Lightning Strike in Florida, July 30, 2019

Area Forecast Discussion
National Weather Service Miami FL
129 PM EDT Tue Jul 30 2019

.AVIATION...
Afternoon convection has been slow to start. Howveer, models are
still showing TSRA after around 20z, mainly in the interior. With
the uncertainty as to the location, it still may be close enough
to affect the terminals, so have kept VCTS at all sites this
afternoon. Also, outflow boundaries could cause TS initiation
closer to any o fthe sites, even if the main area is well away
form the coastlines. Otherwise, VFR conditions across S Florida.

&&

.PREV DISCUSSION... /issued 1026 AM EDT Tue Jul 30 2019/

UPDATE...
Today could be an interesting day. This mornings sounding showing
plenty of PWAT, at 1.9 inches. CAPE is lower than it has been for
the last few days. However, this is likely due to the convection
that has been occurring to the east. The 500mb temps are somewhat
warmer, at around -7C. In modifying the sounding, this afternoons
CAPE should be over 3000 Joules, and the NCAPE around .28. DCAPE
came in at just over 1100 J/Kg on the modified sounding. This
could lead to some strong storms this afternoon. Also, with the
convection keeping the east coast cooler this morning, and plenty
of sunshine in the interior, a stronger baroclinic zone may be
able to form, casing a stronger sea breeze from the Atlantic coast
this afternoon. One hindering factor is the lack of shear. Unless
the shear picks up in the mid levels, the storms may be
vertically stacked, which would keep them from becoming too
strong s the updraft would be cutoff by the downdraft. However,
this could be changed if the lower level flow becomes strong, due
to the stronger sea breeze. Even so, the steering flow is weak,
which could allow for heavy rain to occur for extended amounts of
time, or through training/backbuilding over the area. This could
lead to the typical ponding of water on roadways, mainly in the
western Atlantic metro areas. The other concern would be outflow
boundaries that cause development back to the east, over the metro
areas, which become stationary. But this would be more of a
concern mid afternoon into the evening hours. Overall, the best
chances today will be over the central interior of the CWA, and
the forecast is reflecting that. Still can not rule out some
strongstorms affecting any portion of South Florida through the
afternoon hours.

PREV DISCUSSION... /issued 328 AM EDT Tue Jul 30 2019/

DISCUSSION...

Today and Tonight...

Mid-level ridging will remain prominent from the western Atlantic
into the eastern Gulf of Mexico, as upstream troughing migrates
through the Ohio and Tennessee Valleys. This will generally maintain
surface high pressure through most of the region, with the exception
of weak troughing now located to our east. This trough should help
to increase the early morning shower and thunderstorm coverage over
the Atlantic waters a bit, with some of this potentially spilling
into the east coast metro areas through late morning as the sea
breeze progresses inland. Thereafter, given the light southeast
wind regime, the greater shower and thunderstorm coverage should
shift towards inland southwest Florida into the Lake region as the
sea breezes collide. Given cool temperatures aloft and robust
surface heating lapse rates should be decently steep during the
afternoon (mid level values approaching to potentially exceeding
6.5 degrees Celsius per kilometer). Given this, would expect any
taller thunderstorm cores to maintain an attendant risk of strong
to locally damaging downburst winds along with localized flooding
and of course frequent lightning. Those with outdoor plans should
remain weather aware and have a way to receive weather
information. Temperatures will be seasonal with highs mostly in
the lower 90s (cooler near the coasts) and lows in the 70s to
around 80.

Wednesday through Thursday...

Deep layer ridging will dominate through the period with a light
easterly low-level wind regime. This will again focus shower and
thunderstorm development along the sea breeze boundaries, with the
greatest afternoon and evening coverage over inland southwest
Florida. Deeper moisture should start encroaching from the southeast
towards the end of this period. Temperatures should be seasonal.

Friday through Monday...

The mid-level ridge will retreat to our east as troughing digs from
the Southeast CONUS into the northern Gulf of Mexico. Deeper
tropospheric moisture will be drawn poleward across our ahead of
the trough in association with an area of low pressure approaching
from the southeast. This should result in more numerous coverage
of showers and thunderstorms across our area from Friday into
early next week. The National Hurricane Center is monitoring this
low pressure area for a low chance (10% over the next 5 days) of
tropical development. Regardless of any development (or lack
thereof), periods of heavy rainfall could lead to localized
flooding concerns during this period so keep up with this evolving
forecast.

MARINE...

East to southeast winds are expected over the next few days with
generally benign boating conditions outside of thunderstorms. For
late week into the weekend expect deteriorating conditions as low
pressure moves through the region. Winds should increase into the 10-
15 knot range along with more widespread shower and thunderstorm
coverage into early next week.
&&

.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach  79  88  78  90 /  20  30  20  40
Fort Lauderdale  81  87  79  88 /  20  30  20  40
Miami            80  88  79  90 /  30  30  20  50
Naples           78  89  74  90 /  20  70  30  60

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
GM...None.
&&

UPDATE...13
DISCUSSION...34/SPM
MARINE...34/SPM
AVIATION...13

Hazardous Weather Outlook for South Florida
National Weather Service Miami FL
416 AM EDT Tue Jul 30 2019

AMZ610-630-650-651-670-671-FLZ063-066>075-168-172>174-GMZ656-657-676-
302030-
Lake Okeechobee-Biscayne Bay-
Coastal waters from Jupiter Inlet to Deerfield Beach FL out 20 NM-
Coastal waters from Deerfield Beach to Ocean Reef FL out 20 NM-
Waters from Jupiter Inlet to Deerfield Beach FL from 20 to 60 NM-
Waters from Deerfield Beach to Ocean Reef FL from 20 to 60 NM
excluding the territorial waters of Bahamas-Glades-Hendry-
Inland Palm Beach-Metro Palm Beach-Coastal Collier-Inland Collier-
Inland Broward-Metro Broward-Inland Miami-Dade-Metro Miami-Dade-
Mainland Monroe-Coastal Palm Beach-Coastal Broward-Coastal Miami-
Dade-Far South Miami-Dade-
Coastal waters from Chokoloskee to Bonita Beach FL out 20 NM-
Coastal waters from East Cape Sable to Chokoloskee FL out 20 NM-
Waters from Chokoloskee to Bonita Beach FL from 20 to 60 NM-
416 AM EDT Tue Jul 30 2019

...Scattered to numerous thunderstorms expected today...
...Isolated Waterspouts possible over the Atlantic waters...

This hazardous weather outlook is for South Florida.

.DAY ONE...TODAY AND TONIGHT

Thunderstorms: Storm coverage is expected to be scattered to
numerous this afternoon, mainly across the interior and areas west of
Lake Okeechobee. Elsewhere, activity is forecast to be more isolated
to scattered. Best chances will be mid- afternoon through early
evening with some storms possibly lingering into the overnight hours
across portions of the local waters. The primary concerns will be
gusty winds, heavy rainfall and frequent cloud to ground lightning.

Wind: Stronger thunderstorms could produce wind gusts in excess of
45 to 55 mph.

Waterspouts: There is a potential for isolated waterspouts over the
South Florida Atlantic waters today and tonight.

Temperatures: Heat indices are forecast to reach around 105-107
degrees this afternoon, mainly for the interior and west coast, along
with portions of eastern Palm Beach County.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

Scattered to locally numerous thunderstorms are expected each day
through the period with best chances across the interior and Lake
region. Frequent lightning, locally heavy rainfall, and gusty winds
will be the primary hazards with these storms.

.SPOTTER INFORMATION STATEMENT...

Widespread spotter activation is not anticipated, however individual
spotters are encouraged to report high wind, hail and flooding to
the National Weather Service forecast office in Miami.

For more information...visit the National Weather Service in
Miami website at www.weather.gov/miami.