PREV DISCUSSION... /ISSUED 1059 AM CST Sun Feb 19 2017/
DISCUSSION...
Seeing a few patches of drizzle still around late this morning.
Otherwise, no showers yet. With some heating, we are likely to
see isolated showers develop later this aft, especially across nw
areas. Removed the mention of thunder for this aft. Temps are
likely to peak close to 80 inland today with mostly cloudy skies.
The main event will begin after midnight as showers/thunderstorms
approach and/or develop across western areas. Expecting widespread
shwrs/tstms slowly moving from west to east in the 2 AM Mon to
late afternoon period. Looking like there will be a flash flood
threat where we see repeated cell movement over the same areas,
especially across the SE 2/3rds of the area. We are likely going
to be issuing a flash flood watch for portions of SE Texas later
this afternoon for the time period of early Monday morning through
Monday afternoon.
PREV DISCUSSION... /ISSUED 351 AM CST Sun Feb 19 2017/
DISCUSSION...
Patchy fog and low clouds prevail early this morning. The fog is
expected to dissipate by mid morning but skies will remain
generally cloudy through the day. Could be a light sprinkle or
some drizzle this morning beneath a strong capping inversion. 850
temps remain very warm and considering the warm start to the day,
it won`t take much heating to boost high temps to 80. Limiting
factors would be the cloud cover and stronger winds. Trimmed PoPs
for today as ascent from the approaching upper trough won`t arrive
until tonight and fcst soundings show relatively dry moisture
profiles and a capping inversion in place for most of the day.
Moisture increase rapidly tonight as an upper level trough
approaches West Texas. PW values reach 1.5-1.6 inches by 09z and
1.80 inches by 12z. Fcst soundings show a saturated profile from
the sfc to 500 mb at 12z over the central/coastal zones. The GFS
dries things out over the west with very dry air moving into the
900-700 mb layer at 12z which considering the dynamics and
orientation of the moisture axis, well, it looks weird. The GFS
fcst soundings tries to dry things out quickly on Monday but with
the upper level trough axis to the west, shra/tsra likely to
persist into the mid afternoon before drying commences. The TT WRF
which performed very well on Friday maintains rain all day
Monday. Upper level winds still look very favorable as SE TX will
lie in a splitting jet at 300 mb and will also lie in a weak jet
couplet. Have added locally heavy rain to the weather grids. At
this time, it appears widespread rainfall of 1 to 2 inches with
isolated totals between 3 and 5 inches will fall across the area.
SPC has placed the western half of SE TX in a marginal risk for
severe weather for late tonight. Could get some gusty winds and
small hail but it appears the primary hazard will be heavy rain.
Drier air will work into the region Mon night and Tuesday as weak
high pressure moves into the state behind the departing upper
trough. Temperatures will remain unseasonably warm with highs in
the mid/upper 70s. Unseasonably warm temps will prevail for much
of next week as 850 temps stay warm. The air mass will be dry so
there should be a relatively large diurnal range each day. Low
pressure will develop in the lee of the Rockies on Thursday and
this system will move northeast and drag a cold front across SE TX
Friday evening. Might have enough moisture to squeeze out a
shower or two but will keep the fcst dry for now. Temps will trend
cooler next Saturday in the wake of the front. Warm air advection
next Sunday will bring a few showers and slightly warmer temps
back to the area.