Area Forecast Discussion
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
515 FXUS62 KMLB 060912 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 512 AM EDT Mon May 6 2024 .DISCUSSION... Issued at 424 AM EDT Mon May 6 2024 Key Messages: -Decreasing Rain Chances, but Isolated Showers and Lightning Storms Remain Possible This Afternoon and Evening. -Early season heat wave mid to late week with near record high temperatures. Currently...Mostly quiet across east central Florida this morning. Satellite and radar imagery show a few convergence lines over the Atlantic waters that have been occasionally producing showers, a couple of which have moved onshore. A gentle overnight breeze has prevented fog for the most part this morning, but there remains potential for smoke/fog in the vicinity of a wildfire that developed near SR-70 close to the Okeechobee and St. Lucie county borders yesterday. If driving through this area, be alert and ready to slow down if you encounter visibility reductions due to settling smoke/fog. Today-Tonight...Broad mid-upper level ridging aloft extends from the eastern Pacific off the coast of Mexico, across the Gulf, and into the southeastern US, as the shortwave ridge over Florida ejects to the east. At the surface, high pressure draped along the eastern seaboard and western Atlantic begins to pivot toward the subtropics, with the western periphery anchored over Florida, keeping us under the high`s influence. As the high shifts, the ridge axis will begin to drift from Central to South Florida, turning low level flow from southeasterly this morning to southerly late tonight. With the southeasterly flow and adequate low-level moisture over the Atlantic waters, onshore moving showers will be possible along the coast, mainly from the Cape south this morning. The east coast sea breeze will develop in the afternoon and push inland as usual, increasing winds to 10-15 mph with gusts up to 20 mph after passing through. Afternoon highs similar to yesterday in the U80s-90 inland and L- M80s along the coast, but wouldn`t be surprised a few spots made it to the L90s inland and U80s along the I-95 corridor. Overnight lows around 70 should be a little better behaved as flow becomes more southerly (onshore flow staying up late kept a few spots in the M70s the last couple nights). Isolated onshore moving showers will be possible along the southern coast again late tonight. As for afternoon lightning storms, still have some higher moisture lingering around the northern half of ECFL, with models calling for PWATs 1.4-1.5" (around the 75th climatological percentile) decreasing to 1.1-1.3" south near Stuart and Lake Okeechobee, confirmed by GOES imagery early this morning. Since the upper level support has departed, subsidence is increasing, and dry upper levels remain hostile to updrafts, PoPs for showers and storms along and ahead of the sea breeze just 20 pct for most, and only topping out at 30 pct along and north of I-4, where moisture is highest and in proximity of the sea breeze collision later in the evening. 500mb temperatures -8C to -9C and SBCAPE 1,000-1,500J/kg will be sufficient to support isolated lightning storms capable of occasional cloud to ground lightning, gusty winds, and locally heavy downpours. Highest chances for lightning storms will be along and north of I-4, decreasing to all but zero down south. Steering flow remains weak, so storm motion will be slow and erratic again, which could lead to minor flooding if a heavier shower or storm becomes stationary. Tue-Thu...A mid-level (500 mb) ridge builds over the FL peninsula and the resulting subsidence will increase the hot and dry conditions. In the low levels, the Atlc ridge axis will slip southward across the area causing local winds to veer more S-SW. Over the interior, max temperatures in the low to mid 90s Tue will become widespread mid 90s Wed-Thu with some upper 90s possible Thu. Thu now looks like the hottest day over the north interior (Orlando metro). Along the immediate coast (barrier islands), daily sea breezes will hold max temps to the mid 80s Tue, then upper 80s/near 90 Wed-Thu as the sea breeze becomes progressively delayed by increasing offshore flow. But inland portions of the coastal counties (west of I-95) will reach the mid 90s Wed-Thu. Sea breeze collision over the interior late Tue will produce the best chance (20-30%) for showers/storms. Rain chances look too sparse to mention Wed-Thu under mostly sunny skies. Peak heat indices upper 90s/near 100 with wet bulb globe temps indicating a Moderate to High heat risk. Fri-Sun...Deterministic model guidance show a weak frontal boundary crossing the area Friday night with isolated to scattered storms ahead of the front reaching our northern counties Fri aftn. So have bumped up rain chances Orlando northward but not as high as the NBM and kept the south half of FA dry Fri. The increase in clouds and rain chances should temper the max temps a couple/few degrees but still hot in the low to mid 90s. But Fri looks like the hottest day for southern sections, esp the coast as the sea breeze will struggle to develop due to breezy/gusty offshore winds. Widespread mid 90s along the coast south of the Cape which will get close to record highs there. For the weekend, will lean toward the ECMWF which shows the weak front stalling across south FL with a second front pushing into the deep South Sunday as upper troughing develops over the eastern CONUS. Some deeper moisture should advect in from the west ahead of this second front and produce an opportunity for scattered showers but also lightning storms both Sat-Sun. Max temps will range from the upper 80s across the north and lower 90s south. && .AVIATION... (06Z TAFs) Issued at 424 AM EDT Mon May 6 2024 VFR conditions prevail at coastal terminals, and mainly VFR conditions at inland terminals through the TAF period. ISO onshore moving SH possible INVOF KTIX-KSUA this morning once again, but confidence too low for prevailing VC mention. Lower chances for diurnal TS/SH today, so no TEMPOs, and only KLEE carrying VCTS 19Z- 02Z in the 06Z package. KMCO/KSFB/KISM limited to VCSH 19Z-00Z due to low confidence of impacts at this time. Afternoon TS/SH expected to remain west of the coastal terminals. VFR conditions prevail overnight. Winds SE 5-10 kts this morning shift to ESE 10-15 kts with gusts up to 20 kts in the afternoon behind the ECSB, then settle to Srly 5-10 kts overnight. && .MARINE... Issued at 424 AM EDT Mon May 6 2024 Today-Tonight...Generally favorable boating conditions. High pressure draped across the eastern seaboard and the western Atlantic begins to pivot southeast towards the subtropics, with the western periphery anchored near 30N lat. Winds SSE-SE 10-15 kts this morning back a bit more easterly while increasing to around 15 kts with gusts to 20 kts in the afternoon as the sea breeze develops, then veer to SSW-SSE around 10 kts late tonight. Seas 2-3 ft. Isolated showers and lightning storms possible, especially across the inland lakes along and north of I-4 in the late afternoon and evening. Tue-Fri...Low level ridge axis will slip southward across the area, reaching south FL Thu-Fri. This will promote a South wind flow to start Tue morning, veering SW once the ridge axis passes by Wed-Thu. Daily sea breezes of SE 10-15 knots will develop near the coast each aftn but onset will become gradually delayed each day due to increasing offshore flow. By Fri, the offshore (West southwest) flow may be strong enough to hold off the sea breeze altogether. Seas of 2-3 ft persist through the period, building to 4 feet late Wed-Wed night as pressure gradient should support 15-20 knots. && .FIRE WEATHER... Issued at 424 AM EDT Mon May 6 2024 Today...Decreasing moisture will result in min RHs dropping to around 40 pct across the western interior this afternoon. Winds SE 5-10 mph this morning back to ESE and increase to 10-15 mph with gusts up to 20 mph this afternoon behind the sea breeze. Isolated lightning storms possible, mainly along and north of I-4. High pressure ridge axis will gradually shift south across central Florida this week. The east coast sea breeze will develop and push inland Tuesday with a sea breeze collision over the interior in the late afternoon, resulting in isolated lightning storms. Winds will increase to 12-15 KT behind the sea breeze with gusts up to 20 KT possible. Min RH values will be near 40 percent over the interior and hold between 50 and 55 percent along the coast Tuesday. Fire weather conditions will become increasingly sensitive as temperatures increase into the mid 90s Wed-Fri with breezy/gusty west to southwest winds and min RH values 30-35 percent interior. Near Red Flag conditions are possible Thursday and Friday. && .PRELIMINARY POINT TEMPS/POPS... DAB 85 69 89 69 / 20 10 20 0 MCO 89 70 92 71 / 30 10 30 0 MLB 83 71 87 70 / 20 20 20 0 VRB 85 69 88 69 / 20 20 20 0 LEE 90 71 92 71 / 30 20 30 0 SFB 89 70 92 70 / 30 10 20 0 ORL 90 70 92 72 / 30 10 30 0 FPR 85 69 88 68 / 20 20 20 0 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ SHORT TERM...Haley LONG TERM...Kelly AVIATION...Haley