Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Austin/San Antonio Texas
826 PM CDT Monday may 4 2015

Update... /update for new tornados watch Val Verde County/

Isolated severe storms will continue to be a threat for Val Verde
County. Recent cell trends are on the way down over southern
Terrell County...but the past few runs of the hrrr and the Texas tech
WRF still suggest regeneration and a favorable shear environment
for an isolated supercell or two toward midnight. The rest of the
forecast looks in good shape.


Previous discussion... /issued 651 PM CDT Monday may 4 2015/

Update...update for 00z aviation below.

Aviation...VFR conditions ongoing early this evening across
south-central Texas. Isolated rain showers continue across Val Verde
County...near drt. Stronger thunderstorms to the northwest may move east
into northern Val Verde County thorugh the evening. Will monitor
radar trends...and should thunderstorms trend further south may have to
amend to include mention at drt.

Otherwise...moist low level south to southeast flow will
continue...leading to MVFR ceilings re-developing 03-06z and IFR
ceilings 07-10z. Ceilings forecast to rise back into MVFR range
14-16z...potentially VFR middle afternoon on Tuesday.

Southeast winds around 15 kts this evening diminishing to around 10 kts
at Sat/ssf/aus overnight.

Previous discussion... /issued 239 PM CDT Monday may 4 2015/

Short term (tonight through Tuesday night)...
upper air analysis this morning showed a ridge extending from the
central Gulf Coast to the Central Plains...a trough over the West
Coast and split flow developing over West Texas. The 250mb jet
extended from the bottom of the West Coast trough curving
anticyclonically across northern Mexico through West Texas down
toward South Padre Island. At the surface...high pressure was
centered to the east and winds were from the southeast. Low level
moisture has increased over the last 24 hours with dew point
temperatures 3 to 10 degrees higher. The larger increases are
across the north. During this period the West Coast upper trough
will ride up over the ridge to the Central Plains. This will bring
southwesterly flow over Texas...but it will weaken as the trough
moves to the northeast. Chances for thunderstorms will move into
the region from the west tonight and spread across the area
Tuesday. Probability of precipitation will be low end chance. Storms are likely to
initiate along the dryline out West. Cape will be sufficient to
produce strong to severe storms out west and Storm Prediction Center has our western
areas in the marginal to slight risk for Tuesday. Deep layer shear
may be sufficient to support a few supercells.

Long term (wednesday through monday)...
the upper level pattern will be somewhat static through the middle
of the week as a large amplitude ridge and trough develop...the
ridge in the east and the trough in the west. This will keep
southwesterly flow over Texas. This will lead to an extended
period of slight to low end chance probability of precipitation Wednesday through Friday.
The upper pattern will become slowly progressive over the weekend
as the western trough moves toward the middle of the country.
Models are in good agreement on the trough moving across Texas
Sunday night and Monday. This will bring higher rain chances for
the weekend.


Preliminary point temps/pops...
Austin Camp Mabry 65 82 69 84 70 / 10 30 40 40 20
Austin Bergstrom international Airport 63 82 68 83 69 / 10 30 40 30 20
New Braunfels Muni Airport 64 82 68 84 70 / 10 30 30 30 20
Burnet Muni Airport 63 80 67 82 68 / 10 40 40 30 30
del Rio International Airport 68 81 70 84 70 / 40 40 30 30 30
Georgetown Muni Airport 63 81 68 82 69 / 10 40 50 40 30
Hondo Muni Airport 66 81 69 84 70 / 20 30 30 30 30
San Marcos Muni Airport 64 81 69 82 69 / 10 30 40 30 20
La Grange - Fayette regional 62 82 69 84 71 / 10 30 30 30 20
San Antonio International Airport 66 82 69 84 70 / 10 30 30 30 20
Stinson Muni Airport 67 83 70 85 71 / 10 20 30 30 20


Ewx watches/warnings/advisories...


public service/data collection...30

National Weather Service Glossary of Abbreviations