Area Forecast Discussion
Issued by NWS Columbia, SC

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000 FXUS62 KCAE 250610 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 210 AM EDT Mon Jun 25 2018 .SYNOPSIS... High pressure will extend from the Atlantic westward into the Gulf of Mexico through today. A hot westerly flow will continue north of this ridge locally and high temperatures will be in the mid 90s to around 100 degrees. A cold front will push into the forecast area tonight and Tuesday bringing showers and thunderstorms. Tuesday should be the coolest day in the past week or so due mainly to increased cloud cover. A more climatological pattern unfolds for the remainder of the period with increasing moisture and ridging into the Southeast. This pattern supports scattered diurnal thunderstorms and above normal temperatures. && .NEAR TERM /THROUGH TONIGHT/... The main concern will be the possibility of severe thunderstorms and localized flooding. A surface trough will be in the forecast area today ahead of the approaching cold front. The front is forecast to sink southward and into the area tonight. Despite strong heating and convergence into the surface trough, upper ridging will likely limit thunderstorm coverage during much of today except there may be considerable coverage in the north section late this afternoon with moisture pooling ahead of the cold front plus an approaching mid-level shortwave trough. The greatest coverage may be this evening closer to the maximum of diurnal instability and ahead of a mid-level shortwave trough and in an area of convergence near the front. There will be a continued threat of thunderstorms overnight with the front and upper feature in the area. The NAM and GFS depict strong instability with surface- based LI values -8 to -10. Forecast soundings indicate considerable CAPE in the hail growth region. Damaging wind and hail will be possible with the thunderstorms. Precipitable water is forecast to be around 2 inches. High rainfall rates and possible training near the front support a possibility of localized flooding. We followed a guidance for the temperature forecast. Expect peak heat index values about 105 and just below the heat advisory criteria of 110 today. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... Some convection will likely persist through Tuesday morning, and with the front stalled just south of the area, scattered showers and thunderstorms will remain possible through the day. The increased cloud cover and slightly cooler air behind the front should make Tuesday one of the coolest days in the past week or so, with highs only in the upper 80s to lower 90s. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Transitional high pressure will build into the area on Wednesday. While diurnal convection is still possible, much drier conditions are expected. Both the GFS and ECMWF then show another shortwave moving through the region on Thursday, and scattered thunderstorms will be possible. A low will develop off the coast on Friday, as high pressure amplifies over the eastern US. Have kept chance PoPs across the area, but the better chance for convection will probably be across the eastern Midlands where there will be more moisture associated with the low. Onshore flow increases Saturday and Sunday with high pressure centered to the north, with supports warming temperatures and a climatological pattern of scattered afternoon convection. Expect highs in the mid to upper 90s and lows in the 70s. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... High low-level moisture and stability in the wake of convection may help support a period of stratus and fog during the early morning hours especially at AGS where the most rain occurred. Heating and mixing should dissipate any stratus and fog later in the morning. A surface trough will be in the forecast area today ahead of the approaching cold front. The front is forecast to sink southward and into the area tonight. Despite strong heating and convergence into the surface trough, upper ridging will likely limit thunderstorm coverage during much of today and the thunderstorm chance was too low to include in the terminal forecasts at this time. The greatest coverage may be this evening closer to the maximum of diurnal instability and ahead of a mid-level shortwave trough and in an area of convergence near the front. We included thunderstorms in the terminal forecasts during the 00z to 04z time frame. There will be a continued threat of thunderstorms overnight with the front and upper feature in the area. The NAM and GFS depict strong instability with surface-based LI values -8 to -10. Forecast soundings indicate considerable CAPE in the hail growth region. Damaging wind and hail will be possible with the thunderstorms. EXTENDED AVIATION OUTLOOK...Restrictions possible each day in early morning fog plus mainly afternoon and evening thunderstorms. && .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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