Tornado Warning 12, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
353 PM CDT Fri Apr 28 2023

...New SHORT TERM, LONG TERM, MARINE...

.SHORT TERM...
(This evening through Saturday Night)
Issued at 351 PM CDT Fri Apr 28 2023

The immediate concern continues to surround the approach of a cold
front, along with an associated line of strong thunderstorms, this
evening. Convection has developed this afternoon within the warm
sector of a developing surface low ahead of the advancing boundary
approximately 70 miles to the northwest of Brazos/Burleson Counties.
The line of storms is expected to advance to the southeast over the
remainder of the afternoon and into the evening and environmental
conditions favor a continued threat of strong to severe storms.
Latest SPC Mesoanalysis indicates a robust axis of 2000-3000 J/kg of
sfc based instability roughly across locations west of I-45, in
addition to widespread swaths of effective shear in excess of 50 kt.
Forecast soundings indicate the presence of stronger convective
inhibition present to the east of the 45 corridor thanks to the
persistence of a low-level inversion at around 850mb.

We anticipate the line of storms to reach the Brazos Valley within
the next 1-2 hours, where the hail and wind threat will be greatest
given the aforementioned environmental conditions. An isolated
tornado, which has already been observed along the line previously,
cannot be ruled out given the highly favorable shear profile. Timing
for the greater Houston metro looks to be roughly between  7-9 PM
with the line clearing the coast before 11PM. Some lingering showers
may persist into the morning.

With the boundary itself following the advancing line of storms,
winds will shift to the north overnight and increase in strength
tomorrow, with gusty conditions prevailing throughout the course of
the afternoon. As advection brings cooler and drier air to the area,
clouds should gradually clear from south to north over the course of
the day. Highs tomorrow will struggle to eclipse 70 while overnight
lows will dip all the way into the upper 40s to lower 50s for most
locations. Winds will relax as the surface gradient weakens,
resulting in winds reaching 5-10 mph by the end of tomorrow night.

Cady

&&

.LONG TERM...
(Sunday through next Thursday)
Issued at 351 PM CDT Fri Apr 28 2023

Dry/cool quiet weather to prevail Sun/Mon as SE TX remains under the
influence of surface high pressure and a building ridge aloft. At/to
slightly below normal temperatures on Sun (with highs in the low 80s
and lows in the 50s) should be trending slightly warmer on Mon (with
highs in low to mid 80s and lows in the low 60s) given the return of
onshore winds. But even with E/SE winds in place through much of the
week, moisture levels could remain limited across the region (as per
this latest air mass moving well into the Gulf), so may have to keep
an eye on NBM temps going forward as they could run a bit cooler. At
any rate, low rain chances (~20%) are on tap to return by the end of
the week as the weakening upper ridge allows for the approach of em-
bedded disturbances in the southern stream jet from the west. 41

&&

.AVIATION...
(18Z TAF Issuance)
Issued at 1253 PM CDT Fri Apr 28 2023

The main forecast concern in the current period surrounds the
approach of a cold front this evening, along with an associated
line of strong thunderstorms. Ahead of the front's arrival, SE
winds will increase slightly and potentially reach 20+ knots later
this afternoon. The line of storms ahead of the front should reach
CLL at around 2300Z, pushing southeastward towards IAH/HOU at
0100-0200Z and GLS by 0400-0500Z. Strong wind gusts and hail are
possible with this line of storms, particularly for terminals NW
of the I-610 loop. Lingering showers are possible as the frontal
boundary itself moves through the area before sunrise, with
moderate to strong NW winds developing behind the front. Gusts as
high as 30kts are possible tomorrow afternoon, with MVFR cigs
clearing to VFR and skies eventually becoming clear over the
course of tomorrow morning.

Cady

&&

.MARINE...
Issued at 351 PM CDT Fri Apr 28 2023

Onshore winds will continue to increase the rest of this afternoon on
into this evening ahead of a line of strong (possibly) severe thunder-
storms moving in from Central TX. This line should reach the Upper TX
coast by this evening (estimated timing is between 5-9 PM)...then mov-
ing through our Gulf waters overnight. Strong N/NW winds are expected
to develop in the wake of its associated cold front and have upgraded
the Gale Watch to a Gale Warning starting overnight through tomorrow.
Frequent gusts to gale force and rapidly building seas should prevail
through much of the day Saturday. Conditions will be gradually improv-
ing by Saturday night as high pressure builds into the state. As this
high weakens/shifts east, light to moderate southeast winds as set to
return to the area by Mon. 41

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)	  54  70  48  81 /  80  10   0   0
Houston (IAH)			  58  70  51  83 /  70  20   0   0
Galveston (GLS)			  61  72  59  78 /  50  30   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Gale Warning from 4 AM to 7 PM CDT Saturday for GMZ330-335-350-
     355-370-375.

&&

SHORT TERM...Cady
LONG TERM....41
AVIATION...Cady
MARINE...41