MAY 2019: Wednesday Storm Complex/Scattered Showers To End May

[Katdaddy]

A slight chance of showers and a few thunderstorms today and Wednesday. A few light streamer showers have moved inland along the Upper TX Coast early this morning. Received 0.02” at 3AM from one of the light streamer showers.

Dayton, OH was struck by 2 tornadoes overnight with extensive damage. 60 tornadoes have been reported to the SPC yesterday. Another active severe weather day across the Central Plains, Midwest, Ohio Valley and portions of the Northeast.

[jasons2k]

So sad to hear about Dayton. This is a crazy season.

Rain chances for Thursday back up to 60%.

[unome]

Tornado report counts for last 2 wks are mind boggling

on the up-side, there is at least some chance of rain across every day, through Sunday, in my forecast - liking that, even if it's just cloudy it will help

[tireman4]

000
FXUS64 KHGX 281109
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
609 AM CDT Tue May 28 2019

.DISCUSSION...
Per KHGX radar, we are seeing a couple of areas of light rain mov-
ing into the region this morning. A jet streak tracking across the
Southern Plains is helping to produce some light activity over the
far northern third of the CWA. Closer to the coast, strong WAA off
the Gulf is also producing streamer showers across these locations.
Most of this activity is expected to mix out by late morning...but
isolated/widely scattered showers will be possible later this aft-
ernoon. Otherwise, this warm/humid weather will continue today. We
should see similar conditions tomorrow as the overall larger scale
meso features remain in place (i.e. upper trof axis lingering just
west of the Rockies, with SE TX on the periphery of the deep ridge
over the northern Gulf).

Rain chances will be increasing for Thur/Fri as a couple of strong
shortwaves help to nudge this aforementioned upper trof a bit more
to the east...then/also dragging a very weak surface boundary into
the region from the NW. These features along with progged PWs near
2 inches and a somewhat favorable jet pattern aloft are supportive
of organized showers/thunderstorms Thur afternoon/evening and once
again on Fri...with the best rain chances across the northern half
of our CWA. But that being said...a lot will depend on the surface
boundary and where it stalls. Have kept with the previous forecast
trends of mainly afternoon/early evening activity and with progged
storm/event rainfall totals ranging from around a quarter inch at/
just north of I-10 to around a tenth of an inch south.

The building upper ridge (in the wake of these storms) will lower
POPs for the weekend as temperatures rise. 41

&&

.Aviation...
Mix of mainly VFR with some patchy MVFR early this morning becoming
VFR between 14-16z. S/W approaching from the southwest leading to
some drizzle/sprinkles/-RW over the CLL-UTS-DKR-AUS region as well
as a few nocturnal marine showers nearing the GLS-BPT area. For now
will hold off on any mention of -RA/SHRA for IAH/HOU as these may be
too far northwest and east of the terminals. SSE winds today 12-
16G18-25kt for most of the inland sites beginning around 15-16z.
Winds relaxing slightly tonight with an increasing chance of
MVFR ceilings developing between 04-08z.
45

&&

.MARINE...
SCA conditions expected over the Gulf Waters and SCEC bays. Over the
Gulf winds should be bouncing around between 16-22kts with gustier
conditions over the Bays. Seas of 4-6 feet this morning gradually
increasing this morning then slowly lowering Wednesday morning as
winds gradually weaken. Cold front could sag out of SETX late
Thursday night/Friday morning with storm activity otherwise winds
more easterly and lighter. Tides remain .8 to 1.5 feet above normal
and with the increase in seas today expect the rip current to
strengthen so have extended the Rip Current statement into
Wednesday. Rip current should steadily weaken Thursday though the
tide levels will probably remain elevated.
45

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 90 74 90 73 88 / 10 30 30 40 50
Houston (IAH) 90 75 91 76 89 / 20 20 20 40 50
Galveston (GLS) 86 78 86 79 86 / 30 20 20 30 30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Wednesday morning for the
following zones: Brazoria Islands...Galveston Island and
Bolivar Peninsula...Matagorda Islands.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION through Wednesday morning
for the following zones: Galveston Bay...Matagorda Bay.

Small Craft Advisory until 7 AM CDT Wednesday 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...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.

&&

$$

[tireman4]

000
FXUS64 KHGX 281751
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1251 PM CDT Tue May 28 2019

.DISCUSSION...

18Z Aviation...Scattered SHRA are expected to continue through
around 20Z from SGR to CXO and eastward. MVFR ceilings will return
overnight and continue into Wed morning. S/SE winds will subside
some this evening. 33

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 74 90 73 88 72 / 20 30 40 50 30
Houston (IAH) 75 91 76 89 75 / 20 10 40 50 20
Galveston (GLS) 78 86 79 86 78 / 20 0 30 30 20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Wednesday morning for the
following zones: Brazoria Islands...Galveston Island and
Bolivar Peninsula...Matagorda Islands.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION through Wednesday morning
for the following zones: Galveston Bay...Matagorda Bay.

Small Craft Advisory until 7 AM CDT Wednesday 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...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...33

[tireman4]

000
FXUS64 KHGX 291008
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
508 AM CDT Wed May 29 2019


.SHORT TERM [Tonight Through Thursday Afternoon]...
Gusty south-southeast winds this morning pumping in the moisture
and keeping temperatures well above the normals of 70-75. Mix of
cloud decks blanketing much of the region with a few sprinkles
that have been mainly focused over the southwestern counties.
These should expand inland and could reach College Station area by
mid morning. Amounts should be very light. Winds over the Gulf
waters support a continuation of the SCA and SCEC for the bays and
the bays could be borderline SCA this morning especially Matagorda
Bay. Seas of 4 to 7 feet with 16-23kts should gradually diminish
this afternoon. Tide levels still elevated LLJ this morning
stretches from Brownsville to Austin to Little Rock and northeast
helping to the fuel the storms in Arkansas and Illinois. A cold
front was draped over West Texas/Oklahoma/Missouri. This cold
front will become an issue for SETX Thursday. Upper troughing over
NM will lift out and focus storms along and near the boundary
today as it moves through N TX with the front sagging south
tonight and into northwest counties of the CWA or just north of
the CWA by 6 am Thursday which keeps SETX in the warm sector and
continued well above normal temperatures. The front slides
southward Thursday though the push of cold air is weak expect that
storms were firing off along the boundary in the morning throw in
a little rain cooled outflow to muddy the actual frontal
boundary. By afternoon the rain-cooled boundary/front should be
draped west to east across the region and differential heating and
weak winds will likely lead to scattered to numerous showers and
thunderstorms in a band across the region. These storms will be
slow moving and could produce brief periods of heavy rain and
gusty winds maybe even some small hail. CAPE is plentiful at
2200-3600 j/kg-LI -6 to -9 and PW 1.8 to 2.1" and little if any
capping. Rainfall amounts will vary widely with some places dry
and others with .25 to 2-3 inches. Storm motions around 10 knots.
Mesoscale rules apply as any frontal forcing wanes.


.LONG TERM [Thursday Night Through Wednesday]...

Given the possibility of the frontal boundary (or leftover outflows)
lingering over the northern half of the CWA along with elevated PWs,
somewhat favorable jet positioning and daytime heating, did keep 40-
20% POPs in for Fri. While there may be questions as how worked over
the air mass over SE TX could be, models have remain consistent with
this "second" round on Fri with one last shortwave ejecting eastward
into the base of the trof deepening over the eastern U.S. seaboard.
This, in turn, should help to amplify the upper ridge over the state
(Southern Plains). Warmer temperatures and decreased POPs will be on
tap for this weekend...and likely into the first half of next week.
Rain chances should be limited to mainly isolated activity along the
seabreeze during the afternoon.

For the coastal waters, no significant issues are expected as light/
moderate onshore winds prevail.


&&

.CLIMATE...

Record high minimum in jeopardy at Hobby for today given the warm
start this morning and the moderate onshore flow to persist
through tonight.

Record high minimum...77 set in 1996.
Forecast minimum......79

&&

.AVIATION...
Mix of MVFR/VFR CIGS across the area with more clouds streaming
from the nearshore waters and being tapped by the LLJ to the west
of the area and eastern edge arcing up over the ARM-UTS area. May
be close to LLWS conditions near UTS early this morning. Ceilings
should rise quickly 13-15z becoming VFR then MVFR again tonight
after 02z. Gusty winds will continue into the afternoon hours then
gradually relax this evening as pressure gradient relaxes. Will
probably need to add at least VCSH to CLL for the afternoon hours
today and VCTS after 12z/Thursday for IAH with the increasing
showers/thunderstorm chances as boundary slides southward. MVFR
ceilings will probably linger later into the morning hours across
the area Thursday as well.

45

&&
.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL) 91 73 88 71 88 / 40 50 50 30 40
Houston (IAH) 91 74 89 75 90 / 20 40 60 30 30
Galveston (GLS) 86 79 86 79 88 / 10 30 40 20 20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...High Rip Current Risk until 2 PM CDT this afternoon for the
following zones: Brazoria Islands...Galveston Island and
Bolivar Peninsula...Matagorda Islands.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 2 PM CDT this
afternoon for the following zones: Galveston
Bay...Matagorda Bay.

Small Craft Advisory until 2 PM CDT this afternoon 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 11 PM CDT 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.


&&

$$

SHORT TERM...45
LONG TERM...41

[tireman4]

Front Coming on Thursday?

[srainhoutx]

One last tough day in this very active late May Severe Weather episode before things calm down for much of the Nation. I quickly want to mention that this severe weather multi day event is what one would expect with a very chilly Western trough colliding with summertime warmth and humidity associated with the SE Ridge. The battle of different airmasses result in what we have seen over the last 10 days or so. The pattern now slowly shifts to that of Ridge of High Pressure across the Plains and a deep Eastern United States trough. We will discuss that in our June thread in the days ahead.

Today, a slow moving frontal boundary is situated from near Midland/Odessa on NE. Strong to Severe thunderstorms are firing and the beginning of a large thunderstorm complex appears to be developing and expanding toward North Texas. The Storm Prediction Center has outlined an Enhanced Risk for Severe Storms in the Dallas/Ft Worth area. A Slight Risk extend into the Austin area with a Marginal Risk into College Station.

There is a new Tornado/Severe Thunderstorm Watch likely in the next hour or so for portions of N Texas and S Central Oklahoma, so another active weather day is ahead a bit closer to home.

Regarding our sensible weather closer to home, there remains a lot of uncertainty as to where that boundary will eventually stall tomorrow morning. Some of the models stall that boundary near a Brenham to Madisonville on NE to near Lake Livingston. Some of the shorter range mesoscale models are a bit more aggressive with a SE push of that boundary into the I-10 Corridor Thursday afternoon. Anytime there are cold pools, outflow boundaries and weak frontal boundaries in and near our area in late May, it raises an eyebrow and is worth monitoring. While we DO NOT expected any severe weather here in SE Texas, slow moving thunderstorms in a weak flow suggest heavy rainfall could be an issue where those thunderstorms do develop and perhaps attempt to train. Some locations could see very little in the way of rainfall while others could see 3 to 4 inches. Mesoscale features that cannot be determined beyond 6 hours or so will likely be the driver over the next 48 hours or so. Below is the 06Z 3km NAM and it's just one example of what we may see heading into tomorrow morning.

[tireman4]

000
FXUS64 KHGX 291720
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1220 PM CDT Wed May 29 2019

.AVIATION...
A tight pressure gradient will foster moderate S-SE winds and
will maintain gusts for most of the TAF sites this afternoon.
A corridor of deeper moisture over the western half of the CWA
coupled with heating will produce some showers over the western
TAF sites. A weak boundary over N TX will sink south tonight
into early Thursday. SHRA/TSRA will develop along the weak
boundary. VFR conditions expected this afternoon into tonight
with a mix of VFR/MVFR ceilings overnight. 43

[unome]

I would love the rain they are getting the the Dallas-Fort Worth area, but not the tornado warnings

https://twitter.com/NWSFortWorth

[Cpv17]

Looks like Canton took a pretty good hit. I swear that place is a tornado magnet.

[Cpv17]

This is encouraging:

[jasons2k]

Area Forecast Discussion
National Weather Service Houston/Galveston TX
620 PM CDT Wed May 29 2019

.AVIATION [00Z TAF Issuance]...

Extremely complex forecast ahead for the area. Here is a brief
sketch of what may lie ahead - I expect that tweaks, potentially
even wholesale changes may be needed in future issuances.

Overnight: a line of strong to severe storms will weaken as it
slowly drops towards Southeast Texas. Sketch out a period of VCTS
at CLL and UTS overnight as to when storms - if any - are expected
to arrive. Very conditional threat here, and there may be no
storms at all.

Tomorrow: a cold front drops into the area. Separated from the
best forcing, there is not a lot of confidence in timing or
strength. General idea tonight is that the front will push through
the northern third to half of the area fairly well this morning,
then slow as it nears IAH. It should stall out, and I end the
forecast period with things in the general vicinity of the Houston
terminals. Use PROB30s for now to highlight most likely windows at
this time.

LBX and GLS: Despite the complexity elsewhere, these TAFs are
fairly straightforward as I stall out the front before reaching
here. If the front pushes more towards the coast, more than a
simple VCTS window may be needed.

[Katdaddy]

A line of showers and thunderstorms are slowly drifting into N portions of SE TX ahead of a weak cool front this morning. These storms should weakened as they approach the Houston area. Expect some streamer showers to move inland along the Upper TX Coast today. The cool front will stall across central portions of SE TX and then drift northward.

[jasons2k]

“Showers and thunderstorms likely, mainly after 4pm”

They may need to update that...

[srainhoutx]

Radar estimates suggest 1 to 2 inch per hour rainfall rates in the heavier showers/storms. It looks like 3 inches so far are common near Brenham with these very slow moving cells. Further West near Lockart, EWX issued a Flash Flood Warning where over 4 inches had fallen earlier.

[tireman4]

Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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878
FXUS64 KHGX 301237
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
737 AM CDT Thu May 30 2019

.UPDATE...

Line of storms holding together but looks to be slowing. Have sent
a quick update to raise chances along and south of the front
throughout the remainder of the day. Rainfall rates of 1-2 inches
possible. Most of the short term guidance allows this convection
to push down into the coastal counties...not that confident of it
getting offshore so will taper POPS down abruptly near the coast.
45

&&

.Previous Discussion...
512 AM CDT THU MAY 30 2019

.SHORT TERM [Today through Friday]...
Outflow boundary drifted out ahead of the weak cold front during
the evening but it appears the cold front (okay cool front)
starting to sag further south and nearing Burleson county...with
the outflow boundary about 20-30 miles further southeast of the
frontal boundary. Showers and 2 or 3 thunderstorms still rumbling
along the outflow boundary and impacting the CLL/UTS terminals for
a few more hours. The trend should be for the storms to wane in
strength but will probably see a few more showers develop near the
boundary. Down near the coast and coming in off the coastal waters
are widely scattered WAA showers. These too will likely continue
to develop and drift inland though a weakening trend is possible
after 6 am. Much of the area covered with multiple layers of
clouds with a narrow band of just partly cloudy/scattered clouds
from near Edna to Wharton to Hobby. The outflow boundary and front
should shift east and southeast throughout the morning with weak
to nil CAA and but with PW of 1.8 to 2" pooled near the boundary.
Daytime heating should be the main catalyst with limited upper
level support and the upper jet. The warm nose between 850-700
erodes over the area and afternoon heating should be sufficient.
Convective temperatures 85-86 should be all it takes.
Linear/veering wind profiles with low wind speeds should lead to
slow moving storms with outflow steering late morning through the
afternoon hours. Greatest rain chances should be in a wide swath
from Columbus to Tomball to Livingston. Very isolated rainfall
bullseyes of 1-3 inches with many receiving far less. Early
evening storms weaken quickly and may even have a few hours free
of showers. Wind profiles back as front stalls then starts
drifting back northward and the focus for rains shifts northward
into the northern counties early Friday morning through the
afternoon. Will need to watch for possible development with a s/w
moving across the Hill country as this could develop into a
cluster of storms but timing and location may focus this further
west of the area Friday morning but stay tuned. During the day
Friday will probably see the greater coverage (again daytime
heating driven) over the north and then for a weak seabreeze to
develop.

Temperatures although down a degree or two on the highs will still
be above normal overnight and more so to the south of the
boundary. Don`t anticipate any more record high minimum
temperatures though.
45


.LONG TERM [Friday Night Through Thursday]...

Despite the upper ridge starting to build into SE TX from the east,
we could still see some very isolated afternoon development across
northern portions of the FA on Sat (via the weakening front moving
back north) and along the coast on Sun (via the seabreeze). But we
should be drying out by Mon as this ridge settles more firmly over
the area. Daytime highs are expected to respond accordingly...with
max temperatures ranging in the lower to mid 90s (inland).

A series of strong shortwaves moving east (from around the base of
the upper trof out west) will be helping to flatten the ridge over
the region by mid week. Have re-introduced scattered POPs starting
Weds/Thurs as the upper low tracks east across the Southern Plains.
41


.AVIATION [12Z TAF Issuance]...
Mix of VFR/MVFR early this morning then transitioning to mixed
layers between 3000-7000ft. Band of showers and a few thunderstorm
along the outflow boundary should drift into the region bringing
MVFR ceilings/visibility with the heavier rainfall. Locally lower
with any showers/thunderstorms with 1700-2300z the main window
for the Metro hubs. Light winds becoming outflow driven this
afternoon. MVFR ceilings developing again 03z-08z. Showers and
thunderstorms possible overnight but confidence is low enough that
may only stretch and mention VCSH.
45


.MARINE

Scattered WAA-type showers developing across the coastal waters are
expected to persist through late this morning. This moderate/strong
SE flow should be decreasing by the afternoon as a weak front moves
into SE TX. That being said, have kept SCEC flags in place over the
offshore waters through this afternoon given the current trends. As
high pressure builds into the area (from the north central Gulf) we
should see mainly light/moderate onshore winds through the weekend.
41

.CLIMATE...

Tied the long standing record high minimum at College station
yesterday at 77 degrees...previously 1947.

New record high minimum of 79 set at Hobby yesterday beating the
previous record of 77 degrees set in 1996.

&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL) 86 72 86 72 91 / 40 20 40 20 20
Houston (IAH) 90 75 90 74 92 / 70 20 40 20 10
Galveston (GLS) 86 80 86 78 87 / 50 20 10 10 10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...None.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 5 PM CDT 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.


&&

$$

UPDATE...45/41

[Cromagnum]

Those cells look to be falling apart. Won't be surprised if I get absolutely nothing at my house.

[srainhoutx]

NWS Houston‏Verified account @NWSHouston · 3m3 minutes ago

Here are the rainfall reports over the past 12 hours: https://bit.ly/2Kg5PYT

A few highlights:
- 4.05" in Somerville
- 2.25" in Navasota
- 1.48" in North Zulch

[BlueJay]

We got some of that lovely rain this morning. The temperature fell to a comfy 68F.