#545 Postby weatherdude1108 » Fri Aug 19, 2016 4:19 pm
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
403 PM CDT FRI AUG 19 2016
.SHORT TERM (Tonight through Sunday)...
...Flash and river flooding becoming an increasing concern this
weekend due to heavy rainfall potential...
Focus will center on the weekend time frame where widespread heavy
rain could lead to flash and river flooding across the Rio Grande
Plains, Southern Edwards Plateau, and portions of the Hill
Country. Highest rainfall amounts in this area will likely be in
the 4-6 inch range with isolated totals up to 10 inches Saturday
morning through Monday morning. The most significant time frame
for the heaviest rainfall appears to be Saturday evening through
mid-day Sunday. The hazardous weather outlook as been updated to
reflect this increasing risk and updated graphics have been posted.
For today, isolated showers are ongoing across the Coastal Plains
with additional activity near the Val Verde/Mexico border. The
Plains activity will wane into the evening but activity our west
will persist through much of the evening and overnight. Pockets of
heavy rainfall could occur with 1-2 inches possible. Showers
should weaken through early Saturday morning but will shift east
into the Hill Country and towards San Antonio.
The ingredients for a heavy rain and flooding impact event will
begin to come together late Saturday afternoon as a weak boundary
sags south towards the Hill Country. A tropical airmass will be in
place as 2-2.4 PWATs and 0-1km 16 g/kg mixing ratios will be in
place with several lifting and low-level convergence mechanisms to
generate heavy rainfall. A mid-level Pacific tropical wave will
merge with a weak trough in this moist environment coinciding with
the surface boundary near the Hill Country vicinity through Sunday
morning. Positive southerly flow theta-e advection and increasing
low-level flow will likely aid in ample moisture supply into
these lifting dynamics. All-told, this can result in pockets of
very heavy rainfall and storm training amounting to 4-6 inches
with pockets up to 10 inches. The main model consensus of heaviest
rainfall keeps the highest totals west and north of the Metro
areas. However, both Austin and San Antonio could see 2-4 inches
over the entire weekend. The EC is farther north and east with
highest rainfall totals with GEM over the Hill Country and
GFS/NAM closer to the South Edwards Plateau and Rio Grande Plains.
The going rainfall graphics online are a consensus of these
signals with slightly stronger weight towards the GFS/NAM/GEM
given their run-to-run evolutions.
River and creek flooding could be a substantial risk across the
Rio, Nueces, Frio and possibly the upper reaches of the
Guadalupe, Medina, Pedernales rivers through the weekend and into
early next week.
&&
.LONG TERM (Monday through Friday)...
Rain coverage will decrease Sunday night into Monday morning but
scattered showers and storms should still linger given continued
mid- and upper-level weak divergence and south flow still feeding
into the boundary stalled north of the area. Additional showers
and storms are expected Monday but should be more scattered in
nature. These however, could still worsen flooding issues from
the weekend rains. Tuesday should have even less coverage to only
the Coastal Plains as the boundary washes out north and the area
remains in a subtle mid-level weakness. Sub-tropical ridging will
slowly build into the area Wednesday through late week with only
some coastal sea-breeze showers.
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The preceding post is NOT an official forecast, and should not be used as such. It is only the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For Official Information please refer to the NHC and NWS products.
I could do without rain for several days(7 in a row with the least amount 0.40", highest 4.25"), but really don't want the heat to come back!!
