Area Forecast Discussion
Issued by NWS Columbia, SC

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000 FXUS62 KCAE 192356 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 756 PM EDT Mon Mar 19 2018 .SYNOPSIS... A warm front will lift northward and into the area tonight ahead of approaching low pressure. The low will be in the region Tuesday and northeast of the area Wednesday. && .NEAR TERM /UNTIL 7 AM TUESDAY MORNING/...
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A warm front is slowly lifting northward across southern Georgia, while a cold front moves eastward through Mississippi. Isolated to scattered showers/storms expected to develop along the lifting warm front later tonight, and move towards portions of the CSRA. Then after Midnight, a potential squall line in advance of the cold front may then move across the cwa. MUCAPE values will be higher overnight due to the cooler mid-levels. However a stable near-surface layer will help to limit the severe potential. Expect the line of thunderstorms along the warm front to break up as it moves into the southern cwa and into the upper ridge early tonight. Hrrr does show the squall line ahead of the cold front moving through the area after Midnight. Although the threat of severe weather becomes increasingly isolated through the night we cannot rule out small hail, damaging wind gusts, and even an isolated tornado with some of the stronger cells. Overnight lows remaining mild with cloud cover expected. Readings from the middle 50s north, to the lower 60s south.
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&& .SHORT TERM /7 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... A shortwave trough will move across the Southeastern US and through the forecast area Tuesday afternoon and evening. Models show an area of low pressure and an associated cold front in the area shifting east. There is still some uncertainty regarding the timing of the system and how far west into the forecast area the moisture will be. The GFS pushes the deeper moisture east of the area by 21Z while the NAM is slower pushing the moisture east. A few strong to severe thunderstorms will be possible particularly south and east of the I-20 corridor mainly during the late morning and through the afternoon hours. The far eastern portion of the area is in the Storm Prediction Center`s slight risk for severe weather. The primary threats appear to be strong to damaging winds, isolated tornadoes and hail. Model LI values are around -5 to -7 with 0 to 6 km shear values around 55 knots. Latest model guidance is trending warmer further north with temperatures on Tuesday. This will ultimately depend on the position of the warm front, but believe northern counties will reside in the warm sector. Models show the area becoming more stable Tuesday night. With the upper low north of the area and wrap around moisture Tuesday night, have continued likely pops north Tuesday night and slight chance south. Winds will stay up Tuesday night with temperatures forecast in the lower 40s. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... The shower chance Wednesday will be greatest in the north section closer to deeper moisture and colder air aloft. Reduced pops some on Wednesday especially further south given that the models are pushing the upper low northeast of the area more quickly and moving the moisture out of the area. Wednesday appears quite breezy with a tight pressure gradient in the area. Dry ridging is forecast to dominate Thursday and Friday. The GFS and ECMWF MOS have temperatures during the early morning hours Thursday and Friday in the middle and upper 30s. It may be cold enough for frost. The models show much of the moisture associated with a warm front north of the forecast area Saturday and little moisture along a cold front Sunday. The GFS and ECMWF MOS have pops 20 to 30 percent. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/...
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Broad upper trough over the central CONUS with weak upper ridging off the SE coast. Closed upper low moving east towards the Ohio valley. Surface low over W TN with warm front to our west and south. Upper impulses interacting with the front providing convection over S GA/N FL. This activity is expected to shift east and remain just south of our forecast area (FA) this evening. Warm front to shift north into our FA tonight ahead of a cold front and prefrontal band of convection, currently stretching across central TN into N AL, approaching from the NW. Will expect lowering CIG heights later tonight in response to the approaching warm fron and will include LLWS with indications of a fairly strong low level jet developing. Main concern will involve potential for convective activity, possibly severe, to affect the FA late tonight. Main upper energy to remain just to our north, with some guidance indicating the convective activity weakening as it moves into our FA. However, latest HRRR maintains potent band of convection moving across the FA 06Z-10Z tonight. Combination of shear and mainly elevated instability will provide a severe threat with strong straight line winds appearing to be the main threat. Due to uncertainity, will indicate a predominant period of SHRA with VCTS late tonight, and tweak later based on radar trends and latest guidance. Improving CIGs expected Tuesday morning. Main upper trough will come through late Tuesday with main cold front pushing through the northern FA during the morning, and through the central and eastern FA Tuesday afternoon. Some convective activity will be possible mainly S/E FA and towards the coast Tuesday afternoon, and could be severe, and would be more likely to affect OGB than the other TAF sites. Breezy conditions expected to develop Tuesday. EXTENDED AVIATION OUTLOOK...Some CIG restrictions possible late Tuesday night and Wednesday morning. Otherwise, VFR and continued breezy through Thursday.
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&& .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$ is the U.S. government's official web portal to all federal, state and local government web resources and services.