textproduct: Charleston

SYNOPSIS

High pressure will prevail across the region most of this week, bringing dry conditions and above normal temperatures. A cold front may bring showers and colder temperatures to our area this weekend.

NEAR TERM /THROUGH TONIGHT/

At sunrise: Satellite imagery shows a large area of stratus spreading across the forecast area from west to east that should reach the coast soon. This blanket of stratus, and a little bit of patchy fog, will take some time to mix out and scatter. It could linger through late morning, delaying the onset of insolation and heating. However, we should still see enough sun this afternoon to warm to our forecast values in the mid 70s.

Today: Aloft, zonal flow will gradually get replaced by broad ridging shifting to the east across the eastern half of the CONUS. At the surface, a surface low will track across New England while high pressure spreads across an area from the OH Valley to the Appalachians. Modest west-southwest flow will help yield a very warm afternoon, with highs expected to reach the mid 70s in many areas. Such values would be on the order of 15 degrees above normal for early January.

Tonight: The surface high centered near the central Appalachians will push a subtle backdoor front through the SC Midlands and just into the SC Lowcountry. It will be another mild night, with lows along and north of the boundary getting into the upper 40s and low 50s, with low to mid 50s to the south. There will likely be another smattering of low stratus and fog around the area, given the continued warm temperatures and lingering low- level moisture. Also of note, low-level flow across the nearshore coastal waters should turn more southerly with a longer fetch potentially supporting the development marine fog along the coast. This could result in fog and stratus issues along the beaches and the immediate coast. Low confidence in the timing, placement, and even the occurrence of fog, but worth watching.

SHORT TERM /THURSDAY THROUGH SATURDAY/

Thursday and Friday: Quasi-zonal flow persists over the Southeast with supported ensemble guidance indicating significant amplification yielding well above normal temperatures. At the surface, high pressure should continue to expand across the the northeastern Gulf and Atlantic waters and allow for quiet conditions to prevail. Expect temperatures the mid to upper 70s, with some spots in the low 80s across southeastern Georgia on Friday! It's very possible to see some near record highs on Friday (see Climate Section below). Temperatures near the coastline will be a bit cooler given the recent SSTs with highs only reaching into the mid to upper 60s. A rain-free forecast has been maintained on Thursday and Friday as subsidence associated with the high will keep the atmosphere quiet. Overnight lows remain very mild for January with temps staying above 50s.

Saturday: This is where the pattern changes as ensembles continue indicate that an upper-lvl trough located over the central CONUS will track towards the region on Saturday. Also, an associated surface cold front will approach the region, however it looks like it'll struggle to produce any meaningful rainfall as it'll have to overcome the antecedent dry conditions. It seems the system has slowed down a bit, favoring the machine learning model solution, which would indicate the strength of upper-lvl ridging could be a bit under-forecasted in the deterministic models. In response to this slow-down, the highest chance of rainfall appears to be Saturday night now with 30-40% PoPs noted. Even though this system won't be much of a rain-maker, it'll be fairly windy day with gusts reaching up to 20-22 mph in the afternoon. It will also be another warm day as temps. reach into the upper 70s across southeast South Carolina and low 80s across Southeast Georgia. It's possible to see record breaking temps. yet again (see Climate section below).

LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/

A cooler, drier airmass will settle into the region behind the front on Sunday morning, with a noticeable difference in dewpoints through early next week. Temps. on Sunday will reach into the low to mid 60s and skies should clear out in the afternoon leading to a fairly nice day. Thereafter, the temps. should remain in the low to mid 50s on Monday and Tuesday.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

The 12z TAF period begins with a large area of IFR stratus in the process of spreading into KCHS, KJZI, and KSAV. The TAF's will be initialized with IFR stratus that will likely linger through late morning and possibly midday. There could be some patchy fog with the stratus as well, but ceilings will be the primary factor for flight categories. VFR conditions should return to the terminals by around midday and should then prevail through the early morning hours overnight. All signs point to the potential for more fog and stratus across the area late tonight, but confidence is low in the coverage and placement.

Extended Aviation Outlook: An approaching cold front could bring increased probabilities for flight restrictions on Sat. night as scattered showers track through the region.

MARINE

Today through tonight: West-southwest to southwest flow will prevail across the local waters today with speeds around 10-15 knots around sunrise, diminishing a bit to 10 knots late in the day. Overnight, winds will be light, 5-10 knots early in the evening becoming 5 knots or less late. Seas are expected to be 2-3 feet today, dropping off to 2 feet overnight. One forecast issue to take note of is the potential for fog development overnight. With winds turning light and being out of the south- southwest in the early evening, conditions could become favorable. Model guidance is hinting at it, so it will need to be monitored.

Thursday through Sunday: As high pressure continues to settle across the waters, light northeasterly winds to persist on Thursday. It's important to note that there is potential for sea fog development on Thursday night as conditions look somewhat favorable. Ahead of the approaching upper-lvl trough, south- southeasterly winds might become a bit breezy on Friday night into Sunday. Seas range from 2 to 3 ft throughout most of the period, before a swell surges into the waters on Sunday and seas build to 4 to 6 ft. Small Craft Advisories might be needed in the nearshore South Carolina, nearshore Georgia, and outer Georgia waters on Saturday night into Monday given the enhanced winds and seas.

CLIMATE

Record High Temperatures: January 9: KCHS: 78/2012 KCXM: 76/1974 KSAV: 77/2008

January 10: KCHS: 79/2008 KSAV: 81/1972

Record High Minimum Temperatures: January 9: KCHS: 58/1946

January 10: KCHS: 60/1974 KCXM: 62/1974 KSAV: 63/1937

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...None. MARINE...None.