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Area Forecast Discussion (AFD)

Issued by Melbourne, FL (MLB)

                            
000
FXUS62 KMLB 180822
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
420 AM EDT Sun Aug 18 2019

.DISCUSSION...

Current...Latest GOES-16 imagery shows a very tight moisture 
gradient setting up this morning with the Total Precipitable Water 
product showing 2.2" north of Orlando and 1.8" across St. Lucie and 
Martin counties. Even drier air is noted farther to the SE across 
Grand Bahama with values of 1.5-1.6".  Most recent RAP analysis 
depicts the surface ridge axis near or just slightly to the north of 
Lake Okeechobee. Scattered showers were again located along the 
western side of the peninsula.

Today-Tonight...Some showers and possibly a storm may move into the 
far interior this morning but believe most will stay dry. Through 
the rest of today, the surface ridge axis is forecast to move 
slightly northward, and as it does so the drier air will continue to 
advect northward into the area. This will limit coverage of showers 
and storms, especially south of Melbourne.  

Scattered showers and storms are expected to develop across the 
interior early this afternoon with scattered convection along the 
east coast sea breeze as well. The east coast breeze will initially 
form along the Treasure Coast but will be delayed by an hour or so 
for Brevard and Volusia county with some light opposing SSW/SW 
winds.   Even with the opposing flow the east coast breeze should 
make it decently far inland with the eventual meet up of the west 
coast breeze and associated convection across Volusia, Seminole, 
Orange, and Osceola counties. Highest PoPs (50%) are drawn across 
these counties where there is still sufficient moisture and where 
more boundary interactions will occur.  Elsewhere, have 40% N/W of I-
4, 40% Brevard, and 20-30% Okeechobee and the Treasure Coast 
counties where the driest air will be.  Some light SW steering flow 
may also push some of this convection back toward the Volusia coast 
late this afternoon into early this evening.  Convection will wane 
this evening, but some showers and storms may linger across the 
interior a couple hours after sunset. 

Max temps will reach the upper 80s to near 90 NW of I-4 with low 90s 
elsewhere.  Overnight lows tonight will be in the low-mid 70s once 
again. Current...Latest GOES-16 imagery shows a very tight moisture 
gradient setting up this morning with the Total Precipitable Water 
product showing 2.2" north of Orlando and 1.8" across St. Lucie and 
Martin counties. Even drier air is noted farther to the SE across 
Grand Bahama with values of 1.5-1.6".  Most recent RAP analysis 
depicts the surface ridge axis near or just slightly to the north of 
Lake Okeechobee. Scattered showers were again located along the 
western side of the peninsula.

Today-Tonight...Some showers and possibly a storm may move into the 
far interior this morning but believe most will stay dry. Through 
the rest of today, the surface ridge axis is forecast to move 
slightly northward, and as it does so the drier air will continue to 
advect northward into the area. This will limit coverage of showers 
and storms, especially south of Melbourne.  

Scattered showers and storms are expected to develop across the 
interior early this afternoon with scattered convection along the 
east coast sea breeze as well. The east coast breeze will initially 
form along the Treasure Coast but will be delayed by an hour or so 
for Brevard and Volusia county with some light opposing SSW/SW 
winds.   Even with the opposing flow the east coast breeze should 
make it decently far inland with the eventual meet up of the west 
coast breeze and associated convection across Volusia, Seminole, 
Orange, and Osceola counties. Highest PoPs (50%) are drawn across 
these counties where there is still sufficient moisture and where 
more boundary interactions will occur.  Elsewhere, have 40% N/W of I-
4, 40% Brevard, and 20-30% Okeechobee and the Treasure Coast 
counties where the driest air will be.  Some light SW steering flow 
may also push some of this convection back toward the Volusia coast 
late this afternoon into early this evening.  Convection will wane 
this evening, but some showers and storms may linger across the 
interior a couple hours after sunset. 

Max temps will reach the upper 80s to near 90 NW of I-4 with low 90s 
elsewhere.  Overnight lows tonight will be in the low-mid 70s once 
again.

Monday-Thursday...Approaching low-mid level inverted trough will 
erode the western flank of the Atlantic ridge starting late Mon, 
leaving the local area in a rather amorphous H50 pattern aloft 
through mid week, with the ridge trying to nose back westward into 
south Florida by Thursday. A very weak surface reflection of the 
trough will mark the leading edge of higher PWAT air, which 
overspreads the area from SE to NW starting Mon night. This erodes 
the narrow/transient tongue of drier air that will have pushed into 
the region ahead of it. POPS quickly ramp back up from (an almost 
unheard of since late July) 20-30 Monday to 60 areawide Tue, then 
back down to a 40 coastal/50 inland  split (60 for Lake Co.) Wed-Thu 
as onshore flow become established over the region. Max temps look 
close to normal, with coastal mins slightly above.

Friday-Sunday...Broad mid level troughing is progged to redevelop 
over the eastern CONUS, keeping the western flank of the Atlantic 
ridge suppressed a little to the south of central Florida into next
weekend. Not surprisingly, the low level reflection of the ridge, 
which starts off across the northern CWA Fri morning, sags south to 
about the latitude of Melbourne-Tampa Saturday, and near Lake Okee
by Sunday. Resultant veering of wind to S and SW will be accompanied 
by a slight increase in mean moisture and POPs. For now, the forecast 
shows a conservative increase from 40 to 50 percent, given this is 
out at the day 7-8 time frame. Temps look fairly close to late 
August normals.

&&

.AVIATION...
Some drier air working into the area is expected to limit coverage 
of convection today, especially south of MLB.  A few showers may 
approach the interior terminals mid-late morning, before scattered 
storms develop this afternoon.  Only carrying VCTS most sites with 
coverage not high enough for TEMPO inclusion.  For FPR-SUA, no 
mention of precip in TAF with chances too low across these sites. 
Convection will wane in the evening with possibly some lingering 
showers/storms near MCO/ISM an hour or so after sunset.

&&

.MARINE...
Today-tonight...Surface ridge axis near/slightly north of Lake 
Okeechobee will lift slightly north today to be near Cape Canaveral 
by this evening. Winds will be SSE 5-10 kt south of Sebastian Inlet 
this morning, and SSW 5-10 kt to the north.  Winds will veer to 
southeast at around 10 kt this afternoon as the sea breeze develops. 
For tonight, winds become more light and variable north of Cape 
Canaveral but will be from the SE to the south.  Wave model guidance 
continues to run too high so will continue 1-2 ft in the nearshore 
waters and 2 ft offshore.

Monday-Thursday...The appears to be no appreciable tightening of the 
local pgrad or increase in winds with the approach and passage of 
the weak inverted trough. Flow pattern for much of the upcoming week 
will be a gentle to moderate SE breeze with seas 2-3FT. Coverage of 
marine showers/storms looks to be highest form Monday night through 
Tuesday night.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  91  72  90  75 /  40  30  40  10 
MCO  92  74  93  75 /  50  30  30  10 
MLB  92  75  88  77 /  40  30  20  20 
VRB  91  74  90  77 /  20  30  20  30 
LEE  88  75  92  75 /  40  20  40  20 
SFB  92  74  93  75 /  50  30  30  10 
ORL  93  75  92  75 /  50  30  30  10 
FPR  92  73  90  77 /  20  20  20  30 

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&

$$

SHORT TERM/AVIATION...Combs
LONG TERM....Cristaldi