Marine Weather and Tide Forecast for Irmo, SC

NEAR TERM /THROUGH TONIGHT/
Key Message(s):

- Warm day in store with above average high temperatures.

The forecast remains largely on track this morning as riding and strong surface high pressure remain in place. Both of these features may shift slightly southeastward into tonight but overall, this will lead to little to no change in the forecast.
850 mb temperatures are already reaching 14C per mesoanalysis while we keep some thin cirrus over the region and some scattered to broken low clouds. More scattered cumulus is expected this afternoon as southwesterly winds bring temperatures into the upper 80s across the FA and PWAT's remain near to just under 1". As 12z model guidance continues to come in, there continues to be a couple high res model runs that bring decaying convection just north of the far northern Midlands and Pee Dee region but the general trend amongst all these runs is this activity stays just north of the FA so I have continued the dry forecast. Tonight, mostly clear skies and light to calm winds are expected as overnight lows fall into the upper 50s to low 60s again

SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/
Key Message(s):

- Another warm day in store with dry weather likely

The axis of an upper ridge will be just east of the FA on Thursday as a shortwave lifts into the Ohio Valley. Southerly flow and ridging aloft will favor well above normal temperatures. Highs will be in the upper 80s but dewpoints should mix down into the 50s in the afternoon so not quite the summertime feel yet. Shortwave activity will lift north of the area as they work over the ridge. PWAT values are also only around 1 inch so convection is unlikely. Lows in the low to mid 60s as increasing cloud cover help promote mild temps.

LONG TERM /FRIDAY THROUGH TUESDAY/
Key Message(s):

- Scattered showers and storms possible late Fri and Sat

The main change in the long term is the noticeably slower progression of the frontal system through the region. Overall this will work to keep rain chances in the forecast for Sunday with a slight chance of lingering showers for Monday.

An upper level trough will move into the eastern US late this week and over the weekend as ridging moves further offshore. A surface low will lift into the Northeast on Friday as the associated cold front slowly drags into the Southeast. A pre- frontal trough/convective outflow could work into the forecast area Friday followed by the main frontal passage over the weekend. Although moisture is somewhat limited (PWATs only around 1.25" and NAEFS IVT at or below the 90th percentile) so widespread significant rainfall seems unlikely. What is more likely is periods of scattered showers and thunderstorms triggered by upstream convective outflow and diurnal heating.
Lapse rates on Friday are not overly steep leading to a limited threat of severe weather but it's not out of the questing that a few storms produce damaging winds or small hail. Consistent shortwave activity may allow showers to continue into the night, especially Saturday night as the front works through the area.
Lingering moisture due to the slower progression of the front could allow for some showers on Sunday but chances are low. Dry weather is likely for the remainder of the long term with temperatures much closer to normal behind the front.

AVIATION /14Z WEDNESDAY THROUGH SUNDAY/
VFR conditions expected through the 24hr Forecast Period.

VFR conditions are expected to prevail over the next 24 hours at all TAF sites. High pressure and upper level ridging should keep skies mostly clear outside of afternoon cumulus developing.
Winds are expected to be out of the southwest during the day between 5 and 10 knots, falling near calm overnight tonight.

EXTENDED AVIATION OUTLOOK...VFR conditions will generally prevail, but some restrictions are possible in scattered convection with a cold front on Friday.

CAE WATCHES/WARNINGS/ADVISORIES
SC...None.
GA...None.