September 2016 - Cool & Drier To End Month

[texoz]

Looks like small meso system just west of San Antonio this morning? Any thoughts on that?

[DoctorMu]

Looks like small meso system just west of San Antonio this morning? Any thoughts on that?

Yep. Streamer showers in SE Texas ahead of that Meso-mess heading toward the Hill Country.

While there may be more rain associated with the front tomorrow, the Meso could head toward Fort Bend area?? later today.






A beautiful week after the front.




Long range outlook: eye on 97L last next week.


Area Forecast Discussion
National Weather Service Houston/Galveston TX
1008 AM CDT Sun Sep 25 2016

.UPDATE...
Made a few tweaks to the previous forecast. Adjusted the high
temperatures down a degree or two to be more in line with latest
short term guidance. Still expecting scattered to widespread
showers and thunderstorms across SE Texas today, with the most
activity expected over the SW zones due to a plume of higher PWs
over that area. Showers and storms today may produce heavy
rainfall, and rainfall rates of around 2" per hour have already
been observed with storms this morning. Storm motion should be
sufficient enough to limit any flooding impacts to minor street
flooding, however further issues may arise if multiple storms
begin to train over the same area or storm motion slows any
further. 11

&&

.PREV DISCUSSION... /ISSUED /

AVIATION...
SHRA/TSRA activity continues to focus along the coast this
morning and timing of SHRA/TSRA near the terminals will be the
main aviation concern for the 25/12Z TAFs. Expect coverage to
focus near Galveston and Angleton through mid-morning, before
expanding inland with heating. Short-term guidance continues to
show the upper Galveston Bay focusing SHRA/TSRA activity towards
Houston IAH by late morning, but with SPC mesoanalysis showing
some weak upper lift over the region this morning coupled with
deep Gulf moisture have gone ahead and added TEMPO TSRA mentions
at all terminals. Have lower confidence on when SHRA/TSRA will end
with this weak lift in place, but expect coverage to decrease by
late afternoon to early evening. Main thunderstorm hazards will be
gusty and erratic winds and IFR TO MVFR ceiling/visibilities in
stronger cells.

Conroe and Huntsville have briefly seen IFR/LIFR ceilings this
morning and may continue to experience temporary ceiling
restrictions before low clouds lift with heating. Otherwise, VFR
conditions and east/southeast winds 10 knots or less are expected
to prevail at all terminals outside of SHRA/TSRA.

For planning purposes... a cold front with a weak north to
northeast wind shift is expected to move across the terminals
during the day on Monday, with scattered to numerous SHRA/TSRA
possible ahead of this boundary.

Huffman

PREV DISCUSSION... /ISSUED /

DISCUSSION...
Large swath of showers and thunderstorms from near Sugarland to
Palacios and out into the Gulf beyond 150nm. Ridging in the
central region of the Gulf keeping the mean flow from the SSE.
With the abundant moisture plume over the Gulf flowing into SETX this
should keep rain chances high today generally along and south of a
line from College Station to Anahuac with scattered coverage to
the north. Soundings today look conducive to rapid growth of
storms today especially during the afternoon hours with
temperatures in the mid to upper 80s yielding 2500-2800 CAPE/PW
2-2.2" with no capping to speak of over most of the
region...perhaps slight capping in the northeast counties. Storms
will be slow movers 10-15 knots and some potential for storms to
line up and traverse the same areas with redevelopment in such a
moist unstable atmosphere a good bet. Locally heavy rainfall
possible and can expect 2 to 4 inch accumulations within a short
period of time if these storms line up. Minor street flooding
possible this morning through late afternoon. With the low level
flow from the ESE-SE may see a greater chance for waterspouts
again today near the coast through at least early afternoon.
Overnight may see the outflow from the storms along and ahead of
the cold front push southeastward with the focus for storms
mainly in the west and over the Gulf overnight...streaming mainly
into the coastal counties after midnight. During the day Monday
the winds back to the northeast with the cold front dropping to
near a Crockett to Conroe to Wharton line by late afternoon/early
evening. Deeper moisture gets shunted west and pooled along and
south of the boundary. Still some instability and plenty of
moisture for scattered showers and thunderstorms Monday. May have
some heavy rain in the southwestern-most counties too. Monday
night into Tuesday morning the cold front should be along the
coast or just out into the nearshore waters pushing south during
the day on Tuesday. Drier air will expand southward with the weak
CAA and rain chances quickly taper down from north to south.
Temperatures should only reach the lower to mid 80s. Clouds will
likely linger most of the day Tuesday before clearing again from
the north to the south on Wednesday with a slow afternoon warming
trend Wednesday through Friday. Larger diurnal temperature range
thanks to the much drier air as high pressure builds in across TX.
Upper ridging axis over Mexico/TX looks to remain strong Wednesday
through Monday.

In the tropics...GFS model continues to bring tropical wave into
the Caribbean and intensifies it rapidly Tuesday the 4th through
Wednesday the 5th and now ECMWF has a much weaker system much
slower and veering off to the right skirting the Caribbean.
Caribbean would likely be a low shear environment and very warm so
conducive to development if the system gets into Caribbean. Still
in the monitor mode as this system `might` be in the central
Caribbean 10 days from now.

[DoctorMu]

Leading eastern edge the meso heading toward San Antonio - Austin area. Will watch for any continued progression east this afternoon. Heavy rain in that bowed line of storms.

[Ounce]

Yesterday, I got my first rain since September 9th. From two different storms - amazing! But alas, the curse tried to continue its grip as I got .04" the first round and .03" the second round. The ground under the tree canopy stayed completely dry. I'm optimistic for better luck over the next couple of days.

Oh, happy day!

Evidently, prosperity must be measured, so you do not get drunk on your new moisture.

[jasons2k]

I am right in the middle of a ring of fire it seems.

[srainhoutx]

Not a drop of rain here today so far. Thankfully I got the pool brushed and cleaned as well as some yard work done today. Skies are beginning to look a bit threatening though.

[unome]

Not a drop of rain here today so far. Thankfully I got the pool brushed and cleaned as well as some yard work done today. Skies are beginning to look a bit threatening though.

yup, we got a lot done here also - rained so hard yesterday the water was coming over the gutter so figured it was time to clean them out - such a fun job !

radar has a weird figure-8 look about it, it went around us earlier, but I think it will probably hit about the time we want to grill

http://weather.cod.edu/satrad/nexrad/in ... -N0Q-1-200

[DoctorMu]

Meso may be gathering over Brazos, Grimes, Walker counties. The Aggiedome appears to be finally breaking down.

Rain is light so far...

Here are a couple of kewl wall cloud pics from about 2:30 pm:

[jasons2k]

From NWS-HGX:

A cold front will bring cooler temperatures (lows in the 60s!) to parts
of our area beginning as early as Tuesday morning and continuing for
the remainder of the week. The last time we saw temperatures below 70
degrees was June 6th at College Station (69 degrees), June 5th at Houston
Intercontinental Airport (68 degrees), June 2nd at Houston Hobby Airport
(69 degrees) and May 27th at Galveston (66 degrees).

[unome]

40s in the panhandle http://www.wrh.noaa.gov/zoa/temperature.php?map=zfw

can't wait for it to get here !

[Katdaddy]

Scattered showers and thunderstorms will be possible ahead of our cool front that will move off the coast by early Tuesday morning followed by beautiful Fall weather through the weekend.

From this morning's HOU-GAL AFD:
Wednesday through Saturday should be very pleasant with lows in the mid 50s to lower 60s and highs in the 80s.

[tireman4]

00
FXUS64 KHGX 261210
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
710 AM CDT Mon Sep 26 2016

.AVIATION...
Messy forecast for the first 12 hours of the 26/12Z TAFs with a
mix of LIFR to VFR ceilings across the Southeast Texas terminals
and a weak frontal boundary moving across the region. Main
aviation concerns will be timing for these ceilings and scattered
SHRA/TSRA today both ahead and with the cold front.

Morning surface analysis shows a poorly defined cold front
stretching from South Texas into northwestern Louisiana and this
boundary will continue to move south into the Gulf through the
day. Low clouds currently impacting CLL/UTS/CXO/IAH will gradually
improve through the morning, but expect CLL/UTS to hang on to MVFR
ceilings through 18Z as low level moisture remains trapped beneath
a post-frontal inversion. Easterly low level flow ahead of this
frontal boundary has allowed some drier air over southwestern
Louisiana to move into the region, keeping the terminals rain-free
this morning. Model guidance is fairly consistent in developing
SHRA/TSRA with daytime heating today, but a fairly persistent BKN-
OVC deck around FL150 looks to keep convective temperatures (low-
mid 80s) from being reached until early to mid afternoon near the
terminals. Have pushed onset of SHRA/TSRA back a few hours as a
result, with rain continuing into the evening hours as a weak
disturbance over South Central Texas and the frontal boundary move
across the area. Concerned that coverage may be a bit overdone
with most model guidance not appearing to have a great handle on
some of the drier air that moved in from the east and have low
confidence on timing for any terminal impacts this afternoon or
if TS will actually occur near the terminals. Loss of heating as
well as forcing from the front/disturbance will result in dry
conditions through the remainder of the TAF period.

Otherwise, light east/northeasterly winds around 5 knots this
morning are expected to become northerly and increase to near 10
knots behind the cold front. May see a few MVFR ceilings develop
overnight behind the front, but confidence is not high enough to
include in the TAFs attm.

Huffman

&&

.PREV DISCUSSION... /ISSUED /

UPDATE...
Quick update to lower pops for the early morning hours.
Looks like fog has held off as well. HRRR agrees and is still
holding off on precip inland through 16z. RAP appears to generous
with precip early on so have ignored it.

45

&&

.PREV DISCUSSION... /ISSUED /

DISCUSSION...
Storms near the coast have waned and storms over the Hill Country
expanding west with mid level troughing from HOU-CLL and mid level
ridging from LFK-BPT-BYY. This is currently placing most of SETX
in weak subsidence. VWP showing SFC-8kft of E to NE winds. This
may bode poorly for rain chances this morning until we warm up
to 80-81 degrees. Have lowered pops in the short term but by 10a-
noon temperatures should be high enough and able to overcome the
subsidence with the abundant moisture in place for scattered
showers and thunderstorms to develop. Still some questions on
where storms may develop along the frontal boundary this
afternoon. At 4 am front looks to be along a line from Longview to
Waco to Junction with ridging having helped to back our winds to
the northeast and shifting low level convergence into the Gulf.
In addition lowering cigs across the north and central counties with
some light-moderate fog. The clouds will persist today given the
moisture present but the lower cigs should improve by mid morning
or so and transition over to CU and abundant high clouds so we
should struggle to get to the mid 80s.

This afternoon scattered precip develops as front sags southward
and by 3 to 6 pm should be close to the Highway 59 corridor
probably pushing offshore tonight/early Tuesday. Scattered storms
will be possible through the evening hours and may have to keep an
eye out for a cluster of storms to develop to the southwest of
Houston where heavier rains may occur. Could also see a waterspout
near the coast and some tropical funnels near the coast. The
storms should wind down tonight then possibly redevelop Tuesday
morning over the southern counties though primarily showers.
During the afternoon Tuesday some isolated thunderstorms south of
the I-10 corridor before dry air finally wins out and blankets the
region.

Wednesday through Saturday should be very pleasant with lows in
the mid 50s to lower 60s and highs in the 80s. This will bring our
long record stretch of 70 or greater temperatures at IAH to an
end. The current record stands at 112 days in a row with 106 days
set back in 1991 ending 09/18.

Guidance still keeping the tropical system to the eastern
Caribbean turning north and through day well outside of the Gulf
of Mexico and potentially along or east of the Eastern Seaboard.

45

MARINE...
Outflow from thunderstorms yesterday has served as a focus for
showers and thunderstorms early this morning, with greatest coverage
south and southwest of Matagorda Bay where the outflow intersects a
coastal trough. Expect scattered showers and thunderstorms to
continue across the coastal waters through the remainder of the day
and into the overnight hours as coastal convergence and
aforementioned boundaries (and any others from subsequent storms)
result in continued development. Stronger storms will be capable of
heavy rainfall reducing visibilities to 1 nautical mile or less at
times and locally enhanced winds/waves. Low level shear is slightly
stronger than yesterday and forecast lapse rates are not quite as
steep which will help mitigate against a greater waterspout threat,
but still cannot rule out an isolated waterspout along the coast
today with deep tropical moisture in place.

A weak front stretching from south central Texas towards the
ArkLaTex early this morning will push across Southeast Texas during
the day, reaching the coastal waters on Tuesday. Shower and
thunderstorm coverage is expected to focus along this front as it
moves south, with drier air behind the front ending rain chances for
the coastal waters by Wednesday night. Northeast winds behind the
front may reach caution criteria early Tuesday morning, with light
northeast flow expected to persist over much of the upcoming week.
May see another brief window for caution flags on Thursday as a
reinforcing front moves into the Gulf. Otherwise, expect seas
generally in the 2-4 ft range through mid-week.

Huffman

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 81 67 83 65 87 / 40 20 10 0 0
Houston (IAH) 85 71 85 68 88 / 50 30 20 0 0
Galveston (GLS) 85 76 84 75 85 / 40 40 20 10 0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

Discussion...45
Aviation/Marine...14

[jasons2k]

.24" yesterday. Gives me .31" so far for this whole system.

[srainhoutx]

Monday morning briefing from Jeff:

First cool front of the fall season drifting toward SE TX this morning.

At sunrise this morning a cold front extended from NE TX to near Del Rio with excessive rainfall ongoing along the I-35 corridor near/north of San Antonio. Flash flooding is in progress over portions of San Antonio area this morning. Best moisture today will be WSW of a line from about Galveston to Spring to College Station with drier air filtering in from the NNE. Actual cold front will move to near US 59 by the late afternoon hours, but winds are already out of the N ahead of the boundary which will likely help to reduce convergence. However trigger temperatures this afternoon in the lower 80’s may help to overcome convergence needed along the boundary to generate convection and some of the meso scale models have been fairly aggressive with organized storms over our SW counties this afternoon into the evening hours.

Front should reach the coast early Tuesday with a drier air mass building into the region late Tuesday into the rest of the week. Forecasted dewpoints fall into the 50’s Thursday-Saturday and expect morning lows to bottom out in the upper 50’s to lower 60’s during this period with highs in the low to mid 80’s. This will be some of the coolest overnight lows since last May. Rain chances should zero out on Wednesday and remain below 10% into the weekend.

97L:
A broad area of low pressure 1100 miles east of the Windward Islands is gradually becoming better organized and there is a high potential (90%) that the system will develop into a tropical depression over the next 5 days as it moves generally westward toward the eastern Caribbean Sea. This system is currently located very low in latitude and conditions downstream over the Caribbean Sea are forecast to be favorable for development. One should remember at this time range to be cautious of model guidance as wild swings between runs and models are likely. At this point there looks to be the potential for a fairly significant tropical system in the Caribbean Sea late this week.

[DoctorMu]

.24" yesterday. Gives me .31" so far for this whole system.

It's a semi-bust for me as well in CLL at 0.45 in. The west side of town saw significant rainfall, but the AggieDome buffered a complex array of storm with definitely a halo effect. Hoping the lift from the cold front initiates sigificant rainfall. Really keep hoping to sit down sprinklers for the season. Otherwise, will run them tomorrow am. We're folding into St. Augustine brown path season and night watering is now off the table.

[DoctorMu]

Prediction for IAH Thursday and Friday nights are lows of 61°

Conroe about 58°F both nights

CLL about 59°F


Very, very close to breaking the 60°F barrier at IAH. Not bad for late September.

[Ounce]

.24" yesterday. Gives me .31" so far for this whole system.

Gratz!

[jasons2k]

Yeah, about a half-inch for the whole month...

[CrashTestDummy]

Started the morning with a 20% chance of rain, so, of course, we got 5 INCHES of water today.

[Katdaddy]

The cold front has pushed offshore this morning. Low clouds and a band of very light showers N and W of Houston remain over SE TX. The cold front will continue to push further offshore tonight resulting in clearing skies and drier air with another push of cooler and drier air on Thursday resulting in a nice Fall weekend. Lows Friday and Saturday may be the coolest temps since early May.