Sugar Mountain

Summary

SYNOPSIS

... Strong storms are possible thru this evening southeast of Interstate 85. Dry high pressure will keep most areas dry through the weekend, with mild temperatures. An unsettled pattern will take shape late Monday, with rain chances returning and lasting through Wednesday.

NEAR TERM /THROUGH TONIGHT/... As of 135 AM: Winds have diminished for all but the higher elevations with stratocu lingering across the mountains. That said, some gusty Gap wind may continue early this morning.

Drier air overall will be over the area today. However, a weak cold front moves into the mountains by afternoon. Guidance shows enough moisture and weak instability moves in with this system for isolated to scattered showers mainly across the NC mountains during the late afternoon and early evening. Some of the guidance shows the potential for a few of the SHRA to break containment and move out of the mountains and southeast across the area. Chance remains quite low with the guidance blend washing the chances out. Have kept the forecast dry outside of the mountains for now. Winds increase through the day with gusty winds across the mountains and possible elsewhere, but with lower magnitudes than on Friday. Highs will be a few degrees below normal with comfortable dew points.

Shower chances taper off during the evening with dry conditions and clearing skies overnight. Winds taper off outside of the mountains during the evening then across the mountains overnight. Lows will be around 5 degrees below normal.

SHORT TERM /SUNDAY THROUGH MONDAY/... As of midday Friday: Confluent upper flow between NE CONUS closed low, and a ridge in the lower MS Valley, will allow dry sfc high pressure to build into the CWA beginning Saturday night. This looks to suppress diurnal convection Sunday. Mild, near-normal temps, fairly low humidity, and light winds look to make for a nice Mother's Day.

Ridge will migrate east and sfc high will set up just off the East Coast by Monday morning. Southerly flow will develop atop it within moisture plume on warm side of occluded low moving into the Ozarks; surface front still looks likely to be well south of the CWA. Models vary in how quickly they develop precip; some do so Monday and others Monday night. The setup could foster in-situ CAD once precip develops. With increased cloud cover temps Monday should be a little cooler than Sunday.

LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 200 PM Fri: Low pressure will track into the lower Ohio Valley Tuesday, and PWATs will peak that afternoon or early evening as southerly moisture flux comes to a head in advance of the low. Main shortwave trough likely will be centered over west-middle TN during the afternoon, but some degree of DPVA could be present to further enhance lift. How well CAD becomes entrenched may be critical, as by the same token SBCAPE could creep into our lower Piedmont. GFS soundings are rather skinny and not indicative of much more impact than convectively enhanced rainfall rates. Per NAEFS and EPS member soundings, a few hundred J/kg could overlap with around 40 kt of deep layer shear, so a strong to severe thunderstorm is not completely out of the question. That said, leaned slightly toward the low end of guidance given potential CAD. Tuesday likely will be the coolest day of the week with highs in the mid-70s, but if CAD does form highs may stay in the 60s.

Low-level flow will turn westerly and some upslope driven precip is possible Tue night into Wed near the TN border. The shortwave itself will cross the CWA Wednesday morning. Temps will rebound above normal for Wed with skies clearing and downslope winds east of the mountains. Gradient aloft will be weaker and near-sfc winds more veered, so less shear will be present but stronger CAPE. As such scattered t-storms look somewhat more likely but severe threat probably lesser. Precip chances diminish Wed night as another ridge moves overhead behind the shortwave. Dry weather will last until the next low approaches from the west and warm front lifts over the area. That currently looks likely to occur Thursday night or Friday, but as a nod to the few solutions depicting it earlier, PoPs tick upward again Thu afternoon. Thursday temps also will be a little above normal.