283
FXUS62 KMLB 081101
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
701 AM EDT Sat Jun 8 2024

...New AVIATION...

.AVIATION...
(12Z TAFs)
Issued at 636 AM EDT Sat Jun 8 2024

VFR conditions prevail outside of convection through the TAF
package. TSRA/SHRA has developed a little ahead of schedule in
SOFL, and will need to monitor if this activity pushes north into
ECFL. Short-fused AMDs for VC timing and possibly even TEMPOs may
be needed. Added VCSH to KSUA at the start of the 12Z TAF and
continue a northward progression of VCTS starting 16Z at KSUA and
20Z at KMLB. VCTS at inland terminals ~21Z. Clearing out by 03Z.
All that said, TSRA should be ISO to SCT at best so not committing
to TEMPOs with the 12Z package. Light SW-W winds will once again
favor the WCSB, reaching KLEE ~19Z and KISM/KMCO/KSFB ~22Z,
increasing W winds to 10-15 kts. Delayed ECSB reaches the coastal
terminals between 16Z-20Z, earlier to the south and later to the
north, shifting winds ESE- SE 10-15 kts with occasional gusts to
20 kts. ECSB/WCSB collision expected just west of the I-95
corridor ~22Z.

&&

.PREVIOUS DISCUSSION...
Issued at 445 AM EDT Sat Jun 8 2024

Key Messages:

-Hot conditions through the weekend and into early next week with
 heat index values 100 to 108+

-Slightly lower rain and storm chances through Monday, increasing
 and becoming more widespread toward the middle of next week

-Fire sensitive to near critical fire weather conditions each
 afternoon

Today-Tonight...Temperatures are starting a couple to a few
degrees warmer in spots when compared to Friday morning. Water
vapor imagery uncovers a swath of dry air sinking south across the
northern and central part of the state. Recent RAP analysis
indicates significant drying above 500mb, aligning with GOES-
derived PW of 1.5" or less from Orlando northward. This sector of
drier air will play a role in lowering rain chances across the
northern half of the area today and tomorrow. As a result, more
sunshine will push temperatures toward daily records at Leesburg,
Sanford, and potentially one or two more sites. Highs this
afternoon will top out in the mid to upper 90s, except where the
sea breeze keeps temperatures a couple degrees cooler at the
coast. Heat index values of 100 to 107 will be common when
unimpeded by storms and associated cloud cover. Therefore, today`s
HeatRisk is moderate to major, meaning this level of heat can
affect anyone without effective cooling and/or adequate hydration.
If outdoors, take frequent breaks from the sun in shaded or air
conditioned spaces and remain well hydrated.

Rain and lightning storm chances increase from midday onward and
will be focused from near Orlando and Melbourne south toward Lake
Okeechobee and the Treasure Coast. This is where a collision of
the Lake O and west/east coast sea breezes is expected to occur.
Additional outflow boundaries from early-onset storms will enhance
convective initiation farther south. A conditional threat for
strong gusty winds exists, due to the drier mid levels and
resultant DCAPE values (1200-1400+ J/kg) portrayed on CAM
soundings. Coverage of storms will be scattered at most, with
generally slow and erratic motion due to weak steering flow and
boundary collisions. PoPs were kept in the "chance" category for
now, due to lower confidence in the overall evolution. Activity is
forecast to dissipate shortly after sunset with any lingering
showers translating offshore.

Sunday-Monday...Temperatures heat up even more Sunday and Monday
with heat index values approaching or eclipsing Heat Advisory
criteria (108+). An advisory will need to be considered for
portions of east central Florida, especially if temperature
trends go largely unchanged. With highs in the mid to upper 90s,
it would not be out of the question to see a few locations hit the
100 degree mark, especially on Monday. Combined with warm
conditions each night (lows in the mid to upper 70s), this level
of prolonged heat has the ability to affect anyone without
effective cooling or adequate hydration. Check on those who are
most vulnerable, including the elderly and those without air
conditioning, and never leave kids or pets unattended in a
vehicle!

The chance for rain and storms on Sunday is a near carbon copy of
today`s, with the highest PoPs (40 to 55 percent) focused south.
By Monday, moisture return increases from the south and leads to
greater coverage of afternoon and evening storms. The QPF during
this timeframe ranges from a few hundredths of an inch north of
Interstate 4 to as much as one inch or more around Lake
Okeechobee. Locally higher amounts of rain are certainly possible,
especially given the slow and erratic movement of storms. One
limiting factor will be the duration of sustained updrafts, which
may not be more than 20 to 30 minutes at a time, given weak mid
level lapse rates. Convective initiation will be more closely
tied to the inland moving sea breezes and eventual collisions
over the interior. By sunset or shortly after, most of the rain
will be coming to an end.

Tuesday-Friday...At this point in the forecast, rain chances
increase areawide. Synoptically, stout mid level ridging unfolds
across the southwestern U.S. as the northern stream gets cut off
from the central and southern states. Surface high pressure
settles in over the Mid Mississippi and Ohio Valleys Tuesday into
Wednesday as a cool front pushes into north Florida. This front
becomes modified and stalls across north FL, thanks to southerly
WAA. As a lobe of mid level energy approaches the central Gulf
Coast Wednesday into Thursday, tropical moisture and shortwave
energy is advertised to rotate northward from the Yucatan and
western Cuba.

All of this combined will result in waves of rain and lightning
storms, with coverage maximized during the daytime. Model
differences remain in regard to the placement of the highest rain
totals, with a large spread from the eastern Gulf of Mexico to
south- central Florida. Among global models, the GFS, CMC, and EC-
AIFS are situated farther east, encompassing much of the peninsula
in 1-4"+ of accumulated rainfall, while the ECMWF and ICON place
the heaviest rains over the Gulf and Florida Panhandle. Any rain,
but especially the higher end amounts, would benefit the current
drought conditions. Overall, expect an increasingly unsettled
weather pattern from Tuesday onward. Details on day-to-day storm
chances and QPF will become clearer late this weekend into
Monday.

Another benefit to increasing rain chances is the associated cloud
cover and lower daytime temperatures. Highs in the low to mid 90s
Tuesday are forecast to drop back into the mid to upper 80s
Wednesday-Friday. Overnight lows stay rather mild, however, in
the 70s areawide.

&&

.MARINE...
Issued at 445 AM EDT Sat Jun 8 2024

Today-Tonight...Favorable boating conditions outside of isolated
storms are forecast with 1-2 ft seas and early W winds backing SE
in the afternoon. Speeds increase to around 15 kt this evening
and tonight before decreasing by sunrise Sunday. Isolated showers
and lightning storms will tend to be focused from Cape Canaveral
southward, where slightly greater moisture is present.

Sunday-Wednesday...WSW surface flow continues thru midweek with
winds backing SE and increasing to 15-17 kt each afternoon/evening
behind the sea breeze. Generally favorable boating conditions are
expected, though the chance for locally heavy rain and lightning
storms increases from Monday-Tuesday onward. Seas 2-3 ft, except
where locally higher in the vicinity of lightning storms.

&&

.FIRE WEATHER...
Issued at 445 AM EDT Sat Jun 8 2024

Above normal temperatures through the weekend and into early next
week, along with persistent drought conditions and lower
relative humidity values each afternoon, will lead to fire
sensitive or near critical conditions. Fire concerns will be
locally enhanced by the daily afternoon sea breezes and isolated
to scattered lightning strikes. Moisture increases next week,
leading to greater coverage of rain and lightning storms.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  95  75  97  74 /  20  20  20  10
MCO  97  77  96  76 /  30  20  30  10
MLB  93  76  93  76 /  30  20  40  20
VRB  94  74  93  76 /  40  20  40  20
LEE  97  76  97  76 /  30  10  20   0
SFB  96  76  97  76 /  30  20  30   0
ORL  97  77  96  77 /  30  20  30   0
FPR  93  74  93  75 /  40  20  40  20

&&

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

$$

DISCUSSION...Schaper
AVIATION...Haley