Area Forecast Discussion
Issued by NWS Blacksburg, VA
Issued by NWS Blacksburg, VA
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252 FXUS61 KRNK 061452 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 1052 AM EDT Sat Jul 6 2024 .SYNOPSIS... Another very warm day is in store, but humidity will be less for most compared to Friday. A front lingers across the Piedmont. The front vacillates over the area into Monday, and we will see a chance for thunderstorms each day. && .NEAR TERM /THROUGH SUNDAY/... As of 1035 AM EDT Saturday... Key Messages: 1. Heat Advisory remains for parts of the NC and VA Piedmont and Southside VA. Some records may be reached or broken, see Climate section below. 2. Less chances for storms today as drier air nudges southeast limiting chance to over southern VA into NC. Moisture has come down compared to last night as evidence by 12z RNK sounding, where pwats fell from 1.71 inches Friday evening to 1.19 inches this morning. However, pwats remain elevated close to 2 inches at GSO this morning. There is a sharp gradient between higher moisture and lower dewpoints. Numerous models trend slightly drier today and push the chance of storms further southeast across NC into eastern VA but enough moisture convergence along a front in the higher theta-e gradient will lead to scattered storms roughly from the NC mountains to southside VA, but again, trends are further southeast so don`t be surprised if the majority of our forecast area stays dry this afternoon. With the lower dewpoints, heat indices may not reach advisory levels, but at this point still hot with highs in the mid to upper 90s in the piedmont, so not making any changes to the headlines. Previous discussion... A few showers/isolated thunderstorms were moving across our VA/NC Piedmont along a surface trough, and were remnants of a complex of storms from last night. A cold front was just to our northwest, and will move into our VA Counties around 8 AM. We may see a few showers, but most of the activity will wait until the front reaches a Boone, NC, to Martinsville, VA, to Red House, VA line where much juicier air will be. Short wave energy arrives in SW flow later in the afternoon and evening and will impinge on this region. PWATs over the Piedmont where storms are likely will be at least 2.10", while drier air will already be filtering into the mountains north of the front. Last night, GSP`s soundings had 2.22" PWAT, which is extremely high and above climatology. With the front mostly through our forecast area, and instability pooled mostly to our southeast, expect the main concern to be heavy rain leading to flooding along and south of the Boone to Farmville line mentioned earlier. We already saw some instances of the last night, and with such high moisture content, slow storm motion, and recent rains to boot, it will not take much to have problems. This is supported by WPC`s Slight Risk for Excessive Rain area. Compressional warming along the front as well as high dew points and continued warmer than normal temperatures (850mb temperatures around 20C) has lead to the need for another Heat Advisory for Buckingham, Appomattox, Campbell, Halifax, Pittsylvania, and Caswell Counties from 11 AM to 8 PM today. Tonight, cooler and drier air continues to filter in, but showers may continue over NC depending on where the front stalls. Where skies clear, expect dense fog, especially in the valleys and where it rains. Confidence in the near term is moderate due to uncertainty in frontal location. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 400 AM EDT Saturday... Key Messages: 1: Boundary keeps showers largely south of Highway 460 until Monday A stalled boundary will sit around the VA/NC border on Sunday, with drier air to the north and much moister air to the south of it. The drier air will limit the formation of showers and storms in VA, while the front will encourage them around the border and to the south of it. By Monday the front will start to wash out, allowing more moisture to slowly creep northwards. As a result, showers and storms will also spread north and impact the entire CWA on Monday afternoon. Temperatures will be slightly above normal during this time period, with highs in the 80s to low 90s. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 420 AM EDT Saturday... Key Messages: 1: Unsettled with storms through most of the week Next week will be a fairly standard mid-July week, weatherwise. Another front will slide into the Mid-Atlantic by late Tuesday, and stall out. This will lead to scattered showers and storms to form each afternoon and evening along with diurnal heating. Generous PWATs could lead to some heavy showers, and therefore some localized flooding concerns. It will come down to what areas receive showers multiple days in a row. Steering flow is week, so storms will not be very progressive in nature, potentially pouring onto one location for extended periods of time. Temperatures will regulate a bit more towards normal for this time of year, a welcome reprieve from the recent anomalous heat. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... As of 230 AM EDT Saturday... Areas of fog expected overnight with potential for IFR conditions in the mountains per visibility dropping below 3sm. A period of dense fog is likely in the mountain valleys and along the western slopes of the Appalachians where a layer of low level stratus may form. Any fog/stratus tonight is expected to dissipate by mid morning Saturday with return of widespread VFR Saturday afternoon. Average confidence in the above forecast. AVIATION OUTLOOK... Some lingering showers and sub-VFR possible Saturday evening in the DAN area. Fog possible through the period in the early mornings. The pattern stays unsettled such that daily chances for storms exists. Thinking mainly VFR but sub-VFR when it storms and any late night fog. Confidence is moderate for the extended aviation outlook. && .CLIMATE... As of 300 AM EDT Friday... Record highs for July 6th. Not expecting any but could be close at Lynchburg. Saturday 07/06/2024 Site Record High/Year Forecast Bluefield 92/2010 82 Danville 102 1990 95 Lynchburg 98 2010 96 Roanoke 100 1999 94 Blacksburg 94 2010 88 && .EQUIPMENT... KFCX radar is running in a degraded state. The radar receiver was damaged by heavy rain getting into the radome Friday afternoon. Please use surrounding radars or a radar mosaic until our equipment can be repaired. BLF ASOS...the tipping bucket failed Friday afternoon. Will await the morning Coop report from Bluefield and send a correction to Friday`s climate summary at that time. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...Heat Advisory until 8 PM EDT this evening for VAZ044>047-058- 059. NC...Heat Advisory until 8 PM EDT this evening for NCZ006. WV...None. && $$ SYNOPSIS...SH/WP NEAR TERM...SH/WP SHORT TERM...VFJ LONG TERM...VFJ AVIATION...SH CLIMATE...SH EQUIPMENT...PM