Marine Weather Net

Deerfield Beach to Ocean Reef, FL Out 20 nm Marine Forecast


REST OF TODAY

E
WINDS
5 KNOTS

TONIGHT

SE
WINDS
5 KNOTS

SUNDAY

ESE
WINDS
5 - 10
KNOTS

SUNDAY NIGHT

S
WINDS
5 - 15
KNOTS

The Marine Weather Forecast In Detail:
AMZ651 Forecast Issued: 1018 AM EST Sat Nov 28 2020

Rest Of Today...East Winds 5 Knots. Seas Less Than 2 Feet. Period 3 Seconds. Intracoastal Waters Smooth. Slight Chance Of Showers.
Tonight...Southeast Winds 5 Knots Along The Coast To East Southeast 5 To 10 Knots In The Gulf Stream. Seas Less Than 2 Feet. Period 2 Seconds. Intracoastal Waters A Light Chop.
Sunday...East Southeast Winds 5 To 10 Knots. Seas Less Than 2 Feet. Period 2 Seconds. Intracoastal Waters A Light Chop. Slight Chance Of Showers.
Sunday Night...South Winds 5 To 15 Knots. Seas Less Than 2 Feet. Period 2 Seconds. Intracoastal Waters A Light Chop.
Monday...Southwest Winds 10 To 15 Knots With Gusts To Around 20 Knots. Seas 2 To 3 Feet. Intracoastal Waters A Light Chop. Chance Of Showers And Slight Chance Of Thunderstorms.
Monday Night...West Southwest Winds 10 To 15 Knots Becoming Northwest 15 To 20 Knots After Midnight. Seas Around 2 Feet Along The Coast And 2 To 4 Feet With Occasional To 5 Feet In The Gulf Stream. Intracoastal Waters A Moderate Chop. Showers Likely And Slight Chance Of Thunderstorms Through The Night.
Tuesday...North Winds 15 To 20 Knots With Gusts To Around 25 Knots. Seas 2 To 3 Feet Along The Coast And 4 To 6 Feet With Occasional To 8 Feet In The Gulf Stream. Intracoastal Waters A Moderate Chop.
Tuesday Night And Wednesday...East Northeast Winds 15 To 20 Knots With Gusts To Around 25 Knots. Seas 2 To 4 Feet With Occasional Seas To 5 Feet Along The Coast And 4 To 6 Feet With Occasional To 8 Feet In The Gulf Stream. Intracoastal Waters Choppy In Exposed Areas.
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AMZ600: Synopsis for Jupiter Inlet to Ocean Reef FL out to 60 nm and for East Cape Sable to Bonita Beach FL out to 60 nm
1018 AM EST Sat Nov 28 2020

A weak area of high pressure over the region will continue to support light winds and generally benign marine conditions across the local waters through this weekend. Early next week, a cold front will approach the area and bring an increase in winds and associated hazardous marine conditions, which will persist until late next week.

Gulf Stream Hazards: None
The approximate location of the west wall of the Gulf Stream as of Nov 28, 2020 at 1200 UTC...
- 2 nautical miles southeast of Fowey Rocks.
- 12 nautical miles east northeast of Port Everglades.
- 6 nautical miles east southeast of Lake Worth.
- 9 nautical miles southeast of Jupiter Inlet.
Area Forecast Discussion
National Weather Service Miami FL
1005am EST Sat Nov 28 2020

Generally quiet weather conditions are anticipated across South Florida today -- with isolated showers possible -- focusing across Miami-Dade and Broward Counties. See below for the details regarding the current and near-term synoptic and mesoscale environment. Happy Saturday!

A broad area of weak low-level high pressure is evident across the region via the latest RAP analysis and GOES-16 water vapor imagery loops. This is supporting very weak low/mid-level flow across southern Florida. The MFL 12Z RAOB (Radiosonde Observation or Upper-Air Observation) captured this weak low-level flow pattern quite well -- depicting a cloud-layer mean wind of 9 knots from the WNW. Aloft, a swath of enhanced mid/upper-level southern steam flow is evident across northern Florida. While there may be some weak upper-level divergence associated with this area of enhanced flow, large-scale forcing for ascent remains nearly negligible across the South Florida CWA.

The large-scale pattern discussed above is supporting a strong 750- mb subsidence inversion -- below which a relatively moist layer is evident via this previously mentioned MFL RAOB (characterized by low-level RH near 80%). This shallow moisture combined with a north-south oriented mesoscale coastal boundary across the Atlantic waters is supporting shallow convective showers with very little in the way of motion. In fact, most of these showers appear to be anchored along the western periphery of the Gulf stream, where localized heat/moisture fluxes are supporting higher theta-e marine boundary layer air.

Considering the relatively rich low-level moisture below the above mentioned inversion and fairly dense cloud coverage/debris over the Atlantic coastal waters, the coastal boundary layer could remain somewhat sheltered from diurnally-driven inland vertical mixing. This could preserve or even allow for a slight increase in surface moisture -- supporting a small uptick in weak surface- based buoyancy along the southeast coast (nearing 500 J/kg this afternoon). Further west, nearly clear skies is supporting efficient surface heating, which should generally mix out the above mentioned rich low-level moisture and actually stabilize these areas to an extent. That being said, areas over western Miami-Dade County/inland South Florida could see isolated showers develop -- owing to the interface of deeper inland boundary-layer mixing and the above mentioned moist/sheltered coastal boundary layer. Therefore, isolated mesoscale driven convective showers will be most possible along the immediate Atlantic coastline of Miami-Dade and Broward Counties, with lower chances extending inland.

Any showers that do manage to develop over land areas today will be shallow in depth -- owing to warm/dry mid-level air and associated strong convective inhibition (SBCINH near -150 J/kg). A lack of any appreciable large-scale forcing for ascent will inhibit parcels from reaching their LFCs within this fairly hostile thermodynamic environment. That said, the very slow/non- existent storm motions and slow propagation vectors will support some light rainfall accumulations across metro Miami-Dade County. The relatively light nature of these showers should greatly limit the threat of urban/street flooding, but if any shower becomes locally enhanced and moves slowly over a particular coastal area, ponding of water could occur, though unlikely.

.Prev /issued 708am EST Sat Nov 28 2020/

Primarily VFR throughout the period, with weak high pressure and light/variable wind flow in place. Shallow moisture may support VFR cigs along the eastern portions of S FL this afternoon, as well as brief passing SHRA. Anticipated coverage of SHRA (rain showers) is too low to mention in the TAFs, but brief MVFR (Marginal Visual Flight Rules) cigs/vis could accompany this activity along the eastern terminals.

Prev /issued 217am EST Sat Nov 28 2020/

Short Term (Today-Sunday)... High pressure over the state will continue to push southward through Sunday, keeping light to moderate E/SE flow at the surface and generally benign boating conditions across the coastal waters. A cold front is expected to approach the area on Monday and bring an increase in showers and possibly a few thunderstorms, along with increasing west- northwesterly winds. The northerly component may bring building seas near the Gulf stream by late Monday and Tuesday.

Surface analysis show weakening high pressure over the central portions of the Florida peninsula and the west Atlantic, which will remain in control of the weather pattern today. Meanwhile, a Low/front system stretches across the Florida panhandle and into the northeast Gulf waters, which is expected to keep slowly migrating southward on Sunday.

Some moisture intrusion started yesterday with a few showers passing through portions of Miami-Dade at times. 00z MFL sounding showed a little higher PWATs (Precipitable Waters) around 1.1 inches, but with a solid 800 mb inversion still in place restricting significant vertical development. Thus, in general, benign weather should again prevail today, with a few passing shallow showers this afternoon and evening, mainly moving inland from the Atlantic waters.

For Sunday, WPC shows the aforementioned Low/front pushing into central Florida, which further weakens the mid level ridging over SoFlo. If this scenario doesn't changes significantly in the next couple of model runs, Sunday should again enjoy fairly benign weather conditions with maybe a little better cloud coverage as the ridge weakens and more moisture ahead of the front filters into the area. For now, will keep POPs in the 20% range at best to cover the chances for passing showers each afternoon. A stronger/deeper trough/front complex is expected to move into the deep SE CONUS and northern Florida beginning Sunday night, but its potential impacts on SoFlo are not anticipated until Monday attm. However, any change in the timing of arrival of this front will require adjusting the forecast philosophy for Sunday afternoon. So, upcoming model runs for the next 24-48 hours will be critical in terms of having a clearer picture of the potential time of arrival of this FROPA event.

Temperatures remain around normals with afternoon highs in the low 80s and morning lows in the mid 60s to low 70s.

Long Term... Sunday Night through Friday Night... A weak ridge aloft will continue to keep benign and quiet conditions across South Florida through Sunday Night. This ridge of high pressure aloft, albeit weak, will keep a weak frontal boundary to the north of our region late this weekend. This weak frontal boundary will stall over Central Florida, before moving northwards as a warm front on Sunday Night/Monday Morning. A surface low will develop along the warm front boundary in the Gulf of Mexico, and accelerate to the northeast. The trajectory and speed of this surface low, has implications on the potential weather impacts we may see across South Florida. If the surface low takes a faster and further north trajectory, the track would place the best dynamics for greater impacts to the north of our area. If the surface low takes a slower and more southerly trajectory, the track would place the best dynamics a little closer to our area, and could potentially see a greater impact.There are still differences in the exact placement of the low between the GFS and the European models at this time, with that being said, it will be important to continue watching the trends with the surface low and the passage of the associated cold front.

Behind this front, a cool and dry air mass will move into South Florida on Monday Night/Tuesday Morning. Although the cold front will pass through during this time, the coldest night will be on Wednesday when the cold air advection will be the strongest. There are some notable differences between the GFS and the European models during this time frame. The latest European model has temperatures in the 40s across the interior with temperatures near 50 along the east and west coast of South Florida. The latest GFS model is a little warmer with lows in the upper 40s west of the lake, 50s across the rest of the interior and the west coast, and temperatures near 60 degrees along the east coast. It will be important to continue to monitor changes in the forecast as we move closer in time to this period.

After the passage of the front and subsequent cold air advection, a warming trend will begin on Thursday as a high pressure aloft progresses to the northeast. This will shift the overall flow to the east and then southeast, which should allow for increased moisture across the area. The GFS and the European models both show a second front progressing eastwards across the Gulf of Mexico on Thursday with a potential passage across South Florida late week/ next weekend. It is too early to speculate on the passage of this front, but this may be something to monitor in future discussions.

Marine... High pressure over the state will continue to push southward through Sunday, keeping light to moderate E/SE flow at the surface and generally benign boating conditions across the coastal waters. A cold front is expected to approach the area on Monday and bring an increase in showers and possibly a few thunderstorms, along with increasing west- northwesterly winds. The northerly component may bring building seas near the Gulf stream by late Monday and Tuesday.

Beach Forecast... Moderate easterly winds and a remnant swell will keep rip current potential at the moderate level through this evening at all beaches of Palm Beach County. Afterward, risk remains low through mid week when increasing NE/E winds will bring back an elevated risk for the Atlantic beaches.

NOAA Miami FL Office: Watches - Warnings - Advisories
FL...None. AM...None. GM...None.