Area Forecast Discussion
Issued by NWS Brownsville, TX
FXUS64 KBRO 231110
Area Forecast Discussion
National Weather Service BROWNSVILLE TX
510 AM CST Mon Jan 23 2017
.DISCUSSION...Updated for latest aviation discussion below.
.AVIATION...Very favorable conditions for takeoffs and landings
will occur at the RGV airport terminals during the next 24 hours.
High pressure will promote clear skies and light winds today.
Southerly winds begin to increase later tonight as the high cell
moves east and the pressure gradient between it and a low emerging
into the Central Plains increases.
.PREV DISCUSSION... /issued 416 AM CST Mon Jan 23 2017/
SHORT TERM:(Now through Tuesday): Tweaked this morning`s min
temps a bit higher, as winds have stayed up in the 8-10mph range.
"Chamber of Commerce" type day still in store for today, as
current water- vapor satellite imagery shows ridging aloft
building into Texas from the Southern Rockies. Skies over the
state are almost entirely clear, except for a few clouds in the
Panhandle. Sunny skies to prevail as atmospheric column remains
VERY dry (though some haze is possible this morning near the
wildfire in Brooks county). 00Z BRO raob measured just 0.24" of
precipitable water, only 0.01" above the daily minimum recorded,
per SPC climatology. Went ahead and blended in ECMWF temps for
highs today, which had the effect of raising them a couple
degrees, to 8-10 degrees above normal. Winds stay very much on the
light side as surface high pressure migrates across the region.
For tonight, SSE winds set up as a surface low deepens over the
Central Plains. This brings dewpoints back up the mid-50s near the
coast by daybreak. Overnight lows are also milder as a consequence,
generally in the 50s to near 60 at BRO. On Tuesday, winds continue
cranking up from the south, especially in the coastal counties where
a Wind Advisory may be needed. H85 winds take on more of a westerly
component, leading to another heat spike, though it doesn`t appear
to be as extreme as Saturday`s.
LONG TERM (Tuesday Night through Sunday):Models are in better
agreement today with the mid and upper level flow and now show
much better agreement with pop and temperature fields. Forecast
confidence is above average for this forecast package.
A series of shortwave troughs moving in from the Pacific and from
Canada to carve out a longwave low pressure trough across North
America and the Conus. As mentioned yesterday 500mb heights and
1000-500mb thickness steadily lower through the week which will
result in a steady cooling trend. This cooling trend commences
with the frontal passage late Tuesday night or early Wednesday
with little chance of rain with mainly a band of clouds. Zonal
flow aloft and a extended period of northeast wind at the surface
to slowly push temperatures towards normal Thursday. A reinforcing
shot of cooler air moves in for the weekend along with a chance of
rain. The upper trough becomes positively tilted with the Western
end becoming pinched off and becoming closed over NW Mexico and a
stronger shortwave trough surges south through the Central Plains
in association with a strong polar jet diving south out of Canada.
This will bring about a stronger shot of Canadian air Saturday
along with developing overrunning conditions increasing the rain
chances next weekend. With all three big models, GFS, ECMWF and
Canada are on board with this trend temperatures will likely fall
into the 60s and maybe even into the 50s depending on how
persistent the rain may become.
MARINE:(Now through Tuesday): Latest conditions reported at Buoy
42020 as of 250am CST were N winds at 16G19KT with seas of 4 ft. As
such, have extended Small Craft Exercise Caution wording over the
outer Gulf Waters for one more period. Winds and seas will continue
to diminish over the course of the day as surface high pressure
moves across the NW Gulf of Mexico. Winds will switch to southerly
overnight, increasing to moderate speeds as a storm system deepens
in the central High Plains. Seas will take a little longer to
respond. At any rate, expect SCEC conditions to return to the Gulf
Waters tonight, with higher-end SCEC/lower-end Small Craft Advisory
conditions for all of the coastal waters likely for Tuesday daytime.
Seas build to 6-7 ft. over the outer waters by Tuesday afternoon.
Tuesday night through Friday...a cold front moves through late
Tuesday night or early Wednesday with a moderately strong
north to northeast wind and building sea through Thursday. Winds
turn east and seas subside briefly Friday before a stronger surge
of north winds moves into the Western Gulf Saturday.
CLIMATE: Near-record high temperatures are forecast for Tuesday.
Daily records for Brownsville, Harlingen, and McAllen are 86F,
87F, and 89F, respectively. Forecast highs for that day are 87F at
Brownsville, 88F at Harlingen, and 91F at McAllen.
FIRE WEATHER: Dry conditions will continue today, with minimum
relative humidities in the 13-20% range, except 20-30% near the
coast. However, 20-foot wind speeds of generally 8mph or less will
remain well below any fire weather product criteria. On Tuesday,
moisture gradually returns to the eastern zones on increasing SSE
winds with 20-ft. speeds approaching 20mph. Lower RH`s persist out
west, but 20-ft. wind speeds will be lower as well...10mph or less.
At this time, it appears unlikely that Red Flag Warning criteria
will be met, though a Fire Danger Statement for areas generally
along and east of Hwy. 281 is quite possible.
This product is also available on the web at: