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LONG TERM (Wednesday through Monday)...
The latest round of model guidance continues to suggest an active
weather pattern will be in place across south central Texas for the
mid-week period, especially Wednesday evening into Thursday morning.
The main concern continues to be focused on heavy rainfall.

South-southeast flow in the lower-levels of the atmosphere will be
well-established across south central Texas on Wednesday. We will see
plenty of moisture from the Gulf of Mexico move northward across the
region with 850mb dewpoints ranging from 14-19C through Wednesday
morning. Meanwhile, the remnants of tropical system Pamela will be
moving north-northeastward across central Mexico. Near the surface,
the leading edge of a weak Pacific front will likely be stalled
somewhere across the southern Edwards Plateau and Hill Country
region. With the stalled front, plenty of moisture and daytime
heating, we should see scattered to numerous showers and
thunderstorms develop over the above mentioned regions during the
afternoon hours. By mid evening Wednesday, the models suggest the
remnant surface low associated with Pamela will move out of
northeast Coahuila Mexico into south central Texas. The exact path
and speed of this surface low remains in question, but will no doubt
serve as a focus for heavy rainfall generation Wednesday evening into
Thursday. Precipitable water values will be very close to
climatological maximums for this time of year and with soundings
showing deep moisutre and tall, skinny CAPE profiles, efficient
rainfall producing showers and storms are guaranteed. While we will
continue to see changes in subsequent model data, our main time
period of concern will be Wednesday evening into Thursday for areas
along and west of the Interstate 35 corridor. Widespread 2-5" amounts
are expected and we will certainly see localized amounts much higher
than this, especially near the remnant circulation of Pamela.

Rain chances should begin to decrease from west to east by late
Thursday afternoon. However, as mentioned above much will depend on
just how quickly the remnants of Pamela shift northeast of the
region. For now, we will keep a slight chance for showers and storms
along the Rio Grande, with rain chances in the 30-60% range farther
east into the I-35 corridor. Moisture levels do begin to drop on
Friday, but with a fairly stout cold front moving in from the
northwest and southwesterly flow aloft, we will keep a chance of
showers and storms in the forecast for most areas Friday. If the cold
front moves through quicker (GFS model), rain chances may need to be
reduced in the afternoon hours across the Hill Country and into the
I-35 corridor.

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