Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
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916 FXUS62 KGSP 290458 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 1258 AM EDT Mon Apr 29 2024 .SYNOPSIS... The warming trend will continue through mid week as high pressure remains centered just off the Atlantic Coast. A weak cold front is expected to move through the area on Tuesday bringing scattered showers and thunderstorms. A stronger front is expected to approach the Carolinas by late week and bring more showers and thunderstorms to the area. && .NEAR TERM /THROUGH TODAY/... 100 AM Update...No sigfnt changes to the going fcst. An off-shore sfc high continues to ridge across the area making for dry conds outside of an area of low clouds across the srn BR escarpment. These clouds will linger and become a little more widespread thru the morning as upslope flow continues. Not a great fog threat this morning as the sfc-layer decouples yet remains weakly mixed and relatively dry. However, cold air drainage will likely instigate fog development, possibly dense, across the Little TN Valley within the sw/rn NC mtns. Otherwise, heights will fall across the region during the near term...especially the latter half of the period, as upper ridge axis progresses to the East Coast...downstream of a trough axis advancing east of the Miss River on Monday. As deep layer ridging moves east of the area tonight into Monday, low level flow is forecast to become increasingly SW, which is expected to result in less cloud cover tonight into Monday. Decent radiational cooling conditions should follow tonight, and min temps are expected to cool to just slightly-above-climo. Elevated near-surface moisture could allow for some patchy fog development, particularly in the climatologically favorable locations in the mountain valleys. Sunnier conditions combined with increasing thickness values should allow max temps on Monday to warm to around 5 degrees above normal. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... As of 1:45 PM EDT Sunday: Upper ridge over the East Coast will still be in place as we move into the short term, with the trough that has been causing all the problems in the Southern Plains lifting and damping as it pushes east. Occluded front will approach the Appalachians at the start of the period, weakening on the southern end as it competes with the hefty ridge. Pops move into western zones before daybreak and ramp up during the afternoon hours, especially over the mountains, but the high elevations really tears the low level features of the front up. Very little deep layer shear to work with (not even 30kt collocated with the best instability) and even the more unstable NAM keeps SBCAPE less than 1000 J/kg. So for now, general thunder looks good, but can`t rule out that one or two may be stronger to marginally severe. Temps should be several degrees above normal on Tuesday with southerly flow still around the surface high off the Atlantic, even with the shortwave and front coming through. The shortwave passes through quickly and ridging builds right back in on the back edge. Under full sun, temperature will climb a few degrees higher for highs on Wednesday, probably a good 10 or so degrees warmer than seasonal normals. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As of 2:15 PM EDT Sunday: Upper ridge is still in place as we move into the extended Wednesday night into Thursday, with another shortwave diving out of the Rockies into the Plains. Increasing disagreement in how this system is handled in the global models, but general picture shows another front pushing across the center of the country Thursday and towards our area Friday. Should see another uptick in temperatures on Thursday as the ridge strengthens, with pops moving back in on Friday. For now this front looks a little stronger than the early-week front, at least as far as instability goes, so this will have to be monitored in case this trend holds in future runs. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... At KCLT and elsewhere: Surface ridging will dominate the pattern thru the TAF period and help make for VFR conds all sites. Low cloud development will be confined across the srn NC mtns, as LCLs remain quite dry. No big VSBY issue either thru the morning hours. Winds round the sfc ridge and align generally sw/ly to s/ly with low-end gust possible mainly at KAVL and KHKY this afternoon. Outlook: A frontal system could bring a round showers and storms to the area on Tuesday, with more of a potential for isolated diurnal convection on Wednesday and Thursday. The next front could bring better coverage of showers and storms on Friday. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...JDL NEAR TERM...AR/JDL/SBK SHORT TERM...TDP LONG TERM...TDP AVIATION...SBK