Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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160 FXUS62 KCHS 081743 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 143 PM EDT Sat Jun 8 2024 .SYNOPSIS... High pressure will prevail through the weekend, before a cold front moves through the area on Monday. The pattern is expected to turn more unsettled through mid to late next week. && .NEAR TERM /THROUGH TONIGHT/... Early afternoon update: No major changes made. There is just a hint of Cu along the sea breeze boundary in southeast Georgia up into Beaufort County...where surface dewpoints remain highest...and just a hint of Cirrus. But mainly sunny skies otherwise. Per temperature trends, readings are indeed running a little behind yesterday...as anticipated. Forecast highs were tweaked downward just a touch accordingly. Previous discussion... Morning analysis reveals surface high pressure from the lower Great Lakes to the Gulf Coast, centered across Tennessee/Alabama. Surface boundary is well to our east/south with a nice wedge of dry air/PWAT values under 1 inch evident on the morning satellite Total Precipitable Water product...edging through the southeast region. Surface high pressure will settle over the southeast region through today although weaken a bit in time. But deep layer dry air will be rule with surface dewpoints dipping through the 50s away from the coast, possibly some upper 40 dewpoints well inland and little opportunity for diurnal Cu development. But despite the drier air mass, thermal profiles are only slightly cooler compared to Friday, with H8 temps off maybe a degree C or so and suggesting highs a couple degrees cooler...89-94F. However, with dewpoints in the 50s, it will definitely be more comfortable. Tonight, the pattern across the CWA will feature weak sfc high pressure with slight H5 ridging. Conditions should favor a mostly clear sky with light to calm winds. Low temperatures are forecast to range from the upper 60s inland to the low to mid 70s along the coast. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... Sandwiched between Atlantic and inland surface high pressure with nearly zonal flow aloft will make for a rain-free weekend day Sunday. Skies will be mostly sunny and dew points will mix out into the mid to upper 50s inland. Min RHs will then dip into the 25-30% range. Fire weather concerns are fairly low at this time in the absence of gusty winds and dry soils. Temperatures will continue to run above normal with highs expected to soar into the mid to upper 90s Sunday. Some locations could even reach near record high temperatures (see Climate section below). Overnight, low temperatures will remain mild - only dipping into the low 70s inland and mid/upper 70s near the coast. Late Sunday into early Monday, a weak cold front will push across the area as shortwave energy to the north passes. With deep moisture and forcing limited to the north, isolated showers will also be limited to the Charleston Tri-County overnight. As some of the higher dew point air seeps south through the day Monday, scattered CI is possible, mainly along the afternoon sea breeze. Monday will be a bit cooler in comparison to Sunday with highs in the low to mid 90s. Min temps will drop into the upper 60s away from the beaches. Some uncertainty is in play for Tuesday`s forecast as the latest guidance shows the deeper moisture mostly offshore by Tuesday. Model soundings show a fairly pronounced layer of drier air moving in aloft and convection would struggle to develop in this environment. However, with forcing mechanisms still in place (sea breeze, llvl convergence, and weak DPVA) we could see some showers and thunderstorms where forcing is strong enough and/or any lingering moisture exists. Chance POPs are still in place, however these could be lowered in the future if the drier trend continues. Temperatures are forecast to reach the upper 80s to low 90s Tuesday. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... The general pattern is for a large, unorganized area of low pressure to potentially develop somewhere in the Gulf of Mexico. Most models indicate that at least some of the deep layer/tropical moisture associated with this area could spread northeastward toward our region, especially mid to late next week. The trend continues to show increasing precipitation chances through the end of next week. We will continue to monitor the potential for locally heavy rainfall, but as of now it is too early to determine QPF/rainfall totals. Temperatures should be near to slightly below normal as increasing moisture/clouds/precip chances limit daytime heating. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... VFR conditions will prevail at KCHS, KJZI, and KSAV through 18Z Sunday. Sea breeze will push across the terminals this afternoon, turning winds into the southeast along with an uptick in wind speeds. Winds go near calm tonight. Some mid and high cloud cover will be advancing into the region from the west through the course of the night and into Sunday. Extended Aviation Outlook: VFR conditions will prevail through Sunday night. The chances for convection will increase through the week bringing the potential for periodic flight restrictions. && .MARINE... Today and tonight: A weak cold front will push over the western Atlantic as sfc high pressure remains centered over the Deep South. A weak sea breeze is forecast to develop this afternoon. Winds will veer from the southeast around 10 kts this afternoon, then turning from the southwest between 5 to 10 kts tonight. Seas are forecast to range between 1 to 2 ft. Sunday through Thursday: The general pattern will support the typical southerly/southwesterly flow with winds around 10-15 kt and seas 2-3 ft through the middle of next week. Winds are expected to shift easterly Tuesday through Thursday as broad low pressure develops in the Gulf of Mexico. && .CLIMATE... Record High Temperatures June 9: KCHS: 99/1986 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...Adam/NED SHORT TERM...BRM LONG TERM...BRM AVIATION...Adam/BRM/NED MARINE...BRM/NED