Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

000 
FXUS62 KMFL 221909
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
309 PM EDT Wed Mar 22 2017

.DISCUSSION...

NEAR TERM /THROUGH 6 AM THURSDAY MORNING/... 

As of 305 PM EDT...High pressure continues to weaken across the 
region as a frontal boundary approaches from the north, currently 
making its way into northern Florida as of the mid-afternoon 
hours. Ahead of the front, another pleasant spring day continues 
with mostly clear skies and temperatures reaching into the 80s. 
For the remainder of today and into tonight, fair weather is 
expected to continue, with increasing cloud cover tonight from 
north to south along with increasing low-level moisture. This 
increasing low-level moisture will lead to another night of patchy
to areas of fog across portions of the interior and Gulf Coast, 
especially in vicinity of any ongoing wildfires. Low temperatures 
will range from near 60 in the interior and Gulf Coast to low and 
mid 60s along the east coast.

SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...

The aforementioned frontal boundary will continue to weaken and 
eventually wash out as it moves into South Florida Thursday into 
early Friday. Despite the decaying frontal boundary, enough low-
level moisture will be pooled out ahead of it, along with weak 
overrunning/isentropic lift, to help promote scattered showers 
across much of the region, especially for the latter half of 
Thursday. Model guidance does hint at some mid-level instability as 
well, so have added a slight chance of thunder mainly across 
portions of the lake region and Palm Beach County. Overall rainfall 
amounts are expected to generally be light, but a few areas could 
see a nice soaking rainfall of around a half an inch, helping the 
ongoing drought situation.

Behind the front, northeasterly winds will become brisk to 
occasionally breezy at times, especially along the east coast where 
wind gusts of 20-30 mph will be common at times late Thursday and 
continuing into the day Friday. Lingering showers along the east 
coast will also continue on Friday, again light in nature. 

High temperatures on Thursday will range from the upper 70s in 
northeast areas to low and mid 80s in southwest areas, warmest where 
significant cloud cover holds off the longest. Highs on Friday 
behind the front will be slightly cooler, ranging from the mid 70s 
to around 80. Low temperatures Thursday and Friday night will 
generally be in the 60s, with a few upper 50s readings in the 
interior. 

LONG TERM /SATURDAY THROUGH TUESDAY/...

The long term period will be characterized by upper-level ridging 
aloft and brisk easterly flow as the region remains under a tight 
pressure gradient from strong surface high pressure in the western 
Atlantic basin. With this synoptic pattern in place, generally fair 
weather will prevail, although with the flow off the Atlantic, 
enough low-level moisture will be in place to allow for a periodic 
isolated shower and increased clouds mainly along the east coast.

Temperatures will be near to slightly above normal for the long term 
period. 

&&

.MARINE...
Small Craft Advisory conditions possible across portions of the 
local waters as early as late Thursday...

Generally good boating conditions will continue into early Thursday 
with seas 4 feet or less and north/northeast winds under 15 knots. 
Beginning late Thursday, marine conditions will rapidly deteoriate 
as a weak frontal boundary moves across the region with scattered 
showers. In the wake of the frontal boundary, hazardous marine 
conditions for small craft are likely with increasing northeast flow 
and seas 7 feet or greater, especially for the Atlantic waters. 
Hazardous marine conditions will also be possible for the Gulf 
waters, Lake Okeechobee, and Biscayne Bay as well.

Hazardous marine conditions, especially for the Atlantic waters, are 
expected to continue through much of the weekend.

&&

.BEACH FORECAST...
A Moderate Risk of rip currents will continue for the Atlantic 
beaches through most of Thursday, with the main contributor being 
some northeasterly swell 2 feet or less. The threat for rip currents 
for the Atlantic beaches looks to increase to a High Risk beginning 
late Thursday and continuing into the weekend with increasing 
onshore flow in the wake of a frontal passage.

&&

.FIRE WEATHER...
Relative humidity values may reach critical levels across portions 
of South Florida through the remainder of this afternoon. Despite 
these values, sustained 20ft winds are expected to remain under 15 
mph with only fair dispersion. However, conditions will continue to 
be closely monitored for a heightened fire weather risk into the 
evening hours as ERC values are forecast to be in the low 30s across 
much of South Florida. 

Fire weather concerns will diminish Thursday as an approaching 
frontal boundary brings scattered showers to much of the region, and 
continue to remain diminished into the weekend with relative 
humidity values being above critical levels.

&&

.AVIATION...
For the short term, for Atlantic coast terminals weak westerly to
variable winds expected to transition to an easterly sea breeze 
around 19-20z. For all terminals mainly VFR conditions expected 
through the afternoon and evening hours. Patchy fog could develop 
interior peninsula early Thursday morning but thus far not 
expected to impact South Florida terminals, although terminal KAPF
could experience brief periods of fog around 09-12z Thursday but
low confidence.

&&

.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach  65  77  67  77 /  30  60  30  20 
Fort Lauderdale  66  79  68  77 /  10  50  40  30 
Miami            65  80  67  78 /  10  50  40  30 
Naples           64  80  61  80 /   0  30  10   0 

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
GM...None.
&&

National Weather Service Glossary of Abbreviations