Area Forecast Discussion
Issued by NWS Greer, SC

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619 FXUS62 KGSP 012358 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 758 PM EDT FRI JUL 1 2016 .SYNOPSIS... An upper trough will push a cold front south across the region through Saturday. The front will stall just to the south of the area, but then will lift slowly back north late in the weekend into the beginning of next week. && .NEAR TERM /THROUGH SATURDAY/... As of 750 PM: A few cells have redeveloped over the srn NC Foothills over the past hour, though none have yet grown tall enough for lightning. These likely formed along some sort of convergence axis or other local boundary, tapping instability that was not realized during the day when LCLs were higher. Meso model runs would suggest these are the last cells of the day, but seeing how much CAPE developed this afternoon, any outflow they produce might fire up a new isolated cell over the next hr or two in the Hwy 221 corridor. As a weak upper trough exits the region tonight, drier air already in place over the northwest zones will certainly try to make it farther south, but as the flow flattens tonight the front will stall across the area making the attempt of dry air intrusion futile across most of the Piedmont, with not much change in overnight lows from what we`ve been seeing. The front will sort of stall and then wash out across the area Saturday, and with a shortwave approaching from the west (more on that below), should see a decent increase in instability across the area with just a bit of an enhancement to the normal summertime diurnal pattern, with initial convection over the mountains but possibly increasing in coverage across the NC Piedmont in closer proximity to the upper forcing. Thermodynamics tomorrow look similar to today but with just slightly stronger flow aloft could see a bit of jet-level synoptic lift, and thus the SPC Day2 Marginal Risk for eastern zones looks reasonable. Highs Saturday are progged to be a degree or two warmer than those today. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 230 pm EDT Friday: Mid level ridging will be in place to the south of the area through this period, keeping conditions warm and muggy. The southern end of the westerlies will allow weak disturbances in the flow to kick of mainly afternoon and evening showers and thunderstorms. As usual, initiation will begin across the higher terrain then pushing into the Piedmont during the late afternoon and evening. High temperatures will be in the lower 90s outside the mountains with heat indices reaching the mid to upper 90s each afternoon. Lows will likely remain above 70 degrees outside the mountains. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 230 pm EDT Friday: Weak troffing will develop during this period across the region allowing for a general increase in shower and thunderstorm activity. The peak in the activity will be in the typical late afternoon/evening but overnight activity should increase during the period as well. Conditions will remain hot and muggy with heat indices approaching 100 outside the mountains before storms cool it off each day. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... At KCLT and elsewhere: VFR expected tonight at the TAF terminals, but outlying areas might see some patchy and shallow fog. Low cigs are not expected to develop either, given low-level winds veering to westerly or northwesterly in the predawn hrs, and the fact that there was so much less convection Fri aftn compared to the previous two aftns (recall low clouds plagued the sites the following mrngs). Winds veer around as noted, being NE-ly after daybreak and southerly in the aftn, except at KAVL where the usual channeling will occur. Characteristically unstable conditions are likely to redevelop Sat aftn; TS chances are in the PROB30 range over western NC and too low to mention over SC. Outlook: A weak frontal boundary stalls across the region Sunday, and persists into the middle of next week. Afternoon/evening showers and thunderstorms will continue, and restrictions could occur the following morning wherever heavy rain falls in the afternoon. A wave of low pressure moving east along the boundary will enhance TSRA potential Mon-Tue. Confidence Table... 00-06Z 06-12Z 12-18Z 18-00Z KCLT High 100% High 100% High 97% High 100% KGSP High 100% High 100% High 100% High 100% KAVL High 100% High 97% 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 schedule TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables and ensemble forecasts are available at the following link: && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...SW NEAR TERM...TDP/Wimberley SHORT TERM...SW LONG TERM...SW AVIATION...Wimberley is the U.S. government's official web portal to all federal, state and local government web resources and services.