JUNE 2018: Drying Trend & Summer Heat Returns

[unome]

the bigger picture - what did we do without this satellite ?

night http://weather.cod.edu/satrad/exper/?pa ... colorbars=

day http://weather.cod.edu/satrad/exper/?pa ... colorbars=

ir color http://weather.cod.edu/satrad/exper/?pa ... colorbars=

[unome]

Area Forecast Discussion
National Weather Service Houston/Galveston TX
643 AM CDT Sun Jun 17 2018

.AVIATION...

Not many big changes in this cycle of TAFs. Expectations continue to be for a gradual degradation of conditions. Went a little more optimistic than guidance and trended towards inherited TAFs for the onset of MVFR ceilings, given current appearance on satellite. Only exception here may be for the Houston metro terminals, as there is a patch of thicker cloud here early this morning.

Continue to advertise showers and storms today to be more like an active, typical summer day, and may see shower activity wane some this evening. Focus more on late tonight and tomorrow as the timeframe for more sustained showers tied to the incoming tropical wave. Have not tried to commit too hard to specifics, but instead paint a broad picture of breezy SE winds, MVFR ceilings, and numerous showers and storms that later shifts can flesh out with more specifics.

Luchs

NHC keeping Gulf distrbance at 20/20 in 8AM, still awaiting Discussion: https://www.nhc.noaa.gov/text/MIATWDAT.shtml

[don]

Im getting more concerned about Heavy rain, some of the mesoscale models look pretty aggressive with rainfall amounts.

[cperk]

Man that is one giant blob of thunder storms in the GOM.

[Rip76]

Yes it is.

[FreeportTX35]

I hope it doesn't flood in downtown..i work evenings 2:30 till 10:30 on navigation blvd..how bad is that area known to flood?

[DoctorMu]

The "blob" and sea breeze showers are still hitting some shear, so for today we'll see moderately fast moving scattered tropical showers. Tops are still getting knocked off.

[Cromagnum]

Bring it on. I'm tired of dragging the sprinklers around.

[srainhoutx]

Sunday morning briefing from Jeff: (...sorry for being late getting this posted...been tied up all morning...)

Heavy rainfall possible this evening through Tuesday

Much talked about tropical wave is moving into the western Gulf of Mexico this morning with new flare-ups of deep convection roughly 150 miles ESE of Galveston and over the Bay of Campeche. Satellite derived products and AM soundings from Lake Charles and Corpus Christi indicate that the surge of deep tropical moisture has arrived into the area with PWS of 2.0-2.2 inches south of I-10 and expanding northward. Satellite products show a pool of 2.3-2.6 inches PWS roughly 200 miles SE of the upper TX coast moving toward the NW and this extremely moist air mass will arrive late this afternoon into tonight.

Today:
Scattered tropical showers are already ongoing over the area and once temperatures reach the mid 80’s numerous showers and thunderstorms will develop. Rainfall today should average around .50 of an inch with higher amounts of 1-3 inches under the heavier storms or any storms to may train.

Tonight:
High resolution guidance has a weak signal that is showing up that low level speed convergence will become established near the coast into Galveston Bay as a 30kt low level jet develops over the region of offshore winds of 20-30mph slow to near 10-15 inland of the coast. This will likely help focus lift along the coast starting early this evening and increasing into the overnight hours…especially between midnight and 800am Monday. This appears to be a time period where sustained training or banding of rainfall may occur and thee has been a slight favoring in the short term guidance of the Galveston Bay/I-45 corridor for development. Given the setup…will focus the heavy rains tonight along the coast and into the Galveston Bay area including at least the SE half of Harris County. These trends will need to be monitor throughout the day and into this evening for indications where any training bands may set up tonight.

Monday:
Moisture influx will remain aimed at SE TX with widespread numerous showers and thunderstorms. Much of what transpires on Monday will be a result of how things evolve tonight over the coastal areas…so confidence is lower on where any particular areas could see heavy rainfall on Monday. Air mass will remain very moist and little if no heating will be required to get showers and thunderstorms going.

Monday night-Tuesday:
Moist air mass remains in place over the region with PWS running 2.3-2.5 inches. Will need to focus on Tuesday morning again for potential for coastal speed convergence erupting numerous showers and thunderstorms. This time period may focus the higher rainfall totals closer to Matagorda Bay based on overall moisture transport shifting slowly WSW with time, but cannot rule out additional heavy rainfall across any areas S of I-10.

Rainfall Amounts:
Storm totals today-Tuesday will average 1-3 inches N of I-10 and 3-6 inches S of I-10 with isolated higher amounts of 6-9 inches possible. Higher total will likely focus closer to the coast and near Matagorda Bay and in any areas of sustained cell training. Unidirectional ESE/SE flow through several thousand feet of the air mass support banding and training of cells across the area for the next 24-72 hours. Additionally, with a nearly saturated sounding profile and the tropical nature of the air mass…excessive short duration rainfall rates of 2-3 inches per hour will be possible.

Note: Excessive rainfall of 10-15 inches may focus near the coastal bend/south TX Monday-Wednesday resulting in significant flooding threat.

Hydro:
Creeks and bayous remain near average or below average flow conditions due to the recent dryness and expect the majority of the rainfall to be able to be handled as long as it is spread out over time. Concern will be for those intense short duration downpours which will result in rapid run-off and rises on area watersheds. Grounds will also gradually saturate throughout tonight and into Monday and this will result in increasing run-off over time. Main concern continues to be street flooding versus bayou flooding.

Marine:
Offshore buoys showing long period swells of 7 second arriving into the coastal waters this morning and will landfall on the coast this afternoon. ET surge continues to indicate total water level from wave and tidal run-up reaching 2.5-3.5 feet this afternoon into Monday at high tide. This may cause minor coastal flooding at times of high tide along the Gulf facing beaches on Bolivar. Run-up is already occurring along middle TX coast along Mustang Island.

Forecast 5-Day Rainfall Totals:

[/i]

[Ptarmigan]

https://weather.us/model-charts/euro/te ... 0000z.html

The EURO forecasts up to 28 inches of rain. The GFS forecasts up to 8 inches of rain. The Canadian forecasts up to 16 inches of rain.

ICON
https://www.tropicaltidbits.com/analysi ... 712&fh=168

The ICON forecasts up to 12 inches of rain.

[ticka1]

that map shows rain all south of us.

[DoctorMu]

Bring it on. I'm tired of dragging the sprinklers around.

I ran the sprinklers half-time last night just to troll the incoming storms. If I had not run them at all, that risks a complete miss by the sea breeze!

[Rip76]

that map shows rain all south of us.

Yep

[DoctorMu]

Welcome waves of liquid gold.




The bands are moving WNW from the east, rolling in from Beaumont. More rain bands N if I-10 than expected.

[davidiowx]

that map shows rain all south of us.

It has been (the Euro) shifting those higher totals further north, at a consistent rate, pover the past few days..

[Cromagnum]

that map shows rain all south of us.

Yep

Yep. If we only get 1-2 inches, this is a huge bust for us. I know South Texas needs the rain more, but would prefer we all got 4-5 inches as opposed to the sharp gradient I'm seeing.

[DoctorMu]

000
FXUS64 KHGX 171739
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1239 PM CDT Sun Jun 17 2018

.AVIATION...
Satellite/radar imagery this afternoon indicates scattered showers
and a few tstms will continue developing over sern TX today on
periphery of larger tropical wave evolving out of the western Gulf
of Mexico. These storms will continue to bring episodic lower
flight conditions across most terminals for the remainder of the
day, with conditions fluctuating between VFR and MVFR for the most
part. However, could expect even brief IFR vsby in the heaviest
rain cores. Will attempt to capture this in the TAFS the best we
can. Otherwise, look for generally deteriorating conditions
through tonight and especially tomorrow as primary
moisture/impacts of tropical wave finally get more entrenched over
sern TX with widespread MVFR and possibly some IFR Monday.

Evans

&&

.PREV DISCUSSION... /ISSUED 1007 AM CDT Sun Jun 17 2018/

DISCUSSION...
Higher precipitable water values have moved onshore and will continue
to spread inland today with increasing shower activity (isolated thunderstorm
will be possible too). With the increase in cloud cover and rain, this
might be the first day in a while with high temperatures mostly under
90 degrees (last time for College Station and Galveston was June 4th,
Houston Intercontinental Airport was May 23rd and Houston Hobby Airport
was May 25th).

Tonight and tomorrow now looks like the beginning focus for possible
locally heavy rainfall as precipitable water values approach a very
high 2.50 inches), and this pattern could potentially persist across
parts of Southeast Texas on into Tuesday.

Overnight forecast discussions below describe well how this event might
pan out over the next several days, and not much has been changed in
this thinking for the morning update. 42

[srainhoutx]

The 17Z HRRR seems to have captures the banding features as wave of heavy showers and storms move ESE to WNW across our Region. The HRRR suggests some totals of generally 1 to 3 inches with some isolated totals a little over 5 inches over the course of the next 18 hours.

[don]

12z Euro shifted the bulk of heavy rains even further north, now it shows the bulk of heaviest rains in the Coastal Bend region and Southeast Texas....

[davidiowx]

Was just about to post that don. Getting a little more interesting around here..