Scientific Forecaster Discussion
fxus62 kmfl 122027
Area forecast discussion
National Weather Service Miami Florida
327 PM EST Thu Dec 12 2019
Tonight through Saturday night...
A frontal boundary stalled around the Lake Okeechobee region will
begin to retreat back northward overnight. Bountiful amounts of
moisture remain over the region, allowing for showers to develop
and focus over portions of the area including along the East Coast
Metro and potentially the Gulf Coast Metro areas this afternoon
and evening. Cannot rule out a thunderstorm or two, particularly
in areas around the frontal boundary. The focus for most of the
convection will remain from the Interstate 75/Alligator
alley/Interstate 595 corridor northward, though overnight into
Friday morning the focus will shift back towards the Atlantic
Aloft, a mid-level shortwave trough running ahead of the main
trough axis will push across the region tonight into Friday
morning which could spur that additional convection referenced in
the previous paragraph. Once that has pushed east, the main trough
axis begins to advance eastward. Accordingly, the surface frontal
boundary will push across the eastern Gulf of Mexico towards the
peninsula of Florida on Friday night into Saturday. As the sun
rises on Saturday morning, the surface front will be knocking on
the door of southern Florida.
With the surface low somewhere along the southern Atlantic coast
early Saturday morning and then quickly pushing towards the mid-
Atlantic states, the location of the low and trailing frontal
boundary will be important to monitor. If the frontal boundary is
able to clear across the peninsula into the Atlantic, drier and
cooler air behind it will allow for the weekend to dry out faster.
If the boundary stalls or lingers across or close to the
peninsula, some portions of Southeast Florida could see some
chances of rain. The forecast will feature a slight chance of
showers for Saturday afternoon to acknowledge this potential for
the forecast to change.
By Saturday night/early Sunday morning, things should begin to
dry out and temperatures will begin to decrease. Mid to upper 50s
will sneak into the Lake Okeechobee region while upper 50s to
around 60 will reach into much of southwest Florida. The majority
of Southeast Florida will remain in the 60s.
Sunday through Monday...
Drier and slightly cooler conditions will continue across the
region Sunday into Monday, as high pressure quickly builds over
the southeast Continental U.S. Behind the aforementioned cold front. As the
surface anticyclone continues sliding eastward, winds will follow
suit, swinging out of the east then southeast, effectively
increasing available moisture through mid week.
Temperatures will also slowly creep back up across the area as
winds increase out of the east. Afternoon temperatures will be
near 80 along the East Coast and mid 80s across southwestern
portions. Evening temperatures will also reflect a gradual warming
trend with coldest lows Sunday night in the mid 50s across the
lake region to mid 60s along the East Coast. By Monday night, most
of the region will experience temperatures in the upper 50s to
low 60s with the East Coast in the mid to upper 60s.
Tuesday through Thursday...
The mention of rain then returns to the forecast on Tuesday,
ahead of the next cold front, which will begin it's decent down
the peninsula. While global models maintain similar timing, they
have slowed down a pinch, depicting a frontal passage on
Wednesday instead of Tuesday evening. The GFS remains the weaker
solution with the front losing it's upper level support shortly
after passage, while the European model (ecmwf) maintains a more robust, convective
boundary. Regardless, scattered showers with isolated
thunderstorms will be possible Tuesday ahead of the front through
the afternoon and early evening hours on Wednesday.
One concern prior to the front's arrival is the chance of patchy
fog early Wednesday morning across South Florida, with isolated
areas of fog possible over the interior.
Behind the boundary, the European model (ecmwf) unsurprisingly depicts stronger
cold air advection and blended guidance has dropped overnight
temperatures a degree or two from the previous forecast. However,
temperatures are still progged to dip into the upper 40s to low
50s near Lake Okeechobee and low 60s along the East Coast early
Thursday and Friday morning. Thus, given this is still close to
the end of the forecast period, and models differ substantially
with the finer details, have maintained a middle of the Road
solution and will continue to monitor as we get closer in time.
hazardous boating conditions will continue over the Atlantic
coastal waters requiring a Small Craft Advisory with the arrival
of a north swell and winds to around 20 knots. These conditions
are expected to peak tonight, then begin to subside on Friday as
the swells decrease and the winds veer to the southeast and weaken.
Generally benign weather is expected for the weekend.
a stalled front around Lake Okeechobee will keep convection
focused along and north of an fll-apf line this afternoon. Some
Atlantic showers could still sneak into mia/opf/tmb. Sub-VFR
conditions are possible with convection. Activity should decrease
later this evening into the overnight with Atlantic convection
flaring back up late overnight into the morning hours.
an increasing northerly swell will bring an elevated rip current
risk and possibly rough surf to the Atlantic beaches through
tonight. This swell will begin to subside on Friday, but an
elevated rip current risk may linger through the weekend into
early next week for many of the Atlantic beaches.
Preliminary point temps/pops...
West Palm Beach 68 81 65 82 / 40 50 30 20
Fort Lauderdale 70 81 68 82 / 40 30 30 10
Miami 70 82 68 83 / 30 30 30 10
Naples 65 80 67 80 / 30 20 30 30
Florida...high rip current risk through Friday evening for flz168-172-173.
Am...Small Craft Advisory until 4 am EST Friday for amz650-651-670-