114 
fxus62 kmlb 211944 
afdmlb 


Area forecast discussion 
National Weather Service Melbourne Florida 
240 PM EST Sat Nov 21 2009 


Discussion... 


..threat for rip currents will continue through the weekend... 


Current-tonight...weak area of low pressure in the northwest Gulf 
will continue to slowly advance east along the Gulf Coast states 
overnight...still just west of the Florida Panhandle by daybreak 
sun. Deep layer moisture will increase slightly but convergence is 
still weak. Will continue with low end chance probability of precipitation (30%) for the 
Orlando metropolitan northward and taper slight chance probability of precipitation (20%) southward 
toward Lake Okeechobee and Martin County. Feel...however...that most 
of the coverage warning area will remain dry overnight. Our east- 
northeast low level flow will begin to veer toward the southeast 
late tonight in response to the approach of the low pressure system 
off to the northwest. Presently feel that low overcast (stratus) 
will be more of an issue late overnight than fog. Lows in the lower 
to middle 60s with some upper 60s possible across coastal areas of 
St. Lucie and Martin counties. 


Sun...the weak low pressure system will continue to weaken with its 
slow March east-northeast across the Florida Panhandle through the 
day. A trailing cool front from this low will extend south-southwest 
remaining west of the west central Florida coast. Low-level flow 
will become south-southeast as the system advances ever so closer 
toward the region. Still the feeling here is that the mav guidance 
remains too high with probability of precipitation and will only make minor adjustments to 
pop grid. Will go with 20% along the Treasure Coast and as high as 
35%-40% along and north of the I-4 corridor. Will continue to leave 
out mention of thunder during the day. Though a bit more cloud cover 
will be around don't see anything from allowing maximum temperatures to 
soar to around 80 degrees to the lower 80s across all of east 
central Florida. 


Sun ngt-Tue...h50 trough supporting the surface low continues to 
dampen out significantly as it turns northeastward through the southeastern Continental U.S./ 
Tennessee Valley Sun night. Weak surface wave will redevelop in baroclinic zone 
offshore the southeastern Seaboard early Monday...then slowly edge northeastward. 
Cool front and ascd mean moisture band slow quite a bit over ctrl 
Florida Monday...then only slowly sag across the southern late Monday into Tuesday. GFS 
/NAM guidance show only a weak/strung out h50 vortlobe meandering 
over ecfl. Ketstrk winds are pretty impressive...around 90kt... 
however speed divg ovhd looks rather meager. Have kept probability of precipitation limited 
to 20-30 areawide for Sun night...and only 20 for the southern counties for 
both Mon/Tue. Mainly near 80/l80s areawide for Monday...followed by slight 
cooling over the north and behind the front by Tuesday with highs in the 
upper 70s/near 80 for all but the southeastern cos...where l80s will prevail 
once again. 


Wednesday-Sat (modified previous disc)...longer term models still disagree 
in location of front over the area into middle-late week making for 
continued uncertainty in the extended forecast. Much like 00z... 
the 12z GFS keeps front lingering over south central Florida while 
the 00z European model (ecmwf) drags it northward into North Florida as weak low pushes out 
of the Gulf advecting considerable moisture across the peninsula 
Wednesday/early Thursday. While forecast will continue to stay closer to the drier 
and farther southward placement of the front displayed by the GFS 
..latest trend in the op-GFS is wetter. If this trend continues 
then will need to up probability of precipitation for the ctrl-south for those time periods. 


Guidance then continues to show front getting displaced southward by late 
week as deepening u/l trough builds into the southeastern U.S. With 
cooler temperatures advecting in from a stronger northerly flow. 


&& 


Aviation...mainly VFR...though more concerned for low stratus 
development late overnight toward early Sun morning. Will highlight 
tafs with some late night tempo groups to account for low stratus 
potential. 




&& 


Marine...tonight...N/NE winds at or below 10 kts will veer to the east-southeast-southeast 
overnight with the slow approach of a weak low pressure system 
across the Gulf Coast states. East-NE swells will continue with swell 
periods around 10 second. Seas 3-4 feet near shore and 4-5 feet offshore. 


Sun...winds will veer slightly to the S-southeast as the system marches 
ever so slowly towards the region. Speeds may approach 10-15 kts 
away from the coast during the day. 


Sun ngt-Thu...winds will remain light SW sun ahead of the approaching 
weak low that eventually drags the weak cool front across the ecfl 
coastal waters early this week with winds becoming more north-NE by Wednesday. 
Wind speeds look to remain at or below 15 kts through the forecast period. 
Swells up to 6 feet over the northern offshore waters will subside 
into early next week with wave heights at or below 4ft late Mon-Wed...with 
seas incrsg again Thursday behind secondary Post-frontal nearly surge. 


&& 


Preliminary point temps/pops... 
dab 61 80 65 80 / 30 30 30 10 
mco 62 82 66 81 / 30 30 30 20 
mlb 66 82 67 80 / 20 30 30 20 
vrb 67 82 68 81 / 20 20 30 20 
Lee 64 80 65 81 / 30 40 30 10 
sfb 62 82 65 82 / 30 30 30 20 
orl 65 81 66 81 / 30 30 30 20 
fpr 67 83 66 81 / 20 20 30 20 


&& 


Mlb watches/warnings/advisories... 
Florida...none. 
Am...none. 
&& 


$$ 


Short term...sedlock 
long term....cristaldi 
aviation...sedlock