National Weather Service Raw Text Product

677 
FXUS62 KMFL 121357
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
957 AM EDT Wed Apr 12 2023

...New UPDATE...

.UPDATE...
Issued at 941 AM EDT Wed Apr 12 2023

Surface observations and GOES-16 imagery indicate that the warm 
front boundary draped across the Florida Keys is beginning to gradually
lift northward over the last several hours. To the north of the
warm front boundary across our area, isentropic ascent has
resulted in light to moderate shower activity developing and 
"filling in" across the majority of South Florida. The current 
rainfall in addition to the impressive rainfall totals over the 
last several days across portions of Miami-Dade and Broward 
counties have result in saturated soils and primed antecedent 
conditions. Flash Flood Guidance (FFG) demonstrates this well as 
the 1 hourly FFG rainfall rates are about 1.5 to 2 inches across
Miami-Dade County. With the eventual propagation of heavier
convection across these same areas over the next several hours,
the flood threat will gradually increase over the next several
hours and remain through the afternoon hours.

On the convective side of the house, the 12z MFL upper air sounding
from earlier this morning indicates some gradual turning with
height. Given the addition of enhanced vorticity along the warm 
front boundary, waterspouts could be possible offshore where 
instability is more conducive. If strong convection is able to 
develop overland, elevated winds in the 970-925mb layer could mix 
down and result in gusty winds at the surface. The main concern
today will remain the flooding risk, with the potential of flash
flooding if heavy rainfall persists for a long duration. 

No major forecast changes to discuss at this time. 


&&

.SHORT TERM...
(Today through Thursday)
Issued at 247 AM EDT Wed Apr 12 2023

An unsettled pattern will continue across South FL today into 
Thursday. An upper level low will sit over the northern Gulf today 
before crawling northward into the deep south states on Thursday. At 
the surface, there is a weak area of low pressure north of western 
Cuba, and another area of low pressure over the east-central Gulf. 
This low will become the more organized system over the next 24 
hours before lifting north towards the northern Gulf coast late 
tonight into early Thursday. A nearly stationary boundary to our 
south will start slowly lifting north today as a warm front as the 
low in the Gulf gets organized, but likely won't actually reach 
South FL until late tonight or early Thursday. Ahead of the warm 
front, deep moisture will continue to lift north into the area, with 
PWAT values over 1.6 inches in most of South FL and 1.8 inches in SE 
FL around the east coast metro. This is where the focus of the 
heaviest rain is expected today. Latest HREF guidance shows a wide 
area of 2-5 inch mean totals from the Homestead area up through 
Miami and into the Broward metro. With some instability available,
expect scattered thunderstorms to be very efficient rain-makers 
with high rates, so would not be surprised to see several 
locations receive over 6 inches today. With this kind of rainfall
over already saturated ground, this will present a problem for 
all of the typical poor drainage locations of the east coast 
metro. The Flood Watch over portions of Miami-Dade and Broward 
will remain in place through 8 PM this evening. While the rain 
will take most of the focus today, gradient easterly winds will 
remain breezy through this evening, and any stronger thunderstorms
may contain wind gusts that approach severe limits. 

The deeper moisture lifts north of the area tonight, and hi-res 
models are in fairly good agreement for a break in the rainfall 
overnight into early Thursday morning, but will keep chance showers 
and isolated thunderstorms in along the east coast. Deeper moisture 
returns across South FL during the day on Thursday as the warm front 
finally starts to lift north across the area, which will result in 
more scattered showers and thunderstorms, this time with the highest 
PoPs around the lake region and the northern east coast metro. Will 
again have to watch for some flooding issues if heavy rain falls 
repeatedly over the same areas. 

Rain and cloud cover today will hold high temps into the mid to 
upper 70s for most, but lower 80s along the Gulf coast where the 
least amount of rain is expected. Low tonight will be in the 60s 
inland to lower 70s across the east coast metro. Went a bit lower 
than guidance for high temps on Thursday, but should still reach the 
low to mid 80s over most of the area.

&&

.LONG TERM...
(Thursday night through Tuesday)
Issued at 247 AM EDT Wed Apr 12 2023

The aforementioned low pressure system and associated cut-off low 
will continue their track northeastward on Friday, skirting along
the edges of an upper level trough moving across the Midwest US. 
The surface low will continue to drag the previously stalled 
boundary northward, taking much of the moisture-rich air along 
with it. Nevertheless, sufficient moisture will remain for another
afternoon of scattered showers to materialize, over northern 
portions of the CWA, around lake Okeechobee and across local 
Atlantic waters. 

The drying trend will continue on Saturday as dry air aloft filters 
into the area, which should lead to fair weather to start the 
weekend and give us a break from the relentless rain. Unfortunately, 
dry air will not last as another frontal boundary could approach the 
area by late Sunday which will draw more Gulf moisture across the 
area to end the weekend into early next week which should be our 
next shot at scattered to numerous convection across eastern metro 
areas Sunday and Monday afternoon. Given this is at the tail end of 
the long term period, take it with a grain of salt for now as timing 
can change depending on the evolution of the synoptic features to 
our north. 

Temperatures will continue to gradually warm into the weekend, with 
high temperatures across interior South Florida possibly reaching 
the upper 80s  on Friday, then the lower 90s on Saturday and Sunday. 
Along the East Coast, temperatures will remain in the mid 80s 
through the weekend. With another frontal boundary approaching at 
the start of next week, temperatures could once again cool down 
across much of South Florida.  

&&

.AVIATION...
(12Z TAFS)
Issued at 729 AM EDT Wed Apr 12 2023

MVFR ceilings will be prevalent across our area today as a warm 
front slowly lifts north across South Florida. Numerous showers 
and scattered thunderstorms are expected today, peaking from mid 
morning through the afternoon hours. Brief IFR/LIFR conditions are
possible during times of heavy rain. East to southeast winds 
remaining breezy through this evening.

&&

.MARINE...
Issued at 247 AM EDT Wed Apr 12 2023

East to southeast winds 20-25 kts early today subside to 15-20 kts
by this evening, except for the northern Atlantic waters where
elevated winds will continue into late tonight. Atlantic seas
around 10 feet early today subside to 4-7 feet by this evening.
Gulf seas 4-7 feet this morning subside to 2-4 feet this evening.
SCA was extended through 18Z today for Lake Okeechobee, Biscayne
Bay and the Gulf waters. The SCA for the Atlantic waters runs
through 00Z this evening for the southern waters and 09Z for the
northern waters.

&&

.BEACHES...
Issued at 247 AM EDT Wed Apr 12 2023

Strong easterly flow and northeast swell will result in a
continued high risk of rips for the Atlantic beaches today. Even
though the easterly flow weakens and becomes more southeasterly on
Thursday, a lingering swell will still result in a high risk of
rips through Thursday evening. 

In addition, large breaking waves in excess of 7 feet in the surf
zone will continue through early this afternoon, so a high surf 
advisory remains until 2 PM. 

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            77  72  83  72 / 100  50  60  30 
West Kendall     79  68  86  69 / 100  40  50  30 
Opa-Locka        79  70  85  70 / 100  50  60  40 
Homestead        79  70  85  70 /  90  40  40  30 
Fort Lauderdale  77  71  82  71 / 100  60  60  40 
N Ft Lauderdale  77  71  82  71 / 100  60  70  40 
Pembroke Pines   78  70  85  70 / 100  50  60  40 
West Palm Beach  77  70  82  70 /  90  60  70  50 
Boca Raton       77  70  82  70 / 100  60  70  50 
Naples           82  70  85  72 /  90  50  40  30 

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Flood Watch until 8 PM EDT this evening for FLZ072-074-172-173.

     High Rip Current Risk through Thursday evening for FLZ168-172-
     173.

     High Surf Advisory until 2 PM EDT this afternoon for FLZ168-172-
     173.

AM...Small Craft Advisory until 2 PM EDT this afternoon for AMZ610-
     630.

     Small Craft Advisory until 5 AM EDT Thursday for AMZ650-670.

     Small Craft Advisory until 8 PM EDT this evening for AMZ651-671.

GM...Small Craft Advisory until 2 PM EDT this afternoon for GMZ656-
     657-676.

&&

$$

SHORT TERM...CMF
LONG TERM....ATV
AVIATION...Hadi