100516 Forecast

Mountain Area Forecast ( October 3-5 )

Overnight Into Monday Morning

Partly to mostly clear.  Areas of dense fog.  Light N to NE winds mostly less than 10 mph on mid-upper elevation mountain ridges.  Temperatures varying from the low-mid 40s in upper elevation valleys to the low 50s.

Monday Afternoon

Partly cloudy.  Light NE-ENE winds.  Temperatures varying from upper 50s to lower 60s in upper elevations to the low to mid 70s.

Monday Night Into Tuesday Morning

Partly-mostly cloudy.  Areas of dense valley fog.  Winds becoming ESE-SSE at 5-15 mph, with higher gusts, along middle-upper elevation mountain ridges.  Temperatures varying from the 40s in cooler mountain valleys to mid-upper 50s.

Tuesday Afternoon

Partly-mostly cloudy.  Small chance of a rain shower.  Winds SE to SSE at 5-10 mph, with higher gusts.  Temps varying from low-mid 60s in upper elevations to the mid 70s ( warmer, every day, as usual into the Great Valley ).

Tuesday Night Into Wednesday Morning

Partly-mostly clear.  Areas of valley fog.  Winds SE-SSE 5-15 mph, with higher gusts, on mid-upper elevation mountain ridges.  Temperatures varying from 40-45 degrees in colder mountain valleys to the low-middle 50s.

Wednesday Afternoon

Mostly sunny.  Winds E to NE at 5-10 mph.  Temperatures varying from low-mid 60s in upper elevations to the mid-upper 70s.

Chilly temperatures are expected into Thursday AM with low dewpoint air developing beneath subsidence and drying north of Hurricane Matthew.  MINS are forecast to vary from the 30s to lower 40s in colder mountain valleys to the mid-upper 40s.

 

Weather Discussion ( Mostly Dry )

Some light showers and sprinkles fell upon the high country of the High Knob Massif during Sunday PM, of October 2, as MAX temperatures climbed to around 60 degrees ( from AM MINS in the mid 40s ).

Changing Autumn Colors at Big Cherry Lake
Changing Autumn Colors at Big Cherry Lake – October 2, 2016
Sections of upper slopes are developing significant color changes while lower slopes, below 2700-3000 feet, remain mostly green.
Color Changes In Big Cherry Lake Basin
Color Changes In Big Cherry Lake Basin – October 2, 2016

October 2016 opened foggy and chilly in high valleys, with low temperatures dipping to around 40 degrees in the basin of Big Cherry Lake ( the lowest temps reported in Virginia ).

High Valley of Big Cherry Basin
High Valley of Big Cherry Basin – Opening To October 2016

Following mid 50s to lower 60s during the afternoon of October 1, in wake of the High Knob Hellbender 10K Race, skies became mostly cloudy into Sunday and eventually produced ( as noted above ) some sprinkles-light showers.

NAM 12 KM Model Total Precipitation Forecast
NAM 12 KM Model Total Precipitation Forecast To 8 AM Thursday – October 6

While a few rain showers can not be ruled out, especially into Tuesday ( October 4 ), most of the week will again be devoid of any significant rainfall.  In fact, the most recent run of the European Model says most of the next 10 days will remain generally dry ( save for a few showers ).

I measured a total of 0.68″ at Big Cherry Dam for the past week, which brought the September 2016 total to 3.40″ ( well below the average ) and the yearly tally to 51.48″ ( with missing moisture in evaporation between hand-measurements not being included ).
Model Composite Tracks For Hurricane Matthew
Model Composite Track Forecast For Hurricane Matthew

The main weather focus in the eastern USA this week will be on powerful Hurricane Matthew.  While the mean of all tracks remain off the Atlantic Coast, the exact track is far from set and all interests along the coast will have to keep watching this cyclone very closely.

While no direct impacts are expected locally, indirect effects will, as I so often teach, be observed in the form of sinking air that acts to rebuild and reinforce the upper ridging over the region to allow days to warm as the storm approaches ( this could allow nights to trend cooler in mountain valleys if drying around and below 850 MB occurs due to the general subsidence regime – especially along the western Appalachians ).
Model Cluster Forecast
Model Composite Track Forecast For Hurricane Matthew

A distinct and important westward trend in the composite of model forecast tracks for Hurricane Matthew has been observed during the past 18-hours ( compared the above graphic to the one issued at 2:00 AM or 06z on October 3 ).