Area Forecast Discussion
Issued by NWS Brownsville, TX

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133
FXUS64 KBRO 301145
AFDBRO

Area Forecast Discussion
National Weather Service BROWNSVILLE TX
645 AM CDT MON MAY 30 2016

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

&&

.AVIATION...Light easterly flow will continue through mid
morning and begin to increase in the afternoon with daytime
mixing. Expect MVFR CIGS to improve to VFR conditions by mid
morning as well and continue through the day. A few isolated
showers and thunderstorms are possible over the western and
northern counties but do not expect to reach the RGV. Winds
decouple in the evening remaining light through early Tuesday.

&&

.PREV DISCUSSION... /issued 351 AM CDT MON MAY 30 2016/

SHORT TERM (Today through Tuesday): Elongated upper level low
across the Desert Southwest will put South Central TX under
diffluent flow aloft while SE influx of moisture across the area.
Weak perturbations within the flow in addition to an increase in
low level moisture will enhance ISO to SCT showers and
thunderstorms along and E of the Sierra Madre Mountains. Most of
the convection will remain focus over the W for the afternoon
hours as convection initiates North and West of the CWA. Models
guidance NAM/ECMWF show less chances of pcpn developing while the
GFS is the outlier with above 30 percent. Lean towards the lower
end of the guidance. High temperatures will climb into the 90s
once again with heights rising and above 18 to 19C 850MB
temperature. Pressure gradient will be weaker today keeping a
moderate Southeast flow across the area with a mix of CU clouds
developing in the afternoon hours. Heat index climb into the 102
to 105 range for much of the area. SPC still keeps us in a general
thunderstorm category but could not rule out with thunderstorm
outflow boundaries to reach the northwestern corner and one
thunderstorm to sneak into the CWA. Overnight low temperatures
will remain on the warmer side remaining in the upper 70s.

Tuesday will be a repeat of the weather pattern as elongated trough
almost remains stationary over the Desert SW. Diffluence flow aloft
will prevail through the following 12 hours enhancing another round
of convection over the S Central portion of the state. Precipitable
water values increase into 1.8 in with time heights showing a much
deeper layer of moisture through the column. This will enhance round
of convection northern ranchlands and the western counties of the cwa.
Temperatures will remain in the mid to upper 90s and close to 100s
out West.

LONG TERM (Tuesday Night through Sunday): Low to mid level
moisture across the southern and central plains Tuesday will allow
convection to develop across portions of the state Tues. night
into Wednesday as the combination of a 500mb trough across the
north central United States and a 500mb low across northern Mexico
provides an unstable atmosphere across the southern plains.
Showers and thunderstorms...some producing heavy rainfall...will
develop across portions of south Texas Wednesday into Thursday as
the 500mb low across northwest TX continues to provide steepening
lapse rates across the area. In addition...a weak cold front will
move through north TX Wed. and move into south TX Thurs. allowing
moisture to pool along and ahead of the frontal boundary. Rain
chances will increase from west to east Wednesday into Thursday
and remain high into Friday as broad low pressure develops across
the stalled frontal boundary draped across the middle and lower TX
coast. The 500mb low is progged to meander across portions of
central into southwest TX Friday into Saturday and this scenario
could provide a considerable amount of rainfall across portions of
south TX through the rest of the week into the weekend. Flash
flood watches may be needed for the CWA through the rest of the
forecast period if the upper level system lingers across central
or south TX Saturday into Sunday as currently advertised by the
00Z global synoptic models.

MARINE:
Now through Tuesday...surface high pressure over the Gulf of
Mexico slightly moves East weakening pressure gradient along the
coastal waters. This will keep a moderate SE flow across the Gulf
waters through the short term prd. The SE winds will prevail
through the period with possible SCEC by mid morning and early
afternoon quickly lowering in the evening hours. Seas remain
between 2 o 4 feet through much of the prd.

Tuesday night through Friday...Moderate to strong southeast winds
will prevail across the coastal waters Tuesday night into
Wednesday with low pressure across west Texas and high pressure
across the northeast Gulf of Mexico. The pressure gradient will
remain relatively strong across the lower TX coast Wednesday and
Thursday before weakening Friday as a weak cold front moves into
the coastal waters Fri. afternoon. Moderate southeast winds
Thursday will become light to moderate Friday as a result.

&&

.BRO Watches/Warnings/Advisories...
TX...None.
GM...None.
&&

$$

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