Area Forecast Discussion
Issued by NWS Columbia, SC

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000 FXUS62 KCAE 262321 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 721 PM EDT Wed Apr 26 2017 .SYNOPSIS...
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A frontal boundary approaching from the west will become diffuse Thursday night. Moisture associated with the front will bring a chance of showers and thunderstorms Thursday afternoon and night. Fair and warm Friday and Saturday. Increasing moisture late Sunday into Monday as another front moves toward the region.
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&& .NEAR TERM /THROUGH Tonight/...
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Mainly clear skies through the evening. Toward morning...as ridge moves to the east low- level moisture may increase ahead of the weak cold front. No precipitation expected tonight but increasing clouds...strato-cu possible especially in the CSRA around daybreak. Mixing in the boundary layer as pressure gradient increases will limit fog development.
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&& .SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
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Upper ridge will shift east Thursday as an upper trough over the Midwest lifts northeastward. Models indicate that the stronger dynamics will be well north of the forecast area. An associated cold front will approach the region from the west and is expected to weaken as it reaches the forecast area late Thursday afternoon/evening. Scattered showers and thunderstorms are expected mainly during the late afternoon and evening, although the 12Z NAM is a little slower than the 12Z GFS with the timing of the convection. Instability appears weak to moderate with model LI values -1 to -3. Model soundings show a mid-level cap through late afternoon. Maximum precipitable water values are around 1.75 of an inch, so cannot rule out an isolated heavy rain threat. Most of the activity will shift east by late Thursday night. Above normal high temperatures in the middle 80s expected ahead of the front Thursday. Increased southwesterly flow will promote breezy conditions.
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&& .LONG TERM /FRIDAY THROUGH WEDNESDAY/...
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The cold front will remain near the area Friday and become diffuse providing a slight chance of convection. Models indicate another mid-level cap Friday with weak to moderate instability. It will be hot and dry over the weekend as an upper high builds off the Southeast coast, although isolated convection will be possible given lingering moisture. High temperatures Saturday are expected to reach the lower 90s in many locations. An upper low over the Plains will lift toward the Great Lakes region Sunday into Monday. An associated strong cold front will approach the area Monday with severe thunderstorms possible. Models show increased southwesterly flow into the upper low which will increase the moisture flux into the area. Surface high pressure situated over the Gulf will build into the area for Tuesday and will be off the Southeast coast for Wednesday. Tuesday appears slightly cooler in the wake of the front with high temperatures returning to near normal values. Temperatures will recover Wednesday returning back into the lower 80s.
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&& .AVIATION /00Z THURSDAY THROUGH MONDAY/...
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Ceilings restrictions mainly at the southern terminals may develop in the morning. It will be breezy in the afternoon. The southerly flow between offshore high pressure and an approaching weak cold front will bring increasing moisture. Expect stratocumulus will develop with fog limited by boundary layer wind. The GFS and NAM MOS suggested MVFR ceilings developing at AGS and DNL, and VFR ceilings at the remaining terminals. We followed the GFS LAMP for the timing. Wind will increase ahead of the front. The NAM Bufkit momentum transfer tool indicated gusts 20 to 25 knots during the afternoon. Lingering mid-level capping as indicated by the models may help limit thunderstorm coverage. The ARW and SPC WRF indicated scattered coverage. The thunderstorm chance was too low to include in the terminal forecasts. EXTENDED AVIATION OUTLOOK...Widespread IFR stratus and fog associated with the remnants of a front may occur during the early morning hours Friday and Saturday. Widespread IFR stratus may occur mainly during the early morning hours Sunday with increased moisture ahead of a cold front. Gusty winds and restrictions in thunderstorms may be an issue with the front Monday.
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&& .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99

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