Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
985 FXUS62 KCAE 180232 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 1032 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 /UNTIL 6 AM TUESDAY MORNING/... Additional convection unlikely in the near term with a nocturnal inversion and ridging aloft creating a stable air mass. Southeast low level flow could promote fog or stratus during the early morning hours. A 15 to 20 kt LLJ should favor stratus over fog. Lows will be in the mid to upper 60s. && .SHORT TERM /6 AM TUESDAY MORNING 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 /02Z TUESDAY THROUGH SATURDAY/... VFR forecast. High pressure centered along the Mid Atlantic coast will extend southwest across the area. Low pressure is developing in the Gulf of Mexico. Southeast winds 5 to 10 knots will diminish by 03z. The models are suggesting drier air along the Carolina coast will spread inland overnight. Surface dew points are expected to fall through Tuesday. This suggests a low fog threat toward morning. Also, the guidance is consistent with no stratus overnight with the low-levels drying toward morning. Some mid and high clouds are spreading northeast from the Gulf coast region into South Carolina, with most of the mid level clouds remaining near the AGS/DNL terminals along the Savannah River. Subsidence under an upper ridge over the area and drier air suggest any cumulus Tuesday afternoon will be quite limited. The pressure gradient will be tightening a bit Tuesday so expect east-southeast winds 10 to 15 knots with a few gusts near 20 knots in the afternoon. 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. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION...