000
FXUS64 KBRO 221144 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
644 AM CDT Thu Jun 22 2017

.DISCUSSION...Updated for latest aviation discussion below.

&&

.AVIATION...A few low clouds can be seen on the horizon this
morning, however beside a few CU clouds near the coastal airports
this morning, skies should be mostly clear. South winds will
increase and become rather gusty through the afternoon and remain
elevated into the evening hours as the pressure gradient
strengthens today.

&&

.PREV DISCUSSION... /issued 421 AM CDT Thu Jun 22 2017/

SHORT TERM (Now through Friday): The heat continues as the
subtropical ridge of high pressure over the Desert Southwest/West
Texas remains in control of the pattern. Meanwhile, TS Cindy will
continue to swirl into the Texas/Louisiana border later this
morning. As it does, the impacts to the coastal areas will lessen
through the day. Until then, however, some coastal flooding a
continued high surf will remain in place through the mid morning
hours as tides run a foot and half to up to 2 and a half feet
above predicted levels. Although coastal flooding impacts should
improve through the day, dangerous rip current will continue at
area beach through at least this morning until some of the higher
swells subside. As such, will keep all current headlines/products
in place for this morning`s forecast package and will allow the
next shift to cancel the rip current statement if conditions
improve by the afternoon.

With the aforementioned strong ridge of high pressure over the
region, dry northwest flow aloft will prevail with subsidence
continuing. Have actually increased high temps a degree or so today
given the records that were shattered yesterday. With 850 temps and
compressional heating, it is likely we will see a near carbon copy
for today with additional records broken. Heat indices will also
range from 105 to near 110 degrees. Overnight lows will not offer
much relief as values will still be several degrees above normal as
well.

Models do indicate that temperatures could be a couple of
degrees cooler now for Friday, but only if some moisture can return
with the southerly flow. Even then temperatures will still range
above the century mark across the the Mid to Upper Valley on Friday.
However, because the slightly cooler highs comes with a trade-off of
increased moisture, heat index values could be near or above 111
degrees across portions of the RGV and heat advisories may be
needed.

LONG TERM (Friday Night through Wednesday): A 500mb ridge over
the southwest United States and northern Mexico will initially
provide subsidence across Deep South Texas Friday night. An
inverted 500mb trough will develop over the western Gulf of Mexico
Saturday as a weak cold front moves south across north Texas. Low
and mid level moisture will increase across the state with
moisture pooling along a weak frontal boundary and across south
Texas this weekend. The combination of the mid level weakness,
daytime heating and abundant moisture will support a chance of
showers and thunderstorms this weekend. The weak frontal boundary
across the region along with the arrival of deeper moisture
(Precipitable water values 2.10+ inches) will support better
widespread coverage of rainfall on Monday and Tuesday. Lingering
moisture will allow a chance of showers and thunderstorms to
continue into mid week. Near normal temperatures for the weekend
into early next week due to the increase in cloud cover and rain
chances.

Fire Weather: Fire weather continues to be a concern today as
minimum RH values will range from the upper teens across the western
portions of the Zapata and Starr counties with to upper 20s towards
the I-69C corridor. Meanwhile, extremely warm day-time highs are
expected which will add to the fire danger threat. However, the
southerly 20-ft winds should remain below critical threshold, with
the exception of near coastal locations. Given that it is unlikely
Red Flag criteria will be met, will go with an RFD to highlight the
enhanced threat. Winds will be stronger on Friday, however moisture
should be increasing with it. However, if the moisture does not
return as quickly as expected, an enhanced fire weather threat will
continue.

MARINE (Now through Thursday): Buoy 42020 is reporting SSW winds at
around 15 knots and seas around 6 feet as of 3 AM CDT. Tropical
Storm Cindy is expected to make land fall near the Texas/Louisiana
border later this morning. Once that occurs, swells should improve
rather quickly. However, the surface pressure gradient will increase
through the day as string southerly flow returns as the tropical low
begins to interact with surface pressure systems over the Southern
Plains. As such, winds will increase across the Laguna Madre this
afternoon and a Small Craft Advisory will be needed. The gradient
will cause winds and seas to respond for Gulf waters east of Padre
Island later this evening through at least Friday afternoon. Small
craft advisories will posted for this as well.

Friday Night through Monday Night...Moderate southeast winds will
prevail along the lower Texas coast Friday night as low pressure
across west Texas interacts with high pressure across the Gulf of
Mexico. The pressure gradient will weaken across the western Gulf
Saturday as a weak cold front moves into north Texas. This will
allow light to moderate southeast winds Saturday to turn to the east
and diminish Saturday night into Sunday as the front moves into
central Texas. Light east winds should continue across the lower
Texas coastal waters Monday as the front moves into south Texas.
Rain chances begin to increase Friday night with better rain chances
expected through the weekend into early next week.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through this evening for TXZ251-256-257.

     High Surf Advisory until 10 AM CDT this morning for TXZ251-256-
     257.

     Coastal Flood Advisory until 10 AM CDT this morning for TXZ251-
     256-257.

GM...Small Craft Advisory for winds from 1 PM this afternoon to 7 PM
     CDT this evening for GMZ130-132-135.

     Small Craft Advisory until 10 AM CDT this morning for GMZ150-155-
     170-175.

     Small Craft Advisory from 7 PM this evening to 1 PM CDT Friday
     for GMZ150-155-170-175.

&&

$$

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