Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

000 
FXUS62 KMFL 291201
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
801 AM EDT Wed Mar 29 2017

.AVIATION...
There will be light winds this morning with VFR conds. Aft
29/1600Z, SE winds around 10 KT 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 MSL. Otherwise, generally clear. Along the Gulf Coast, a 
SW sea breeze will develop early this afternoon and diminish by 
evening.

&&

.PREV 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 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 TN/OH 
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 FL 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 TN/OH 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 RH 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 RH 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...
FL...Red Flag Warning from 1 PM this afternoon to 7 PM EDT this 
     evening for FLZ070.

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

National Weather Service Glossary of Abbreviations