Texas Summer 2018

[TeamPlayersBlue]

I think those rain values should be much more widespread and much higher, personally. This will be great for the state. Might help prevent any big high pressure parking itself over us in the summer. If one were to, it wouldnt last long.

[Cpv17]

Yesterday I felt pretty confident about some heavy rain totals from this approaching disturbance, but today not so much anymore. Models are trending in the wrong direction.

[wxman22]

12z Euro is pretty aggressive with rainfall totals

[Haris]

Yesterday I felt pretty confident about some heavy rain totals from this approaching disturbance, but today not so much anymore. Models are trending in the wrong direction.

GFS is . euro trended only wetter

[weatherdude1108]

I'm ready! Of course we are leaving for Michigan on Sunday to see my wife's sister for a week. Supposed to be in the upper 80s there Sunday and Monday. Nothing I'm not used to, but I was hoping highs in the 70s up there. Lows in the 60s and high 50s.
Looks like we'll leave for Michigan when the rains get going here in Texas.


000
FXUS64 KEWX 122018
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
318 PM CDT Tue Jun 12 2018

.SHORT TERM (Tonight through Wednesday Night)...
Disorganized convection forming among the remnants of an Oklahoma
complex will drift south across North Central TX this afternoon
toward Central TX where upper ridging remains strong. Models are
nearly unanimous in showing no convection to propagate into our
northern counties this evening into tonight. However, some mid level
moisture will be contributed to the area for tomorrow as broad mid to
upper level cyclonic flow develops in the mid and upper levels over
Nrn Mexico into South TX. With unidirectional onshore flow through a
deep layer of the atmosphere, the southern periphery of the upper
ridge aloft will have been effectively weakened over South Central
Texas for Wednesday with isolated sea breeze convection pushing into
the I-35 corridor. Relaxing low level pressure gradient trends
tonight into Wednesday night will lead to less evening breeziness and
potentially cooler overnight temps that could be further reduced by
convection for eastern areas Wednesday night.

&&

.LONG TERM (Thursday through Tuesday)...
Another couple days of broad and deep onshore flow pattern brings
more sea breeze activity into mainly the eastern half of South
Central TX, and the instability and enhanced pwat values expands
farther inland on Saturday.

Model consensus continues to point toward a broad area of moisture
and instability working its way from the Caribbean across parts of
Mexico into the western Gulf late this week into the weekend. A broad
and weak mid-to-upper level low that takes shape over the western
Gulf Wednesday is shown to hold in place through this weekend as
broad area of low to mid level instability moves across Srn Mexico
into the Gulf. Models continue to show poor environmental conditions
for Gulf tropical development due to wind shear, but the NHC
remains vigilant that the models may not represent the capabilities
of the disturbance at lower levels and the potential for improving
conditions aloft by the weekend. Their forecast remains at 20 percent
over the next 5 days. The hope and reasonable expectations that
these features will remain disorganized leaves broad areas of chance
to likely categories for PoPs in the Sunday through Tuesday
timeframe. In addition to much needed rainfall, the pattern also
looks likely to lower afternoon temperatures to near or below
seasonal normals as early as Sunday.

As a reminder, please continue follow and base your medium range
planning on trusted sources, such as the National Hurricane Center,
for outlooks on potential tropical development during the hurricane
season.

&&

[Cpv17]

The latest forecast from the WPC just cut my rainfall totals in half

[bubba hotep]

GEFS has been slowly shifting west with the axis of heaviest rain. I'm thinking we see the biggest totals between I35 and the border with Louisiana, probably widespread flash flood watches at some point.

[gboudx]

Update from jeff on Tropics:

Rain chances will be increasing as moisture begins to arrive into the area from the Gulf of Mexico

Heavy rainfall will be possible Saturday-Monday

Tropical feature (91L) continues to fester in the SW Caribbean Sea with little change in organization in the last 24 hours. Surface analysis continues to show this feature as an open trough of low pressure with no defined low level circulation. Given the proximity of this feature to the land areas of central America no development is expected through the next 48 hours. Eventually this feature will move into the Bay of Campeche and southern Gulf of Mexico Friday into Saturday. Strong wind shear of 40-50kts is currently in place across the western and southwestern Gulf of Mexico and while this shear will likely weaken some as tropical storm Bud in the eastern Pacific weakens, there is forecast to remain a good bit of shear across the western Gulf into the weekend. This should prevent any sort of defined organization to the tropical wave axis and the NHC currently gives the potential for development at a low 20% through the next 5 days.

As mentioned…regardless of development…a large plume of deep tropical moisture with PWS values of 2.0-2.5 inches will be crossing the Gulf of Mexico Friday and arriving along the TX coast Saturday-Monday. This air mass will have origins in the extreme SW Caribbean Sea and also a tap of mid and high level moisture from the remains of Bud in the eastern Pacific. Expect the air mass over SE TX to saturate Saturday with numerous showers and thunderstorms spreading inland in waves from the Gulf of Mexico. There is some decent agreement in the model guidance that the “stream” of moisture will continue to be aimed at the NW Gulf coast roughly between Matagorda Bay and SW LA into Monday with bands of rainfall developing and spreading across that region. Overall the pattern looks wet starting Saturday and continuing well into next week.

Rainfall Amounts:

Global model guidance is in general agreement favoring the areas between Matagorda Bay and SW LA for the highest rainfall totals over the next 7 days, but exactly where any sort of training bands develop in the that region remains a question. The time period from Sunday into Monday may feature the greatest chance for widespread rainfall over the area, but the confidence is still not high. Widespread rainfall amounts of 2-4 inches appear possible over the region with higher isolated amounts. Those higher isolated amounts will be a result of any sustained training bands that might anchor in the very tropical air mass. This is the type of air mass that will result in intense short duration rainfall totals of 2-3 inches in an hour. One other potential to watch for in the coming days will be the idea for morning storms near the coast or just offshore to “rob” the inland flow of moisture and focus the heaviest rainfall near the coast or just offshore. These sort of very tropical air masses tend to like to focus development in the early morning hours (2-7am) near the coast. This type of pattern could result in the maximum totals close to the coast or offshore

Rainfall totals will need adjusting over the next 24-72 hours as confidence increases where the greatest moisture axis will establish and where the potential for training rainfall will be greatest.

Hydro:

Grounds across much of SE TX are dry to very dry with the lack of recent rainfall. Moderate to severe drought conditions are in place especially across the SW half of the region. Initial rainfall will likely be quickly absorbed by the dry grounds and run-off will be limited, but grounds will gradually saturate and run-off increase as the event prolongs over multiple days. Flash Flood guidance for Harris County is running about 4 inches in 1 hour up to 5.5 inches in 6 hours before significant amounts of run-off would occur. Over the region the 6-hr flash flood guidance ranges between 5.0-6.4 inches. Overall the grounds will be able to handle much of the expected rainfall as long as it does not all fall in a short period of time.

[Haris]

another day another massive model disagreement

[Cpv17]

another day another massive model disagreement

The GFS is flip flop happy. The 0z run had my area getting 6-9” and now the 12z says 1-2”

[Haris]

another day another massive model disagreement

The GFS is flip flop happy. The 0z run had my area getting 6-9” and now the 12z says 1-2”

euro shows 12" for HOU

[Cpv17]

another day another massive model disagreement

The GFS is flip flop happy. The 0z run had my area getting 6-9” and now the 12z says 1-2”

euro shows 12" for HOU

I’m an hour southwest of Houston where the drought is actually worse than it is in the Houston area.

[TeamPlayersBlue]

another day another massive model disagreement

The GFS is flip flop happy. The 0z run had my area getting 6-9” and now the 12z says 1-2”

euro shows 12" for HOU

Pic?

[Cpv17]

The GFS is flip flop happy. The 0z run had my area getting 6-9” and now the 12z says 1-2”

euro shows 12" for HOU

Pic?

I heard on the KHOU board that the euro has a swath of 10-12” east of Houston from Livingston to Liberty. A pic would work lol

[Haris]

The GFS is flip flop happy. The 0z run had my area getting 6-9” and now the 12z says 1-2”

euro shows 12" for HOU

Pic?

[wxman22]

The GFS is flip flop happy. The 0z run had my area getting 6-9” and now the 12z says 1-2”

euro shows 12" for HOU

Pic?

[Cpv17]

euro shows 12" for HOU

Pic?

Ehh that’s more like 4” for the Houston area. 12” spot is well east of Houston and only has my area getting 2” ..I’ll pass on that run.

[TeamPlayersBlue]

Oh wow, extremely localized on that map. Watching the 700 mb chart for the weekend. Should be fun!

[Haris]

EPS trended ALOT WETTER!!!

[weatherdude1108]

EWX says impressive lifting, but stubborn high making it difficult to pinpoint areas with highest QPF forecasts due to lacking lift. But it's such a large area of moist tropical air.

I'm guessing based on the origins of this tropical air mass from the Caribbean and Gulf, it would be the equivalent of a normal day in the tropical rain forest. Some areas don't get anything, other areas get torrential, waterfall-like multi-inch-per-hour rainstorms.

FFG is high because of the extended dry spell/heat, but they will have to keep an eye on it with potential repeated tropical downpours.

000
FXUS64 KEWX 131957
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
257 PM CDT Wed Jun 13 2018

.SHORT TERM (Tonight through Thursday Night)...
As of 230PM, isolated showers and thunderstorms were developing from
the San Antonio area and southwest towards Eagle Pass. GOES vis/IR
satellite was clearly showing these storm tops were having trouble
tapping into the deep instability present, likely due to a lack of
focused lifting. Area soundings show some possibilities for these
cells to produce some strong outflow, which could produce lifting
enough to allow some of these cells to mature to the point of some
small hail, but otherwise, frequent cloud to ground lightning and
some briefly heavy rain will be the main concerns this afternoon.
TTU- WRF/HRRR decreases coverage shortly after 00Z.

Tomorrow`s forecast will largely be copy/paste of today`s with
another possibility for isolated shower/storm development mid to late
morning and persisting into the afternoon hours. This will begin
again in the southeastern zones (Coastal Plains) and migrate
northeast. Again, weak shearing but ample instability should allow
for thunder and perhaps some small hail and gusty winds, but not
expecting anything to reach severe criteria at this time.

&&

.LONG TERM (Friday through Wednesday)...
Friday looks to be yet another day similar to today and Thursday, but
by the weekend, we will begin to see some significant changes to the
forecast.

The tropical disturbance in the Gulf is expected to bring a very
moist air mass into the Texas Gulf and inland to South Central Texas
overnight Saturday into Sunday morning. By Sunday morning, GFS PWAT
values of 2+" will begin spreading in from the Gulf and begin an
extended period of high moisture and elevated PoPs through at least
the middle of next week.

While there is still significant discrepancies in the H5 pattern
depicted in the mid to long range models, there is good agreement in
a very moist air mass that will require very little lifting to
produce showers and storms. The ECMWF/GFS both take Bud (in the
Pacific) and merge it with a developing trough dropping south from
the Pacific Northwest, however, the stubborn high pressure across the
Central US weakens only minorly. Thus, while a very moist airmass
with impressive low level dynamics and convergence is expected in
response to this tropical disturbance, upper level support will be
largely lacking.

This makes QPF forecasts rather difficult to pinpoint without focused
deep layer lift to zero in on. Models haven`t significantly trended
upwards with the 12Z runs vs the 00Z runs and the previous forecast`s
mention of 1-3 inches across the region from Sunday through Wednesday
still appears valid. However, the concern of isolated amounts of up
to 6 inches also seems like a prudent mention given the exceptionally
high PWAT values being shown in the GFS. Basically, even if we get
three days of afternoon isolated to scattered convection, can`t rule
out some 1-2 inch/hr rainfall rates that could repeatedly impact
unlucky localized areas..perhaps enough to result in some flooding
concerns in the most unlucky areas. That being said, FFG values right
now are indicating 1 hr values of over 3"/hr needed, which means we
will likely be able to take these values without major impacts.
However, we will need to watch these trends closely moving forward.