October 2017 - Halloween Forecast/Rain Chances

[Katdaddy]

Rain and thunderstorms are back in the SE TX forecast today through Wednesday afternoon with some locally heavy rains as deep tropical moisture spreads across the NW GOM. By Wednesday night into Thursday, SE TX begins to dry out for the rest of week and weekend.

Hazardous Weather Outlook
National Weather Service Houston/Galveston TX
443 AM CDT Mon Oct 2 2017

TXZ163-164-176>179-195>200-210>213-226-227-031200-
Austin-Brazos-Burleson-Colorado-Fort Bend-Grimes-Harris-Houston-
Liberty-Madison-Montgomery-Polk-San Jacinto-Trinity-Walker-Waller-
Washington-Wharton-
443 AM CDT Mon Oct 2 2017

This hazardous weather outlook is for portions of Southeast Texas.

.DAY ONE...Today and Tonight

Increasing rain chances could bring periods of locally heavy rainfall.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Elevated rain chances could bring periods of locally heavy rainfall
Tuesday and Wednesday. Expect decreasing coverage and intensity
during the day on Wednesday from east to west.

.SPOTTER INFORMATION STATEMENT...

Spotter activation might be needed during the first half of the week.

[srainhoutx]

A couple of features in the Medium to Longer Range to monitor this week. One is what appears to be a fairly strong Cold Front associated with a very deep Mid Continent Long wave Trough organizing this coming weekend as well as a festering area of Tropical Disturbed Weather near the Yucatan Peninsula associated with a monsoonal trough/gyre. Any organization would be very slow and likely picked up and carried out to the ENE as that deep trough and its associated cold front push into the Gulf of Mexico early next week.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Mon Oct 2 2017

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Disorganized showers and thunderstorms across portions of the
Yucatan Peninsula, Central America, and the northwestern Caribbean
Sea are associated with surface trough that is interacting with an
upper-level low. Some slow development of this system is possible
by the end of the week or this weekend while it drifts northward
into the southern Gulf of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

Forecaster Cangialosi

[tireman4]

000
FXUS64 KHGX 021201
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
701 AM CDT Mon Oct 2 2017

.AVIATION...
A more wet and overcast pattern beginning to take shape through
the period. Early period showers should transition to more
scattered clusters of rain with embedded thunderstorms this
afternoon. A high slug of Gulf moisture and a weak wave passing
onshore throughout the day will increase precipitation probabilities.
Primarily VFR BKN-OVC decks...lowering ceilings to MVFR within
heavier precipitation. An anticipated break in overall convective
coverage this evening...then rain and thunder expected to return
again early Tuesday morning (overnight hours) as weak disturbances
within a moist northern Gulf easterly flow pattern make their way
onshore. 31

&&

.PREV DISCUSSION... /ISSUED 442 AM CDT Mon Oct 2 2017/

DISCUSSION...
Showers have begun to move into the eastern parts of our area
along the leading edge of deeper moisture easily seen on GOES
total precipitable water vapor imagery. More development can
be expected today with an increase in coverage anticipated
tonight and on into Tuesday and Tuesday night as even deeper
moisture surges into the area from the east. Locally heavy
rainfall will be possible, and WPC has outlooked parts of our
area in a marginal risk on their Day 2 Excessive Rainfall
Outlook. The area looks to see a significant decrease in
coverage/intensity from east to west beginning some time
during the day on Wednesday and especially on into Thursday
as precipitable water values lower underneath building mid/
upper level high pressure. Above normal temperatures are
anticipated for the end of the week, and they`ll probably
continue into the weekend as we wait for a possible cold
frontal passage around seven days for now. 42

MARINE...
The pressure gradient between eastern U.S. high pressure and
southern Gulf low pressure will become tight enough to produce an
enhanced easterly flow pattern over our coastal waters through the
entire work week. Caution flags will likely be needed as early as
tonight with Advisories not out of the question by late tomorrow
(Tuesday) night. This persistent easterly fetch will pull in a
longer period swell. This will increase offshore sea heights to
between 6 to near 9 feet at mid-week and pick up coastal water
levels to between 3 to 3.5 feet during Tuesday through Thursday`s
high tide times. This week`s impacts will be coastal water run up
(during high tides) along eastern-facing shorelines and stronger rip
currents. 31

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 90 74 85 73 87 / 20 30 60 50 30
Houston (IAH) 88 74 85 72 88 / 40 40 60 50 40
Galveston (GLS) 87 78 84 78 87 / 50 50 60 50 40

&&

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

$$

Discussion...42
Aviation/Marine...31

[Katdaddy]

COASTAL HAZARD MESSAGE
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
148 PM CDT MON OCT 2 2017

...COASTAL FLOOD ADVISORY IN EFFECT UNTIL MIDNIGHT CDT TONIGHT...

.STRONG EAST TO NORTHEAST WINDS HAVE DEVELOPED ALONG THE UPPER
TEXAS COAST AND GALVESTON BAY. THESE WINDS ARE INCREASING TIDE
LEVELS ABOUT 1 TO 2 FEET ABOVE ASTRONOMICAL TIDES. GALVESTON
COUNTY EMERGENCY MANAGEMENT REPORT WAVE RUN UP AND SURF NEARING
HIGHWAY 87 ALONG BOLIVAR PENINSULA. TIDE GAUGES SHOW WATER LEVELS
AT 3 TO 3.5 FEET ABOVE MEAN LOWER LOW WATER. WATER FROM ROUGH SURF
COULD RUN UP ON HIGHWAY 87 THROUGH THE EVENING HOURS. WESTERN
PORTIONS OF GALVESTON BAY MAY ALSO EXPERIENCE HIGHER TIDES AND
COULD IMPACT LOW LYING AREAS FROM KEMAH TO SAN LEON.

TXZ214-238-030300-
/O.NEW.KHGX.CF.Y.0009.171002T1848Z-171003T0500Z/
CHAMBERS-GALVESTON-
148 PM CDT MON OCT 2 2017

...COASTAL FLOOD ADVISORY IN EFFECT UNTIL MIDNIGHT CDT TONIGHT...

THE NATIONAL WEATHER SERVICE IN HOUSTON/GALVESTON HAS ISSUED A
COASTAL FLOOD ADVISORY, WHICH IS IN EFFECT UNTIL MIDNIGHT CDT
TONIGHT.

* COASTAL FLOODING...TIDAL WATER LEVELS ABOUT 3 TO 3.8 FEET ABOVE MEAN LOWER LOW WATER.

* TIMING...THIS AFTERNOON INTO TONIGHT.

* IMPACTS...WATER IMPACTING HIGHWAY 87 ON BOLIVAR PENINSULA. HIGHER TIDES FOR WESTERN
PORTIONS OF GALVESTON BAY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A COASTAL FLOOD ADVISORY INDICATES THAT ONSHORE WINDS AND TIDES
WILL COMBINE TO GENERATE FLOODING OF LOW AREAS ALONG THE SHORE.

[Katdaddy]

Expect scattered showers and thunderstorms to increase by late morning into the afternoon across SE TX with locally heavy rainfall possible with a decrease in activity by this evening. A high pressure ridge will build across TX tomorrow bring drier and hot weather through the weekend.

[DoctorMu]

We could use some rain today up in CLL.

Strong cold front next Tuesday will finally usher in Fall weather.


Area Forecast Discussion
National Weather Service Houston/Galveston TX
1031 AM CDT Tue Oct 3 2017

.UPDATE...
No major change with the forecast for the update. Moisture/precip
continuing to move inland this morning as the moderate/strong on-
shore flow persists. Local soundings indicating that the high PWs
have moved into the area and with the breaks in the cloud deck we
should see an uptick in development through this afternoon (espe-
cially over our SW zones). 41

&&

.PREV DISCUSSION...

Southeast Texas will have one more day today with elevated
chances of showers and thunderstorms before mid/upper level
ridging builds across the state, dries the area out, and warms
temperatures back up. So far early this morning, radar is
indicating only isolated to widely scattered northwestward moving
activity. Models are insistent on increasing coverage beginning
before sunrise and persisting through most of the day as storms
spread inland. With precipitable water values hovering around 2.30
inches per GOES total precipitable water vapor imagery, locally
heavy rainfall could still happen if any training can set up (see
WPC`s Day 1 excessive Rainfall Outlook and associated discussion).
The area`s rain chances decrease rapidly tonight and tomorrow as
ridging begins to settle on in, and anticipate little to no rain
for a majority of Southeast Texas for the remainder of the week.
Much of the area should stay dry over the weekend too, but we`ll
have to keep an eye on what type of system possibly develops in
the Gulf of Mexico (see NHC`s latest Tropical Weather Outlook for
the latest information) and whether or not we get any moisture
from it. We continue to indicate a cold front moving through the
area early next week. 42

MARINE...
Lower pressure over the Bay of Campeche combined with higher
pressure along the northern Gulf will maintain a long fetch of
moderate to strong easterly winds and elevated seas. This has
started piling water up along the upper Texas coast. Current water
levels are running about 1.7 feet above normal tide table values.
These levels will be capable of producing minor coastal flooding
around times of high tide along the more susceptible roads along the
Bolivar Peninsula, Blue Water Highway and Beach Drive in Surfside.
As confirmed by Galveston Beach Patrol yesterday, rip currents will
also be a high risk. As such have kept the Beach Hazards Statement
in place which covers both the high tides, elevated surf and rip
currents. Expanded it to Matagorda coastline too. Winds and seas
will further increase into midweek, before a gradual improvement is
seen going into the weekend. 47

TROPICS...
Some computer models are depicting a low pressure area emerging in
the Caribbean and southern Gulf late this week. We`ll keep an eye on
things, but at the current time there really isn`t much to track. 47

AVIATION...
Periods of rain, some possibly training an locally heavy at times is
expected to increase in areal coverage and continue into the
afternoon. Tough to pinpoint exact timing and locations most
impacted, but anticipate mainly MVFR conditions with fluctuations
up/down based on precip trends. Look for overall coverage to
diminish this evening. 47

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 87 73 88 70 88 / 60 50 20 10 10
Houston (IAH) 87 74 87 71 88 / 60 50 20 10 10
Galveston (GLS) 87 79 88 78 87 / 60 50 30 20 20

[unome]

http://hurricanecity.com/models/models. ... stinvest=1

future Nate ? http://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=5

1. Satellite images and surface observations indicate that a broad area of low pressure has formed over the southwestern Caribbean Sea. Environmental conditions appear generally conducive for development, and this system could become a tropical depression within the next few days while it drifts northwestward to northward across the northwestern Caribbean and adjacent land areas and into the Gulf of Mexico by the weekend. Regardless of development, this system will likely produce heavy rains over portions of Central America during the next few days.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...60 percent.

[Rip76]

[snowman65]

WTH????

[cperk]

srainhoutx i'm really looking forward to your take on 90L.

[unome]

https://twitter.com/RyanMaue/status/915289256150622208

https://twitter.com/RyanMaue/status/915289757370011649

https://twitter.com/RyanMaue/status/915316057505755136

[unome]

http://blog.weather.us/

https://twitter.com/i/web/status/915327930456248321

@WeatherdotUS

A comparison of models (GFS/ECMWF/UKMET) shows consensus that #90L develops, exact landfall strength/location tbd

https://pbs.twimg.com/media/DLPl4vuVAAAdA28.jpg
https://pbs.twimg.com/media/DLPl4vuUQAAwQSU.jpg
https://pbs.twimg.com/media/DLPl4v_V4AAOE8G.jpg

[sambucol]

srainhoutx i'm really looking forward to your take on 90L.

Same here.

[TexasBreeze]

Looks more of a central/ne Gulf threat due to an approaching front/ trough coming down with sw flow pushing it away from TX. Still needs watching though of course!

[DoctorMu]

GFS, Euro, Canadian bring some TC close to the Louisiana coast Sunday emanating from the gyre.

[cperk]

Looks more of a central/ne Gulf threat due to an approaching front/ trough coming down with sw flow pushing it away from TX. Still needs watching though of course!

Agree, but the timing of that front will be critical.

[sambucol]

Looks more of a central/ne Gulf threat due to an approaching front/ trough coming down with sw flow pushing it away from TX. Still needs watching though of course!

Agree, but the timing of that front will be critical.

That's what I thought.

[cperk]

Hope to have some consensus maybe by Thursday or Friday.

[srainhoutx]

Just had my first chance to look at the 12Z Deterministic and Ensemble guidance. Let's hope the weaker and sheared ECMWF solutions are correct both with the trough/frontal timing and movement more NE. Climatology suggests that would be the most likely solution, but we should always monitor developing Tropical Disturbances in what I call the "Carla Cradle". Thankfully this is early October versus late August/early September. I also see we broke the previous annual rainfall total with 74.18 inches of rainfall since January 1st. And to think it's only early October. Yikes!!

[unome]

up to 70% in 5-day

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Tue Oct 3 2017

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Shower and thunderstorm activity in association with the broad
area of low pressure located over the southwestern Caribbean Sea
is beginning to show some signs of organization. Environmental
conditions are forecast to steadily become more conducive for
development, and this system is expected to become a tropical
depression within the next few days. The large disturbance should
move slowly northwestward to northward across or near the eastern
portions of Nicaragua and Honduras, move into the northwestern
Caribbean Sea on Thursday or Friday, and emerge over the southern
Gulf of Mexico by the weekend. Interests in Nicaragua and Honduras
should monitor the progress of this system over the next couple of
days. An Air Force Reserve reconnaissance aircraft is scheduled to
investigate the disturbance Wednesday afternoon, if necessary.
Regardless of development, this system will likely produce heavy
rains over portions of Central America during the next few days.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...high...70 percent.

2. A trough of low pressure located over central Cuba and extending
northward into the Straits of Florida is producing a broad area
of disorganized showers and thunderstorms across the southern
peninsula of Florida, the northwestern Bahamas, and the adjacent
Atlantic waters. Reports from land stations along the southeastern
Florida coast, in the northwestern Bahamas, and from nearby ships,
indicate that wind gusts of 40 to 50 mph have been occurring in
some of the heavier showers. Although significant development of
this system is not expected due to strong upper-level winds, brief
squalls will likely produce locally heavy rainfall and strong
gusty winds over portions of the Bahamas and the southern Florida
peninsula during the next couple of days.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...10 percent.

Forecaster Stewart