Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Brownsville Texas
535 am CST Monday Nov 30 2015
Discussion...updated for latest aviation discussion below.
Aviation...kbro Doppler radar shows an area of light drizzle over
the bro and hrl aerodromes right now...and moving rapidly north.
Meanwhile...mfe has some isolated precipitation approaching from
the south. This light rainfall will move away this morning...with
additional drizzle expected to redevelop during the afternoon
hours. Drier weather should briefly prevail this evening before
another round of more widespread light precipitation develops
around midnight and persists through the early morning hours of
Tuesday. No VFR ceilings are likely through the next 24 hours and
will vary as the light rainfall comes and GOES.
Previous discussion... /issued 330 am CST Monday Nov 30 2015/
Short term /today through Tuesday/...kbro Doppler radar shows a
persistent area of very light drizzle developing over extreme
northern neighboring tamaulipas state and continuously advecting
over the immediate three coastal counties of the bro County warning forecast area. The most
recent surface analysis indicated a stationary front still over the
western Gulf of Mexico. Observations from the three official climate
sites recorded high temperatures in the middle 50s at hrl and mfe and
60 degrees at bro.
Today...northerly to northeasterly surface winds courtesy of surface
high pressure centered over south Texas will continue to combine
with a southwest to northeast 500 mb flow overhead to generate very
light precipitation. Overcast skies will remain in place with no
warm air advection forecast to help mix out or thin the cloudiness.
The met model guidance was preferred and used for daytime high
temperatures...and appeared reasonable given Sunday recoded high
Tonight...surface winds back more towards the north (but remain
northeast) and intensify...resulting in an increase and spreading of
light precipitation. Inherited low temperatures appeared very
reasonable but were lowered a couple of degrees across the whole
bro County warning forecast area based on trends from the past couple of nights.
Tuesday...weak inverted surface troughiness forms along the Lower
Texas coast...helping to maintain the overrunning precipitation
already in place. The cooler met solution was once again preferred
over the warmer mav guidance...with adjustments made across the four
northern counties of the bro County warning forecast area for better consistency with
neighboring weather forecast office crp.
Long term /Tuesday night through Sunday/...a parade of shortwave
troughs and ridges to roll through south Texas the next 7 to 10
days as a typical late fall split flow pattern dominates North
America. Models remains in general agreement with the pattern but
as normal for this type of flow timing differences begin to show
up as you go out farther in time. This time around is no
different as the models begin to show larger spread the latter
half of the long term. That said forecast confidence is rather
high through Friday then begins to wane as we move into the
weekend and early next week.
First shortwave and its associated reinforcing cold front surge
remain on track for an overnight Tuesday early Wednesday morning
passage through deep south Texas. Model guidance remains in good
consistency with little adjustment to probability of precipitation and temperatures.
Temperatures to follow a falling trend through the day Wednesday
with chilly nights and cool to mild days Thursday and Friday as a
shortwave ridge moves through the Southern Plains and Texas.
After the near perfect Fall weather the next shortwave drops into
the 4 corners area Saturday and tracks slowly across Texas Sunday
and Monday with yet another wave following on its heels for
Tuesday/Wednesday of next week. With no significant return flow
becoming established due to the short wavelength between ridges
and troughs model guidances keeps rain chances, pops, on the low
side Sunday and Monday. Temperatures trend warmer but no sharp
increase in overnight or daytime temperatures in advance of the
next cold front some time next Monday.
Marine...now through Tuesday...buoy 42020 reported north winds
around 10 knots gusting to around 12 knots with seas slightly over
2.5 feet with a period of 8 seconds at 02 CST/08 UTC. Favorable
marine conditions are forecast today and tomorrow as surface high
pressure remains centered over south Texas and extended over the
Lower Texas coast. Small craft exercise caution and Small Craft
Advisory are not likely to be needed.
Tuesday night through Friday...next cold front pushes through
overnight Tuesday into early Wednesday with strong north winds and
hazardous seas persisting through Thursday . High pressure builds
over the western Gulf Friday and shifts east next weekend with
much improved marine conditions. Rain chances peak on Wednesday
with little to no rain Thursday and Friday.
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