Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Austin/San Antonio Texas
544 am CST sun Nov 17 2019
all sites currently VFR. Low ceilings have developed in The Hill
Country and spreading. MVFR conditions for San Antonio sites later
this morning before becoming VFR. There is also a chance for fog
formation at Sat/ssf but more likely that fog will remain south of
terminals. A weak front will pass through the area, shifting the
winds from the southeast to north this afternoon.
Previous discussion... /issued 352 am CST sun Nov 17 2019/
Short term (today through monday)...
the current weather pattern shows a short wave trough
axis moving through the Central Plains, while down to the southwest
near baja an upper low is hanging off the Pacific coast allowing for
upper level moisture to stream across Texas. We are already seeing
some good upglide out over the western County Warning Area according to the models
(290k surface) and some low clouds are starting to form as seen by
infrared satellite. Look for this cloud area to expand in the predawn hours
and last into the early morning for the central and west central
zones including The Hill Country. Have input mention of patchy fog
across the southern half of the area. The central U.S. Trough will
push a weak boundary through our County Warning Area this afternoon out west and into
the remainder of the area by this evening. Ahead of the front, some
light southerly winds are expected. The weak surface high that will
fall in behind the boundary will basically reinforce the nice airmass
we have had for an additional day or two before we get a better
influx of southerly winds and increasing moisture ahead of the baja
upper low. Should get a fairly steady stream of mid and high clouds
as well today from the west.
With good northwest flow aloft behind this Central Plains wave, the weak
surface high will move off to the southeast fairly quickly bringing a return
of southerly winds over west and central zones on Monday. Less clouds
for Monday due to the drier downsloping northwest mid level winds.
Long term (monday night through saturday)...
the combination of the baja upper low and a stronger trough that will
be digging south along the California coast will bring better southerly flow
into the state mid week. As a result expect a steady warmup and
increasing dewpoints mid week. The deeper California low should kick out or
partially absorb the baja low. Regardless of the model, most show
some short wave energy moving overhead to give US at least a small chance
of rain on Wed. The GFS is more aggressive in taking the deeper
upper low across the Southern Plains at the end of the
week...clearing out next weekend. The European model (ecmwf) is much slower with the
upper low and keeps clouds and rain chances into at least Saturday.
At some point there will be a cold front pushing through early
Fri...but it is not from the Arctic region so even after its passage
temps will be only slightly below normal. A blend of the timing
differences looks to be the best way to handle the pop issue late in
the forecast period as of right now.
Preliminary point temps/pops...
Austin Camp Mabry 69 44 70 48 75 / 0 0 0 0 0
Austin Bergstrom Intl Airport 70 43 70 46 76 / 0 0 0 0 0
New Braunfels Muni Airport 69 45 70 47 75 / 0 0 0 0 0
Burnet Muni Airport 67 40 69 45 74 / 0 0 0 0 0
del Rio Intl Airport 72 46 73 50 77 / 0 0 0 0 0
Georgetown Muni Airport 68 41 69 47 75 / 0 0 0 0 0
Hondo Muni Airport 72 46 73 48 77 / 0 0 0 0 0
San Marcos Muni Airport 70 43 70 46 76 / 0 0 0 0 0
La Grange - Fayette regional 69 45 70 47 75 / 0 0 0 0 0
San Antonio Intl Airport 70 47 71 50 75 / 0 0 0 0 0
Stinson Muni Airport 70 48 71 50 75 / 0 0 0 0 0