Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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000
FXUS64 KHGX 272327
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
627 PM CDT Sat May 27 2017

.AVIATION...
Look for mainly MVFR ceilings to develop this evening and persist overnight
with south winds around 10 knots. Ceilings will lift tomorrow morning,
but not expecting VFR levels to be reached areawide until the late
morning through early afternoon hours. Expect SHRA/TSRA development
(some possibly strong/severe) tomorrow afternoon to our W and NW along
and ahead of a cold front with activity working its way into our area
late in the afternoon and on into the evening hours. Much of our area
will be settling into an increasing cloud and increasing rain chance
pattern as the upcoming week progresses.  42
&&

.PREV DISCUSSION... /ISSUED 346 PM CDT Sat May 27 2017/

DISCUSSION...
Warm start to the day along with a break in the cloud cover
allowed readings to climb into the 90s for most inland sites. Look
for a general repeat for most of the area tonight & early Sunday
with stratus redeveloping overnight then some scattering out
during the day Sunday.

Potent cap should keep precip chances low for the 1st half of the
day Sunday. But guidance shows this eroding in the afternoon and
mostly gone across northern parts of the region toward late aftn
and evening - about the same time a weak frontal boundary edges
closer to se Tx. Expect some fairly rapid storm development along
the front. Considering the instability, with fcst CAPES > 4000
J/kg and LI < -10C, expect some strong to severe cells to emerge
and make their way into northern parts of the region. Timing is a
touch different between models, but in general 4pm-midnight would
be of concern.

This diffuse front/boundary/outflow should make it closer to the
coast by Monday morning - about the time a disturbance in the sw
flow aloft approaches. A surge of deep PW`s moving up from the
western Gulf will further increase moisture values pooling along
the boundary to between 2-2.5". Similar to the event last week,
the potential for at least localized heavy rain exists. But the
challenge will again will be trying to fcst the boundary position
if/when it all comes together. Current guidance, for what it`s
worth this far out, depicts the region between I-10 and the coast
the place to keep an eye on late Sun night thru Mon aftn.

Tue into midweek, surface troffiness looks to persist somewhere
along the coast which should allow for periods of shra/tstms to
continue across the area. We should eventually lose this trof as
it washes out during the 2nd half of the work week, but should be
getting into a more active sw flow aloft too. So at a minimum,
30-50% diurnally driven pops look like a good starting place. Was
left a good set of pops thru the period and made very few overall
changes.

Beyond Sunday night, forecast confidence is fairly low as a lot of
what will eventually happen will be driven on the meso/microscale. 47

MARINE...
Onshore winds should strengthen enough for caution conditions this
evening. Otherwise, winds should diminish slightly on Sunday as a
frontal boundary moves into SE Texas from the north. This should
result in slightly lower seas and with tide levels continuing to
lower to near normal levels.

The beach hazards for this afternoon will continue with stronger rip
currents possible. Winds on Sunday will be around 15 knots which
may lead to some rip currents still be possible. 40

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      77  91  70  82  69 /  10  40  70  60  40
Houston (IAH)              78  92  74  81  71 /  10  30  70  70  40
Galveston (GLS)            81  88  78  82  76 /  20  20  60  80  40

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION through Sunday morning for
     the following zones: Coastal waters from Freeport to the
     Matagorda Ship Channel out 20 NM...Coastal waters from High
     Island to Freeport out 20 NM...Waters from Freeport to the
     Matagorda Ship Channel from 20 to 60 NM...Waters from High
     Island to Freeport from 20 to 60 NM.

&&

$$

Discussion...11
Aviation/Marine...42



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