Area Forecast Discussion
Issued by NWS Melbourne, FL

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
000
FXUS62 KMLB 261355
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
955 AM EDT FRI AUG 26 2016

.DISCUSSION...

Persistent pattern as high pres ridge over Mid/Deep south remains
the dominant WX feature for central FL. Deep lyr NE flow around the
leading flank of the ridge has advected a dry/stable continental
airmass into north FL, resulting in a steep moisture gradient acrs
the peninsula. Morning RAOBs reflect this with PWat values btwn
1.25"-1.50" at KJAX/KTAE, incrsg to arnd 2.00" at MYNN/KXMR/KTBW, to
over 2.25" at KMFL/KEYW. RAP40 confirms much of this moisture is in
the low lvls with H100-H85 dewpoint depressions btwn 2-3C over most
of the peninsula, increasing to 5-7C over the panhandle.

Aloft, the lcl airmass showing a little more instability from recent
days. Latest sat imagery shows a large slug of moisture with just
north of the Bahamas associated with a local H85-H50 vort max. H30-
H20 divergence shows a band of moderate to strong divergence over
central FL associated with the ascending left front quad of an
easterly 40KT jet streak over S GA. Mid lvl thermodynamic support has
increased as well...H70 temps btwn 10-11C indicative of low/mid lvl
thermal capping, but H50 temps btwn -6C/-7C are generating mid lvl
lapse rates arnd 6.5C/KM acrs much of central FL.

Morning RAOBS indicate convective temps in the M/U80s...avg for late
summer. Enhanced moisture over the Atlc will advect onshore under
the deep E/NE flow. While such flow patterns generally do not
promote strong convection, given the steeper lapse rates and
enhanced upr lvl divergence, will need to watch for increased
potential for strong downburst winds in passing shras/tsra. Morning
fcst package has a good handle on the situation based on latest
radar trend. Will update fcst to refresh wording...no substantive
changes necessary.

&&

.AVIATION...Thru 27/12Z.
Sfc Winds: Thru 27/00Z...E/NE 10-14KTS with ocnl sfc G18-22KTS. Btwn
27/00Z-27/03Z...bcmg NE 3-7KTS. Btwn 27/12Z-27/15Z...bcmg E/NE 8-
13KTS.

Vsbys/WX/Cigs: S of KTIX-KISM...thru 27/00Z sct-nmrs MVFR
shras/isold IFR tsras...aft 27/00Z chc MVFR shras/slgt chc IFR
tsras. N of KTIX-KISM...thru 27/00Z isold-sct MVFR shras/isold IFR
tsras...btwn 27/00Z-27/12Z slgt chc MVFR shras...aft 27/12Z chc MVFR
shras/slgt chc IFR tsras.

&&

.MARINE...
Latest sfc obs show a lcl pgrad capable of supporting 15KTS of NE
wind...confirmed by the wind trend at Buoy009 since daybreak. Large
hi pres ridge over the Mid/Deep South will maintain long NE fetch
over the W Atlc, a fetch that has pushed a 4-5FT swell into the east
FL Atlc waters. Wind chop on top of the swell will produce poor
conditions for small craft operation, especially over the offshore
waters where Buoy009 has recently topped the 6FT mark with 7-8sec
dominant pds. Given the trend, will bump the offshore Atlc waters N
of Sebastian Inlet into the 4-6FT range and hoist a cautionary
statement for small craft.

&&

.MLB Watches/Warnings/Advisories...
FL...None.
AM...None.

&&

$$

Public/Marine Wx.....Bragaw
Aviation/Impact Wx...Johnson
Tropical Desk/DSS....Kelly



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.