Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 251512

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1012 AM CDT Mon Sep 25 2017

Temps warming rather quickly this morning and 12z soundings
support high temps in the upper 80`s NE to the lower 90`s SW.
Have bumped max temps up a few degrees over mainly the central
and southwest parts of the area. 12z soundings show a convective
temp around 87 degrees but considering showers are already
developing, it`s probably a few degrees cooler. Daytime heating
should foster additional showers and storms through the afternoon.
Other than the minor tweaks to the sky grids and Max T grids,
rest of the forecast looks on track. 43


.PREV DISCUSSION... /ISSUED 606 AM CDT Mon Sep 25 2017/

Satellite and obs show some patchy fog developing north and west
of Houston. Though it looks fairly dense in a few spots, expect
the TAF sites to stay MVFR at worst. Any of those MVFR spots
should rapidly improve to VFR, with another bout of isolated to
scattered showers (and maybe a storm) this afternoon with SE
winds to near 10 knots. Going into tonight, there`s still no
expectation of change from the persistent pattern, with winds
backing off and skies clearing. Looking for fog again overnight,
with the most impact for the usual suspects like CXO.

PREV DISCUSSION... /ISSUED 353 AM CDT Mon Sep 25 2017/

Looking at 08Z observations and available GOES 16 satellite data,
low clouds and fog appear less than the last couple of mornings.
There is still plenty of time for fog to develop through the
morning hours and expect there to be more patchy fog to develop
across SE Texas. Today`s forecast is setting up much like the last
couple of days. There may be enough moisture to support a few
showers and thunderstorms with day time heating. Aloft 500mb
heights have dropped a few decameters with the weak upper low over
the northern Gulf coast. Given neutral vertical motion in the
atmosphere, diurnal heating and any sea breeze boundary should be
enough for storm initiation so will keep 20/30 PoPs in the
forecast for today.

Tuesday into Wednesday upper level riding should expand with
maybe a few vorticity maximums rotating through the flow from an
upper level low over the Desert SW. While 500mb heights rise
slightly so does overall atmospheric moisture. Again with daytime
heating look for 20 to 30 PoPs to continue through Thursday.
Overall models are not highlighting any one day for higher rain

Thursday night into Friday while upper level ridging remains over
Texas, a deep trough develops over the Great Lakes. This gives
support for a cold front to push through the area later on Friday.
The front still looks like a strong backdoor front with NE flow,
but models are showing it pushing through later on Friday instead
of earlier like previous forecast data had shown. Still there is
good confidence that the front will push through but the effects
may not be felt until the weekend.

Conditions behind the front Saturday and Sunday do look to be
more fall like with high temperatures in the low/mid 80s and low
temperatures in the low/mid 60s. Surface dewpoints in the 50s
behind the front will feel refreshing compared the the air you can
wear 70 dewpoints. Relative humidity each afternoon could reach
below 40 percent for the weekend.


Light to moderate southeasterly winds can be expected into the
midweek, before backing easterly as pressures along the coast dip
slightly. Late in the week a cold front will cause winds to further
back to the northeast. A push of drier, slightly cooler air is
likely to increase winds and seas into the weekend. In the coming
days, the persistent onshore flow will cause tides to run several
inches above astronomical levels.


College Station (CLL)      90  72  91  73  90 /  20  10  20  20  20
Houston (IAH)              90  73  89  73  90 /  20  10  20  10  20
Galveston (GLS)            88  80  88  79  88 /  30  10  20  10  20




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