Hit-Miss Tropical Downpours & Thunderstorms Will Continue Through Coming Days With A Threat For Heavy To Excessive Rainfall In Places During The Remainder Of This Week Into Next Week
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 new surge of tropical moisture from the Gulf of Mexico will combine with an approaching cold front to increase chances for heavy-excessive rainfall, especially from the Cumberland Mountains westward and northward into next week amid a persistent, slow to change weather pattern.
*NOTE – The position of an approaching cold front into next week will determine where the corridor of heaviest rains set up across the region. Different models, and individual ensemble members of the global models, are currently varied on where this will be. Stay tuned for updates.
Overnight Into Wednesday Morning
Humid with areas of dense fog. Small chance of a shower. SSE-SSW winds 5-15 mph, with higher gusts, along middle to upper elevation mountain ridges. Temperatures in the 60s to around 70 degrees.
Wednesday Afternoon
Partly cloudy. Humid. Chance of hit-miss showers and tropical downpours in thunderstorms. Winds SE-S at 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 ).
Wednesday Night Into Thursday Morning
Humid & hazy. Areas of dense fog. Chance of hit-miss showers & tropical downpours ( especially in the evening ). Winds S-SW at 5-15 mph, with higher gusts, on mid-upper elevation mountain ridges. Temperatures varying from the 60s to around 70 degrees.
Thursday Afternoon
Humid & hazy. Hit-miss showers & tropical downpours in thunderstorms. Light & variable winds. Temperatures in the 70s to lower 80s ( hotter south toward the Tri-Cities ).
Thursday Night Into Friday Morning
Humid & hazy. Areas of dense fog. Chance of hit-miss showers & tropical downpours ( especially in the evening ). Winds S-SW at 5-15 mph, with higher gusts, on mid-upper elevation mountain ridges. Temperatures varying in the 60s to around 70 degrees.
Friday Afternoon
Humid & hazy. Hit-miss showers & tropical downpours in thunderstorms. Light & variable winds. Temperatures in the 70s to low-mid 80s ( hotter south into the Tri-Cities ).
Weather Discussion ( Persistence )
Although a break from downpours and hit-miss storms was enjoyed by most on Tuesday, beneath tropical skies, the wet pattern of Summer 2016 shows no signs of letting up with renewed moisture streaming into the Cumberlands during coming days into this weekend-next week.
Break For Most On Tuesday – August 9, 2016
A recap of wetness since July 1 finds more than a foot of rain falling in the City of Norton during the 40 day period, with 10.56″ measured prior to that in May & June. This as downtown businesses clean up from Monday’s flash flood.
A total of 26 of the past 40 days ( 65% ) have
featured measurable rain in the City of Norton.
Summer 2016 Rainfall Total: 17.14″
( 22.64″ of rain since May 1 )
2016 Precip Total: 38.42″
*2016 precipitation totals have topped 45.00″ in wetter portions of the High Knob Massif ( about average for the City of Norton and the High Knob Massif for this point in a year ).
High Knob Massif Webcam – University Of Virginia’s College At Wise
*When SE winds blow skies are often gorgeous in the High Knob Massif area with many wave clouds and other orographic forms.
Tuesday temperatures reached low-mid 80s from Norton-Wise into Clintwood, with 70s amid upper elevations above 3000-3300 feet in the High Knob Massif.
Nora 4 SSE – NWS Station In The Middle Elevations
An official MAX temp of 86 degrees was observed in Clintwood on Tuesday to mark the hottest day in August and the warmest since July 27. While the TRI is going for a Gold Metal in 90 degree days, the count remains at 1 for Wise, Clintwood, and 0 for Nora 4 SSE and the higher terrain above that elevation ( 2650 feet ).
*Just outside the Cumberland Mountains there have been 9 days at or above 90 degrees in Grundy ( Summer MAX 94 degrees ). That is not surprising given Grundy is around 1000 vertical feet lower in elevation than the City of Norton and 1350 feet lower than Wise.
*A steamy, muggy air mass with high dewpoints have made conditions at all elevations feel uncomfortable during this seemingly endless summer.
NAM 12 KM Model Total Rainfall Forecast To 8 AM Saturday – August 13, 2016
While models will continue to struggle to pinpoint where the heaviest rains will fall, a clear shift west has occurred this week with the 51-Member European Ensembles now showing the greatest rain potential from the Cumberland Mountains westward and northward over a prolonged time frame from late week into next week ( a clear persistence pattern signal with very slow changes over time ).
This makes sense given it fits the pattern of Summer 2016, where wettest conditions ( by far ) have occurred along and west to north of the Cumberland Mountain range versus the Tennessee Valley and most of the southern Appalachians.
*The SE flow pattern being less to much less productive than during summers when a wet feedback, instead of drought, is ongoing along eastern slopes of the southern Appalachians ( rains during August hopefully helping to ease the drought in western North Carolina ).
USA Drought Monitor For August 2, 2016
The next drought monitor will be released August 11.
The spotty nature of summer rain in the Tennessee Valley is a major reason for so many 90 degree days from TRI to TYS-CHA ( i.e., Tri-Cities to Knoxville-Chattanooga ), as dryness breeds more dry times and increases heat.
*There was essentially no chance of reaching 90 degrees, officially, from Norton-Wise to Clintwood on Tuesday since a significant portion of insolation ( incoming solar radiation ) was being put into evaporation from vegetation ( transpiration ) and the ground. This was in contrast to the TRI area where much more insolation could be applied to heating up surfaces, that heated the overlying air, instead of running evapo-transpiration processes.
Here we are talking about official, radiation shielded thermometers that make measuring air temperatures in Wise, Clintwood, and the Tri-Cities equivalent to each other. Not to Weatherbug sites, with roof sensors, or other such devices which tend to read in error during a pattern like this.
A forecaster in the Tri-Cities forecasts for the official MAX, and I do the same for Norton-Wise-Clintwood and our higher mountain terrain amid the Cumberland Mountains.
