February 2021: Arctic Outbreak/Warmup Begins

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jasons2k
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Re: February 2021: Arctic Outbreak/Warmup Begins

Post by jasons2k » Tue Feb 23, 2021 2:04 pm

txbear wrote:
Tue Feb 23, 2021 10:39 am
I really think that had energy generation not been an issue (not starting political talk here; just pointing at that piece of the puzzle), we would probably be having a much different talk about the super chill of last week. Not to say that the warm weather lovers wouldn't still be happy with the current weather ;)

Heck, I'm a cold weather cheerleader, and didn't even allow for real enjoyment of the snow because the power was out and no real way to warm up; much less the in-and-out of the house letting more cold air in. There would still be some pipe bursts and the tropicals would be torched, but much more would be avoidable because water pressures would've stayed up and warmth would still be directed to sensitive areas of homes. I believe everyone is going to have a cost of the freeze, but I really feel for those that suffered the worst of the worst.

ETA: I have my share of pipe repairs and landscaping to complete as well; we were certainly not unscathed here.
Totally agree - the massive grid failure made things a lot worse than it should have been. But that's the thing with these extreme events. We are playing with fire. The power grid statewide could have stayed-up but the ice storm could have been much, MUCH worse than it was, and a lot of us (locally) would still be without power had we gotten 1/2" + of ice.

It almost happened, too.

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Re: February 2021: Arctic Outbreak/Warmup Begins

Post by tireman4 » Wed Feb 24, 2021 7:32 am

000
FXUS64 KHGX 241159
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
559 AM CST Wed Feb 24 2021

.AVIATION...

Low level moisture continues to stream into the area beneath a
stout capping inversion around 850 mb. A mix of VFR/MVFR and
possibly IFR ceilings are expected this morning into the early
afternoon. Ceilings should begin to mix out during the afternoon
with VFR conds most TAF sites into the early evening. Could be a
few showers or spotty drizzle but probability of occurrence looks
too spotty to mention in the TAFs. A cold front will move into the
area tonight with VFR ceilings becoming MVFR after 06z. The front
should stall over the central zones and could produce some showers
near the Houston terminals. As for KGLS, conditions look very
favorable for sea fog tonight. Have dropped vsby and cigs for this
TAF site, however confidence is low on both timing and intensity
of fog. 43

&&

.PREV DISCUSSION... /ISSUED 410 AM CST Wed Feb 24 2021/

SHORT TERM [Today Through Thursday Night]...

Onshore winds will persist today and this will allow low level
moisture to build beneath a strong capping inversion. This WAA
pattern will allow for some weak showers or spotty drizzle from time
to time. 850 mb temperatures remain very warm so MaxT values will
again be very warm. Shaved a few degrees from yesterdays values due
to expected cloud cover but MaxT values should reach the mid 70`s.

Moisture deepens further tonight and PW values reach 1.20 inches.
The saturated layer grows to a depth from the surface to around 800
mb. A weak cold front will also enter SE TX and the combination of
deeper moisture coupled with convergence along the front should
yield some showers tonight. The front is expected to stall over the
central zones tonight so went with slightly higher rain chances over
the central zones due to better low level convergence. MinT values
will be tricky as the location of the front will dictate the amount
of cooling behind the front. NAM is the coldest of the models and
looking upstream, it looks a bit colder than current obs so used a
MET/MAV blend with MinT values in the lower 50`s north and lower
60`s south/coast.

Warm and moist air flowing over the cooler shelf waters will produce
periods of sea fog tonight near the coast. Will continue to mention
sea fog in the wx grids tonight and Thursday. A weak area of low
pressure will move along the stalled frontal boundary on Thursday.
PW values will hover around 1.20 inches. The additional lift from
the weak low, the stalled front and some increasingly favorable jet
dynamics should give the area a good chance of rain. The higher rain
chances will be over the northern zones, north of the sfc low and
closest to the jet dynamics. 43

LONG TERM [Friday Through Wednesday]...

Through the day on Friday, the weak cold front is expected to move
back towards the north. The speed of this northward trajectory
will have an impact on MaxT values, especially for our northern
counties. For now, leaned towards low 60s in the far north
locations to indicate the front not pushing out of the CWA until
after peak heating. 70s will be in place further south as onshore
flow will prevail through the weekend. This also means that the
sea fog threat will likely last into early next week. Steady
onshore flow will keep PWATs above 1.25" through at least Tuesday
with a couple of peaks over 1.5" on Sunday and Monday. Instability
will be on the rise as well with CAPE values of 800-1000 J/kg and
LI values around -4 in the northern half of the CWA by Saturday
afternoon. With favorable jet dynamics in place as well, the
environment seems primed for thunderstorm development through
Monday.

There is consensus from the GFS, ECMWF, and Canadian models that a
shortwave trough will drift down from the Four Corners region.
Still a bit of uncertainty on how far south it extends. Kept in
higher PoPs for our northern counties since PVA looks likely
enough to lift the moisture still in place closer to the
surface. After Monday is when the models diverge. The ECMWF and
Canadian models push a cold front through the region on Monday
night/Tuesday morning and removes the rain and sea fog, then a
second front on Wednesday morning with high pressure building in
behind it. The GFS has a cold front approach the region and lose
its steam as it moves southeastward. It does move off the coast by
Monday night, but since it is much weaker, winds remain more
easterly and allows the moisture to remain in place. This would
mean rain chances would linger through at least Tuesday. The high
pressure in the GFS pushes eastward more quickly as well which
would return rain chances by Wednesday night as moist, onshore
flow is reintroduced. Leaned more towards the GFS solution for now
and kept PoPs in throughout the day on Wednesday.

There is model consensus on dew points falling back into the low 50s
by Monday night/Tuesday morning, so this would mark the end of
the period of sea fog. Until then, once the sea fog develops, it
will continue to persist and bring low visibilities for coastal
locations especially in the overnight hours. 26

MARINE...

Onshore flow expected to persist through the weekend and into
early next week. The continuous warm air advection has been
steadily increasing dew points over the waters. Nearshore dew
points will reach the low 60s in the late morning/early afternoon
today while water temperatures are still in the 50s. As a result,
sea fog will develop and will likely last into early next week. A
weak cold front will approach the coast on Thursday, but model
guidance indicates that it will not be close enough to the coast
to dampen the impacts of the fog. The front will then push back to
the north on Friday allowing for the onshore flow to prevail and
subsequently the sea fog as well. 26

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 76 52 62 53 63 / 10 20 50 60 30
Houston (IAH) 78 59 70 57 71 / 20 30 40 40 30
Galveston (GLS) 69 61 68 59 65 / 20 30 40 30 20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

Discussion...99
Aviation/Marine...99

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Re: February 2021: Arctic Outbreak/Warmup Begins

Post by srainhoutx » Wed Feb 24, 2021 8:11 am

NWS Houston/Galveston issued their recap of the Historic Valentine Arctic Outbreak Freezing Rain/Sleet/Snow Storms for February 11th to February 20th...

https://www.weather.gov/hgx/2021ValentineStorm
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

Member: National Weather Association
Facebook.com/Weather Infinity
Twitter @WeatherInfinity

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Re: February 2021: Arctic Outbreak/Warmup Begins

Post by knightindustries2000 » Wed Feb 24, 2021 11:14 am

i just went outside to water my tomato bell pepper plants. It felt disgusting and humid. The air didnt feel comfortable at all.

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Re: February 2021: Arctic Outbreak/Warmup Begins

Post by Cpv17 » Wed Feb 24, 2021 5:17 pm

Very boring stretch of weather coming up. We need that to recover though.

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Re: February 2021: Arctic Outbreak/Warmup Begins

Post by Cromagnum » Thu Feb 25, 2021 8:48 am

What are thoughts on spring severe weather season this year?

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Re: February 2021: Arctic Outbreak/Warmup Begins

Post by tireman4 » Thu Feb 25, 2021 10:39 am

000
FXUS64 KHGX 251152
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
552 AM CST Thu Feb 25 2021

.AVIATION...

Guidance is very pessimistic with regards to ceilings and
visibility today and tonight but surface observations seem to tell
a slightly different story. ConShort and NBM sky grids show
ceilings below 800 feet for most of the day, while NAM and GFS
fcst soundings show MVFR ceilings transitioning to IFR tonight.
Surface observation have been trending from IFR to MVFR and now
VFR cigs. With moisture continuing to stream into the region under
a strong cap at 5000 feet, think there could be sufficient mixing
in this layer to allow for VFR ceilings before the inversion
lowers late in the day. Showers will stay mainly north of the
Houston terminals today with a slightly higher chance for precip
tonight as a weak cold front approaches. Intermittent periods of
sea fog will affect KGLS all day and again tonight. A mix of
IFR/MVFR and VFR ceilings will affect KGLS. 43

&&

.PREV DISCUSSION... /ISSUED 455 AM CST Thu Feb 25 2021/

SHORT TERM [Today Through Friday Night]...

A weak cold front has moved into SE TX and this boundary will serve
as a focus for showers today. At 3 AM, the front is along a Brenham
to Huntsville to Crockett line. The front will continue to sag south
and should make it around the I-69 corridor before stalling out.
Drier air has worked into the area behind the front but temperatures
have been slow to cool. This makes today`s temperature forecast a
bit of a challenge. The NAM looks to have a good handle on the
frontal movement but it still looks too cool with temperatures so
have leaned toward a MET/MAV/NBM blend. Models have also been
aggressive with high PoPs today (and last night) and precip has also
been slow to develop. PW values today are between 1.20 and 1.45
inches and the moist layer extends to around 800 mb with strong
capping in the 850-700 layer and a lot of dry air above the
inversion. Considering the moisture levels and the convergence along
the front, feel the potential is there for showers and will continue
with Chance PoPs for today. Sea fog has been affecting the coast
since last evening, but visibility has recently improved. Conditions
are favorable for dense fog as dew points in the upper 50s move over
water temps in the lower 50`s. Will maintain the NPW for dense fog
as the potential for additional sea fog remains high.

For tonight, the location of the front will directly impact MinT
values. NAM is once again the coldest of the models and again
blended the much colder NAM with the NBM and MAV guidance. The weak
boundary may actually retreat north a bit as weak low pressure
develops over Central TX and moves east and this feature should tug
the front back to the north a bit. Highest rain chances tonight
should be to the north of the sfc low and retreating boundary. There
looks like there is enough instability north of the front to
generate a few thunderstorms and have added isolated thunder to the
wx grids. South of the front, PW values lower to around 1.20 inches
with very dry air noted int he 850-500 mb layer. Will still carry
low PoPs over the south but most areas will likely remain dry.

Once the weak sfc low moving along the front pushes east of the
region another weak reinforcing boundary pushes into SE TX. This
makes the temperature forecast for Friday tenuous. Have once again
leaned toward blending the much cooler NAM with the MAV/NBM
guidance. The College Station area could remain in the lower 60`s
while the Houston area basks in the upper 70`s. The frontal location
will have a huge impact on MaxT values. PW values lower to around an
inch on Friday but with a weak boundary draped over the region, feel
there may be enough low level convergence to support a few showers.
Sea fog will remain a constant near the coast and Galveston should
expect intermittent periods of sea fog Friday and likely through
the weekend. 43

LONG TERM [Saturday Through Thursday]...

With onshore flow continuing to persist, PWAT values will steadily
rise and reach a peak near 1.50" by Saturday afternoon. Favorable
jet mechanics will be place for the northern half of the CWA along
with plenty of instability as CAPE values will range from 800-1000
J/kg and LI values from -4 to -2. LLJ develops over the northern
CWA going into Saturday night, so the environment will be suitable
for thunderstorms through at least Monday. With the persistent
onshore flow lasting through Monday, expecting temperatures to
remain rather mild with highs in the 70s and lows in the 50s/60s.
This is also indicative of the sea fog sticking around into early
next week as well.

Another cold front approaches the region on Monday morning, but
there are diverging ideas between the models on what occurs
following FROPA. Firstly, there is consensus on this front making
it off of the coast. PoPs are higher for Sunday night/Monday
since we will have low-level convergence along the frontal
boundary with PWAT values ranging from 1.50-1.75" still in the
area. Dew points will drop back into the 50s by Monday night and
should mark the end of this period of sea fog. Now let`s get to
the model differences. GFS/Canadian push the front off the coast
and have high pressure building in behind it for CAA lasting into
Wednesday. The ECMWF does much of the same but pushes the high
pressure eastward faster. This would bring warm, moist air back
for Wednesday, so this has a pretty big impact on temperatures and
rain chances. Added in low PoPs for Wednesday to account for
this. If water temperatures remain relatively cool, this would
also mean a return of the sea fog as well.

Thursday presents another major difference in the models as
the ECMWF/Canadian indicate lee cyclogenesis off the Rockies and
a strong cold front pushing through the area by Thursday morning
along with a pretty sizable positively-tilted shortwave. The GFS
also shows lee cyclogenesis, but it has a slower progression.
Still too far out to put a lot of weight into throwing in
significantly cooler temperatures, but have added PoPs in for
Thursday since rain looks likely along the frontal boundary. With
an unfavorable tilt in the shortwave trough and low instability,
not expecting thunderstorms for now. 26

MARINE...

Sea fog has developed in the Bays and nearshore waters and is
expected to persist throughout the day. The Dense Fog Advisory will
likely need to extended since the onshore flow will remain in place
with dew points holding steady in the low 60s. A weak cold front
will drift towards the coast but will stall inland later in the day.
There is a possibility that the front may extend far south enough to
give a brief break to the fog for portions of the Bays. The front
will then push back to the north by Friday morning, so it would be a
short-lived break at best. Onshore flow continues to persist into
Monday night when another cold front is expected to push off the
coast. The timing of this frontal passage differs from model to
model, but there is consensus on it pushing off the coast and ending
the period of sea fog. 26

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 64 51 63 58 75 / 50 70 40 20 50
Houston (IAH) 73 64 75 63 75 / 40 40 30 20 30
Galveston (GLS) 66 60 68 61 67 / 30 30 20 20 20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Dense Fog Advisory until 9 AM CST this morning for the following
zones: Chambers...Coastal Galveston...Coastal Harris...
Galveston Island and Bolivar Peninsula.

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

&&

$$

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Re: February 2021: Arctic Outbreak/Warmup Begins

Post by txbear » Thu Feb 25, 2021 12:39 pm

What are y'alls thoughts on any additional freezes at least through mid-March? Wanting to get started with the landscaping clean up, but need to be mindful of any additional possible freezes. Looking at the CPC, it looks like we're in a patter of above normal temps for the next 8-14 days+. I'm starting to feel like we're probably good to go, but a bit hesitant since I want to avoid damage on top of what has already been torched.

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Re: February 2021: Arctic Outbreak/Warmup Begins

Post by jasons2k » Fri Feb 26, 2021 9:57 am

txbear wrote:
Thu Feb 25, 2021 12:39 pm
What are y'alls thoughts on any additional freezes at least through mid-March? Wanting to get started with the landscaping clean up, but need to be mindful of any additional possible freezes. Looking at the CPC, it looks like we're in a patter of above normal temps for the next 8-14 days+. I'm starting to feel like we're probably good to go, but a bit hesitant since I want to avoid damage on top of what has already been torched.
I would hold off. Warmer weather is in place for now but this pattern lends itself to late season cold shots. Could see another blocking setup that would send us another one. Not like last time, but enough for a freeze risk. I would wait to see how things evolve over the next couple of weeks.

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Re: February 2021: Arctic Outbreak/Warmup Begins

Post by DoctorMu » Fri Feb 26, 2021 12:34 pm

jasons2k wrote:
Tue Feb 23, 2021 2:04 pm
txbear wrote:
Tue Feb 23, 2021 10:39 am
I really think that had energy generation not been an issue (not starting political talk here; just pointing at that piece of the puzzle), we would probably be having a much different talk about the super chill of last week. Not to say that the warm weather lovers wouldn't still be happy with the current weather ;)

Heck, I'm a cold weather cheerleader, and didn't even allow for real enjoyment of the snow because the power was out and no real way to warm up; much less the in-and-out of the house letting more cold air in. There would still be some pipe bursts and the tropicals would be torched, but much more would be avoidable because water pressures would've stayed up and warmth would still be directed to sensitive areas of homes. I believe everyone is going to have a cost of the freeze, but I really feel for those that suffered the worst of the worst.

ETA: I have my share of pipe repairs and landscaping to complete as well; we were certainly not unscathed here.
Totally agree - the massive grid failure made things a lot worse than it should have been. But that's the thing with these extreme events. We are playing with fire. The power grid statewide could have stayed-up but the ice storm could have been much, MUCH worse than it was, and a lot of us (locally) would still be without power had we gotten 1/2" + of ice.

It almost happened, too.
Arkansas had no trouble handling worse weather. Arkansas. ERCOT got caught with their pants down - they should have been online with us! ;) They didn't winterize. They had too many gas and coal power plants offline. Can't do that with an isolated grid. Incompetence is not a free market in a virtual monopoly (I have only 1 choice for power and natural gas). I'll pass my power and gas bills along to our state executive and legislative branches and ERCOT...

But yeah, if the ice had been worse...then we'd see ice storms every year in NC and the power grid didn't collapse.

Misty and mild looks like it's the outlook for the next few days. Anything to avoid using heat or A/C for awhile!

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