Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 260218

Area Forecast Discussion
National Weather Service Houston/Galveston TX
918 PM CDT Sun Jun 25 2017

An outflow boundary, or perhaps the actual front, was moving
southwestward into Chambers and Galveston counties and Trinity Bay
at 9:00 PM. There were quite a few other weaker boundaries that
were left over from the afternoon thunderstorms. An analysis of
the 00Z upper air surface showed a weakness in the 500 mb ridge
over the lower Mississippi Valley into the northern Gulf of
Mexico, a moisture axis associated with a 700 mb trough over the
upper Texas coast with another across norther LA into TX, and a
moisture axis at 850 mb associated with a pressure trough across
the southern portions of AL, MS and LA into SE Texas. The moisture
axis could be seen on satellite on Water Vapor and IR.

The HRRR, NAM12 and Texas Tech 3 km WRF all keep decent chances
for scattered showers and thunderstorms over the Interstate 10
corridor and the northwestern set of counties in the forecast
area. Least chances look to occur over the far northeastern areas.
Given the mesoanalysis and the short term high resolution model
forecasts, tweaked the rain chances upward over the central areas
through the remainder of the night. The NAM BUFR forecast
soundings show some potential for gusty winds for another couple
of hours this evening--this may best be realized over the coastal
waters and bays.



.PREV DISCUSSION... /ISSUED 631 PM CDT Sun Jun 25 2017/

Based off radar trends and GOES 16 visible, it looks like the so
called frontal boundary has moved to around a line from KCLL to
KIAH to KBPT. Convection may linger around for another 1-2 hours
so a few terminals may be impacted, namely KIAH with a strong
shower that produced a 23 knot wind gust but no lightning. Will
keep VCTS in TAF for next hour. Otherwise most of the convection
is in between terminals so may need to amend TAFs should
convection develop closer to the terminals.

I think the overnight period will be quiet and more stable than
the last couple of nights in which convection has developed around
09Z or after. So again will go convection free with TAFs until
late morning when day time heating will be needed to get storms
going along any existing boundaries. There was a plethora of
boundaries this afternoon so look for similar activity to form
tomorrow. Convective allowing models seem to hit the areas SW of
Houston mid morning and then the rest of the area late morning
into early afternoon.

For now do not see any MVFR conditions forming overnight but
there could be some patchy fog should clouds clear enough with
the calm winds.



College Station (CLL)      71  88  72  89  72 /  40  40  30  40  20
Houston (IAH)              73  87  73  88  73 /  40  60  30  50  20
Galveston (GLS)            78  85  78  85  78 /  40  40  30  40  30




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