070717 Forecast

Mountain Area Headlines ( July 7-9 )

1 ).  A Mesoscale Convective System will drop south to southeast toward the mountains Friday Night into the early hours of Saturday.  While a weakening trend is expected, strong to locally severe thunderstorms will remain possible as this cluster of storms approaches the Cumberland Mountains.

HRRR Model Future Doppler Radar Forecast At 1:00 AM Saturday – July 8, 2017

The main storm threats are damaging winds, lightning and heavy rainfall.  This system is expected to weaken across the higher mountain terrain overnight.

2 ).  Rain cooled outflow from this system & approach of a surface cold front will trigger new development from the morning into afternoon hours of Saturday.

JKL Doppler At 9:27 PM Friday – July 7, 2017
An outflow boundary just north of Jackson, Ky., at 9:27 PM is starting to move out ahead of the MCS, indicating a trend toward  weakening during coming hours.  Any left-over boundaries + the surface front will bear watching for new development following onset of day-time heating Saturday.

3 ).  Drier, less humid and more stable air is expected to overspread the mountains from northwest toward southeast by late Saturday afternoon into Sunday.

Lower dewpoints will make conditions feel much better from Saturday Night through Sunday Night, with notable cooling within mountain valleys ( MINS in the 50s will be widespread across the area, with coolest valleys dropping into the 40s to contrast with upper 50s to low-mid 60s on exposed mountain ridges Sunday & Monday mornings ).

4 ).  A ring-of-fire pattern will become possible next week around the periphery of a building heat dome with rising day-time temperatures early next week.

European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 4-8

A modeling trend ( ensemble mean ) is for a heat dome to set up near the Red River Valley & Texas-Oklahoma panhandles next week.  This will generate a WNW-NW flow pattern and ring-of-fire convective regime ( i.e., clusters of showers and thunderstorms will develop along the edge of the hottest air and move around the periphery of the heat dome ).

European 51-Member Ensemble MEAN 500 MB Height Anomalies: Days 6-10

The eventual location of the heat dome core will need to be followed, along with the recent dry feedback tendency that has generated below average rainfall across portions of the mountain region during June-early July ( local wet feedback has also been observed as typical of patterns featuring hit-miss convective development & movement ).