Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Houston/Galveston Texas
659 PM CDT Wednesday Apr 1 2015
see 00z aviation discussion.
shortwave trough will cross the region this evening and remaining
rain showers/thunderstorms and rain activity will move NE and away from area by 02z. Forecast
soundings all rather bullish with low ceilings developing overnight.
Feel winds just off the surface favor more of a low ceilings so will
carry MVFR ceilings overnight. Ceilings will mix out between 17-19z
Thursday with VFR conds expected Thursday aftn/evening. MVFR ceilings
are expected again tomorrow night. South winds on Thursday will
remain strong and gusty. 43
Previous discussion... /issued 303 PM CDT Wednesday Apr 1 2015/
upper level short wave trough on water vapor imagery continues to
move over southeast Texas this afternoon. Radar has shown a few storms
across the area but are fairly widely scattered producing close to
a quarter inch of rainfall on average. Boundary layer remains
rather moist. Possible that thunderstorm activity will continue to
develop through the evening as the wave passes over the area.
Activity should be ending around 02-03z as the wave pushes east.
Latest rap/hrrr runs seem to be initializing with too much
convection compared to recent radar trends. Current probability of precipitation look on
track with 30/40 percent and then dropping to 20 percent tonight.
Models continue to be fairly consistent with the next frontal
passage coming late Friday. The main differences will be expected
rainfall with the front. The GFS/European model (ecmwf) look to be a bit more on
the wet side than the NAM for the 12z runs. Upper level support
looks rather weak but still a fairly strong front for early April.
Model sounding show some capping to overcome but expect
frontogentic lift to be sufficient for thunderstorm development.
Instability will be limited and combined with capping/dry air
above 700mb...not looking for much activity to develop. Suspect
there will be a thin line of showers and embedded thunderstorms to
push through with the front. Rainfall amounts look to be around a
tenth to a quarter inch.
High pressure builds over the area with a much cooler airmass for
Saturday. A strong jet streak then pushes over North Texas on Sunday.
This could bring a brief chance of rain on Sunday but think most
of the activity will be over North Texas into the arklatex. Return flow
sets up quickly as another low deepens over the North Plains in
response to another stronger trough. This system pushes east
rather quickly with no frontal passage. By Wednesday next week another
broad trough forms over The Rockies. Southern branch of the jet
becomes more active and could support active weather for mainly
North Texas. Moisture advection will again support at least some
shower and thunderstorm activity for the area next week.
moderate onshore flow expected for the next couple days. Speeds
might flirt with caution criteria at times - as early as tonight.
Will forego caution flags at this time and just go west/ 15kt and let next
shift reevaluate trends. Gradient weakens a bit early Friday in
advance of the next cold front. Expect this boundary and
associated thin line of rain showers/thunderstorms and rain to push off the coast late
Friday evening. Small craft advisories will be required in its
wake. Nearly winds will gradually veer back to the southeast early Sunday
as high pressure moves off to the east. 47
Preliminary point temps/pops...
College Station (cll) 80 67 82 68 79 / 40 20 20 10 30
Houston (iah) 81 67 83 70 82 / 40 20 20 10 30
Galveston (gls) 76 69 77 70 77 / 20 20 10 10 20