FXUS64 KHGX 202320

Area Forecast Discussion
National Weather Service Houston/Galveston TX
620 PM CDT Mon Mar 20 2023

...New AVIATION...

(This evening through Tuesday Night)
Issued at 227 PM CDT Mon Mar 20 2023

Hopefully you were able to get out and be touched by some sun
earlier today, as high clouds continue to stream over Southeast
Texas, giving all of us an overcast or virtually overcast sky
early this afternoon. Meanwhile, surface winds have become firmly
southeasterly, and have increased to around 10 knots with some
folks seeing gusts in the teens or even low 20s. So, while
temperatures will struggle to rise to around 60 degrees in the
warm spots this afternoon, you can probably see how things are
lining up for much warmer conditions tonight than in recent
nights. Lovers of colder temperatures, savor every minute of
today! I`m not saying that last night was for sure the last cold
night we`ll see until the fall; but I`m definitely not going to
guarantee that we`ll see widespread lows in the 30s again anytime
soon, either.

This afternoon`s high clouds will gradually come down overnight,
settling into that 2000-3000 foot range late tonight. We can also
expect surging dewpoints on the onshore flow that is not expected
to drop off as winds typically do overnight. Instead, the surface
high over the Southeast US will create a tight pressure gradient
with a developing surface low on the Great Plains to our
northwest, keeping those winds up. Indeed, dewpoints were in the
20s and lower 30s around dawn this morning and coastal areas are
already pushing into the lower 40s with these onshore winds. We
can expect that to push upwards and inland through the night, with
all but the northeastern corner of our area looking at dewpoints
above 50 degrees. This sets a high temperature floor in which many
areas that only see highs in the 50s today but will also see lows
in the 50s tonight into tomorrow morning as well.

This moisture increase is not just restricted to the surface
layer, either. Satellite precipitable water estimates range from
0.4 inches in the northeast to around 0.8 inches in the southwest
this afternoon. Onshore flow brings in a plume of moisture pushing
precipitable water to 1.2 to 1.5 inches in the guidance for
tomorrow. Along with this, it`s plausible that we see some light
showers from the pre-dawn hours Tuesday through the day in the
maximum portion of this moisture channel, which should include at
least the western third to half of the forecast area...or roughly
west of I-45. These will be isolated to scattered, quickly moving
light showers, so any rain should be brief, light, and many will
not see rain at all.

Given the warm start to the day, we`ll be certain to see warmer
temperatures tomorrow afternoon in spite of cloud cover and light
showers. I have highs in the lower 70s for virtually the entire
area, and the warm spots west/southwest of the Houston metro will
try to break into the middle 70s. The one spot that may fail to
quite reach 70 would be up in the northeast around the Houston and
Crockett National Forests. Finally, tomorrow night, the continued
onshore flow and cloud cover will boost low temperatures up even
higher - dewpoints in the lower 60s will help keep lows in the 60s


(Wednesday through next Sunday)
Issued at 227 PM CDT Mon Mar 20 2023

Mid-week will start off warm and humid as strengthening onshore
flow continuously advects Gulf air into Southeast Texas. Even
overnight, winds won`t really decouple as a 25-35kt nocturnal jet
sets up overhead. Therefore, highs on Wednesday and Thursday will
be in the low to mid 80s while overnight lows will be in the upper
60s to low 70s. Although there will be a robust 800-700mb cap
overhead, a few light sprinkles are possible throughout most of
the day given the saturated profile beneath the cap and plenty of
isentropic lifting, leading to 10-15% PoPs on Wednesday and
Thursday. Early Friday morning, another cold front will start to
push its way through Southeast Texas with the latest suite of
global models slowing down the front`s arrival time and duration a
few hours. That being said, the bulk majority of the front will
push through on Friday afternoon and depart by late Friday
evening. We can expect scattered showers and thunderstorms with
the frontal passage and possibly a few strong storms with it. CAA
and drier air will fill in behind the front, but will be short
lived as onshore flow quickly resumes by early Sunday morning.
Therefore, highs will still reach the upper 70s ahead of the
front, but overnight lows will be noticeably colder and in the 50s
in the wake of the front. Even on Saturday, southwesterly flow
will quickly drive up temperatures and daytime highs will reach
the low 80s once again. Finally by Sunday, onshore flow and a
possible warm front ahead of the next shortwave will reintroduce
slight rain chances (15-20%) and keep daytime highs in the low


(00Z TAF Issuance)
Issued at 612 PM CDT Mon Mar 20 2023

VFR skies and SE winds will continue through the evening hours.
CIGS are expected to drop through the night, becoming MVFR by
morning. There is some uncertainty regarding the timing of MVFR
conditions. SE winds continue through tomorrow. CIGS could remain
MVFR during most or all of the day tomorrow. CIGS at the coast are
a little more tricky. Some data suggest the coast could remain VFR
through the TAF period. For now, we think the coast will join
their northern neighbors in MVFR CIGS by tomorrow morning.


Issued at 227 PM CDT Mon Mar 20 2023

Increasing onshore winds will return to the area today and will persist
into Thursday night. Caution flags have been upgraded to a Small
Craft Advisory for our nearshore and offshore waters late tonight
with Advisory conditions expected to persist through at least late
Wednesday evening. Patchy sea fog possible Wednesday and Thursday
evening, but gusty winds might limit the fog potential. The next
cold front and associated showers and thunderstorms is expected to
move into the region on Friday.


College Station (CLL)  52  72  65  82 /  10  20  10  20
Houston (IAH)  53  73  66  82 /  10  20  10  20
Galveston (GLS)  57  72  67  74 /   0  10  10  10


GM...Small Craft Should Exercise Caution through Tuesday morning for

     Small Craft Should Exercise Caution until 10 PM CDT this evening
     for GMZ350-355-370-375.

     Small Craft Advisory from 10 PM this evening to noon CDT Tuesday
     for GMZ350-355-370-375.



LONG TERM....Walts

NWS HGX Office Area Forecast Discussion