Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
FXUS64 KHGX 162155
Area Forecast Discussion
National Weather Service Houston/Galveston TX
355 PM CST Mon Jan 16 2017
Though in a relative lull in activity this afternoon, the story
for most of the week will be continued unsettled weather. Like
we`ve seen today, the character of expected precipitation is not
expected to be continuous rain, but there will be high chances for
off and on showers and storms through Thursday, occasionally
enhanced by passing weather features. The severe weather around
the Houston metro this morning was likely the best opportunity for
severe weather in this period, but some more is possible ahead of
a cold front today, and can`t be totally ruled out along the coast
tomorrow. Friday does look to be drier in the wake of a coastal
low, but some chance for precipitation should return for the
weekend. Finally, a cold front Sunday morning should clear things
out for the first half of next week.
Rest of today through Thursday...
Radar shows showers still ongoing in our north, and while there
have been a smattering of light echoes farther south, the limited
vertical extent of cumulus outside the window implies the cap has
indeed been too strong to overcome, despite the extra heating.
Indeed, SPC mesoanalysis shows at least moderate instability for
the region, but MLCAPE is significantly lower (and with CINH!),
and it appears that is what`s winning out. Winds at College
Station have switched to consistently northwest, and the dewpoint
has dropped to 62, suggesting it has seen the arrival of the
oncoming front. However, this appears to be a bit of a vanguard,
as an APRS site in Madison County and Crockett appear to be ahead
of or just entering the frontal zone at 3pm.
The front should continue to advance, and provide a focus for
continued showers and perhaps a storm. There does seem to be a
modest amount of low level shear near the front, so don`t want to
rule out some organized updrafts for the strongest cells,
especially if, like this morning, we get low-topped convection. Similar
to the SBCAPE/MLCAPE comparison mentioned earlier, while MLCAPE
is limited at this hour, mesoanalysis shows available MUCAPE, and
the front may be enough to tap into any remaining instability for
the nighttime hours. That said, none of the HRRR, TTU WRF, or NCAR
WRF ensemble spark more than numerous light showers until a subtle
midlevel shortwave comes through Tuesday night into Wednesday
morning. So, this concern may simply be for naught.
After the subtle midlevel trough passes through to enhance PoPs
for Tuesday night and Wednesday, we drop back down to more of a
"baseline" high chance inland, while PoPs remain elevated near the
coast as a coastal trough/weak surface low develops Thursday and
moves up the coast. Once it moves through, some brief offshore
flow wrapping around the low pressure center looks to dry things
out briefly, though onshore flow should return by sunrise Friday.
Friday and beyond...
Though the models suggest some light rain near the coast Friday,
opting for now to stay dry until perhaps Friday night or Saturday
and a closer approach of the next front. As the next bowling ball
upper low ejects through the area Sunday, we should see a surface
low roll through Oklahoma, and bring a clearing front through
Southeast Texas Sunday morning. After that, brief midlevel ridging
should keep things quiet into early next week.
Seas of 5 to 6 feet offshore this afternoon should gradually come
down tonight as winds relax and cold front creeps southward over
SETX. Expect the very moist airmass with dewpoints in the upper 60s
to flow over the cooler shelf water which should become more
favorable for the formation of sea fog if a little more dry air just
above the surface isn`t present than what soundings indicate. Fog
threat especially after midnight through mid morning and possibly
longer as winds back to the east southeast. This pattern holds
through Wednesday before a more potent short wave kicks through and
could increase winds and veer them to more southerly in direction
possibly lessening the fog threat. Potent system arriving
Sunday/Monday and will likely bring SCA and possibly westerly Gale
conditions to the coastal waters.
VFR across the south with MVFR at CLL where weak cold front has
intruded into. Front should continue to creep southward and with
cooling tonight expect cigs to come down in the vicinity of the
front first dropping into MVFR then IFR and even LIFR possible
shifting southward throughout the night. Rainfall on the increase
tonight as weak steady lift prevails over the boundary. S/W moving
in from the southwest Tuesday should help to get more lift over the
boundary going and reinforced the rain/lowered CIGS throughout the
afternoon and evening.
Wet across the area through Saturday for the most part so low fire
concerns. Potent Pacific frontal system will swing through late
weekend/early Monday and has the potential to bring dry/very dry
conditions with abundant wind so may have a slight uptick in fire
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 57 61 52 65 54 / 60 60 70 70 50
Houston (IAH) 64 69 59 72 60 / 50 60 70 70 60
Galveston (GLS) 64 69 63 69 62 / 50 40 60 60 60
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 4 PM CST this
afternoon for the following zones: Waters from Freeport to
the Matagorda Ship Channel from 20 to 60 NM...Waters from
High Island to Freeport from 20 to 60 NM.