Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Melbourne Florida
8 PM EDT Wednesday Mar 12 2014
Current...showers associated with the weakening surface trough just
about out of east central Florida. Radar detecting returns moving in
from the brisk westerly flow off the Gulf of Mexico. If there are
showers they would be more of the speed convergence type given the
west to east orientation of the clouds and showers and that the
forward speed of the air would be slowing down a little as it moves
After the evening showers over the southern counties move into the
Atlantic the weather should be over for the night. Cool air
advection will keep northwest to north winds in the 10 to 15 miles per hour
range with occasional gusts to 20 to 25 miles per hour the first half of the
night then the winds should diminish to around 10 miles per hour.
The winds should have diminished enough to allow the lake Wind
Advisory at 8pm/00z
Previous zones discussion
Current...waning pre-frontal convection in a loosely organized band
along surface trough extending from the Atlantic across Florida from mlb-srq and
into the Gomex. Intensity trend has been downward since late morning
with no indication of any lightning over land since middle morning. Thus...it
appears as though the increasingly less favorable synoptic factors
mentioned in the morning afd are winning out. Plan to remove mention
of ts with the afternoon zone forecast product...but will use pre-first period to acct
for higher probability of precipitation before sunset. Precipitation has become quite sparse north
of the surface trough with temperatures having fallen back into the M-u70s.
Will keep just a slight chance for showers north through 00z/8pm...
but expect any activity to collapse by sunset if not a bit earlier.
Current wind speed/gusts easily support keeping lake wind advection up
through 800 PM.
Tonight-Thu...precipitation will end across the far southern cos a little
past sunset...so will have just a small lingering shower chance
there early this evening. The strong cold front will reach Northern
Lake/Volusia counties by 06z/2am and sweep rapidly southeastward through the
County Warning Area prior to sunrise. Clearing with strong cold air advection will ensue behind the
front late tonight and throughout Thursday. Wide range of mins forecast
with u40s across the far north...l60s over the far southeast...and 50s in
between the two extremes. Full sun but much cooler Thursday with m60s for
lake/Volusia and coastal Brevard cos...u60s elsewhere (near 70s in
Thursday night-Friday night...rather benign weather pattern with zonal flow
aloft and surface high pressure initially over the Gulf Coast
sliding eastward into the western Atlantic by the end of the period.
Conditions will remain dry. Winds becoming light each night with a
moderate onshore (east/east-southeast) flow for Friday. Overnight lows
mostly in the 40s Thursday night with a few lower 50s along the immediate
St. Lucie/Martin coasts and including the barrier islands. Fri's
highs mainly in the lower 70s. Friday night lows a bit more mild thanks
to the ocean modified air and in the 50s areawide.
Previous extended forecast discussion...
Sat-Tue...zonal jet pattern across the southern tier states will gradually
transition to a lifting orientation over the weekend in advance of
the next frontal trough. With ridging over the west Atlantic already in
place...the stage will be set for another slow moving frontal boundary
through central Florida that will require an extended period of precipitation in the
forecast into early next week.
As the front stalls over the Panhandle and winds veer to the S/SW...
a warm air advection pattern will develop that will push temperatures into the
u70s/l80s on Sat...then into the l/m80s areawide on sun. As the
front slides into the Northern Peninsula...clouds and periodic rain showers will
keep maximum temperatures in the M/u70s...while prefrontal temperatures over the southern
County Warning Area remain in the l/m80s. Min temperatures generally in the u50s/l60s...
except l/m60s along the Treasure Coast
While this particular weather pattern usually does not generate large
outbreaks of strong/severe weather...cannot rule thunderstorms and rain showers out completely especially
across the southern County Warning Area where temperatures will warm into the l/m80s during the
heat of the day. Will go with a mix of rain showers/thunderstorms and rain showers through the period...
capping probability of precipitation around 40pct Sun night into Tuesday.
Aviation...VFR with west to northwest winds around 15 knots with
occasional gusts to 25 knots most of the night.
Previous aviation discussion
Potential for brief IFR visibilities or ceilings in convective rain showers
is rapidly lessening south of mlb-srq. And nothing worse than spotty
MVFR conds in scattered rain showers shifting south across the vrb-sua corridor...
ending by about 02z. VFR/sky clear spreading southward after 06z behind cold
frontal passage and lasting through Thursday with nearly wind gusts 20-23kt.
current-overnight...buoy 009 was recording westerly winds around 15
knots and seas around 3 feet which would suggest that the cool air
advection had not yet reached the buoy. Expecting winds speeds to
increase to 20 knots and shift to the northwest as high pressure
builds in from the northwest during the evening. A Small Craft
Advisory is in place for the offshore waters and expands to the
nearshore waters by midnight.
Previous marine discussion
Gusty SW to wrly winds will continue through late evening
ahead of cold front. Northwest-north-northwest wind surge will spread rapidly southward
behind the front...with seas rapidly building to 6-9ft...and perhaps
a bit higher in the Gulf Stream on Thursday. Small Craft Advisory continues late tonight
with a cautionary statement for all zones in the interim.
Thursday night...high pressure in control along the Gulf Coast and
southeast U.S. North-northwest/north initial winds veering to north-northeast/NE by daybreak Friday
morning. Wind speeds around 20 kts offshore and around 15 kts near
shore decreasing overnight to around 15 kts offshore and 10-15 kts
near shore by daybreak Friday morning. Small Craft Advisory/scec likely across many of
the zones to start this period as boating conditions for small craft
remain hazardous still...though slowly improving. Seas 4-5 feet near
shore and 5-7 offshore/Gulf Stream lowering about a foot by the end
of this period.
Friday-Friday night...high pressure will slide off of the southeast U.S.
Coast and into the western Atlantic. NE/east winds veering to east-southeast/southeast by the
end of this period. Wind speeds continue to decrease a bit and
mainly at or below 15 kts. Seas to 3-5 feet nearshore and 4-6 feet offshore/Gulf
Stream subsiding to 2-4 feet near shore and 3-4 feet offshore Friday night.
Sat-Mon...previous...Atlc hi pressure ridge will be the dominant weather
feature through the upcoming weekend as a new cold front pushes into
the deep south and stalls over the Florida Panhandle. Interaction between
these two systems will generate a gentle to moderate S/southeasterly breeze
with seas 2-4ft on Sat subsiding to 2-3ft sun. Chance rain showers on sun north of
Sebastian Inlet late in the day...slight chance S of the inlet.
Previous fire weather discussion
Thursday...were it not for erc values being marginal...we would be
running with a rfw for most of the area Thursday as winds and widespread
min relative humidity values below 35 percent will be supportive. In spite of
that...weather conditions will promote rapid spread of any new
Friday...high pressure slides off of the southeast U.S. Coast with
veering winds to the east across east central Florida. This will
begin to modify the airmass with furthest interior reaches still
finding a few hours of low relative humidity between 30-35 percent.
Preliminary point temps/pops...
dab 48 64 44 71 / 10 0 0 0
mco 53 67 45 75 / 10 0 0 0
mlb 56 65 49 73 / 10 0 0 0
vrb 59 67 50 73 / 20 0 0 0
Lee 48 65 42 75 / 10 0 0 0
sfb 52 66 45 74 / 10 0 0 0
orl 53 66 47 75 / 10 0 0 0
fpr 61 67 49 73 / 20 0 0 0
Florida...Lake Wind Advisory until 8 PM EDT this evening for coastal
Volusia-Indian River-inland Volusia-Martin-northern Brevard-
Brevard-Southern Lake-St. Lucie.
Am...Small Craft Advisory from 11 PM this evening to 10 PM EDT
Thursday for coastal waters from Flagler Beach to Volusia
Brevard County line out 20 nm-coastal waters from
Sebastian Inlet to Jupiter Inlet out 20 nm-coastal waters
from Volusia Brevard County line to Sebastian Inlet out 20 nm.
Small Craft Advisory from 8 PM this evening to 4 am EDT Friday
for waters from Flagler Beach to Volusia Brevard County
line 20 to 60 nm offshore-waters from Sebastian Inlet to
Jupiter Inlet 20 to 60 nm offshore-waters from Volusia
Brevard County line to Sebastian Inlet 20 to 60 nm offshore.
long term/impact weather...pendergrast