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Area forecast discussion...updated 
National Weather Service Austin/San Antonio Texas
941 PM CST Wednesday Jan 28 2015

Update...no significant updates to going forecast but did expand
patchy areas of fog farther west and north along the Rio Grande
Valley. Hourly temperatures and dewpoints were set to match
observational trends. See discussion below for more details.

&&

Discussion...many sites either reached or came within 1-2f
degrees of record highs today across the region with the warm
south winds in place. This wind direction will also help moisture
advection from the Gulf of Mexico infiltrate the region tonight and
with cooling temperatures overnight...help fog and low stratus
develop. Fog and low stratus are expected to develop near the
coast around midnight and then shift northwest across the coastal plains
and slightly up the Rio Grande Valley. Visibilities down to one
quarter mile will be possible in isolated locations but overall
visibilities should remain in the 1 to 3 sm range. As fog slowly
mixes out it could be thick enough for low cloud ceilings to
develop through middle morning before dissipating by noon.

Due to early clouds and a weak front coming through
tomorrow afternoon...high temperatures will be slightly cooler
but should still reach into the low to middle 70s. /Allen/

&&

Previous discussion... /issued 549 PM CST Wednesday Jan 28 2015/

Aviation...
VFR conditions will continue through the evening at all terminals.
Winds will drop below 10 kts after sunset. Low level moisture will
increase in Austin and San Antonio and this will lead to fog
formation by around 09z and visible will drop to IFR. Ceilings may form at
LIFR height early morning Thursday. Ceilings and visible will improve to
VFR by late morning Thursday. Drt will remain VFR through the
period. A cold front will move through the region Thursday
afternoon bringing breezy north to northeasterly winds.

Previous discussion... /issued 233 PM CST Wednesday Jan 28 2015/

Short term (tonight through Thursday night)...
temperatures this afternoon have risen into the upper 70s and will
continue to warm a few degrees into the lower 80s. South winds are
helping to drive up temperatures and will result in moisture
return overnight tonight. This will result in areas of fog and low
clouds tomorrow morning along and east of the Interstate 35
corridor. A trough over the northern plains will drag a cold front
through central Texas late tomorrow morning into the afternoon
hours. The only noticeable effect for Thursday will be a
wind shift...with winds during the afternoon out of the north
around 10 knots gusting to 20 knots. Cooler air begins to filter
into the area Thursday night with lows dropping into the middle 40s.

Long term (friday through wednesday)...
Friday will bring a change in the weather pattern as a Stout low
pressure over Baja California California will send a disturbance across the
southwest towards Texas. Rain chances begin along the Rio Grande
during the day on Friday...and increase west to east starting
Friday night. The best chances for rain will be during the 24 hour
period from sunrise Saturday to sunrise Sunday. Model precipitable
water values for this time period range from 1.0 to 1.3 inches so
some pockets of locally heavy rainfall are possible. Areas across
the Edwards Plateau and Hill Country will see the most
rain...between three quarters of an inch to an inch...while areas
east of Interstate 35 can expect a quarter to half an inch based
on the most recent model runs. Pockets of heavier rainfall could
produce up to 2 inches. Precipitation will slowly push east on
Sunday with rain chances decreasing throughout the afternoon and
evening. While the weekend will not be a total wash out...it will
for sure be a wet one. The rain will be welcome across the area as
parts of the Edwards Plateau and Hill Country are still
categorized in severe to extreme drought.

Looking at the amount of lift that will be present Saturday and
Sunday a few isolated thunderstorms are not out of the question.
The best chances for these isolated thunderstorms will be Saturday
afternoon as an 850 mb low level jet passes over and Sunday as the system
exits the region. These thunderstorms would further aid in
producing pockets of heavier rainfall.

Temperatures over the weekend will remain mild with highs in the
50s and 60s with lows in the 40s and 50s. The next front moves
through the area on Sunday ushering in cooler temperatures for
Monday followed by a slow warm up by midweek.

Models are once again in disagreement on what to do about the large
trough as it moves east from the Baja California towards Texas early next week.
Both models take it over central Mexico...but then diverge as the
GFS takes the low northeast right over central Texas and the European model (ecmwf)
keeps the low to our south over Brownsville. The GFS solution is a
very wet one adding about another inch of precipitation Monday and
Tuesday across areas east of Interstate 35. Have discounted the
GFS for now and continue to show a mostly dry forecast consistent
with the 12z European model (ecmwf) and the runs of both models from yesterday.

Treadway

&&

Preliminary point temps/pops...
Austin Camp Mabry 53 74 45 59 46 / 0 - 10 10 30
Austin Bergstrom international Airport 48 73 45 58 44 / 0 - 10 10 30
New Braunfels Muni Airport 49 74 46 59 46 / 0 - 10 10 30
Burnet Muni Airport 51 71 41 55 42 / 0 - 10 10 30
del Rio International Airport 49 75 51 59 48 / 0 - 10 20 50
Georgetown Muni Airport 53 72 43 57 44 / 0 - 10 10 30
Hondo Muni Airport 46 75 47 60 47 / 0 - 10 10 50
San Marcos Muni Airport 50 74 45 58 45 / 0 - 10 10 30
La Grange - Fayette regional 53 73 47 59 47 / 0 - 10 10 20
San Antonio International Airport 50 74 47 59 47 / 0 - 10 10 30
Stinson Muni Airport 49 74 48 60 47 / 0 - 10 10 30

&&

Ewx watches/warnings/advisories...
none.
&&

$$

Mesoscale/aviation...05
synoptic/grids...15
public service/data collection...33

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