Monday, February 5, 2018

Feb. 4 18

Kingwood, TX, during the late morning.
Kingwood, TX, during the early afternoon.
New Caney, TX, I think, during the early afternoon.
North Houston, TX, during the early afternoon.
Northwest Houston, TX, during the early afternoon.
Northwest Houston, TX, during the early evening.


Locations: Northwest, north, and west Houston, TX, Kingwood, TX, Porter, TX, and New Caney, TX.


Thoughts: The sky stayed cloudy to maybe sometimes mostly cloudy with cool temps during the morning, evening, and night. It was warm during the afternoon. It looked like it wanted to rain, but it didn't. I don't think any of the locations in the Houston, TX area got any rain. I don't remember seeing, feeling, or hearing any rain drops.


Area Forecast Discussion 
Issued by NWS Houston/Galveston, TX
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000
FXUS64 KHGX 050417
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1017 PM CST Sun Feb 4 2018

.UPDATE...
Drier and cooler air filtering in from the northeast behind a weak
afternoon boundary passage. Despite this...clear skies have allowed
dew point depressions to fall below 3 degrees and dense fog has
developed over the northeastern CWA. Have issued a short fuse
Dense Fog Advisory to alert any travelers of sub mile visibilites
around Sam Houston-Davy Crockett NF/Lake Livingston area. The
drier and cooler air mass upon northeasterlies will aid in
saturating the lower couple of thousand feet below the frontal
inversion and either allow fog or low stratus to form or remain
through sunrise. A reinforcing cool northeast wind with a more
warm and moist southwesterly mid to upper flow will keep overcast
skies around through Monday. This will impact afternoon temperatures
with maxTs likely struggling to reach 60 F. Today`s boundary
becoming stationary offshore...along with PVA riding on through
within the (south)westerlies...will keep slight Gulf/coastal
chances in play for either Monday drizzle or light rain. Patchy
fog chances will still linger over the local bays and nearshore
waters through mid week. 31

&&

.PREV DISCUSSION... /ISSUED 542 PM CST Sun Feb 4 2018/

AVIATION...
Challenging aviation forecast tonight. Drier air is trying to work
it`s way in from the northeast, but moisture trapped under the
inversion may keep 800-2500ft ceilings in overnight - at least
that`s what is advertised in the 00z TAFs. Wouldn`t be overly
surprised to see CLL/UTS see a brief scattering of the clouds,
but all indications are that`ll eventually fill back in. MVFR
ceilings are expected throughout the day Monday...transitioning to
IFR during the late afternoon from south to north as winds veer
to the east and eventually southeast allowing for increasing Gulf
moisture to return inland. 47

PREV DISCUSSION... /ISSUED 355 PM CST Sun Feb 4 2018/
A fairly active period ahead, as a weak boundary is making its
way slowly today to make for a cool Monday. Then a very brief
warmup Tuesday, along with chances of rain and storms increasing
ahead of the next front Wednesday. The temperature rollercoaster
continues for the second half of the week - brief cooling behind
the front, then slow warming until the next front at the end of
the week brings more rain and storm potential to the area. This
active pattern should keep things from getting too out of hand,
we`ll have to keep a wary eye on both frontal passages. Though the
models - taken explicitly - don`t show a ton of potential,
relatively small errors could give us a setup with a shot at some
severe weather in the midweek front, and heavier rain with the
weekend front. Because of that, it would be wise to keep on top of
the forecast this week to stay ahead of any emergent threats with
these fronts.

NEAR TERM [Through Tonight]...
While it`s somewhat muddied in the obs, only shown really well by
a subtle wind shift and change in dewpoints, satellite makes it
abundantly clear where a weak front is on the northern edge of our
area as we sharply transition from the low overcast over our
corner of Southeast Texas to brilliantly blue skies on the other
side of the front. Because of that, it`s really, really hard to
justify calling this a cold front because the sunny skies have
allowed temperatures to rise higher than they are here on the
"warm side". Because of that, the boundary has become nearly
stationary, only dragging south as drier air filters in, mixes,
and erodes the low clouds.

Anyway, as the sun goes down and we see the reverse, with the
clearer skies cooling off faster, we should see a more significant
push of the front to the south, ushering in cooler, drier air and
offshore winds. It probably won`t be a very significant
difference, perhaps only enough to briefly end sea fog in the
waters for a bit as we approach dawn. Also, lows overnight should
be at least modestly cooler, with greater impacts well north of
Houston, and lesser cooling near the coast.

SHORT TERM [Monday Through Tuesday Night]...
Our period of offshore flow should be brief, with winds turning
back to be more easterly tomorrow and even southeasterly Monday
night. This will bring an influx of moisture right back in, and
the return of sea fog on Monday or Monday night, which may manage
to push onshore into some coastal areas. While there`s pretty
strong certainty in the return of sea fog, if the push will be
powerful enough to shove on land is a little more of an open
question. Despite that, we should at least look for a bit of
warming, with Monday night lows up, and Tuesday highs in the upper
60s to low 70s. Some spots near the coast southwest of Houston
may make a run for the middle 70s, even. However, with moisture
and onshore flow comes the return of rain chances - probably
fairly low Monday night, but increasing for Tuesday.

Tuesday afternoon, indeed, could be somewhat interesting. Pretty
solid agreement for at least some modest instability, and both the
GFS and Euro (amazingly out CAPEing the NAM) build 1000-15000 j/kg
of CAPE southwest of Houston, and turning in the low level winds
suggests a good bit of low shear and helicity. However, this
potential instability may remain just that - potential. The low
level jet looks to be fairly veered, which generally induces some
capping, the front is far to the north yet, reducing low level
convergence, and the upper jet is also far to our north, which
won`t help support upward motion, either. Something to keep an
eye on, but will need some changes in the atmosphere aloft to
really allow for much severe potential.

LONG TERM [Wednesday Through Sunday]...
Wednesday may be interesting, as well. the GFS is a bit slow with
the front, making it late enough for modest instability to build
again when the front rolls through, and could make for some
fireworks on the front. The NAM and Euro - and our forecast - show
a bit of a different scenario - quick with the surface front, but
lagging with the 850 front - this would allow for elevated CAPE
to emerge as warm air advection continues just aloft, and we could
see some elevated action behind the surface front. The
disconnection from the surface would limit the threat from severe
winds and tornadoes, but with enough elevated convection and
strong deep shear, we could see a shot for some hail in the
strongest storms. Because this scenario remains a bit iffy, we
concur with SPC in holding back on hitting this potential too
hard, but it is a plausible - if unlikely - outcome. Stay tuned
for any changes in the coming days.

After that, we look for the cooling/warming yo-yo for the second
half of the week. Low rain chances are expected, and with the
guidance coming in with less clearing behind the front than
before, have moderated the swing in temperatures. Spots way up in
Houston County may manage to dip into the middle 30s Wednesday
night, but freezing temps look less likely than the did before.

The next front looks...very difficult to forecast. The operational
GFS looks particularly goofy, as it creates an upper trough
bonanza around the Pacific coast, squeezing in the western ridge.
This slows up the front, which becomes weak and doesn`t make it to
our area until Sunday night. In the meantime, a little coastal
low/trough spins up and gives us some rain on Saturday. It`s
just...weird. I don`t like it - heck, the GFS` own ensemble
doesn`t even like it. The op run would be one of the driest
members, and IAH`s mean QPF by 192 hours is 1.6 inches (with the
wettest member at 2.82 inches) against an operational QPF of 0.91
inches. I`m much more a fan of the Euro, which builds a robust
western trough, allowing for northwest flow to power the front in
Sunday morning/early afternoon, and like the GEFS, is notably
wetter. Still, because of the wide range between the GFS and Euro,
I`ve spread the PoPs out some for the end of the forecast period,
as there is much time for the details to change. Another thing
worth noting - temperature forecasts are similarly impacted, with
the Euro considerably warmer than the official forecast at this
time range. I`ve nudged temps up from the last shift, but if the
Euro does indeed have the better handle on this timeframe, the
forecast will have to move up even more. Again, stay tuned.

MARINE...
Patchy fog will over the Gulf waters should briefly come to an
end as the cold front pushes out into the waters and boosts winds
to SCEC for 8-14 hours NE 15-20knots. The front stalls and comes
back quickly and currently upper 60 dewpoints are lurking 100+ nm
offshore. With the return of the warm front Monday night/Tuesday
morning the marine areas should have another round of sea fog that
continues until a cold front blows through Wednesday 4-9 pm. SCA
winds possible in the wake of the cold front. 45

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      42  61  54  72  48 /  10  10  40  50  70
Houston (IAH)              51  60  55  73  58 /  20  10  40  50  70
Galveston (GLS)            54  58  58  67  58 /  20  20  40  40  50

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Dense Fog Advisory until 3 AM CST Monday for the following
     zones: Houston...Madison...Polk...San Jacinto...Trinity...
     Walker.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 10 AM CST Monday for
     the following zones: Coastal waters from Freeport to the
     Matagorda Ship Channel out 20 NM...Coastal waters from High
     Island to Freeport out 20 NM...Waters from Freeport to the
     Matagorda Ship Channel from 20 to 60 NM...Waters from High
     Island to Freeport from 20 to 60 NM.

&&

$$

Discussion...31

Hazardous Weather Outlook

Hazardous Weather Outlook
National Weather Service Houston/Galveston TX
539 AM CST Sun Feb 4 2018

TXZ163-164-176>179-195>200-210>213-226-227-051145-
Austin-Brazos-Burleson-Colorado-Fort Bend-Grimes-Harris-Houston-
Liberty-Madison-Montgomery-Polk-San Jacinto-Trinity-Walker-Waller-
Washington-Wharton-
539 AM CST Sun Feb 4 2018

This hazardous weather outlook is for portions of Southeast Texas..

.DAY ONE...Today and Tonight

Patchy fog this morning could reduce visibility to below a mile
at times.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Fog could return Monday night and once again some of the fog could
become dense and reduce visibility to below a mile.

On Tuesday afternoon, an upper level disturbance could produce
scattered showers and thunderstorms. Some of the storms late
Tuesday and Tuesday night could become strong and produce hail.

Another storm system will approach on Saturday. This system has
some potential to produce moderate to heavy rainfall.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

$$

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