####018005678#### FXUS62 KCHS 041446 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1046 AM EDT Sat May 4 2024 .SYNOPSIS... Atlantic high pressure will remain across the Southeast U.S. through much of next week. && .NEAR TERM /THROUGH TONIGHT/... Convoluted pattern across the region this morning with a short- wave circulation moving northeastward into north-central Georgia and weak low-mid level troughing aligned through eastern Georgia into upstate South Carolina. Forcing with the wave aligned with lower level convergence has/is producing a solid narrow corridor of slow moving showers and thunderstorms in eastern Georgia into the Midlands...just edging into the far western part of the CWA. Convection does appear to be weakening as we transition into the daytime heating cycle. Meanwhile, showers (no lightning thus far) are expanding off the Atlantic into the South Carolina counties readily this morning, particularly the tri-county area. No surprise given the morning CHS sounding showing a moist low level air mass and nearly 500 J/Kg MLCAPE already in place, with minimal CINH. Short-wave trough will slowly pass through the region through the afternoon. Aforementioned corridor of showers/thunder just upstream will probably thin out to some degree over the next few hours. However, heating will generate 750-1000 J/Kg MLCAPE this afternoon and possibly a bit better along the inland advancing sea breeze...and minimal CINH. Additional showers and some thunderstorms are likely as we go through the afternoon with higher pops trending inland with the sea breeze push. Severe storms are unlikely. But given weak wind profiles and resultant slow moving convection, we will need to keep an eye on rainfall rates and amounts. Thunderstorm activity should gradually decrease this evening as the sea breeze pushes inland and temperatures begin to cool around sunset. The sfc pattern is expected to support light SSE winds through tonight. The light SSE winds combined with mostly cloudy sky conditions should keep temperatures in the upper 60s along the coast with mid 60s inland. The mid-level trough is forecast to swing east over the CWA late tonight. Guidance indicates that a band of moisture convergence will develop from the Gulf Stream northwest across the South Santee basin late tonight. Scattered showers and isolated thunderstorms will be featured in the forecast for late tonight over the SC waters and portions of Charleston and Berkeley Counties late tonight. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... A mid-level ridge will sit off the Southeast coast as passing waves of shortwave energy ripple across the region through the short term forecast period. High pressure will remain the primary feature at the surface. Convection will be a bit active Sunday and Monday with the presence of a weak shortwave aloft and deeper moisture - noted by PWATs around 1.5-1.7 inches. Coverage of showers/thunderstorms will be highest in the daytime when instability is maximized, but activity could linger into the late evening with some upper forcing present. The greatest POPs are focused in southeast South Carolina and away from the immediate coast each day owing to the juxtaposition of upper forcing and the inland moving sea breeze. Chances for showers/thunderstorms will be slightly less Tuesday as the deeper moisture and remnant shortwave energy moves off the Mid Atlantic coast. High temperatures will generally peak in the low to mid 80s Sunday, warming into the mid 80s Monday, then into the upper 80s Tuesday. Min temperatures both Sunday and Monday are only expected to drop to the mid/upper 60s, with locations along the beaches and Downtown Charleston in the lower 70s. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... Atlantic high pressure will persist through the majority of next week before a cold front approaches late next week. Rainfall chances are little to none as a ridge rebuilds overhead. This will cause temperatures to rise into the low/mid 90s through the remainder of next week, approaching record levels Wednesday and again Thursday. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... VFR conditions are expected to prevail at KCHS, KJZI, and KSAV through 12z Sunday. A few showers may pass near the KCHS and KJZI terminals this morning. This afternoon, shower and thunderstorm activity should mostly stay to the west of the terminals along a sea breeze. Winds should favor a south- southeast direction during the daylight hours, becoming light and variable late tonight. Extended Aviation Outlook: Brief flight restrictions are possible within isolated to scattered showers/thunderstorms through Tuesday. && .MARINE... The surface pattern will yield south-southeast winds between 5-10 kts today and tonight. Wave heights are forecast to favor values around 2 ft, with 3 ft seas possible beyond 40 nm late tonight. Sunday through Thursday: Atlantic high pressure will maintain relatively benign conditions over the local marine waters. Southerly winds in the morning will back slightly during the afternoon and evening hours nearly each day as the sea breeze develops. Winds will average 10-15 kt with seas 2-4 ft. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...Adam/NED SHORT TERM...BRM LONG TERM...BRM AVIATION...BRM/NED MARINE...BRM/NED ####018009586#### FXUS62 KMLB 041447 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 1047 AM EDT Sat May 4 2024 ...New UPDATE, AVIATION, MARINE... .UPDATE... Issued at 1046 AM EDT Sat May 4 2024 A few showers are ongoing across the Atlantic, as seen on the KMLB radar, with a few of these showers making it to the coast and as far inland as around I-95. Satellite and local observations show plenty of sunshine this morning, with some low and high level clouds streaming overhead. These showers are moving west to northwest around 5-10 mph. Light winds earlier this morning has increased to 8- 10 pm with temperatures in the upper 70s to low 80s as of 10 AM. High pressure dominating the region will keep winds onshore, with the east coast sea breeze forecast to form in the afternoon. Increasing moisture along with shortwave energy traversing through the area will support isolated to scattered showers and lightning storms to form along the sea breeze as it pushes inland this afternoon. The greatest potential for convection to form will be west of I-95, with the highest rain chances (PoP 30 percent) and storm chances occurring across the far western interior where the sea breeze collision is expected to occur. Main storm threats will be occasional to frequent lightning strikes, gusty winds, and locally heavy downpours. Additional showers will be possible this morning and into this afternoon along the Atlantic waters with some of the showers making it along the coast to around I-95. Onshore flow will increase to 10-12 mph behind the sea breeze today, with gusts up to 20 mph possible, especially along the coast. Another warm day is in store for east central Florida, with afternoon highs in the low to mid 80s along the coast and upper 80s to low 90s across the interior. Forecast remains on track with no major changes. && .AVIATION... (12Z TAFs) Issued at 1046 AM EDT Sat May 4 2024 VFR conditions through the TAF period. FEW/SCT025-035 and SCT250 this morning with FEW/SCT040-070 and SCT140-250 this afternoon. light onshore winds this morning will increase to around 10 KT by mid morning. The east coast sea breeze is expected to form this afternoon and push inland, increasing winds to around 12 KT behind the boundary, with gusts up to 20 KT possible. Showers and lightning storms will develop along the sea breeze today as it pushes inland, mainly west of I-95. Have included VCSH for all inland terminals starting at 18/19Z. Have not included TEMPOs at this time, but will take another look for the 18Z package. Will monitor and amend as necessary with VCSH for coastal sites. Winds will then decrease in the evening, becoming light once again overnight. && .MARINE... Issued at 1046 AM EDT Sat May 4 2024 Showers are ongoing across the Atlantic this morning, mainly from Cape Canaveral southward. Some of this activity is making it to the coast. Favorable boating conditions will continue today as high pressure remains in place. Onshore flow will persist, with speeds generally around 10 KT before increasing to 10-15 KT with the formation of the east coast sea breeze each afternoon. Winds will then decrease to 5-10 KT overnight. Seas 2-3ft. Isolated showers will continue, especially across the Treasure Coast waters this afternoon and into tonight. && .FIRE WEATHER... Issued at 428 AM EDT Sat May 4 2024 Today...Sensitive fire weather conditions continue across the interior before additional moisture moves in later this evening. Min RHs drop to 35-40 pct in and around southern Lake County and 40-45 pct across the rest of the interior. Light southeasterly winds become easterly and increase to 10-15 mph with gusts to 20 mph in the afternoon behind the east coast sea breeze. Isolated showers and lightning storms possible along the sea breeze, but highest chances well inland towards the western half of the peninsula. Substantial wetting rain is not expected. Increasing heat and slightly drier conditions next week will produce min RH values falling to around 35% for much of the area inland from the coast by mid-week. Isolated lightning storms will be possible this weekend into Monday mainly over the interior late day/early evening, with isolated to scattered showers near the coast in the mornings. However, widespread wetting rainfall is not forecast through the next 7 days, so further fuel drying is expected. Temperatures will gradually warm each day, reaching the mid 90s interior by Wed. && .PREVIOUS DISCUSSION... Issued at 428 AM EDT Sat May 4 2024 Key Messages: -A Few Showers and Lightning Storms Possible This Afternoon and Evening. -Increasing Heat Next Week With Highs Reaching Well Into the 90s Over the Interior. Today-Tonight...Increasing moisture plus a mid-level shortwave swinging through will support a few showers and lightning storms along the sea breeze as it moves inland through the afternoon and evening. Surface high pressure remains draped down the Atlantic seaboard, continuing southeasterly surface flow and favoring earlier development and quicker inland movement of the east coast sea breeze. Light southeasterly winds this morning become easterly 10-15 mph in the afternoon (closer to 10 mph across the western interior), with gust up to 20 mph especially along the coast. This will once again keep afternoon highs along the coastal corridor around normal in the to the L-M80s, but inland locations warm back up above normal to the U80s-90. Overnight lows settle back to the U60s-L70s. We'll see increasing coverage of showers over the Atlantic waters, especially in the early morning and overnight, as the environment becomes more favorable. Some of these showers could move onshore, supporting 20 pct PoPs along the Treasure Coast into Brevard County a bit through the morning. Afternoon showers and lightning storms will be possible along the sea breeze once it gets going, so have 20 pct PoPs west of I-95 starting at 2 PM, increasing to 30 pct across the interior at 5 PM. PoPs drop below 20 pct for most areas after 8 PM, but linger across the interior into the late evening. Overnight, 20 pct PoPs shift back to the coast for those onshore moving showers. Most of the additional moisture is forecast to arrive later in the afternoon (PWATs near Leesburg hold 1.2-1.3" until around 8 PM, then increase to 1.5-1.6") and be more abundant in the mid- levels initially, so overcoming dry air at the surface and aloft will be a significant hurdle for deep convection on the eastern half of the peninsula. But with a good enough oomph from the sea breeze, 500mb temperatures decreasing to -10C will be able to support lightning storms capable of at least occasional cloud to ground lightning, possibly frequent lightning, gusty winds, and brief heavy downpours. Best chances for lightning storms will be across the western interior in the late afternoon to evening. A Moderate Risk for dangerous rip currents continues at all central Florida Atlantic beaches. Always swim near a lifeguard, and never swim alone. Sunday-Monday...High pressure ridge axis is forecast to remain just north of the area and support an E-SE flow across the area. Isolated to scattered showers may push onshore in the morning along the coast, developing into lightning storms during the afternoon inland from the coast. A sea breeze collision is favored on the western side of the peninsula. Modest low level moisture will support PoPs between 25-40 percent Sunday. Lower coverage is forecast Monday as some drier air moves in around the southern periphery of the ridge. Have drawn up to 30 PoP from Orlando north and west in the afternoon, 20 percent or less elsewhere. Above normal temperatures are forecast with highs ranging the mid 80s along the coast and upper 80s/low 90s across the interior. Tue-Fri...A mid level (500 mb) ridge builds over the FL peninsula and the resulting subsidence will increase the hot and dry conditions. Temperatures warming through the period reaching the mid 90s as early as Tue across the interior becoming widespread mid 90s Wed-Fri. Along the immediate coast (barrier islands), daily sea breezes will hold max temps to the mid 80s Tue, then upper 80s Wed-Thu. But inland portions of the coastal counties (west of I 95) will reach the lower 90s. Friday looks like the hottest day as the ridge axis slips farther south and offshore (SW) flow dominates with a much delayed sea breeze. This should allow max temps to reach the low 90s even at the coast with widespread mid 90s mainland. Although dewpoints and humidities will not be oppressive due to drier air, wet bulb globe temps indicate a Moderate to High heat risk. && .PRELIMINARY POINT TEMPS/POPS... DAB 84 68 85 68 / 20 10 30 10 MCO 88 69 88 69 / 20 10 40 10 MLB 83 70 84 70 / 20 20 30 10 VRB 85 68 85 68 / 20 20 30 10 LEE 89 70 88 70 / 30 20 40 10 SFB 88 69 88 68 / 20 10 40 10 ORL 89 70 88 70 / 30 10 40 10 FPR 84 68 85 68 / 20 20 30 10 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ Watson/Sedlock