Scientific Forecaster Discussion
fxus62 kmfl 152001
Area forecast discussion
National Weather Service Miami Florida
301 PM EST sun Dec 15 2019
Short term (tonight through monday)...
High pressure at the surface and zonal flow aloft will lead to a
benign weather pattern across southern Florida through Monday. As
the high builds in strength and slides eastward into the Atlantic,
easterly flow will continue over the region through Monday. As the
gradient increases, Monday could be much more blustery compared to
today with wind gusts of 20 to 25 mph possible, particularly along
the Atlantic coast.
Temperatures will be a few degrees warmer tonight with much of
southwest Florida in the upper 50s to 60s while Southeast Florida
ranges from the 60s to around 70. Areas right along each coast will
be warmer thanks to the moderating influence of the waters. Most of
the area will rebound into the 80s on Monday afternoon, but the
gusty winds may make things feel a few degrees cooler. With the
easterly to southeasterly flow persisting, moisture return and
moderating temperatures will continue into Monday night with
temperatures ranging from the mid 60s over inland southwest Florida
into the mid 70s along the Atlantic coast.
Monday night through Wednesday night...
Large-scale troughing will advance across the eastern states as a
closed upper circulation progresses through the upper Great Lakes
region. Surface low pressure will deepen northeastward from the
southern Appalachians towards the Canadian Maritimes as an
associated cold front crosses the southern Florida Peninsula on Tuesday
night to Wednesday morning. Moisture will increase in the lowest
20 kft of the troposphere in association with the low-level front
and some weak vorticity perturbations aloft as modest instability
builds across the area on Tuesday afternoon. This will lead to
increasing shower chances, along with a few thunderstorms possible
during the daylight hours on Tuesday. Showers remain possible
into Wednesday in the cool Post-frontal regime until the
lingering moisture exits. 850 mb moisture convergence is noted on
Tuesday afternoon into Tuesday evening, although corfidi vectors
appear to remain progressive. While this synoptic setup doesn't
appear overly favorable for a widespread heavy rain event, we'll
need to keep an eye on the mesoscale details in case a localized
heavy rain risk develops over some portion of our area. High
temperatures should be mild on Tuesday given southerly flow
advecting in a warm/humid airmass, with cooling expected by
Wednesday with a cool, cloudy, and showery Post-frontal regime.
Much cooler readings are expected by Wednesday night with lows
dropping into the 40s west of the lake, 50s for the West Coast and
most inland areas, and lower 60s for the East Coast.
Thursday through Sunday...
A sharpening upper trough will progress through the eastern states
with a consensus of the forecast models coming into better agreement
in carving out a closed low over the Gulf Coast states on Saturday,
before tracking it east to east-southeast across Florida on Sunday.
This pattern increases the chances for surface cyclogenesis
somewhere in the vicinity of central/South Florida over the
weekend, along with the possibility for impactful weather
including heavy rainfall and strong thunderstorms. While things
may change given that we're several days out, this portion of the
extended forecast will require careful attention in the days going
forward. Temperatures should be near to perhaps above average
depending the ultimate location of any surface low development and
whether our area makes it into a solid warm sector.
High pressure builds in to kick off the work week, with persistent
easterly to southeasterly flow remaining and the potential for
elevated seas and periods of easterly wind surges. A mid-week cold
front could bring the return of hazardous conditions over the area
waters to close out the work week.
Aviation (18z tafs)...
Generally VFR through the period with easterly flow becoming gusty
on Monday. Cloud cover from the Atlantic is possible near the end
of the forecast period.
Along the Atlantic beaches, the rip current risk should diminish as
the weekend concludes. By early in the week, the easterly to
southeasterly wind flow picks up and so will the elevated rip
current risk. Another cold front will push across the region mid-
week which will cause hazardous marine conditions to develop leading
to the return of an elevated rip current threat to close out the
Preliminary point temps/pops...
West Palm Beach 68 81 71 82 / 10 20 30 40
Fort Lauderdale 71 81 73 81 / 10 20 20 30
Miami 70 83 73 83 / 10 20 20 30
Naples 63 84 68 82 / 0 0 10 50