Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Houston/Galveston Texas
400 am CDT Sat may 30 2015
at 3 am...a cold front extended from about Oklahoma City to
Abilene to Fort Stockton. Rain showers/thunderstorms and rain continue to develop along the
front as it surges south...and pushes east a bit more slowly.
Satellite derived precipitable water values show 1.6-1.9 inches across southeast
Texas. Forecast soundings show convective temperatures around 82 degrees.
Upper level winds are broadly divergent and are prognosticated to remain
divergent through Sunday morning. Southeast Texas will briefly lie in a
right rear quadrant Saturday night. Rain showers/thunderstorms and rain will begin to develop
along the coast between 15-17z as temperatures warm into the lower 80s.
The cold front over North Texas will be pushing south and east and
will reach the northern zones about 18z. The sea breeze will begin
to work inland during the afternoon as the front continues to push
south and the two features should merge over southeast Texas during the
afternoon. The NAM 12 is very aggressive with the sea breeze/front
colliding around 21z with very heavy rain developing along the
U.S. Highway 59 corridor. The NAM is producing 3-4 inches of rain
across Harris...Brazoria and feet Bend counties. The quantitative precipitation forecast output from
the GFS and European model (ecmwf) are more benign but they are basically on the
same Page with a weak sea breeze merging with the cold front. Will
maintain the Flash Flood Watch as is but feel the threat for
excessive rain will focus over the central zones. Think the watch
will be trimmed from the north toward evening once convective
trends become clear.
The front will meander over the southern half of southeast Texas
through early Sunday morning. The combination of the front and a
trough at 500 mb will lead to additional showers overnight into
Sunday. Drier air will work into the area Sunday afternoon and
rain chances will decrease during the afternoon.
The upper level trough will push east on Monday but it looks
close enough to still trigger a few afternoon rain showers/thunderstorms and rain over the
eastern zones on Monday. Upper level ridging will build across south
Texas Tue-Fri. Subsidence from the ridge should limit rain chances
and allow temperatures to warm to near 90 degrees by the end of next
winds and seas may briefly get to above caution levels with
thunderstorms later today and tonight. A frontal boundary is
forecast by the models to move off the coast later tonight or on
Sunday. The front is then forecast to dissipate as high pressure
builds into the northwestern Gulf into the middle week period.
Preliminary point temps/pops...
College Station (cll) 84 67 81 64 85 / 70 50 30 10 20
Houston (iah) 86 70 83 66 87 / 80 70 50 20 30
Galveston (gls) 81 75 81 74 81 / 50 50 50 30 30
Texas...Flash Flood Watch from 1 PM CDT this afternoon through Sunday
morning for the following zones: Austin...Brazoria...