Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Melbourne Florida
253 PM EDT Wednesday Jul 29 2015
tonight-Friday night...middle level/500mb high centers over the Southern
Plains and the Desert Southwest and in the Atlantic southeast of
Florida move little as does the middle level/500mb troughing over
Florida between the two high centers. Impulses of middle level
energy/vorticity continue to move southwest to northeast over
Florida. Surface troughing stretching from the north central Gulf of
Mexico across southern Georgia North Florida and along the U.S. East
Coast moves little this period. Precipitable water values are
forecast to remain at or above 2 inches for central Florida. Current
60 pop for Thursday and Friday looks good. As in previous
days...lingering isolated/scattered light rain or an isolated storm
through middle evening Wednesday and Thursday then some breaking of the
cloudiness after midnight. Highs around 90 and lows in the middle and
Weekend...plains middle/upper anticyclone will slowly retrograde while
trough gradually digs in over the eastern Continental U.S.. weak cut off low
east of the waters early should shear out by Sunday as the eastern
trough digs. The models do not show much subsidence/drying on the
back side of this low and keep precipitable water values 2 inches or
greater through most of the period. Additionally...middle level temperatures
will cool slightly to around minus 7 celsius. Expect this will lead
to an overall greater coverage of storms with increased lightning
Steering flow will gradually weaken...but with low level ridge
suppressed to the south providing southwest flow...sufficient
focusing for storms will exist over the eastern side of the
MOS/consensus probability of precipitation are about 50-60 percent through the period and
see no reason to differ from them.
Mon-Wed...the models show Atlantic ridge building back across the
peninsula Wednesday as the eastern Continental U.S. Trough lifts and southern
extension into Florida shifts west over the Gulf of Mexico. This
represents a delayed trend though...so expect moisture to remain
high and probability of precipitation 50 percent or a little higher seem warranted...except
possibly trending lower Wednesday...if ridge does indeed build back into
scattered rain showers/isolated thunderstorms and rain with tempo IFR ceilings/visibilities with any convection
with a few gusts to 35kts. Vicinity of taf sites still a good call
for the afternoon. Patches of leftover light rain from earlier
storms through middle evening. Low clouds from around 09z/late
overnight through 14z/middle morning Thursday.
buoys recording southwest winds 5 to 10 knots at the coast
and nearshore...and 15 to 20 knots at buoy 010 at 12nm offshore. The
outlier was the cman at Saint Augustine where the wind was northwest
at 5 to 10 knots.
Winds forecast to shift to the northwest and north during the day as
low pressure off northeast and central Florida tracks east into the
Atlantic. Winds look light enough to allow for an onshore wind
down to at least Sebastian Inlet in the afternoon.
Thu-Fri...surface ridge axis will remain suppressed to the south.
The pressure gradient looks like it will support southwest winds
around 10 knots near shore and 10 to 15 knots in the outer waters.
Middle level wind flow is forecast to weaken but winds in the lower
portion of the atmosphere out of the west look sufficient to push
storms off the peninsula into the Atlantic waters. Coverage looks
rather high and storms should start to produce more frequent
Weekend...little change in the moist southwest wind flow regime.
Boaters should continue to be vigilant for marine storms...
especially during the afternoon and evening.
Preliminary point temps/pops...
dab 74 92 74 90 / 20 70 30 50
mco 75 90 75 91 / 20 70 30 50
mlb 74 90 74 90 / 20 70 40 60
vrb 73 91 73 89 / 20 70 40 70
Lee 77 91 76 91 / 20 70 30 50
sfb 76 92 75 91 / 20 70 30 50
orl 76 91 76 91 / 20 70 30 50
fpr 72 90 73 89 / 20 60 50 70