FEBRUARY 2019: Cold Front & Storm Chances

[Katdaddy]

The cold front is slowing moving across the Upper TX. The front passed through Houston with temps in the low 60s now while its 75F in Angleton. It will stall along the coast or just offshore before moving back inland tonight. A few brief rays of sun would be nice but not likely today. Perhaps tomorrow some brief sun before, you guessed it………more gloomy and wet weather arrives Monday through next weekend. BLAAAAHHHHH!!!

[mckinne63]

Very overcast this morning. Had some drizzly rain this morning. We were going to cut our palm fronds, but everything is very damp outside.

[BlueJay]

Peeks of sun for us on this chilly afternoon.

[mckinne63]

The sun! The SUN! I see the sun!

[Katdaddy]

Well the clearing moved across the Upper TX Coast this afternoon resulting in a beautiful mostly sunny evening followed by a beautiful sunset. Very well needed after the gloomy skies and the sun was so refreshing!!!

[srainhoutx]

We'll need to monitor for the potential of heavy training rainfall and possibly some stronger storms capable of dropping some isolated small hail Tuesday into Tuesday night. A vigorous storm system ejects into the Plains and a Coastal Low/Trough with favorable dynamics associated with upper level disturbances riding a very noisy sub tropical jet may bring some weather excitement to the area.

[Texaspirate11]

Hey it`s El Nino what did you
expect sunshine and dry?
45

Good one, NWS

[Cpv17]

We'll need to monitor for the potential of heavy training rainfall and possibly some stronger storms capable of dropping some isolated small hail Tuesday into Tuesday night. A vigorous storm system ejects into the Plains and a Coastal Low/Trough with favorable dynamics associated with upper level disturbances riding a very noisy sub tropical jet may bring some weather excitement to the area.

What makes you say that? None of the models I’ve looked at have more than 1-2” across our area for the whole week. The heavier training rainfall appears to be well north and east of us.

[Belmer]

I think the key word in Steve's post was 'potential' though chances are fairly low. Great discussion by Overpeck today from the NWS -

Area Forecast Discussion
National Weather Service Houston/Galveston TX
252 PM CST Mon Feb 18 2019

.NEAR TERM [Through Tonight]...

Temperatures this afternoon have reached the mid 60s with a
steady stream of thin high clouds with some breaks. High pressure
continues to build over the Plains keeping NE winds in place over
SE Texas with dewpoints in the 30s. Frontal boundary continues to
push into the central Gulf slowly. Overall it has been a nice day
to be outside and enjoy.

Upper level analysis from 12Z upper air data shows a very potent
jet stream from west Texas NE to New England today with an upper
low approaching the Four Corners region. Jet streak and vorticity
maximum seen in water vapor imagery along the California coast
should continue to round the base of the low tonight into
tomorrow. As this happens, model guidance shows isentropic lift
increasing overnight in response to lowering 850mb heights in the
lee of the Rockies. Isentropic lift should be ongoing on just
about any level, but the 295K theta surface seems to be in the
thick of it all.

All this means is that moisture will be riding over the frontal
surface leading to drizzle, rain and eventually fog tomorrow
morning. Fog looks to be somewhat delayed and a function of
drizzle. To avoid any weather type confusion, forecast will read
showers but there will be a mix of drizzle/light rain when there
are not showers passing.

Overpeck

.SHORT TERM [Tuesday Through Wednesday Night]...

Tomorrow it is going to rain for a number of reasons. First there
is the aforementioned isentropic lift that only increases during
the day which will support areas of showers. As the upper low
moves into the southern Rockies, the right entrance region of the
upper level jet becomes more oriented over SE Texas allowing for
large scale ascent for more rain. Next in response to this jet
streak, there is an increase in the LLJ in which by tomorrow
afternoon there could be 850mb winds near 40 knots across the
eastern half of the area. This will serve as a moisture axis as
well helping to channel shower activity. After that, let`s throw
in an increase in moisture with precipitable water values around
1.7 to 1.8 inches for the eastern half of the forecast area
aligned with the LLJ. Looking at forecast soundings, lapse rates
will be enough to support elevated thunderstorms. Recent SPC day 2
outlook has a marginal risk drawn closer to the forecast area
than before. Given the set up of the LLJ this seems to make sense
and where elevated convection may be strongest for a hail/wind
threat. Individual storms will be moving quickly from S/SW to N/NE
so rainfall rates may not be quite as high. Rain rates may also
be limited due to the instability being elevated and not as robust
as compared to surface based convection. A coastal low should
develop along the front tomorrow and move along it up the Upper
Texas Coast. This will continue to help pump moisture north and
increase tide levels at the coast. Not only that, there is the
small chance the warm sector could move just inland but guidance
is consistent with keeping the warm sector airmass just inland of
SW LA. This might be where there is a slightly higher threat for
severe weather than SE Texas.

Where may we expect higher rainfall amounts tomorrow? First along
the LLJ and moisture axis. Hi-res models keep this mainly east of
I-45 but still a chance it could be centered to the west. Even
then, rainfall totals look to be around a half inch with passing
showers albeit somewhat training. The second location will likely
be from Huntsville to Lufkin NE into the Arklatex where 850mb
frontogenesis will be maximum. Models are really hitting areas NE
into Arkansas with the higher rainfall amounts over 1 inch. Closer
to SE Texas along this axis, rainfall amounts look to be between
a half inch and an inch. Again a solid half inch to an inch of
rain across the area probably will not cause much of a flood
problem although given very moist soils, any rainfall should run
of pretty quickly. There could be some rapid rises on area creeks
and bayous but likely stay in banks.

A cold front should push through in wake of this upper level
trough and push into the Gulf Wednesday night. The front then
stalls as upper level flow remains from the SW and another trough
forms over the Great Basin by Thursday morning.

Overpeck

.LONG TERM [Thursday Through Monday]...

We are going to quite literally write wash...rinse...repeat for
this part of the forecast discussion for Thursday through Saturday
and then again next Monday and Tuesday. You can pretty much copy
what was written above and insert hear for the discussion of the
Friday/Saturday system, take a break Saturday night into Sunday
and copy it again for Monday next week. Now there is more
uncertainty in the details for next week but there is some model
consistency to be had. That means we will be looking at another
half inch to an inch of rain for the area and the sogginess
continues (thanks El Nino).

Overpeck

[Texaspirate11]

We're going to be in this wet pattern for a while.
Like our NWS said
"THANKS, EL NINO"

[jasons2k]

I think the key word in Steve's post was 'potential' though chances are fairly low.

Yep. The threat was also mentioned in Jeff’s email this morning.

Chilly game at the fields tonight. Late game, too.

[srainhoutx]

Tuesday morning briefing from Jeff:

A wet weather pattern will be in place for the next several days.

A coastal surface low has formed over the NW Gulf of Mexico this morning and has really tightened the pressure gradient over the region. Winds at 600am were gusting to 28mph at IAH and nearly 30mph along the coast out of the E and NE. Radar shows an expansion of the showers and drizzle over the region with a few thunderstorms especially up north and east of Houston where NLDN has shown a few strikes this morning.

Warm front is advancing toward the coast with good lifting of the air mass over SE TX as a warm southerly flow aloft overruns the cool NE winds at the surface. Moisture levels have greatly increased overnight with Lake Charles PWS rising from .85 of an inch into the 1.0 inch range and a reservoir of 1.5 inches is shown just off the coast moving northward. Radar is much more convective looking than expected, but coverage is also not as widespread as expected thus far. Will focus the heaviest rains today NE of Houston where good 850mb frontal lift is most likely and taper amounts lower toward the SW around Matagorda Bay. Rainfall amounts of 1-2 inches will be possible around Lake Livingston with .50 to 1 inch around Houston and then .25 of an inch around Matagorda Bay. Warm front may get close to the coast this afternoon, but think it will remain just offshore and keep the entire region in the cool sector (lower 50’s).

Surface low will move NE of the area tonight allowing a slightly drier air mass to filter in, but enough to reduce rain chances and maybe even have a little sun on Wednesday. Next short wave in the active sub-tropical flow approaches the area starting Wednesday night with the old Gulf cold front stalling offshore and another surface low forming along the boundary. Entire process of today will repeat on Thursday into Friday with a coastal low moving NE along the coast, but this time a warm front looks to swing further inland. Will bring rain chances back on Thursday and maintain into Friday and Saturday although Friday if the warm sector can move decently inland may end up more cloudy and humid than actually wet.

Next short wave approaches on Saturday and this one looks fairly strong. Decent shear and instability may be able to develop over SE TX with a more well defined arm sector air mass in place Friday and Saturday. Parameters are marginal, but pointing toward some strong to severe thunderstorms Saturday afternoon and evening with the passage of our next cold front. This system should be strong enough to send the post frontal air mass well out into the Gulf of Mexico and allow at least a day of dry weather on Sunday.

Active sub-tropical flow out of the Pacific refuses to abate and the next short wave loads into the SW US and ejects toward TX early next week with the entire pattern repeating with a coastal surface low forming along the coast spreading rain inland over a cool surface air mass. In fact the latest guidance progs keep a fairly active and wet pattern in place through the end of the month.

[tireman4]

Interesting factoid

[Cpv17]

I thought it was supposed to be raining this morning lol

[tireman4]

00
FXUS64 KHGX 191142
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
542 AM CST Tue Feb 19 2019

.AVIATION...
Low pressure and an associated warm front will approach SE TX
today. Ceilings are expected to lower in advance of the warm
front. MVFR cigs will transition to IFR between 16-18z and could
fall to LIFR by 21z. Bands of precipitation are expected to move
into the area from the south through 20z and then slowly diminish.
Best dynamics are over the northern TAF sites and a few isolated
thunderstorms will be possible. Once the surface low move north of
the region, it`ll drag a cod front across the area between 08-12z.
Cigs/vsby will improve in the wake of the front. Prior to the
improvement, patchy fog and drizzle will be possible.

&&

.PREV DISCUSSION... /ISSUED 437 AM CST Tue Feb 19 2019/

DISCUSSION...

Low level moisture continued to pool into the region and resulted
in overcast skies as well as passing showers mainly across the
Gulf waters into the southern portions of the forecast area
overnight and early this morning. Tight local pressure gradient
resulted in a moderate to strong wind flow, particularly over the
coastal regions and coastal waters. Winds generally from the east
at 5 to 15 MPH inland and at 25 to 30 MPH with higher gusts
across the Gulf waters were observed overnight and early this
morning.

Surface low located over the western Gulf of Mexico will continue
to move north northeast today. Ahead of the low, an associated
warm front will provide sufficient lifting for additional shower
development across the region. Model consensus shows the core of
the low entering the Gulf waters around late morning/early
afternoon. Increase in shower and isolated thunderstorm activity
can be expected during the late morning hours and continues
through the night as an upper level trough approaches and moves
across the local area. As stated in the previous forecast package,
model guidance shows the right entrance region of the upper level
jet moving closer to the SE Texas region later today as well as
an increase in the low level jet, which in combination with the
southerly moist air mass, favorable 500mb vorticity as well as
divergence aloft, supports the development of scattered to
numerous showers and isolated thunderstorms across the region
today. PWAT values for today range from 1.50 to around 1.80
inches.

The surface low should exit near the southeastern portions of the
CWA this evening/tonight and the cold front associated to the
upper level trough should move across the local area Wednesday.
Shower activity is forecast to decrease Wednesday morning but
increases once again Wednesday night as low level moisture
increases over SE TX. With respect to the winds, velocities will
decrease today and a southerly wind flow will set in this
afternoon and evening. However, winds will once again increase and
become northerly overnight and early Wednesday morning.

During the rest of the forecast period, a wet weather pattern is
expected to continue as several surface coastal lows and upper
level troughs move in and out of the region. Periods of showers
and isolated thunderstorms are forecast throughout the long term
period with a few rests in between when drier air pools across
the local areas in the wake of the cold fronts. This will also
continue to result in fluctuating wind direction and speed during
the next couple of days. 24

MARINE...

A fairly complex/changing marine forecast this week with virtually
all kinds of hazards in play at some point. Low pressure off the
Mexican coast will move north today and should approach Galveston
Bay this evening. The pressure gradient will remain tight this
morning but will begin to weaken from south to north as the low
moves north. Will maintain the SCA for the Gulf waters through 18z
but replace the SCA over the bays with a SCEC. The low will bring a
warm front north and this feature will bring periods of light rain
to the coastal waters. The surface low will move into Arkansas
tonight and the low will drag a cold front across the coastal waters
late tonight. A moderate to occasionally strong offshore flow will
develop in the wake of the front as high pressure builds into the
southern plains. Another area of low pressure will develop off Deep
South Texas on Thursday and this feature will take a similar track
and approach SE TX by late afternoon. Warmer and more moist air will
flow over the cooler shelf waters and a brief period of sea fog will
be possible Fri/Sat. Another cold front on Sunday should clear the
fog with a moderate offshore flow.

Strong east winds this morning will boost tide levels and water
levels could briefly reach or exceed 3 feet early this morning.
since the impact will be very localized and the duration so
short, will forego a coastal flood advisory. 43

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 48 41 62 43 57 / 90 40 10 30 50
Houston (IAH) 56 48 63 49 59 / 90 50 20 40 60
Galveston (GLS) 65 53 63 57 64 / 90 60 40 50 60

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until noon CST today for the
following zones: Galveston Bay...Matagorda Bay.

Small Craft 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.

Small Craft Advisory until 3 PM CST this afternoon 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.

&&

$$

Discussion...25
Aviation/Marine...43

[Cromagnum]

I thought it was supposed to be raining this morning lol

It dampened my driveway south of town. If that's all we get, it will be great. Need 2-3 weeks with zero rain so I can mow and treat my jungle of a backyard

[tireman4]

000
FXUS64 KHGX 191656
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1056 AM CST Tue Feb 19 2019

.DISCUSSION...
No significant changes planned for the grids for this afternoon as
conditions remain favorable for the development of widespread SHRA
(and isolated TSRA). Moderate to strong onshore winds (courtesy of
the coastal low over the Lower/Middle TX coast) will help keep the
moisture levels elevated over the area today/tonight. While we are
getting a bit of break from the stronger overnight activity at pre-
sent...radar is indicating increased coverage near/along the coast
with the last several scans. This activity is expected to eventual-
ly spread inland through the rest of the day. 41

&&

[tireman4]

Special Weather Statement
National Weather Service Houston/Galveston TX
1118 AM CST TUE FEB 19 2019

TXZ177-178-199-212-213-191745-
San Jacinto TX-Walker TX-Waller TX-Inland Harris TX-Montgomery TX-
1118 AM CST TUE FEB 19 2019

...SPECIAL WEATHER STATEMENT...

At 1118 AM CST, Doppler radar was tracking a strong thunderstorm over
Pinehurst, moving northeast at 55 mph.

Half inch hail will be possible with this storm.

Locations impacted include...
Conroe, Tomball, Willis, Pinehurst, The Woodlands, Panorama Village,
Magnolia, New Waverly, Montgomery, Stagecoach, Huntsville State Park
and Lake Conroe Dam.

LAT...LON 3003 9567 3012 9585 3064 9556 3051 9529
TIME...MOT...LOC 1718Z 210DEG 49KT 3020 9569

$$

[tireman4]

Radar Image

[CrashTestDummy]

I thought it was supposed to be raining this morning lol

It dampened my driveway south of town. If that's all we get, it will be great. Need 2-3 weeks with zero rain so I can mow and treat my jungle of a backyard

We've had 0.08" so far today. That's still too much. Need 2-3 weeks with zero rain so we can smooth out the trenches my wife created trying to mow the back yard a couple of weeks ago burying the tractor up to it's hubs. We could only get to about 1/3 of the yard then.

I'm afraid that the rain is just starting for this week.