870
FXUS62 KMFL 132002
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
402 PM EDT Thu Jun 13 2024

...New LONG TERM...

.SHORT TERM...
(Rest of today through Friday)
Issued at 135 PM EDT Thu Jun 13 2024

Conditions will continue to deteriorate this afternoon as a
frontal boundary continues to sag southward towards our area.This
boundary is moving into an area of significantly enhanced
moisture (PWATs of 2.19 as of the 12Z MFL sounding), which has
resulted in the development of a robust line of showers and storms
on a NE-SW axis currently draped along the Lake region. This line
has already produced 1-2 inches of rain over the past couple of
hours; additional accumulations in the 4-8 inch range, with
locally higher amounts of 10+ inches could be possible across much
of South Florida as the line drifts southward.

A few things to note with this:
1) Even rainfall accumulations on the lower end of this range
could be dangerous for areas that have already received 10+ inches
of rain over the past couple of days. Flash flooding will be
extremely likely, and ongoing flooding in areas were standing
water was unable to drain overnight could be further exacerbated
during this event.

2) Models were originally hinting at a faster progression for
this line, but the line has been much slower in its approach over
the region. This slower pace could mean that heavy rainfall sits
over vulnerable areas for longer periods of time, leading to
rainfall acumulations that are higher than our worst reasonable
scenario.

3) Warm temperatures along the column will mean extremely
efficient warm rain processes, which could further enhance
accumulations through the afternoon hours.

To that effect, WPC has placed the whole I-75 corridor, including
Fort Lauderdale and as far south as Tamiami Trail, under a HIGH
RISK for excessive rainfall this afternoon. This means that there
is at least a 70% chance that areas 25 miles away from any given
spot could see flash flooding concerns. Additionally, there is a
very marginal concern for funnel clouds or even weak tornadoes as
this line progresses across the CWA. This risk will decrease as
the line moves southward.

Heading into Friday, a mid level shortwave trough currently over
the Gulf States will push further south into the Gulf of Mexico
as well as South Florida. At the surface, the developing area of
low pressure will push further to the northeast off of the
Carolina coastline. At the same time, deep tropical moisture will
continue to be funneled into South Florida along the south to
southwesterly wind flow. Enough instability given the synoptic
scale environment alongside the enhanced moisture plume will
produce additional rounds of precipitation during the day on
Friday. However, with the low departing from the area and the
boundary pushing southward, convective coverage will be lower than
what we`ve seen over the past couple of days, with scattered
showers and thunderstorms being the more likely outcome for precip
across the region. In general, additional rainfall amount of 2 to
4 inches will possible across most areas through Friday evening.
 Because of this, the Flood watch will remain in place across all
of South Florida through Friday Evening. High temperatures will
continue to be held down in the mid 80s across most areas on
Thursday and Friday due to the increased cloud cover and rainfall
across the region.

&&

.LONG TERM...
(Friday night through next Wednesday)
Issued at 313 PM EDT Thu Jun 13 2024

This weekend: An upper level trough will still be the dominant
synoptic feature over the area and it will come into phase with an
amplifying trough over the eastern United States and Canada. As
the surface low off the Southeast United States moves to the
northeast, surface flow across South Florida will become easterly
by Sunday afternoon which will be the start of a return to
normalcy. Modeled PWATs will still remain at or above 2 inches
Saturday and Sunday, which is at or above the 90th percentile for
this time of year. It is possible we remain in the `moisture tail`
of the surface low through the weekend, with the most enhanced
moisture draped across far southern portions of the area. Showers
and storms are likely each day through the weekend before drier
air finally begins to filter across the area on Monday. As the low
continues to push further and further away from South Florida,
the coverage of showers and storms is not expected to be as
widespread or numerous as what we experienced earlier this week.
Still, given the extremely wet conditions this week, the Flood
Watch may need to be extended into the weekend.

Early next week: Surface high pressure will build across the region
again late Sunday into Monday which should return us to a more
typical summertime easterly regime. This will allow the eastern
sea breeze to progress relatively far inland and keep the best
chances for showers and storms across interior South Florida and
Southwest Florida each afternoon.

Highs through the period will be in the upper 80s with heat indices
in the upper 90s to lower 100s. With the return of the easterly
regime, Southwest Florida will experience slightly warmer
temperatures and heat indices each day.

&&

.AVIATION...
(18Z TAFS)
Issued at 135 PM EDT Thu Jun 13 2024

MVFR/IFR conditions will be possible for all terminals this
afternoon as a large band of SHRA/TSRA pushes through. Best timing
for most terminals will be between 18-22Z with TEMPOs currently
in place. Short-fuse amendment will likely be needed as the line
approaches and moves through. Generally southerly to southwesterly
winds will prevail outside of any storms and storm outflows.
Conditions improve overnight, but scattered showers and
thunderstorms will once again be likely on Friday.

&&

.MARINE...
Issued at 135 PM EDT Thu Jun 13 2024

A moderate to fresh south to southwesterly wind flow will remain in
place across the local waters through the end of the week. Seas
across the Atlantic and Gulf waters will remain at 2 feet or less
through Friday. Winds and seas could be locally higher in and around
any shower or thunderstorm activity.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            76  87  77  88 /  80  80  70  70
West Kendall     73  87  74  89 /  80  80  70  70
Opa-Locka        75  87  77  89 /  80  80  70  70
Homestead        75  86  75  88 /  90  80  70  70
Fort Lauderdale  76  86  77  87 /  80  70  70  70
N Ft Lauderdale  76  87  77  88 /  80  70  70  70
Pembroke Pines   76  88  77  90 /  80  80  70  70
West Palm Beach  74  87  74  88 /  70  70  60  70
Boca Raton       75  87  75  88 /  70  70  70  70
Naples           77  87  77  89 /  70  80  70  70

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Flood Watch through Friday evening for FLZ063-066>075-168-
     172>174.

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

$$

SHORT TERM...ATV
LONG TERM....RAG
AVIATION...ATV