Area Forecast Discussion
Issued by NWS Greer, SC

Home |  Current Version |  Previous Version |  Text Only |  Print | Product List |  Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
398 FXUS62 KGSP 200215 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 1015 PM EDT Wed Jun 19 2024 .SYNOPSIS... High pressure atop the region will suppress any storms from developing this week until moisture returns on Saturday. A heat wave gets underway on Friday and remains hot through the start of next week. A weak cold front approaches from the north early next week but is expected to stall out then dissipate. && .NEAR TERM /THROUGH THURSDAY/...
-- Changed Discussion --
As of 1000 PM: A stripe of a stthicker cirrus can be seen on the nighttime RGB product over the Southern Appalachians. These clouds may be slowly the radiational cooling somewhat, but overall, skies should be mostly clear with varying amounts of cirrus overnight. With previous update, did add a little more fog mention, given the forecast lows in the mountain valleys are a few degrees below the current sfc dewpts. The rest of the forecast looks on track. Otherwise...Upper anticyclone and attendant ridge will remain west-through-north of the forecast area, with deep easterly flow expected through much of the period. The low level flow is expected to weaken tomorrow, as surface high sags south and weakens across the western Atlantic...and a weak easterly wave approaches the Southeast Coast. This should result in a slight warm-up of 1-2 degrees on Thursday afternoon. Min temps will otherwise again fall to near-normal levels thanks to the relatively dry air mass. Said air mass will continue to limit diurnal instability to meager-at-most levels, with little-to-no chance of afternoon/evening convection through the period.
-- End Changed Discussion --
&& .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... As of 142 PM EDT Wednesday: The week should end with typical summer heat that starts to build into the weekend. A breakdown of sorts in the large eastern upper anticyclone should be complete by Friday, with one center migrating to the TN Valley region and other offshore, separated by a weakness brought on by a weak easterly wave that runs into the Southeast Coast. Although this might suggest some increase in precip potential, especially Saturday, the model guidance keeps that potential near the coast, in part because of how strong the cap remains in place across our region through Saturday, even over the higher terrain. The upshot is that we stay relatively dry as sfc high pressure lingers over the region. That makes the high temps the main concern, although merely normal on Friday, but then creeping up a few degrees above normal into the middle 90s in places east of the mtns. Be that as it may, the humidity will not be high enough to raise the heat index more than a deg or two above the air temp, so no big problems yet. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... As of 222 PM EDT Wednesday: The second half of the weekend looks like a quick transition aloft as the old upper anticyclone to our west breaks down further and the center retrogrades to the Southwest on Sunday, while in its place a cyclonic flow aloft is introduced by a northern stream system moving across the Great Lakes to eastern Canada/New England through Monday. At a minimum, the pattern shift favors a return to at least climo precip probs starting on Monday, but the mid-upper troffiness lingers into the middle of the week, suggesting less of a diurnal dependence to the convection and more potential for a shower/storm at any time of the day. The expectation is for the region to finally get into a more pulse-severe type regime. A thermal ridge will remain, allowing temps to climb about five degrees above normal each day, while an increase in the humidity will finally allow the heat index to climb upwards toward more uncomfortable values, but perhaps not yet into Heat Advisory range. Because this should be our first real hot weather of the season, it still warrants a mention in the HWO east of the mountains. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... At KCLT and elsewhere: VFR conditions are expected thru the period, but some mountain valley fog may form overnight (not expected to affect KAVL, but cannot be entirely ruled out). Little change in the pattern for Thursday, with dry high pressure in control. Light ENE to ESE wind expected at the Piedmont sites, and SE at KAVL. Periods of thick cirrus, with another fair wx cu field forming late morning thru the aftn with VFR-level bases. Outlook: An expansive upper ridge will keep things mostly dry with VFR conditions thru Friday. Mountain valley fog and/or low stratus will be possible each morning. Isolated diurnal convection in the mountains possible Saturday, then a return to more scattered convection across the region Sunday and Monday. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...ARK/JDL SHORT TERM...PM LONG TERM...PM AVIATION...ARK