Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Melbourne Florida
1017 am EDT sun Aug 30 2015
..heavy rain and flooding threat continues through Monday...
Today...tropical air mass in place with GPS precipitable water
values at least 2.2 to 2.3 inches. The 12z surface analysis showed
an inverted trough (remnants of erika) extending from the Lower Keys
to South Florida. This low level trough likely extended even farther
northward to near Cape Canaveral since the buoys offshore were
showing breezy southeast flow while our northern land areas were
light in the early morning hours.
Northern Bahama convergence lines and coastal convergence have led
to a few rounds of showers/storms along the coast this morning.
Expect this will continue into the afternoon as satellite was
showing a larger scale outflow boundary approaching Grand Bahama
from the south...which will likely generate some larger clusters of
The interior has been brushed by a few showers this morning and
there were likely some outflow boundaries pressing inland from the
coastal convection. Expect with the high moisture in place and
modest heating through late morning there will be a rather large
cluster of storms developing. The hrrr model has been showing this
blowup lifting northward up the interior with some affecting the
coastal counties too.
This setup along with some divergence aloft will lead to a high
coverage of rainfall across the entire area. Locations that receive
several rounds of showers/storms could have rainfall totals 2-3
inches...so Flood Watch in place looks good.
We could just about ring the Bell today and go with 100 percent
probability of precipitation. Do not plan any significant changes to the previous forecast
package though...which shows anomalously high 90 probability of precipitation. With all the
rain and clouds...temperatures will have trouble reaching the upper 80s and
might have to tweak readings down a few degrees here and there.
Aviation...no changes to previous discussion
High coverage of showers and storms expected across the region today
with a very moist tropical airmass in place. Greatest coverage and
best chance for reductions to IFR/MVFR conds will be along the coast
in the morning...then expect widespread shower/scattered storm coverage
across the entire area into the after. Rain chances decrease across
the interior past midnight with showers and storms remaining likely
along the coast.
Today/tonight...poor to hazardous boating conditions will occur as
remnant low pressure trough from Erika...near South Florida...produces
gusty southeast winds. Wind speeds 15 to 20 knots will build seas up
to 6-7 feet offshore. In addition widespread showers and scattered
storms with gusty winds will continue to develop and move north to
northwest over the waters.
Though the stormy weather conditions should keep most small craft in
port...there is a Small Craft Advisory in effect for the Treasure
Coast waters and offshore Brevard County...with exercise caution
Hydrology...no change to the previous discussion
Rainfall totals around to 2 to 4 inches are forecast across east
central Florida through Monday night with locally higher amounts up
to 5 to 6 inches possible. Main concerns for any flooding will be
along the coast from Brevard southward where any persistent rain
bands can develop. Also...Shingle Creek at Campbell (shif1) is only
about 0.2 feet below action stage. Any additional heavy rainfall
totals across the Shingle Creek basin today may produce minor
flooding at this site and will have to be monitored closely.
Florida...Flood Watch through Monday evening for coastal Volusia County-
Indian River-inland Volusia County-Martin-northern Brevard
County-Northern Lake County-Okeechobee-Orange-Osceola-
Seminole-southern Brevard County-Southern Lake County-St.
Am...Small Craft Advisory until 8 PM EDT this evening for Sebastian
Inlet to Jupiter Inlet 0-20 nm-Sebastian Inlet to Jupiter
Inlet 20-60 nm-Volusia-Brevard County line to Sebastian
Inlet 20-60 nm.