Area Forecast Discussion
Issued by NWS Melbourne, FL
FXUS62 KMLB 260024
Area Forecast Discussion
National Weather Service Melbourne FL
824 PM EDT WED MAY 25 2016
Mostly clear skies expected overnight as high pressure off of the
southeast U.S. coast generates a E/NE flow that will continue to
usher in drier air across the region. Onshore flow should remain
elevated enough to keep lows in the low 70s over much of the
Brevard and Treasure Coast tonight, while farther north and inland
min temps in the mid to upper 60s are expected. No updates needed
as forecast looks on track.
.AVIATION...VFR conds expected next 24 hours.
.MARINE...High pressure offshore of the southeast U.S. coast will
continue a gentle to moderate E/NE breeze over the waters, around
10-15 knots. Seas will reside around 3-4 feet.
.Previous Discussion... /issued 350 PM EDT WED MAY 25 2016/
Atlc hi pres ridge will persist over the Deep South thru late week
as a negative PNA pattern dominates the ConUS WX pattern. Deep
onshore flow will persist over the subtropical Atlc...pushing an
erly wave that currently extends from Hispaniola to Bermuda acrs the
Bahama bank. As the wave axis approaches...the dry/stable airmass
overhead will slowly erode...allowing precip to gradually re-enter
the fcst. Moisture advection will be limited to AOB 10kft...
however...as the ridge maintains a strong subsidence inversion thru
the H85-H70 lyr...PWAT values expected to increase to arnd 1.00" on
Thu then 1.00"-1.25" on Fri.
Position of the ridge axis will maintain a persistent E/NE breeze
thru the H100-H70 lyr will maintain the ongoing dry air advection
pattern thru Thu night. Will keep the fcst dry thru 12Z Fri and cap
PoPs in the 20/30pct range btwn 12Z Fri-12Z Sat. Furthermore...the
E/NE flow regime does not favor deep convection...will limit tsras
to the interior of Osceola/Okeechobee counties Fri aftn. Onshore
flow will keep aftn max temps near avg (M/U80s)...overnight mins a
few degs abv mins abv avg (U60s/L70s interior...L/M70s along the
Sfc high pressure from Bermuda to the SE US coast will weaken as the
southern extent of a stalled sfc trough east of the islands exhibits
some slow development as a wave. This feature is expected to drift
wwd toward the Bahamas and reach a point of closest approach to the
forecast area during the weekend as an inverted trough or perhaps a
broad sfc low north of the Bahamas.
Local rain chcs will hinge largely on whether or not discrete low
pressure develops...which would likely reduce rain chcs locally
should the feature pass to the east and north of the area as
expected. An open wave would keep a broader moisture field
regionally and rain chcs would be somewhat higher in this
scenario. The lcl forecast maintains a slow increase of rain chcs
late week and during the weekend (with chc wording during weekend)
until whichever scenario unfolds with the feature to the east.
ltst ECM/GFS guid suggests sufficient weakness wl exist to the north
of the SE coast feature...allowing for it to continue a trek away
from the area early next week. Sufficient moisture across the ECFL
area along with a rather weak pressure gradient should allow for wet
season boundary driven convection at least the early half of next
Sfc Winds: Thru 26/00Z...E/SE 11-14KTS with ocnl G18-22KTS. Btwn
26/00Z-26/03Z...E/NE dcrsg to 3-7KTS interior sites...6-9KTS coastal
sites. Btwn 26/13Z-26/15Z...E/NE incrsg to 9-13KTS.
Vsbys/WX/Cigs: VFR all sites.
Tonight...Hi pres ridge centered over the nrn Gulf Coast/FL
Panhandle will generate a gentle to moderate E/NE breeze over the
lcl Atlc. Seas 3-4ft...largely in an Erly swell.
Thu-Fri...Little overall change as the ridge axis remains anchored
over the Deep South/Mid Atlc...maintaining a gentle to moderate E/NE
breeze. Pgrad may tighten by late Fri aftn as an easterly wave
extending from Hispaniola to Bermuda works its way into the Bahama
Bank...offshore winds bcmg a moderate to fresh E/NE breeze. Seas 3-
4ft thru midday Thu...building to 4-5ft offshore by sunset Thu...
then areawide by midday Fri as the persistent onshore flow begins to
push additional swell into the FL Atlc coast. Seas up to 6ft in the
Gulf Stream Fri aftn/evng. Isold shras/tsras mvg onshore Thu night
into Fri...bcmg sct Fri night.
Sat-Mon...Fcst will hinge largely on how the easterly wave dvlps and
tracks. Models in good agreement...bringing a weak closed sfc low
into the GA/SC coast Sat night into Sun. Resulting sfc/bndry lyr
winds backing to the N/NW by daybreak Sat...though a weak pgrad on
the system`s srn flank would allow the east coast sea breeze to dvlp
each aftn...forcing winds to shift back to the E/NE near the coast.
Early Sat...seas 3-5ft N of Cape Canaveral and 2-4ft S of the
Cape...subsiding to 3-4ft and 2-3ft respectively by sunset Sat...
contg into early next week. Chc shras/slgt chc tsras.