Severe Thunderstorm Warning 110, NWS Melbourne, FL

Area Forecast Discussion
National Weather Service Melbourne FL
931 AM EDT Tue Jun 20 2023

...New UPDATE, AVIATION, PREV DISCUSSION...

.UPDATE...
Issued at 909 AM EDT Tue Jun 20 2023

What has started as a quiet morning across east central Florida is
about to change through the late morning and as we head into the
afternoon hours. Radar imagery shows a line of scattered to
numerous showers and lightning storms that currently sits
upstream of central Florida which are entering Lake and Volusia
counties. Analysis charts signal that the activity this morning is
driven by a major shortwave trough which is indicated by areas of
PVA across north Florida with increased upper-level diveragance.
Additionally, modest lift is apparent with a 25-30kt southwesterly
LLJ draped across northern and central Florida coupled with
20-25kts of bulk shear (0-6km).

The aforementioned ingredients, as well as plenty of instability
(1,500 J/kg + MLCAPE) and moisture (PWATs in the 1.6-2.0" range)
in place will result in a risk for strong to marginally severe
storms as we progress into the afternoon. Scattered to numerous
showers and lightning storms are expected to increase from the
northwest towards I-4 to the southeast towards the Treasure Coast
this afternoon and evening. For this reason, a Marginal Risk for
severe storms has been placed over central Florida from the Storm
Prediction Center. The primary hazards with any strong to severe
storms that develop will be damaging wind gusts up to 50-60mph,
hail up to 1", heavy rainfall (1-2" and locally up to 4"), and
frequent lightning strikes. Afternoon high temperatures are on
track to reach the upper 80s to low 90s.

&&

.AVIATION...
(12Z TAFS)
Issued at 909 AM EDT Tue Jun 20 2023

VFR conditions are expected outside of thunderstorms. Afternoon
showers and storms with VCTS introduced. Breezy west to
southwesterly winds gusting up to 22kts this afternoon, before
relaxing overnight. Rain showers linger into the early overnight
hours, then dry air filters in through the morning.

&&

.PREV DISCUSSION...
Issued at 909 AM EDT Tue Jun 20 2023

Today-Tonight...Another hot day day with multiple rounds of
showers and thunderstorms. The mid-level low starts to settle over
the Deep South where it will meander for a couple days, helping to
produce rounds of showers and thunderstorms. South to
southwesterly flow will continue to push temperatures into the
L90s along and south of the I-4 corridor, while to the north,
higher rain chances and cloud cover keep temperatures graciously
in the U80s. Winds out of the southwest become breezy across the
interior in the afternoon, and should keep the east coast sea
breeze pinned near the coast or just offshore. Overnight lows in
the low 70s.

Another early start and multiple round day of showers and
thunderstorms. An initial round of convection is forecast to reach
Lake/Volusia just before sunrise, sweeping southeastward through
the morning. May or may not see a break before diurnal convection
starts to fire in the afternoon, which looks to be very stormy
once again, with scattered to numerous showers and thunderstorms
into the late evening. Confidence in convective evolution becomes
very low at this point due to the chaotic interaction of multiple
boundaries, but pretty good signal from models the bulk of the
activity should dissipate or push offshore before midnight, but
could continue to see some isolated showers and thunderstorms
through the night, especially from Osceola and Brevard counties
northward. Once again strong to marginally severe thunderstorms
will be possible, with a lot riding on how soon this morning's
initial round of convection and cloud cover can clear out for
instability to recover. Not much energy available for the first
round, with MUCAPE values generally around 1,500 J/kg, but could
still see some gusty winds up to 45 mph. Going into the afternoon,
MUCAPE increases to 2,000-3,000 J/kg, with some guidance going as
hard as 3,500 J/kg or more. Yesterday's afternoon and evening
XMR/TBW soundings both came in with over 5,000 J/kg, supporting
the potential for higher values, especially if this morning's
first round doesn't really pan out. Model lapse rates are
unimpressive, most less than 6 C/km, but the vast majority of the
models have high cloud cover through the afternoon. Should we see
more clear skies in the morning, low level lapse rates would
become much steeper, increasing the potential for hail. Shear is
once again meager, with 0-6km 25 kts or less, but increased
convergence/shear along outflow boundaries could help overcome
this. Primary storm threats will be gusty winds up to 50 mph with
locally higher gusts to 60 mph possible in severe storms, hail up
to 1", frequent to excessive cloud to ground lightning, torrential
downpours, and a brief tornado along outflow boundary interactions
can't be ruled out. Heavy showers and storms will be able to
deliver a quick 1-2" of rainfall, with locally higher accumulation
of 4" possible, which could lead to ponding of water on roads, and
minor flooding of low lying and poor drainage areas.

Wednesday-Thursday...Mid/upper level cut-off low across the
southeast U.S. will begin to lift slowly northward, which will allow
the subtropical ridge axis south of FL to gradually build back
northward as well. This will keep a deep offshore flow in place
through this period, with plenty of moisture (PW values 1.8 to 2.0")
to generate higher coverage of showers and storms each day (rain
chances up to 70-90%). Passing disturbances aloft may lead to an
earlier start to convection, especially on Wednesday, with numerous
showers and storms developing and pushing east-northeast across the
area and offshore. Boundary or storm collisions with the east coast
sea breeze may lead to an enhancement in storm development near the
coast each afternoon, but the sea breeze looks unlikely to form
north of the Treasure Coast on Wednesday due to stronger offshore
flow. Strong to isolated severe storms will continue to be possible,
each day.

Earlier start to storms on Wednesday and greater cloud cover will
keep max temps in the upper 80s to low 90s. Then on Thursday, highs
are forecast to rise to the low to mid 90s, with heat index values
102-107 before storms coverage increases into the afternoon.
Overnight lows will continue in the low to mid 70s.

Friday-Monday...Low aloft continues to move northward as it
gradually weakens and eventually becomes absorbed into the northern
stream flow this weekend. However, a lingering trough remains in
place along the eastern U.S. seaboard and pushes off the eastern
coast late in the weekend into early next week. At the surface, the
subtropical ridge axis continues to lift northward and builds across
the area through the period, with low level offshore flow backing to
the S/SE. Models are not showing as much of a moisture surge into
the weekend as it was previously, and maintains PW values around 1.8
to 2.0". However, this will still keep rain chances above normal
from late week through early next week, with PoPs up to 70-80
percent. Low to mid level winds weaken into the weekend through
early next week, with temps aloft gradually warming. This may reduce
the overall threat for any isolated severe storms, but a few strong
storms will continue to be possible each afternoon. Additionally,
weakening steering winds may increase the risk for locally heavy
rainfall and minor flooding issues.

With flow starting to become a little more onshore, highs will range
from the upper 80s along the coast to upper 80s/low 90s over the
interior each afternoon. Lows will continue in the low to mid 70s.

&&

.MARINE...
Issued at 343 AM EDT Tue Jun 20 2023

Today-Tonight...Generally unfavorable boating conditions, becoming
poor offshore. Winds SW-S 10-15 kts, increasing to 15-20 kts
offshore in the late afternoon (Brevard waters) and overnight (all
offshore segments). Small craft should exercise caution. Seas 2-3
ft, occasionally up to 4 ft in the Gulf Stream north of the Cape,
and 1-2 ft to the south. Scattered to numerous showers and
thunderstorms pushing offshore expected through the day and night.
Some storms could become strong to marginally severe, capable of
gusty winds over 35 kts, locally higher seas, frequent to
excessive cloud to water lightning, and hail.

Wednesday-Saturday...Ridge axis south of the area will gradually
lift back northward through late week and across the area by the
weekend. S/SW winds 10-15 knots, potentially up to 15-20 knots
offshore on Wednesday, will become predominately S/SE Friday and
into the weekend. Seas will continue to range from 1-2 feet
nearshore and up to 2-3 feet offshore. Main concern will continue
to be higher coverage of offshore moving storms, especially
through mid to late week, with some strong to isolated severe
storms possible each day.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  89  73  88  72 /  70  50  90  40
MCO  91  74  89  74 /  70  60  90  40
MLB  92  74  90  74 /  60  50  80  40
VRB  93  72  91  73 /  60  40  80  40
LEE  88  73  87  73 /  70  60  90  40
SFB  90  74  89  73 /  70  50  90  40
ORL  91  74  89  74 /  70  60  90  40
FPR  92  74  90  74 /  50  40  70  40

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&

Fehling/Leahy

Hazardous Weather Outlook
National Weather Service Melbourne FL
1006 AM EDT Tue Jun 20 2023

AMZ550-552-555-570-572-575-FLZ041-044>046-053-058-141-144-154-159-
164-247-254-259-264-347-447-547-647-747-210300-
Flagler Beach to Volusia-Brevard County Line 0-20 nm-Volusia-
Brevard County Line to Sebastian Inlet 0-20 nm-
Sebastian Inlet to Jupiter Inlet 0-20 nm-Flagler Beach to Volusia-
Brevard County Line 20-60 nm-Volusia-
Brevard County Line to Sebastian Inlet 20-60 nm-
Sebastian Inlet to Jupiter Inlet 20-60 nm-Inland Volusia-
Northern Lake-Orange-Seminole-Osceola-Okeechobee-Coastal Volusia-
Southern Lake-Coastal Indian River-Coastal Saint Lucie-
Coastal Martin-Inland Northern Brevard-Inland Indian River-
Inland Saint Lucie-Inland Martin-Mainland Northern Brevard-
Northern Brevard Barrier Islands-Inland Southern Brevard-
Mainland Southern Brevard-Southern Brevard Barrier Islands-
1006 AM EDT Tue Jun 20 2023

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL FLORIDA.

.DAY ONE...TODAY AND TONIGHT.

.THUNDERSTORM IMPACT...
Scattered to numerous showers and lightning storms into the
afternoon and through the late evening. Strong to marginally
severe storms will be possible and capable of wind gusts up to 50
to 60 mph, frequent to excessive cloud to ground lightning strikes,
hail up to 1 inch, and heavy rainfall. In addition, a brief
tornado along boundary interactions can't be ruled out.

.FLOOD IMPACT...
Locally heavy rainfall will have the potential to accumulate 1 to
2 inches in a short period of time. Locally high accumulations up
to 4 inches will be possible, which will lead to ponding of water
on roads, and minor flooding of low lying and poor drainage
areas, especially where heavy rains have already fallen.

.EXCESSIVE HEAT IMPACT...
The combination of hot afternoon temperatures in the low to mid 90s
and high humidity will lead to peak Heat Indices between 101 and
106 degrees this afternoon. Persons engaged in outdoor activities
should remain well hydrated and take indoor rest breaks in an air
conditioned location, if available. NEVER leave children or pets
unattended in a car for any amount of time.

.MARINE THUNDERSTORM GUST IMPACT...
Wind gusts of 35 knots or greater will be possible over inland
lakes, the Intracoastal Waterway, and Atlantic waters, as
lightning storms move southeastward at around 15 knots. Boaters
across the Intracoastal and near shore Atlantic waters should
watch for storms approaching from the north and west, and seek
safe shelter well in advance as storms.

.WIND AND SEA IMPACT...
Southwest to south winds will increase to 15 to 20 kts across the
local Atlantic waters this afternoon. Small craft should exercise
caution.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.
Above normal rain chances will continue through the week.
Scattered to numerous lightning storms each afternoon will be
capable of producing gusty winds, small hail, frequent lightning,
and heavy rainfall. A few storms will become strong to marginally
severe.

The combination of afternoon high temperatures in the lower 90s
and humidity will produce peak heat indices up to 106 through Wednesday,
mainly in Okeechobee and the Treasure Coast counties.

.SPOTTER INFORMATION STATEMENT...
Spotters should monitor the weather and self activate if needed.

Fehling

Preliminary Local Storm Report
National Weather Service Melbourne FL
209 PM EDT Tue Jun 20 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0103 PM     Tstm Wnd Gst     3 SE West Melbourne     28.04N  80.64W
06/20/2023  M45 mph          Brevard            FL   Mesonet

            Mesonet site XDAI measured a 45 mph/39 kt wind gust
            from out of the west.

&&

Event Number MLB2300290

MAT

Special Weather Statement
National Weather Service Melbourne FL
216 PM EDT Tue Jun 20 2023

FLZ045-144-201845-
Orange FL-Southern Lake County FL-
216 PM EDT Tue Jun 20 2023

...A strong thunderstorm will impact portions of southwestern Lake
and southwestern Orange Counties through 245 PM EDT...

At 216 PM EDT, Doppler radar was tracking a strong thunderstorm near
Lake Louisa, or 7 miles south of Groveland, moving east at 30 mph.

HAZARD...Winds in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Ocoee, Winter Garden, Windermere, Bay Lake and Clermont.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 2851 8186 2857 8154 2835 8154 2835 8179
      2836 8179 2836 8186 2835 8186 2835 8196
TIME...MOT...LOC 1816Z 261DEG 27KT 2845 8182

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

Leahy

Special Weather Statement
National Weather Service Melbourne FL
226 PM EDT Tue Jun 20 2023

FLZ058-154-159-254-259-264-547-647-747-201900-
Southern Brevard Barrier Islands FL-Okeechobee FL-
Coastal St. Lucie FL-Inland St. Lucie FL-Inland Indian River FL-
Inland Martin FL-Coastal Indian River FL-Inland Southern Brevard FL-
Mainland Southern Brevard FL-
226 PM EDT Tue Jun 20 2023

...Strong thunderstorms will impact portions of St. Lucie,
Okeechobee, Indian River, northwestern Martin and southeastern
Brevard Counties through 300 PM EDT...

At 225 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from 8 miles east of Sebastian Inlet State Park to
Vero Beach South to Buckhead Ridge. Movement was east at 25 mph.
Additional showers and storms pushing offshore will be capable of
strong wind gusts.

HAZARD...Winds in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Fort Pierce, Sebastian, Vero Beach, Treasure Island and Okeechobee.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 2711 8066 2716 8071 2721 8081 2719 8084
      2714 8087 2719 8091 2723 8099 2730 8100
      2730 8103 2733 8105 2736 8103 2738 8108
      2783 8073 2793 8045 2747 8025 2699 8062
TIME...MOT...LOC 1825Z 264DEG 22KT 2787 8030 2759 8043 2712 8087

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

Leahy

Preliminary Local Storm Report
National Weather Service Melbourne FL
233 PM EDT Tue Jun 20 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0204 PM     Tstm Wnd Gst     1 E Valkaria            27.96N  80.53W
06/20/2023  M47 mph          AMZ552             FL   Mesonet

            Mesonet site XIND measured a 47 mph/41 kt wind gust
            from the southwest.

&&

Event Number MLB2300291

MAT

Preliminary Local Storm Report
National Weather Service Melbourne FL
239 PM EDT Tue Jun 20 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0224 PM     Tstm Wnd Gst     Vero Beach Airport      27.66N  80.41W
06/20/2023  M49 mph          Indian River       FL   ASOS

            KVRB ASOS measured a wind gust of 43 knots/49 mph from
            the west.

&&

Event Number MLB2300292

CRISTALDI

Special Weather Statement
National Weather Service Melbourne FL
245 PM EDT Tue Jun 20 2023

FLZ045-201915-
Orange FL-
245 PM EDT Tue Jun 20 2023

...A strong thunderstorm will impact portions of southwestern Orange
County through 315 PM EDT...

At 245 PM EDT, Doppler radar was tracking a strong thunderstorm over
Doctor Phillips, or near Windermere, moving east at 30 mph.

HAZARD...Winds in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Orlando, Ocoee, Windermere, Bay Lake and Azalea Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 2835 8156 2855 8155 2857 8154 2857 8118
      2835 8118
TIME...MOT...LOC 1845Z 267DEG 26KT 2845 8149

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

Leahy