Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus62 kmlb 150817 

Area forecast discussion
National Weather Service Melbourne Florida
416 am EDT sun Sep 15 2019


..Humberto brings hazardous boating and surf conditions...

Current-today...Tropical Storm Humberto was located about 190 miles
east of Vero Beach at 11 PM and moving north-northwest at 6 mph. Humberto is
forecast to continue to move north-northwest into this afternoon and evening
well offshore from the space coast and Volusia County later today.
Gradual strengthening is forecast and Humberto could become a
hurricane by this evening. Northerly winds on the back side of
Humberto will elevate seas across the Atlantic, with high surf
expected north of Sebastian Inlet and a high risk of rip currents
for east central Florida beaches. As Humberto lifts northward, winds
will become northwest from Melbourne south to the Treasure Coast
with gusty north/north-northeast winds along coastal Volusia County where breezy
conditions are expected. Onshore moving showers are expected north
of the cape with short range model guidance indicating a detached
convective band may develop across southern portions of east
central Florida this afternoon. Will have higher pops in the likely range
for coastal and srn sections and scattered convective chances for
Lake County. Highs will range from around 86 along the Volusia coast
and near 90 across srn sections and the interior.

Tonight...Humberto is expected to begin to turn NE tonight well
offshore from the Volusia County and NE Florida coast. Scattered evening
convection may linger across far southern sections and then expect
only a slight shower chance for coastal sections mainly north of the
cape overnight. Lows generally in the mid 70s to the upper 70s at
the beaches.

Monday...tropical cyclone Humberto will continue to slowly move
further away from Florida. We will be on the backside of the storm's
circulation with northwesterly to northerly flow across central Florida.
A tight moisture gradient is forecast to develop from west to east,
with higher rain chances along the coast. Models continue to show
scattered showers and maybe an isolated lightning storm or two
moving onshore in the afternoon. Temperatures remain near normal
with afternoon highs around 90-91 degrees and overnight lows in the
low to mid 70s.

Tuesday-Wednesday...winds transition to a more onshore (north-
northeast) component. Expect mostly dry conditions Tuesday due to
considerable dry air in the low levels of the atmosphere. Some
models hint at a few showers developing west of I-95 in the Treasure
Coast, but conditions may be too dry even for that. On Wednesday, a
weak elongated shortwave trough will quickly move south from the
Carolinas towards the Florida Peninsula. While this feature may enhance
rainfall, though there is considerable uncertainty regarding exactly
how strong it will be. For now, have capped rain chances at 30
percent for Wednesday afternoon. Temperatures should remain near
normal for this time of year.

Thursday-Saturday...Stout northeasterly flow is forecast to develop
by Thursday as the pressure gradient between tropical cyclone
Humberto in the western Atlantic and a developing ridge over the mid-
Atlantic states increases. Forecast soundings indicate precipitable water values
below 1.50" which would be remarkably dry for this time of year.
Again uncertainty remains high, GFS shows a quick return of deeper
moisture by the late afternoon, while the European model (ecmwf)/CMC keep conditions
much drier. Thus, rain chances are once again conservatively capped
at 30 percent. The stronger onshore winds will keep temps on the
cooler side of normal with mid 80s along the coast and upper 80s

By Friday, a deep ridge builds in across the eastern Continental U.S. As winds
veer east-northeasterly here in central Florida. Precipitable water values are forecast
to increase, and with Stout onshore flow expect a stream of
scattered showers during the afternoon hours. This trend will
continue into the weekend with a 30-40 percent chance of showers
each day.


isolated to scattered onshore moving showers are expected mainly
north of kmlb before sunrise reaching into the interior from
ksfb_kmco at times. Have continued some rain showers chcs nrn terminals
through late morning and early afternoon and then vcsh. From kmlb
south along the coast, should see scattered rain showers/thunderstorms and rain develop into
mid to late afternoon and move toward the East Coast into early
evening. Precip chances should mainly end by 02z, except a linger
cstl rain showers chance from kdab-ktix overnight.


today...Tropical Storm Humberto will move north-northwest offshore from east
central Florida with center forecast to remain about 170-180 miles
offshore. The pressure gradient will expand some as the system
deepens later today and expect winds to increase to at least 25
knots across the nrn offshore waters with some gusts to 35 knots
well offshore. Winds will not be as strong across the srn waters to
15-20 knots but higher swells will linger offshore and at times
reach the southern near shore waters. Will continue Small Craft Advisory all areas
with seas building to 10-12 ft across the offshore waters north of
Cape Canaveral. Seas south of Sebastian Inlet will range from 5-7 ft
near shore to 6-8 ft offshore.

Tonight...N/NW winds will continue tonight strongest across the well
offshore Volusia waters to 25 knots with gusts to 35 knots. Seas
will remain hazardous offshore from 10-12 ft across the offshore
waters north of Cape Canaveral to 7-9 ft across the srn offshore
waters. Will continue Small Craft Advisory headlines for all of the

Monday-Thursday...marine conditions remain hazardous for small
crafts this week. Sustained northerly winds are forecast between 15-
20 knots with higher gusts. Even as Tropical Storm Humberto
continues to move away from the area, the storm will continue
generating large swells across the waters east of Florida. Seas are
forecast to be 6-7 feet nearshore and up to 8 feet offshore. These
winds going against the Gulf Stream may lead to locally higher seas
farther offshore. Drier conditions are expected early in the week
before winds veer onshore on Wednesday with an increase in
shower activity.


Preliminary point temps/pops...
dab 86 76 88 76 / 60 30 40 10
mco 90 75 91 75 / 60 10 40 10
mlb 90 75 89 77 / 60 20 40 10
vrb 89 75 90 75 / 60 30 40 20
Lee 90 74 92 75 / 40 10 30 10
sfb 89 75 91 74 / 60 20 40 10
orl 90 75 91 75 / 60 10 40 10
fpr 89 75 91 75 / 70 40 40 20


Mlb watches/warnings/advisories...
Florida...high surf advisory until 5 am EDT Monday for coastal Volusia-
northern Brevard-southern Brevard.

Am...Small Craft Advisory until 8 am EDT Monday for Flagler Beach to
Volusia-Brevard County line 0-20 nm-Flagler Beach to
Volusia-Brevard County line 20-60 nm-Sebastian Inlet to
Jupiter Inlet 0-20 nm-Sebastian Inlet to Jupiter Inlet 20-
60 nm-Volusia-Brevard County line to Sebastian Inlet 0-20
nm-Volusia-Brevard County line to Sebastian Inlet 20-60 nm.


National Weather Service Glossary of Abbreviations