Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Melbourne Florida
340 PM EST Friday Dec 26 2014

Discussion...

Current...
clouds had filled in across all but a tiny sliver of Northern
Lake/Volusia counties as of 2pm. Local 88d/tdwr imagery showed a few
sprinkles occurring across the southern half County Warning Area. This put The Breaks on
the already limited diurnal temperature rise...and as a result just about
all areas topped out in the 70-75f range...with a few u60s north/west of
I-4.

Tonight...
forecast is a bit tricky...hinging on cloud cover and how well the
model guidance handles the ongoing shallow weak upglide event
causing it. For this evening...expect widespread overcast and
sprinkles to linger for several hours. Later tonight...local model
guidance subtly weakens and veers the 925-850mb flow...decreasing
the upglide. If this verifies correctly...we should see resultant
decrease clouds after midnight...which would allow for fog and some
stratus to develop. Am not at all confident in dense fog developing
as mav guidance has backed away from the low visibilities.
Consequently...because of the uncertainty...have broadbrushed all
areas with patchy fog...and will let subsequent shifts monitor the
evolution of the present SC deck. Mins will range from the u50s to
around 60f near and northwest of I-4...and 60-65f to the southeast.

Saturday...
a warmer day is on tap after any morning fog/low clouds that do
develop burn off. Probably more clouds than sun...but sufficient
diurnal heating to push temperatures into the u70s/l80s. Shaved about 1-2f
off of the mav numbers just in case mornings clouds are a bit more
widespread/persistent.

00z sun - 12z Monday...
a deep anticyclone centered over the Bahamas will drift into the west
Atlantic as a hi amplify short wave trough over the Rocky Mountains rides over its
northwest flank and flattens out over the northern plains/upper Midwest. As it
does...a secondary h100-h70 anticyclone centered over the Carolinas
will push in the west Atlantic...where the two will merge into one
late Sun night. The consolidated ridge will become a formidable
barrier that not only will block the advance of the next frontal
trough currently advancing toward the middle/lower MS valley...but will
deflect much of the jet energy over the eastern Continental U.S. Off to the north.

A low level moisture band associated with a stalled front over central Florida
will become entrained in the clockwise circulation pattern over the
region. However...the suppresive nature of the ridge pattern
coupled with its weak 850 mb-h30 vorticity/Omega lift and h30-h20
divergence will keep precipitation chances too low to mention. Primary weather
concern will be late night/early morning fog formation given the
anticipated light surface/boundary layer winds and nearly saturated h100-h90
layer. Prevailing srly flow will keep temperatures above climatology average...maximum temperatures
in the u70s/l80s (5-10f above avg)...min temperatures l/m60s interior and
M/u60s along the coast (arnd 15f above avg).

Mon-Thu...(prev disc)
middle level pattern flattens out into next week as the first
of several shortwaves moves across the eastern US on Monday. Next
rain chances arrive Monday night as surface front moves into Florida
with some differences between the GFS and European model (ecmwf) on how quickly the
front makes it through. The European model (ecmwf) with its stronger and lower
latitude surface low bring the front completely through central
Florida on Tuesday but with considerably less middle level moisture
than the slower and weaker GFS. A consensus of both puts a slight
chance of showers across the region Monday night-Wednesday by which even the
slower GFS has the front and deeper moisture into S Florida. Drier
day on Thursday as we will be under weak ridging ahead of the next
system developing over the western Gulf.

Highs in the middle-upper 70s with a few around 80 Monday and Tuesday. A
slight cooldown with the frontal boundary Wednesday and Thursday with highs
ranging from the low 70s across the north to upper 70s across
Okeechobee and the Treasure Coast.

&&

Aviation...
forecast is pretty much on target. VFR north of mlb-lake kism with
ceilings ranging from ovc035-050 as you head north. To the south...MVFR
ceilings trend ovc030-020 as you head south. Expect ceilings to drop through
MVFR range. After 08z...prevailing ceilings near bkn010 and 3-5sm br with
areas imc developing in fog/stratus. As stated above...a lot depends
on to what event the SC deck breaks up tonight.

&&

Marine...
tonight-Sat...gentle onshore winds around 10kt or a little less with
seas 2-3ft. Long period swell train (aoa 15sec pd) begins to arrive
into the outre water by late afternoon/early evening. This will
nudge combined seas well offshore up to 3-4ft toward sunset.

Sun-Sun-night...light to gentle srly breeze through the day...becoming
gentle to moderate S/SW overnight as a new frontal trough presses into
the deep S and interacts with the hi pressure ridge building over the west
Atlantic. A lingering Erly swell will produce combined seas between 3-4ft
nearshore and 4-5ft offshore.

Monday-Monday night...the frontal trough will press into the Florida Panhandle
through the day...then into the north peninsula overnight...weakening the
western flank of the west Atlantic ridge in the process but sacrificing some of
its own strength as well. Light to gentle S/SW breeze through the
day...becoming SW through midnight...then west/northwest in the predawn hours. Seas
2-3ft nearshore and 3-4ft offshore...subsiding to 2-3ft areawide after
sunset as winds veer to offshore.

Tuesday-Tuesday night...light to gentle west/northwest breeze becoming gentle to moderate
north/northwest by late afternoon as the frontal trough sags into the Central
Peninsula. Seas at or below 2ft...except 2-3ft in the Gulf Stream north of feet.
Pierce inlet.

Wednesday-Wednesday night...frontal trough will stall over the S half of the
peninsula...resulting in a prevailing light to gentle nearly breeze.
Seas 2-3ft through the day...building to 4-5ft offshore north of Cape
Canaveral as a nerly swell begins to impact the local Atlantic.

&&

Preliminary point temps/pops...
dab 58 75 65 79 / 0 10 10 10
mco 60 80 64 81 / 0 10 10 10
mlb 65 79 68 80 / 0 10 10 10
vrb 65 80 66 80 / 0 10 10 10
Lee 57 79 64 81 / 0 10 10 10
sfb 59 80 65 81 / 0 10 10 10
orl 60 80 65 81 / 0 10 10 10
fpr 65 79 67 80 / 0 10 10 10

&&

Mlb watches/warnings/advisories...
Florida...none.
Am...none.

&&

$$

Short term/aviation...cristaldi
long term/impact weather...bragaw

National Weather Service Glossary of Abbreviations