Area Forecast Discussion
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
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606 FXUS62 KMLB 210133 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 933 PM EDT Thu Jun 20 2024 ...New UPDATE... .UPDATE... (Through Friday) Issued at 933 PM EDT Thu Jun 20 2024 KEY MESSAGES... - Low pressure 200 miles east of Cape Canaveral has a 50% chance of tropical development over the next 18 hours as it approaches North Florida. - Scattered to numerous showers and isolated lightning storms overnight north of Melbourne to Kissimmee. Shower coverage on Friday is expected to be highest north of Orlando. - Hazardous beach and boating conditions continue tonight, with large waves and a high risk of deadly rip currents. - Increasing heat and humidity near and south of Orlando on Friday, with max heat index readings as high as 100-105F. Invest 92L, a weak low pressure system, is approaching Florida`s Atlantic coast tonight. A surge of deep moisture is moving onshore now from Melbourne northward, with PW`s sharply increasing to around 2.50" according to MIMIC-TPW data. This is above the max moving average, and approaching record daily values for late June. Bands of showers are increasing just off the coast. Through the overnight, shower chances increase to around 30% along the Treasure Coast, 40-50% for Melbourne to Orlando, and 60-80% from Titusville to Daytona Beach. Mainly north of Melbourne, there is a 20-40% chance of receiving more than an inch of rain through mid- morning Friday, and a lower (approximately 10%) chance of spotty 2 inch amounts where repeated rains occur. As the low approaches northeast Florida, we will begin to reside under a surface trough, allowing the pressure gradient to relax overnight into Friday morning. Expect winds to become lighter and more variable. The exception to this will be in the vicinity of heavier showers and any isolated storms, especially along the coast, where gusts to 25-35 mph will be attainable. Breaking 5-7 FT surf and a high risk of rip currents continue at our area beaches overnight. Friday`s forecast is somewhat challenging as the steering flow begins to collapse around 92L. The plume of deep moisture will slowly move northwestward, and modestly drier air will reside immediately to its south. Guidance still disagrees on how quickly this plume exits our area. At this time, showers appear likely (55-65%) north of Orlando in the morning, becoming more scattered (30-50%) near Orlando and isolated to dry (<20%) south from there. Then, we will reintroduce a 30% chance of storms for much of the area late in the afternoon as some moisture tries to sneak back in from the south. While sunshine will break out for our southern communities, clouds may linger along and north of I-4. Highs on Friday will be dependent on the clearing trend from south to north. High confidence in low/mid 90s over South-Central Florida (Osceola/Okeechobee) and the interior Treasure Coast, and upper 80s/low 90s Space and Treasure Coasts. Along and north of I-4 where clouds may linger, went with a range from 85-92F, "coolest" near Daytona Beach. With the high humidity, peak heat index readings from 95-105F are expected, highest south of Orlando. && .PREVIOUS DISCUSSION... (Saturday - Wednesday) Issued at 300 PM EDT Thu Jun 20 2024 Saturday-Wednesday...Saturday marks the beginning of increasing rain chances this weekend and into next week. Upper level ridging stays in place across the southern tier of the U.S., weakly influencing the overall pattern here in Florida. H500 falls across the southeast and Mid Atlantic are expected Sunday into Monday as a low pressure system moves across the Great Lakes region. Surface flow will remain southerly, backing southeast during the afternoon as the sea breeze forms. Light flow becomes increasingly SSW through midweek next week. With PW around 2"+ through much of this period, expect at least scattered to perhaps numerous showers and storms each afternoon and evening as sea breeze and storm- scale boundary collisions occur over the peninsula. PoPs go from 50-55 percent Saturday up to 60-70 percent later in the weekend and next week. The NBM remains a bit aggressive so forecast values still remain under that and some of the other medium range guidance. Regardless, this stretch of days could provide some additional, much needed rain for parts of the area. Temperatures through the extended stay warm, generally in the low 90s, with heat indices approaching 100-107. Nighttime temperatures will stay in the mid to upper 70s. && .AVIATION... (00Z TAFs) Issued at 725 PM EDT Thu Jun 20 2024 IMPACT: - Increasing shower chances overnight (40-70%) with low (20%) chance of storms for DAB/SFB/TIX/MCO/LEE, along with occasionally reduced CIGs (MVFR). A rather complicated forecast over the next 12-24 HR. Low pressure arriving from the Atlantic overnight will bring periods of showers to areas near and north of ISM/MCO/MLB. CIGs may go into prevailing MVFR between 08-12Z over some of these areas (20-40% probability) with only a 10% chance of reaching IFR. Winds should actually lessen overnight into Friday morning, becoming variable as the disturbance moves nearby. Exception to this is the potential for brief gusts to 25 KT in heavier showers. Showers will be less frequent for the Treasure Coast terminals overnight. On Friday, showers gradually diminish over our Greater Orlando/Daytona terminals by late morning/afternoon as winds try to turn from SSE to SE 5-15 KT. && .MARINE... Issued at 300 PM EDT Thu Jun 20 2024 Tonight...Hazardous marine conditions remain with a Small Craft Advisory in effect. Breezy to gusty northeast winds persist as an approaching low pressure system brings rain and isolated lightning storms through Friday morning. Seas build up to 9 feet offshore, mainly north of Sebastian Inlet. Closer to the coast seas 5-7 ft are expected. Winds begin to subside from midnight onward as the Atlantic disturbance (AL92) begins to lift northwestward. Friday-Monday (modified previous)...By Friday morning, winds are forecast to be southeasterly. Seas subside through the day, becoming 4-6 ft by the afternoon. Scattered showers with a few embedded lightning storms are forecast through at least Friday morning, especially near and north of Cape Canaveral. Improving boating conditions this weekend into early next week, with southeasterly to southerly winds remaining under 15 kts. Seas 3-4 ft becoming 2-3 ft through the period. However, greater daily shower and thunderstorm coverage is expected, especially early next week, with increasing chances for offshore-moving convection each afternoon and evening. && .PRELIMINARY POINT TEMPS/POPS... DAB 75 87 77 90 / 70 70 30 50 MCO 75 91 77 92 / 50 50 20 60 MLB 75 89 78 90 / 40 30 20 50 VRB 74 88 77 90 / 30 30 30 50 LEE 76 90 78 94 / 50 60 20 60 SFB 75 90 77 93 / 50 50 20 60 ORL 75 91 77 93 / 50 50 20 60 FPR 73 89 76 90 / 30 30 30 50 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...High Surf Advisory until 4 AM EDT Friday for FLZ141-154-159-164- 347-447-647-747. AM...Small Craft Advisory until 4 AM EDT Friday for AMZ550-552-555- 575. Small Craft Advisory until 11 AM EDT Friday for AMZ570-572. && $$ UPDATE...Heil AVIATION...Heil