September 2016 - Cool & Drier To End Month

[worrybug]

Uh, should I start living up to my name?

While it may look intriguing, not every low in the water is going to become tropical.

Think again, StormOne.

[Skyguy]

Well, at least THIS run, the CMC has a weaker storm going into NOLA. It'd been depicting some pretty gruesome powerhouses on previous runs.

[srainhoutx]

Will need to watch for the potential of heavy rainfall and some stronger storms with cloud to ground lightning this afternoon, particularly for those planning on attending the College Football games this afternoon. We here in NW Harris County had a lot of lightning and brief heavy rainfall late yesterday afternoon, and that possibility exists again today, so stay weather aware if you have outdoor activities planned.

Rich tropical moisture looks to increase off the Gulf tomorrow and particularly on Labor Day as a return flow becomes established and slow moving thunderstorms could develop almost anytime with very low convective temperatures and PW's near 2.4 inches which is unusually high for early September. Stronger storms may be capable of dropping a quick 1 to 2 inches per hour with possibly some isolate higher amounts in the strongest of storms on Labor Day.

[Ptarmigan]

August 2016. Most of the wettest August had a tropical system involved with the exception of 1900, 1974 (College Station), and 2007. Galveston and Hobby Airport did not have west August. August 1900 was one of the wettest for Houston. In September 1900, the Great Galveston Hurricane made landfall. August 1900 did not have any tropical system.

Houston
http://www.srh.noaa.gov/hgx/?n=climate_iah_top10_aug

Hobby Airport
http://www.srh.noaa.gov/hgx/?n=climate_hou_top10_aug

College Station
http://www.srh.noaa.gov/hgx/?n=climate_cll_top10_aug

Galveston
http://www.srh.noaa.gov/hgx/?n=climate_gls_top10_aug

1. That doesn't necessarily guarantee a storm landfall in Houston, Ptarmigan.

2. As I suspected. The CMC has begun an eastward shift. Take a look.

Food for thought.

[srainhoutx]

Saturday afternoon briefing from Jeff:

Factors appear to be coming together to produce heavy rainfall on Labor Day.

Weak frontal boundary noted by dry air mass NE of a College Station to Wharton line today will retreat NNE as Gulf moisture surges back into the region on Sunday. Scattered showers and thunderstorms will be possible on Sunday as moisture deepens and moves inland. Much better rain chances will be possible on Monday as the current band of deep tropical moisture over the central Gulf of Mexico tracks NW into the TX coast. Waves of showers and thunderstorms will be possible from early Monday morning through much of the day. While storm motions should be on the order of 10-15mph, saturated profile will support very heavy rainfall rates of 1-3 inches per hour in the stronger storms.

Main threat will be potential street flooding and ponding where the heaviest rains fall.

92L:
Tropical wave 450 miles east of the Lesser Antilles this afternoon will continue to move westward at 15-20mph over the next several days and into the Caribbean Sea. Upper level and surrounding conditions are not expected to be all that favorable for development given dry air and various degrees of wind shear. As the system reaches the western Caribbean Sea by late next week conditions could become more favorable for some sort of tropical development assuming the wave survives the hostile conditions in the eastern Caribbean Sea.

[Katdaddy]

FLOOD ADVISORY
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
340 PM CDT SAT SEP 3 2016

TXC481-032145-
/O.NEW.KHGX.FA.Y.0191.160903T2040Z-160903T2145Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WHARTON TX-
340 PM CDT SAT SEP 3 2016

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* FLOOD ADVISORY FOR...
SOUTHWESTERN WHARTON COUNTY IN SOUTHEASTERN TEXAS...

* UNTIL 445 PM CDT.

* AT 340 PM CDT...DOPPLER RADAR INDICATED HEAVY RAIN DUE TO
THUNDERSTORMS. THIS WILL CAUSE MINOR FLOODING IN THE ADVISORY AREA.
UP TO TWO INCHES OF RAIN HAVE ALREADY FALLEN WITH ANOTHER INCH
POSSIBLE.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
LOUISE.

LAT...LON 2931 9626 2908 9636 2912 9646 2929 9648

[jasons2k]

It smells like a paper mill outside this morning; reminds me of Savannah. Must be blowing in from somewhere in East Texas or LA.

[srainhoutx]

On this date in SE Texas Weather History:

09042016 HGX 1973 Delia CrhCsKoUEAIET_z.jpg

NWS Houston ‏@NWSHouston · 1h1 hour ago
On this day in weather history... #houwx #txwx

[Katdaddy]

TS Delia 1973 was my first tropical experience at the young age of 5. A beautiful SE TX morning with nice tropical skies in League City. Rain chances increase today through Monday with locally heavy rains possible for Labor Day.

[Ptarmigan]

On this date in SE Texas Weather History:

09042016 HGX 1973 Delia CrhCsKoUEAIET_z.jpg

NWS Houston ‏@NWSHouston · 1h1 hour ago
On this day in weather history... #houwx #txwx

Tropical Storm Delia made two landfalls on Texas. It did a loopy loop.

Delia looks a bit like 2001 Allison.

[DoctorMu]

The sea breeze is kicking up this afternoon in Harris Co.

Large uptick in rain chances and expanded coverage for Labor Day with a moisture surge, high CAPE, and not strong ridging. With the convective temp bar only at 86°F - 88°F, expect a few holiday fireworks...except for us Ags who don't have the day off.








FXUS64 KHGX 041753
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1253 PM CDT Sun Sep 4 2016

.AVIATION...
Expecting more convective coverage both this afternoon and into
early Labor Day. All of the ingredients are there; increasing
moisture, early day sun warming late morning surface temperatures
into the upper 80s and weak near coastal wind convergence for
better lower level focus for scattered shower and isolated
thunderstorm development. As of the bottom of the noon hour,
fairly quiet on the radar with towering cumulus across the coastal
counties moving inland and scattered showers moving in from the
nearshore Gulf waters. Similar early evening conditions with a
scattering out of low-mid layer clouds, rural MVFR haze/fog
formation as early as late tonight (especially if area receives
late afternoon rain). Labor day morning is forecast to have a
larger areal coverage of primarily showers, transitioning to more
inland clusters of storms during the afternoon. 31

&&

.PREV DISCUSSION... /ISSUED /

DISCUSSION...
The 1200Z sounding at LCH showed a convective temperature of 88 degrees,
and at CRP 86 degrees. This temperature has already been reached
along the coast, resulting in a few showers that are moving
inland. 1200Z soundings support high temperatures between 90 and
92 degrees inland, and in the upper 80s on the coast.

Observational data is already indicating low-level directional and
speed convergence, hugging the coastline. Short term model
guidance from the HRRR and RAP suggests that this convergence zone
will stay anchored to the coast. However, some uncertainty with
regards to this solution as potential outflow boundaries may
result in a propagation of these showers and thunderstorm pushing
more inland into the early afternoon.

Sky grids have been adjusted to match current conditions, otherwise,
the forecast is on track. We will be monitoring trends, if short
term guidance is correct slightly higher POPs may be needed along
the coast for this afternoon. 8/43


ISSUED 430 AM CDT Sun Sep 4 2016/

DISCUSSION...
As expected somewhat drier air did filter into SE Texas yesterday
and remains in place this morning. Low temperatures should bottom
out in the low/mid 70s this morning but higher moisture just along
the coast will keep temperatures in the upper 70s. Radar shows
showers developing in the offshore waters of the Upper Texas Coast
and this activity should mark the leading edge of higher moisture
in the Gulf.

Upper air analysis shows a long wave trough over the west coast
with a ridge developing from the lower Mississippi River valley
through the Great Lakes. Troughing was located over the Mid-
Atlantic associated with post tropical cyclone Hermine. Hermine
should continue to meander off the Atlantic coast the next few
days before moving northeast Wednesday through Friday.

Blended precipitable water product does show more than 2 inches of
PW just off the coast and likely where current shower activity is
developing. Models show this moisture advecting into SE Texas
later today and decided to increase PoPs to 50 percent in the
afternoon with this surge in moisture. Precipitable water values
increase to around 2.2-2.3 inches on Monday and increase PoPs to
60 given model consistency for the last few days. Models still
show upper level ridging building over the lower Mississippi River
valley but the ridge may only restrict thunderstorm coverage from
wide spread to scattered. Even with scattered activity, most of SE
Texas should get meaningful rainfall. Most of the area can expect
0.25 to 0.5 inches of rain but some of these stronger storms could
still produce 1-2 inches of rain in an hour. Isolated 1-3 inch
amounts will be possible and could contribute to minor street
flooding or rapid rises on area bayous. Atmosphere will be more
than capable of high rain rates given CAPE around 2000-3000 J/kg
and the high moisture content.

After Monday the forecast remains on track with isolated to widely
scattered showers and thunderstorms each day. Precipitable water
values linger around 1.9 to 2 inches through the rest of the week
and should support at least a small chance of rain. The upper
level ridge does build Tuesday into Wednesday but then weakens
ever so slightly for the end of the week. Max temperatures should
top out in the low/mid 90s for the end of the week but will
largely depend on coverage of clouds/precip.

In the far extended the ECMWF does bring a cold front into the
area for Saturday while the GFS stalls this front north of the
area. Both models bring a stronger front into the area the
following Tuesday at 228hrs. Upper level pattern seems supportive
of a front with a trough pushing across the Great Lakes. 39

[BlueJay]

We are currently enjoying a light shower. It's lovely to sit and watch and listen

[srainhoutx]

Who's ready for our first taste of Fall like weather? The GFS and ECMWF schemes are suggesting that first shot of cooler and drier air may be headed our way around mid September. It's almost stoke those backyard fire rings with wood and enjoy overnight temperatures in the upper 50's...

[DoctorMu]

Sea breeze appears to be on vitamins this early Labor Day afternoon. Hoping for some liquid gold in CLL.

[Texaspirate11]

Sea breeze appears to be on vitamins this early Labor Day afternoon. Hoping for some liquid gold in CLL.

Beautiful by the Bay. Nary a drop.

[DoctorMu]

Sea breeze appears to be on vitamins this early Labor Day afternoon. Hoping for some liquid gold in CLL.

Beautiful by the Bay. Nary a drop.

We have a lot of near misses since the mid-August deluge. Could used a small soaker.


That's Texas weather.

[worrybug]

The sea breeze is kicking up this afternoon in Harris Co.

Large uptick in rain chances and expanded coverage for Labor Day with a moisture surge, high CAPE, and not strong ridging. With the convective temp bar only at 86°F - 88°F, expect a few holiday fireworks...except for us Ags who don't have the day off.








FXUS64 KHGX 041753
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1253 PM CDT Sun Sep 4 2016

.AVIATION...
Expecting more convective coverage both this afternoon and into
early Labor Day. All of the ingredients are there; increasing
moisture, early day sun warming late morning surface temperatures
into the upper 80s and weak near coastal wind convergence for
better lower level focus for scattered shower and isolated
thunderstorm development. As of the bottom of the noon hour,
fairly quiet on the radar with towering cumulus across the coastal
counties moving inland and scattered showers moving in from the
nearshore Gulf waters. Similar early evening conditions with a
scattering out of low-mid layer clouds, rural MVFR haze/fog
formation as early as late tonight (especially if area receives
late afternoon rain). Labor day morning is forecast to have a
larger areal coverage of primarily showers, transitioning to more
inland clusters of storms during the afternoon. 31

&&

.PREV DISCUSSION... /ISSUED /

DISCUSSION...
The 1200Z sounding at LCH showed a convective temperature of 88 degrees,
and at CRP 86 degrees. This temperature has already been reached
along the coast, resulting in a few showers that are moving
inland. 1200Z soundings support high temperatures between 90 and
92 degrees inland, and in the upper 80s on the coast.

Observational data is already indicating low-level directional and
speed convergence, hugging the coastline. Short term model
guidance from the HRRR and RAP suggests that this convergence zone
will stay anchored to the coast. However, some uncertainty with
regards to this solution as potential outflow boundaries may
result in a propagation of these showers and thunderstorm pushing
more inland into the early afternoon.

Sky grids have been adjusted to match current conditions, otherwise,
the forecast is on track. We will be monitoring trends, if short
term guidance is correct slightly higher POPs may be needed along
the coast for this afternoon. 8/43


ISSUED 430 AM CDT Sun Sep 4 2016/

DISCUSSION...
As expected somewhat drier air did filter into SE Texas yesterday
and remains in place this morning. Low temperatures should bottom
out in the low/mid 70s this morning but higher moisture just along
the coast will keep temperatures in the upper 70s. Radar shows
showers developing in the offshore waters of the Upper Texas Coast
and this activity should mark the leading edge of higher moisture
in the Gulf.

Upper air analysis shows a long wave trough over the west coast
with a ridge developing from the lower Mississippi River valley
through the Great Lakes. Troughing was located over the Mid-
Atlantic associated with post tropical cyclone Hermine. Hermine
should continue to meander off the Atlantic coast the next few
days before moving northeast Wednesday through Friday.

Blended precipitable water product does show more than 2 inches of
PW just off the coast and likely where current shower activity is
developing. Models show this moisture advecting into SE Texas
later today and decided to increase PoPs to 50 percent in the
afternoon with this surge in moisture. Precipitable water values
increase to around 2.2-2.3 inches on Monday and increase PoPs to
60 given model consistency for the last few days. Models still
show upper level ridging building over the lower Mississippi River
valley but the ridge may only restrict thunderstorm coverage from
wide spread to scattered. Even with scattered activity, most of SE
Texas should get meaningful rainfall. Most of the area can expect
0.25 to 0.5 inches of rain but some of these stronger storms could
still produce 1-2 inches of rain in an hour. Isolated 1-3 inch
amounts will be possible and could contribute to minor street
flooding or rapid rises on area bayous. Atmosphere will be more
than capable of high rain rates given CAPE around 2000-3000 J/kg
and the high moisture content.

After Monday the forecast remains on track with isolated to widely
scattered showers and thunderstorms each day. Precipitable water
values linger around 1.9 to 2 inches through the rest of the week
and should support at least a small chance of rain. The upper
level ridge does build Tuesday into Wednesday but then weakens
ever so slightly for the end of the week. Max temperatures should
top out in the low/mid 90s for the end of the week but will
largely depend on coverage of clouds/precip.

In the far extended the ECMWF does bring a cold front into the
area for Saturday while the GFS stalls this front north of the
area. Both models bring a stronger front into the area the
following Tuesday at 228hrs. Upper level pattern seems supportive
of a front with a trough pushing across the Great Lakes. 39

Will this have any bearing on where (in Texas, unfortunately) Invest 92L ends up making landfall?

[jasons2k]

It's good to see more and more meteorologists talking openly about the meteorological seasons vs. the astronomical seasons:

DISCUSSION...
Forecast appears to be relatively low impact through the week, but
there are plenty of subtle details to bedevil any meteorologist`s
inner perfectionist. The primary focus of uncertainty will be for
the extent of isolated to scattered shower and storm coverage.
It may be worth noting that with high temperatures forecast to be
near or slightly above normal under a subsident pattern aloft,
and with somewhat above normal lows implying greater surface
moisture, heat indices may be a bit reminiscent of summer. Not
seeing potential for dangerous heat for most, but a gentle
reminder that the atmosphere cares not for distinctions like
"meteorological fall" or "Labor Day ends summer".

[tireman4]

The last part makes my ears perk up....

Friday and beyond...
Weak subtropical ridging aloft looks to remain the main feature
directly over our area for the weekend into next week, but that`s
not to say there is nothing interesting that could impact our
weather in the longer term. Of most intrigue are two upper level
troughs sweeping through the northern stream that look to bring
associated surface fronts near, or perhaps even into our area. The
first will have to be particularly watched for interaction with
the remnants of current Hurricane Newton. This could result in
some significant rainfall for the Desert Southwest up towards the
TX Panhandle and Western Oklahoma. But, will there also be
potential for a deeper push of the cold front? Tonight`s model
runs say no, but can see that as a feature to watch.

The next trough looks to come in the early to middle portions of
next week. In previous nights, it has been quite strong, easily
pushing a cold front through our area. Tonight has backed off some
on that thought, with both the GFS and Euro bringing through a
considerably more blunted trough and a front that may or may not
cross into our area. Fortunately plenty of time for this to work
itself out, but it would not be a surprise to finally get a front
to work through, as it is climatologically about the right time to
be seeing the first significant front of the season.

[srainhoutx]

Tuesday morning briefing from Jeff:

Typical summer pattern expected through the end of the week.

High pressure over the central Gulf coast has built into SE TX this morning and a surge of drier air over the NW Gulf of Mexico has moved inland which will result in less coverage of our daily showers and thunderstorms compared to the last few days. This upper high recedes back eastward on Wednesday as a disturbance rounds the belly of the high and slides into SE TX. This will result in an increase in daily rain chances on Wednesday (40%). After Wednesday moisture levels remain near normal and high pressure aloft weak enough to allow a daily chance of afternoon seabreeze storms into the weekend.

Pattern becomes increasingly complicated by this weekend into early next week as it is getting to be that time of year where cold front will tease the region. Additionally, moisture and energy from landfalling Hurricane Newton over Baja this morning looks to become entrained into this frontal system. Lastly, 92L, the weak tropical wave in the central Caribbean will be moving into the SE Gulf of Mexico this weekend and there may be a window for some development of this feature in there is anything left of the wave when it reaches the Gulf.

After Friday the forecast is full of uncertainty on how far southward any frontal boundary may push and what if any development of the tropical wave may occur. This will have a direct correlation on the rainfall chances this weekend into early next week. Will lean toward the wetter forecast as that has been the way to go this summer thus far and at least one of the factors impinging on the area would likely induce greater rainfall coverage.

For what it is worth a couple of the models are showing a fairly strong front around the middle of next week which would bring some cooler air into the region…if it holds…doubt it will…but those 50 degree dewpoints do sound nice.