Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 271120

Area Forecast Discussion
National Weather Service Houston/Galveston TX
620 AM CDT Mon Mar 27 2017

Satellite trends show the potential for breaks in the MVFR deck
this morning, especially from about KCXO northward and
northwestward. An outflow boundary evident on satellite may work
its way southward past KCXO and KIAH before returning back
northward later this afternoon. This boundary should become a
focus for at least isolated showers and thunderstorms during the
mid afternoon to early evening period -- mainly between 21Z and
02Z. The Canadian model actually shows potential through about 03Z
over KUTS and KCLL.

Any MVFR decks in place should lift after 15Z today, and VFR
ceilings are possible through the afternoon. With light
southeasterly winds off of the Gulf of Mexico, MVFR is possible
tonight after 03Z with a chance for IFR or lower after about
07-09Z tonight.



.PREV DISCUSSION... /ISSUED 416 AM CDT Mon Mar 27 2017/

Some strong storms moved through Brazos county overnight with
some large hail reported but the radar is looking more benign at
the current time. At the surface, a weak area of low pressure over
central OK will move NE and drag a cold front into central Texas
later today. The front will likely stall west of the CWA by mid
afternoon. At 850 mb, a trough of low pressure extended from
southern KS into west central Texas. At 300 mb, A weak upper
level disturbance was noted over the western high plains with a
splitting jet over NE TX. The trough at 850 mb will move east
today and the tail end of the feature will linger over E-SE TX
this afternoon. Although fcst soundings not showing a lot of
moisture, have some concerns that the trough coupled with daytime
heating could trigger a few showers and thunderstorms this
afternoon. Fcst soundings show a weak cap this morning eroding by
late aftn and convective temps between 83-85 degrees. Will
maintain lowish PoPs for mainly this afternoon.

Tuesday will be relatively tranquil. Convective temps warm into
the upper 80s and fcst soundings show a dry moisture profile with
multiple capping layers. It all goes down hill late Tuesday night
into Wednesday.

PW values increase rapidly early Wednesday and should range
between 1.70 and 1.90 inches by Wed aftn. A deep upper low will
move toward the Texas panhandle with the upper flow showing a nice
split over East Texas. Fcst soundings show CAPE values between
1500-2500 J/Kg, LI values around -8, steep lapse rates and
helicity values around 115 m2/s2 over the south and over 300 m2/s2
over the north. It should be fairly active with severe storms
possible. SPC has outlooked all of SE TX for Wednesday and all
hazards look possible. Fcst soundings also show saturated moisture
profile so even though the system will be moving and storm motion
looks quick, some spots will get some locally heavy rain. The
upper level system will move slowly east Wed night/Thursday but a
disturbance rotating around the upper low will probably produce
additional rain late Wed night into early Thursday before drying
commences later in the day. Quiet weather and mild to warm temps
expected Thursday aftn through Saturday as weak high pressure
settles over the southern plains.

Another upper low will move into the Texas panhandle over the
weekend and sfc low pressure will develop over south Texas.
Moisture level increase to between 1.70 and 2.00 inches late
Saturday through Saturday night. Favorable jet dynamics coupled
with the higher moisture will once again lead to high rain chances
next weekend. Some disagreement between the GFS and the ECMWF on
how quickly next weekends system will exit the region so have
split the timing differences and will carry PoPs through Monday.

Onshore winds will weaken a bit today before strengthening tonight
and Tuesday. Advisory conditions are expected to develop at least
over the Gulf waters on Wednesday as a storm system moves across the
state. A frontal boundary will then move off of the coast by early



College Station (CLL)      84  67  85  68  79 /  10  10  10  20  80
Houston (IAH)              84  69  85  71  82 /  30  10  10  10  80
Galveston (GLS)            82  72  81  74  80 /  20  10  10  10  60




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