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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Wednesday
• 
• High: 84 °
• Low: 72 °
• T-Storms

• Thursday
• 
• High: 81 °
• Low: 72 °
• Chance of T-Storms

• Friday
• 
• High: 84 °
• Low: 73 °
• Chance of T-Storms

• Saturday
• 
• High: 82 °
• Low: 70 °
• Chance of T-Storms

• Sunday
• 
• High: 82 °
• Low: 73 °
• Chance of T-Storms

Area forecast discussion 
National Weather Service Miami Florida 
1026 am EDT Wednesday may 16 2012 


Update... 
only slight modifications were necessary this morning based on the 
latest trends and observations around the local area...mainly for 
the morning rainfall distribution and chances. The morning 
surface analysis showed the local area positioned between a weak 
trough to the northwest and a ridge axis...which has resulted in a 
very weak pressure gradient with light SW flow. The latest water 
vapor loop showed a positively-tilted upper trough extending SW 
over the lower MS valley to the Texas coast and a ridge axis 
extending north over the western Atlantic. Plenty of middle to upper 
moisture spreading northeast across the Florida Peninsula between these 
two upper features will continue to support cloudy conditions 
today. The morning upper air mfl sounding indicated a nearly 
saturated layer between 600-400 mb with Uni-directional SW flow 
through the column. Although the overcast conditions will limit 
the daytime heating and instability...with the upper trough 
approaching from the west and heights steadily falling...the 
probability for thunderstorms will remain in the 
forecast...especially over the eastern half of the Florida 
Peninsula later today. 85/ag 


&& 


Previous discussion... /issued 730 am EDT Wednesday may 16 2012/ 


Aviation...moist SW wind flow aloft at this time pulling ample 
moisture over south fla. Spotty light rain across the area this 
morning then scattered thunderstorms possibly developing this 
afternoon, although cloud cover could limit activity. Some brief 
IFR conditions possible in heavier thunderstorms with winds gusts 
possible > 40 kts, but not in tafs at this time. Surface winds 
generally calm to variable < 5 kts but a weak SW wind flow after 12z 
could develop but less than 10 knots. Along the East Coast a southeast sea 
breeze expected after 17z but again less than 10 knots. At 
kapf...thunderstorms expected to develop after 16z but inland from 
terminal so only vcsh at this time. Surface winds easterly less 
than 10 knots through 16z then SW sea breeze developing at 10 
knots. 


Previous discussion... /issued 341 am EDT Wednesday may 16 2012/ 


Discussion... 


The latest infrared satellite imagery shows the deepest convection over 
the eastern Gulf west of the Tampa area this morning. This is consistent 
with the upper level wind pattern which becomes most divergent 
over the central portions of the Florida Peninsula. This is due to 
the interaction of an upper level high pressure over the southern 
Caribbean Sea with a trough of low pressure located over the south 
central US. A jet stream of about 80 to 90 knots is observed over 
the northern Gulf of Mexico between these two features. All models 
agree on moving the deepest moisture across central Florida for 
Wednesday morning, especially between daybreak and late morning. 
The implications of this could be a delay in convection for 
Wednesday as well as slightly lower high temperatures. To account 
for the effect of cloud cover on temperatures for Wednesday went 
with a blend of dynamical and statistical model for high 
temperatures. Overall there is very good confidence in the short 
term forecast on regard to the increased cloud cover and wet 
conditions. However, it is always difficult to identify the exact 
location and timing of convection. The evolution of cloud cover 
and location and coverage of morning showers will determine the 
exact characteristics of the evening convection. Over the past 
few days we have observed that the heaviest showers and 
thunderstorms have been happening around the lake and in Palm 
Beach County. In addition to the preferred precipitation in this 
area, due to the S-SW wind flow, the northern portions of the County Warning Area 
also have been about 1 to 1.5 c colder than the southern sections. 
This is believed to have contributed to stronger showers over the 
northern sections. The same pattern in 500 mb temperatures is 
forecast for the next few days. 


There is less confidence in the extended forecast due to the 
effect of an area of upper level low pressure that remains 
detached of the westerlies from Thursday into the weekend over the 
southeast US. For the past few days, the GFS and European model (ecmwf) disagreed on the 
precipitation forecast...with the GFS forecasting a drier weekend. 
However, the current forecast shows both models indicating that 
plenty of moisture is forecast to stay over parts of the southeast US and 
Florida. With winds a bit more easterly on the weekend this should 
maintain most of the afternoon convection over the central or 
western portions of South Florida...but outflow boundaries and 
abundant moisture could lead to some showers near the East Coast 
metropolitan areas over the weekend. 


Marine... 


Light winds are expected through Friday over all of the local 
waters of South Florida. This will keep the seas at 2 feet or less 
in both the Atlantic and Gulf waters of South Florida. There is also 
a chance of showers and thunderstorms each day this week over the 
local waters of South Florida...which may lead to brief periods with 
gusty winds and locally choppier conditions. 


Aviation... /issued 129 am EDT Wednesday may 16 2012/ 


Aviation...moist SW wind flow aloft at this time continuing to 
pull ample moisture over south fla. Expect some showers to 
develop affecting Miami Dade terminals and kapf before 12z but 
expect VFR conditions through 16z all terminals. After 16z interior 
convection to develop and with steering winds aloft SW...the 
showers/thunderstorms will move NE affecting all East Coast 
terminals with MVFR ceilings/visibility and prob30 in all East Coast 
tafs after 18z. Some brief IFR conditions possible. Surface winds 
at this time calm to variable < 5 kts but a weak SW wind flow after 
12z but less than 10 knots. A southeast sea breeze expected after 17z but 
again less than 10 knots. At kapf...thunderstorms expected to 
develop after 16z but inland from terminal so only thunderstorms in the vicinity through 21z 
then vcsh at this time. Surface winds easterly less than 5 knots 
through 16z then SW sea breeze developing at 10 knots. 


Fire weather... 
plenty of moisture will preclude any chance for red flag 
conditions each day through the forecast period. 


&& 


Preliminary point temps/pops... 
West Palm Beach 86 72 85 72 / 70 40 60 40 
Fort Lauderdale 86 74 85 74 / 70 30 60 30 
Miami 86 73 85 74 / 60 30 50 30 
Naples 85 71 85 72 / 50 20 40 20 


&& 


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


$$ 


Discussion/marine/fire...85/ag 
aviation/radar...57/dg