Scientific Forecaster Discussion
000 FXUS62 KCAE 142230 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 630 PM EDT Mon Oct 14 2019 .SYNOPSIS... A diffuse front lingering in the forecast area will become a warm front Tuesday ahead of an approaching cold front. The warm front will lift north of the area by Tuesday night. The cold front will cross the area Wednesday. The greatest moisture is forecast to be in the forecast area ahead of the cold front Tuesday night. Dry, seasonable weather remains in place through the remainder of the work week. Warmer temperatures return for the weekend with the next chance of rain towards the end of the long term. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Latest analysis reveals the frontal boundary may have pushed through the Midlands as dewpoints have fallen across the region, also aided by mixing as satellite imagery indicates mainly sunny skies. Precipitable water values have dropped significantly with values at or below a half inch north of the I-20 corridor with a strong gradient to higher values toward the coast as high pressure builds in from the Tennessee Valley. After the much needed rainfall overnight, no additional rain is expected through tonight with high pressure in place and the frontal boundary becoming diffuse or stalling to our south. Clouds will be on the increase later tonight as the next weather system develops over the middle of the country as an upper trough digs into the upper Midwest and moisture is pulled back northward ahead of it. Temperatures overnight will be impacted by the amount of cloud cover and this will be more noticeable in the southern Midlands and CSRA where clouds will arrive earlier and be thicker. Overnight lows expected to range from the mid 50s north to lower 60s south. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... An upper trough over the northern Rockies will dig southeastward Tuesday and Wednesday. At the surface, a frontal boundary located just east of the forecast area will lift northward as a warm front. Moisture will deepen on Tuesday from south to north with precipitable water values rising to 1.9 to 2.1 inches, which is 175 to 200 percent of normal. Widespread rainfall is expected by Tuesday night across the area. The GFS pops have trended down some for Tuesday. WPC has included portions of the southeastern FA in its Day 2 marginal and slight risk of excessive rainfall outlook. Heavy rainfall will be possible at times. Conditions have been relatively dry across the area recently, which should mitigate the threat of flash flooding. Highs on Tuesday in the middle to upper 70s. A cold front will cross the area on Wednesday. The deeper moisture will push northeast of the area ahead of the frontal passage. Scattered showers still seem reasonable. Most of the area should remain dry after 18Z. A much drier airmass will build into the region in the wake of the front late Wednesday. Precipitable water values will drop to less than half an inch by 03Z Thursday. Highs on Tuesday in the upper 70s to lower 80s. Cooler air will work into the region Wednesday night with lows in the middle to upper 40s. && .LONG TERM /THURSDAY THROUGH MONDAY/... High pressure will ridge into the region Thursday through Saturday providing dry conditions. Temperatures on Thursday and Friday will be much cooler than in recent days with highs in the lower 70s. Good radiational cooling will promote overnight lows in the middle to upper 40s. Moisture will return to the area late Saturday and Sunday as an upper trough digs into the Plains. The chance of rain will increase late in the weekend through early next week. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... VFR overnight into Tuesday morning, then deteriorating conditions during the afternoon Tuesday and Tuesday night. Frontal boundary stalled to our south. Upper energy will roll eastward across the southern tier of states Tue/Tue nt, leading to a surface wave developing and moving east, ahead of which isentropic lift will spread rain into our region. Some discrepancy in the models with regards to timing, but it generally appears that some light precipitation will move in during the morning, with precipitation becoming heavier and more widespread during the afternoon into Tuesday night. Expect deteriorating CIGs/VSBYs in response, with the lowest restrictions after 00Z Wed. EXTENDED AVIATION OUTLOOK...Widespread rain and associated IFR conditions Tuesday night. Clearing Wednesday with breezy conditions in the afternoon. Dry conditions Wednesday night through Friday. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None.