Area NWS Forecast Discussion
000 FXUS62 KILM 151632 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 1232 PM EDT Sat Aug 15 2020 .SYNOPSIS... Occasional shower and thunderstorm activity will prevail through the weekend, as several boundaries interact along with a humid and unstable air mass in place. Slightly drier air is expected to move in Sunday night and Monday, before unsettled weather returns by mid week. && .UPDATE... Forecast on track. Made minor adjustment to cloud cover and pops but overall expect plenty of clouds today with intermittent showers and storms. Deep SW winds will guide all showers and storms off to the NE. Temps should reach between 85 and 90 most places. && .NEAR TERM /THROUGH SUNDAY/... Active weather over the next 36 hours with showers and thunderstorms along a low pressure system and a series of frontal boundaries near the area. Model atmospheric profiles indicate a very moist environment (sounding climatology of precipitable water above the 90th percentile) and moderately unstable air mass (MLCAPE values between 1000 and 2000 J/KG) capable of producing thunderstorms with heavy rainfall and some gusty winds. Main concerns would be ponding of water on roadways, as well as urban and small stream flooding of poor drainage and low lying areas. Rain amounts will be highly dependent on where individual thunderstorms track, but many locations will likely see at least 0.50" over the next 36 hours with chances of receiving between 1 and 2 inches with locally higher amounts possible. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... Seasonably nice weather in store for the short term period. Surface front will be exiting the area Sunday night, with decreasing from west to east after sunset. Dry air moves in behind the front as low level northerly flow develops. Have lowered pops some for Monday into the slight chance range, as any convection that manages to develop should remain isolated. With light winds and high temps in the mid to upper 80s range, expecting a nice day Monday. Lows around 70 Sunday and Monday nights, with some spots inland possibly reaching upper 60s Sunday night. && .LONG TERM /TUESDAY THROUGH FRIDAY/... Unsettled weather starts to creep back into the forecast on Tuesday. Mid level moisture begins moving back in as deep south- southwest flow develops over the area late Tuesday through end of the week. Combination of weak surface boundary in the vicinity and sea afternoon sea breeze, widely scattered storms possible Tuesday afternoon. Late Tuesday, an upper level trough will be digging into the lower MS Valley before setting up southwest of our area Wednesday through Friday. With upper ridge situated to the southeast, this will allow a few rounds of impulses to move across the southeast and keep high chance pops in the forecast each day for the back half of the week, with greatest chances inland and to the south. Have continued to keep pops lower than guidance, with slight trend upwards. Temps near normal for long term period. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... With PWATS over two inches, along with a low LFC, convection could fire at just about any time, best chance of course will be this afternoon and evening. Locally heavy rainfall, along with dangerous cloud to ground lightning are a good bet with brief gusty winds in the storms. Extended Outlook...Scattered to numerous showers and tstorms expected this weekend. Drier air may work its way briefly across the area late Sun into early next week with less thunderstorm activity and coverage possible. && .MARINE... Through Sunday.. Total seas between 2 and 3 feet for the next 36 hours - increasing up to 3 to 5 feet beyond 15 NM into Sunday. Wind waves out of the southwest at 4 to 6 seconds with southeast swell between 8 and 10 seconds with southwest winds between 10 and 15 kts with gusts up to 20 kts at times. Inexperienced mariners or those with smaller vessels may encounter periodic hazardous conditions if venturing out beyond 15 NM through Sunday afternoon. Sunday Night through Wednesday.. SW winds around 10 kts Sunday night ahead of approaching front will veer to northerly around 10 kts by Monday morning as front moves to the east. Variable winds around 5 kts Monday evening through Tuesday as pressure gradient relaxes. SSE flow 5-10 kts sets up Tuesday night through Wednesday as high pressure strengthens offshore. 3-4 ft seas Sunday night will be on the decline, with seas around 2-3 ft forecasted for Monday and holding steady through Wednesday. Seas combination of weakening S wind wave and a 1-3 ft SE swell, with weak SE swell from TS Josephine mixed in Tuesday into Wednesday. Thunderstorm coverage will be decreasing Sunday night, with slight chance Monday and Monday night over coastal waters before storm chances increase again late Tuesday through end of the week. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...ILM UPDATE...RGZ NEAR TERM...MCK SHORT TERM...VAO LONG TERM...VAO AVIATION...43 MARINE...MCK/VAO