Area Forecast Discussion
Issued by NWS Melbourne, FL
FXUS62 KMLB 240810
Area Forecast Discussion
National Weather Service Melbourne FL
410 AM EDT SUN JUL 24 2016
Today-tonight...water vapor imagery depicts upper low aloft of
Treasure Coast at 08Z. Low will continue to move W/SW across
southern penisula today...setting up a tight moisture gradient
across central/south FL. Precipitable water values fall to near 1
inch across NE CWA today while pocket of near 2 inch PW transits
Lake Okeechobee region. Anomalous low PW event will be short-
lived, with moisture recovery beginning across N CWA by sunset.
Aligned POPs today from nil across coastal Volusia to 40
percent/scattered across Treasure Coast/Okeechobee and western
Lake County...with 20 percent/isolated in between. With mid-level
temps cooling 1-2 deg across south CWA and presence of mid-
upper/dry air...some strong downburst winds possible with any deep
convection. Storm motion will again be slow...generally toward the
west or northwest near 5 mph...with propagation along boundaries
dominating at times. Max temps at or a hair above climo, with
mins 2-4 deg above normal.
Mon-Mon Night...Disorganized area of low pressure embedded within
the wrn extension of the Bermuda Ridge will merge with a weak H100-
H70 trof over the NE GOMex by daybreak. As the FL peninsula gains
the ascending flank of the consolidated trof, the Bermuda Ridge will
reorganize and merge with a weak anticyclone over the Deep South/Mid
Atlc. This in turn will allow the mean H100-H70 flow to shift to the
S/SE and tap a relatively moist airmass just east of the Bahama Bank
and pull it into the FL peninsula.
Shra/tsras chances looking pretty decent compared to recent days.
Model soundings indicate PWAT values increasing to arnd 2.00"
areawide by 18Z as a respectable knuckle of H85-H50 vorticity works
its way acrs the peninsula in the wake of the trof. The 24/00Z GFS
MOS PoPs came in btwn 50-60pct, as high as they have been in over a
week. However, am hesitant to bite off completely as the moisture
distribution thru the column, as indicated by the model soundings,
is not concentrated in the low/mid lvls. Instead, it is more
uniformly distributed thru the column...particularly abv H50.
Indeed, RAP40 analysis indicates dew point depressions acrs the
Bahamas are largely AOA 5C thru both the H100-H70 and H85-H50 lyrs.
The dvlpg S/SE H100-H70 flow will favor the interior counties for
diurnal convection. However...given the issues with the deep lyr
moisture...Will opt to keep PoPs in the sct category. Highest
chances (50pct) over the interior from Osceola nwd...40pct
elsewhere. Onshore flow will keep max temps in the U80s/L90s...a few
M90s over the interior. Mins L/M70s.
Tue-Sat...The inverted trof will dampen out by daybreak Tue...
leaving the Bermuda Ridge as the dominant WX feature for central FL
thru the remainder of the week. Upstream analysis of the upr lvl
winds show an 80KT lifting jet over the Nrn Plains, an 80KT zonal
jet over BC, and an 80-100KT zonal jet over the Aleutians. None of
these will be in position or will have the energy necessary to
induce the type of hi amp short wave trof capable of dislodging the
Bermuda Ridge. Furthermore, tropical Atlc analysis shows the closest
t-wave btwn 40-45W, too far away to impact the Ridge until the tail
end of the fcst at earliest.
Position of the axis will meander acrs the FL peninsula, as it is
wont to do this time of year. Light but steady S/SErly flow will
prevail thru the H100-H70 lyr, a direction that favors the interior
counties for highest PoPs. Even so...will keep precip chances aob
40pct as analysis of the tropical/subtropical Atlc shows a
surprising amount of dry air east of the Windward Passage assocd
with a large Saharan dust plume. No change in airmass...little
change in temps. Aftn maxes in the U80s/L90s along the coast...
L/M90s interior. Mrng mins in the L/M70s.
VFR KDAB as dry airmass should dominate. Farther south along
coast...sea breeze expected to initiate isolated/scattered
convection 17-19Z...perhaps lingering beyond 20Z across Treasure
Coast. Included period of VCSH at KTIX/KMLB, VCTS KMLB/KVRB and TS
KFPR/KSUA given expected proximity of sea breeze convection prior
to inland movement/propagation. For inland TAFs, included VCTS
17-21Z expect tempo TSRA at KLEE 19-22Z.
Today-tonight...Ridge axis north of CWA will promote 10 KT
easterly flow today enhanced by sea breeze circulation near shore
this afternoon. As high pressure begins to build east of the state
tonight...winds will veer more SE. Seas remain minimal...generally
2 ft or less near the immediate coast and up to 3 ft offshore.
Isolated/scattered showers...mainly south of Sebastian inlet where
deepest moisture resides.
Mon-Thu...Favorable boating conds for most of the upcoming week as
the Bermuda Ridge settles over the central north FL Peninsula. Light
to gentle S/SE breeze will prevail from Cape Canaveral southward...
S/SW to the north, bcmg E/SE near the coast each aftn with the
formation of the east coast sea breeze. Seas 2-3FT. Sct shras/tsras
.PRELIMINARY POINT TEMPS/POPS...
DAB 91 75 92 73 / 10 10 40 10
MCO 94 74 93 73 / 30 20 50 20
MLB 90 75 91 74 / 20 10 40 10
VRB 90 73 89 73 / 20 20 40 20
LEE 94 75 93 74 / 40 20 50 20
SFB 93 75 93 74 / 20 10 50 20
ORL 93 75 93 73 / 30 20 50 20
FPR 89 73 89 74 / 30 20 40 20