Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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987 FXUS62 KCHS 141354 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 954 AM EDT Fri Jun 14 2024 .SYNOPSIS... A stationary front will meander near or just off the coast through the end of the week. A weak cold front will drop into the forecast area early this weekend before high pressure spreads in from the north. && .NEAR TERM /THROUGH TONIGHT/... Late this morning: Surface analysis and satellite imagery shows that the area of low pressure off the coast is centered to the southeast of the NC Outer Banks. All is clear across the forecast area this morning, other than scattered weak showers over the Georgia coastal waters along an area of convergence likely associated with a land breeze. This shower activity will continue to move to the south and away from the coast over the next couple of hours. By the afternoon we will lose the influence of the aforementioned surface low as it pulls further away. This means the northerly and northeasterly flow we are experiencing now will end and onshore flow will develop with the diurnal sea breeze. The airmass is pretty dry across the region, with some areas of precipitable water values less than an inch across central Georgia and the South Carolina Midlands. Model soundings are dry and capped, so we continue to advertise a dry forecast. If we were to see an isolated shower or storm, it would likely be along the Georgia coast where there is a little better available moisture as evidenced by some early developing cumulus. It will be warm day, with highs in the low to mid 90s away from the immediate coast. Tonight: A backdoor cold front will approach the forecast area from the north. South term guidance indicates that the front may reach the PeeDee Region across SC by 12Z Sat. Winds across the forecast area should remain light front the southwest through tonight. Given the light sfc winds and rising H5 heights tonight, low temperatures should generally range between 70-75 degrees. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... Saturday: Ridging aloft will build into the southeastern states from the southwest, while at the surface a cold front will be located just to the north of the forecast area at daybreak. A hot day is forecast, with high temperatures reaching into the upper 90s away from the beaches. Heat index values are expected to reach between 100-104F, falling short of Heat Advisory criteria. The cold front is forecast to push through the forecast area through the daylight hours, although it is expected to weaken as it moves southward. Between the front and the local sea breeze circulation isolated to possibly scattered showers and thunderstorms are forecast to form, mainly in the afternoon hours. Even with PWAT values approaching 1.6 inches, model soundings indicate that there is likely going to be a considerable amount of mid-level dry air in place, hindering convective initiation. Overnight lows will be quite mild, only dropping into the low 70s inland, with mid to upper 70s closer to the coastline. Sunday: The center of high pressure aloft will shift to be directly over the southeastern states. At the surface, the remnants of the aforementioned cold front will be stalled across southeastern GA. This feature will slowly sink further southward as high pressure builds in from the north. There will likely be enough lingering moisture for the afternoon sea breeze to trigger isolated to scattered showers and thunderstorms. Highs across southeastern SC are forecast to reach into the low 90s, with mid to upper 90s across southeastern GA. Heat Index values across southeastern GA could once again reach 100-101F. Overnight temperatures are forecast to dip into the upper 60s across inland SC, with low to mid 70s elsewhere. Monday: The center of high pressure aloft will remain over the southeastern state. At the surface high pressure will continue to build into the forecast area from the north. Temperatures are forecast to reach into the low 90s inland, with upper 80s along the coastline. Some moisture streaming in from the Atlantic may be enough to spur isolated to possibly scattered showers and thunderstorms along the coastal areas of southeast GA. Otherwise, dry conditions are forecast as plentiful dry air encompasses the forecast area with the building high pressure both aloft and at the surface. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Through the end of the week high pressure looks to hold strong over the local forecast area, both at the surface and aloft. Precipitation chances look to be limited to the adjacent coastal waters, where moisture will be greatest. Some of these showers/tstorms could possibly brush the beaches, although overall conditions appear to be dry. Temperatures are forecast to sit right around to slightly above normal. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... 12Z TAFs: Low pressure over the western Atlantic will track to the northeast today. As the low departs, a drier air mass will be drawn across the forecast area with NE winds. A sea breeze is timed to develop this afternoon, reaching KJZI by 18z and KCHS and KSAV between 19-20Z. In the wake of the sea breeze, winds should shift from the SE around 10 kts. Winds should settle from the SE this evening, decreasing to around 5 kts. It is possible that as winds decouple late tonight, patchy fog or ground fog could develop over KSAV between 9-12Z, highlighted with a TEMPO. Extended Aviation Outlook: Prevailing VFR. Brief flight restrictions are possible with isolated showers and thunderstorms Saturday afternoon. && .MARINE... At dawn, visible satellite and KCLX data indicated a narrow band of clouds associated with a land breeze just off the GA and SC coast. The Waterspout Index indicates a low risk for waterspouts along this boundary this morning. We will continue to monitor conditions through daybreak. The sfc pattern should yield NE winds between 10 to 15 kts this morning, seas between 2-4 ft. A sea breeze is expected to develop during the early afternoon hours, shifting winds from the east. Tonight, weak high pressure will slide over the marine zones by late tonight. Southwest winds of 5 to 10 kts should remain across the coastal waters tonight. Seas are forecast to range from 2-3 ft. Saturday through Wednesday: Generally tranquil marine conditions are expected through the middle of next week, with southeast winds Saturday generally less than 10 knots shifting to the northeast by Monday and increasing to 10 to 15 knots. Seas are forecast to average 2 to 4 ft. Rip Currents: Gusty NE winds will remain through this morning, then becoming onshore this afternoon. Additionally, a SE swell around 2 ft near 7 seconds should impact the beaches along with a potentially moderate longshore current. This could lead to rip currents. Hence, there is a Moderate Risk for the GA beaches, especially Tybee Island. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...BSH/NED SHORT TERM...CPM LONG TERM...CPM AVIATION...CPM/NED MARINE...CPM/NED