Deltona, Florida 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

781
FXUS62 KMLB 221208
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
708 AM EST Sun Dec 22 2024

...New AVIATION...

.KEY MESSAGES...
Issued at 406 AM EST Sun Dec 22 2024

- Chilly again this morning, then gradually warming through the
  week with isolated to scattered onshore moving showers.

- There is a low but non-zero chance for locally heavy rainfall
  later late this afternoon into tonight.

- Atlantic boating conditions remain marginal at best close to
  shore, becoming poor to hazardous further out through mid-week.


&&

.PREVIOUS DISCUSSION...
Issued at 406 AM EST Sun Dec 22 2024

This Morning...Northwesterly flow early this morning continues
all the way to the coast. Hi-res guidance indicates winds along
the barrier islands could turn onshore near sunrise, providing a
subtle early morning warm-up, but for everyone else another chilly
start to the day is in store. Temperatures at 4 AM are ringing in
from the L40s north of I-4, to the M-U40s across the rest of the
interior, and in the M40-L50s along the coast. Should see
temperatures drop a couple more degrees before sunrise, with the
5-10 mph breeze pushing wind chills into the U30s-L40s across most
of the area, save for the southern coast in the L40s-50. A few
showers continue across the Atlantic waters, but will stay
offshore for now.

Today-Tonight...High pressure dominating the eastern half of the
CONUS shifts east, with the center reaching near the New England
seaboard by Monday morning. The southern flank of the high becomes
draped across Florida, while an inverted surface trough develops
over the nearby Atlantic waters. Still pretty good consensus this
trough will track towards the Florida east coast, but where and
how much rain the trough will bring to the coast is a
disappointing question mark for a 12-hour forecast. Rainfall
amounts in the CAMs are spread fairly wide, ranging from only
0.50" bulls-eyes in the very pessimistic 00Z HRRR, to 1.0-2.0"
across much of the Space Coast and into parts of the Treasure and
Volusia Coasts, with locally high amounts up to 4" possible in the
very excited NAM 3km. The ARW and FV3 are fairly close to each
other about midway between the other models, supporting a
consensus forecast. As such, the official forecast follows the
HREF mean, calling for rainfall amounts generally less than 0.50",
however, WPC has indicated there is a less than 5 pct but non-
zero chance for excessive rainfall mainly along the Space Coast
based on the higher-end guidance. The limiting factor is PWATs,
which are forecast to remain less than an inch through most of the
day, only increasing to more than 1" late tonight, and the GFS
and ECM can`t even agree where those higher values will be. The
00Z GFS has decided to take the trough and higher moisture further
north, closer to Jacksonville, while the ECM stays closer to our
area. Ultimately looks like most of the rain that makes it to
shore during the day should be fairly light, with the best chances
for heavier showers in the evening and overnight periods.

As for the rest of the forecast, the trough veers north-
northwesterly winds at 5-10 mph in the morning to north-
northeasterly (onshore) at around 10 mph inland and 10-15 mph with
gusts to 20 mph along the coast by the late afternoon. The
Volusia and northern Space Coasts could get briefly breezy and
gusty with winds over 15 mph and gusts up to 25 mph. Afternoon
highs remain a bit on the cooler side in the M60s-L70s.

Monday-Tuesday...The large picture remains relatively unchanged,
with the southern flank of high pressure remaining draped across
Florida while being elongated and contorted by multiple low
pressure systems to the north. But closer to our neighborhood,
there`s been a fairly big shift in guidance from this time
yesterday. The GFS and ECM are now both developing the trough into
a low off the FL-GA-SC coasts, lifting away much of the moisture
that had been previously forecast to remain anchored along the
Florida east coast through mid-week. Some disagreement on timing
as the more aggressive GFS develops a closed low by Monday, while
the slower ECM follows on Tuesday. Our forecast rain chances have
come down as a result, especially Monday`s, but modest onshore
flow and a sufficiently deep marine layer should still support
shallow isolated to scattered showers (PoPs 20-30 pct). The 06Z
HRRR has finally come in, keeping the tail of the trough and
associated moisture axis closer to our coast, which is in line
with the EC-AIFS/ECM and making the GFS more of an outlier. Thus,
wouldn`t be surprised if forecast rain chances for Monday came
back up a bit in upcoming forecast packages.

As for the rest of the forecast, winds become a bit shifty Monday
and Tuesday depending where the trough is, ranging from northerly
to easterly at 10 mph or less. Monday morning lows around normal
in the 50s, maybe slightly above, ticking up to above normal in
the M50s-M60s Tuesday morning. Afternoon highs Near normal in the
L-M70s, both Monday and Tuesday.

Christmas Day-Saturday...Latest model guidance is out to lunch by
this point. Overall we remain under the influence of high pressure
over the eastern US and ridging aloft, but the Southeast US just
becomes a mess of weakly forced surface weather systems. EC-AIFS
and ensembles call for an overall gradual transport of moist
tropical air through the period, continuing the warming trend and
supporting broad 20-30 pct rain chances despite ridging aloft
keeping the environment well capped. Thunder has been all but
removed from the forecast at this point, with just some low
chances over the Atlantic waters, putting any wishes for a
Christmas Day lightning storm on the ropes.

&&

.MARINE...
Issued at 406 AM EST Sun Dec 22 2024

Boating conditions remain unfavorable to hazardous through late
Tuesday, with some improvement possible by mid-week. High pressure
over the eastern US will shift out to sea through the first half
of the week, with the southern flank draped across Florida and the
local Atlantic waters. A surface trough will move into the local
waters, resulting in generally northeasterly winds 10-15 kts today
as the trough approaches, though winds up to 20 kts north of the
Cape will be possible in the late afternoon and evening. Winds
then become shifty at 5-15 knots, occasionally over 15 kts, Monday
and possibly into Tuesday as the trough meanders east and west
while slowly lifting north. Easterly flow at 10-15 kts, once again
occasionally over 15 kts, becomes more established Wednesday
onward as the trough departs. Through Wednesday nearshore seas
remain generally 3-5 ft, occasionally up to 6ft beyond 10 nm,
while seas in the Gulf Stream 4-6 ft pick up to 7 ft this evening
and possibly into Tuesday. Seas finally begin to settle for a
couple days Wednesday and Thursday, from 3-5 ft to 2-5 ft.
Isolated to scattered showers are expected through the period,
with the highest chances generally today and Monday. Isolated
lightning storms will be possible Tuesday onward.

&&

.AVIATION...
(12Z TAFs)
Issued at 708 AM EST Sun Dec 22 2024

Mainly VFR conditions are forecast through 21Z. TEMPO groups for MVFR
CIGs exist between 17Z-21Z at KDAB, KTIX, & KMLB. Prevailing MVFR CIGs
are forecast at the coastal TAF sites after 21Z-22Z with the potential
for MVFR CIGs at times at the inland TAF sites into this evening. VCSH
is forecast into the PM. WNW winds are forecast to increase after 14Z-16Z
at around 10-12kts with gusts to 15-18kts before weakening after 03Z.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  66  55  70  55 /  20  40  30  30
MCO  68  55  73  56 /  10  30  20  10
MLB  70  59  74  59 /  30  30  30  20
VRB  72  59  76  60 /  30  30  20  20
LEE  66  51  71  54 /  10  20  10  10
SFB  68  54  73  55 /  20  40  20  20
ORL  69  55  73  57 /  10  30  20  10
FPR  71  59  76  59 /  20  20  20  20

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory from 10 AM this morning to 10 PM EST this
     evening for AMZ550.

     Small Craft Advisory from 10 AM this morning to 4 PM EST Monday
     for AMZ570.

     Small Craft Advisory from 10 PM this evening to 4 PM EST Monday
     for AMZ572.

&&

$$

DISCUSSION...Haley
AVIATION...Fehling