Preview of NWS' New Version of Forecast
This preview is not operational and should not be used for support decisions.

Area Forecast Discussion (AFD)

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

FXUS64 KBRO 170855

Area Forecast Discussion
National Weather Service Brownsville TX
355 AM CDT Fri May 17 2019

.SHORT TERM (Now through Saturday): Mid level ridge axis overhead 
this morning will gradually move east by tonight as a 500 mb trough 
approaches from the west. High temperatures today will range from 
the lower 80s along the beaches to the low to mid 90s inland under a 
mix of sun and clouds. The pressure gradient will begin to 
strengthen today as surface low pressure across the Plains interacts 
with high pressure across the Gulf of Mexico. Moderate to breezy 
southeast winds are expected today and Saturday. Low temperatures 
tonight will fall into the low to mid 70s under partly to mostly 
cloudy skies. A frontal system across the central U.S. along with a 
dryline across Texas on Saturday, will provide showers and 
thunderstorms across the Plains extending south into central Texas. 
Most of the convection across Texas will move east during the day on 
Saturday and should remain well north of the CWA. However, will 
continue to mention a slight chance of showers and thunderstorms 
across the northern ranchlands for Saturday. High temperatures 
Saturday will mainly be in the low to mid 90s, with a few upper 90s 
possible near Falcon Lake.  

A coastal flood statement remains in effect for wave runup on the
beaches through 7 am due to a high astronomical tide coinciding 
with higher than normal observed tides.

.LONG TERM (Saturday Night through Thursday): Generally, the long 
term period looks like a typical summer pattern in Deep South 
Texas, with highs into the 90s through next week. A series of low 
pressure systems will work through the Plains this weekend into 
next week, strengthening the pressure gradient, increasing 
southerly winds, and boosting high temperatures Sunday into 
Wednesday especially. With the increase in moisture at low levels 
due to stronger onshore flow, expect muggy nights through 
Thursday, with low temperatures only dipping into the mid and 
upper 70s, well above normal for mid May. 

A strong front will sweep across the Plains and northern Texas on 
Sunday, with little in the way of a frontal passage expected 
across South Texas. The next front sweeps across the Plains and 
northern Texas on Tuesday, also likely missing Deep South Texas, 
but potentially nudging into the northern ranchlands before
stalling or falling apart. Have kept all POPs through the long 
term at 10 percent or less at this time, with strong and dry 
southwesterly flow aloft expected to cap off any convective 
initiation. That being said, the best chance of any isolated 
thunderstorms each day would occur across old boundaries 
interacting with the seabreeze on Monday, any ongoing convection 
that can survive this far south near the front on Tuesday, or old 
boundaries and seabreeze interaction Wednesday afternoon. 

Heat Index values may top 100 degrees across the Rio Grande Valley
Sunday afternoon through Wednesday afternoon, with Monday 
afternoon potentially nearing Heat Advisory criteria across 
portions of the upper valley, in Starr and Zapata counties. Mid 
90s to near triple digit heat, coupled with increased low level 
humidity, could create dangerous conditions during the heat of 
the day for anyone exposed. Typical heat safety messaging would 
apply this week. Remember to check on your elderly friends, 
family, and neighbors. Make sure your pets or livestock have shade
and plenty of water. 


.MARINE (Now through Saturday): Moderate to occasionally strong 
southeast winds and building seas will prevail across the lower 
Texas coastal waters through the period as the pressure gradient 
strengthens. Small craft should exercise caution on the Laguna Madre 
and nearshore Gulf waters today due to increasing winds and seas. 
Small craft advisories will likely be needed for the Laguna Madre 
and the Gulf waters on Saturday.

Saturday Night through Thursday: A series of low pressure systems
work the Plains over this weekend into mid next week, strengthening
the pressure gradient along the lower Texas coast, increasing 
onshore flow, and creating hazardous marine conditions across 
coastal waters. Light to moderate winds and seas on Sunday give 
way to moderate to strong southeasterly winds Monday and Tuesday.
For now have kept wind gusts just shy of gale force on Monday
night, with Small Craft Advisories likely needed into Tuesday. 
Small Craft Advisory conditions may continue Wednesday through 
Thursday across offshore Gulf of Mexico waters, especially during 
the afternoon hours with moderate winds. Small Craft Advisories 
for Wind appear likely Monday and Tuesday across the Laguna 
Madre, and may be possible during the afternoon hours of Wednesday
and Thursday.


BAYVIEW/PORT ISABEL  86  77  87  77 /  10  10  10  10 
BROWNSVILLE          89  78  90  78 /  10  10  10  10 
HARLINGEN            90  76  92  77 /  10  10  10  10 
MCALLEN              93  77  95  77 /  10  10  10  10 
RIO GRANDE CITY      93  75  97  76 /   0  10  10  10 
SOUTH PADRE ISLAND   80  78  82  77 /  10  10  10  10 




This product is also available on the web at:

63-Caceres...Short Term/Aviation
56-Hallman...Long Term
67-Mejia...Upper Air/Public Service