textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Updated for 12Z aviation discussion.

KEY MESSAGES

1. The remnants of Isaias will move northeast into the Central Appalachians today. A cold front extending south from the remnant low will sweep across the area today bringing an end to the widespread showers. Until then, heavy rain additional heavy rain, along with an isolated thunderstorm will move through. Gusty winds continue as well. 2. Gusty northwest winds expected across the higher elevations tonight through Monday as a drier airmass builds back into the region. After that, dry weather with a warming trend into the middle of next week.

DISCUSSION

Key message 1: The remnants of Isaias will move northeast into the Central Appalachians today. A cold front extending south from the remnant low will sweep across the area today bringing an end to the widespread showers. Until then, heavy rain additional heavy rain, along with an isolated thunderstorm will move through. Gusty winds continue as well.

Post-Tropical Cyclone Isaias is now centered over middle TN and will move into the Central Appalachians today. A cold front extending south from the remnant low will sweep across the area and move to our east by afternoon. Ahead of the front, widespread showers and isolated thunderstorms will continue. Additional heavy rain will be associated with this convection, keeping ongoing flooding in place and potentially creating new flooding. Elevated instability ahead of the front will keep the potential for isolated thunderstorms in the forecast. Low level shear remains high, so any storm that can tap the instability and shear, could become severe and possibly creating a brief tornado. The good news is all this is occurring during the more climatologically unfavorable morning hours. The better chances of severe storms will be to our east, but of course, we'll keep an eye on any storms. The Flash Flood Watch will remain in place until the heavier showers move east.

Winds have diminished but low end gusty SE winds will continue ahead of the cold front. The winds turn SW and remain gusty behind the front, eventually turning NW across the mountains. Winds diminish outside of the mountains during the evening but gusty winds linger across the mountains.

Although clearing takes place behind the front, some lingering moisture and the developing upslope northwesterly winds will keep scattered showers in the counties along the TN border. This will have light QPF and should not cause any additional flooding.

Key message 2: Gusty northwest winds expected across the higher elevations tonight through Monday as a drier airmass builds back into the region. After that, dry weather with a warming trend into the middle of next week.

Wind gusts of 25-35 mph are expected to redevelop across the mountains, gradually tapering off Monday. Otherwise, a developing upper ridge will maintain dry weather for most of the work week, with light winds and temps trending well above normal Tue-Thu. A cold front late in the week should bring temperatures back near or below normal.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

At KCLT and elsewhere: Convection along the cold front will move east of the area early this morning. IFR ahead of the front becomes MVFR behind. SE wind ahead of the front becomes SW and gusty behind it. Expect low VFR and/or scattering out during the afternoon. Gusts diminish in the evening with a more WSW direction. KAVL sees a turn to the NW for the afternoon with gusts developing. MVFR cigs may linger there into the evening or even overnight.

Outlook: VFR with gusty NW wind on Monday. VFR outside of mountain valley fog Tuesday and Wednesday, with light winds. A backdoor cold front could bring light precipitation and restrictions Thursday.

GSP WATCHES/WARNINGS/ADVISORIES

GA...Flood Watch until 2 PM EDT this afternoon for GAZ010-017-018- 026-028-029. NC...Flood Watch until 2 PM EDT this afternoon for NCZ033-049-050- 052-053-059-062>065-501>510. SC...Flood Watch until 2 PM EDT this afternoon for SCZ010>012-019- 101>109.