100417 Forecast

Mountain Area Forecast ( October 4-7 )

An Autumn Cold Front And Developing Tropical System Are Being Monitored For Possible Impacts Upon The Mountain Region By Later This Weekend  Into Early Next Week ( October 8-10 )

Details on this setup are yet to be worked out, with the Tuesday night run of the operational European Model trending east to keep significant rains along and east of the mountains ( from the Blue Ridge east to southeast ).  This is in contrast to the U.S. GFS Model, and most hurricane models, which track the tropical system much farther west.  Timing of an approaching cold front and upper air trough will help determine where the tropical system goes and how any linkage between it and the frontal zone develops.

A shot of unseasonably cool air will likely follow whatever happens with this tropical system by the middle of next week.  Stay tuned for updates.

Overnight Into Wednesday Morning

Mostly clear.  Light winds, except SSE-SSW at 5-10 mph, with some higher gusts, on mid-upper elevation mountain ridges.  Large vertical temperature spread between colder mountain valleys and milder ridges.  Temperatures varying from upper 20s to middle 30s in colder valleys to the upper 40s to lower-middle 50s on exposed ridges-plateaus.  Areas of fog along major rivers.

Wednesday Afternoon

Mostly sunny.  Light winds.  Temperatures varying from mid-upper 60s in upper elevations to the mid-upper 70s.  Warmer south into the Great Valley and river valleys.

Wednesday Night Into Thursday Morning

Mostly clear.  Light winds.  Large vertical temperature spread between colder mountain valleys and exposed ridges and plateaus.  Temps varying from 30s in the colder valleys to the lower-middle 50s on exposed ridges-plateaus.  Areas of river valley fog.

Thursday Afternoon

Mostly sunny ( some high clouds ).  Light northerly winds.  Temperatures varying from 60s in upper elevations to the mid-upper 70s ( warmer south into the Great Valley ).

Thursday Night Into Friday Morning

Mostly clear.  Light winds.  Large vertical temperature spread between colder valleys and exposed mountain ridges and plateaus.  Temperatures varying from 30s to lower 40s in colder mountain valleys to the low-mid 50s on exposed ridges and plateaus.

Friday Afternoon

Partly-mostly sunny ( high clouds ).  Unseasonably warm.  Light southerly winds.  Temperatures varying from upper 60s to lower 70s in upper elevations to the upper 70s to lower 80s ( warmer south into the Great Valley ).

Friday Night Into Saturday Morning

Partly-mostly clear ( high clouds possible ).  Becoming gusty higher elevations.  SSE-SSW winds increasing to 10-20 mph, with higher gusts, into the overnight-morning.  Temps from 40s in cooler mountain valleys ( sheltered from winds ) to mid-upper 50s to around 60 degrees on exposed middle-upper elevation mountain ridges and plateaus.

Reference My Latest Hellbender-Cloudsplitter Forecast section for details related to the race days of October 7-8.
Reference Mid-Autumn 2017 In The High Knob Massif for more views of conditions observed at the end of September.


Weather Discussion ( Harvest Moon )

The first full moon closest to the Autumnal Equinox is always called the Harvest Moon, for times when farmers and Native Americans used moonlight to gather in late season crops.  Although not quite full yet, the moon early  on October 4 was getting close in the chilly air filling mountain valleys of the Cumberland Mountains.

Harvest Moon Above The Cumberland Mountains – October 4, 2017

While it is looking to be unseasonably warm and continued dry for the High Knob Hellbender 10K race on Saturday, the second day of the Cloudsplitter 100 is more uncertain and will depend upon what happens with a developing tropical system in the Gulf of Mexico.

Changing Seasons In The High Knob High Country

Ensembles of the GFS Model have been farther west than the mean of the 51-Member European Model group.  Right now the bulk of hurricane models are also farther west.

Hurricane Spaghetti Model Track Forecast – 8 PM Tuesday Run ( Oct 3 )

I think the setting will become more clear once hurricane hunter data and other data being collected gets put into the models during the next couple of days.  A track like above would tend to spread heavy rain across all of the southern-central Appalachians, while a track like the current run of the Operational European Model would keep heavier rains mainly along and east of the Blue Ridge.