Area Forecast Discussion
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
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115 FXUS62 KMLB 032010 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 410 PM EDT Wed Jul 3 2024 .DISCUSSION... Issued at 400 PM EDT Wed Jul 3 2024 KEY MESSAGES: - An extended period of above-normal temperatures continues through this holiday weekend. Residents and visitors will need to take extra precautions to prevent heat-related illness. - Daily chances for showers and storms hold near 30% to 60% from today through the weekend. Overall, storm coverage will be near to below normal, lowest Friday and Saturday. ---------Synoptic Overview---------- Relatively flat upper ridging, characterized by H5 heights exceeding 590 dam, extends from California to the subtropical Atlantic. As a mid-latitude trough works through the Great Lakes by this weekend, the H5 high will sink toward North Florida and remain nearby through at least Monday. Hurricane Beryl continues to be steered beneath this ridge on a track WNW through the Caribbean Sea, well south of Florida. In the low levels, high pressure and relatively light background winds persist throughout the next week. The ridge axis will also sink slowly southward, reaching Central Florida late Saturday and then slipping toward the FL Straits by late Sunday or Monday. The daily sea breeze circulation will be unimpeded within this pattern. Near-normal tropospheric moisture will remain in place, except late Friday through early Sunday when somewhat drier air briefly filters in aloft. This overall pattern will continue to support scattered afternoon/ early evening storms and above-normal temperatures which will pose a Moderate to Major HeatRisk across Central Florida. -----Sensible Weather & Impacts----- Thru tonight...East coast sea breeze is pushing steadily inland this aftn propelled by outflow from convection along the boundary. Late morning Cape sounding continues to show deep moisture with precip water values of 2.1" and this is largely all below 700 mb. So very moist low levels will support intense rain cores. Boundary collisions between the sea breeze, lake breezes and storm outflows will produce the stronger storms through early evening over the interior. Some drier air in the mid levels will support gustier downburst winds than we have seen in recent days. Coastal communities will remain mostly dry. Thu...A weak backdoor front is forecast to settle south across central FL with weak low pressure offshore over the Atlc. A very weak pressure gradient will be in place though so the sea breeze will develop on schedule by late morning and push inland. Northerly steering flow should bring aftn storms south from north FL during the aftn and focus over the interior, or at least inland from the coast. Significant heat and humidity will persist with max temps in the low 90s coast and mid 90s inland. High dewpoints will produce peak heat indices 103-107. Residents and especially visitors not acclimated to such heat should take precautions if spending long durations outdoors. Stay well hydrated and take frequent breaks out of direct sun, such as shade or an air conditioned space. Friday - Weekend: (previous) Not a whole lot of change as we move forward in time. It`s going to stay hot (maybe even a degree or two hotter) and there remains a daily chance for a few storms. The upper high will reside very close to us this weekend. Its large- scale subsidence and warm mid-level temperatures (-3C to -4C at H5, above the maximum climatological moving average) will suppress sustained deep convection. PWAT values also briefly sneak below 2" from Friday through Saturday. The near-surface ridge axis will move southward through the weekend, veering the synoptic PBL flow more southerly by Sunday. This translates to roughly 30-50% storm chances Fri/Sat (lowest near the coast and highest far interior), increasing to 50-60% on Sunday as moisture values start creeping upward again. H85 T`s climb slightly this weekend to around +20C, so we would not be surprised if surface temperatures are also a degree or two hotter. Statistical guidance suggests at least a 40% chance of reaching 95 degrees near and northwest of I-4 each day. Combined with seasonably high humidity, peak heat indices should reach 102- 108F. Confidence in how hot our heat indices will get is somewhat challenged by an increase in interquartile dew point spread within the model suite. Two takeaways, 1) there is still a potential for portions of the area to reach Heat Advisory criteria, and 2) either way, the Moderate to Major HeatRisk will persist, indicating an unusually high potential for heat stress. Early Next Week: (previous) Deep-layer ridging is forecast to extend from the Bermuda High to the Gulf of Mexico. Meanwhile, a weakness in upper heights is indicated from the Midwest to Texas. Boundary-layer winds are forecast to hold southerly or even veer slightly SSW, and a slug of higher moisture extending north from a tropical wave over the N Caribbean may pass overhead. Thus, storm chances look a little higher on Monday. At least scattered storm chances (40-60%) will persist into the middle of next week, but confidence does drop off next Tue/Wed as the upper high holds close by and a SAL (Saharan air layer) may advance toward the state. Temperatures should continue to run near to above normal, with low/mid 90s by day and mid 70s at night. Heat indices will keep lurking at or just below the 108F advisory threshold. && .MARINE... Issued at 235 PM EDT Wed Jul 3 2024 A high pressure axis will hold north of Florida through Friday, leading to light daytime SE breezes up to 10 KT (locally enhanced at the coast during the afternoon). Winds become light SW late in the overnight hours. The high pressure axis will settle southward through the local Atlantic this weekend, with light (5-12 KT) S/SE winds by day turning offshore at night. Seas 2-3 FT through the period, with a light to moderate chop over the Intracoastal. A few showers or isolated storms are forecast during the overnight and early morning hours offshore, shifting closer to the coast in the late morning and early afternoon hours. && .AVIATION... (18Z TAFs) Issued at 143 PM EDT Wed Jul 3 2024 VCSH/VCTS along and ahead of the east coast sea breeze this afternoon, gradually clearing at the coastal terminals. TEMPOs included at MCO/ISM (21/23Z) and LEE (22/24Z) where there is the greatest confidence in TSRA impacts. Coverage of showers and storms across the interior are forecast to diminish after 02/03Z. South to southeast winds become east with the passage of the sea breeze, generally remaining around 10 kts or less. Light and variable winds tonight. && .PRELIMINARY POINT TEMPS/POPS... DAB 77 92 76 91 / 20 50 10 30 MCO 77 94 76 94 / 30 70 10 40 MLB 78 92 77 91 / 10 40 10 40 VRB 76 92 76 91 / 10 30 10 40 LEE 78 94 78 94 / 40 70 20 50 SFB 77 94 77 94 / 30 70 10 40 ORL 78 94 78 94 / 30 70 10 40 FPR 76 92 76 91 / 10 30 10 40 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ DISCUSSION...Kelly AVIATION...Law