Halloween Headlines

ALERT For Strong S-SW Winds Today Shifting W-NW_Much Colder Air With Plunging Late PM And Evening Temps

A strong pressure gradient developing along and in advance of a potent cold front will increase winds across the mountains, beginning at high elevations on Wednesday and mixing downward into middle-lower elevations on Halloween. In addition, there will be a marginal risk that some thunderstorms could become severe with damaging winds and hail. Orographic forcing will be activated with this system to also generate a heavy rainfall potential, especially within favored upslope locations along the High Knob Massif and Black Mountains.

ALERT For The Potential Of Strong-Severe Thunderstorm Development Ahead Of A Halloween Cold Front

*Strong winds will be driven by huge temperature anomalies between much above and below average conditions which develop pressure differences that form gradients to move air, as the atmosphere works vigorously to restore geostrophic equilibrium into Halloween.

*Orographic Forcing is a multi-parameter phenomenon of the Climate System whose foundation is based upon three-dimensional terrain interactions with wind speed and direction, as well as all associated aspects of advection and fluxes. It is a dual phase phenomenon featuring positive and negative (inverse) phases possessing both high predictability (in terms of weather) and long-term statistical influence (in terms of climate) on the natural world.

*Showers develop by mid-day Wednesday. Rain may be heavy at times during the afternoon, and increasingly wind driven at upper elevations where orographic pilatus clouds will develop to generate dense, ground-level fog.

*Wind driven rain, with a chance of thunderstorms, will develop Wednesday night into Thursday. Unseasonably warm conditions are expected in advance of a cold front. Locally heavy rainfall amounts are likely, with capping orographic feeder clouds at upper elevations to enhance the amount of rainfall reaching the surface in upslope locations (expect a prolonged period of dense, ground level fog, in orographic clouds, at upper elevations).

This will be the first system during Autumn 2019 to activate orographic forcing to any significant extent, with previous systems during September-October producing little variation in rainfall between the Tennessee Valley and mountains amid weak orographics. As is common during transitional seasons, mixed modes will remain possible with both convection and orographic forcing modes in operation which could act to skew precipitation amounts more than typically observed with only orographics and dynamical forcing.

*A significant fall of leaves are expected, especially at higher elevations where wind speeds will be strongest. Caution is advised on roadways across the area.

*A temperature crash will occur starting late Thursday afternoon into Friday morning, with widespread sub-freezing air temperatures and bitter wind chill factors. Rain could become mixed with sleet, snow, or freezing drizzle prior to ending, especially at higher elevations along the Cumberland-Allegheny Front and highest peaks of the Blue Ridge.

**A temperature drop of 35 to 45 degrees is expected between prefrontal warmth and invading cold by early Friday. Wind chills will drop into the 10s and 20s, except single digits to around 0 degrees on highest peaks by early Friday.

While 40+ degree temperature changes are common in mountain valleys between AM and PM readings, this will be the first system of Autumn 2019 to drive such a temperature drop across all locations within 12-18 hours, the first system to generate a widespread freeze, and the first system to drop wind chills on high peaks toward 0 degrees.

Colder November Weather Pattern

Temperatures will turn colder at the dawn of November and this will be a pattern that will dominate the first 1-2 weeks of the new month, at least in the mean, with a trend toward cold conditions across the eastern USA.

Persistent blocking supported by anomalously warm sea surface temperatures around Alaska will help to anchor a colder pattern downstream into the central-eastern portions of the USA.

Everything in the natural world can be modeled in wave form, including sea surface temp anomalies and all aspects related to the fluid atmosphere and climate system.

Wavelengths around the Northern Hemisphere, and planet, follow the physics law formulated by Wien, with longer wavelengths developing in colder air at this time of year replacing the shorter wavelengths of the summer season.

This pattern is currently predicted to strengthen during the 5-10 day period. Stay tuned for later updates.

ALERT For The First Widespread Frost And Freezing Conditions Of The Season During Sunday Morning And Monday Morning (October 13-14), Especially Away From Major Lakes And River Valleys.

A combination of very dry air advecting in from the Midwest, with clear skies and light winds, will set the stage for the first widespread frost and freezing conditions. Mountain valleys, especially at middle-upper elevations, will be most at risk for frost-freezing conditions into Sunday morning (13 October). Mountain ridges will generally remain frost-free, except for cold air drainage areas on plateaus.

All locations except for major lakes and river valleys, as well as exposed mountain ridges, will be at risk for frost and freezing conditions into Monday morning (14 October).

A hard freeze will occur within colder mountain valleys into Monday morning versus fog formation in the vicinity of major lakes and rivers which will offer protection from sub-freezing temps (frost could occur prior to river-lake fog formation).

Until the cold season deepens, a complex pattern of frost and freezing conditions will naturally exist within the complex, three-dimensional terrain setting of the Mountain Empire.

It is important for you to recognize your setting. If you live within a location that typically gets frost more than nearby places, then your risk will be higher during the next couple of mornings. If you live in a location that typically is the last to experience frost, then your risk of having frost will be low during this period.

Observed Conditions_13 October 2019

The City of Norton lies within a middle elevation valley, with a downtown benchmark elevation of 2141 feet above mean sea level. Norton receives cold air drainage from the high country of the High Knob Massif toward the southwest-south-southeast, and from Black Mountain toward the northwest and north, to generate often notable temp contrasts with exposed sections of the nearby Wise Plateau where air temperatures can be 10-20+ degrees milder on cold air drainage nights.

Air temperatures late Sunday evening were dropping quickly in mountain valleys, with 39 degrees in the City of Norton and 39.5 degrees in Clintwood (at 11:34 PM on 13 October). This is setting the stage for widespread mountain valley frost within locations along and north of the High Knob Massif, with fog in locations along and upstream of major lakes and rivers.

The first scattered frost and freeze of the season was observed within colder mountain valleys and plateaus early Sunday, 13 October, with temperatures in the 30s (34 degrees Norton and locally below freezing in high valleys of the High Knob Massif). Areas of fog were also common, especially at lower elevations.

Looking Ahead_First Rime?

Following early week warming, in wake of weekend and early Monday frost in colder valleys, the focus shifts to the next cold frontal boundary expected to spread light-moderate rain, with possible downpours, into the mountains during Wednesday (16 October).

Dropping temperatures and wind chills through the afternoon into Wednesday night and Thursday morning (17 October), with air temps falling through the 40s and 30s, will set the stage for the first rime formation of the season on highest peaks into early Thursday. That is the current trend to be followed through coming days, with even a high elevation snowflake or two being possible.

Forecast Verification_14 October 2019

Widespread frost and freezing temperatures were observed Monday morning, 14 October, with temperatures at or below freezing from the City of Norton to Clintwood.

A low of 32 degrees was recorded on the roof-top at Norton ES, with slightly colder temps reported by more standard sites near ground level in the Norton-Ramsey to Tacoma-Coeburn corridor, and the Big Laurel to Esserville valley corridor. An official low temperature of 31 degrees was recorded in Clintwood.

Fog was limited amid dry air, such that mountain valley frost was heavy and widespread in many valley locations upstream and downstream of the High Knob Massif in Wise County and parts of Dickenson, Lee and northern Scott counties, with the coldest temperatures within high valleys at upper elevations, above 2700 feet, in the massif where hard freezes occurred.

Fog formation was most widespread along the Clinch River, lower portions of the Russell and Levisa Forks of the Big Sandy River, and the Cumberland River in southeastern Kentucky.