Area Forecast Discussion
Issued by NWS Brownsville, TX
FXUS64 KBRO 240547 AAB
Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
1247 AM CDT WED AUG 24 2016
.DISCUSSION...Updated for latest aviation discussion below.
.AVIATION...Mostly clear skies and light southeast winds prevail
across deep south Texas early this morning. VFR conditions
expected to continue through the next 24 hours as a mid level ridge
continues overhead and provides subsidence across deep south
Texas. Light southeast winds overnight will become moderate to
breezy across the area by mid morning.
.PREV DISCUSSION... /issued 639 PM CDT TUE AUG 23 2016/
DISCUSSION...Updated for latest aviation discussion below.
AVIATION...Satellite images and surface observations indicate
mostly clear skies across most of the CWA early this evening.
Ceilings were near 5500ft at KHRL. Expect VFR conditions to
prevail this evening through early Wednesday morning as the 500mb
ridge across the northern Gulf of Mexico extending into south
Texas continues to provide subsidence across the CWA.
PREV DISCUSSION... /issued 239 PM CDT TUE AUG 23 2016/
SHORT TERM (Tonight through Wednesday Night): A tropical wave
moving across the Bay of Campeche and onto the coast of East
Mexico is generating showers and thunderstorms to the south of the
CWA. Not expecting much activity this far north, but a few showers
could sneak into the area. Thus, maintained the inherited forecast
of no mentionable rain chances in the short term. Some high
cloudiness may also push north tonight and early Wednesday.
Otherwise, an H5 ridge will continue over the Southeast, and
underlying high pressure centered over the mid-Atlantic states and
extending south to the Northeast Gulf will influence the short
term even as it fades slowly to the east and north. Some continued
gradient tightening will be possible Wednesday due to enhancement
from lower pressure over North Central Mexico up to West Texas and
the Southern High Plains. The lower pressure will be due partly to
mid level troughing farther upstream and perhaps also due to
thermal low deepening. Overall, slightly warmer than normal
temperatures will continue locally, with Wednesday afternoon mid-
Valley heat index readings from 103 to 108 degrees or so. Look for
low cloud development Wednesday morning followed by scattered to
broken afternoon skies with moderate and gusty southeast quadrant
LONG TERM (Thursday through Tuesday): Longer term forecast begins
with the dominant H5 ridge nudging back westward across East
Texas. The ridge center will move off to the northeast by Friday,
drawing the strength of the ridge away from south Texas. This will
open the door for a larger surge of moisture into the region for
the weekend. Weak sfc trough into across the western Gulf will
loosen the local pressure gradient, allowing the seabreeze to
sharpen up each afternoon starting as early as Friday. With this
improved llvl focusing mechanism, showers and thunderstorms will
have an easier time developing along the seabreeze over the
weekend. Motion will still be great enough to keep the risk of any
flooding to a minimum, leading to mainly splash-and-dash showers
into early next week. Have left the rain chances nearly where they
were, with best chances closer to the coast. Later model solutions
are divided, significant differences due to the effects of the
tropical wave in the western Atlantic. Will hold on to some slight
rain chances into early next week as moisture does not look to
decrease significantly during that time.
Now through Wednesday night...High pressure centered over the north
central Gulf of Mexico will produce light to moderate southeast to
south winds and low to moderate seas. Isolated streamer showers will
be possible, mainly overnight.
Thursday through Sunday: Winds and seas will begin to lower for
most of the period as the pressure gradient across the western
Gulf weakens. Winds will generally remain around 10 knots, which
will keep offshore swells below 3 feet, and keep the chop on the
Laguna light. An increase of showers and thunderstorms is
expected for the weekend as an influx of moisture arrives around
the eastern ridge. Rain chances will remain highest during the
overnight hours, with decreasing chances later each morning.
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