The Storm Prediction Center has issued a Marginal Risk for Severe Thunderstorm development during Tuesday Into Wednesday AM ( August 1 )
Storm Prediction Center Risk Regions
*Showers and downpours in thunderstorms will become likely into mid-late week. Heavy to locally excessive rainfall amounts will need to be closely monitored across the southern Appalachians.
Previous Headlines
*A drier and less humid air mass Saturday into early Sunday will give way to increasing moisture levels once again late Sunday into Monday ( July 30 ).
This will allow for cool nights, especially at upper elevations both Saturday and Sunday mornings, with a nice Saturday expected.
*Showers & downpours in thunderstorms will become likely next week with a locally heavy to excessive rain potential over the southern Appalachians and southeast USA.
Overnight Into Saturday Morning
Becoming clear. Cooler. Areas of dense fog, especially at middle to lower elevations. Winds NW-N 5-10 mph with higher gusts on mid-upper elevation mountain ridges into the overnight, then becoming light by morning. Temps from low-mid 50s at upper elevations to the upper 50s to around 60 degrees ( 40s possible in colder valleys at the upper elevations ).
Saturday Afternoon
Partly cloudy. Pleasant. Winds NW-NNE at generally less than 10 mph. Temperatures varying from 60s to lower 70s at upper elevations to 75-80 degrees.
Saturday Night Into Sunday Morning
Mostly clear ( some mid-high clouds ). Areas of dense fog in stream-river valleys ( especially at lower elevations ). Light easterly winds. Temperatures varying from 40s to low 50s in cooler valleys at upper elevations to the lower 60s.
Sunday Afternoon
Partly cloudy. Increasing haze and humidity with a chance of a hit or miss shower or thunderstorm. Light SE-S winds. Temperatures varying from low-middle 70s to the lower 80s ( coolest at upper elevations ).
Sunday Night Into Monday Morning
Becoming cloudy with a chance of showers & thunderstorms overnight into morning. Winds SE-S 5-10 mph, with higher gusts, on mountain ridges-exposed plateaus below 2700 ft. Winds S to SW 8-16 mph, with higher gusts, on mountain ridges above 2700 feet. Temperatures widespread in the 60s to around 70 degrees in warmer locations.
Monday Morning Through The Afternoon
Partly to mostly cloudy with a chance of showers and thunderstorms. Local downpours. Some storms could be strong to locally severe. Winds light SSE-SSW outside of thunderstorms. Temperatures varying from the lower 70s to the lower 80s.
Monday Night Into Tuesday Morning
A chance of showers & thunderstorms. Local downpours. Winds SSE-S at 5-15 mph on mountain ridges and plateaus below 2700 feet. Winds S-SW at 10-20 mph, with higher gusts, on mountain ridges above 2700 feet. Temperatures widespread in the 60s. Areas of fog.
Tuesday Through Thursday
Periods of showers & thunderstorms. Locally heavy rain. Afternoon temperatures in the 60s to middle 70s will be common, especially in locations along and north of the High Knob Massif and Tennessee Valley Divide.
Weather Discussion ( Brief Break )
Early Monday ( July 30 ) Update
Increasing moisture levels will fuel intervals of showers and thunderstorms through the coming week. While some storms could become strong to locally severe, the greatest areal threat will be heavy to locally excessive rain amounts.
European Model 500 MB Height Anomalies: Days 1-5
A rather classic heavy rain setting for this time of year is being forecast by the European Model and its 51-Member Ensemble Mean, with general 1.50″ to 3.50″ basin average rainfall amounts during the work week ( implying much heavier local amounts will be possible ).
Previous Discussion
A brief break from the stormy, wet pattern for most of this weekend should be enjoyed before moisture increases again by the beginning of the work week.
High Knob Massif Webcam – University Of Virginia’s College At Wise
A wet Friday afternoon found 1.00″ to 2.00″ of rain falling in the Norton-Wise-Coeburn area, especially over the City of Norton into Coeburn and adjacent northern slopes of the High Knob Massif.
Little to no rain fell to the south at Big Cherry Dam where around 7.00″ of July rain have been measured, illustrating the local nature of heavy Friday afternoon downpours ( more than 4.00″ of rain fell at Big Cherry Dam in the past week to generate overflow ).
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 3-7
Another deepening upper air trough will set the stage for more heavy to locally excessive rainfall during the last days of July into early August.
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 6-10
While details remain to be worked out, the European Model ensemble mean is forecasting heaviest rains to fall over the southern Appalachians and along the Coastal Plain as deep tropical flow develops around strengthening Bermuda High pressure in the western Atlantic Ocean.
