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Area forecast discussion 
National Weather Service Melbourne Florida 
238 PM EDT Wednesday Mar 17 2010 


Discussion... 


Water vapor loop showing large area of middle/upper level dry air over 
the Gulf of Mexico was wrapping around a complex upper level low 
pressure system the covered the southeast and middle Mississippi River 
valley regions. At the surface...broad area of low pressure 
troughing stretched from the low pressure system well east of the 
Canadian Maritimes to Florida and into the eastern Gulf. Vorticity 
maxes embedded in the fast west to east middle and upper level flow 
will work their way down to the surface and spin up an area of low 
pressure in the eastern Gulf and deepen it as it moves quickly 
across the peninsula and into the Atlantic overnight. 


For tonight...winds will to the west and increase sharply as the low 
deepens in the Atlantic of east central Florida. Overnight lows in 
the 40s still several degrees cooler than their usual 50s. 


Thursday...nice day inspite of temperatures maxing out in the 60s 
due to brisk chilly west winds 10 to 15 miles per hour. May see more low clouds 
over the northern areas due to wrap around moisture from the low off 
northeast Florida. 


Thursday night...stacked middle level low and surface low pressure will nudge 
slowly offshore from the Carolina coast keeping west/west-northwest winds near 10 
miles per hour in the evening and 5-10 miles per hour overnight. Lows will be below normal 
in the middle to upper 40s. 


Friday...surface low will pull further offshore leaving a weakening 
pressure gradient in its wake with surface high pressure over the eastern 
Gulf of Mexico. Should be mostly sunny with northwest winds in the morning 
becoming onshore near the coast in the afternoon. Pleasant high 
temperatures in the Lower-Middle 70s. 


Sat...surface high pressure will shift slowly eastward over the Florida 
Peninsula. Expect to see a gradual warming trend ahead of the next 
front with highs in the middle-upper 70s with a cool sea breeze keeping 
temperatures in check along the East Coast. Should be mostly sunny 
with light winds in the 5 to 10 miles per hour range. 


12z guidance generally in line with previous 06z/00z guidance for the 
extended period. Have trimmed back Sun night probability of precipitation to evening period 
as front and precipitation chances should move through by around midnight. 


Sun...southwest flow aloft on sun ahead of an approaching cold front 
across the Gulf Coast states. Upper energy weakens as this boundary 
moves through the area Sun night. Winds will become light south to 
southeasterly early in the day and veer to more southwesterly by 
late in the day. Atmospheric profiles still slightly stable so will 
keep absent mention of thunder and keep a slight chance mention for 
mainly afternoon showers with greatest chances near and north of the 
Orlando theme Parks. Will see increasing cloudiness through the day on 
sun though highs will still be able to make it into the middle/upper 
70s with a few 80 degree readings possible across Okeechobee County 
and the Treasure Coast. Will keep a 30% mention of showers in for 
mainly the evening until the boundary moves through the area. Lows 
mainly in the upper 50s with lower 60s possible along the coast 
south from the cape. 


Mon-Tue...mainly zonal flow aloft during this time. High pressure 
will expand into the Gomex toward the Florida Peninsula on Monday to 
over the southeast U.S. On Tuesday. Will keep conditions dry through 
this period. Northwest winds on Monday behind the latest system will 
continue to veer northeast Monday night and easterly on Tuesday into Tuesday 
night. Maximum highs falling back into the upper 60s to lower 70s on Monday 
rebounding to Lower/Middle 70s by Tuesday. Lows in the upper 40s to 
lower 50s Monday night and middle/upper 50s Tuesday night...except lower 
60s along the Treasure Coast. 


Wednesday...500 mb heat rises to 586/587 dm and strengthening southeast low level 
flow ahead of the next system will yield a warm day with highs in 
the upper 70s to around 80 southern interior. GFS indicates some light quantitative precipitation forecast 
portending the development of some shower lines over the Atlantic in the 
breezy southeast flow but will not add this yet to the new day7 forecast. 


&& 


Aviation...mainly VFR conditions. 


&& 


Marine...area buoys recording variable winds 5 to 10 knots and 2 to 
4 foot seas mainly comprised of 2 to 3 foot long period northeast 
swells. Winds will shift to the south and increase to 10 to 15 knots 
as an area of low pressure over the eastern Gulf moves across the 
Mainland and off the northeast/east central Florida coast this 
afternoon and evening. 


Tonight and Thursday...expect wind shift to the west and increasing 
wind speeds this evening as the low deepens while moving away from 
Mainland Florida. Small Craft Advisory for the offshore waters 
(beyond 20 miles of shore) by 8pm this evening. Winds inside 20 nm 
of shore will pickup to around 15 knots beyond a few miles of shore. 


Expect winds to 20 knots offshore Thursday night into early Friday with 
advisory continuing beyond 20 miles from the coast. Surface high 
pressure building over the area by Sat will lessen winds and seas by 
Sat afternoon. Next front following quickly on the heels of the last 
system for Sunday. Winds increase again behind the front for Sunday 
evening and Sunday night across the offshore waters to around 20 
knots. 


&& 


Fire weather...no fire weather concerns Thursday as west winds will pull 
Gulf moisture across the peninsula and with maximum temperatures only in 
the 60s min relative humidity values should get no lower than in the 
40-50 percent range. Fire Weather Watch continues across interior 
sections on Friday with long duration of low relative humidity expected. 


&& 


Preliminary point temps/pops... 
dab 49 65 47 71 / 30 20 10 0 
mco 50 68 48 75 / 20 20 10 0 
mlb 47 68 46 71 / 20 20 10 0 
vrb 48 70 45 73 / 20 20 10 0 
Lee 50 68 47 73 / 20 20 10 0 
sfb 51 67 48 74 / 20 20 10 0 
orl 51 68 49 74 / 20 20 10 0 
fpr 50 70 46 73 / 20 20 10 0 


&& 


Mlb watches/warnings/advisories... 
Florida...Fire Weather Watch from Friday afternoon through Friday evening 
for inland Volusia-Northern Lake-Okeechobee-Orange-Osceola- 
Seminole-Southern Lake. 


Am...Small Craft Advisory from 8 PM this evening to 10 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. 


&& 


$$ 


Short term/aviation...Wimmer 
long term....volkmer 

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