30s across the coastal plains. Lows Wednesday morning will be in the upper 40s.

The sky is predicted to become mostly cloudy Tuesday night through Wednesday as clouds and moisture increase off the Gulf of Mexico. Forecast solutions call for a weak wave of low pressure to track northeast out of Mexico and move across the state Wednesday. Atmospheric moisture levels may increase sufficiently to cause the development of a few spotty light rain showers for areas east of Interstate 35 Wednesday and Wednesday night. Wednesday's temperature is forecast to warm to the mid and upper 60s. Expect a southerly breeze at 10-15 mph. The low Thursday morning will be around 50 degrees.

Forecast solutions call for a stronger trough of low pressure to dip south out of the southern Rockies and move east across the Red River Valley region Thursday and Thursday night. In advance of the trough and its associated cold front, there will be a slight chance for a few rain showers for areas along and east of Interstate 35 Thursday and Thursday evening. The probability for rain will be near 20 percent. Should rain showers develop, amounts are predicted to total less than a quarter inch. Thursday's sky will be partly to mostly cloudy. The temperature is forecast to warm to the low 60s ahead of the front, trending down through the 50s in the afternoon.

The big weather story for Thursday into Friday will be strong and gusty northerly winds developing behind the cold front. Forecast solutions indicate a strong low-level northerly jet will influence winds at the surface. Forecasts call for northerly winds of 20-30 mph with gusts to around 40 mph developing Thursday afternoon, with the strong winds persisting Thursday night and Friday. Lows Friday morning will include the mid-30s across the Hill Country, the upper 30s across Central Texas and the lower 40s towards the coast.

A sunny, dry and somewhat mild weather pattern is predicted Friday through next Monday as a weak ridge of high pressure in the upper atmosphere settles over the region. High temperatures in the upper 50s Friday, will warm to the low 60s Saturday and the middle 60s Sunday and Monday. Low temperatures Saturday morning will generally be in the mid-30s, warming to the mid-40s over the weekend.

The outlook for next week calls for a chance for rain showers developing Tuesday, continuing through Thursday or Friday as a trough of low pressure from the Pacific pushes inland over northwestern Mexico and slowly tracks to the east. This system is forecast to bring scattered to numerous rain showers to the Central and South Texas. Temperatures next week are predicted to remain mild, with highs in the 60s and lows in the 40s to around 50 degrees.

It's still too early to get a handle on weather conditions around Christmas Day. However, long-range forecast data doesn't show a pattern that is favorable for arctic air to spill into Texas over the next couple of weeks. I'll begin to get a better idea about holiday weather over the coming week.

Thursday and Friday Rainfall Totals

Friday's slow-moving storm system brought widespread, soaking rains to all of Central and South Texas. Amounts were highest for areas east of Interstate 35, where totals generally averaged between 3 and 4 inches. Totals across the eastern Hill Country and the Interstate 35 corridor were generally between 2 and 3 inches. Rain amounts were lowest across the western Hill Country where totals were mostly between 1 and 1.5 inches. LCRA's highest gauged storm total was 5.13 inches at a gauge in northwestern Bastrop County, along Wilbarger Creek. A gauge in northwestern Matagorda County, near Midfield, recorded 5.09 inches.

The following is the National Weather Service's estimate of rain falling between 6 am Thursday and 6 am Monday:



https://www.lcra.org/water/river-and-we ... ather.aspx