... Upper disturbance exits tonight and Thursday. Gradual warming trend continues into early next week with isolated to scattered thunderstorms possible just about every afternoon.
NEAR TERM /THROUGH THURSDAY/... As of 235 PM Wednesday...
Mid/upper level low/vort max over the area easily visible as baroclinic leaf/S-curve on GOES-R imagery, even a well defined comma head most evident on vapor channels. Associated light rain showers were moving slowly north-northeastward through the Tug Fork area, with more stout convection beginning to fire in eastern KY, in breaks behind the leaf.
Afternoon heating is likely to expand convective coverage where sufficient heating occurs, mainly out ahead of the comma head, across east/northeast portions of the forecast area. However, breaks were developing with the leaf/comma head and, with the convection firing to the west, have allowed the chance for thunderstorms just about anywhere in the forecast area this afternoon and evening. With dew points in the lower to mid 60s, and the slow moving mid/upper level disturbance over the area, have again allowed thunderstorms to persist well into this evening, before slowly waning tonight.
Low shear and modest CAPE will lead to sub-severe thunderstorms with brief heavy downpours, and DAPE induced downbursts, but PW values only around an inch and a third or less should keep rainfall amounts manageable/localized.1
The valley fog forecast tonight is a persistence forecast, given similar dew points, and fog formation early this morning even where it had not rained last night. However, altocumulus associated with the upper level disturbance lowers confidence in the dense fog forecast.
The mid/upper disturbance continues to move slowly east on Thursday, still close enough for the chance for afternoon thunderstorms in and near the mountains. Convective parameters remain similar to today with PW values just over an inch and light flow/shear, and a mid level cap begins to develop. Nothing more than brief downpours/gusts should result.
Used the MET for cooler valleys early Thursday morning, otherwise central guidance temperatures and dew points reasonable.
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... As of 235 PM Wednesday...
High pressure ridge builds in for the rest of Thursday with maybe a few lingering showers leftover from an upper level wave that should be kicked out to the northeast by Thursday night. These potential showers should only be confined to the northeast mountainous area. High pressure dominates Friday with little in the way of any chances for a diurnal pop-up shower with drier air filtering in. An elongated trough moves in from the west by the late morning on Saturday enhancing chances of showers/storm over our western periphery of the CWA. As the trough moves overhead through the day chances will spread throughout the entire CWA, especially by the late afternoon when daytime heating kicks in.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... As of 235 PM Wednesday...
The aforementioned feature should flatten out by the late evening on Saturday therefore decreasing any chances for showers into the overnight as high pressure builds in from the west. High pressure will influence Sunday into Monday with little in the way of precipitation as a lack in moisture will be apparent. A warming trend will commence with temperatures increasing to the low 90's, anomalously higher than the climatological norm. By late Monday, a low pressure system forecast to travel east across the northern side of the Great Lakes will influence the area by creating the possibility for showers/storms as the feature drops a frontal boundary across our area. Being so far out, was surprised long range models still had a good handle on timing and location, therefore accepted blended model guidance which equated to chance showers and storms for Tuesday and Wednesday. Temperatures will continue to hover above average for this time of year past the long term. Hopefully this aforementioned system will deliver the needed precipitation to prevent any further drought conditons across certain locations of the area who are in drought condition zero.