Area Forecast Discussion
Issued by NWS Charleston, SC

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000 FXUS62 KCHS 261423 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1023 AM EDT TUE JUL 26 2016 .SYNOPSIS... Atlantic high pressure will prevail through much of the week while a weak trough persists inland. && .NEAR TERM /THROUGH TONIGHT/... Today: Strong and persistent deep layered ridging will continue across the forecast area. Warm mid level temps, extensive dry air and subsidence aloft will again to combine to negate development of diurnal convection this afternoon across most of the forecast area. There will be some low level moisture advection across the Florida Panhandle and southwest Georgia this afternoon. However, the better instability and the Gulf Coast sea breezes will be removed from our southern Georgia zones. It is unlikely isolated convection reaches this region toward late afternoon, but did maintain some slight chance POPs closer to the Altamaha River. We went with a dry forecast at Savannah given forecast sounding trends and consensus of dry returns from most of the convection allowing models. This is not to say a spotty shower or tstm could develop just about anywhere along the Georgia sea breeze corridor this afternoon. Any localized updrafts should be brief and short- lived. Persistent temperature forecast with mid 90s and a few upper 90s further inland. Heat indices will reach 102 to 105 degrees in most areas this afternoon. Tonight: Quiet weather will persist as mid level ridging and the surface synoptic pattern remain stagnant. Skies will be mainly clear some late night showers off the coast once again. No changes to forecast low temps...mid to upper 70s once again. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... Strong mid/upper level ridging directly over the area will continue into the second half of the workweek. At the surface, Atlantic high pressure dominates locally with troughing well inland. POPs will remain below climo values given the amount of subsidence aloft, with only slight chance mainly along the sea breeze corridor Wednesday and Thursday, and mentionable POPs left out Friday as the majority of global model operational and ensemble members keep the area dry Friday. Persistent heat remains the main weather story for the forecast period. Heat indices will top out in the mid-100s daily, and though some coastal areas will briefly approach heat indices of 110 right along the seabreeze, no heat advisories are expected through the period. Muggy overnight conditions can be expected with lows only dipping to near 80 along the coast and upper 70s inland. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... Ridging overhead will weaken heading into the weekend and POPs will return closer to climo levels with a warm and humid airmass in place at the surface. The ridge will slide off the Southeast Coast Sunday and modest height falls aloft will bring more unsettled weather early next week. A cold front associated with low pressure lifting across the Great Lakes may reach as far south as the Carolinas before dissipating Monday and Tuesday. Global models currently focus moisture pooling and enhanced convective initiation near this front across North Carolina and the South Carolina Upstate Monday and Tuesday, and with 700mb steering flow gradually shifting more WNW, some of this activity could advect into our area during this time. POPs well into the chance range have been introduced for the early part of next workweek, especially across and north of the Charleston Metro. Temps will remain well above normal through the period as the warm and humid airmass remains anchored over the area with ample sunshine each morning. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... VFR through 12Z Wednesday. Extended Aviation Outlook: VFR will prevail at both sites. Brief flight restrictions possible with isolated afternoon showers/thunderstorms mainly over the weekend. && .MARINE... Day to day changes have become quite subtle with a synoptic pattern this steady. The forecast through tonight is one of persistence with s to sw flow peaking at 15 kt late day and overnight and ebbing below 10 kt from mid morning through the early afternoon hours. Through tonight, seas will generally average 2 to 3 ft. Showers and tstms are possible mainly seaward from the pilot buoys late tonight. Wednesday through Sunday: Atlantic high pressure will prevail through the period with south-southwest winds mainly 10 to 15 knots and seas generally 2 to 3 feet, with gusts to 20 kt and seas to 4 feet across the outer Georgia waters during the early morning hours. A stray early morning shower/thunderstorm is possible through the end of the workweek, with thunderstorm chances and the associated threat for frequent lightning increasing this weekend. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM...CEB AVIATION... MARINE... is the U.S. government's official web portal to all federal, state and local government web resources and services.