619 
fxus62 kmfl 181852 
afdmfl 


Area forecast discussion 
National Weather Service Miami Florida 
252 PM EDT Friday Jul 18 2008 


Aviation... 
isolated to scattered showers and a few isolated thunderstorms will 
continue this afternoon and early evening. But only expecting the 
South Florida terminals to experience vicinity showers...with a 
brief thunderstorm possible. Brief periods of MVFR conditions are 
possible across the South Florida terminals through the evening 
hours...but mainly kmia...kopf...kfxe and kapf. 


60 


&& 


Previous discussion... /issued 228 PM EDT Friday Jul 18 2008/ 


Discussion...a ridge of high pressure extends from the Atlantic 
and across southern Florida while a tropical disturbance heads 
westward across the Caribbean. The ridge axis at the surface 
currently runs from around Grand Bahama to Broward County and 
into Mainland Monroe with the ridge tilted south with height into 
the middle levels. This is allowing the sea breeze to move inland more 
easily in Miami- Dade than in Palm Beach Colorado yet all storm motion 
is generally toward the northeast. This will keep most activity 
concentrated from the western suburbs of West Palm Beach to the 
lake region this afternoon and early evening. This ridge is 
expected to remain in control through the remainder of the 
forecast deepening and increasing the easterly flow as it shifts 
northward, however precipitation chances will slightly increase or 
decrease through the period pending on upper disturbances and 
ridges. The tropical disturbance currently heading east across the 
Caribbean may slightly increase the pressure gradient and increase 
the easterly flow Saturday night and Sunday morning as the 
northern extent of the inverted trough passes by. A slight 
increase in moisture may also occur for far south portions of the 
County Warning Area and East Coast locations during the Saturday night / Sunday 
morning hours as nocturnal thunderstorms may move inland, however 
the bulk of this disturbance is expected to remain well south of 
the area. This slightly extra moisture may also lead to slightly 
more convection along the West Coast sea breeze with the mav 
coming up with around 50 probability of precipitation for Sun afternoon/evening... at this time 
only increased to 40 and will let later shifts make The Jump if 
later guidance continues to increase, but a slightly wetter 
scenario is plausible for the West Coast since an upper trough is 
also expected to drift across the region from east to west. Monday 
and Tuesday an upper ridge may move across the area slightly 
decreasing area probability of precipitation as subsidence occurs, but another upper 
trough may pass over the region middle to late week possibly 
increasing the chance of precipitation yet again. 


Marine...high pressure is expected to generally remain in control 
of area weather through the period with winds at 15kts or less and 
seas at 4 feet or less, however the northern extent of an inverted 
trough is expected to pass South Florida Saturday night/ Sunday 
morning and slightly increase the southeast flow to around 15 kts during 
the night time and morning hours. 


Fire weather...no problems or concerns as typical humid South 
Florida conditions continue. 


&& 


Preliminary point temps/pops... 
West Palm Beach 89 77 91 79 / 30 10 20 10 
Fort Lauderdale 91 80 91 80 / 20 10 10 10 
Miami 91 80 92 81 / 20 10 10 10 
Naples 91 76 93 74 / 20 10 40 20 


&& 


Mfl watches/warnings/advisories... 
Florida...none. 
Am...none. 
GM...none. 
&& 


$$ 


Long term...04/at 
short term/aviation...60/bd