Area Forecast Discussion
Issued by NWS Wilmington, NC
Issued by NWS Wilmington, NC
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243 FXUS62 KILM 041053 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 653 AM EDT Thu Jul 4 2024 .SYNOPSIS... High pressure will move offshore bringing warmer and more humid air to the Carolinas. Daytime heat indices could exceed 105 degrees beginning Friday. Thunderstorm chances will increase this weekend into early next week as a cold front stalls inland. && .UPDATE... No major changes coming down the track going into the 7 AM EDT update. Updated 12Z TAF discussion found below. && .NEAR TERM /THROUGH TONIGHT/... Latest surface analysis shows broad high pressure that extends up and down the entire eastern seaboard. The old frontal boundary in SC Lowcountry is still hanging on, but has made a slight northward push into the Sea Islands of Beaufort County, SC. Meanwhile, the anticyclone continues to spin over the Deep South. Surface high pressure moves offshore today, which increases the onshore flow across the area. Subsidence keeps rain chances at bay, with a stout inversion noted at around 700mb. The bad news is that heat and humidity is on the rise, and heat indices will hit the triple digits today for the first time since last weekend. We don`t quite hit Heat Advisory criteria (heat index of 105-109 degrees for 2+ hours), but it doesn`t necessarily matter. Keep up the water intake, wear light clothing, and limit the outdoor activities. Stay frosty. Lows tonight in the mid-to-upper 70s for most. Some of the typical cool spots may try to dip down into the upper 60s. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... Highlights: *Unseasonably hot and humid through the period with Heat Advisories likely and possibly also Excessive Heat Warnings Confidence: *Moderate to High Details: Main concern this period is the excessive heat and humidity as an unusually warm air mass under deep high pressure prevails. This will generally keep rain chances limited until possibly Saturday afternoon across inland areas where moisture/forcing will be a bit more favorable. Fortunately, the severe storm threat appears pretty low given the lack of deep layer shear. However, minor flooding is probably more of a threat given the potential of heavy rainfall given the plentiful moisture (PWAT >2") and weak deep layer flow. Temps should be above normal through the period with highs mostly in the mid to upper 90s and lows mainly in the mid to upper 70s. Heat indices should peak mostly below Excessive Heat Warning criteria (110 degrees) Friday with Heat Advisories most likely away from the immediate coast. On Saturday heat indices should be similar despite possibly lower temps since dewpoints should be a bit higher. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... Highlights: *Dangerous heat/humidity possible through the period Confidence: *Moderate Details: An upper low offshore early in the week could help weaken the upper ridge a bit but generally looks like the ridge will remain in place. At the surface, an approaching cold front should lose steam as it heads our way early in the week but could help increase rain chances a bit. Although can`t rule out a few severe storms through the period, the bigger concern will likely continue to be the heavy rain and minor flood potential. Models currently suggest some decent rain potential this period, especially inland where drought conditions are the worse. Although temps will be greatly dependent on the rain/cloud coverage we should have at least a slight risk for Heat Advisory potential each day, especially away from the immediate coastal areas. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... VFR throughout the 12Z TAF period. There are some observations of FEW to SCT stratocumulus at 1900-3000ft, but that shouldn`t equate to any MVFR ceilings, and if it does, it will be very brief. Light and variable winds should persist through the AM hours, until a SSE seabreeze pushes inland early this afternoon. Light SSW breeze towards the end of the TAF period. Extended Outlook...VFR through the end of the week outside of the potential for morning fog and stratus. Slight chance of flight restrictions this weekend and into early next week as chances for convection return. && .MARINE... Through Tonight...Southeasterly winds become SSW by tonight. Sustained speeds at 5-10kts to start, and then kick up to 10-15kts this afternoon and evening. Seas linger at 1-3ft, with an easterly swell at 6-7 seconds, and then long period southeasterly swells at 12-14 seconds (from Hurricane Beryl). Friday through Monday...Atlantic high pressure will prevail with a cold front likely stalling out inland early next week. Although winds will be elevated at times, mainly each afternoon due to the sea breeze, they should mostly stay 20 kt or less. Seas will stay 4 ft or less with wave periods diminishing through the period as the SE swells subside. Thus, not expecting any Small Craft Advisories. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...None. SC...None. MARINE...None. && $$ SYNOPSIS...ILM UPDATE...IGB NEAR TERM...IGB SHORT TERM...RJB LONG TERM...RJB AVIATION...IGB MARINE...RJB/IGB