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Area forecast discussion 
National Weather Service Melbourne Florida 
219 PM EDT Sat Mar 20 2010 


Discussion... 


..boating conditions deteriorate Sunday... 
..Chance for strong storms Sun afternoon/evening... 


Tonight should start out partly cloudy as daytime cumulus dissipates. 
Southeast flow shifts to the south as the high pressure center 
located off northeast Florida continues to move away from the 
peninsula and the cold front associated with a developing area of 
low pressure over the lower Mississippi River valley and Gulf Coast 
states continues pushing eastward. Diffluent middle and upper level flow 
will increase middle and high level cloudiness toward sunrise. 
Overnight lows around their climatology values of lower 50s northwest and 
Volusia to the middle and upper 50s over the southern half of the 
forecast area and along the coast Cape Canaveral south. 


Sunday...a cold front associated with an occluding low pressure 
system moving across southeast states will track across the Gulf 
Coast states and into the Florida Panhandle during the morning then 
reach the peninsula during the late afternoon. In spite of prognosticated 
helicity values in the 300 to 400 unit range along with a 40 to 50 
knot low level jet moving through the area and dew points in the 
60s...early cloud cover may limit instability and we may wind up 
with strong gusts associated with storms. For this zone package 
am going with likely or higher pop with gusty winds being the main 
weather hazard and will let the next shifts ramp up threats if 
necessary...after watching the frontal boundary and dynamics a 
little longer. 


Sun night...models show main cluster of strong convection shifting 
offshore about the north half of the area by early evening...but 
the complex should trail southwestward and affect southern 
sections as southern portion of the front slow down. The area 
should come under right rear quadrant of upper jet...which may 
cause the rainfall to persist much of the night...especially 
across the south half. Have inherited 60 percent probability of precipitation areawide but 
the latest guidance has 40 north and 70 south. Will not change the 
forecast until this trend becomes a little more clear. Generalized 
rainfall totals for this system look to be a half inch to one and 
a half inches...with locally higher amounts in the strongest 
storms. 


Monday...some rainfall is expected to linger in the morning hours 
especially across the south half...where chance probability of precipitation that are in 
the current forecast will not be changed. The latest GFS then 
dries things out in the afternoon and west flow could become quite 
gusty. Considerable stratocu should linger in the low level 
cyclonic flow...which will probably result in temperatures struggling to 
reach the lower 70s in the north and middle 70s in the south. 


Tue-Thu...high pressure will build toward the Florida Peninsula 
on Tuesday and prognosticated to be overhead Wednesday which will serve to ease the 
winds though offshore flow may hold off the sea breeze again on 
Tuesday. Onshore flow will redevelop Wednesday and Thursday. Will keep conditions 
dry through the period. Temperatures behind rebounding to the upper 70s 
by Thursday with a few 80 degrees over the interior. Lows in the upper 
40s and lower 50s Monday night through Wednesday night. 


Fri-Sat...high pressure is forecast to shift offshore Friday and 
begin a southerly return flow of moisture. A quick moving 
shortwave trough is prognosticated to bring chance probability of precipitation late Friday and Friday 
night. No strong cooling is indicated behind the trough with temperatures 
staying at or a little above normal. 


&& 


Aviation...few-scattered fl035-050 through 21/05z (midnight). 
Few-scattered below Florida 020 as winds shift to the south and start to 
increase. MVFR after 21/12z(sunday 8am in the strengthening south to 
southwest flow ahead of a cold front pushing across the western 
Panhandle and eastern Gulf. 


&& 


Marine...National oceanic and atmospheric administration and scripps buoys recording 2 to 3 foot seas and the 
National oceanic and atmospheric administration buoys recording light winds. Conditions to start going downhill 
after midnight as the winds shift to the south and increase in 
advance of a line of storms and a cold front that are forecast to 
track across the eastern Gulf and the state Sunday. Small Craft 
Advisory conditions are expected during the late overnight 
hours...ie after 2 am Sunday. 


Mon-Thu...gusty west winds are expected behind front on Monday then 
easing up gradually on Tuesday. High pressure ridge nosing in on Wednesday 
should provide less than 10 knot winds...then as the ridge builds 
offshore to our north on Thursday a 10 knot onshore flow is projected. 


&& 


Fire weather...red flag warning for durations of low relative 
humidity is currently in effect for the interior and will expire no 
later than 7 PM Saturday. 


Sunday...wet day on tap as showers and storms associated with an 
advancing cold front are forecast to impact the area during the 
afternoon. 


Mon-Thu...the latest guidance indicates min relative humidity values around 40 
percent on Monday...around 35 percent on Tuesday and 35-40 percent Wednesday- 
Thursday. Quite gusty west winds Monday will start to diminish on Tuesday then 
light/variable winds are forecast Wednesday becoming light onshore Thursday. 


&& 


Preliminary point temps/pops... 
dab 60 77 53 71 / 10 80 60 20 
mco 57 78 55 71 / 10 70 60 20 
mlb 63 80 53 72 / 10 70 60 30 
vrb 64 80 56 75 / 10 60 60 40 
Lee 56 77 55 72 / 10 80 60 20 
sfb 57 79 55 71 / 10 80 60 20 
orl 57 78 56 71 / 10 70 60 20 
fpr 64 80 56 74 / 10 60 60 40 


&& 


Mlb watches/warnings/advisories... 
Florida...red flag warning until 7 PM EDT this evening for inland Volusia- 
Northern Lake-Orange-Osceola-Seminole-Southern Lake. 


Am...Small Craft Advisory from 6 am Sunday to 6 am EDT Monday 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. 


&& 


$$ 


Short term/aviation...Wimmer 
long term....lascody 

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