Tornado Warning 24, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
637 PM CDT Tue Apr 12 2022

.AVIATION [00Z TAF Issuance]...

MVFR ceilings will settle in overnight with coastal areas like GLS
and LBX lowering to IFR overnight. Frontal passage tomorrow with
some showers expected ahead of the front and then with the frontal
passage. These showers could become TS by the afternoon as it
pushes towards IAH and south, but should be out of our area by 03Z
tomorrow. Winds quickly become northerly in its wake.

Lenninger

&&

.PREV DISCUSSION /Issued 422 PM CDT Tue Apr 12 2022/...

.SHORT TERM [through Wednesday Night]...

Widespread cloud cover will continue this afternoon as southerly
flow filters warm and more humid air into the region. In fact, sfc
dew points have increased into the upper 60s to low 70s.  This
influx of low level moisture combined with mid-level forcing due to
passing shortwaves and steep lapse rates are allowing for the
development of showers and storms mainly along islands and Gulf
waters. The main story continues to be the potential for strong to
severe storms this evening. The environment continues to be
favorable for strong thunderstorms with strong SBCAPE, steep mid-
level lapse rates (7-8C/km) and deep layer shear (~35-40 knots).
However, latest soundings and hi-res models suggest a strong capping
inversion persisting over SETX; thus, any convective updrafts
will need to overcome this cap, at least for this afternoon. Will
continue to keep an eye out to our west where discrete convective
storms are beginning to blossom along a dryline. Additional
development is anticipated along and ahead of this dryline as the
main mid-upper level trough over central TX moves north-
northeast this evening. Hi-res models such as the HRRR, RAP and
FV3 bring discrete updrafts developing close/west of the Brazos
Valley between 6 - 10 PM this evening. If storms do develop, the
main threats will be isolated hail (soundings depict decent
instability in the hail growth zone), damaging winds (DCAPE ~ 1000
J/kg). An isolated tornado will also be possible. For areas
farther east, and basically most of our CWA, the risk for severe
weather decreases this evening as capping remains strong and
forcing weakens.

A lull in precipitation is expected late tonight before a pre-
frontal boundary approaches the region early Wednesday morning. A
broad area of theta-e advection will remain over the region, leading
to showers and isolated thunderstorms along and ahead of the FROPA.
Uncertainty in strength and coverage of this activity is high as it
will strongly depend on the this evening's convection. As of now,
if storms develop on Wednesday, the greatest threat for strong to
severe storms looks to remain across our northern counties. In
terms of the timing of the FROPA, have leaned towards the
NAM/ConsALL, bringing the front by late Wed afternoon/early
evening. Behind the front, a drier airmass filters in with north-
northwest winds and mostly clear skies.

In terms of temperatures, with persistent southerly sfc flow and 850
mb temperatures in the upper teens, highs will range mainly in the
80s on Wednesday.

05

.LONG TERM [Thursday Through Tuesday]...

Dry/mild weather will prevail across SE TX on Thurs in the wake of
the Weds night cold front. With NE/E winds around 10 mph in place,
highs will be in the lower to mid 80s...with lows ranging from the
upper 50s over our northern CWA to the lower and mid 60s elsewhere.
However, we're still looking for a quick turnaround with winds and
moisture levels as a warm front moves inland on Fri. This boundary
could trigger a few showers and possibly isolated thunderstorms as
it moves across the CWA during the day.

Isolated/widely scattered rain chances are progged to continue Sat
and Sun as the nearly stationary warm front lingers across the FA.
Confidence is not too high with regards to development so did keep
with 20-30% POPs. Long-range guidance remains very unsettled with
the pattern starting Sun with regards to the next cold front. The
ECMWF and Canadian are continuing with FROPA around Sun night/Mon
morning with moderate NE winds and drier air moving into the area
for the start of the week. On the other hand, GFS seems to be con-
tinuing with onshore winds, deep moisture and rain chances for SE
TX through Sun and most of Mon; with the front coming in from the
back door late Mon/early Tue. So given all this uncertainty, will
be keeping the current POPs/temperatures as is for now. 41

.MARINE...

Based on observations/trends this morning, did add Galveston Bay
to the Small Craft Advisory earlier today. There were reports of
gusts up to 45-54kts near the storms moving E/NE parallel to the
coast across the Gulf waters. The SCA for GLS Bay will remain in
place until tomorrow afternoon...same as the SCA for our coastal
waters. Along with the strong gusty winds, other hazards for to-
night/early tomorrow morning to include elevated seas along with
scattered strong to severe thunderstorms.

Winds are forecast to briefly shift to the NE/E by tomorrow/Weds
night as a weak front moves off the coast. Light to moderate off-
shore winds to prevail Thurs with onshore winds returning Fri as
a warm front pushes inland. This moderate SE flow (with elevated
seas) should persist through the weekend. Another wind shift (to
the east or northeast) will be possible Mon as another weak cold
front moves across the region. 41

&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL)  70  89  52  85  59 /  20  30   0  10  10
Houston (IAH)          72  85  59  83  63 /  20  40  10  10  10
Galveston (GLS)        72  80  66  76  69 /  20  30  20   0  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...High Rip Current Risk through Wednesday evening for the
     following zones: Bolivar Peninsula...Brazoria
     Islands...Galveston Island...Matagorda Islands.

     Small Craft Advisory from 1 PM to 7 PM CDT Wednesday for the
     following zones: Brazoria Islands...Galveston
     Island...Matagorda Islands.

     Coastal Flood Advisory until 7 AM CDT Wednesday for the
     following zones: Bolivar Peninsula...Brazoria
     Islands...Galveston Island...Matagorda Islands.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION through Wednesday afternoon
     for the following zones: Matagorda Bay.

     Small Craft Advisory until 1 PM CDT Wednesday for the following
     zones: Galveston Bay.

     Small Craft Advisory until 7 PM CDT Wednesday for the following
     zones: Coastal waters from Freeport to Matagorda Ship
     Channel TX out 20 NM...Coastal waters from High Island to
     Freeport TX out 20 NM...Waters from Freeport to Matagorda
     Ship Channel TX from 20 to 60 NM...Waters from High Island
     to Freeport TX from 20 to 60 NM.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
541 PM CDT TUE APR 12 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1040 AM     NON-TSTM WND GST 5 NE GALVESTON          29.28N 94.83W
04/12/2022  E62 MPH          GALVESTON          TX   BROADCAST MEDIA

            A POWER POLE WAS DOWNED ALONG WITH SEVERAL
            POWER LINES. GUST WAS ESTIMATED FROM NEARBY
            KGLS ASOS OBSERVATION AT 1039 AM.

&&