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Area Forecast Discussion (AFD)

Issued by Brownsville/Rio Grande Valley, TX (BRO)

FXUS64 KBRO 172255 AAA

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
555 PM CDT Fri May 17 2019

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

.AVIATION...VFR to MVFR will be the rule through the next 24
hours. Moderate winds tonight will increase to windy levels
tomorrow. Convection is not likely to occur. 

.PREV DISCUSSION... /issued 224 PM CDT Fri May 17 2019/ 

SHORT TERM (Now through Saturday Night): Overhead mid level 
ridging will edge east into the northwest Gulf tonight, while 
surface high pressure remains ensconced across the Gulf. A mid 
level trough over the Great Basin area will support pressure falls
over the central High Plains. Low temperatures tonight will be in
the middle 70s under partly to mostly cloudy skies with moderate 
southeast winds. Low level moisture will surge across the area 
from the Gulf on Saturday, heading inland with the dryline over 
West Texas and an advancing cold front over North Texas. High 
temperatures on Saturday will warm into the 90s for all inland 
areas while staying in the mid to upper 80s along the coast. Skies
will be partly to mostly cloudy with breezy southeast winds. A 
mild sea breeze may pop up early Saturday afternoon. It will be 
partly cloudy Saturday night with light to moderate southeast 
winds as the Plains storms system tracks east, with low 
temperatures in the 70s.

A coastal flood statement for wave runup on the beaches remains in 
effect from 1 AM through 10 AM Saturday morning due to a high 
astronomical tide around 5 AM coinciding with higher than normal 
observed tides.

LONG TERM (Sunday through Friday): 500mb trough across the
midwest United States Sunday will move eastward Monday allowing a
500mb ridge to move across the central United States. A 500mb
trough is progged to move into the western U.S. Monday and move
across the Rockies Tuesday. At the surface...low pressure across 
the midwest U.S. Sunday will move towards the northeast U.S. 
Monday while low pressure develops on the lee side of the Rockies
Monday and moves into the central plains Tuesday. Rain chances
will be limited across deep south Texas Sunday through Tuesday 
with showers and thunderstorm activity remaining well to the north
of the CWA through Wednesday. By the middle of next
upper level ridge is progged to develop across the southeast U.S.
Wednesday as an upper level trough deepens across the western
United States. Low to mid level moisture will be limited across
south Texas through the rest of the forecast period as the 500mb
ridge across the southeast U.S. and northern Gulf of Mexico moves
little through Friday so nut much in the way of rain chances are

Breezy to windy conditions will develop across the CWA Monday as 
the pressure gradient increases across the lower Texas coast. A 
surface trough is expected to move into the western portions of 
the CWA Tuesday allowing the pressure gradient to weaken Tuesday 
before increasing on Wednesday. Breezy to windy conditions will 
return Wednesday as a result. Very warm to hot temperatures are 
expected on Tuesday with more of a south wind prevailing across 
the Rio Grande valley ahead of the surface trough. Heat index 
values are expected to reach 100 to 105 degrees across western 
portions of the CWA Monday and across the eastern portions of the 
CWA Tuesday. Increasing temperatures and humidity Wednesday will 
provide elevated heat index values across most of the RGV and 
northern ranchlands. 

MARINE (Now through Saturday night): Moderate to strong 
southeast winds and elevated seas will develop and persist through
the short term forecast as transient Plains low pressure systems 
periodically deepen and tighten the pressure gradient with higher 
Gulf pressure. Small craft should exercise caution conditions will
develop tonight through Saturday night, with low end small craft 
advisory conditions possible on the Gulf.

Sunday through Wednesday...Light to moderate southeast winds will
prevail across the coastal waters Sunday as surface high pressure
across the eastern Gulf of Mexico provides a weak pressure 
gradient across the western Gulf. The pressure gradient will
increase across the lower Texas coast Monday as surface low 
pressure develops on the lee side of the Rockies. Moderate to
strong southeast winds will develop across the western Gulf
Monday. Winds are expected to veer to the south Tuesday as the
surface low moves eastward into the south-central plains. The
pressure gradient will remain strong across the coastal waters
through Wednesday. Moderate to strong southeast winds will likely
continue across the lower Texas coast through Wednesday. Small
craft advisories may be needed for portions of the lower Texas
coastal waters Monday through Wednesday. 



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