Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 281749
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
149 PM EDT Sun May 28 2017

.AVIATION...
VFR conditions prevailing at all sites. The sea breeze is somewhat
slow to push through the Atlantic terminals with background
westerly winds. However expect it will push through most sites in
the 19-21Z time frame before washing out. Light and variable winds
tonight before light southwest winds after sunrise. Gulf sea
breeze is through Naples and will push in again midday tomorrow.
Any showers this afternoon should stay over the interior away from
terminals. Late tonight, will need to watch for fog/smoke near
FXE/OPF due to an ongoing brush fire northwest of these sites.
Left this out for now due to low confidence but will continue to
monitor.

&&

.PREV DISCUSSION... /issued 1027 AM EDT Sun May 28 2017/

UPDATE...
A toasty start to this Sunday with temperatures expected to keep
rising. Current forecast captures trends well and only minor
updates were made to the hourly grids to bring them into slightly
better alignment with observed trends. Smoke from a wildfire in
northwest Broward County has been lingering over much of western
metropolitan Broward and Miami-Dade Counties this morning.
Conditions should be improving over the coming hours as the
Atlantic sea breeze pushes inland and the morning inversion is
overcome by diurnal heating. If any convection initiates, it
appears the best chances for showers and thunderstorms remains
over interior portions of Miami-Dade. Heat index values above 95
can be expected across much of the area today with some areas
peaking above 100. The current forecast captures all of these
aspects well, so no further updates are anticipated. Have a
wonderful Sunday!

PREV DISCUSSION... /issued 423 AM EDT Sun May 28 2017/

Record Heat Possible Today with Heat Index Over 100F...

DISCUSSION...
Short-Term (Today through Tuesday): high pressure aloft will spread
over Florida today, leading to greater subsidence over South Florida
and helping to deliver another hot day to South Florida. Will continue
established trend of going slightly above most of the model temperature
guidance as 1000-850 mb thicknesses this afternoon are expected
to be higher than yesterday, over 1430 meters across a large part
of the interior and as far east as the western suburbs of SE Florida.
Therefore, we should be able to exceed yesterday`s max temperatures
by at least 1-2 degrees most places, meaning daily record highs
in the mid 90s are well within reach at Miami, Fort Lauderdale and
West Palm Beach (see climate section below for details). Interior
sections will be in the mid to upper 90s, with one or two of the
typically warmer spots in the Everglades nudging close to 100F.
Heat index values will once again hit 100-105 degrees from midday
through at least mid afternoon. The SW Florida Gulf coast will be
the only area to not experience the record heat as a seabreeze
most of the day will keep high temperatures in the upper 80s to
around 90. Nighttime temperatures won`t provide much relief,
particular east coast metro areas where lows will barely drop
below 80 by sunrise Monday. A bit more relief interior areas
around Lake Okeechobee where lows will drop to around 70.

The high pressure area will gradually move east of the peninsula on
Memorial Day, which will introduce a shift to E/SE wind flow. As a
result, sea breeze onset across metro SE Florida may be earlier than
previous days and help limit the duration of temperatures in the 90s
(along with a perhaps few more clouds from late afternoon inland
convection). The axis of highest thickness values and hottest
temperatures will therefore shift west to interior sections as well
as west of Lake Okeechobee where more upper 90s are expected. The
Gulf coast will remain the "coolest" location with a seabreeze by
midday keeping highs from exceeding 90 degrees. Heat index values
will once again top 100 degrees most areas by midday.

The high pressure retreats far enough east by Tuesday for the SE
flow to become established. Afternoon showers and thunderstorms may
be a little more widespread Tuesday as moisture increases some, and
the moderating influence of the flow off the Atlantic will knock
down high temperatures a few degrees compared to this weekend.

Short-range models again seem to have a better handle on isolated
convection developing this afternoon, mainly over inland sections
of Miami-Dade County but likely less coverage than yesterday.
Coverage of afternoon showers/thunderstorms increases slightly in
coverage Memorial Day, focused over the interior up to near Lake
Okeechobee. On Tuesday, increasing SE wind flow will favor
interior and Gulf coast for isolated afternoon showers and
thunderstorms.

Extended period (Tuesday night through Saturday): low/mid level
high pressure will be centered over the Atlantic with a ridge
across North Florida. This will further establish a moist SE wind
pattern across South Florida as precipitable water values steadily
increase to around 2 inches by the end of the week. As a result,
showers and thunderstorms will increase in coverage through the
period, mainly favoring interior and Gulf coast areas in the
afternoon and early evenings and east coast sections during the
night and morning hours.

MARINE...
Sea/land breeze driven wind regime will continue through Monday,
then gradually become predominantly SE and increase some Monday
night and Tuesday as the high pressure area shifts to the north. A
light to moderate SE wind will persist through the remainder of
the upcoming week, with seas 2 to 4 feet.

FIRE WEATHER...
Lingering dry air and lower dewpoints in the 60s over SW Florida
will once again drop relative humidity values below critical
levels this afternoon. Therefore, a Red Flag Warning has been
issued for Glades and Hendry counties and inland sections of
Collier County from Noon to 7 PM. Elsewhere, humidity values will
remain above critical values but will have to be watched as well.
Similar conditions expected on Monday and a watch or warning may
be needed once again for SW Florida. The moderating trend in
moisture and RH will begin on Tuesday with conditions expected to
improve.

CLIMATE...
Here are forecast and record high temperatures for the four main
climate sites for today and Memorial Day:

Today Forecast/Record           Monday Forecast/Record

MIA 95/ 93 (1996) 93/ 94 (1951)
FLL 93/ 96 (1997)92/ 95 (1915)
PBI 94/ 94 (1928) 92/ 96 (2000)
APF 90/ 94 (1986) 90/ 96 (2011)

The record high for the month of May is 96 at Miami and Fort
Lauderdale, which especially at Miami could be reached.
&&

.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach  76  92  77  91 /   0  10  10  10
Fort Lauderdale  79  92  79  90 /   0  10  10  10
Miami            78  93  79  91 /   0  10  10   0
Naples           75  90  76  90 /   0  10  10  10

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Red Flag Warning until 7 PM EDT this evening for FLZ063-066-070.

AM...None.
GM...None.
&&


AVIATION...22/KS






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