Flood Watch 5, NWS Miami, FL

Area Forecast Discussion
National Weather Service Miami FL
754 PM EDT Wed Sep 30 2020

.Update...
Remnant convection lingers just along the coastline and the near
shore waters of Palm Beach, while a few showers are still shown
on radar across the Miami metro area. With the frontal boundary
stalling right over SoFlo, will keep inherited POPs/Wx grids, as
new Model blend is once again going below ongoing trends, which
are better align with HURR/global models.

Best chances for rain and/or isolated storms remain over the
Atlantic metro areas and the southern-most portion of the state.
And with the front being shown as basically lingering over us
during the next day or so, expect more showers on Thursday and
likely on Friday.

&&

.Aviation...
Periods of MVFR are still possible for the rest of tonight across
the Atlantic terminals, but most significant convection is now
moving over the coastal waters. Winds will remain mostly NE
through around 14Z, then ENE for Thursday afternoon. Another round
of showers/TS also expected after 14Z with a lingering frontal
boundary across the area.

&&

.Prev Discussion... /issued 337 PM EDT Wed Sep 30 2020/

Short Term (Now through Thursday)...
A stalled frontal boundary is currently over the region and should
remain overhead through the short term period. Visible satellite
imagery shows this feature well with more sunshine occurring to the
south and east (upstream) of the cold front with more low level
cloudiness. A line of showers has developed early this afternoon in
response to the front. At this juncture it would appear the best
potential for rainfall through the afternoon and early evening hours
will be across the Atlantic metro...basically Homestead to Boca
Raton and east. CAMs also shows this scenario with HRRR coming in
just a bit more robust with precip/T'storm chances that prior runs.
Although the front is not forecast to move much, if convection
slightly behind the front develops, mesoscale boundaries (outflow)
may move the front a bit more downstream with time.

Showers and storms will weaken overnight except for the immediate
coast. Otherwise, generally northerly or northeasterly winds can be
expected. The boundary will remain in place through Thursday and in
fact Thursday looks fairly similar to today. Models are picking up
on a bit better QPF signal across the interior portions of the state
and Atlantic coast. Again, there will be at least a limited hydro
concern across the metro. In fact, WPC has delineated a marginal
risk of excessive rainfall for the region on Thursday and with PWATs
in the 2.2"-2.4" range, can't argue with that assessment.
Temperatures will range from around 90s across the southern areas to
middle and upper 80s during the afternoon up around the Lake
Okeechobee region.

Long Term...

Friday through Sunday...

Wet and unsettled weather will continue through the extended
period as broad mid-upper level troughing encompasses the eastern
half of the CONUS. At the surface, the quasi-stationary boundary
draped across the region will ever-so-slowly inch northward
through the weekend, keeping South Florida under the influence of
northeasterly flow in the lower levels and south/southwesterly
flow aloft. Therefore, sufficient tropical moisture will remain
through the atmospheric column, in fact, model derived PWATs
values remain in the 2.1 to 2.4 inches range over the region,
translating to a potential flood risk. Current experimental PQPF
indicate rainfall totals of 1 to 3 inches are possible across
South Florida, with higher accumulations of 4 to 6 inches
potentially over the eastern metro areas. Thus, the main concerns
are currently for the east coast, where several days of antecedent
rainfall could accumulate over flood prone areas.

While highly uncertain at this time, additional moisture could
work it's way into the area from a tropical low that currently has
a 10 percent chance of development in the next 2 days and a 60
percent chance of development in the next 5 days from the National
Hurricane Center. Current model iterations depict the
aforementioned low moving west-northwest into the Yucatan
Peninsula this weekend. However, if the low keeps more eastward
into the Yucatan Channel and NW Caribbean Sea, then additional
tropical moisture could become lofted into South Florida, leading
to greater coverage of rainfall across the region.

Monday through Wednesday...

Regardless of the outcome of the low that NHC is currently
monitoring, the overall synoptic pattern will remain favorable for
scattered showers and thunderstorms to continue each day across
South Florida next week. Although, the lows evolution will
certainly be something we will continue to monitor with each model
run and as we get closer in time. Greatest coverage of convection
next week will be focused over the interior and west coast of
South Florida with flow returning out of the east.

Marine...
A cold front across the region will continue to bring northerly or
northeasterly winds through the remainder of the workweek before a
more easterly transition takes shape this weekend. Outside of the
potential for scattered showers and storms, wind and seas should
remain somewhat favorable through Friday. On Saturday pressure
gradient begins to increase, especially over the Gulf waters as a
surface low develops across the western Caribbean.

Aviation (18z Aviation)...
Despite the close proximity to a cold frontal boundary, mostly
MVFR/VFR conditions expected this cycle. Some isolated to scattered
showers or T'storms may develop, especially today through early
evening. Brief VIS/CIG reductions may be possible with storms or
perhaps with low stratus just behind the front late tonight.
Otherwise, expect light northerly winds through the cycle.
&&

.Preliminary Point Temps/PoPs...
West Palm Beach  75  87  74  85 /  40  70  50  60
Fort Lauderdale  77  89  76  86 /  40  70  50  70
Miami            77  89  76  86 /  40  70  50  70
Naples           72  87  73  84 /  20  50  40  50

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
GM...None.
&&

<!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>