The main concern for the mountains is how far inland will the remnants of Florence get + how fast will they move. The National Hurricane Center has been going with the European Model which has been, by far, the most consistent with the track.
Main jet stream cores are far to the north, and while there is some SW flow over the area now that is likely to weaken with large-scale subsidence in advance of Florence by later this week.
GOES-16 Water Vapor Image – Evening of September 10, 2018
While I think it will be Wednesday into Thursday before confidence on the inland track and speed increases by a significant amount, it is possible to discuss some of the possibilities ( for planning ).
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 1-5
The 51-Member European Ensemble Mean ( above ) shows Florence moving beneath a 500 MB upper air ridge axis during the next 5 days, which has been responsible for recent intensification.
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 4-8
The 4-8 day period, during September 14-18 above, keeps the main jet stream cores far to the north and a large, elongated upper ridge over the eastern USA.
The break or weakness in the ridge ( above ) shows where the remnants of Florence are likely to be.
Worst And Best Case Scenarios For The Cumberland Mountain Range
It appears nearly certain that Florence will turn into a disaster, perhaps a Mega-Disaster, for portions of the middle Atlantic. Historical odds would favor locations along and east of the Blue Ridge for worst conditions.
With the above noted, at this point in time, major flooding can not yet be ruled out for the Cumberland Mountains and surrounding Mountain Empire.
*While the European Model has been most consistent, individual runs and ensemble members have been widely varied on MAX rainfall amounts with up to 48.00″ ( 4 Feet ) in the worst case scenario being predicted for portions of Virginia and North Carolina along and east of the Blue Ridge. Anything remotely close to that would generate historic, deadly flooding ( of course, anyone knows that ).
Individual runs of the operational European, as well as its ensemble members, can be expected to continue to vary on rainfall amounts during the next couple of days despite a rather consistent trend of bringing a major hurricane into the Atlantic coast. A problem is with weak winds aloft the remnants will begin to slow down once it loses forward momentum and begins to feel frictional drag of the land.
Here I will briefly outline what would be the best and worst case scenarios for the Cumberland Mountains, where this website is mainly focused upon.
Best Case Scenario
The best case scenario to watch for would be that the remnants turn north following landfall and remain far to the east, keeping the Cumberland Mountains and Mountain Empire amid the subsidence zone of sinking air around the periphery of the core.
With a system like this one must begin to talk about orographic forcing, such that the best case setting for the Cumberland Mountains with the remnants moving far inland would be for them to move toward northern Georgia, southwestern North Carolina to maintain a southeasterly flow into southwestern Virginia and eastern Tennessee. This scenario, of course, would be the worst case for western North Carolina.
Worst Case Scenario
The worst case scenario to watch for would be for the remnant core to move toward northern North Carolina and southwestern Virginia, east of the Cumberlands, with a wrap-around northerly upslope flow generated into the local mountans with a stalling system. The orographics would then favor excessive rainfall over the local mountains and near the core of the remnant low ( especially on enhanced nocturnal convergence ).
There are many other possible scenarios, of course, but these are just ones mainly focused upon the Cumberland Mountains ( and based upon past climatology ).
*Above average temperatures will tend to dominate much of this work week within a hazy, maritime tropical ( mT ) air mass. Showers & thunderstorms, with hit-miss downpours, will be possible ( especially mid-morning to early evening ).
Due to weak winds aloft any shower or thunderstorm will be slow moving and capable of dropping heavy rainfall over local areas.
*The coverage of showers & thunderstorms will increase later this weekend into the Labor Day Holiday period, with downpours. Temperatures will tend to slightly decline due to an increase in cloudiness and showers-thunderstorms.
*An above average temperature trend is currently expected to continue through the first week of September.
Overnight Into Monday Morning
Partly cloudy to mostly clear. Areas of fog. Light S-SW winds generally less than 10 mph on mid-upper elevation mountain ridges. Temperatures varying from mid-upper 50s in valleys at upper elevations to the low-middle 60s.
Monday Morning Through The Afternoon
Partly cloudy. Chance of hit-miss showers-thunderstorms. A local downpour possible. Light & variable winds. Temps varying from low-mid 70s to the low-mid 80s ( coolest at upper elevations above 3000 feet ).
Monday Night Into Tuesday Morning
Partly to mostly clear. Small chance of a shower or storm. Light and variable winds becoming SSW-WSW at 5-10 mph, with higher gusts, mid-upper elevation mountain ridges. Areas of fog. Temperatures varying from upper 50s to lower 60s in cooler valleys to middle-upper 60s.
Tuesday Morning Through The Afternoon
Partly cloudy. Chance of hit-miss showers-thunderstorms. Local downpours possible. Winds S-SW generally less than 10 mph outside any storms. Temperatures varying from the lower-middle 70s to the lower-middle 80s.
Tuesday Night Into Wednesday Morning
Partly to mostly clear. Small chance of a shower or storm. Light and variable winds becoming S-SW at 5-10 mph, with higher gusts, mid-upper elevation mountain ridges. Areas of fog. Temperatures varying from mid-upper 50s to lower 60s in cooler valleys to the middle-upper 60s.
Wednesday Morning Through The Afternoon
Partly cloudy. A chance of hit-miss, slow moving showers and thunderstorms. Downpours likely in any activity. Light SSW-SW winds generally less than 10 mph. Temperatures varying from low 70s to the lower 80s ( warmer south into river valleys of the Clinch, Powell, and Holston ).
Wednesday Night Into Thursday Morning
Variable clouds. Chance of a shower or thunderstorms. Downpours possible. Areas of fog. Winds SW-W at 5-10 mph, with some higher gusts, on mid-upper elevation mountain ridges. Temperatures mainly in the 60s.
Weather Discussion ( More Summer )
A late summer weather pattern will return to dominate conditions through the Labor Day Holiday. This comes in wake of pleasant conditions in recent days.
High Knob Massif Webcam – University Of Virginia’s College At Wise
Minimum temperatures fell into the 40s in cooler mountain valleys at upper elevations during August 23-25 ( low-mid 40s in coldest locations ).
High Knob Massif Mesonet *Big Cherry Lake Valley 2 June 1-August 25, 2018 Avg. Daily MAX: 70.9 degrees Avg. Daily MIN: 57.6 degrees Summer MEAN: 64.2 degrees Highest Temperature: 79 Lowest Temperature: 46
*MAX temperatures were somewhat higher and MIN temperature were somewhat lower within open portions of the Big Cherry Wetland Valley. Temps are all National Weather Service calibrated and very accurate.
High Knob Massif Webcam-University Of Virginia’s College At Wise
A notable increase in haze, with some orographic clouds, was observed developing Sunday as a continental Polar air mass gave way to advection of maritime tropical air.
European 51-Member Ensemble Mean 850 MB Temp Anomalies: Days 1-5
Above average temperatures during the next 5 days, on average, will be supported aloft by mean upper air ridging across the southern and eastern USA.
European 51-Member Mean 500 MB Height Anomalies: Days 1-5
This basic pattern is expected to continue through the next 10 days, which includes the Labor Day Holiday period.
European 51-Member Mean 500 MB Height Anomalies: Days 6-10
*Showers & downpours in thunderstorms will continue at times, amid a humid air mass, into Tuesday Night.
Heavy to locally excessive rain amounts will remain possible in advance of a strong autumn-like cold front expected to arrive by late Tuesday.
NOAA’s Storm Prediction Center has issued a marginal risk of severe thunderstorm development along and in advance of this cold front.
*Cloud bases will lower and the air will turn notably cooler on northerly winds through Wednesday, with lingering showers possible in advance of a secondary dewpoint boundary that ushers in an early autumn-like air mass late Wednesday into Thursday.
An early autumn-like air mass will drop temperatures into the 40s to middle 50s within locations along & north of the High Knob Massif-Tennessee Valley Divide by Thursday AM. Even cooler air may be felt in colder mountain valleys by Friday morning ( August 24 ). Stay tuned for updates.
*The cooler, drier break will be temporary with a return of humid air and a trend toward above average temperatures by next weekend into the final days of August 2018.
Overnight Into Monday Morning
Partly-mostly cloudy. Muggy. Areas of dense fog. A chance of showers & thunderstorms. Locally downpours possible. Light SSE-SSW winds. Temperatures in the 60s to low 70s.
Monday Morning Through The Afternoon
Muggy & warm with a chance of showers & downpours in thunderstorms. Locally heavy rain possible. Light S-SW winds. Temperatures varying from upper 60s-low 70s in upper elevations to the upper 70s to lower 80s ( warmer south into the Great Valley ).
Monday Night Into Tuesday Morning
Mostly cloudy. Becoming breezy to windy. Chance of showers & thunderstorms. Local downpours possible. Winds S-SSW at 5-15 mph, with higher gusts, on mountain ridges-plateaus below 2700 feet. Winds SW 10-20 mph, with higher gusts, on mountain ridges above 2700 feet. Muggy with temperatures in the 60s to lower 70s.
Tuesday Morning Through The Afternoon
Showers & thunderstorms becoming likely. A few storms could be strong to severe. Local downpours. SW winds 5-15 mph, with higher gusts. Temperatures varying from upper 60s to the upper 70s.
Tuesday Evening Into Wednesday Morning
Showers & thunderstorms likely into the evening, then a chance of showers. A few storms could be strong-severe early with downpours. SW winds shifting W-WNW at 5-15 mph, with higher gusts into morning. Temps falling into the upper 50s to middle 60s.
Wednesday Morning Through The Afternoon
Mostly cloudy with a chance of showers. Low cloud bases at upper elevations, with dense fog into mid-morning to early afternoon at high elevations. Winds NW at 5-15 mph with some higher gusts. Temperatures varying from lower 60s to the low-mid 70s ( warmer south into the Great Valley ).
Wednesday Night Into Thursday Morning
Partly-mostly cloudy early, then decreasing clouds with areas of fog. NW-NE winds diminishing to 5-10 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures dropping into the 40s to middle 50s.
Thursday Afternoon
Sunny. Very pleasant. Blue skies. Light N-NE winds. Temperatures varying from lower-middle 60s in upper elevations to the lower 70s.
Thursday Night Into Friday Morning
Clear and unseasonably cool with a large vertical temp spread developing between the colder valleys and milder mountain ridges-exposed plateaus. Winds becoming SE to SSE at 5-10 mph, with higher gusts, on mid-upper elevation mountain ridges. Temperatures varying from upper 30s to lower 40s in colder valleys at upper elevations to the mid 40s to low-mid 50s ( mildest on middle elevation ridges ). Areas of dense river valley fog.
Weather Discussion ( Changes )
With the 12th Annual High Knob Naturalist Rally now just over 1 month away, it is time for a nip to be felt amid air of the high country. Yeah, to less humid air!
September 29, 2018 at High Knob Lake Recreation Area
Featuring the most mountain-top lakes of any mountain in the southern-central Appalachians, this year’s 12th Annual Naturalist Rally will be held at 3500+ feet above mean sea level where the air is always cooler in the high country.
USDA Forest Service – High Knob Lake Recreation Area – Summer 2018
Meanwhile, the relentless stretch of muggy air continues for a little while longer until the first autumn-like cold front ushers in a temporary break by mid-late week.
High Knob Massif Webcam – University Of Virginia’s College At Wise
A refreshing and much cooler air mass will temporarily bring a dramatic change to the mountain area during the August 22-23 period into Friday AM of August 24.
European Model 850 MB Temp Forecast At 8 AM August 23, 2018
The middle range trend will be for humid air and above average temperatures to return during the final days of August 2018.
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 6-10
NOTE: The 5.24″ of rain measured in Clintwood during August 1-19 pushed the annual total to 46.03″ ( 14.45″ above the 1981 to 2010 average for this point in a year ). The January 1-August 19 total being near the long-term annual average for Clintwood.
NWS Precipitation Analysis – Percent of Normal – During Past 90-Days
*Although a general 47.00″ to 57.00″ of precipitation have fallen in the City of Norton-High Knob Massif area so far this year, the actual annual departure is generally only near to a little above average. This is due to hit-miss summer thunderstorms and local wet feedbacks, superimposed upon the larger-scale weather pattern, which have allowed certain sites and corridors ( e.g., northern Virginia into Pennsylvania ) to receive above to much above average summer rainfall across the eastern USA ( versus nearby locations with near average summer rains ).
ALERT For The Potential Of Localized Flash Flooding Into This Weekend With Slow Moving Thunderstorms
Torrential downpours in slow moving thunderstorms have dropped heavy rainfall amounts across Dickenson County & northern portions of Wise County as of 1:30 AM Saturday, with potential for additional development of this nocturnal activity. Folks living along streams and in low-lying, flood prone locations should remain alert through this weekend.
*A moist, humid air mass will remain in place through this weekend with the potential for heavy to excessive rain amounts within localized places.
*The heavy rainfall threat is being enhanced by weak winds aloft beneath another anomalous, for this time of year, upper-level low with slow moving activity.
*A cold front will slowly work south and attempt to cross the mountains later in this weekend-early next week. The threat for heavy-excessive rain amounts will continue until somewhat cooler, drier air is transported south behind this boundary.
The Storm Prediction Center has expanded a marginal risk of severe thunderstorm development southwest to now include all of the mountain area through Wednesday
Storm Prediction Center Risk Regions
*A humid air mass will rule the mountain landscape through the upcoming week with chances of hit or miss showers & thunderstorms during early week.
*Another upper air trough will be developing over the eastern USA with increasing chances of showers and thunderstorms by later this week into the upcoming weekend ( August 8-12 period ).
*Near to above average temperatures during early-mid week will tend to cool with increasing showers and thunderstorms by later in the week-weekend.
Overnight Into Monday Morning
Partly-mostly cloudy. Chance of a localized shower. Areas of valley fog. SW winds 5-10 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures in the 60s to near 70 degrees.
Monday Morning Through The Afternoon
Mostly cloudy. Chance of showers & thunderstorms. Local downpours. Winds S-SW generally less than 10 mph outside of hit or miss showers-storms. Temperatures varying from lower-mid 70s to the upper 70s to lower 80s ( warmer south into the Great Valley ).
Monday Night Into Tuesday Morning
Partly to mostly cloudy. Chance of a shower or storm, especially during the evening. Areas of fog. Winds SSW-W at 5-15 mph with some higher gusts on mid-upper elevation mountain ridges. Temperatures widespread in the 60s.
Tuesday Afternoon
Partly to mostly cloudy with a chance of hit-miss showers and thunderstorms. Local downpours. Winds SW-W at 5-10 mph. Temperatures varying from the low-mid 70s in upper elevations to the low-mid 80s.
Tuesday Night Into Wednesday Morning
Partly to mostly cloudy. Areas of fog. Chance of a localized shower-thunderstorm. Winds SSW-WSW at 5-15 mph, with higher gusts, on middle-upper elevation mountain ridges. Temperatures from lower 60s to the lower 70s.
Wednesday Afternoon
Mostly cloudy. Periods of showers & thunderstorms. Local downpours. Some storms could be strong to locally severe. Winds SW-WNW at 5-15 mph, with higher gusts. Temps in the 60s ( upper elevations ) to the low-middle 70s.
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.
*Periods of showers and downpours in thunderstorms will continue through Tuesday into Wednesday before a brief decrease in activity, with lower rain chances, develops by Thursday ( July 26 ) as this current upper-level region of low pressure lifts out to the northeast.
Rain chances may remain seasonally low through much of next weekend before ramping back up, but this remains to be seen and will need to be updated as this time period gets closer.
*Another deepening upper-level trough is expected to begin development by next weekend through final days of July, with a heavy to excessive rainfall potential returning by the end of July into the beginning of August.
*This wetter and cooler than average pattern is expected to continue into the final month of Meteorological Summer.
Partly to mostly cloudy. Chance of a shower. Dense fog at highest elevations. Areas of valley fog at lower elevations. Winds SE-S at 10 mph or less, except a few higher gusts on middle-upper elevation mountain ridges. Temperatures in the 50s to lower 60s.
Monday Morning Through The Afternoon
Partly-mostly cloudy. A chance of showers & thunderstorms with hit-miss downpours. Light SSE-S winds. Temperatures varying from the upper 60s to lower 70s to the upper 70s to lower 80s ( coolest at upper elevations ).
Monday Night Into Tuesday Morning
Partly-mostly cloudy. Chance of a shower or storm. SE-S winds at 5-10 mph, with higher gusts, mid-upper elevation mountain ridges. Temperatures varying from the upper 50s to the middle 60s. Areas of fog.
Tuesday Morning Through The Afternoon
Showers & thunderstorms likely. Local downpours. Light winds. Temperatures varying from 60s in upper elevations to the 70s at lower-middle elevations along and north of the High Knob Massif-Tennessee Valley Divide.
Tuesday Night Into Wednesday Morning
A chance of showers and thunderstorms. Downpours possible. Areas of dense fog. Winds shifting SW-W. Temperatures varying from the mid-upper 50s to the middle-upper 60s ( coolest in upper elevations ).
Wednesday Afternoon
Showers & thunderstorms likely. Local downpours. Winds NW to N at 5-10 mph, with higher gusts, on middle to upper elevation mountain ridges. Areas of fog, widespread at the highest elevations. Temperatures varying from 60s in the upper elevations to the 70s at low-middle elevations along and north of the High Knob Massif-TN Valley Divide.
Wednesday Night Into Thursday Morning
Showers & thunderstorms possible through the evening, with local downpours, followed by diminishing activity. Areas of dense fog. Winds WNW-NNW at 5-10 mph, with higher gusts along mid-upper elevation mountain ridges. Temperatures in the 50s to lower 60s.
**Given significant recent rainfall any heavy or slow moving activity could cause strong water level rises during coming days. Remain alert for changing conditions and to NOAA Weather Radio and your favorite media sources for any alerts or warnings which may be needed.
Weather Discussion ( Wet Pattern )
Tuesday Afternoon Update
High Knob Massif Webcam – University of Virginia’s College At Wise
Hit-miss afternoon downpours and cool summer air were featured Tuesday, especially within upper elevations in the High Knob Massif where the daytime max held in the 60s. This contrasted with an afternoon high of 78 degrees in Clintwood where conditions had finally remained dry.
*Temperatures dropped into the upper 50s to low 60s after 5:00 PM as rain fell on Eagle Knob and at High Knob Lake, and also cooled significantly where heaviest rains fell into parts of Powell Valley and the City of Norton into portions of northern Scott County.
European 51-Member Ensemble Mean 500 MB Height Anomalies: Day 4-8
Following a break Thursday ( with low rain chances ) the upper air pattern reloads with jet stream dynamics and a feed of tropical moisture setting the stage for more heavy to excessive rainfall during final days of July into early August ( the final month of Meteorological Summer ).
Previous Discussion
A wet and stormy weather pattern will continue to mostly dominate the mountain region through the remainder of July, with a few breaks ( low rain chances July 26 ) in the more organized activity.
Chimney Rock Gorge of High Knob Massif – July 20, 2018
A general 2.00″ to 4.00″ of rain fell across the mountain area during the July 20-22 period, from the high country of the High Knob Massif north to Breaks Interstate Park.
Totals between 3.00″ to 4.00″ fell on Big Cherry Lake basin and in Clintwood ( 3.26″ ), with 2.10″ measured at City of Norton WP. This boosted July rainfall tallies into the 6.00″ to 7.00″ range on Black Mountain and at Big Cherry Dam in the High Knob high country.
Turk’s-cap Lily ( Lilium superbum ) In High Knob High Country – July 14, 2018
Thursday ( July 26 ) is currently the pick day for lowest rain chances in the short-term as the current upper-level low dissipates and lifts out to the northeast.
This will be short-lived as additional upstream waves in the long-wave pattern begin to dive into the eastern USA and deepen ( i.e., develop ) a new trough. With luck the main impact of this will hold off until late in the upcoming weekend or early next week ( July 29-31 period ).
*While hit-miss showers & thunderstorms will be possible Friday, chances increase significantly tonight into early Saturday with the potential for strong to locally severe thunderstorms approaching from the WNW & NW-N.
Storm Prediction Center Day 1 Risk Regions
*A cluster of strong to severe thunderstorms will need to be closely monitored as it drops southeast to south out of the Ohio Valley Friday evening into the overnight of Saturday.
Storm Prediction Center Day 2 Risk Regions
*A cooler and occasionally wet weekend-early week period is expected as a upper-level low develops and moves south over the region by Sunday into Monday ( July 22-23 ). The coolest conditions will be over the high country where day time temperatures will mainly hover in the 60s ( only near 60 degrees at highest elevations ).
ECMWF Ensemble Mean 500 MB Height Anomalies: Days 1-5
Overnight Into Friday Morning
Partly-mostly cloudy. Small chance of a localized shower or thunderstorm. Areas of dense valley fog. Winds SSE to SSW at 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures varying from the upper 50s to the mid-upper 60s.
Friday Morning Through The Afternoon
Partly to mostly cloudy. Chance of hit-miss showers or thunderstorms with local downpours. SSE to SSW winds at 5-15 mph, with higher gusts. Temperatures varying from lower-middle 70s to the lower-mid 80s ( coolest in upper elevations above 3000 feet ).
Friday Night Into Saturday Morning
Showers & thunderstorms becoming likely. Some storms could be strong to severe. Locally heavy rainfall possible. Winds SSE-SSW at 5-15 mph, with higher gusts, on mid-elevation mountain ridges-exposed plateaus. Winds SSW-WSW at 10-20 mph, with higher gusts, on upper elevation mountain ridges. Temperatures widespread in the 60s.
Saturday Morning Through The Afternoon
Showers & thunderstorms. Locally heavy rainfall possible. Winds SSW to WSW at 5-15 mph, with higher gusts. Temps varying from the low-mid 60s at highest elevations to the mid-upper 70s.
*Downpours will remain possible through Tuesday as a cold front pushes across the mountains.
*Expect a refreshing air mass to arrive Tuesday night into Wednesday with gorgeous conditions for mid-summer by the afternoon into Wednesday night-Thursday morning.
*A cooler and stormy pattern develops by this weekend into early next week. A heavy to potentially excessive rainfall pattern is being monitored during the July 22-26 period.
Overnight Into Tuesday Morning
Hit-miss showers with a chance of thunderstorms. Winds WSW-WNW at 5-15 mph, with higher gusts, along middle to upper elevation mountain ridges. Areas of dense valley fog. Humid & hazy with temps in the 60s to around 70 degrees.
Tuesday Morning Through The Afternoon
Showers & thunderstorms likely. Local downpours. Some storms could be briefly strong to severe. Winds becoming NW at 5-15 mph, with higher gusts. Temperatures varying from around 70 degrees to the lower 80s ( coolest at highest elevations ).
Tuesday Night Into Wednesday Morning
A chance of evening showers or local storms. Becoming partly-mostly clear and less humid ( increasing high clouds by morning ). NW-NNE winds 5-10 mph, with higher gusts, along mid-upper elevation mountain ridges. Areas of dense fog developing. Temperatures varying from the low-middle 50s in cooler valleys at upper elevations to the low-mid 60s.
Wednesday Afternoon
Partly cloudy. Blue skies aloft. Pleasant. Less humid. Temperatures varying from the 60s to lower 70s at upper elevations to the upper 70s to lower 80s.
Wednesday Night Into Thursday Morning
Mostly clear and cool. Areas of dense valley fog. NE winds shifting E-SE on mid-upper elevation ridges. Temperatures varying from 40s in colder mountain valleys at the upper elevations to the 50s to around 60 degrees.
Weather Discussion ( Cooler Pattern )
The second half of Summer 2018 ( July 15-August 31 ) will be trending cooler than the first half of this season.
Gorgeous Afternoon at High Knob Lake on July 14, 2018
Although only 2 days have broken 80 degrees at High Knob Lake ( 81 degrees on July 4 being the max so far this year ), and no days have gotten out of the 70s on highest northern slopes in the massif, it has been a much different story for lowlands within the Great Valley where 19 days at or above 90 degrees have already been observed ( mostly in July ).
Daily Climate Date For The Tri-Cities ( July 1-15, 2018 )
Although much more pleasant conditions will be felt by Wednesday into Thursday, a moisture return will occur into this weekend and early next week to set the stage for cool, wet mid-summer conditions. This will be especially true if an upper-level low forms over the region as some recent model guidance suggests.
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 6-10
A upper trough over the eastern USA at this time of year can be a stormy setup, with relatively cold air aloft over top of low-level moisture. A heavy to potentially excessive rain pattern is being monitored heading into next week.
Stay tuned for later updates on a cooler, wetter pattern.
ALERT For The Potential Of Heavy-Excessive Rainfall Monday Along With A Chance Of A Few Strong-Locally Severe Thunderstorms
A high amount of atmospheric moisture is expected to support multiple waves of showers and downpours in thunderstorms through Monday. Locations with training storms, or prolonged heavy rainfall will be at risk for high water problems. Stay tuned to NOAA Weather Radio and your favorite media sources for possible watches and/or warning which may be needed.
Storm Prediction Center Risk Regions Through Monday ( June 25 )
The Storm Prediction Center has issued a Marginal Risk For Severe Thunderstorms Through Monday and during Wednesday ( June 25 and June 27 ).
Multiple rounds of thunderstorms are expected as a heat ridge builds into and across the region.
Storm Prediction Center Risk Regions For June 27
A heat ridge is predicted to build across the eastern USA during late week into the upcoming weekend and next week ( through the Independence Day Holiday ).
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 1-5
While the 51-Member European Model Ensemble Mean is predicting a classic eastern USA heat ridge to form, local heating will be largely dependent on the amount of clouds and thunderstorms which develops over the mountains during any given day.
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 6-10
The amount of soil moisture is important to how hot it can get at this time of year, with rainfall during the next few days combining with what has already been observed during June 2018.
NWS Precipitation Analysis and Doppler Estimated Month-to-Date Rainfall
