Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Austin/San Antonio Texas
936 am CDT Friday Oct 31 2014
the shower and thunderstorm complex that moved overnight across
south central Texas is now over the crp area. A cold front just
behind these storms is now located across the southern counties
and will exit our area within the next hour or two. Skies will
become mostly sunny to sunny for the afternoon with highs in the
lower 70s across The Hill Country and upper 70s across the Rio
Grande plains. A cool night is expected for the trick or treat
activities with overnight lows dropping to the 40s most areas.
Previous discussion... /issued 643 am CDT Friday Oct 31 2014/
cluster of rain showers/thunderstorms and rain with IFR/MVFR ceilings/visibilities will continue to
move to the south and out of south central Texas by 15z. VFR skies
will prevail today through Saturday morning. VFR level ceilings will
persist through much of today along the Rio Grande plains...
including kdrt...as moisture will be slower to erode there.
Otherwise...only few100. North to NE winds 10 to 20 kts will prevail with
gusts to 25 kts today as surface high builds into area...decrease
to less than 10 kts as surface high settles over area and then
shift to east Saturday morning as surface high moves off to the east.
Previous discussion... /issued 329 am CDT Friday Oct 31 2014/
Short term (today through saturday)...
showers and thunderstorms have increased in coverage ahead of the
cold front overnight. The scattered to numerous showers and storms
stretches from The Hill Country southeast into the coastal plains.
This activity is expected to continue to push south for the
remainder of the overnight hours and into the morning hours before
leaving the County Warning Area sometime around 9-10 am. The current VAD wind
profile shows easterly flow in the lowest 5 km of the atmosphere.
This is what some of the high-res models where showing which is
leading to a greater amount of moisture pooling ahead of the
frontal boundary. Radar has estimated up to 1-2 inches of rain
has fallen in some areas out of the stronger storms and this
trend will likely continue as the activity progresses south.
Current instability levels will continue to support thunder...but
nothing too strong.
Behind the front...much cooler temperatures and drier air will
filter into the region. Skies should clear out by trick or treat
time with temperatures in the 60s falling into the 50s for most of
the area by 9 PM. Winds will be out of the north around 5 to 12
miles per hour.
Southerly flow will return by Saturday afternoon...but not before
lows bottom out in the 40s for much of the area. Some 30s will be
possible in The Hill Country. Highs Saturday will only top out in
Long term (saturday night through thursday)...
the Fall weather will be short lived as deep southerly flow brings
back moisture and warmer temperatures beginning on Sunday. The
return flow is in response to the next approaching system which is
expected to be over the western Continental U.S. By Sunday afternoon. This
system has been the topic of conversation as of late and will
continue to be so over the next several days. Models have had a
hard time with this system but will most likely continue to
improve once the low gets over land and can be sampled by the
upper air network. The latest runs of the medium-range guidance
are in a little better agreement but still have large discrepancies
with the timing and evolution of the low. The GFS keeps the main
parent trough progressive which sends a front into the area
Tuesday. The European model (ecmwf) is not quite as strong with the middle-latitude
trough but does still bring a front through...although 12 hours
later and stalls it near our southern zones. The GFS then comes
more in line with the Euro and cuts off a fairly strong low from
the parent trough and slowly meanders it near our County Warning Area through
Friday. The Euro cuts it off but moves it north of the area by
Thursday night and Friday.
While confidence is low in the Wednesday-Thursday forecast...
confidence continues to increase with the Tuesday and Tuesday
night forecast. We should see a frontal boundary enter the County Warning Area
Tuesday and at the same time strong upper lift associated with the
main longwave trough and increasing Pacific moisture will all
converge over south-central Texas. It is still too early to get
into the specifics of where the frontal focus will be at what time
and if and where it stalls...but there continues to be increasing
confidence that a widespread heavy rain is possible for the area.
It is too early to get into how much rain will fall...but some
locations could see around 2-3 inches. If the front stalls...or
the upper low stalls or meanders near the area...the expected
totals could increase. We will continue to fine tune this forecast
as the event nears...stay tuned.
Preliminary point temps/pops...
Austin Camp Mabry 75 45 66 47 75 / 0 0 0 0 -
Austin Bergstrom international Airport 76 40 66 44 74 / 0 0 0 0 -
New Braunfels Muni Airport 77 45 69 46 76 / - 0 0 0 -
Burnet Muni Airport 71 41 64 46 72 / 0 0 0 0 -
del Rio International Airport 76 51 70 56 73 / 10 - 0 - -
Georgetown Muni Airport 73 41 64 44 73 / 0 0 0 0 -
Hondo Muni Airport 78 41 70 49 73 / 10 0 0 - -
San Marcos Muni Airport 77 43 68 44 75 / - 0 0 0 -
La Grange - Fayette regional 76 43 67 43 74 / - 0 0 0 -
San Antonio International Airport 77 48 70 50 76 / - 0 0 0 -
Stinson Muni Airport 78 47 71 49 78 / 10 0 0 0 -
public service/data collection...32