Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 142358

Area Forecast Discussion
National Weather Service Miami FL
658 PM EST Wed Nov 14 2018

Showers affected APF earlier this evening, but radar data shows
the bulk of that activity has moved well north of the terminal.
VFR should continue through most of the evening at all terminals,
although a passing shower bringing brief MVFR CIGS can not be
discarded. Around 06-07Z a passing frontal boundary will begin
bringing periods of MVFR or even brief IFR cigs/vis under heavy
showers, and possibly a few thunderstorms. The main impacts of the
front will likely reach APF around 11-12Z, and the Atlantic
terminals by 13-14Z. VFR, outside of any passing shower, should
then prevail Thursday late afternoon.


.PREV DISCUSSION... /issued 404 PM EST Wed Nov 14 2018/

Latest surface analysis shows cold front across north central
florida at this time. This is not a classic front and as such it is
hard to discern it based on looking at the wind fields or even
pressure fields. Although based on the latter there is a bit of a
pre frontal trough across the Lake region. But the leading edge
of a distinctive airmass remains to the north across north
central Florida. Although integrated water vapor or precipitable
water shows values running 20-30 above normal, low and mid levels
water vapor channels show fairly dry conditions associated with
low to mid level ridge still in control across the region. This is
reflected in 12Z sounding this morning with a low to mid level
cap based around 650-600mb. Overall, very limited convective
activity outside a few widely scattered showers earlier today
across the Atlantic waters. That said, consensus of the short term
hi res guidance continues to show showers developing across
interior west and west coast next few hours and this is reflected
in the forecast.

SHORT TERM...Tonight Through Friday Night
Consensus of model guidance moves the front or leading edge of
drier/cooler airmass during the morning hours on Thursday across
western sections of South Florida and by early/mid afternoon
through the east coast. Cross sectional analysis of the front
shows not much in terms of the kinematics and associated forcing
with upper level forcing remaining well north of the region as
well. Ensemble based model anomaly fields do not show any notable
departures from normal in the height, dynamic, and thermodynamic
fields associated with this front either. Therefore, the
consensus of the guidance looks about right pointing to a chance
of showers ahead of the front this afternoon through tomorrow
morning across interior and west coast with a chance along east
coast lingering through tomorrow afternoon and across the Atlantic
waters through Thursday night. There is a slight chance of a
thunderstorm with any activity developing this afternoon/evening
across the interior and may be tomorrow just ahead of the front.
Outside of general thunder, no concerns at this time for strong
storms. Clouds will be gradual to clear behind the front in
lingering moisture band through Friday with scattered clouds
remaining along portions of the east coast and southern portions
of South Florida through the rest of the period behind the front.

Main change with this front will be a much drier and cooler airmass.
Day time highs will be around normal tomorrow (particularly along
east coast) and below normal by as much as 4 to 8 deg or so on
Friday across all of South Florida. Morning lows will also see a
substantial change next couple of days. In fact, relative to
tonight, morning lows on Friday will drop by as much as 10 to 15
deg along east coast and as much as 15 to 20 deg across the NW
interior in areas west of Lake Okeechobee and towards Naples.
Overall the morning lows friday and saturday morning will be
dropping to below normal by around 5 degrees or less Friday
morning and a bit less than that along east coast saturday
morning. The magnitude of the change and the actual temps that are
expected is a reflection of how warm morning lows have been
running as of late.

EXTENDED FORECAST...Saturday through Wednesday
High pressure ridge will be building north of the region through the
weekend with morning lows bouncing back up to near normal by
Sunday morning and a tad above normal, yet really pleasant,
through early next week. Day time highs will warm up as well
through the period but only slightly expected to remain near
normal or even may be slightly below. It will remain dry through
most of the weekend but by late in the weekend and into early next
week a slight chance to a chance of showers is forecast along
Atlantic waters and adjacent east coast as low level flow turns
out of the northeast and east with low level limited moisture
gradually on the increase.

Small craft advisory conditions are possible tomorrow ahead of the
front along the offshore gulf waters with small craft exercise
caution conditions across much of the gulf and atlantic waters
through at least first half of Friday behind the front before
conditions begin to improve into the weekend.

There will be a moderate to high risk of rip currents along the
gulf coast beaches on thursday ahead of the front with the risk
increasing to moderate or even high along east coast by Friday
and remaining elevated through the much of the weekend.

West Palm Beach  74  83  59  74 /  40  50  10   0
Fort Lauderdale  76  84  62  74 /  40  40  20   0
Miami            75  84  62  75 /  40  50  20   0
Naples           72  79  56  72 /  50  40   0   0



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