Haines Creek, Florida Weather Forecast Discussion

831
FXUS62 KMLB 170729
AFDMLB
Area Forecast Discussion
National Weather Service Melbourne FL
329 AM EDT Wed Sep 17 2025
...New DISCUSSION, MARINE...
.KEY MESSAGES...
Issued at 326 AM EDT Wed Sep 17 2025
- Coverage of rain and lightning storms will gradually increase
  from south to north today into late week; locally heavy
  rainfall possible across the Treasure Coast Thursday into Friday
- Temperatures remain near to slightly below normal this week and
  into early next week, especially across the south, where higher
  coverage of clouds and rain are forecast
- A moderate risk of life-threatening rip currents will exist at
  all area beaches today, always swim near a lift guard
&&
.DISCUSSION...
Issued at 326 AM EDT Wed Sep 17 2025
Today-Tonight...  The cutoff low aloft centered over NC/VA will
gradually lift northeastward and will merges into a trough digging
southward from Canada by late today into Thursday. At the surface,
the low pressure near NC/VA will continue to slowly shift
northeastward through the day, dragging a surface boundary across
the Florida peninsula into tonight. Locally, NE winds 5-10 mph will
become more easterly and increase to 10-15 mph in the afternoon
behind the east coast sea breeze. Deeper moisture will continue to
build northward across the local area, with forecast PW values
rising to near 2" from around Melbourne southward (with PW values
~1.7-1.8" along and north of I-4 corridor). Due to this surge in
moisture, rain chances will also increase across the area today. The
highest rain chances (50-60 percent) will occur from around
Melbourne to Orlando southward this afternoon and evening, with 30-
40% chance occurring northward. While lightning storm activity will
be on the rise from the last day or so, overall lightning storm
activity will continue to be somewhat limited due to the lower
instability (CAPE less than 1000 J/kg). Having said that, isolated
to scattered lightning storms are forecast this afternoon and early
evening.
The locally heavy rainfall threat will also begin to increase today,
due to slow storm motions (around 10 mph or less) and repeated
rounds of showers and storms. The main storm hazards will be
occasional to frequent lightning strikes, wind gusts 40-50 mph, and
locally heavy rainfall. While locally heavy rainfall will be helpful
for the continued drought conditions along the Treasure Coast, this
could set the stage for a greater flooding rainfall threat late
week, especially in areas that see multiple rounds of heavy rainfall
over several days. Tonight, rain and storm chances will continue
through the overnight hours. There is a low to medium (20-60
percent) chance of rain across much of the area, with the greatest
chance occurring from Melbourne southward along the coast.
Temperatures will remain near to slightly below normal due to the
high cloud cover as well as the onshore flow. Afternoon highs will
be in the mid to upper 80s. Overnight lows will continue to be in
the low to mid 70s.
Thursday-Wednesday... The mid-upper level trough axis across the
eastern US on Thursday will gradually shift eastward into the
Atlantic as a low pressure over Canada deepens and moves eastwards
towards Quebec and the far northeast US into the weekend and early
next week. The aforementioned surface low pressure will move
northeast off of the New England coast and open into a trough.
Deeper moisture will continue to build northward across the Florida
peninsula each day, with a surface boundary settling near to just
south of the local area late week into early weekend. This boundary
will shift southward just off the Florida peninsula/across the
Florida Keys late weekend before shifting back northward across
South Florida into early next week. Current model guidance shows
this boundary washing out mid week.
The greatest potential for locally heavy rain fall continues to be
Thursday into Friday as forecast PW values increase to 1.8-2.0" from
around Melbourne southward, with comparably drier air ( PW values of
1.5"-1.7") farther inland and northwest. The highest coverage of
showers and storms on Thursday looks to be from around Melbourne
southward and towards Okeechobee County, and particularly along and
the Treasure Coast. This may help put a dent in the drought
conditions across portions of the Treasure Coast. However, with
training of showers and locally heavy rainfall, minor flooding
concerns remain for Thursday across the Treasure Coast despite the
dry antecedent conditions.
Despite increasing moisture from south to north, models continue to
show a moisture gradient persisting over the area. Thus, even with
PW values increasing north and west of I-4 through early next week,
the PW values will remain below the values across the south. Because
of this, a gradient for rain chances will exist. A medium chance
(60-70 percent) chance of rain and lightning storms are forecast
south of Melbourne and towards Okeechobee each day through early
weekend, with 30-50 percent chance to the north and west. Rain
chances expand slightly on Sunday with 60 percent along the coast,
and 40-50 percent across the interior before rain chances become 40-
50 percent area wide early next week into mid week. Exactly where
this gradient into the weekend develops, however, will be dependent
on the location of the boundary. Onshore flow will persist through
the time period, with speeds increasing to 10-15 mph behind the sea
breeze each afternoon. Temperatures will remain near to slightly
below normal through the weekend, especially where added cloud cover
prohibits more efficient daytime heating. Afternoon highs will be in
the mid to upper 80s to near 90 degrees through the weekend,
increasing to upper 80s to low 90s into early next week.
&&
.MARINE...
Issued at 326 AM EDT Wed Sep 17 2025
Today-Sunday... Favorable boating conditions forecast into the
weekend. Northeast winds will become more easterly into mid to late
week with speeds around 10-12 KT today. Wind speeds will increase to
10-15 KT late week and into the weekend, as a surface boundary
reestablishes itself near to just south of the local waters. Seas 3-
5 ft prevailing through the weekend. Isolated showers and storms
will largely be confined to the Gulf Stream and southern Treasure
Coast waters through today, until deeper moisture brings higher rain
and isolated lightning storm chances late week and into the weekend.
&&
.AVIATION...
(06Z TAFs)
Issued at 140 AM EDT Wed Sep 17 2025
VFR will continue for most sites thru at least 18z, though brief
MVFR/IFR cannot be ruled out prior to 13z-14z from MLB southward
due to coastal SHRA/TSRA. Guidance is inconsistent but will
maintain general VC wording for most sites after 18z. The focus
for SHRA/TSRA impacts will be on inland sites 18z-00z, followed by
pushback toward the coast thru the end of the TAF. TEMPOs may be
needed but will wait to introduce those until the 12z TAF, at
earliest. NE winds thru 13z, generally 5-10 kt or less, speed up
to 10 kt inland (up to 14 kt at the coast) after 15z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB  85  72  86  73 /  30  20  30  20
MCO  87  72  88  73 /  50  30  40  20
MLB  85  74  85  75 /  60  50  60  40
VRB  85  73  86  75 /  60  60  70  60
LEE  87  72  88  72 /  40  20  30  10
SFB  87  72  87  73 /  50  20  40  20
ORL  87  73  87  73 /  50  30  40  20
FPR  85  73  85  73 /  60  60  70  60
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
DISCUSSION...Watson
AVIATION...Schaper

NWS MLB Office Area Forecast Discussion