392
FXUS62 KMLB 100825
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
425 AM EDT Fri May 10 2024

...New DISCUSSION, AVIATION, MARINE, FIRE WEATHER, CLIMATE...

.DISCUSSION...
Issued at 425 AM EDT Fri May 10 2024

Key Messages:
-Unusually hot today; breezy with critical fire weather
conditions for the Treasure Coast and Lake Okeechobee region.

-One or two strong storms possible today and this evening, mainly
north of Kissimmee to Melbourne, as a cold front approaches.

-Increasing potential for much-needed rain next week, but this may
be accompanied with a threat for strong to severe storms.

Today-Tonight...A very tricky forecast for the next 24 hours,
especially in regards to rain chances and stronger storm potential.
Passing mid-level disturbance across the southeast U.S. today,
should continue to fuel a MCS north of the area that will drop
toward north central FL later this morning into the early afternoon.
The HRRR has been the most robust with this convection across
northern portions of east central FL, but recent runs of this model
have trended downward with coverage with this activity as it nears
Lake and Volusia counties. An outflow boundary from this system
looks to enter into the area and stall and could be focus for
additional shower/storm development across northern portions of
east central FL later into the afternoon, with any additional
storms shifting quickly offshore. One final round of showers and
storms will then be possible along the cold front that will drop
southward into central FL this evening and overnight. Rain chances
range from 20-40 percent from Orlando area to the Cape northward
today and also have slight chance PoPs along along the coast from
southern Brevard and Indian River counties. Into tonight, rain
chances range from 30- 40 percent from Orlando to Cape northward
and 20 percent to the south.

A conditional threat for strong to isolated severe storms will exist
with any storms that develop today into tonight across northern
portions of east central Florida. Sufficient instability (SBCAPE of
1000-1500 J/kg), cooler temps aloft of -9 to -10C at 500mb, and
increasing westerly flow up to 35-40 knots at 850-700mb will
allow any storms that develop to have the potential to produce
strong wind gusts up to 40 to 50 mph and small hail. However, an
isolated threat for locally damaging wind gusts up to 60 mph and
quarter sized hail will also exist. SPC has a Slight Risk
extending southward into northern Lake and Volusia counties, with
a Marginal Risk southward toward a Melbourne to Lake Kissimmee
line.

It will be another hot day across the area, with breezy W/SW winds
this afternoon. Highs are forecast to reach near record values, in
the mid to upper 90s over much of the area, except low 90s across
northern portions of Lake and Volusia counties. A drier airmass will
keep maximum heat index values limited to around 98-103 degrees,
which is below heat advisory criteria (heat index values of 108+).
However, this level of heat for this time of year will affect anyone
working outside and/or those in direct sunlight for extended periods
of time. Remember to take frequent breaks and stay hydrated,
especially if you are spending extended periods outside this
afternoon. Temperatures drop into the 80s this evening, with
overnight lows falling to the low to mid 70s as a weakening cold
front begins to move southward across the area.

Synoptic Overview For Saturday Through Next Friday...

This weekend, a trough will reside across the Northeast U.S. Its
attendant cold front will slip southward toward South Florida on
Saturday, and high pressure will quickly follow behind. Shortwave
ridging will slide across the Gulf on Sunday before pushing into the
Atlantic by late Monday. By Tuesday, yet another trough will move
into the Mississippi Valley. In response, southerly flow will become
reestablished early in the work week, surging warm and moist air
northward. The interaction of this warm, humid air mass with the
perturbations within the trough should promote rounds of showers and
storms along the Gulf Coast and portions of Florida during the
early/middle parts of the week. Once this trough exits, ensemble
guidance then suggests that mid-level ridging will amplify from the
Bay of Campeche to the Bahamas late next week. Within this pattern,
the primary concerns will be the potential for strong storms and
periods of well-above-normal temperatures.

Sensible Weather & Impacts:

This Weekend...

We will wake up early Saturday with a cold front moving southward
through the peninsula. The timing and positioning of this boundary
will be dictated by not only its parent trough but also earlier MCS
activity and outflow boundaries. Statistical guidance hangs onto 20-
30% chances for showers and storms mainly for the Treasure Coast &
Okeechobee areas on Saturday. The primary threat from any storm that
manages to form would be gusty winds of 40-50 mph. Drier air will
quickly filter across the rest of the area, with dew points dropping
to the upper 50s to mid 60s. It will still be warm to hot, with
highs 85-88 along the coast warming to the low 90s near Orlando and
mid 90s down close to Lake O. Sunday starts "cooler" with 60s in
most places, but by afternoon similar temperatures to Saturday are
forecast. Sunday should be rain-free as the relatively dry air holds
sway for one more day.

Monday-Wednesday...

This continues to shape up as our most active stretch of weather.
09/12Z ensemble cluster guidance continues to indicate improving
confidence in the timing of the next trough emanating from the
Plains into the Mississippi Valley. Over 75% of members are now
linked up with impacts for at least the northern half of Florida.
There appear to be multiple opportunities for showers and storms.
While this is needed rain, some storms could turn strong to severe.

On Monday, southeasterly flow sets up ahead of the feature, dragging
in higher Theta-E values. Guidance thinks this is sufficient to
allow widely scattered afternoon showers and storms to develop.
There is a non-zero strong/severe storm threat as early as Monday:
CAPE weak to moderate at best (500-1500 J/kg), but shear values will
be increasing due to a backed profile in the boundary layer and a
strengthening subtropical jet. The primary hazards here appear to be
gusty winds and perhaps one or two tornadoes. Highs on Monday will
climb to the mid/upper 80s on the coast to the low 90s interior.

From Monday night into Tuesday, disturbances within the base of the
shortwave trough are likely to spawn rounds of showers and storms
along the I-10 corridor, perhaps in the form of strong MCS/QLCS
segments. One or more of these features could turn toward our
forecast area as they hug any theta-E gradients. With the mass
response expected ahead of this trough, both thermodynamic and
kinematic indicators look to become more favorable for severe
weather. The EPS CAPE & CAPE/SHEAR EFIs continue to increase during
this period, from 0.7 to 0.9 with some shift-of-tails indicating a
potentially volatile parameter space for storm sustenance. Depending
on the timing, all hazards, including large hail, could be on the
table during this period. These threats will likely increase as one
travels northward across our district. Integrated vapor transport
values are projected to exceed the 99th percentile across much of
the area, so any training storms would pose a localized flooding
threat as well.

The wind profiles become increasingly unidirectional from late
Tuesday into Wednesday as the shortwave moves to our northeast.
While its front is not expected to get down here, multiple outflow
boundaries beneath an active subtropical jet could yield additional
rounds of showers and storms into Wednesday. Severe weather will
remain possible.

One reminder: while the broad strokes of this pattern currently look
concerning, we are several days out and a lot can (and will) change.
We will keep you up to date on the forecast as we fine-tune the
details.

For Tuesday and Wednesday, upper 80s are forecast north of I-4 with
low 90s from Orlando to the Space Coast. The boundary layer will
remain warmer than normal, with some potential for heat impacts over
areas that remain unimpeded by rain and storms. The Treasure Coast
and Lake O region could end up hotter, in the mid 90s.

Thursday-Next Friday...

As mentioned before, guidance shows no clear-cut frontal passage
with the mid-week disturbance, leaving warm and humid air in place.
We should hang onto a southerly wind component later next week as
heights build ahead of another trough up across the Plains. A few
mainly diurnally-driven storms remain possible each day. Anomalously
warm H85 T`s are forecast by NAEFS members to exceed the 95th
percentile of climatology. Unsurprisingly, statistical guidance
shows widespread 90s late next week, perhaps closing in on the
extent of heat we`re feeling right now.

&&

.AVIATION...
(06Z TAFs)
Issued at 425 AM EDT Fri May 10 2024

Some areas of stratus will be possible across the area this
afternoon, producing IFR/MVFR conditions. However, this lower cloud
cover should diminish into late morning. Showers and isolated storms
may approach Lake/Volusia counties from late morning into early
afternoon, but should then diminish in coverage. A outflow boundary
pushing southward into north central FL may initiate additional
showers and storms this afternoon, with another band of convection
possibly forming along a southward moving cold front into tonight.
Some strong to isolated severe storms may be possible with any of
this activity, but overall confidence in stronger storms and overall
rain chances remains low. For now, have limited any mention to
VCSH/VCTS in the TAFs. W/SW winds increase to 10-15 knots this
afternoon, with gusts to 20-22 knots. Winds then decrease to 5-10
knots overnight.

&&

.MARINE...
Issued at 425 AM EDT Fri May 10 2024

Today-Tonight...An approaching cold front from the north will keep
ridge axis of high pressure over the west Atlantic south of the
waters today, with the front then pushing southward through the area
tonight. W/SW winds up to 10-15 knots become S/SW into the afternoon,
with wind speeds continuing to increase up to 15-20 knots offshore
out of the W/SW into tonight. Seas 2-4 feet, increasing up to 5
feet offshore late tonight.

Saturday-Monday... Generally favorable boating conditions this
weekend. A cold front will settle into South Florida on Saturday,
with high pressure in its wake that will push off into the Atlantic
by Monday. Isolated storms are possible over the waters on Saturday
south of Sebastian Inlet and for all of the local waters by Monday
afternoon as moisture increases. A sea breeze should form both
afternoons this weekend, with afternoon winds becoming NE to E from
10-15 KT. By Monday, winds increase out of the SE, 12-17 KT during
the day. These winds may freshen further, approaching advisory
territory by Monday night ahead of a weather disturbance.

&&

.FIRE WEATHER...
Issued at 425 AM EDT Fri May 10 2024

Today...Hot conditions, breezy W/SW winds and some lingering drier
air will produce elevated fire weather concerns today. A Red Flag
Warning has been issued for Indian River, St. Lucie and Okeechobee
counties, where lowest Min RH values of 30-35 percent are forecast,
and where winds look to be just strong enough, around 15 mph, for
Red Flag conditions to be met. Farther north, min RH values will
range from the upper 30s to mid 40s, with breezy W/SW winds
forecast.

Saturday-Monday... Fire-sensitive to near-critical conditions at
times this weekend away from the coastal corridor. WNW winds of 10-
15 mph will deliver a punch of drier air down the peninsula for
Saturday, with only a 20-30% storm chance lingering for the Treasure
Coast and Lake O region. Across the interior, RH minima will fall to
33-38% on both Saturday and Sunday afternoons. By Sunday, winds turn
to the NE 5-15 mph, strongest along the coast where a sea breeze is
forecast. Localized critical conditions are possible on Saturday
afternoon, especially from Clermont to Okeechobee (the Kissimmee
basin). Winds turn toward the southeast from 10-15 mph on Monday,
locally gusting to 20 mph along the coast. This will carry an
increase in moisture and a chance for afternoon showers and storms.
Wetting rain chances increase, especially across the northern half
of Central Florida, from late Monday through mid-week.


&&

.CLIMATE...
Issued at 425 AM EDT Fri May 10 2024

Highs will be well above normal today, reaching the mid to upper 90s
for most locations, except low 90s across northern Lake/Volusia
counties. Melbourne, Vero Beach and Fort Pierce are currently
forecast to tie/break their record highs for today, but Daytona
Beach will also be close.

Record Highs for Today, May 10th and Last Year Set:

            MAY 10TH
Daytona     94 2008
Leesburg    96 2009
Sanford     98 2009
Orlando     98 1916
Melbourne   95 1978
Vero Beach  95 1976
Ft. Pierce  96 2008

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  93  70  85  66 /  40  30   0   0
MCO  95  74  92  67 /  20  30  10   0
MLB  95  72  88  70 /  20  20  10   0
VRB  97  71  90  68 /  20  20  20   0
LEE  92  73  90  67 /  30  40  10   0
SFB  95  73  91  67 /  30  30  10   0
ORL  94  73  92  68 /  20  30  10   0
FPR  97  70  91  67 /  10  20  20   0

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...Red Flag Warning from 1 PM this afternoon to 7 PM EDT this
     evening for FLZ058-154-159-254-259.

AM...None.
&&

$$

SHORT TERM...Weitlich
LONG TERM...Heil
AVIATION...Weitlich