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afdmlb

Area forecast discussion
National Weather Service Melbourne Florida
1017 am EDT Sat Jul 21 2018

Update...

Scattered showers are already developing across the western side
of the peninsula this morning. 10z cape sounding and GOES-16
total precipitable water depict a soupy airmass across most of the
area with a pretty tight moisture gradient across the Treasure
Coast. Precipitable water values range from 2.2" to 2.3" from Vero Beach
northward to 1.3" to 1.4" across southern Martin County. The
shower/storm coverage will increase with such high moisture in
place as they quickly move across the state late this morning into
the afternoon hours. Main change to inherited forecast is short-
term guidance increases moisture pretty rapidly across Okeechobee
through the Treasure Coast and have bumped up pops this afternoon
across these areas to account for this. Have also increased
showers and storms chances across the interior into Brevard County
with both the local WRF and hrrr showing pretty high coverage
across these areas.

Low-level flow will again prevent the Atlantic seabreeze from
moving inland allowing temps along the coast to top out in the low
to mid 90s. Temperatures across the interior will range from the
upper 80s to low 90s. Heat index values will be in the 100 to 105
degree range.



&&

Aviation...
VFR conditions expected outside of showers and storms. Shower and
storm coverage will increase over the interior terminals late this
morning into early afternoon and then transitioning to the coastal
sites by early afternoon. Quick movement of showers and storms
should allow things to wind down fairly early with most activity
over with for interior sites by late afternoon and ending along
the coast by early evening. Subsequent tafs will reflect this
trend. VFR conditions thereafter.



&&

Marine...

Southwesterly to west-southwesterly winds of 10 to 15 kt will
keep seas 2 to 3 feet. The offshore winds will promote eastward
moving showers and storms again today where wind gusts greater
than 34 knots, frequent lightning, and torrential downpours will
certainly be possible.



&&

Hydrology...the Saint Johns River is either above action stage or
just above flood stage between Geneva and Astor. Little change is
expected into the weekend.

Near Geneva, just south of Lake Harney, the most recent stage was
8.06 feet, which is just above flood stage (8.0 feet). The river is
forecast to fall slightly but remain near flood stage into early
next week. A river Flood Warning remains in effect for this area.

At Sanford, the most recent stage was 5.01 feet, which is above
action stage (4.2 feet). The river is forecast to remain nearly
steady, staying below flood stage (5.5 feet) into early next week.

Near Deland, the most recent stage was 3.45 feet, which is near the
threshold for action stage (3.5 feet). The river is forecast to
remain nearly steady into early next week, with perhaps a very slow
fall indicated.

At Astor, the most recent stage was 2.16 feet, which is below flood
stage (2.3 feet), but at action stage. The river is forecast to
remain at action stage but just below flood stage into early next
week.



&&

Preliminary point temps/pops...
dab 92 76 94 76 / 50 20 50 30
mco 91 77 91 77 / 60 20 50 30
mlb 93 77 94 78 / 60 20 50 40
vrb 93 76 95 76 / 50 20 60 50
Lee 89 78 91 77 / 60 20 50 40
sfb 92 77 92 77 / 60 20 50 30
orl 91 77 92 75 / 60 20 50 30
fpr 93 76 94 76 / 40 20 60 50

&&

Mlb watches/warnings/advisories...
Florida...none.
Am...none.
&&

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