Scientific Forecaster Discussion
fxus64 kewx 242020
Area forecast discussion
National Weather Service Austin/San Antonio Texas
320 PM CDT Fri Mar 24 2017
Short term (tonight through Saturday night)...
Pacific front/dry line was near the I-35 corridor mid afternoon.
Dry slotting has occurred across the southern I-35 corridor. Farther
northeast aircraft soundings near aus indicate the mid level cap
weakening. There is still a window through late afternoon and early
evening where a strong to marginally severe storm or two could form
across the ewx County Warning Area near and east of U.S. 77. However the better
threat this afternoon and into tonight will be northeast of the area.
A secondary push/front will move into the area after midnight.
The latest few hrrr runs were showing the possibility of convection
developing along this boundary overnight across the far eastern County Warning Area.
In addition, with the initial front/dry line slowing down there will
be a window for fog late tonight across the far southeast counties
before the secondary push of drier air arrives. Sunny and dry on
Long term (sunday through friday)...
a progressive pattern will occur through the upcoming week. On
Sunday a weak shortwave will pass through the Southern Plains. A warm
front looks to come back into the County Warning Area Sunday morning and then a dryline
gets dragged east into the western County Warning Area Sunday afternoon. This will
lead to a warm day, especially across the southwest County Warning Area where highs
could climb into the mid 90s. Upper 80s to low 90s are expected
elsewhere. A weak cold front looks to enter the area Monday and
results in highs a degree or two cooler.
Models are then consistent with an upper level low digging into The
Four Corners Tuesday and a rapid moisture return taking place across
south central Texas ahead of it on Tuesday. Isolated to scattered
showers and storms are possible during the day on Tuesday, favoring
central and western areas of the County Warning Area. This upper level low is
forecast to dig slightly farther south into Texas than the current
system, coming out into west central Texas Wednesday morning.
South central Texas becomes placed in a favorable location Tuesday
night into Wednesday morning, with a diffluent flow aloft between
the upper level low to the northwest and sub-tropical jet streak
just to the south. As large scale ascent spreads into the area late
Tuesday night through Wednesday morning both the GFS and European model (ecmwf) are
indicating showers and storms increasing in coverage, especially
across The Hill Country and I-35 corridor Tuesday night and along and
east of I-35 Wednesday morning. There are hints that a heavier band
of rainfall could occur near and east of I-35. Ingredients may come
into play for locally heavy rainfall but too soon to determine exact
amounts and locations. There could also be a threat for severe storms
as an organized convective complex may try and develop.
The area looks to eventually get dry slotted Wednesday afternoon from
west to east. GFS is a little more robust with mid level moisture
wrapping around the upper level low Wednesday night and Thursday and
is generating some quantitative precipitation forecast. Have retained some low pops across the
northeast half of the County Warning Area during this time.
Dry conditions on Friday and then both the GFS and European model (ecmwf) indicate
another upper level system possibly impacting the County Warning Area just beyond
winds have been a little slow to respond but in the past hour have
begun to see winds increasing across the western Hill Country and
Edwards Plateau. There will be a window now though sunset where
occasional wind gusts to around 25 mph could occur across Edwards and
Val Verde counties and possible as far south as Kinney County. Relative humidity
values are currently bottoming out around 8-15 percent and should the
winds become gusty this will result in a critical fire danger. Will
allow the red flag warning to remain in place until 7 PM.
Preliminary point temps/pops...
Austin Camp Mabry 55 81 58 87 63 / 0 0 0 10 20
Austin Bergstrom Intl Airport 51 81 55 87 62 / 0 0 0 10 20
New Braunfels Muni Airport 52 82 56 87 62 / 0 0 0 10 10
Burnet Muni Airport 50 78 56 85 58 / 0 0 0 10 20
del Rio Intl Airport 53 84 57 91 57 / 0 0 0 0 0
Georgetown Muni Airport 52 79 55 86 61 / 0 0 0 10 20
Hondo Muni Airport 49 86 56 90 59 / 0 0 0 - 10
San Marcos Muni Airport 53 82 56 87 63 / 0 0 0 10 10
La Grange - Fayette regional 59 80 57 86 66 / 20 - 0 10 20
San Antonio Intl Airport 53 84 58 88 62 / 0 0 0 10 10
Stinson Muni Airport 53 83 58 88 62 / 0 0 0 10 10