textproduct: Columbia

SYNOPSIS

After a chilly start, warmer and breezy conditions are expected today ahead of a dry cold front. Dry conditions continue into the weekend with near to slightly below normal temperatures. A colder air mass may move in behind another cold front early next week.

NEAR TERM /THROUGH TONIGHT/

Key message(s):

- Areas of fog or freezing fog possible this morning.

- Breezy conditions ahead of a dry front, with a Lake Wind Advisory in effect this afternoon through this evening.

High pressure in the region has resulted in weak winds aloft and at the surface early this morning. Satellite imagery is just showing a bit of high clouds passing overhead, but surface obs are indicating the development of some lower decks and also lowered visibilities over the next several hours. Guidance is more bullish early this morning with the development of fog, and potentially freezing fog given temperatures in the upper 20s and low 30s. This would result in some slippery conditions for the morning commute, particularly for bridges, though widespread problems are unlikely with most road temperatures being too warm.

Breezy conditions are expected to develop this afternoon as a deepening upper low moves east of the Great Lakes and strengthens the pressure gradient ahead of the associated cold front. Southwest winds will slowly increase this morning, eventually becoming 10 to 20 mph with gusts in excess of 25 mph. This is expected to create some hazardous conditions on area lakes. An adjustment of the start time of the Lake Wind Advisory was made to better line up with a slightly later onset of stronger wind speeds after about 18z this afternoon. Windspeeds should be strongest just ahead of and with the front, which should pass through the forecast area this evening shortly after about 03z this evening. Wind gusts should then ease as the gradient relaxes and winds become more from the west. With PWATs less than 0.75" just about everywhere, no precip is expected to occur with the front. Windspeeds however do remain somewhat elevated through the night and low temperatures are not expected to fall quite as sharply. This surface mixing will also negate any repeat fog or freezing fog threat tonight.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/

Key message(s):

- Not as warm on Thursday as high pressure builds in from the west. Temperatures increase once again on Friday.

The axis of the shortwave should be just east of the FA at the start of the period, transitioning to broad longwave troughing which will slowly pull poleward through the short term. At the surface, high pressure will approach from the west and will be the primary driver of our weather during the late week period, maintaining dry conditions and mainly sunny skies. Temperatures on Thursday will likely be colder than today due to the presence of the aforementioned trough and modest CAA with forecast highs in the upper 40s to lower 50s. Clear skies and fairly light winds associated with approaching high pressure should promote decent radiational cooling at night with forecast lows in the upper 20s to lower 30s. Winds are expected to shift southwest by daybreak Friday, setting the stage for a warmer day as temperatures climb into the mid-50s to near 60 degrees. There may be a few more clouds around near the North Carolina border on Friday, limiting daytime heating, as a weak disturbance passes to the north. Idealized radiational cooling is likely Friday night dropping temperatures into the 30s.

LONG TERM /SATURDAY THROUGH TUESDAY/

Key message(s):

- Near normal temperatures and continued dry conditions expected this weekend.

- A cold front crosses the region on Sunday and may be followed by a colder air mass early next week though its duration over the FA remains unclear.

The upper flow will be more zonal on Saturday before another shortwave trough emerges out of Minnesota and passes to the north on Sunday. This should be followed by ridging moving in towards the end of the extended. Meanwhile, high pressure and southwest flow will continue at the surface this weekend, keeping the FA dry with near normal temperatures, until the passage of a dry cold front on Sunday. There remains a large temperature variance in the ensemble guidance during the early week period, but it appears that Monday will feature much colder temperatures potentially followed by quick return to near normal values as the aforementioned upper ridge moves in during the middle of next week. The chance of rain through Tuesday is low, less than 20 percent.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

Periodic restrictions continue for a few hours this morning due to fog and/or stratus.

Confidence has waned regarding widespread freezing fog this morning. There still remains a better chance for restrictions at OGB/AGS, but the threat should end by 14z or 15z. At this point, strong upper winds begin to mix down to the surface. Winds start out light and variable to calm early this morning, then increase out of the SW at around 10 kts by late morning. Speeds closer to 15 kts and gusts of 25 kts should then kick in this afternoon and through early this evening. Elevated WLY winds continue through midnight tonight before gusts start to decrease as the pressure gradient weakens behind a front.

EXTENDED AVIATION OUTLOOK...Dry air will hinder widespread restrictions through much of the extended, but localized fog along river valleys will be possible some mornings.

CAE WATCHES/WARNINGS/ADVISORIES

SC...Lake Wind Advisory from 1 PM this afternoon to 1 AM EST Thursday for SCZ016-018-020>022-025>031-035-037-038-041- 115-116-135>137. GA...Lake Wind Advisory from 1 PM this afternoon to 1 AM EST Thursday for GAZ040-063>065-077.