textproduct: Columbia

WHAT HAS CHANGED

Freezing Fog Advisory expanded further north up the I-77 corridor and east for lower visibilities and light ice accretion. Aviation discussion also updated.

KEY MESSAGES

- 1) Freezing fog leading to lowering visibilities and light ice accretion.

- 2) Dry cold front moving through this evening leading to gusty winds.

- 3) Temperatures near to below average through the weekend followed by a significant warmup next week.

DISCUSSION

KEY MESSAGE #1: Freezing fog leading to lowering visibilities and light ice accretion.

Freezing fog developed over Orangeburg, Bamberg, and Barnwell counties and while visibilities have begun to slowly improve, Orangeburg Airport recorded a hundredth of an inch of ice accretion. The fog has expanded further north and east so the Freezing fog advisory has been expanded. While widespread impacts remain unlikely, slick spots will be possible on elevated bridges and overpasses. Temperatures will likely warm above freezing shortly after sunrise.

KEY MESSAGE #2: Dry cold front moving through this evening leading to gusty winds.

Surface low pressure over the southern Hudson Bay will deepen today as it moves eastward. Aloft a shortwave over the Great Lakes will shift into the Mid Atlantic. While southwesterly flow will increase in the low levels, moisture will be limited as flow aloft remains westerly and northwesterly. As a result, expect a mostly dry frontal passage, although a slight chance of isolated showers in Lancaster or Chesterfield counties. Winds increase with tightening pressure gradient, becoming breezy today with gusts up to 30 mph. While impacts on lakes will be limited, as the front pushes through, cold advection will lead to improved mixing overnight. With the NAEFS mean indicating the 850mb jet will be above the 90th percentile, there will be potential for gusts around 35 mph over the relatively warmer lakes. A Lake Wind Advisory will be in effect beginning at 7pm this evening and continuing through 1 pm Saturday, after which high pressure will ridge into the area.

KEY MESSAGE #3: Temperatures near to below average through the weekend followed by a significant warmup next week.

Expect temperatures to be near to below average through the weekend with cold advection expected behind the cold front. Relatively strong radiational cooling Saturday night into Sunday morning will lead to temperatures in the low to mid 20s, expected to be the coldest night/morning in the period. Upper ridging late this weekend will begin to build over the central US with blended guidance favoring above well normal temperatures next week; temps 10-15 degrees above average are likely with daytime highs possibly getting into the 70's by late next week.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

Some intermittent MVFR vsbys possible through sunrise then generally VFR conditions expected.

Some lingering MVFR vsbys in fog or freezing fog but vsbys are improving at the terminals. Otherwise, other than some passing high clouds VFR conditions are expected for the remainder of the forecast with strong southwesterly winds picking up to around 15 knots with gusts to 25 knots after 15z ahead of an approaching dry cold front. The front should cross the region during the 00z-02z time frame and shift winds to the west- northwest and continue to be strong and gusty through the end of the forecast period.

EXTENDED AVIATION OUTLOOK...No anticipated aviation concerns through early next week.

CAE WATCHES/WARNINGS/ADVISORIES

SC...Lake Wind Advisory from 7 PM this evening to 1 PM EST Saturday for SCZ016-018-020>022-025>031-035-037-038-041-115-116- 135>137. Freezing Fog Advisory until 8 AM EST this morning for SCZ035- 038-041-135>137. GA...Lake Wind Advisory from 7 PM this evening to 1 PM EST Saturday for GAZ040-063>065-077.