National Weather Service Raw Text Product

564 
FXUS64 KHGX 032059
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
359 PM CDT Fri May 3 2019

.DISCUSSION...
Stalled outflow boundaries have allowed for backed E/SE surface 
flow resulting in enough turning and low level shear to support 
rotating updrafts today. There is also ample moisture with PWAT 
over 1.6-1.7 inches and increasing 925mb flow to support higher 
rain rates with these strong/severe storms. This has led to 
advisory level flooding where storms moved over areas that already
had rainfall last night and yesterday. A few bayous and creeks 
have reached bankfull or are forecast to exceed banks. Water vapor
imagery shows one short wave trough about the exit the region 
which has been the trigger for today's storms. Upstream there is 
another jet streak coming into the Rio Grande Valley and is 
already causing deep convection over west central Texas. Large 
scale ascent with this jet streak should spread over SE Texas 
tonight into tomorrow morning. Given conditions already in place 
and better upper level support tonight, we decided to go with a 
flash flood watch since another 1-2 inches really quickly could 
cause at least advisory level flooding and isolated 3-4 inches 
could push for flash flood warnings. Flash flood watch covers 
areas basically along I-10 northward since these areas have seen 
the most rainfall. Harris County is included mainly because the 
northern half of the county has had quite a bit of rainfall while 
areas to the south and southeast of Harris County have had very 
little. Still quite possible some of the higher amounts could 
occur over Houston and impact bayous, underpasses and other low 
lying urban areas. As for a severe threat, it should be more 
isolated overnight and if lines of storms form, then damaging 
winds will be the main concern. This is all secondary to the 
potential for heavy rainfall. Storms should be leaving the area 
Saturday afternoon so have rain chances decreasing after 18Z 
Saturday.

Overpeck

.MARINE... 
East to southeasterly winds have been diminishing this afternoon, 
with seas following behind them. While Freeport buoy is reporting 4 
foot seas, have gone ahead and let the SCEC fall off as winds are 
down to 4 kts and season should dip below 4 feet. Showers and 
thunderstorms have mainly been over land today, but potential will 
continue tonight into Saturday. A weak boundary will stall out north 
of the coast Saturday, and winds will be out of the southwest 
Saturday morning before turning more easterly as high pressure 
settles in Saturday night. Easterly flow will continue through much 
of the day Sunday, and onshore flow returns by the beginning of next 
week. Tides are forecast to remain about a foot above normal through 
the weekend, and could potentially cause issues by early next week.

Luchs

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      66  82  63  85  65 /  90  60   0  10   0 
Houston (IAH)              69  83  66  86  67 /  90  80   0  10   0 
Galveston (GLS)            72  79  72  81  73 /  80  70  10  10   0 

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Flash Flood Watch through Saturday afternoon for the following 
     zones: Austin...Brazos...Burleson...Coastal Harris...
     Colorado...Grimes...Houston...Inland Harris...Madison...
     Montgomery...Northern Liberty...Polk...San Jacinto...
     Southern Liberty...Trinity...Walker...Waller...Washington.

GM...NONE.
&&

$$

Discussion...39