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 160958

Area Forecast Discussion
National Weather Service Brownsville TX
358 AM CST Sat Feb 16 2019

.SHORT TERM (Now through Sunday): A fairly zonal 500 mb pattern 
will prevail across TX today with most of the better PVA located 
well north of the region. The 00z BRO sounding shows pretty 
limited moisture levels in place over the RGV last night and early
this morning. So expect nil pops today and tonight. The 
persistent low level WAA today and tonight will maintain temps 
well above normal for mid Feb. A series of 500 mb short waves 
moving across the Rockies and the central Midwest Sat Night and 
Sun will push a cold front through the RGV on Sun. Decent CAA in 
the wake of this fropa will lower down the high temps on Sun 
closer to Feb climo. Some decent moisture levels pool over the RGV
ahead of this approaching cold front. This will produce some 
better conv chcs across the RGV on Sun.

Will lean closer to the warmer GFS/ECMWF numbers for the short term 
forecast period as believe that the NAM may be underestimating the 
expected warmup this morning.

Will include some areas of fog across the region this morning. At 
this point the fog formation has been a bit lighter versus 
yesterday. So do not anticipate a Dense Fog Advisory across the 
inland areas this morning. 

The more SE low level flow today will tend to suppress the 
potential downsloping heating effect on the daytime highs today. 
So do not expect any record highs reached or exceeded today.

.LONG TERM (Sunday Night through Friday): The next Pacific NW
trough continues to drop into the Desert SW and deepen into mid 
week, with little to no movement expected over the next week.
The frontal boundary from early Sunday hangs around across the SE
US and northern Gulf of Mexico, with persistent low pressure 
along the boundary and lower Texas coast keeping the long term 
rather unsettled. Models have stayed relatively consistent on the 
pattern, yet differ on the smaller intricacies across Deep South 
Texas as each bout of low pressure spins by the coast and frontal 
boundary. Latest runs have spun up the initial coastal low on 
Monday, with rain chances holding off until Monday evening. After 
Monday night, light rain persists along the coast into early 
Thursday, with isolated pops into Friday. 

Temperatures rebound near normal on Monday, but struggle to gain
any further, with increasing clouds, moisture, and stiff NE winds.
While the models have trended warmer for Tuesday, due to a surface
low near the border potentially picking up southerly winds, have
opted to keep temperatures tampered slightly, as this feature
could vary quite a bit over the next 3 days. A return to
increasing NE winds and continued overrunning situation yields
cooler temperatures on Wednesday still, with some improvement
expected Thursday and Friday, allowing temperatures to gradually
warm. Models have begun to show the trough heading toward the
Midwest next weekend, finally clearing the pattern with an
associated cold frontal passage across Deep South Texas. 


.MARINE (Now through Sunday): A general light to moderate SE 
surface wind flow will prevail across the lower Texas coastline as
surface ridging remains in place over the Gulf of Mex. The low 
level flow will then shift around from the northeast to north late
Sun which may build up the Gulf seas a bit. However, no SCA 
conditions expected through Sun. 

Sunday Night through Friday: Marine conditions may become 
hazardous early Monday as coastal low pressure begins to spin up.
SCAs likely by Monday afternoon continue into Tuesday before 
lighter winds allow conditions to improve slightly. By Wednesday, 
NE winds pick up and agitate seas once again into Thursday with 
SCA conditions possible. Winds and seas begin to improve late in 
the week prior to a cold frontal passage next weekend. 


BAYVIEW/PORT ISABEL  80  67  74  60 /  10  10  40  20 
BROWNSVILLE          82  69  78  61 /  10  10  30  20 
HARLINGEN            83  68  79  58 /  10  10  30  10 
MCALLEN              87  69  81  59 /  10  10  30  10 
RIO GRANDE CITY      92  68  83  57 /   0  10  20  10 
SOUTH PADRE ISLAND   76  65  70  61 /  10  10  40  20 


GM...Dense Fog Advisory until 9 AM CST this morning for GMZ150-155.



This product is also available on the web at:

60-Speece...Short Term/Aviation
56-Hallman...Long Term
67-Mejia...Upper Air/Public Service