February 2021: Arctic Outbreak/Warmup Begins

[Andrew]

What are the Euro control and ensembles showing in terms of frozen precip next week?

This is the snow map:

[txsnowmaker]

What are the Euro control and ensembles showing in terms of frozen precip next week?

This is the snow map:

Isn’t that just the operational though?

[DoctorMu]

Yeah, the Euro right now is similar to the Jan 10 snow event up here in the NW territories.

https://weather.us/model-charts/euro/te ... 0600z.html

Except there's a lot of freezing rain/sleet around Houston.

[Andrew]

What are the Euro control and ensembles showing in terms of frozen precip next week?

This is the snow map:

Isn’t that just the operational though?

Ensembles won't be out for another couple of hours.

[Stratton20]

https://images.weatherbell.com/model/ec ... JB4NXM.png

Here is the 00z ensemble snowfall run

[Stormlover2020]

Yeah, the Euro right now is similar to the Jan 10 snow event up here in the NW territories.

https://weather.us/model-charts/euro/te ... 0600z.html

Except there's a lot of freezing rain/sleet around Houston.

It’s not similar stop saying that

[Kingwood36]

Euro LOVES that 105....I dont see how the icon,cmc,ukmet,gfs,all have a winter storm for here and frozen precip but the euro is the only one who doesn't have it and keeps everything rain till you get to the Brazosvalley...im not buying the euro

[Andrew]

Somehow the GFS is even colder on the 06Z run. Incredible

[TexasBreeze]

Didn't expect 2 degrees coming on the model....

[MontgomeryCoWx]

It’s a blend of 1989 and 1899.
Truly wild.

I’m used to this cold from my time at Ohio State and in Montana, but it’s different for sure

[srainhoutx]

Wednesday morning weather briefing from Jeff:

A significant outbreak of arctic air is increasingly likely this weekend into next week.

Potential for a winter storm late weekend into early next week

Today-Thursday:

Surface frontal boundary has been stalled along US 59 for much of the night with temperatures NW of this boundary in the 40/50’s and SE of the boundary in the 60’s. Dense sea fog has spread inland south of the front and recently a few showers have begun to develop along and north of the boundary. This front will remain nearly stationary for much of the day along US 59 and then begin moving southward tonight. A strong upper level disturbance will approach the region tonight into Thursday and pull moisture up and over the surface cold dome resulting in widespread showers and some thunderstorms on Thursday. Most of the rainfall today will be showers, drizzle, and light rain and that will become more widespread and increase in intensity Thursday and Thursday night. Temperatures will fall on Thursday into the 50’s for the entire region with 40’s over the NW counties as the front moves offshore.

The upper level disturbance will move east of the area and Friday and a cold Canadian air mass will settle over the region with cold air advection ongoing. Expect all rainfall to end by Friday morning, but clouds may hang tough much of the day. Will go with lows in the upper 30’s and highs in the upper 40’s on Friday…but this is just a small taste of what is to come.

Weekend:

Impressive arctic high pressure dome over NW Canada surges southward down the US central plains with global forecast models showing 1040-1050mb arctic high centered over the Midwest by Sunday morning. Expect the arctic front to arrive in SE TX Saturday afternoon and already cool temperatures will fall. Strong cold air advection increases again Saturday night and will likely drive much of the area below freezing. This will likely be an advective freeze which tends to be highly damaging to sensitive plants as the concept of using the ground warmth with covering materials is reduced in strong surface wind situations. Highs on Sunday will struggle to reach 40 for much of the area and the entire area will fall below freezing Sunday evening and likely remain below freezing into midday Tuesday. Lows Monday morning will likely range in the 20’s for the entire area with wind chills in the teens…this is still warmer than some of the coldest guidance and some downward adjustments may be needed as the time period nears.

Winter Storm Potential:

Arctic air masses are notorious for their cold and potential for winter storms with some of our most memorable events of the past happening with the upper air setup of this weekend into next week. As the arctic cold dome becomes entrenched on Sunday, an upper level storm system will approach from the western US and move into TX Sunday night and Monday. This upper level system will induce surface low pressure over the lower TX coast that will bring moisture northward into the very cold air mass. Precipitation is increasingly possible Sunday night into Monday night. Forecast soundings indicate all precipitation types would be possible (freezing rain, sleet, and snow) at various times during the period as the shallow arctic air mass deepens over the area.

There is still a lot of uncertainty on how much moisture will be available, but there is increasing confidence in some sort of winter precipitation during this period

Preparation:

Residents should make cold weather preparations for an extended period of very cold weather (4 P’s) and this will have to include pipes for this event. Most events in this area are mild and short duration and do not effect pipes, but pipes will need to be protected for the intensity of the cold and long duration of sub-freezing conditions.

Monitor forecasts closely for updates over the next few days.

[jasons2k]

Key point for me:
This will likely be an advective freeze which tends to be highly damaging to sensitive plants as the concept of using the ground warmth with covering materials is reduced in strong surface wind situations.

I will probably bring the potted citrus, etc. into the garage. Not gonna be fun on Saturday.

[Cromagnum]

Wondering how best to try to protect my water softening system outside. Tarp with a warm light underneath?

[Cpv17]

Somehow the GFS is even colder on the 06Z run. Incredible

What are the wind chills at the same time?

[MontgomeryCoWx]

Somehow the GFS is even colder on the 06Z run. Incredible

What are the wind chills at the same time?

5 to 20 below depending on location

[srainhoutx]

Somehow the GFS is even colder on the 06Z run. Incredible

What are the wind chills at the same time?

[MontgomeryCoWx]

I would go for a nice run in that. I’ve done it before but it’s serene. Yep!

[txsnowmaker]

Umm... this is looking to be much more than a freezing rain/ice event for Houston if the latest GFS comes to pass. Around a foot and a half of snow for the city of Houston. Incredible.

https://www.tropicaltidbits.com/analysi ... _us_35.png

[Kingwood36]

Umm... this is looking to be much more than a freezing rain/ice event for Houston if the latest GFS comes to pass. Around a foot and a half of snow for the city of Houston. Incredible.

https://www.tropicaltidbits.com/analysi ... 21006&fh=6

I wouldnt believe that being this far out still..but it is nice to look at

[tireman4]

485
FXUS64 KHGX 101037
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
437 AM CST Wed Feb 10 2021

.SHORT TERM [Through Thursday Night]...

At 4am, a shallow cold front was situated from roughly Edna-Wharton-
Houston-Cleveland. It should remain in that general vicinity for
most of the day. Some guidance drifts it north a touch, others
(primarily the hires guidance that was heavily weighted) sags it a
bit further south. South of the boundary, dense sea fog has rolled
back in. Visibilities will again improve inland during the mid-late
morning hours, but not so much along the beaches and offshore.

Moist southerly flow just above the sfc will be transporting an axis
of higher PW`s into the region. Expect some sct pockets of -ra to
begin developing this morning near the boundary...eventually
increasing in coverage and becoming more showery further to the
north during the day. Can`t completely rule out an iso tstm, but
it`ll be the exception rather than the rule.

Somewhat of a break in precip is anticipated for most areas late in
the day, but anticipate some additional sct development across the
area later this evening...mainly near and just to the north of the
frontal boundary as it begins a southward push toward and off the
coast.

Heading into to Thurs, western trof will be making ewd progress
closer to the area. We should still have some respectable PW`s in
the 1.2-1.5" range in place the region. Increasing large scale lift
(and a series of impulses embedded in the swly flow aloft and
favorable jet position) should allow precip to increase in areal
coverage thru the day Thurs and Thurs night. May see some elevated
tstms mixed in...and also some periods of training moderate rains at
times Thurs night. In general, 0.75-1.75" of rain can be expected in
the Thur-Thurs night time period. Grounds should be able to handle
this without much of an issue considering it`ll be spread out over a
fairly long duration, but always need to keep an eye on the rain
rates for any very localized issues that may crop up in association
with any training. 47


.LONG TERM [Friday through Tuesday Night]...

Cold to frigid conditions along with a chance for mixed
precipitation are the main story in the long term forecast.

Other than perhaps some lingering showers across our far
east/coastal zones Friday morning, the day should be relatively
dry. At the surface, CAA continues to filter in drier and colder
air, leading to daytime temperatures from the mid 40s to mid 50s.
This is 10 to 20 degrees below normal/average. Overnight lows will
range in the 30s and low 40s. By Saturday morning, the next
shortwave embedded within the southwesterly flow will allow for
increasing lifting and saturation along the BL, especially across
our western counties. Forcing, on the the hand, diminishes/weakens
as the shortwave moves east/southeast. Therefore, have only light
precipitation chances.

The scenario turns a bit more interesting as we head into Sunday
and early next week. The synoptic pattern aloft will be dominated
by a shortwave trough across central/southeast TX, a Canadian low
wobbling between the Great Lakes and the International Border,
and a low developing over the Pacific Northwest. The evolution of
this upper low is the one we should continue to monitor over the
coming days. This upper low will quickly progress across the
southern Rockies/central TX by Sunday, moving across the forecast
area on Monday. The environment will be favorable for widespread
precipitation as the region will be situated in a favorable
region of the upper level jet, with increasing PVA and decent
southerly LLJ. Will continue to monitor this system as models also
hint for some mid-level frontogenesis; however, the layer above
still remains more stable. With that being said, an unsettled
start to the week is likely. The main question will be p-types.
Latest guidance indicates that surface temperatures will likely
drop to near freezing across our northern/western counties,
bringing a wintry mix and/or freezing rain throughout the day.
Precipitation should quickly taper off by Monday night as a
strong surface high builds in. Well, to make matters worse, breezy
northwesterly winds will be possible, causing wind chill values in
the teens and 20s possible.

Speaking of cold....Significantly cold conditions are expected
this weekend into next week, with record breaking cold forecast.
The strong and amplified Arctic high will dive southward across
the Plains and into our region. While confidence is increasing,
there is still uncertainty on how cold southeast TX will get.
Continued with a cold forecast and went close to the mean and/or
coldest solutions from Day 4 - 7. Even chilly or frigid conditions
will be possible Monday night into Tuesday. Have leaned towards
raw deterministic and ConsALL for lows during this time-frame to
produce temperatures in the teens and 20s.


Key Messages:

1) Big changes on the way! A prolonged stretch of cold and winter
weather will be possible late this week into next week with
temperatures well below average for this time of year.

2) Precipitation chances increase late Sunday into early next
week with a potential for a wintry mix. Confidence is moderate in
terms of a wet/unsettled pattern during this period; however,
uncertainty arises on the type of precipitation.

3) A prolonged period of very cold conditions will be possible.
Be prepared to take action and protect people, plants, and
properties (pipes). We encourage you to monitor the forecast over
the next days for the latest information and/or possible
headlines.

05


&&

.AVIATION [12Z TAF Issuance]...

Not anticipating a whole lot of change in regards to flying
conditions for the next 24+ hours with IFR to LIFR conditions
prevailing thru the period. See the short term discussion above
for the general reasoning/setup. 47

&&

.MARINE...

Periods of dense sea fog will persist into tonight and early
Thurs morning prior to a cold front pushing off the coast. The
front will usher in a prolonged stretch of cold, unsettled weather
that will persist deep into next week. SCA`s will probably be
required at times with moderate n/ne winds and elevated seas
expected into the middle parts of next week. May even see some
gale conditions late Sunday night and Monday as the next
disturbance moves into the area. 47



&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL) 46 39 45 37 47 / 60 40 70 70 10
Houston (IAH) 63 50 56 44 52 / 40 40 90 70 20
Galveston (GLS) 67 56 60 47 53 / 30 50 70 80 30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...Dense Fog Advisory until noon CST today for the following zones:
Brazoria Islands...Galveston Island and Bolivar
Peninsula...Matagorda Islands.

Dense Fog Advisory until 10 AM CST this morning for the
following zones: Chambers...Coastal Brazoria...Coastal
Galveston...Coastal Harris...Coastal Jackson...Coastal
Matagorda...Fort Bend...Inland Brazoria...Inland
Galveston...Inland Harris...Inland Jackson...Inland
Matagorda...Wharton.

GM...Dense Fog Advisory until noon CST today for the following zones:
Coastal waters from Freeport to Matagorda Ship Channel TX
out 20 NM...Galveston Bay...Matagorda Bay...Waters from
Freeport to Matagorda Ship Channel TX from 20 to 60 NM.

Dense Fog Advisory until 3 AM CST Thursday for the following
zones: Coastal waters from High Island to Freeport TX out
20 NM...Waters from High Island to Freeport TX from 20 to
60 NM.


&&

$$

SHORT TERM...47
LONG TERM...05
AVIATION...47
MARINE...47