Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 190434

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1134 PM CDT Sun Jun 18 2017

Cirrus continues to stream over SE TX. SOme lower clouds will
begin to develop between 06-09z and MVFR cigs possible later
tonight into early Monday. Cigs will scatter out after 15z Monday
with generally VFR conds for Monday afternoon. The HiRes NMM and
ARW show some streamer showers possible early Monday morning near
the coast and added a VCSH for KGLS and KLBX for the morning. A
weak front over North Texas will approach SE TX in the afternoon
and the gradient will become weak with a light wind shift to the
W-SW. Fcst soundings for 00-03z show PW values surging to 2.00
inches with some instability. The combination of the front and
this instability should foster some showers and thunderstorms on
Monday evening. Have added VCTS for TAF sites...generally south of
KCXO to the coast. VFR conditions expected to redevelop after 06z
Tuesday.  43


.PREV DISCUSSION... /ISSUED 943 PM CDT Sun Jun 18 2017/

Evening surface analysis and regional radar mosaic showed a slow-
moving cold front stretching from the Davis Mountains to Abilene
to the D/FW Metroplex. With this boundary remaining well north of
the region overnight, have removed mention of thunderstorms from
the northeastern counties. The coastal waters and immediate
coastline may see a few showers skirt it closer to sunrise as a
mid-level disturbance over southern Louisiana pushes farther into
the Gulf but surface observations in the vicinity of this ongoing
activity is reporting no rain and have kept mention out of the
forecast for tonight. Otherwise, expect another warm night with
overnight lows in the mid 70s to low 80s under partly to mostly
cloudy skies.


PREV DISCUSSION... /ISSUED 331 PM CDT Sun Jun 18 2017/

Tonight and Monday...mesoscale models suggest possibility of a
complex of showers and thunderstorms developing over OK or NE
Texas overnight then dropping southward toward northern portions
of the forecast area very late tonight or Monday morning. Airmass
more capped this far south and unclear how far it will make it
into the forecast area...but have shower chances in Houston County line with surrounding zones...then Monday for
mainly northern half of CWA. Cold front is forecast to approach
from the north but stall out before quite making it into the area.

Tuesday and beyond forecast becomes increasingly dependent on
system now over western Carribean Sea forecast by all the models
to become better organized as it moves N or NW and emerges into
the Gulf of Mexico. NHC gives this system a 70 percent chance of
becoming a tropical cyclone over the next 48 hours and a 90
percent chance over the next 5 days. The track forecast for this
system is very complicated. An upper level trough over western seen in model progs and water vapor imagery...will tend
to draw the system north perhaps toward the northern Gulf coast
and impose shear on the system. However there is some
indication...especially in latest runs...of this upper trough
becoming more cut off with steering currents then guiding the
system more toward the west on the northern flank of this cut off
low and with 500 mb ridge to the north. ECMWF...GFS...Canadian...
have all trended farther west with their tracks today perhaps due
to the handling of these features. Based on todays trends Texas
coast could see some impacts as early as late Wednesday or
Thursday. That said with complicated steering pattern and still no
well defined low center there remains much uncertainty in the
track of this system and all will need to continue to monitor. A
track to the east would mean little impact. As far as strength of
system...shear over Western Gulf and available intensity guidance
would suggest most likely no stronger than a tropical storm but
will have more information on forecast intensity from the National
Hurricane Center when and if the tropical cyclone forms. 18

A weaker pressure gradient has helped to lower winds this afternoon
but seas have remained slightly elevated. However will be expecting
things to continue to quiet down tonight and will let the SCEC
expire as planned. Generally light SE winds on Mon will be
transitioning to a E/NE flow by Tue/Wed as the tropical
disturbance currently near the Yucatan finally makes its move into
the central Gulf. There is still a lot of uncertainty with the
eventual track of this system with much of the US Gulf coast in
play. Mariners/marine interests should stay up to date with the
latest information with this system. 41


College Station (CLL)      76  94  75  94  73 /  10  20  10  10  10
Houston (IAH)              78  95  75  95  73 /  10  20  10  20  10
Galveston (GLS)            82  90  80  90  79 /  10  10  10  20  20




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