Marine Weather and Tide Forecast for Jupiter Island, FL

DISCUSSION
Issued at 207 AM EDT Sat Mar 14 2026

-----------Synoptic Overview-----------

Broad west-southwesterly mid-level flow exists over Florida this morning. The state resides well south of a strong, zonal polar jet over the northern tier of states. A weak subtropical jet extending across the southern Gulf is set to carry weak ripples of vorticity maxima over the state through this weekend. In the boundary layer, mesoanalysis finds a weak trough and cyclonic flow at H925 to H85 over the southern half of Florida. This is roughly where an old cold front has dissipated, draping a moisture discontinuity. At the coast, low-level onshore flow opposes offshore flow near 10 kft, which may favor banded precipitation should deeper convection develop.

Over the next couple of days, expect northward advection of the moisture sitting across South Florida as the flow turns southeasterly to southerly. This will occur as an intense (160 kt)
jet streak at H3 dives from the Pacific Northwest, carving out a sharp trough over the Plains. Combined with seasonably cool mid- level temperatures, lapse rates will be sufficient for moderate convective instability over the peninsula, particularly on Sunday.

By Monday morning, a full-latitude neutral-tilt trough will have formed over the Ohio Valley, with its cold front likely extending from W Virginia to the Florida Panhandle. This will be a powerful storm, with a surface reflection potentially reaching sub-980 mb.
This feature may deliver 3+ ft snows over the portions of the Great Lakes and a significant severe weather episode over portions of the lower Midwest. Ahead of the front, meridional (south-to-north) 5 kft winds over the Florida Peninsula are projected to reach the 90th percentile of climatology, ensuring the continued presence of warm/moist air and an introduction of some wind shear. ECMWF EFI values for CAPE exceed 0.8 on Monday, suggesting unusually high instability. Behind the boundary, cold advection will push below- normal temperatures and drier air into Central Florida beginning Tuesday. The 13/12Z grand ensemble remains in relatively strong agreement with pattern evolution through early next week.

As the polar jet retreats northward and an incredible 594+ dam H5 ridge overtakes a sizzling Sonoran Desert, guidance strongly suggests that a weak mid-level trough will get left behind between Florida and the Yucatan Peninsula by the middle of next week. A trough of low pressure may form over South Florida or the Florida Straits by around Thursday as the lingering mid-level feature interacts with a baroclinic zone. While a majority of members currently place much of its unsettled weather just south of the district, there is still low confidence in the forecast for mid to late next week.

Bottom line: a highly anomalous and, at times, historic weather pattern is forecast over parts of CONUS during the next week.
Increasing moisture and instability leads to an unsettled forecast through Monday ahead of a strong early-week cold front, followed by cooler conditions beginning Tuesday.

-------Sensible Weather & Impacts-------

Now - Tonight...

Of immediate concern is a low threat for heavy rain right along the Space & Treasure Coasts this morning. Hi-res guidance hints at this potential, with a reasonable worst-case scenario of isolated 3"+ amounts should the convection get going. The most likely scenario keeps much of the heavy rain offshore, but this will be worth monitoring closely.

As moisture increases, the chances for showers and a few storms will persist through the day (40-70%). Coverage should consolidate over the interior and perhaps even west central Florida by this evening before mostly dissipating tonight.

Expect partly sunny skies and temperatures a few degrees above normal today.

Sunday - Monday...

This should be the most active stretch of the forecast. Nearly all of the AI/ML convective outlooks suggest at least a 5-15% chance of severe hazards on Sunday and Monday.

On Sunday, an impulse aloft should combine with moderate instability and a diffuse sea breeze to spark 60-80% chances for showers and storms in the afternoon and evening. This activity should be moving generally north-northeastward, with the interior and I-4 corridor having the highest potential for storms. There remains a marginal (5-10%) risk for a few strong to severe storms on Sunday, with moist, warm air beneath a dry and cool middle troposphere. Shear looks relatively weak, but the setup seems favorable for strong wind gusts, a few up to 60 mph, and coin-sized hail. Repeated storms over urban and poorly drained locales may cause some minor flooding. The 13/18Z REFS suggested a reasonable high end of 3-4" rainfall totals (10% chance) with areal averages closer to 0.25-1".

The sharp cold front makes its final approach to the district on Monday afternoon. Moderate instability and somewhat more favorable shear are expected to blossom as the front moves over the area, leading to another round of showers and storms. Model proximity soundings suggest another low (but non-zero) risk of a few strong to severe storms on Monday; primary hazards should again be gusty winds to 50-60 mph and coin-sized hail. A tornado cannot be ruled out, though this is a secondary threat at this time.

High temperatures remain warm, in the low to mid-80s, both days. Monday looks quite breezy, with wind gusts up to 25-30 mph.

Remainder of Next Week...

Once the cold front exits the state Monday night, decidedly colder air will be felt in its wake. Most likely wind chills on Tuesday morning slip into the upper 30s from Daytona Beach to Leesburg, and highs on Tuesday currently have a 40-70% chance of failing to reach 60 degrees roughly near and northwest of I-4. Much of the interior and Volusia County should fall into the 40s on Wednesday morning, with low-mid 50s elsewhere. There is a 30-40% chance of reaching the upper 30s north of Leesburg to Ormond Beach.

Much of east central Florida looks dry on Tuesday. Confidence trails off thereafter as a mid-level trough lingers. While the highest coverage of rain from Wednesday through next Friday looks to reside over South Florida, statistical guidance still paints 20-40% rain chances over the Treasure Coast on Wednesday, expanding to areas southeast of I-4 on Thursday. The disturbance responsible for this activity should exit on Friday, with only low shower chances lingering at the coast.

High temps remain below normal on Wednesday/Thursday (upper 60s-low 70s) before moderating closer to normal on Friday (mid/upper 70s). There is a 60-80% chance of reaching 80 degrees once again by next Saturday.

MARINE
Issued at 207 AM EDT Sat Mar 14 2026

Poor to hazardous boating conditions continue in the Gulf Stream this morning. A diffuse front will lift northward over the next 24 hours, with winds slowly shifting toward the southeast by Sunday. Winds freshen out of the southwest on Monday ahead of a strong cold front, becoming northwesterly once it passes on Monday night. Unsettled weather is forecast at times through early next week, and boating conditions will worsen yet again from Monday into Tuesday.

Today, seas settling to 4 to 5 ft in the afternoon with ENE winds 10-15 KT. On Sunday, winds turn SE around 15 kt with sea 3-4 ft. Winds become southwesterly 15-25 kt on Monday, turning northwesterly 20-25 kt on Monday night. Seas build to 4-6 ft on Monday, then as high as 9 ft early Tuesday in the Gulf Stream behind the front.

AVIATION
(06Z TAFs)
Issued at 207 AM EDT Sat Mar 14 2026

Mainly VFR CIGs but ocnl MVFR CIGs in scattered SHRA lifting north across Treasure coast terminals overnight. Isold TSRA will be possible SUA-FPR. The SHRA will spread toward MLB/MCO/SFB/LEE where a VCSH is currently indicated in the respective TAFs. Some redevelopment of SHRA/TSRA appears most likely invof SUA-FPR aft 19Z this aftn. Winds ENE to E increasing 8-12 knots after sunrise, then decreasing and veering SE tonight.

PRELIMINARY POINT TEMPS/POPS
DAB 78 64 84 66 / 30 30 80 60 MCO 80 66 85 68 / 50 20 80 40 MLB 79 66 83 68 / 50 40 80 50 VRB 80 66 83 67 / 50 40 80 50 LEE 81 65 85 68 / 40 20 80 50 SFB 80 65 85 67 / 40 20 80 60 ORL 80 66 85 68 / 50 20 80 50 FPR 81 64 83 66 / 50 40 80 50

MLB WATCHES/WARNINGS/ADVISORIES
FL...None.
AM...None.