Area Forecast Discussion
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
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047 FXUS62 KMLB 021415 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 1015 AM EDT Tue Jul 2 2024 .UPDATE... Issued at 1010 AM EDT Tue Jul 2 2024 Motion of cloud elements seen on GOES-16 hi res visible satellite imagery nicely trace out the location of the low level ridge axis which extends from the Atlc across the northern Bahamas (Great Abaco/Grand Bahama) and westward across the Treasure coast/Lake Okeechobee. A stationary frontal boundary is analyzed across south GA and into the Atlc and this boundary will gradually dissipate. The early morning Cape sounding shows considerable low level moisture which should produce an early cu field over land. The cloud lines over the Atlc are already bubbling with showers as they lift northward and this should transition to coastal sections shortly as the east coast sea breeze develops initially along the Treasure coast. The showers should develop into lightning storms early this afternoon just inland from the coast which will develop/propagate inland with the sea breeze. Some gusty outflows may push back to the coast and affect portions of the intracoastal waters. Focus for storms will shift inland during the afternoon with another late collision with the west coast sea breeze near Lake county around sunset. No significant changes/updates needed on winds/temps/pops for today. && .PREVIOUS DISCUSSION... Issued at 258 AM EDT Tue Jul 2 2024 KEY MESSAGES: - Temperatures will remain above normal, as warm as the mid 90s in some locations. The risk of heat stress will increase as we move from Independence Day and into the weekend. - Continued daily storm chances, ranging from 30-50% near the coast to 40-60% over the interior, including Greater Orlando. - Major Hurricane Beryl, the earliest hurricane to reach category 5 on record in the Atlantic Basin, is moving through the eastern Caribbean. Beryl, and its impacts, are still forecast to stay well south of Florida. ---------Synoptic Overview---------- Early this morning, deep-layer ridging is centered over the Red River Valley (TX/OK). A pair of troughs bookend this feature, one over the Northern Rockies and another exiting the Canadian Maritimes. The cold front approaching Florida has dissipated to our north, but it has left above-normal tropospheric moisture over the state. Over the next few days, the mid-level ridge will flatten, with its axis roughly along the I-10 corridor from coast to coast. This will hinder significant northward movement for Hurricane Beryl as it churns through the Caribbean Sea. More information on this powerful storm can be found at hurricanes.gov. By this weekend, ensemble guidance has trended somewhat deeper with a trough digging across the Upper Midwest, which may flatten the ridge even further. However, H5 heights are predicted to exceed the 90th percentile of climatology (well above normal) through the entire forecast period locally. Less than 40 meters differentiated the 01/12Z clusters over Florida, indicating excellent large-scale model agreement. Near the surface, the ridge axis will begin lifting north over the next 24 hours, then remain north of the district through early Friday. This weekend, it will shift once again closer to Central/South Florida. Overall, no significant changes were required from the previous forecast package. There will be a daily chance of showers and storms, ranging from 30-50% near the coast to 40-60% over the interior and Greater Orlando area. Heat-related impacts are still expected to increase by this weekend. -----Sensible Weather & Impacts----- Today & Tonight: Light SSE flow today will allow another healthy sea breeze circulation. 0-3 KM mixing ratios remain well above normal, around 13 g/kg, indicating a very moist boundary layer. Expect widely scattered storms to develop along the advancing sea breeze near and west of I-95 early in the afternoon, with a potential sea breeze collision near / west of Orlando in the early evening hours. Overall, storm chances range from 40-50% near the coast to 60% over the interior and Greater Orlando. Gusty winds to 45 mph, frequent lightning, and locally heavy rain from 1-3" are the potential threats from today`s storms. Highs should reach 90-93F near the coast and 92-95F over the interior. Similar to yesterday, peak heat indices should climb to 102-107F. Lows overnight will fall to the mid 70s, except upper 70s around urban Orlando and the barrier islands. Wednesday - Friday: During this timeframe, including Independence Day, the near-surface ridge axis will get a kick north of here, allowing light SE PBL winds. The embedded sea breeze will propagate inland each day, and a collision with the Gulf breeze should occur west of Orlando. Held onto likely rain/storm chances (~60%) near and west of Orlando on Wednesday as H5 T`s and available moisture are somewhat more favorable for convection, lessening to around 40% along the coast. For the Fourth of July & Friday, H5 T`s jump closer to climatological maxima as heights build. With a slight nudge down in total moisture, we yield no more than 30-50% storm chances, once again highest well inland. Temperatures remain hot but fairly steady. Low/mid 90s are forecast, with mid/upper 70s at night. There are some indications that the boundary layer may become slightly less humid, conceivably helping dew points to mix down to the low 70s in the afternoon hours. We will go with peak heat indices 101-107F, just below Heat Advisory criteria. Nonetheless, this still exhibits a Moderate to locally Major HeatRisk; those celebrating the holiday outdoors should take precautions to beat the heat, such as staying well-hydrated and seeking breaks in the shade, A/C, or pool. Next Weekend & Beyond: As the upper ridge flattens out, the thermal ridge will also sink closer to our latitude this weekend, characterized by H85 T`s approaching +20C. Combined with seasonably high dew points, oppressive heat and humidity remain the #1 weather concern this weekend. Statistical guidance continues to suggest fairly widespread mid 90s over all but the immediate coast (low 90s) from Saturday through Monday. Overnight low temps will struggle to drop much below 80F in urban Orlando and remain 4-7F above normal for all locales. Peak heat index readings will nudge a couple of degrees warmer, perhaps reaching into our Heat Advisory territory (>= 108F) especially near and north of Greater Orlando. As the HeatRisk enters the Major range for more of us, it will be important to find ways to cool off and stay hydrated each afternoon. H5 temperatures will hang out around near or over the 99th percentile of climatology through the weekend, keeping mid-level lapse rates poor and likely stifling sustained deep convection. However, near-normal total moisture and above-normal 0-3 KM mixing ratios suggest that the daily sea breeze and late-day collision should be enough to spark widely scattered storms. Areal coverage should peak 40-50% each day, perhaps as high as 60% over the far interior. && .AVIATION... (12Z TAFs) Issued at 740 AM EDT Tue Jul 2 2024 Light southerly flow increases after 15z, backing SSE behind the ECSB after 17z. Isolated TSRA is forecast to form along the inland-moving breeze this afternoon, increasing in coverage from FPR/VRB to MCO/ISM, eventually reaching LEE after 22z. Brief MVFR/IFR conditions are possible where heavier TSRA occurs at any of the terminals. Activity will diminish after 02z Wed leaving behind light winds and gradually clearing conditions. && .MARINE... Issued at 258 AM EDT Tue Jul 2 2024 Today-Saturday... The surface high pressure axis will lift from near Central Florida today to the north of the local waters through at least early Friday. Light SSE winds (5-12 KT) turn more to the SE through mid and late week, as a result. The daily sea breeze circulation will locally enhance winds near the coast each afternoon before veering offshore and becoming light overnight. Seas 2 FT or less today, building slightly to 2-3 FT for the remainder of the week. A few showers and storms are forecast, especially during the overnight hours offshore and nearshore during the morning and early afternoon. However, a lot of dry weather is expected and overall favorable conditions will persist for both offshore and inshore boaters. && .PRELIMINARY POINT TEMPS/POPS... DAB 93 77 92 76 / 50 30 40 20 MCO 93 77 93 76 / 60 40 60 10 MLB 91 78 91 78 / 50 20 40 10 VRB 91 76 91 76 / 50 20 40 10 LEE 93 78 94 78 / 60 60 60 30 SFB 94 77 93 76 / 60 40 60 20 ORL 94 78 94 77 / 60 50 60 20 FPR 91 76 91 76 / 50 20 40 10 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ UPDATE...Kelly AVIATION...Schaper