FEBRUARY 2019: Cold Front & Storm Chances

[Cpv17]

I don’t think those CFS maps posted by srain a while back are going to verify.

[tireman4]

000
FXUS64 KHGX 061058
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
458 AM CST Wed Feb 6 2019

.DISCUSSION...
An overall warmer environment, pre-dawn lower 70s, has severely
limited the interior occurrence and areal coverage of early
morning dense fog. Many sites are 3SM or greater along the
immediate coastline and the majority of the inland sites are
under low stratus with no fog. Due to the fact that the marine
environment hasn`t changed much (near 70 F dew points overrunning
upper 50 SSTs) thus keeping the threat for the redevelopment of
dense fog lowering visibilites to under a quarter of a mile high,
have left the Dense fog Advisory up for the barrier islands
through 11 AM.

Another warm and overcast day in store for us here in southeastern
Texas. Lowering western Plains pressure in relation to Florida
centered high pressure will significantly strengthen the onshore
pressure gradient and pick up today`s southerlies. Slight rain
chances do exist further inland today as eastern Texas falls on
the edge of weak diffluence centered around the Panhandle-centered
southern branch of the polar jet. As the lower level front enters
northwestern Texas tonight, there may be just enough lower layer
saturation to squeeze out a few light showers through the latter
part of the day. Despite the continued overcast, the above
mentioned warm air advection will overcome & conquer pushing
afternoon T readings into the upper 70s with maybe an 80 F or two
in the mix by sunset. The positive ENSO pattern is making its
presence known as early February temperatures nearing 80 F are
about 15 degrees above normal. Record maximum temperatures in the
lower 80s `should` be safe but it will be close....

Tomorrow`s cold front is timed to pass across the CWA (NW`ern
counties) through the late morning hours, passing through metro
by 2 or 3 PM and be off the coast just before sunset.
Frontogenesis-driven convection will mainly be in the form of
showers with isolated elevated storms possibly rooting to the
surface. The frontal passage is forecast to be fairly progressive
but, since it is coming through during the daytime hours, there
will be expected slowing and warmer, moist downstream air ingested
into any storm could provide enough instability to generate frequent
lightning and gusty winds. Late day north winds will regulate
Thursday`s warmth to the lower 70s, cold air advection will lower
Friday morning`s northern forecast area temperatures into the
average middle 30s/middle 40s over the southern counties.

A weak shortwave disturbance passing through within the southwesterly
flow Friday PM into early Saturday will increase the chance for
light precipitation over our northern tier counties. There is a
chance that this isentropic upglide-type precipitation may form as
a rain-sleet mix within the middle layers. A big question on
column moisture and above freezing lower level temperatures keeps
the mention of a frozen mix out of the grids, but this scenario
does warrant an early Wednesday AFD mention. Either way, any
frozen mix or snow flurries making it to the ground Friday will
be a non-impact event.

Cold air advection and mid to upper overcast will keep Friday and
Saturday cold with return flow on Sunday commencing the moisture
pump. Quite the difference between Saturday and Sunday`s weather.
Jacket weather Saturday as the day only warms into the upper 40s
to lower 50s. Increasing moisture through the day on Sunday will
warm the day into the average lower to middle 60s. A slight to low
end chance for showers, especially over the northern half of the
area as a series of weak disturbances pass around the northwesterly
periphery of a Florida Straits-centered upper ridge. A shortwave
trough passage across the Southern Plains Monday and a secondary
push in the form of a cold front Tuesday will increase early work
week shower chances. A downstream developing surface coastal trough
on Tuesday will target this day as the best chance for us to receive
low QPF measurable rain. Overcast, mild but not as warm (forecast
upper 60 to lower 70 maxTs) is the late period theme. 31

&&

.MARINE...
Sea fog remains the primary short term wx concern with a generally
stagnant pattern of warm air over cold water. Winds will be a bit
higher today and tonight so there should be some intermittent
periods of improved visibility compared to the previous several
days. That being said the threat for visibilities at or below 1nm
will exist until the next front pushes off the coast tomorrow. Right
now it appears that should occur around 3pm or so. Behind the front,
expect increasing northerly and northeast winds Thursday night thru
Saturday morning. Small craft advisories will be required and the
possibility of gale warnings will need to be looked at closer for
the 3am-9pm timeframe for the 20-60nm waters. Improving conditions
are expected Sunday & Monday as high pres moves off to the east and
an onshore flow resumes. Another front is penciled in for Tue. 47

&&

.AVIATION...
With the exception at the immediate coast where the sea fog threat
persists, fcst soundings show the current IFR/LIFR conditions
gradually scattering out this afternoon inland but soundings do show
MVFR ceilings hanging around between the coast and IAH. Winds look a
bit stronger today than previous days and will maintain the gust
groups already advertised in the TAFs. Ceilings will again lower
quickly after 00z with a mix of MVFR and IFR ceilings redeveloping.
Look for a band of shra and possibly an embedded tsra to move into
se Tx Thursday morning along a cold front. 47


.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 79 67 69 36 43 / 30 40 70 10 30
Houston (IAH) 79 68 73 42 46 / 20 30 80 10 30
Galveston (GLS) 72 65 68 48 51 / 10 20 80 20 20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Dense Fog Advisory until 11 AM CST this morning for the
following zones: Brazoria Islands...Galveston Island and
Bolivar Peninsula...Matagorda Islands.

GM...Dense Fog Advisory until 11 AM CST this morning 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.

&&

$$

Discussion...31/47

[jasons2k]

My forecast low for Friday night is holding at 39. This morning,
I noticed the trees are really starting to bloom now. I’m thinking the freezes are done and Spring is here.

[Katdaddy]

The cold front will be moving across SE TX this afternoon and off the coast this evening with scattered showers and a few thunderstorms. Back to the 40s as Winter say’s hello again.

[srainhoutx]

Big weather changes ahead today as a strong cold front nearing Austin pushes offshore by Sunset this evening. Gusty Northerly winds bring cold air advection across the area tonight. The current forecasts suggest we bottom out in the mid/upper 30's inland and near 50F along the Coast. The latest NAM solution which can be on the colder side of guidance suggests some locations near HYW 105 may flirt with a light freeze tomorrow morning.

[jasons2k]

The mild weather has been nice. The cold snap should be brief and my lowest forecast low is 38, then back to mild weather again.

[Montgomery]

Looks like after Saturday, we stay warm for a good period.

[Electric Lizard]

The front just got to southwestern Washington County,

[srainhoutx]

Friday morning weather briefing from Jeff:

Strong cold front will cross the region today ending the record warmth.

A high temperature record of 82 was set yesterday at BUSH IAH, and temperatures will be a solid 30-40 degrees colder by Friday morning. Cold front currently extends from about Crockett to just north of Brenham and will move off the coast by late afternoon. A line of showers and thunderstorms has developed along this boundary and will spread across much of the area through the day. Air mass is unstable aloft and a few of the storms could be strong with small hail and gusty winds. High temperatures will be prior to the front in the mid to even upper 70’s followed by a rapid fall into the 50’s under cold air advection this afternoon. Cold air will continue to flow into the region tonight with temperatures falling into the upper 30’s and low 40’s.

A disturbance will move across the area on Friday and Friday night within the cold air mass. Recent forecast soundings show a deep layer a dry air near the surface up to about 15,000 to 20,000 ft which should result in much of the cloud based precipitation evaporating after leaving the cloud base. This large layer of dry air will try to saturate from top down toward the surface during the day Friday and into Friday evening and this may succeed in a few isolated locations allowing a mixture of rain/sleet/snow to reach the surface. Suspect anything would be extremely light and given the fact that surface temperatures will be in the mid 30’s not expecting any issues. Most likely locations for seeing any mixed precipitation Friday evening would be north of a line from Brenham to Huntsville….again think these chances for very small.

Coastal trough begins to form on Saturday and strong warm advection begins in the 925-800mb level. Expect to see little temperature movement on Saturday as clouds and NE winds keep the surface cold dome locked in place. A warm front will begin to approach the coast early Sunday and the air mass will undergo top down warming and gradual moistening. Expect to see scattered showers develop especially west of I-45 on Sunday and this wet pattern will last into Monday and Tuesday ahead of our next front. Temperatures will be up and down with both cold and warm frontal passages over the next several days. Cold Friday and Saturday and then warm again Sunday-Monday.

Active pattern looks to remain in place with a continued wettish looking period next week and even the following week with no significant cold air intrusions showing up in the extended models that would be out of the ordinary for February. Cold air will be lurking in the northern plains and northern Rockies, but currently not seeing a great pattern to deliver a big chunk of this toward TX.

[MontgomeryCoWx]

Going to feel great this weekend!

I actually had to mow yesterday. Put down turf builder this past week. Yuck.

[mcheer23]

Can't wait for high temps to be in the mid 40's tomorrow.

[BlueJay]

YIKES!!! the front is here. The sun has vanished, the skies have significantly darkened, the wind is gusting and I can feel the cold air coming in through the windows. I guess the rain is not to far behind.

Oh yes. "Winter" continues. Time to get a sweater.

[tireman4]

00
FXUS64 KHGX 071811
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1211 PM CST Thu Feb 7 2019

.AVIATION...
Gusty NNW winds accompanying the wind shift with 20-60 mile wide
band of -RA/SHRA. MVFR ceilings/visibility with the FROPA then
improving quickly to VFR. Patchy sea fog still in place at the
coast. No big changes to the forecast. Mid and upper level VFR
deck to persist 00z-18z.

45


&&

.PREV DISCUSSION... /ISSUED 1026 AM CST Thu Feb 7 2019/

UPDATE...

For the most part, the big picture forecast is going pretty well
as a cold front enters the area from the northwest. Changes to the
forecast were made to better reflect observations. This includes
slight tweaks to temperature, dewpoint, and winds through tonight.

More significant alterations were made to PoPs and to visibility
grids, in attempts to tighten up gradients as we have
satellite/observations to help refine fog near the coast, and
radar information to better inform the coverage and speed of a
line of showers and isolated thunderstorms on the cold front.
The general idea of a progressive cold front with a weakening line
of showers and storms stays the same, but the new forecast
hopefully is a more accurate representation based on the latest
data, with more certainty in the first few hours.

[Cpv17]

The mild weather has been nice. The cold snap should be brief and my lowest forecast low is 38, then back to mild weather again.

We’ve basically been living in a soup bowl these past few days. How’s that been nice? Lol

[unome]

i just love our HGX crew

Indeed, the general trend in the models is a drier one. Still...that dry air allows for a wet bulb profile that is entirely below zero...and just screams to me, "lots of people are gonna get cell phone video of about 10 sleet pellets pinging offtin roofs and cars". So, in deference to the fact that if we get enough precip to evaporate and saturate a wet bulb profile, a few sleet pellets might just survive to the ground. Indeed, if we`re cold enough that ice crystals are generated, there`s an even smaller chance of a snowflake or two. I begrudgingly added these to the grids in the morning, on the off chance it happens. Very high confidence that even if some frozen precip is observed, that impacts will be nil.

full disco:

Code: Select all

Area Forecast Discussion
National Weather Service Houston/Galveston TX
347 PM CST Thu Feb 7 2019

.DISCUSSION...

Quite warm at the coast today as the front didn`t quite make it in
time to cut those temps off...but things will turn decidedly
colder for the entire area tonight. Though low level dry air will
try to keep things dry, some lingering precip tomorrow morning
might result in a few sleet pellets!

We`ll be cool through the first half of the weekend, then warm
strongly into early next week. But like most everything (except
the fog) lately, the active pattern will keep `er movin` and
another cold front will cool things down some for the mid-week and
bring another chance for rainfall.


.NEAR TERM [Through Friday Morning]...

The cold front has cleared the coast and gusty north winds have
started across Southeast Texas. Galveston ob suggests I could try
to justify a short wind advisory for the barrier islands, think
that the period of 25 mph sustained winds will be too short to
make one necessary. Though radar shows some showers lingering
behind the front, we`ve lost the instability for any trailing
thunderstorms, and those coastal showers should come to an end
this evening.

Temperatures will continue to nosedive through the night, and we
could flirt with freezing temperatures from College Station and
Huntsville northward. This...sets us up for something interesting
tomorrow morning. A weak little vort max embedded in southwesterly
flow looks to cross the area tomorrow morning, and could generate
some precip. The thing is, forecast soundings show only a very
shallow cloud layer and very dry air sub-cloud. Odds are, any
precip that is generated evaporates/sublimates and nothing reaches
the surface. This would be in line with what the HRRR and RAP
suggest. Indeed, the general trend in the models is a drier one.
Still...that dry air allows for a wet bulb profile that is
entirely below zero...and just screams to me, "lots of people are
gonna get cell phone video of about 10 sleet pellets pinging off
tin roofs and cars". So, in deference to the fact that if we get
enough precip to evaporate and saturate a wet bulb profile, a few
sleet pellets might just survive to the ground. Indeed, if we`re
cold enough that ice crystals are generated, there`s an even
smaller chance of a snowflake or two. I begrudgingly added these
to the grids in the morning, on the off chance it happens. Very
high confidence that even if some frozen precip is observed, that
impacts will be nil.


.SHORT TERM [Friday Afternoon Through Saturday Night]...

Thanks to north winds and cold advection, Friday will be a good 30
degrees or so colder than the beginning of the week. The north
will struggle past 40 degrees, and only the immediate coast may
see 50. Saturday only looks to be a few degrees cooler. But, low
level flow from the Gulf should resume Saturday, and temperatures
should only dip slightly into Saturday night in advance of a
warmup for Sunday. A consistent stream of subtle vort maxes in the
southwest mid-level flow will keep rain chances from going all the
way to zero at any point in the short term, but we should only be
looking at a handful of sprinkles or light rain showers in the
end. Most anything that falls will continue to work to moisten the
extremely dry atmospheric column.


.LONG TERM [Sunday Through Thursday]...

We take full advantage of the resuming onshore flow, and the
lower coast may even have a chance at cracking 70 degrees. Up
north will be cooler, underneath cloud cover and some light
isentropic upglide showers. Most of the precip should be north of
our area, but B/CS/Crockett and the like will have a better shot
than most to have some light rain hold temps back. While Monday
should have another chance at light upglide showers across the
area in advance of the next front, the persistent onshore flow
should really help warm things up...

...just in time for another cold front on Tuesday. Timing will be
extremely important as far as temperatures are concerned. If it`s
a later front, we`ll see a pattern similar to today - cooler up
north, but quite warm near the coast before the front arrives.
Winds in the current forecast indicate a slight speed-up in the
front`s arrival, so I did not get as crazy as I could have gotten
with Tuesday highs near the coast. Still, temps on Tuesday will be
very sensitive to frontal timing. Less sensitive will be rain
chances. I get aggressive Monday night into Tuesday for rain on
the front, with some lingering chances deep into the week as both
the GFS and Euro build a weak surface trough over the Gulf waters
nearby. This should also limit our offshore flow/cold advection
post-front, so I`m conservative in knocking temps down late week.

&&

.AVIATION [21Z TAF Update]...

Rapidly improving conditions in the wake of the front with VFR
weather. Mid to upper level cloud deck to remain through Friday then
Saturday will start lowering as lower level flows begin to veer to
the east and moistens back up. MVFR possibly return as early as
Saturday.
45

&&

.MARINE...

Cold front pushing off Galveston/Freeport/Matagorda Island at 2 pm.
Fog has departed the bays and is ending in the nearshore waters.
Showers dotting the frontal boundary but becoming less widespread as
it continues to push out into the Gulf. Gusty NNW winds in the wake
of 20 to 30 knots but expect a short term drop in the winds before
picking back up around 6-8 pm time frame. Still looks to warrant the
SCA/Gale and will be continuing the Gale Warning. SCA after it ends
will likely be needed for at least another 12 hours and possibly
longer. Winds will remain strong to moderate north to northeast
through Saturday as high pressure parks over NETX and lower
pressures linger on the Lower Coast this weekend. Approaching s/w
Saturday night helps to veer winds to the east and then eventually
back to the southeast Sunday night/Monday. Threat of fog will likely
return early Monday and prevail through the next frontal passage on
Tuesday.

Tides are an issue with the persistent north and northeast flow the
next few days and can`t quite rule out the need for a low water
advisory at some point...Friday night low tide cycle the more likely
candidate.

45

&&


.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL)  32  42  38  44  41 /   0  30  30  30  40
Houston (IAH)          40  47  40  47  43 /  10  10  20  20  20
Galveston (GLS)        47  49  44  52  50 /  10  10  20  20  20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...None.
GM...Small Craft Advisory until noon CST Friday 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.

     Small Craft Advisory until 9 PM CST this evening for the
     following zones: Waters from Freeport to Matagorda Ship
     Channel TX from 20 to 60 NM...Waters from High Island to
     Freeport TX from 20 to 60 NM.

     Gale Warning from 9 PM this evening to noon CST Friday for the
     following zones: Waters from Freeport to Matagorda Ship
     Channel TX from 20 to 60 NM...Waters from High Island to
     Freeport TX from 20 to 60 NM.


&&

$$

NEAR TERM...Luchs
SHORT TERM...Luchs
LONG TERM...Luchs
AVIATION...45
MARINE...45

[jasons2k]

Wow, lowered to 37F tonight and then 38F tomorrow night. That’s a bit of a shift downward but at least no freeze to worry about. It’s just an excuse to burn another fire so I’m happy about that. Oh and I just got used to running in the cold, too, so I’m prepared

[Belmer]

18z GFS has widespread 80s with pockets of 90s in Texas next weekend. Even flirting with triple digits along the Rio Grande.

Surely that will verify...

Though, GFS FV3 is 20-30 degrees 'cooler' with more seasonal temps.

[jasons2k]

I would not be surprised, either way.

[DoctorMu]

Looks like I was right about the cold. A bit of advection, but it's pretty modified. Overrun conditions, but not much chance of wintry stuff tomorrow here. Still a chance of icy, sleet-like conditions in the Hill Country.

[Katdaddy]

Last night forecasted temps for this morning from the HOU-GAL NWS are right on target. Enjoy the Winter weather today and Saturday. Back to mid 70s Monday followed by another cool front next week. Clouds and some showers continue through next week.