401 FXUS62 KMLB 121530 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 1030 AM EST Sun Nov 12 2017 .DISCUSSION... Latest RAP40 analysis shows a deep H100-H70 anticyclone centered over the Carolinas with its axis extending SW into the FL Big Bend area, a stalled frontal boundary draped over the south FL Peninsula extending from just south of Tampa Bay to Stuart, and high mean RH values thru the H100-H70 lyr over much of the central peninsula. Morning RAOBs revealed a saturated airmass thru H100-H70...PWat values btwn 1.25"-1.50", almost all of which is trapped blo a sharp subsidence inversion arnd the H70 lvl. Latest wind profiler data shows a solid 20-25KTS of E/NE flow thru 5KFT. With the brisk onshore flow tapping the deep low lvl moisture, intermittent light to moderate shras continus to push onshore arnd 25KTS...bulk of the activity south of Orlando/Cape Canaveral. Rapid motion has limited the QPF potential with most areas generally AOB 0.10"...lcl amounts arnd 0.25". Lcl JAX/MIA pgrad has slackened slightly to btwn 6-7MB, and will continue to do so thru the day as the ridge axis over the SE CONUS steadily weakens. Aside from the diminishing winds thru late aftn, the overall WX pattern is largely unchanged. Slightly lower mean RH values north of Orlando/Cape Canaveral will keep precip chances btwn 20-40pct, while deeper moisture and enhanced lift in the vcnty of the frontal boundary will keep precip chances btwn 50-60pct over the Treasure Coast/Lake-O region. With high moisture trapped blo the H70 inversion, skies will be cldy/mostly cldy, keeping max temps largely in the 75-80F range. Poor beach conditions this aftn as the fresh onshore flow generates rough pounding surf with large breakers btwn 5-7FT. This will pile water behind the sand bar, leading to a frequent and dangerous rip currents. A High Surf Advisory in effect thru 6 PM, a few hours beyond the next high tide cycle. && .AVIATION...Thru 13/12Z. Sfc winds: Thru 12/23Z...coastal sites E/NE 15-19KTS with fqnt G22- 26KTS...interior sites E/NE 11-15KTS with ocnl G18-22KTS. Btwn 12/23Z-13/02Z...coastal sites bcmg NE 8-12KTS with ocnl G18-22KTS... interior sites bcmg NE 6-10KTS. Btwn 13/02Z-13/05...bcmg NE 4-7KTS. Vsbys/WX/Cigs: Prevailing CIGS btwn FL040-060 all sites. Thru 13/00Z...S of KTIX-KISM ocnl MVFR vsbys/cigs in -RA/RA brief IFR vsbys/cigs in RA/BR...N of KTIX-KISM...chc MVFR shras/IFR +shras. Aft 13/00Z...S of KTIX-KISM sct MVFR shras/lcl IFR vsbys/cigs in RA/BR...N of KTIX-KISM slgt chc MVFR shras areas MVFR/lcl IFR vsbys cigs in BR. && .MARINE... Hi pres ridge over the Mid Atlc/Deep South has become elongated over the past 24hrs, weakening in the process. Even so, lcl pres field remains quite tight with a 6-7MB gradient btwn KJAX-KMFL, capable of maintaining a solid 20-25KT E/NE flow. Lcl data buoys show little change in overall conditions over the past 12hrs with seas running 10-12FT in the Gulf Stream, 7-9FT over the shelf waters. While a gradual diminishing wind/sea trend is expected late today-tonight, strong SCA conditions will remain in place thru sunset. No changes to the current SCA configuration. && .HYDROLOGY...(prev disc) The Saint Johns River at ASTF1 has risen further to 2.90FT due to continued impedance/backup of the northward current by the strong winds. With flow having veered more easterly/onshore, there has been some delay in the gauge response, since the flow rate has increased from around 10kcfs to 11.5kcfs since late Friday, even as the river level there has continued to rise. Elsewhere within the MLB HSA, the river level has continued to slowly drop. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...High Surf Advisory until 6 PM EST this evening for Coastal Volusia County-Indian River-Martin-Northern Brevard County- Southern Brevard County-St. Lucie. AM...Small Craft Advisory until 7 PM EST this evening for Flagler Beach to Volusia-Brevard County Line 0-20 nm. Small Craft Advisory until 10 PM EST this evening for Flagler Beach to Volusia-Brevard County Line 20-60 nm-Volusia- Brevard County Line to Sebastian Inlet 0-20 nm. Small Craft Advisory until 4 AM EST Monday for Sebastian Inlet to Jupiter Inlet 20-60 nm. Small Craft Advisory until 1 AM EST Monday for Sebastian Inlet to Jupiter Inlet 0-20 nm-Volusia-Brevard County Line to Sebastian Inlet 20-60 nm. && $$ Short Term/Aviation...Bragaw Long Term/Impact WX...Pendergrast