Scientific Forecaster Discussion
fxus62 kmlb 150225
Area forecast discussion
National Weather Service Melbourne Florida
925 PM EST Thu Nov 14 2019
The 15/00z soundings tell the story: airmass is at or near
saturation acrs central and North Florida...and thru the h100-h70 lyr
over South Florida...a noteworthy slug of dry air btwn h70-h30 on both
kmfl/keyw soundings. Frontal boundary stalled over South Florida ahead of
a dvlpg storm system over the ern Gomex...classic "triple point" due
east of the Florida sun coast. This low is positioned under the ascending
right rear quadrant of an 80-90kt h30-h20 jet streak extending from
the wrn Gomex to the Carolina coast. LCL wind profiles showing a
serly flow thru 10kft, veering to SW abv.
Weather set up is classic of warm sector isentropic "overrunning" that
results in widespread stratiform precip with LCL pockets of enhanced
instability generating isold tsras. Indeed, radar imagery for the
past few hrs shows a large stratiform rain shield advecting onshore
over west FL, extending back into the southeast Gomex...enhanced
reflectivity over the ern Gomex, possibly triggered by the ern edge
of The Loop current. This rain will gradually spread into east
central Florida overnight as the storm system dvlpg over the Gomex lifts
acrs the Florida Peninsula. Ahead of the low, low lvl onshore flow will
combine with the nearly saturated airmass to allow sct shras to dvlp
over the LCL Atlc and push onshore.
High precip chances overnight, especially north of the Treasure
Coast/lake-o region as the sfc low tracks up the I-4 corridor. Mid
lvl cool/dry air over South Florida may push far enough north to further
destabilize the airmass, allowing LCL energy impulses to generate
isold tstorms. The track of the low also will force the low lvl east/southeast
flow to become increasingly southerly overnight. Combined with
cldy/mcldy skies, min temps should remain close the their current
dewpoints in the u60s/l70s.
A few minor tweaks with the evng update...increasing pops a touch
over the Treasure Coast/lake-o region and increasing min temps north
of the I-4 corridor to the u60s. Overall fcst message will be nearly
the same...warm and rainy.
Sfc winds: thru 15/08z...north of kism-ktts east/NE 5-8kts bcmg east 5-8kts...
S of kism-ktts east/southeast 5-8kts. Btwn 15/08z-15/11z...bcmg S/southeast 5-8kts.
Btwn 15/11z-15/14z...bcmg S/SW 6-9kts. Btwn 15/14z-15/17z...bcmg
west/SW 7-11kts. Btwn 15/17z-15/20z...north of kism-ktts bcmg west/northwest 7-11kts.
Vsbys/wx: thru 15/06z...chc MVFR vsbys in ra/br. Btwn 15/06z-
15/12z...north of kmlb-ksef nmrs MVFR shras/slgt chc IFR tsras...S of
kmlb-ksef...sct MVFR shras/slgt chc IFR tsras. Aft 15/12z...nmrs
MVFR shras/slgt chc IFR tsras.
Cigs: thru 15/12z...cigs btwn fl060-080 ocnl MVFR cigs btwn fl020-
030. Aft 15/12z...north of kism-kmlb MVFR cigs btwn fl010-020 ocnl IFR
cigs btwn fl006-010...S of kism-kmlb VFR cigs btwn fl040-060 ocnl
MVFR cigs btwn fl020-030.
sfc low dvlpg over the ern Gomex will lift acrs the Florida Peninsula
overnight. This will force winds to shift from a moderate to fresh
serly breeze to gentle to moderate srly breeze by daybreak. East/NE
swells btwn 4-6ft will maintain hazardous seas for small craft, even
as winds diminish and veer to an slight offshore component. Combined
seas 5-7ft over the shelf waters and 6-8ft over the Gulf Stream,
subsiding to 4-6ft and 6-7ft, respectively. No changes to the
current Small Craft Advisory configuration. Sct-nmrs shras and isold tsras.
Am...Small Craft Advisory for hazardous seas until 4 am EST Friday
for Sebastian Inlet to Jupiter Inlet 0-20 nm-Volusia-
Brevard County line to Sebastian Inlet 0-20 nm.
Small Craft Advisory for hazardous seas until 10 am EST Friday
for Flagler Beach to Volusia-Brevard County line 20-60 nm-
Sebastian Inlet to Jupiter Inlet 20-60 nm-Volusia-Brevard
County line to Sebastian Inlet 20-60 nm.