Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 201027
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
527 AM CDT Tue Jun 20 2017

...Tropical Storm Watch is in effect for the far southeastern Gulf
waters from 4 AM CDT Wednesday through 4 AM CDT Thursday...

.DISCUSSION...
As we head into the Summer Solstice late tonight...all eyes are
on Potential Tropical Cyclone Three (PTC3). This broad low over
the central Gulf is slowly advancing north along the far eastern
periphery of a Four Corners-centered upper ridge. Today`s forecast
movement of the low has it traveling west of north...or towards
the Texas-Louisiana line (Sabine River Valley). This morning`s
NHC advisory update has this (sub)tropical system strengthening to
Tropical Storm Cindy latter today with a landfall somewhere
between Galveston Bay and the central Louisiana coastline Thursday
morning. Sustained Tropical Storm winds will graze our eastern-most
Gulf waters. A Tropical Storm Watch is in effect for our eastern
waters from tomorrow morning through Thursday morning.

Another partially cloudy...hot and fairly humid day today as
afternoon temperatures eclipse the 90 F mark by 11 AM...topping
out in the interior middle 90s to coastal lower 90s by 4 PM.
Although difficult to discern within the surface analysis...there
is a diffuse surface boundary draped somewhere over the southern
half of the CWA...with PTC3/TS Cindy pulling this boundary further
south. Regional northeasterlies will begin to strengthen through
the day...more pronounced over the open waters to Small Craft
Advisories by late this afternoon for all Gulf waters (except for
the nearshore western waters and Matagorda Bay). Chances for Gulf
showers and thunderstorms will begin increasing over the next 24
to 36 hours to likely by tomorrow morning as PTC3/TS Cindy`s
northwestern convective bands begin to creep into our marine
zones. Wednesday into Thursday is when this (sub)tropical system
moves onshore somewhere over the upper Texas to southwestern
Louisiana coastline. The main threats appear to be mainly focused
on the marine with elevated water levels and tropical storm level
winds. The main eastern-southeastern county threat will be
locally heavy rainfall leading to flooding as bands of storms
rotate inland along the northwestern sector of PTC3/TS Cindy.
Skies will become mainly overcast tomorrow...with moderate
northeast winds...morning lower 80s with afternoon middle 90s over
the NW`ern CWA to around 90 F over the southeastern third of the
CWA (counties surrounding Galveston Bay) per the overcast and
periodic precipitation. More frequent rounds of precipitation
Wednesday evening through Thursday morning as PTC3/TS Cindy makes
landfall over the upper Texas/southwestern Louisiana coastline.
Needless to say...but an overcast and more wet end to the work
week.

The remnants of PTC3/Cindy will move north into eastern-northeastern
Texas through Thursday afternoon and be entering the ArkLaTex region
that evening. Eastern CWA POPS will remain at least high chance
through Thursday night...tapering off to low to moderate chances
for showers and storms early Friday. Storm total QPF for the eastern
half of the forecast area (through early Saturday) will average
between 2 to 4 inches...with locally 6 to 8 inches not completely
out of the question if the storm jogs more west than north.

Weekend weather has weak ridging attempting to make a comeback
with winds returning to onshore...mostly cloudy and humid with
average minTs in the upper 70s / average maxTs in the lower 90s.
Precipitation chances remain high...especially close to the
coast...as this is where the height weakness channel will lie
with a series of shortwave disturbances moving parallel to the
Gulf coast. Extremely high pwat air mass above 2 inches with weak
cyclonic-turning mid levels and unstable profiles all point to an
unsettled first weekend of the summer season.

A weak boundary moving into the area early next week will keep an
unsettled picture in place through the end of the period. Slightly
cooler middle levels...overcast with occasional rain/thunderstorm
occurrences will regulate early work week warmth to closer to 90
F than 95 F / overnight middle 70s. Precipitation chances remain
in the moderate chance category through mid week...with higher
probabilities focused across the southern third of the area where
the higher moisture/theta e axis is modeled to reside. 31


&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      95  76  94  75  92 /  10  10  10  40  50
Houston (IAH)              94  77  92  76  87 /  10  10  40  70  50
Galveston (GLS)            91  81  86  80  87 /  20  20  70  80  50

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...Small Craft Advisory from 9 AM this morning to 4 AM CDT
     Wednesday for the following zones: Waters from High Island
     to Freeport from 20 to 60 NM.

     Tropical Storm Watch for the following zones: Waters from High
     Island to Freeport from 20 to 60 NM.

     Small Craft Advisory from 4 PM this afternoon to 10 AM CDT
     Wednesday for the following zones: Coastal waters from High
     Island to Freeport out 20 NM...Waters from Freeport to the
     Matagorda Ship Channel from 20 to 60 NM.

     SMALL CRAFT SHOULD EXERCISE CAUTION from 9 AM this morning to 4
     PM CDT this afternoon for the following zones: Coastal
     waters from High Island to Freeport out 20 NM...Waters from
     Freeport to the Matagorda Ship Channel from 20 to 60 NM.

&&

$$

Discussion...31/47



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