Bryce Resort / Basye

Summary

SYNOPSIS

... A stalled frontal boundary will remain draped to the south of the forecast area throughout the weekend, bringing on and off showers and possible thunderstorms. A secondary cold front will move through the area on Monday before lifting as a warm front on Tuesday. This will bring a prolonged period of unsettled weather through next week.

NEAR TERM /THROUGH TONIGHT/... The cold air damming wedge signature is well in place per recent surface observations. The latest frontal analysis places this boundary down in central North Carolina arcing back into eastern Kentucky. Low-level easterly flow will ensure a cool damp day, accompanied by overcast skies, drizzle, and passing rain showers. Have opted to further lower today's high temperature forecast which keeps most spots in the mid/upper 50s. Perhaps a 60 degree reading or two are possible across central Virginia and far southern Maryland.

These cooler and more stable conditions combined with plenty of cloud cover will hinder thunderstorm development. Given this assessment, any threat for thunder appeared minimal enough to remove from the forecast today. WPC has the westernmost portions of the forecast area in a marginal risk for excessive rainfall. Isolated instances of flooding are possible, though dry antecedent conditions and 24-hour QPF values less than an inch will lead to most of the rainfall being beneficial.

Heading into the overnight hours, rain showers will persist and become more steady in nature. Moisture aloft will deepen overnight, leading to periods of heavier rain. Nighttime low temperatures will be in the upper 40s to 50s areawide.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... The aforementioned cold front stalled to our south, will lift through the forecast area on Sunday. This will bring noticeably warmer temperatures with highs in the 60s to low 70s throughout the area. Additionally, rain shower and thunderstorm chances will continue both Sunday and Monday. Thunderstorm chances will peak in the afternoon as instability increases with SPC having the forecast area in a general thunder risk each day.

High temperatures will continue to warm on Monday due to southerly flow ushering warm air. High temperatures will be in the 70s to low 80s areawide. Those at highest elevations will stay in the upper 60s throughout the day. Overnight low temperatures will stay in the upper 50s to low 60s each night.

LONG TERM /TUESDAY THROUGH FRIDAY/... Conditions will remain active through the long term period. A potent shortwave trough and associated area of low pressure will track across the Upper Midwest toward the western Great Lakes on Tuesday, and then across southern Ontario/Quebec on Wednesday. A surge of warm/moist advection will ensue at low levels in response on Tuesday as a warm front lifts northward through the area. Afternoon showers and thunderstorms appear likely on Tuesday in response to the combination of daytime heating and low level warm/moist advection on the synoptic scale. High temperatures on Tuesday should reach into the upper 70s and lower 80s.

Low-level forcing for ascent decreases somewhat on Wednesday as we move into the open warm sector and low-level flow turns westerly. Thunderstorms will be possible again Wednesday afternoon, but the coverage of storms should be considerably lower than Tuesday. In westerly low-level flow, a lee trough may serve as a potential focus for the development of storms. It will be noticeably warmer on Tuesday, with high temperatures expected to be in the mid-upper 80s.

A prominent shortwave will eject eastward from the Plains toward the Ohio Valley/Great Lakes on Thursday. An associated area of low pressure will track toward the northern Ohio Valley toward PA and NY by Thursday evening. This system will act to increase large scale forcing for ascent across the area, while also strengthening the wind field through the low-mid levels. As a result, showers and thunderstorms are expected again Thursday, some of which may be strong to severe in nature. High temperatures on Thursday are forecast to reach into the upper 70s to mid 80s.

Model solutions begin to diverge by Friday, with some models driving a cold front southeastward through the region Thursday night, while others hold off on the frontal passage until Friday night. As a result, a wide range of potential forecast outcomes exist. If we're post cold frontal on Friday, we'd have much cooler temperatures, and dry conditions. However, if the front remains upstream of the area, we'd have another day with warm and humid conditions, as well as additional chances for showers and thunderstorms.