AUGUST 2018 - Scatterd Showers/Storms To End August

General Weather Discussions and Analysis

Re: AUGUST 2018 - Pattern Change/Wetter & Cooler WX Likely

Postby srainhoutx » Mon Aug 06, 2018 6:15 am

Radar is active inland early this morning with showers/storms just East of DT dropping a quick .5 inch. No significant changes to the forecast reasoning this morning for the rest of the work week into the weekend. Rain chances daily with increasing chances of more widespread and possibly heavy rainfall beginning Thursday across our Northern Zones slowly sagging S along a boundary Friday and at least Saturday, if not longer. The WPC 7 Day QPF chart this morning continues to increase amounts across a San Antonio/Austin/Brenham/Huntsville line. Keep a close eye on the weather trends throughout the week. It's looking unsettled!

08062018 9Z 7 Day QPF p168i.gif


From NWS HGX Forecasters Luchs and Overpeck this morning...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
404 AM CDT MON AUG 6 2018

.NEAR TERM [THROUGH TODAY]...

EARLY THIS MORNING, WE CONTINUE TO SIT ON THE EDGE OF A SURFACE
HIGH, WITH A WEAK EASTERLY WAVE REACHING THE LOWER TEXAS COAST.
ALOFT, THERE IS A WEAK MIDLEVEL TROUGH OVER THE WESTERN GULF.
ASSOCIATED WITH THAT, THERE ARE SCATTERED SHOWERS OVER THE GULF
WATERS, GENERALLY WORKING TOWARDS THE COAST.

AS ONE MIGHT EXPECT, WITH SUCH FEATURES HANGING AROUND THE
NEIGHBORHOOD, TODAY WILL HAVE A HIGHER THAN TYPICAL CHANCE FOR
SHOWERS AND THUNDERSTORMS. LOOK FOR SOMETHING THAT GENERALLY
FOLLOWS THE TYPICAL DIURNAL PATTERN, BUT STARTING EARLIER, WITH
HIGHER COVERAGE AS MORE CELLS DEVELOP, AND LINGERING PERHAPS A
LITTLE BIT DEEPER INTO THE EVENING - PERHAPS AN HOUR OR SO.

SIMILARLY, WITH ENHANCED CONVECTION TODAY, TEMPERATURES SHOULD BE
NEAR, OR MORE LIKELY, A LITTLE COOLER THAN YESTERDAY. THIS WILL
ALSO DEPEND ON TIMING OF ANY STORMS SEEN AT A PARTICULAR LOCATION.
SO, IN GENERAL, WELL INLAND HAS THE GREATEST AREA CLOSER TO
YESTERDAY'S HIGHS, WHILE THE COASTAL AREAS TEND TO BE COOLER.

LUCHS

.SHORT TERM [TONIGHT THROUGH TUESDAY]...

THOUGH THE DAY'S SHOWERS AND STORMS MAY LINGER A BIT DEEPER INTO
THE EVENING THAN USUAL, THINGS SHOULD STILL WRAP THEMSELVES UP AS
THE SUN GOES DOWN. THE UPPER VORT MAX/SUBTLE TROUGH DOESN'T LOOK
SUPER STRONG, WE'LL LOSE THE SEABREEZE AND WEAKENING STORMS WON'T
BE ABLE TO GENERATE COLD POOLS STRONG ENOUGH FOR SOLID OUTFLOW
BOUNDARIES, AND SO THINGS SHOULD STILL COME TO AN END THIS
EVENING.

TUESDAY LOOKS TO LARGELY BE A REPEAT OF TODAY. WE DON'T GET A
FULL OUT COL SETUP, BUT BETWEEN OUR AFOREMENTIONED UPPER TROUGH,
AND A TROUGH OVER THE GREAT LAKES KEEPING A BREAK IN THE
SUBTROPICAL RIDGE, ALONG WITH THE EASTERN AND WESTERN BRANCHES OF
THE RIDGE...IT'S COL ENOUGH. IN SHORT, THINGS GET HUNG UP IN OUR
AREA, AND THE NAM HINTS AT A BIT OF EXTRA VORTICITY POPPING UP
ALONG THE COAST AS A SHEAR AXIS FORMS OVERHEAD. AMUSINGLY ENOUGH,
THE NAM STAYS PRETTY DRY WHILE THE GFS AND EURO ARE MORE WET. SO,
I TAMP DOWN POPS FOR TOMORROW A LITTLE FOR UNCERTAINTY, BUT IN
GENERAL I USED TODAY AS A TEMPLATE. I THINK AS LONG AS THE
ENVIRONMENT DOESN'T CHANGE UNEXPECTEDLY ON ME TOO MUCH, WE SHOULD
SEE ANOTHER DAY WITH MORE SHOWER AND STORM ACTIVITY THAN TYPICAL.
IN HAND WITH THE LOWER POPS, HIGH TEMPS ARE SIMILAR BUT A TOUCH
WARMER THAN THE FORECAST FOR TODAY, BUT I SUSPECT THAT IF
CONFIDENCE IN INCREASING CONVECTION GOES UP, TEMPERATURES WILL
HAVE TO BE NUDGED BACK DOWN A SHADE AS WELL.

LUCHS

.LONG TERM [WEDNESDAY THROUGH MONDAY]...

LOOKING AT THE OVERALL UPPER LEVEL PATTERN AT 500MB FROM 12Z
WEDNESDAY TO 12Z SUNDAY - GEFS/GFS/ECMWF/CMC ALL HAVE FAIRLY
SIMILAR TRENDS. THIS MEANS HAVING A MEAN RIDGE THAT BUILDS OVER
THE GREAT BASIN WEDNESDAY INTO THURSDAY WITH A MEAN TROUGH FROM
THE PLAINS THROUGH THE GREAT LAKES AND NEW ENGLAND STATES. IT
STILL LOOKS LIKE A SHORT WAVE TROUGH DROPS INTO THE PLAINS
THURSDAY ALLOWING FOR LOWERING HEIGHTS THURSDAY INTO FRIDAY OVER
TEXAS. SATURDAY THE RIDGE BEGINS TO BUILD EAST TOWARDS THE
NORTHERN PLAINS WHICH THEN STRETCHES OUT THE TROUGH AXIS FROM THE
GREAT LAKES BACK THROUGH TEXAS. BEYOND 12Z SUNDAY, THE PATTERN
GETS MESSY NO MATTER WHICH MODEL YOU LOOK AT BUT THEY ALL SEEM TO
HAVE LOWER 500MB HEIGHTS OVER THE REGION.

AT THE SURFACE, SOUTHERLY WINDS WILL CONTINUE TO ALLOW FOR MOIST
CONDITIONS FOR MUCH OF THE WEEK AND THROUGH THE WEEKEND. GIVEN THE
UPPER LEVEL PATTERN, A FRONTAL BOUNDARY MAY PUSH INTO NORTHERN
PORTIONS OF THE FORECAST AREA LATE THURSDAY INTO FRIDAY. THIS MAY
DEPEND UPON COLD POOLS GENERATED BY MCSS TO RE-ENFORCE THE
BOUNDARY AND CAUSE IT TO MOVE SOUTH MORE THAN EXPECTED. THIS WILL
BE THE IMPORTANT MESOSCALE FACTOR THAT COULD AFFECT PRECIPITATION
PLACEMENT IN THE THURSDAY THROUGH FRIDAY TIME FRAME. PRECIPITABLE
WATER VALUES RANGE FROM 1.7 TO 2 INCHES THROUGH MUCH OF THE WEEK
AND WEEKEND. PW VALUES OF 2 INCHES OR MORE ARE EXPECTED TO BE
LOCATED ALONG THE FRONTAL BOUNDARY. THE COMBINATION OF THE DEEP
MOISTURE, FRONTAL BOUNDARY AND UPPER LEVEL VORTICITY MAXIMA MOVING
ACROSS NORTH TEXAS WILL SUPPORT CLUSTERS OF MCSS. THESE MCSS
COULD PRODUCE HEAVY RAINFALL AT TIMES AND IF THEY MOVE OVER SOME
OF THE SAME AREAS THAT PREVIOUSLY HAD RAINFALL, FLOODING IMPACTS
MAY BECOME AN ISSUE.

OTHER THAN HAVING CONFIDENCE IN THE OVERALL WEATHER PATTERN TO
PRODUCE HEAVY RAINFALL, THERE IS VERY LITTLE CONFIDENCE IN TIMING
AND LOCATION OF THE MCSS THAT MOVE ACROSS CENTRAL TO EAST TEXAS.
RIGHT NOW IT LOOKS LIKE HOUSTON SHOULD NOT BE IN THE PATH FOR
HEAVY RAINFALL, BUT THAT COULD CHANGE DEPENDING UPON THE BOUNDARY
AND LOCATION OF HIGHEST MOISTURE. WE ARE STILL IN A WATCH AND SEE
MODE WITH THE HEAVY RAINFALL POTENTIAL STILL AT DAY 4/5 OF THE
FORECAST. IT VERY WELL COULD BE THAT FRIDAY AND SATURDAY END UP
BEING THE DAYS WITH HIGHER THUNDERSTORM CHANCES.

Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

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Re: AUGUST 2018 - Pattern Change/Wetter & Cooler WX Likely

Postby BlueJay » Mon Aug 06, 2018 12:57 pm

We are getting a lovely after lunch shower right now! How nice.
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Re: AUGUST 2018 - Pattern Change/Wetter & Cooler WX Likely

Postby jasons » Mon Aug 06, 2018 3:08 pm

Rained hard at the office. Fizzled at the house though - a whopping .10"
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Re: AUGUST 2018 - Pattern Change/Wetter & Cooler WX Likely

Postby DoctorMu » Mon Aug 06, 2018 4:43 pm

We may have had a drop or two at the house. This time of year, we will take clouds blocking the sun in the afternoon!

20-30% chance or rain in CLL through Wednesday, then 30-50% from Thursday through Sunday.

Area Forecast Discussion
National Weather Service Houston/Galveston TX
359 PM CDT Mon Aug 6 2018

.DISCUSSION...
A typical summer day with a smattering of showers and isolated
thunderstorms. As of this writing, about 40 to near 50 percent of
the area picked up measurable rain with the highest amounts of
between a half of an inch to 1.5 inches occurring either in
Matagorda County or around the city and points just northwest of
town. Expecting a significant waning of northern CWA action
through 8 PM with loss of heating. A quiet and muggy evening
with Tuesday morning minimum temperatures falling into the middle
70s inland to around 80 F at the immediate coast.

The overall upper level pattern will undergo little change though
Friday as Texas remains under the influence of flattened southern
CONUS ridging. Relatively lower heights, or a height weakness
channel over the state, will allow for the return of widely
scattered shower/isolated storm behavior throughout the work week.
Lower column moisture over the central Gulf is modeled to be
advected in through mid week and this may lower subsequent daily
POPS to more 20 to 30 percent southeast Texas (areal) coverage.
Soon-to-be Hurricane Ileana in the East Pacific moving northwest
up the western Mexico coastline may also strip higher mid-upper
moisture away from the region as this lends itself to a more dry
than wet overall pattern through late week. Partially cloudy days
with the diurnal temperature curve remaining within a few degrees
on either side of the early August climate curve.

Change begins to take shape late in the week as a Mississippi
River Valley trough axis transitions further west-southwest into
far northeastern Texas/northern Louisiana through the weekend.
This will push a weak boundary into the Piney Woods and, with a
series of weak disturbances moving along the Red River Valley and
into a near 2 inch pwat air mass, northern third forecast area
rain chances will be on the up and up. An upper low taking shape
over western Texas will also create a more diffluent central and
eastern Texas mid to upper level environment over the weekend. If
this low remains way out west over the NM/TX line, then any
significant weather will remain over central and western Texas.
If this low meanders a touch east on Sunday, then our western CWA
convective chances will be on the rise. As of now, this forecast
calls for modest rain chances that are all dependent upon this
low`s eventual movement. 31

&&

.MARINE...
High pressure over the eastern US and lower pressure over the western
high plains will maintain an onshore flow through the first half
of next week. Beach Patrol reported strong rip currents this
morning and will continue the rip current statement today and will
re-evaluate on Tuesday. Scattered showers and thunderstorms will
persist through the week with winds and seas temporarily higher
near any stronger storms. 43

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 75 96 75 98 75 / 10 30 10 20 10
Houston (IAH) 77 93 77 94 77 / 10 50 10 40 10
Galveston (GLS) 82 89 82 91 81 / 20 50 20 40 10
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Re: AUGUST 2018 - Pattern Change/Wetter & Cooler WX Likely

Postby unome » Tue Aug 07, 2018 5:59 am

DoctorMu wrote:We may have had a drop or two at the house. This time of year, we will take clouds blocking the sun in the afternoon!

20-30% chance or rain in CLL through Wednesday, then 30-50% from Thursday through Sunday.


the clouds are most welcome & we lucked out with some rain yesterday - hoping your area gets more, it's getting dry -

https://www.harriscountyfws.org/
https://water.weather.gov/precip/
http://climatexas.tamu.edu/drought/maps/index.html
http://climate.ncsu.edu/drought/map
http://droughtmonitor.unl.edu/
https://www.drought.gov/drought/dews/southern-plains
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Re: AUGUST 2018 - Pattern Change/Wetter & Cooler WX Likely

Postby Kludge » Tue Aug 07, 2018 8:11 am

Not a drop here in far north Grimes County since July 5. Praying for relief at the end of this week... but hopes have been dashed so many times over the last 3 weeks. :? :(
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Re: AUGUST 2018 - Pattern Change/Wetter & Cooler WX Likely

Postby srainhoutx » Tue Aug 07, 2018 12:05 pm

Kludge wrote:Not a drop here in far north Grimes County since July 5. Praying for relief at the end of this week... but hopes have been dashed so many times over the last 3 weeks. :? :(


The 12Z GFS and Canadian are encouraging with where the boundary stalls across the Brazos Valley Region basically across or just S of Grimes County. I sure hope that you folks finally get in on at least a decent chance of some sorely needed rainfall. Fingers Crossed Kludge!
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

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Re: AUGUST 2018 - Pattern Change/Wetter & Cooler WX Likely

Postby jasons » Tue Aug 07, 2018 4:47 pm

...and everything blows-up to the north as soon as the sea breeze passes over me. Within a few miles. Typical. Hopefully our friends to the north are enjoying some rain...
Last Measurable Rainfall: September 26
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Re: AUGUST 2018 - Pattern Change/Wetter & Cooler WX Likely

Postby DoctorMu » Tue Aug 07, 2018 5:21 pm

srainhoutx wrote:
Kludge wrote:Not a drop here in far north Grimes County since July 5. Praying for relief at the end of this week... but hopes have been dashed so many times over the last 3 weeks. :? :(


The 12Z GFS and Canadian are encouraging with where the boundary stalls across the Brazos Valley Region basically across or just S of Grimes County. I sure hope that you folks finally get in on at least a decent chance of some sorely needed rainfall. Fingers Crossed Kludge!



Hopefully, the front and rain push past Hearne.

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Re: AUGUST 2018 - Pattern Change/Wetter & Cooler WX Likely

Postby srainhoutx » Tue Aug 07, 2018 5:59 pm

I wanted to briefly touch on some indications starting to show up in our reliable ensembles regarding the MJO as we March steadily closer to peak Hurricane Season that thankfully thus far has been inactive with the 4th named storm way out in the Atlantic named today. The Global Ensembles are hinting that a very favorable pattern may develop as August ends and September begins. Historically when the MJO enters Phase 2/3, we've seen some memorable Hurricanes such as Harvey last year, Hurricane Ike back in 2008 among others. The Updated 40 Day Outlook has been sniffing this potential Hemispheric Pattern possibly developing for several day and the ECMWF Ensembles flipped to agree with the American Ensembles today. Let this serve as a reminder that even in an inactive Hurricane Season, it only takes one to make it a bad one.

ensplume_small.gif
ensplume_small.gif (24.26 KiB) Viewed 573 times

08072018 MJO ECMF_phase_51m_small.gif
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

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