textproduct: Charleston

SYNOPSIS

High pressure will extend across the region through Saturday. A cold front will push offshore Sunday morning followed by another area of high pressure. Yet another cold front could impact the Southeast States by the middle of next week.

NEAR TERM /THROUGH TONIGHT/

Fog has lingered across the region this morning and into the early afternoon. Conditions look to be improving away from locations along the immediate coastline and temperatures have begun rising into the mid to upper 60s. The forecast is on track for high temperatures today to reach into the low to mid 70s. Along the beaches, however, the fog is being particularly stubborn. While the fog is not technically sea fog, it is being influenced by the adjacent cooler waters and will likely persist through the afternoon and potentially into the overnight period.

Conditions tonight look prime for fog formation once again. A weak stalled front is located just south of the forecast area as of noontime, and is forecast to slowly progress back northward as a warm front this evening. The region will remain under the influence of southwesterly flow aloft as ridging builds into the southeastern states. This SW flow aloft will continue to advect a warm, moist airmass into the region with overnight temperatures only bottoming out in the mid to upper 50s. Probabilities of visibilities <0.5 miles are similar to that of last night and condensations pressure deficits are slightly lower. Fog remains in the forecast and a Dense Fog Advisory will likely be needed for portions, if not all, of the forecast area tonight.

SHORT TERM /FRIDAY THROUGH SUNDAY/

Friday and Saturday: A warm airmass will remain in place through Saturday with the region with holding along the southern periphery of high pressure as it shifts offshore of the Mid-Atlatic states. Another round of fog appears likely Friday night with low condensation pressure deficits and high low-level moisture levels progged. Some of the fog could be dense, possibly reaching Dense Fog Advisory criteria. Dry conditions will mostly prevail as ridging aloft builds and shift east of the region ahead of storm system organizing over the Southern Rockies and the Desert Southwest. A few marine-based showers could brush parts of the coast, mainly from Tybee Island north, as the return flow veers more southerly as a weak coastal trough lifts north Friday morning. Significant rainfall is unlikely and looks to mainly concentrate Friday night into Saturday coincident with a strengthening low-level jet ahead of an approaching cold front. Highs look to warm into the upper 70s/lower 80s both afternoons (except cooler at the beaches) and overnight lows will range from the upper 50s/near 60, except a few mid 50s possible in the Francis Marion National Forest. Record highs could be challenged each day with lows Friday night challenging the record high minimums. See the climate section below for specific records.

Saturday Night and Sunday: A cold front will push offshore early Sunday morning as a powerful shortwave pivots across the Great Lakes region. A band of rain associated with the front will likely be in a weakening phase as the corridor of strongest forcing with the Great Lakes shortwave with the right entrance region of the 165 kt polar jet pass by well to the north. How quickly the frontal band weakens is still a bit uncertain with areas across far interior Southeast Georgia the most likely to see measurable rainfall. Pops will range 30-60% for now, highest in the Allendale-Reidsville corridor, but further refinements in both the QPF and pops are likely. Lows will range from the lower 50s well inland to the upper 50s at the coast. The record high minimums could again be challenged, especially at KCHS. Highs behind the front Sunday will range from the lower 60s well inland to the mid 60s east of I-95. See the climate section below for specific records.

Modest cold air advection could push winds to near Lake Wind Advisory levels on Lake Moultrie Sunday afternoon.

LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/

Modest cold air advection could push winds to near Lake Wind Advisory levels on Lake Moultrie Sunday night. Otherwise, temperatures will return to more seasonable levels next week as a modified Canadian airmass prevails across the Southeast States. A could front could bring an increased risk for light rainfall by mid- week.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Fog has finally cleared the terminals and the 18Z TAF period will start with VFR conditions at KCHS/KJZI/KSAV. However, fog is in the forecast again tonight with impacts beginning as early as 03Z. MVFR conditions will deteriorate to IFR and LIFR as fog overspreads the region. Similar to today the fog could be slow to scour and have flight restrictions into the mid to late morning hours on Friday.

Extended Aviation Outlook: There is a risk for significant fog impacting all three terminals Friday night into Saturday morning. A band of showers with a cold front may bring reduced vsbys early Sunday morning. Gusty northwest winds are possible Sunday afternoon.

MARINE

Rest of This Afternoon and Tonight: Local webcams and satellite imagery show that fog is lingering along the immediate coastline this afternoon. While not technically sea fog, the fog is being influenced by the relatively cooler marine waters. The Marine Dense Fog Advisory has been extended until 4 PM. It is likely that this advisory will either need to be extended again this afternoon, or canceled and reissued with the threat of fog again tonight. Conditions across the marine zones will remain within a light wind regime, generally around 5 knots. As the warm and moist airmass remains over the region the threat of sea fog will continue into tonight, especially given the current fog is very stubborn to scour.

Friday through Monday: The risk for marine fog could linger over the coastal waters into the day Friday with fog possibly redeveloping Friday night into Saturday as a warm, moist airmass holds across the region. The fog could be dense with vsbys 1 NM or less, so Marine Dense Fog Advisories may be needed. The risk for Small Craft Advisory conditions from both winds and seas will peak Sunday into Sunday night as modest cold air advection occurs behind a cold front.

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...Dense Fog Advisory until 4 PM EST this afternoon for AMZ330- 350-352-354.