Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Angelo Texas
403 am CST Sat Dec 20 2014
(today and tonight)
We currently have a mix of low clouds and fog across the area
this morning. Most of the area is just dealing with low clouds,
but Crockett, Irion, and parts of Sterling County have had areas
of fog, some of it dense at times. We are addressing the fog with
nowcasts for now, as low clouds continue to expand to the
northwest. These clouds should reduce the coverage of the fog that
has developed, but this will be watched closely, and a dense fog
advisory may be issued later.
So, while we will start with these low clouds in place, it is a
relatively thin layer of moisture, and so we should see some
breaks in the low clouds on the western edge as we move into the
afternoon hours, similar to yesterday. With breaks expected later
today, we should see warmer temperatures as well, and have kept
the warmer temperatures inherited with minimal changes. No
significant changes to the overnight forecast either, with lows
expected to drop into the lower 40s. Southerly flow should be a
little more organized tonight, helping to reduce the possibility
of fog, so will leave the mention of fog out of the forecast,
although some patchy fog could develop again as temperatures will
be falling to or near the dew point once again.
(sunday through friday)
Low cloudiness across some of west central Texas early Sunday
morning will clear out mid/late morning, with low-level flow veering
to the southwest and drier air advecting into our area. Temperatures
will be warmer Sunday with highs expected to be in the 60-65 degree
An upper trough will deepen over the plains and Midwest Sunday
night and Monday, and associated cold front will push south
across the Red River Monday afternoon. Looks dry and warm south
of this front across our area. Have increased highs into the lower
to mid 70s given the forecast pattern, with west-southwest low-
level flow and associated downsloping effects and 850 mb
temperatures climbing to 14-16 degrees c. Should have an increase
in high cloud coverage during the day to limit temperatures from
climbing much further than currently anticipated. Going with mid
to upper 60s for highs across our far northern counties, where the
cold front should arrive by late afternoon.
The cold front will advance south across the rest of west central
Texas Monday night. The aforementioned upper trough is progged to
deepen a bit further into Texas Monday night, with a disturbance
moving into its base. Lift and moisture look sufficient to support
low pops for showers across our northern counties Monday night.
Gusty north winds will follow passage of the cold front and continue
into the day Tuesday. Temperatures will be much cooler Tuesday with
highs in the lower to mid 50s. Some cloud cover is expected,
especially in the morning. Temperatures are forecast to drop into
the lower to mid 30s for lows Tuesday night with radiational
cooling, as surface high drops south across West Texas.
Dry conditions with a warming trend expected Wednesday and Thursday,
with the flow aloft over Texas transitioning from northwest to
west. Temperatures look well-above normal for Christmas day when
forecast highs (in the 70s) could be similar to what occurs Monday.
The 00z GFS and European model (ecmwf) differ with handling of an upper trough
moving out of the northwestern part of the U.S. During the middle
to late part of next week. Despite these differences, both models
indicate a dry cold frontal passage across our area late Thursday
night/early Friday morning.
Preliminary point temps/pops...
Abilene 53 41 62 44 71 / 0 5 5 5 5
San Angelo 58 41 65 44 75 / 0 0 5 5 5
Junction 58 39 62 42 73 / 5 5 5 5 5