Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Melbourne Florida
440 am EDT Thursday Apr 17 2014
..wet through Saturday with potential for locally heavy rainfall
especially along the coast...
..hazardous boating conditions through this weekend and into early
Today-tonight...Post frontal dry airmass remain fairly pervasive
across the region...especially across the interior and Volusia
County where dewpoints are still in the middle-upper 50s.
Models have so far been very gung Ho in lifting the old frontal
boundary/enhanced moisture back north...but it appears that the
northward trend may be starting as one heavy rainband set up earlier
this evening across Broward County that has since dissipated.
Current analysis shows a band of enhanced low level moisture from
Brevard/Osceola counties southwards coincident with an area of wind
convergence in the 1000-850mb layer. This is where radar is also now
picking up on a recent upswing in shower coverage.
Local WRF model shows a band of enhanced precipitation around daybreak over
the Treasure Coast...but hrrr model keeps this activity more over
South Florida until later. Its tough to say where or if any locally
heavy bands may set up until they do...but just ahead of/along warm
front would be the best bet. Do expect an increase in shower
frequency towards daybreak across the Treasure Coast.
Frontal remnants and best isentropic lift will move back to the
north across central Florida through the day...accelerating into
North Florida tonight as upper level shortwave swings eastwards and
surface low develops across the Gulf. Have tapered back rain chances
to 20 percent northern interior to 60 percent Okeechobee/Treasure
Coast based on current trends/model forecast. Could see a few
periods of heavy rain along the coast today...before the best rain
chances will lift north of the region later tonight.
Though it will be breezy again this afternoon...it doesn't appear
that speeds/gusts will be quite as high as yesterday so have not
issued a lake Wind Advisory. However conditions will still remain
choppy on area lakes.
Coastal highs will be highly dependent on cloud cover and precipitation
timing...but overall expected anywhere from low 70s along Volusia
coast to upper 70s/around 80 in Brevard/Treasure Coast. Interior
temperatures in the upper 70s and low 80s. Mild overnight as flow becomes
more east-southeast with lows in the upper 60s interior/around 70s
Fri-sun...the overall trend of the short range forecast is decidedly
slower and wetter into Sunday. Strong southern stream short wave
trough will move east along the eastern Gulf Coast before pinching off
into a closed middle-upper low in vicinity of the Florida/al/GA tri-state region Friday
night. The closed low will then drift slowly east somewhere between the
Florida/Georgia border and peninsular North Florida on Sat...easing offshore Sat
night and drifting farther offshore and away from the Florida East Coast
At the surface...available model guidance has converged toward a more
agreeable (slower) solution...although the GFS continues to be the
fastest. Surface frontal wave spins up into a low and tracks across the
northestern Gomex Friday...with the surface and middle/upper level lows becoming
vertically stacked by Friday night over North Florida. Surface warm front lifts
northward through central Florida during the morning...which should take
widespread stratiform rainfall northward across north FL/GA...while ecfl
breaks out into the warm sector of the Gomex low. Deep layer S-SW
flow with precipitable waters around 1.75" will lead to widespread showers/storms
with the potential for a band of stronger storms to reach ctrl Florida
from the Gomex (n/west of I-4) around sunset (give or take) and
continue to drop southeastward through the evening hours.
Surface low will be very slow to move across the state Friday night...and
then linger offshore the Florida East Coast throughout Sat. Sufficient
wrap around moisture will exist for scattered to numerous showers...and even
some storms given the cold h50 temperatures underneath the h50 low ovhd.
Expect lingering showers Sat night/Sunday in cool/moist nearly flow
on back side of the low...which will be grudgingly slow to put space
between itself and Florida. Coverage/intensity should be rather low.
Mon-Wed...weak high pressure finally settles in toward Florida early next
week...and drying conds out. There are some suggestions of a weak
frontal trough and ascd moisture band taking a glancing shot at North
Florida Tuesday-night into Wednesday...but will not get too involved in dissecting
day 6-7 probability of precipitation given the more sig weather in days 1-3.
Aviation...moist and cloudy through the period...though overall it
appears most locations will remain just inside VFR with prevailing
ceilings fl035-050. Coastal sites will be more likely to see MVFR ceilings
fl020-030. Isolated rain showers moving onshore into areas south of kvrb
through 13z...then becoming sct-nmrs. Coverage will increase from
south-north as old frontal boundary lifts back to the north through
the day. A few heavier rain showers may produce tempo IFR conditions mainly
along coastal sites. Could see prevailing IFR ceilings later tonight as
warm front lifts north of region.
Marine...today-tonight...gusty northeast to east flow will continue
to produce hazardous conditions for small craft. Pressure gradient
will remain strongest over waters north of Sebastian Inlet...keeping
winds in the 20-25kt range into this evening. Warm front lifting
back to the north will ease gradient further south...veering winds
more east in the 15-20kt range by late morning off the Treasure
Coast. Winds will veer east-southeast and drop to 15-20kts over all
the waters by late tonight as the warm front lifts north of the
Will keep advisory for winds/seas north of Sebastian Inlet through
late tonight with seas 5-7ft nearshore/6-9ft offshore. Will have
advisory for seas south of Sebastian Inlet where winds will be
lighter...but seas will be similar to northern sections due to
initial northeasterly trajectory.
Fri-Mon...a slight decrease in winds/seas is expected as the warm
front lifts northward through the area Friday. However...still looking at
cautionary conditions with 15-20kt and seas to 6ft...possibly a bit
higher. Coverage of rain and storms/gusty winds will remain marine
threats into Saturday. Synoptic gradient winds will begin to pick
back up Sat afternoon as the low center moves offshore the Florida East
Coast and pgrad tightens. Seas will ramp back up to 7-10ft or a
little higher Sat night through sun as west-northwest winds shift to north and north-northeast
behind the slowly departing low. Slow improvement in winds seas Monday.
Preliminary point temps/pops...
dab 73 68 78 64 / 20 50 80 60
mco 79 67 82 66 / 20 50 80 60
mlb 79 71 81 69 / 50 40 70 60
vrb 79 72 81 70 / 50 40 70 60
Lee 78 66 79 61 / 20 50 80 60
sfb 78 67 82 64 / 20 50 80 60
orl 79 68 82 65 / 20 50 80 60
fpr 80 70 82 72 / 60 40 70 60
Am...Small Craft Advisory until 6 am EDT Friday for coastal waters
from Flagler Beach to Volusia Brevard County line out 20 nm-
coastal waters from Volusia Brevard County line to Sebastian
Inlet out 20 nm-waters from Flagler Beach to Volusia Brevard
County line 20 to 60 nm offshore-waters from Volusia Brevard
County line to Sebastian Inlet 20 to 60 nm offshore.