Williamstown, WV Weather

What Has Changed

No significant changes have been made to the ongoing forecast, and benign weather continues to be forecast well into next week.

Key Messages

1) Beyond the typical bouts of morning river valley fog, dry weather will dominate the forecast for the next 7 days, along with some patchy morning frost across the higher terrain.

Discussion

KEY MESSAGE 1...

In the mid/upper-levels, an Omega Block remains anchored across the Lower 48, with high pressure expected to continue dominating the forecast across the CWA for the next 7 days. The apex of the subtropical ridge, which is currently centered across the Great Plains, will gradually shift eastward over the next couple of days, as a high-amplitude, positively-tilted trough digs into the Desert Southwest. The superposition of the subtropical ridge relative to the CWA will maintain convergent flow aloft, keeping the formation of even diurnally-driven boundary-layer cu from occurring each afternoon. Excellent radiational cooling at night will result in the usual development of fog across the river valleys, with visibilities falling to one-quarter mile at times; and fog of any kind will erode by 14-15Z each morning through the weekend. Some slight reductions were made to the dewpoints for the forthcoming afternoons due to the full insolation, along with bias-corrected tuning of the overnight lows tonight and Friday night due to the arrival of a modifying mP airmass trailing the decayed front/surface trough that is expected propagate through the region later this afternoon and tonight. The arrival of this surface boundary should keep the development of frost during the nighttime hours in check; however, patchy frost cannot be ruled out across the higher terrain tonight and beyond.

Aviation

VFR conditions can be expected through the period with the exception of some late night early morning dense river valley fog. Fog will generally dissipate by 14Z.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...

FORECAST CONFIDENCE: High.

ALTERNATE SCENARIOS: Timing and location of fog could vary.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

UTC 1HRLY 19 20 21 22 23 00 01 02 03 04 05 06 EDT 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02 CRW CONSISTENCY H H H H M H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H L L PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H