Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Melbourne Florida
107 PM EST Thursday Dec 5 2013
Tonight-Friday...the convergence line that developed earlier this
morning off the Bahamas has remained stubbornly persistent into this
afternoon...continuing to produce light to occasionally moderate
showers across Palm Beach County into Martin and southern St Lucie.
Given its persistence...and satellite presentation...will keep the
mention of light showers in this area through this evening and
Otherwise...there will be little change in the larger synoptic
pattern over the next 24 hours as the peninsula remains along the
axis of the western Atlantic ridge and the 591-592dm upper level
ridge center transits the state. These features will continue to
block the progression of the Arctic front moving through the Midwest
and deep south...keeping east central Florida warm and mostly dry.
With only minimal changes to the airmass and the areal extent of fog
coverage over the past two mornings...will cut back the mention of
fog in the forecast to the I-4 corridor and points northwest. Patchy
ground/field fog will be possible elsewhere.
Overnight lows from the low 60s interior to middle-upper 60s
Brevard/Treasure Coast. Highs on Friday continue 5-10 degrees above
normal in the middle 80s interior and low 80s coast.
Friday night/Sunday...surface ridge shifts east into the western Atlantic while
middle and upper ridge hangs in over Florida with a slight weakening late in
the period. Low level flow will continue out of the S to southeast with above
normal temperatures continuing. Frontal boundary will remain locked well north
of forecast area...however as upper ridge breaks down upper SW flow will
increase high and then middle level moisture with clouds diffusing
sunshine. During overnight period will restrict patchy late night
fog to areas north-west of I-4.
Mon-Wed...trough axis aloft will move through The Rockies and into
the Midwest which will shift ridge across Florida farther east. The
00z runs of the GFS and European model (ecmwf) are now in much better agreement
showing cold front moving into central Florida by late Tuesday
after/evening and pushing gradually southward across the area through
Wednesday. Best chance for rain will be along and behind this
boundary into Tuesday night and Wednesday due to weak overrunning
moisture in the lower levels. However at this time it is not looking
like we will receive much precipitation with this scenario. Have
increased probability of precipitation slightly up to 30 percent late in the forecast period
due to better model agreement with frontal passage.
Warmer than normal conditions will continue into early next week
with highs in the low/middle 80s Monday and Tuesday. Then a slightly
cooler airmass and increased cloud cover behind the boundary will
bring maximum temperatures back to around normal on Wednesday.
Aviation...prevailing VFR. Fog development kism-kdab after 06/06z
with prevailing MVFR visibilities and tempo IFR conditions. Local MVFR fog
development elsewhere. Isolated -shra producing tempo ceilings fl020-030
south of kfpr-Kobe with onshore moving convergence band.
tonight-Friday...no change in the synoptic pattern in place as high
pressure ridge continues to reside over the adjacent
Atlantic...leading to favorable boating conditions. Ridge axis
directly across the Central Peninsula will keep winds
south-southwest 5-10kts north of Sebastian Inlet and east-southeast
10-15kts areas south. Seas 2-3ft with dominant periods 10-11sec.
Saturday-Sunday...as ridge breaks down south to southeast winds of
10 to 15 knots will occur across all coastal waters. Frontal bounday
will remain north of the area through the weekend.
Preliminary point temps/pops...
dab 61 82 63 81 / 10 0 10 10
mco 60 84 63 83 / 10 0 10 10
mlb 66 81 66 81 / 10 0 10 10
vrb 70 81 65 81 / 10 0 10 0
Lee 60 83 63 83 / 10 0 10 10
sfb 64 84 64 83 / 10 0 10 10
orl 63 84 64 82 / 10 0 10 10
fpr 69 81 64 81 / 10 0 10 0