Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Melbourne Florida
202 PM EST Monday Dec 9 2013
current-tonight...the low-level ridge axis is forecast to remain
across the Central Peninsula through tonight...though light winds
will veer to south/south-southwest by sunrise Tuesday morning. The
frontal boundary that has been hung up north and west of the area
will settle into the Florida Panhandle late overnight. Wind speeds
above the surface may be too strong for any widespread fog
development overnight...though will retain patchy fog wording in
grids/zones for areas near and north of the I-4 corridor. Will keep
conditions dry. Overnight lows continue mild and in the 60s.
Tuesday...a rather strong upper jet will give the front the necessary
incentive to push southward from the Florida Panhandle into the
north-Central Peninsula during the day. The ridge axis will retreat
south and eastward. Winds will respond by veering to southwest
during the morning and west-southwest by late in the day near and
north of the I-4 corridor. Further southward winds look to remain
south or south-southwest. We may see development of the East Coast
sea breeze in the afternoon which would back winds along the
Treasure Coast to east-southeast. Wind speeds will average 7-12 miles per hour.
Deep layer moisture will be slow to increase and the airmass will
need time to modify. For this reason will only carry a 20 percent
chance of probability of precipitation in the afternoon for north of the I-4 corridor. Probability of precipitation
around 10 percent south of here. Aside from the jet energy to the
north middle level dynamic support will remain rather weak. Forecast
highs in the lower to middle 80s ahead of the approaching front.
Wednesday...(modified previous disc) latest guidance suggest the approaching front will
stall over so central Florida and act as a pool for low level moisture
while suppressing the Atlantic high pressure ridge across southern most Florida.
Precipitation chances will best be ascd with the stalled boundary roughly
across the Treasure Coast and lower chances for points northward.
This setup could favor measurable rain for a couple forecast
periods in vicinity of the stalled feature...but potential for any strong
or organized convection will remain low.
Deepening onshore flow Wednesday will push maximum temperatures back to within 5f degree
of climatology average...still above average with readings in the M/u70s along and north
of I-4... u70s/l80s space and Treasure coasts. Light north/NE flow Wednesday
night will keep min temperatures in the l/m60s interior...M/u60s along the
progressive weather pattern through the latter half of the week as the
jet pattern across the Continental U.S. Becomes largely zonal in nature. The Post
frontal ridge over the eastern Continental U.S. On Wednesday will be reinforced by a
polar ridge by daybreak Thursday. Embedded within a strong zonal wind
component...this new ridge will then push off the middle Atlantic coast by
week's end where it will gradually weaken. This will allow surface/low
level winds across central Florida to back to the north/NE and freshen on
Thursday...keeping seasonable maximum/min temperatures in place. Lingering precipitation
into Thursday morning mainly S of the I-4 corridor before the cooler and
more stable air works its way into the County Warning Area.
as the polar ridge builds into the west Atlantic...winds will veer to the
S/southeast on Sat...then to the west/SW Sat night. This will allow temperatures to
warm back above climatology ahead through most of the weekend. GFS and European model (ecmwf)
indicating significant differences with respect to the next frontal system over
the weekend: European model (ecmwf) has a more amplified middle level short wave over the
Southern Plains and takes its parent low across the lower MS valley by
daybreak Sat...while GFS is less amplified in the middle levels and
carries the core of its system across the Great Lakes. Not
surprisingly...European model (ecmwf) extended MOS has a wetter and cooler solution
than GFS...probability of precipitation 15-20pct points higher and Post frontal maximum temperatures
around 10f cooler. Will split the difference for now as there is ample
time for subsequent model runs to hammer out a better consensus.
VFR conditions expected. Deep southerly flow may be too strong
for widespread fog formation...but still expect some patchy fog
near and north of the I-4 corridor late overnight into early Tuesday
morning. Southeast/south winds will fall to below 5 kts. A weak
frontal boundary to the north slides into north-central Florida late in
the day on Tuesday with winds veering to SW. A 20 percent chance or
less of precipitation will be possible Tuesday afternoon as the airmass
current-tonight...the low-level ridge axis remains firm in
place over the Central Peninsula overnight. South-southeast/S wind flow will
veer more south-southwest by daybreak Tuesday morning. Speeds will average between
10 and 15 kts over the open Atlantic. A long period swell will push
seas 3-4 feet very near shore and 4-5 feet further away from the coast.
Will not rule out an isolated shower over the Gulf Stream waters.
Tuesday...the ridge axis weakens as a cold frontal boundary pushes into
the north-central Florida Peninsula by late in the day. Winds will
respond by veering south-southwest/SW during the day. An East Coast sea breeze
is possible along the Treasure Coast in the afternoon which may back
winds to east-southeast. Wind speeds below 15 kts and are forecast to fall
below 10 kts later in the afternoon. Seas 3-4 feet near shore and 4-5
Wednesday-Wednesday night...(previous) gentle to moderate north/NE breeze as the
surface ridge over the middle Atlantic by a polar ridge that will push out of
the Pacific northwest through midweek. Seas 3-4ft nearshore and 4-6ft offshore.
Thursday-Thursday night...winds will freshen out of the north after daybreak to
20-25kts and veer to the through sunset NE Thursday night as the polar ridge
moves across the appalachian and approaches the middle Atlantic coast. Seas
building to 5-7ft by afternoon...6-8ft nearshore and 8-10ft offshore
Friday-Friday night...fresh to strong NE breeze will weaken slowly as the
polar ridge pushes off the middle Atlantic coast and weakens over the west
Atlantic...but overall conditions will remain rough. Winds decreasing to
around 20kts through the day...then to 15-20kts overnight. Seas 6-8ft
nearshore and 8-10ft offshore through the day...decreasing to 4-6ft
nearshore and 6-8ft offshore overnight.
Preliminary point temps/pops...
dab 63 83 58 75 / 10 20 20 20
mco 63 84 59 79 / 10 10 20 20
mlb 67 83 64 80 / 10 10 20 30
vrb 66 83 64 80 / 10 10 20 30
Lee 64 83 55 78 / 10 20 10 20
sfb 64 84 59 78 / 10 10 20 20
orl 65 83 59 78 / 10 10 20 20
fpr 64 84 64 80 / 10 10 20 30