Special Weather Statement, NWS Melbourne, FL

Area Forecast Discussion
National Weather Service Melbourne FL
405 AM EDT Thu Apr 6 2017

.DISCUSSION...

...Tornado Watch #131 is in effect until 800 AM for Lake/Volusia/
Seminole/Orange Counties...

...Strong to severe storms will drop south to around I-4 by sunrise,
then through the rest of east central Florida by early afternoon...

...Turning much cooler and drier tonight into this weekend...

...Increasing Fire Weather Danger through late week...

Current...Pre-frontal squall line extends from JAX to GNV to the
Gulf Coast near CGC and is pushing rapidly east toward northern
Lake/NW Volusia Counties. Inherited timing for storms still looks
good, reaching the northernmost CWA by 500 AM, the I-4 corridor by
700 AM, MLB-Lake Kism 9-10 AM, and across the Treasure Coast/Lake O
region from late morning through about 1-2 PM. This is an obvious
case for a ZFP pre-first period to address widespread shower/storm
coverage through sunrise.

Rapid storm motion vector of around 40-45KT should readily mix down
stronger updrafts, with damaging winds and hail probably in a few
cells. 0-1KM SRH expected to reach 200-300+M2/S2 over the northern
half CWA, with better storm dynamics weakening post-sunrise, but
still supportive of strong storms into the mid-late morning.

Current wind speeds fall a bit below Lake Wind Advisory criteria,
however this will be a trend to watch behind the front as it begins
to clear the area during the mid-late morning.

Cold front sweeps through the area immediately behind the squall
line passage, clearing conditions out, and signaling the onset of a
much cooler/drier air mass taking hold across the region. Maxes
today range from the U70s north to the U80s south. Widespread mins
in the L50s tonight, with some U40s across the far north and M50s
along the Treasure Coast.

Friday-Saturday...Post frontal hi pres ridge will drop into the Lwr
MS Valle/GOMex, then will build arcs the Deep South. This will
generate a deep lyr N/NW flow that will push a much cooler/drier
airmass into FL with fcst PWat values dropping to 0.25"-0.50".
Breezy conditions due to a tight sfc/low lvl pgrad on Friday will
prevent max temps from climbing out of the L70s. Winds will subside
as the pressure gradient weakens on Friday night into Saturday
morning. Clear skies and diminishing winds will allow strong
radiational cooling to occur...min temps dropping into the L/M40s, a
solid 15F blo avg.

Winds will shift to the N/NE on Sat as the high pres ridge begins to
build off the eastern seaboard. Despite a dvlpg onshore flow, the
northerly winds will continue to push cool/dry air into central FL.
Highs on Sat in the M70s will only be a 2-3F degs warmer than Fri.
Sat night temps still blo avg, but a few deg warmer than Fri night
as winds gradually shift to the E/NE and push ocean modified air
onshore. Still...min temps in the U40/L50s interior and L/M50s along
the coast will be 5-10F blo avg.

Sunday-Wednesday...Onshore flow will dvlp on Sun as the ridge center
lifts well north of the area...pushing ocean modified air acrs the
state. Temps recovering to near climo avg on Sun with maxes in the
U70s/L80s, mins U50s/L60s. Slgt chc of nocturnal coastal shras along
the Treasure coast late in the fcst pd as moisture lvls recover.

&&

.AVIATION...Made some small tweaks on the order of about 1hr to
TEMPO TS groups in the 06Z TAF set, mainly for the central and
southern aerodromes. Will need AMDs for any stronger convective
cells that moves directly across the aerodromes. DRWP data does
not yet support any mention of LLWS but will continue to monitor.
Gusty SW winds ahead of the front will shift to W-WNW later today.

&&

.MARINE...Today-Tonight...no changes at all needed to the timing
or configuration of the SCA for winds. Offshore wind component for
most of the event will keep peak seas around 6FT, with perhaps a
small area of 7FT seas well out toward 60NM north of the the Cape.

Friday-Friday night...Hazardous boating condition to cont as the
post frontal ridge builds over the Deep South/GOMex, maintaining a
moderate to fresh NW breeze. Limited fetch length due to the
offshore component will keep seas in the 3-4FT range along the
immediate coast, 5-7FT offshore and in the Gulf Stream. The
persistent offshore component will result in rough, short pd wind
chop with dominant wave pds AOB 6sec nearshore and 7-8sec offshore.

Saturday-Saturday Night...Winds diminishing gentle to moderate N
breeze thru late aftn, then a light to gentle NE breeze overnight as
the high pres ridge builds over the eastern seaboard. Seas subsiding
to 2-3FT nearshore and 3-4FT offshore by midday, then 2-3FT areawide
overnight.

Sunday-Monday...High pres ridge will build over the W Atlc early
next week, generating a gentle to moderate E/NE breeze.  Sun thru
day as high pres build over the W Atlc. Seas 2-3FT areawide Sun,
building to 3-4FT on Mon as the easterly flow begins to push a small
swell component into the east FL coast.

&&

.FIRE WEATHER...

A brisk W/NW flow will dvlp behind a cold front today that will
push a dry/stable airmass into central FL. Bulk of the dry air not
anticipated until aft sunset this evng, but aftn RH values btwn 30-
35pct will be psbl over the interior from Osceola Co. northward for
4-6hrs with sfc winds near 15mph. Latest ERC values abv 27 may drop
a few points as a prefrontal squall line pushes through the I-4
Corridor this mrng. However, given its rapid eastward motion, total
QPF will largely be 0.25" or less. Will let the red flags fly due to
as instantaneous criteria will not be hard to meet.

Steady NW sfc/transport flow will continue into Fri, resulting in a
strong dry air advection pattern. Aftn min RH values dropping to 30-
35pct areawide for 6-8hrs with sfc winds near 15 mph. ERC values are
high enough to warrant a fire weather watch given these conditions.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  76  52  69  45 /  30   0   0   0
MCO  80  53  71  45 /  40   0   0   0
MLB  82  55  71  45 /  50   0   0   0
VRB  84  55  72  45 /  50   0   0   0
LEE  76  51  71  44 /  20   0   0   0
SFB  79  52  72  45 /  30   0   0   0
ORL  80  53  71  46 /  40   0   0   0
FPR  85  54  72  45 /  50   0   0   0

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...Tornado Watch until 8 AM EDT this morning for Coastal Volusia
     County-Inland Volusia County-Northern Lake County-Orange-
     Seminole-Southern Lake County.

     Red Flag Warning from noon today to 6 PM EDT this evening for
     Inland Volusia County-Northern Lake County-Orange-Osceola-
     Seminole-Southern Lake County.

     Fire Weather Watch from Friday afternoon through Friday evening
     for Coastal Volusia County-Indian River-Inland Volusia
     County-Martin-Northern Brevard County-Northern Lake County-
     Okeechobee-Orange-Osceola-Seminole-Southern Brevard County-
     Southern Lake County-St. Lucie.

AM...Tornado Watch until 8 AM EDT this morning for Flagler Beach to
     Volusia-Brevard County Line 0-20 nm.

     Small Craft Advisory for winds from 8 AM this morning to 4 AM
     EDT Saturday for Flagler Beach to Volusia-Brevard County
     Line 0-20 nm-Sebastian Inlet to Jupiter Inlet 0-20 nm-
     Sebastian Inlet to Jupiter Inlet 20-60 nm-Volusia-Brevard
     County Line to Sebastian Inlet 0-20 nm.

     Small Craft Advisory for winds until 4 AM EDT Saturday for
     Volusia-Brevard County Line to Sebastian Inlet 20-60 nm.

     Small Craft Advisory for winds until 4 AM EDT Saturday for
     Flagler Beach to Volusia-Brevard County Line 20-60 nm.

&&

SHORT TERM/AVIATION...Cristaldi
LONG TERM/IMPACT WX....Bragaw

<!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>