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Area Forecast Discussion (AFD)

Issued by Melbourne, FL (MLB)

FXUS62 KMLB 141931

Area Forecast Discussion
National Weather Service Melbourne FL
230 PM EST Mon Jan 14 2019


...Cool and Dry Weather through Mid Week...
...Increasing Rain Chances Late This Weekend Ahead of a Strong Cold 

Tonight...Deepening low pressure will move northeast away from the 
mid Atlantic coast as high pressure builds eastward from the Lwr MS 
Valley. Northerly low level flow will continue to advect chilly air 
into east central FL overnight. Lows will range from the lower to 
mid 40s across the nrn sections and the interior to the upper 40s to 
lower 50s along the immediate Treasure Coast and Martin county. Main 
forecast challenge will be amount of cloud cover across nrn sections 
with short range guidance indicating some stratocu moving into 
Volusia county overnight from the N/NE. Will trend skies mostly 
clear across the south of partly cloudy north. 

Tuesday...Surface high pressure will build toward MS with northerly 
flow in the morning becoming NNE along the coast into the afternoon. 
Should see some stratocu across the north in the morning then 
becoming sunny/mostly sunny all areas into the afternoon. Highs will 
be cool ranging from the lower to mid 60s nrn zones to mid to upper 
60s across the south. 

Wed-Thu...Srn branch of the H30-H20 jet stream has a dominant zonal 
component acrs the SE CONUS that will push a strong high pres ridge 
acrs the GOMex/Deep South and into the W Atlc thru mid week. GFS and 
ECMWF models in close agreement with this solution, which will 
result in a very strong H90-H70 subsidence inversion dominating the 
lcl airmass...PWat values generally btwn 0.50"-0.75". Fcst will be 

Motion of the ridge axis will maintain a N/NW flow thru the H100-H85 
lyr on Wed...resulting in seasonably cool temps with aftn maxes in 
the M/U60s...mrng mins in the L/M40s interior and M/U40s along the 
coast. Winds veering to a light E/NE flow on Thu as the ridge axis 
approaches the eastern seaboard. The dvlpg onshore flow will allow 
the cool airmass to modify...max temps in the U60/L70s... mins in 
the U40s/L50s interior and L/M50s along the immediate coast. 

Friday-Monday (modified previous)...Forecast in the long term 
remains right on track and is largely unchanged with no rain chances 
until Saturday night. Zonal flow aloft over the southeastern U.S. 
transitions to southwesterly as a large digging trough moves across 
the center CONUS.  While the op-models remain in their respective 
camps regarding the passage of this amplified short wave trough and 
strong cold front this weekend (the ECM/CMC are slower, GFS faster), 
their differences have narrowed even more than the 00Z model suite. 
Today's 12Z GFS is slightly slower (closer with the ECM/CMC) than 
the 06Z and 00Z GFS runs while the 12Z ECM is slightly faster than 
its 00Z run. The consensus remains for the FROPA to occur sometime 
Sunday, and with the closer timing agreement of the models, rain 
chances have been nudged upward. Highest POPs are now focused on 
Sunday-Sunday evening (60% Lake Kissimmee-Cape northward, 50% 
south), with low rain chances across the north-central for late 
Saturday night.

In addition, the spread for high temps on Sunday, which was as much 
as 15-20F across the north and 5-10F over the south has narrowed to 
about 5-10F areawide. Saturday will remain warm with U70s-80F maxes 
and mins U50s-L60s. Forecast temps have been lowered some for Sunday 
but remain on the high side of the consensus, since the GFS guidance 
has trended slower/warmer to a greater extent than the ECM has sped 
up/cooled. Much colder temps for Sunday night through Monday night.


Stratocu deck has been eroding with lingering SCT-BKN030 from KLEE-
KDAB early this afternoon. Should see VFR conds most terminals thru 
Tue morning, but CHC for sct-bkn stratocu deck (020-030) to linger 
KDAB and KLEE areas into the overnight. 


Tonight...Northerly winds to 10-15 knots nearshore and 15 knots 
offshore will keep seas elevated across the offshore waters and gulf 
stream up to 4-5 ft.

Tue...Northerly flow continues to 15 knots offshore with seas 3-4 ft 
near shore and around 5 ft offshore building to 6 ft across the 
portions of the offshore gulf stream waters in the afternoon. This 
will cause poor conditions for small craft operation, espec offshore.

Wed-Thu...Improving boating conds thru mid week as high pres builds 
acrs the GOMex/Deep South and into the W Atlc. Gentle to moderate 
N/NW breeze on Wed, diminishing to a light to gentle N/NE breeze Wed 
night, then a light E/NE breeze on Thu. Combined seas will remain 
enhanced by a diminishing long pd NErly swell...4-6FT areawide on 
Wed, subsiding to 3-5FT Wed night, then 2-4FT by late Thu aftn. 

Friday-Saturday...Favorable conditions for Friday and early Saturday 
with high pressure over head.  Light winds expected 5-10 kt with 
seas 1-2 ft nearshore and 2-3 ft offshore. Winds will increase and 
veer southeasterly to southerly by Saturday afternoon as high 
pressure slides eastward. Speeds will be 10-15 kt nearshore and 
around 15 kt in the offshore waters. Seas will remain 2-3 ft.


Northerly winds and a dry airmass will allow Min RHs to drop to 35 
to 45 percent across portions of the interior each afternoon though 
mid week. Winds will remain below 15 mph.


DAB  43  62  46  63 /   0   0   0   0 
MCO  45  66  44  68 /   0   0   0   0 
MLB  46  65  48  67 /   0   0   0   0 
VRB  47  67  50  68 /   0   0   0   0 
LEE  46  65  43  66 /   0   0   0   0 
SFB  44  64  43  68 /   0   0   0   0 
ORL  47  66  43  68 /   0   0   0   0 
FPR  47  67  50  69 /   0   0   0   0