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Area forecast discussion 
National Weather Service Miami Florida
131 am EDT Sat Jul 26 2014

Aviation...scattered thunderstorms are forecast to develop later
this morning and continue through the afternoon. Hrrr shows
activity developing along both coasts. So have included thunderstorms in the vicinity for
all terminals beginning late morning and continuing through early
evening. Brief IFR will be possible and will monitor radar trends
for amendments if necessary later today. Light winds will become
onshore this afternoon at 5-10 knots. Winds will be variable and
gusty in and near thunderstorms. /Gregoria

&&

Previous discussion... /issued 939 PM EDT Friday Jul 25 2014/

Update...
outside of a few minor tweaks within the gridded forecast package
based on the latest observations around the local area...no major
updates are anticipated as the previous forecast package remains
on track. The storms that have developed along the boundary
extending northward across inland Broward and Palm Beach counties
should begin to diminish through the late evening hours. The best
chance for overnight showers will remain over the adjacent
Atlantic waters. 85/ag

Previous discussion... /issued 733 PM EDT Friday Jul 25 2014/

Aviation...
VFR conditions to prevail at all sites through the next 24 hours
outside of any thunderstorms. Mainly east-southeast winds should persist
overnight before becoming light and variable. A few storms are
lingering mainly across interior portions of Miami-
Dade...Broward...and Palm Beach counties tonight due to boundary
interactions. These storms are weakening and should stay away from
the East Coast sites. Southeast flow to return tomorrow afternoon
with a Gulf Breeze at kapf.

Previous discussion... /issued 214 PM EDT Friday Jul 25 2014/

Short term (tonight-Sunday night)...
deep layer ridge currently stretches across South Florida into the
Atlantic with another strong ridge over the Southern Plains.
Sandwiched in between these two highs is a weak trough and this has
caused some destabilization to the airmass across South Florida this
morning. This will create a more active afternoon for thunderstorms
than yesterday but the steering flow will keep most activity inland
away from the coasts. However, steering flow is nearly parallel to
the coasts so some convection will fire up just inland from the
coasts before the sea breezes push the activity well inland. Much
drier air aloft is currently located across the central Bahamas, and
in the circulation around the base of the ridge will begin to move
into South Florida on Saturday and especially on Sunday. The GFS is
much faster with the leading edge of the drier air with the NAM not
showing it to reach the southeast coastal area until late Saturday
afternoon. Still, the forecast soundings are showing precipitable water lowering
to around 1.5 inches during the course of the day and this will
limit the overall coverage of thunderstorms. The atmosphere will
remain very unstable however with plentiful low level moisture so
scattered storms over the interior will still be anticipated. The
steering flow will be more easterly but at 5 miles per hour or less so some
storms could again form just inland from the coasts before pushing
to the interior areas. The models are in good agreement that the
driest air will arrive by Sunday with forecast soundings showing
precipitable water down to less than 1.2 inches so activity will be much less. The
500mb temperatures are also depicted to warm back to around -5 to -
6c which also will act to limit thunderstorm development.

Long term (monday-friday)...
a strong and deep middle/upper level trough will develop across the
eastern U.S. Next week with a cold frontal boundary entering North
Florida by Tuesday or Wednesday. This set up will likely destabilize
the airmass over South Florida once again although neither the GFS
nor European model (ecmwf) show significant cooling aloft at this time and neither
increase moisture substantially. So it remains uncertain at this
time just how much influence this system will have on South Florida
but the steering flow will turn more south to southwest with the
interior and East Coast having the better chances for the
thunderstorms.

On a side note, there is a Saharan dust layer (sal) across the
Caribbean and the central Atlantic. The models keep most of this to
our south and east but are showing a diffuse part of it reaching
southeast tip of the peninsula late this weekend or early next week.
No major effects are expected although it could make the sky appear
hazier than normal.

Marine...
tranquil marine conditions will continue with a light east to
southeast wind less than 15 knots and seas of 2 feet or less.

&&

Preliminary point temps/pops...
West Palm Beach 78 90 78 91 / 20 20 20 20
Fort Lauderdale 80 91 80 92 / 10 20 10 30
Miami 80 91 79 93 / 10 20 10 30
Naples 77 90 77 92 / 20 20 10 20

&&

Mfl watches/warnings/advisories...
Florida...none.
Am...none.
GM...none.
&&

$$

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