Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus62 kmfl 291427 
afdmfl

Area forecast discussion
National Weather Service Miami Florida
1027 am EDT Wed Mar 29 2017

Update...
the 12z mfl sounding indicated shallow moisture and light winds
near the surface, consistent with the patchy fog observed over
the interior this morning, and drier air in the mid and upper
levels. High pressure over South Florida will continue to bring
mainly sunny skies and light southeast winds through this
afternoon. With an easterly flow pattern in place, maximum
temperatures should top out highest in the western interior,
where upper the 80s may reached. Made slight adjustments to the
short term winds and dewpoints to account for latest trends.
Otherwise, the forecast appeared on track.

&&

Previous discussion... /issued 801 am EDT Wed Mar 29 2017/

Aviation...
there will be light winds this morning with VFR conds. Aft
29/1600z, southeast winds around 10 knots will develop along the East Coast
with occasional higher gusts. These winds will dissipate aft
29/2300z, with the loss of diurnal heating. Expect few/sct fair
weather cumulus to form during the afternoon with bases around
3500 ft mean sea level. Otherwise, generally clear. Along the Gulf Coast, a
SW sea breeze will develop early this afternoon and diminish by
evening.

Previous discussion... /issued 404 am EDT Wed Mar 29 2017/

Discussion...

Today-thursday: surface high center will slide just to our east
today, before weakening on Thursday ahead of the next system moving
east. Weak mid-upper level ridge sliding across the peninsula the
next two days will also help keep the overall atmosphere dry and
suppressed with continuing fair weather across South Florida.

Weak pressure gradient will allow both sea breezes to push inland
both afternoons, though as low level flow becomes more southeast
Thursday the Gulf sea breeze is not expected to push as far inland
as previous days. Can't rule out a shower or two with the sea breeze
collision given the warm afternoon temperatures, but chances look to
low for a mention in the forecast as of now. Patchy overnight fog is
possible over interior sections.

Highs will be in the low to mid 80s for east and Gulf coasts, and
upper 80s to near 90 for the interior. Lows will generally be in the
60s, though some East Coast locations may linger closer to 70.

Friday-saturday: the GFS and European model (ecmwf) have come into better agreement
in the handling of the upper level low that is expected to cross
through the Central Plains today, and lift out through the Tennessee/Ohio
Valley and mid-Atlantic late week. Both models have trended weaker
with the southern stream of this system, keeping a more robust
surface low further north. The net result is a slower and weaker
front that slides into the Florida Peninsula Friday and Saturday.

The bulk of activity associated with the front itself looks to hold
off until later in the day on Friday. However, gusty southerly
flow will increase low level moisture across the region, which
along with a robust 90-100kt jet crossing the peninsula, and above
normal daytime highs in the mid 80s will help generate a few
afternoon showers and storms. While models show the bulk of
activity over the Gulf of Mexico weakening substantially as it
nears South Florida later on Friday, will have to watch for
potential of more organized convection holding together.

With the boundary slowing down, the threat for isolated showers and
a storm or two will linger into Saturday.

Early next week: models are now trending towards the frontal
boundary washing out across the region by Sunday rather than pushing
through, leaving some lingering low level moisture across the
region. However, Sunday does look to be the driest day of the
weekend with only isolated showers.

The southern stream jet remains active into next week with the next
upper level low swinging through the southern tier of the US with a
robust surface low expected to move into the Tennessee/Ohio valleys Monday-
Tuesday. Though timing differs between the models, especially this
far out, it looks like we can expect unsettled weather as increasing
south-southeast flow brings deeper moisture back into the region.

Marine...generally good boating conditions will continue with
east-southeast winds less than 10 kts today, then picking up out
of the southeast 10-15kts on Thursday. Gulf Coast breeze will be
more active this afternoon, bringing winds around to the west-
northwest, with the stronger offshore component limiting, though
completely prevent the development of the Gulf Coast breeze
Thursday.

The approach of a frontal boundary on Friday will allow winds to
increase out of the south-southeast to 15-20kts over most of the
local waters. This will briefly bring seas up to 3-4ft over both the
Gulf and Atlantic, along with bringing the threat for showers and
storms Friday and Saturday.

Winds over the weekend look light and variable as the boundary
washes out in the vicinity, before increasing again by early next
week ahead of the next low pressure system.

Fire weather...with dry air in place and little, if any
precipitation expected across the region through Thursday,
afternoon relative humidity values are expected to drop below 40% across the
interior for several hours both this afternoon and again Thursday
afternoon. For Glades, Hendry, and interior Collier counties,
several hours of relative humidity values below 35% can be expected. Although
fuels are quite dry, erc values remain below thresholds for most
areas and overall wind speeds are expected to remain less than 10
mph. However, a red flag warning will be needed in locations that
currently have lowered criteria due to enhanced fire concerns.
&&

Preliminary point temps/pops...
West Palm Beach 84 67 84 67 / 0 0 0 10
Fort Lauderdale 84 71 82 71 / 0 0 0 10
Miami 85 69 84 70 / 0 0 0 10
Naples 83 66 84 66 / 0 10 0 0

&&

Mfl watches/warnings/advisories...
Florida...red flag warning until 7 PM EDT this evening for flz070.

Am...none.
GM...none.
&&

National Weather Service Glossary of Abbreviations