Area Forecast Discussion
Issued by NWS Greer, SC

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000 FXUS62 KGSP 162015 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 315 PM EST Sun Dec 16 2018 .SYNOPSIS... Drier air associated with broad high pressure will spread over the region today and tomorrow and linger through midweek. Another low pressure system is then expected to develop to our west and bring widespread precipitation to the region for Thursday and Friday. && .NEAR TERM /THROUGH MONDAY/... As of 245 PM EST Friday: Upper low continues to swirl just off the Mid-Atlantic coast and push off to the northeast this afternoon, as seen from latest satellite imagery, with NW flow continuing to infiltrate into the western Carolinas behind the exiting system. Across the NW Piedmont and Upstate SC, conditions have remained fairly quiet today with plenty of sunshine allowing for temperatures to climb above normal. As for areas along the TN/NC border, a mix of cloud cover and isolated light showers has prevailed with low level moisture lingering over the TN and OH valleys and additional upslope forcing as a weak upper SW continues to move overhead. As this available moisture source decreases overnight, expect cloud cover and isolated precipitation to decrease as well. Would not completely rule out a few snowflakes mixed in, especially along the higher ridges, though do not expect any snow accumulation. Overnight, with clear skies outside the mountains and gradually clearing skies along the TN/NC border, overnight low temperatures are expected to dip into the 30s, remaining in the mid to upper 30s across the NW Piedmont and Upstate. With residual saturated soils, could not rule out patchy areas of fog towards morning. Though lingering weak troughing looks to remain over the area on Monday as upper ridge continues to build over the central US, conditions are expected to remain dry and quiet with plenty of sunshine, maybe some passing thin cirrus. Temperatures along and south of the I-85 corridor will warm into the low 60s, back into the upper 50s towards the escarpment, and slightly cooler across the mountains. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... As of 140 PM EST Sunday: Quiet weather persists in to the short term with weakening broad northwesterly flow aloft Tuesday transitioning southwesterly well in advance of the late weeks system which will begin organizing across the Southern Plains by Wednesday. Can`t rule out some patchy fog under mostly clear skies Tuesday morning. Otherwise, expect increasing mid to high level clouds as early as Tuesday night, but more likely Wednesday. Seasonal temperatures are expected through the period. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As of 315 PM EST Sunday: Model guidance is gradually coming into better agreement with the storm system for late in the work week. A strong 150+ mph jet streak is expected to dive down into the west side of the trough over the southern plains Thursday as is continues its trek towards the deep south. Increasing upper level divergence aloft on the cyclonic side (east side) of the trough will fuel fairly rapid intensification of the surface reflection of the cyclone as it moves roughly along or just west of the Appalachians into the eastern Great Lakes Thursday into Friday, before pressing further into southeast Canada. The net result will be increasing and lowering clouds across the forecast area early in the day on Thursday before increasing south to southeasterly flow over weak insitu damming brings increasing rain chances from south to north Thursday afternoon and evening and continuing overnight. The latest guidance indicates that a developing warm sector may push into the region Thursday evening or night, scouring out any remaining insitu damming. There are even signs that some thunderstorms may be severe (low CAPE, high shear). However, this potential will be highly dependent on the eventual track of the sfc low and erosion of any in- situ damming in place. As a result of the uncertainty this far out, have limited thunderstorms just before mentionable levels for now to match surrounding offices. Developing northwest flow (gusty across the mtns) on the back side of the system will likely bring continued shower activity focused across the NC mountains near the TN border Friday. Much uncertainty remains for this portion of the forecast, although accumulating snowfall is possible, especially across higher elevations. Things will dry out over the weekend with a return to mostly sunny skies. Near to below normal temperatures are expected Thursday through Saturday, possibly moderating to above normal, especially east of the mountains Sunday as cold air advection relaxes under mostly sunny skies. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... At KCLT and elsewhere: Despite lingering cloud cover and isolated drizzle/showers along the TN/NC border, VFR prevails at all TAF sites this afternoon as intermittent thin cirrus pass overhead. Expect conditions to remain quiet through the overnight hours, though would not entirely rule out patchy MVFR fog towards daybreak, especially across the Upstate and NW Piedmont, where soils remain saturated. However, given low confidence, have not introduced into going TAF fcst attm. With NW winds currently at KAVL, elsewhere, winds will continue to veer from the SW to NW through this evening, with sustained winds 5 to 10 kts. Given CAA, intermittent gusts, especially at KAVL and KHKY are possible through this evening. On Monday, expect VFR to prevail with SKC/FEW250 and WNW winds 5 to 8 kts. Outlook: A wet low pressure system looks likely to bring restrictions Thursday, perhaps lasting into Friday in some areas. Otherwise, expect VFR. Confidence Table... 20-02Z 02-08Z 08-14Z 14-18Z KCLT High 100% High 100% High 100% High 100% KGSP High 100% High 100% High 100% High 100% KAVL High 100% High 100% High 100% High 100% KHKY High 100% High 100% High 100% High 100% KGMU High 100% High 100% High 100% High 100% KAND High 100% High 100% High 100% High 100% The percentage reflects the number of guidance members agreeing with the scheduled TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables and ensemble forecasts are available at the following link: www.weather.gov/gsp/aviation && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...JPT NEAR TERM...SGL SHORT TERM...Munroe LONG TERM...Munroe AVIATION...SGL

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