Severe Thunderstorm Warning 77, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1143 PM CDT Fri May 15 2020

.AVIATION...

A line of SHRA/TSRA will be moving through SE TX overnight, with mainly
MVFR but possibly IFR ceilings and/or visibilities. Winds will be gusty
with the stronger storms. Should see a decrease in SHRA/TSRA coverage
as the day progresses, but afternoon activity cannot be ruled out.
Wet grounds and light winds tomorrow night might result in MVFR/IFR
ceilings and visibilities to develop. 42

&&

PREV DISCUSSION... /ISSUED 425 PM CDT Fri May 15 2020/

SHORT TERM...(Tonight through Saturday Night)

Scattered to numerous showers and thunderstorms have developed
this afternoon and have already dumped 2 to 5 inches of rain
across parts of Harris County. Convection should wane within an
hour or two of sunset. A strong upper level low will sink into
Central Texas later tonight. Low level moisture will continue to
stream into the area and PW values are progged to reach 2.25
inches. The position of the upper low will create favorable upper
level winds maximizing upper level divergence. Another line of
showers and storms will approach the area from west to east
between 06-09z. SPC has outlooked most of SE TX in Slight Risk for
severe storms for late tonight and this seems reasonable based on
available CAPE and the speed of motion. The line will be racing
east at around 50 mph. he primary severe weather hazard will be
strong damaging winds. This ties into the heavy rain threat. High
PW values and strong moisture flux convergence in the 850-700 mb
layer supports heavy rainfall but the speed of motion should allow
things to move through pretty quick. Still expecting a burst of
1-3 inches of rain...locally higher possible but not expecting
excessive rain at this time. Will maintain the Flash Flood Watch
as previously configured.

What to do on Saturday? Global models are considerably slower with
the upper low and maintains high rain chances for much of the day.
Short range guidance is faster moving the upper low to the east
and less bullish with precip. The eastern half of SE TX is still
on the east side of the upper trough axis so feel showers will
still be possible for the east with perhaps some drying setting in
the afternoon from the west. Clouds and precip will keep things a
bit cooler than normal. The system should be east of SE TX
Saturday night and any residual rain will end in the evening. 43

LONG TERM [Sunday Through Next Friday]...
Expect lingering showers to persist across SE Texas through Sunday
afternoon as the upper low pushes Westward into the southeastern
CONUS. Expected rainfall totals on Sunday remain lower than what is
anticipated over the earlier part of the weekend, with totals not
expected to eclipse 1.0". A reprieve from the wet weekend comes on
Monday, as upper ridging and surface high pressure move in behind
the departing low. Expect warm temperatures and clearing skies
through mid-week, with temperatures expected to break into the mid
to upper 80s by Monday afternoon while overnight lows hover in the
upper 60s. Slightly more pleasant dew points in store as winds taper
off and shift to the north by early Monday. Onshore flow re-develops
by Wednesday night as the surface gradient tightens behind the
departing surface high. Nonetheless, weather looks to be fairly dry
heading towards the end of the work week, although the renewed
onshore flow should have things feeling pretty muggy by the
beginning of the weekend.

Cady

MARINE...

Strong inflow into todays storms coupled with expected strong
inflow into tonight's storms have prompted an SCEC for the coastal
waters and adjacent bays. This may need to be extended into
Saturday morning. The flow on Saturday becomes a bit muddled in
the wake of the morning MCS. In general, a weak onshore flow is
expected to persist through Sunday night. A weak front will cross
the region late Sunday night and winds will become N-NE on Monday.
Onshore winds will return on Wednesday and persist through the end
of the week. 43

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      69  79  68  83  65 /  80  60  30  30  10
Houston (IAH)              72  80  71  85  69 /  80  80  40  40  20
Galveston (GLS)            73  79  74  82  73 /  80  80  50  40  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Flash Flood Watch through Saturday afternoon for the following
     zones: Austin...Brazoria Islands...Chambers...Coastal
     Brazoria...Coastal Galveston...Coastal Harris...Coastal
     Jackson...Coastal Matagorda...Colorado...Fort Bend...
     Galveston Island and Bolivar Peninsula...Inland Brazoria...
     Inland Galveston...Inland Harris...Inland Jackson...Inland
     Matagorda...Matagorda Islands...Montgomery...Northern
     Liberty...Polk...San Jacinto...Southern Liberty...Waller...
     Wharton.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION through Saturday evening 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...Galveston Bay...
     Matagorda Bay...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.

&&

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>