217 FXUS62 KMLB 151744 AFDMLBArea Forecast Discussion National Weather Service Melbourne FL 144 PM EDT Mon Sep 15 2025
...New AVIATION...
.KEY MESSAGES... Issued at 215 AM EDT Mon Sep 15 2025
- A high risk of life-threatening rip currents exists at area beaches today, entering the water is discouraged
- Low rain chances through Tuesday, coverage gradually increases from south to north mid to late week; locally heavy rainfall possible across the Treasure Coast Thursday and Friday
- Temperatures remain near to slightly below normal this week, especially across the south, where higher coverage of clouds and rain are forecast
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.PREVIOUS DISCUSSION... Issued at 215 AM EDT Mon Sep 15 2025
Today-Tonight...Early this morning, a low pressure system is situated over the Atlantic, east of the Carolinas. A weak surface boundary extends southwestward from the low, remaining nearly stationary over the Bahamas and Florida Straits. 500mb RAP analysis indicates a broad area of low pressure extending from northeast Florida to the Outer Banks. Drier air, closer to the 10th-25th percentile for this point in September, is in place over much of central and northern Florida. Dew points have fallen into the 60s, so temperatures in the 70s do not feel quite as muggy stepping out the door.
Temperatures are forecast to climb back toward mid-September normals (upper 80s/near 90) this afternoon under a partly cloudy sky. Forecast soundings stay rather dry but show a very modest increase in moisture around 850mb later in the day. Thus, isolated showers are possible, mainly from Orlando southward. Marginally supportive MLCAPE values will be pinned along the coast (Melbourne southward) and around Lake Okeechobee, so a slight chance for a storm should stay confined to those locations. For many, it will be a dry and seasonably warm day, followed by temperatures in the 70s tonight (upper 60s north of I-4).
Tuesday-Wednesday...A mid-upper level low is cut off from the northern stream by mid week and is gradually absorbed into an upstream trough by late Wednesday into Thursday. Until then, its surface low reflection over the Atlantic will continue north- northwestward, eventually moving onshore near the North Carolina and southeast Virginia coast. By Wednesday, this low center (well north of the local area) is progged to help re-establish/bring a surface boundary northward over the Florida Peninsula. Onshore flow persists as a little more moisture spreads northward, mainly Wednesday and beyond. Tuesday`s rain chances look similar to today`s, with the focus for isolated to scattered showers from Osceola/southern Brevard County southward (limited thunder). Guidance depicts a moisture gradient centered over the area Wednesday (PW 1.4" north to 2"+ south). Any threat for locally heavy rainfall will likely be confined to southern Martin County and points south Wednesday afternoon. Forecast highs trend near to slightly below normal Tuesday with below normal temperatures (mid 80s) Wednesday across Okeechobee County and much of the immediate coast.
Thursday-Sunday...As the H5 Mid Atlantic low dissipates and joins a deepening trough over the northeast Thursday-Friday, we end up underneath broad troughing over the Midwest/Tennessee Valley next weekend. Deep moisture transport looks to be most persistent southeast of the Orlando area, pooled at times along the quasi- stationary surface front, with comparably drier air (1.5"-1.7" PW) situated farther inland and northwest of the boundary. For southern portions of the Treasure Coast still in D2 (Severe Drought), high rain chances through at least Thursday and Friday could help put a dent in drought conditions. Multi-run 24-hour QPF trends across the EC/EC-AIFS/GFS ensemble suites are focused on heavier rainfall potential Thursday into early Friday, especially from Fort Pierce southward to Stuart. NBE 72-hr probabilities of greater than 2" Wednesday A.M. through Saturday A.M. are around 20-30%, which is notable at this time range. Despite the dry antecedent conditions, portions of the Treasure Coast could see enough rain in a short enough span of time to create localized flooding concerns (especially Thursday and Friday).
Farther north, forecast rain amounts ranging from a few hundredths to 1-2" are possible, with higher values focused along the coast from Cape Canaveral southward. Rain chances will last into the weekend areawide but the threat for locally heavy rainfall is a bit more in question due to model discrepancies. Temperatures during the period will remain near to slightly below normal, especially where added cloud cover prohibits more efficient daytime heating.
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.MARINE... Issued at 215 AM EDT Mon Sep 15 2025
North-northeasterly flow becomes more east-northeasterly mid to late week. Wind speeds generally 10-12 kt thru Wed. (locally 15 kt at the coast) increase up to 15 kt across the waters Thu. and Fri. Boating conditions remain poor today (small craft should exercise caution) over the Gulf Stream due to 6 ft waves, but gradual improvements are forecast by Tue. Wave heights generally remain 3-5 ft Tue., decreasing to 2-4 ft Wed.-Fri. Low rain chances will be largely confined to the Gulf Stream and southern Treasure Coast waters through Wednesday until deeper moisture brings higher rain and isolated lightning storm chances late week.
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.AVIATION... (18Z TAFs) Issued at 131 PM EDT Mon Sep 15 2025
Dry air has pushed southward across the peninsula today, leaving very limited moisture for areas north of KMCO. To the south, however, PWAT values still hover above 1.50", thus isolated showers have begun to initialize along the sea breeze south of KMLB. Have maintained VCSH from 18-00Z for the southern coast; elsewhere will remain dry thru the TAF period. North winds around 5-10 knots become variable overnight, then northeast by 15Z tomorrow. Similar pattern tomorrow, although slightly higher rain chances across the south. Prevailing VFR.
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.PRELIMINARY POINT TEMPS/POPS... DAB 70 85 71 86 / 0 10 0 10 MCO 71 90 71 89 / 10 20 10 20 MLB 74 87 75 86 / 10 20 20 30 VRB 73 88 74 87 / 10 30 30 50 LEE 69 89 70 89 / 0 10 0 10 SFB 70 88 71 88 / 0 10 0 20 ORL 71 89 72 89 / 0 20 10 20 FPR 73 88 73 86 / 10 30 30 50
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.MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. &&
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DISCUSSION...Schaper AVIATION...Schaper
NWS MLB Office Area Forecast Discussion