Hit-Miss Tropical Downpours & Thunderstorms Will Continue Through Coming Days
Although the flash flood warning is no longer in effect, please use caution around swift running creeks and watch for ponding of water in low-lying places during the overnight into Tuesday morning.
Issued By Morristown NWSFO
A jungle-like high water content air mass will continue to grip the mountain region through the foreseeable future, with little relief from high humidity levels. A developing disturbance in northern portions of the Gulf of Mexico will be closely watched for possible impacts upon the southern Appalachians by mid-late this week.
Overnight Into Sunday Morning
Hazy & humid. Areas of dense fog. Chance of an isolated shower. Winds NW-NE winds 5-10 mph along mid-upper elevation mountain ridges. Temps in the 60s to near 70.
Sunday Afternoon
Partly-mostly cloudy. Humid. Chance of hit-miss showers & tropical downpours. Thunder possible. NE winds mostly less than 10 mph. Temperatures varying from lower 70s at highest elevations to the lower 80s ( hotter, as is typical, to the south toward the Great Valley and Tri-Cities ).
Sunday Night Into Monday Morning
Hazy & humid. Areas of dense fog. Chance of a shower, especially during the evening. Light winds. Temperatures in the 60s to near 70 degrees.
Monday Afternoon
Partly-mostly cloudy. Humid. Chance of hit-miss showers & tropical downpours. Thunder possible. ENE-ESE winds 5-10 mph. Temperatures varying from lower 70s at highest elevations to the lower 80s ( hotter, as is typical, to the south toward the Great Valley and Tri-Cities ).
Monday Night Into Tuesday Morning
Hazy & humid. Areas of dense fog. Chance of hit-miss showers ( especially along & S-SE of the High Knob Massif ). Winds SE to SSE 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges. Temps in the 60s to around 70 degrees.
Tuesday Afternoon
Partly cloudy. Humid. Chance of hit-miss showers and tropical downpours in thunderstorms. Winds SE-SSE 5-10 mph, with higher gusts, especially along middle to upper elevation mountain ridges. Temps varying from low-mid 70s at highest elevations to the lower-middle 80s ( hotter south toward the Tri-Cities ).
*A heavy to excessive rainfall potential, of a more widespread nature than recently observed, may develop for portions of the southern Appalachians late this week. Stay tuned for updates.
Weather Discussion ( August 1-9 )
A new month has brought little change in the weather pattern, with less heat but continued high humidity to make conditions steamy and uncomfortable.
A total of 24 of the past 38 days ( 63% ) have
featured measurable rain in the City of Norton.
National Weather Service Station at UVA-Wise – Observer Layton Gardner
Conditions in Wise and Clintwood have been very similar, despite the higher elevation in Wise, during the first 6 days of August due to tropical air ( high humidity ) over wet ground with rain falling every day ( although heavy downpours have been hit-miss with rainfall totals locally to 3.00″+ during August 1-6 ).
National Weather Service Station at Clintwood 1 W – Observer Wayne Browning
The only relief, in part, has been in upper elevations of the High Knob Massif where daily MAXS in low to mid 70s have been common at highest elevations ( still with muggy air ) where breezy conditions have helped to some extent.
Doppler Radar Rainfall Estimate For Saturday – August 6, 2016
Tropical downpours Saturday ( August 6 ) were widely scattered with main corridors extending from Coeburn across portions of the Little Stony Creek & Guest River gorges southeast to near the Mendota Lookout Tower, from High Butte southeast over the U.S. 23 corridor ( between MECC & Harvey ) into the Stock Creek Basin and from the Cranks Creek & Stone Mountain WMA’s southeast by Jonesville to northwest of Kyles Ford. Local downpours hit in the City of Norton and near Appalachia.
*Doppler radar tends to under-estimate rainfall totals in these tropical downpours, especially in orographic locations where rising air further adds to their intensity ( rates of rain fall ). This was observed during July across the High Knob Massif, and in the City of Norton, and has continued during this first week of August ( the weather pattern has been the same ).
Doppler Rainfall Estimate – Zoomed In View – August 6, 2016
Some changes begin to show up into mid week as air flow becomes more easterly. An easterly wind in summer often does not have the same effect as during winter, with heavy rain still remaining possible due to convection ( especially daytime instability ) northwest of the Eastern Continental Divide via abundant low-level moisture.
During the orographic forcing season strong air flow tends to dry lower-levels northwest of the Eastern Continental Divide to reduce total rainfall amounts. Strong air flow is generally lacking during the convective season, outside of organized tropical systems that move inland with enhanced pressure gradients to increase winds, such that forecaster’s have to be more cautious ( especially during summers that feature obvious wet feedbacks ) given much more abundant low-level moisture to feed convection.
Throughout the year there also tends to be a secondary zone of enhanced precipitation on easterly air flow trajectories along the east-southeastern side of the High Knob Massif as noted in recent days with heavy rains over northern Scott County ( heavier than was forecast in much of the Flash Flood Watch zone to the east ).
NAM 12 KM Model Total Precipitation Forecast Next 84-Hours
The upcoming extended forecast period will be one to watch as the MEAN of the 51-Member European Ensembles shows a distinct weakness, or break, in the heat ridges that could allow deep, tropical moisture to spread across the region.
European 51-Member Ensemble MEAN 500 MB Height Anomaly Forecast
Southwest North Carolina ( e.g., Lake Toxaway, Highlands, Brevard ) is certainly most favored for excessive rainfall as deep moisture flows north from the Gulf of Mexico, as are eastern slopes of the Blue Ridge, but it can not be ruled out for locations from the Tennessee Valley back across the already wet Cumberland Mountains ( where it would not take as much to cause problems in the Cumberlands ).
