Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
320 FXUS62 KCAE 171943 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 343 PM EDT Mon Jun 17 2024 .SYNOPSIS... High pressure, drier conditions, and near normal temperatures are expected through late this week. Unsettled conditions are possible by late in the week into the weekend as moisture moves in from the Atlantic. Well above normal temperatures are expected by Saturday and Sunday. && .NEAR TERM /THROUGH TONIGHT/... Plenty of low level moisture and stratus this morning has mixed out and continues to transition into cumulus. Satellite imagery shows developing cumulus with a few showers in the CSRA. Expect these to move out in the next hour or two and remain relatively light. With sunset the cumulus will dissipate with partly cloudy skies persisting overnight. Some patchy fog is possible near daybreak however much is expected to be mitigated by the remaining clouds. High temperatures this afternoon remain on track for the upper 80s to low 90s with lows tonight in the upper 60s to around 70. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... The region will be positioned along the southern periphery of a strong high pressure ridge centered over New England and the northern Mid Atlantic Tuesday and Wednesday. At the surface, an onshore flow off the Atlantic will prevail. Despite the onshore flow, deep layered moisture will be lacking. Looking at the forecast soundings very little deep moisture to mention any isolated shra/tsra. Long range ensemble mean precipitable water values are around 1 inch on Tuesday and 1-1.25 inches on Wednesday, well below normal for this time of year. Given the dry atmosphere and subsidence aloft, expect rain-free conditions during the short term period. Temperatures will be slightly moderated some by the cooler onshore flow. Therefore, this period will likely consist of the coolest temperatures of the week, with seasonable highs in the upper 80s to around 90. && .LONG TERM /THURSDAY THROUGH MONDAY/... Strong upper level ridging will begin to sink south across the Mid-Atlantic and Carolinas Wednesday afternoon through Friday. The upper level ridging will shift west of the area by later Friday into the weekend. Operational long-range models and to some extent long-range ensembles suggest an inverted upper trough retrograding toward the southeast US coast on Friday beneath the strong ridge. While the signal has been weakening with recent model runs, there is the potential for a trough or area of low pressure to develop offshore and move toward the southeast US coast Friday into Saturday. The latest NHC 7 day Tropical Weather Outlook indicates a 30% chance of tropical formation. Despite any potential tropical development, there does appear to be at least a notable increase in moisture across the area supportive of unsettled conditions in terms of diurnal convection on Friday and to a lesser extent on Saturday. Ensembles then support strengthening ridging at the surface and aloft over the western Atlantic later Saturday and Sunday. However, by early next week a weakness develops over the Great Lakes and a s/w trough will move just north of the area across the OH Valley and Northeast. This will lead to well above normal temperatures over the weekend. In fact, the long range ensemble forecast shows the probability of temperatures reaching or exceeding 100 degrees to be 25-35% by Sunday. The NWS HeatRisk also shows Category 3/Red conditions across much of the area on Sunday, indicating a potential Major Risk of heat- related impacts. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR conditions expected through the period with low potential for early morning fog and stratus. Cumulus and a few showers around AGS/DNL will continue over the next couple hours. Have included a TEMPO for showers in and around AGS/DNL through 20z. With sunset cumulus will diminish with partly cloudy skies overnight. The clouds will suppress fog development so not mention of fog ATTM. Winds will remain easterly at 7 knots or less through early tonight then become light and variable finally returning to easterly around 8 knots from 15z through the end of the period. EXTENDED AVIATION OUTLOOK...Moisture and chances of showers and thunderstorms and associated restrictions return Friday and Saturday. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$