Area Forecast Discussion
Issued by NWS Blacksburg, VA
Issued by NWS Blacksburg, VA
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333 FXUS61 KRNK 161742 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 142 PM EDT Mon Sep 16 2024 .SYNOPSIS... Potential Tropical Cyclone Eight moves onshore this afternoon and drifts through the Carolinas through Wednesday bringing a prolonged period of rain to the area. A low probability of rain remains in the forecast through the end of the week as high pressure wedges down the Appalachians. && .NEAR TERM /THROUGH TONIGHT/... As of 120 PM EDT Monday... Key message: - Rain spreading in this afternoon and evening becoming moderate to heavy at times along/east of the Blue Ridge into Tuesday - Northeast-east winds increasing with gusts to 20-35 mph Low still centered off the SC coast this afternoon expected to move inland by late afternoon between CHS-ILM. Rain already reaching the NC mountains but drier air north has kept it limited. Leaning toward 12z 3km NAM as it had the setup with the rain and storm better. Better lift arrives by mid- late afternoon and moreso tonight into Tuesday as the low moves inland to upstate SC by Tuesday morning, weakening considerably by Tuesday afternoon. Stronger winds stay below advisory levels but upped gusts a little especially over our NC and southern VA counties. Some gusts over 30 mph may lead to weaker trees or limbs to fall. Rainfall of 1-3+" over a 24-36 hr period should limit flooding concerns given how dry we have been, so no flood watches at this time. Rises mainly expect along the upper New River and lower Roanoke/Dan basin from this event but staying well below flood stage given low flows. PWATS off our 12z RNK sounding hanging around 2/3" but should jump to over an inch by this evening and over 1.5"-2.0" tonight. Several bands of heavier rain and enhancement along the Blue Ridge takes shape overnight into Tuesday but models keep the rain/showers moving along which unless there is training should limit amounts for most. As far as instability that also looks fairly limited but could see a few lightning strikes over southern VA into the NC piedmont Tuesday. Temperatures run above normal tonight with mid to upper 50s in the mountains to mid 60s piedmont. Clouds/showers will keep temperatures below normal Tuesday with 60s in the mountains and lower 70s east. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... As of 1245 PM EDT Monday... Key Messages: 1. Rain chances continue through the midweek. 2. Highest chances for rain Tuesday night through Wednesday. 3. Near to below normal temperatures. The remnants of Potential Tropical Cyclone 8 will slowly move into the Carolinas through Tuesday, bringing rounds of moderate to heavy rainfall to the area. Models have generally shifted the track of the system farther southwestward, but some uncertainty exists after Wednesday where the remnants of this system may go, with no strong feature aloft to steer it in any specific direction. That being said, forecast confidence after Wednesday decreases, but overall, chances of rain continue through the midweek, possibly into the end of the week, as the remnants of PTC 8 meander near the Carolinas and Tennessee Valley. The majority of the rain will fall Tuesday, but continue into Wednesday. Repeated rounds of rainfall will increase the risk of flooding, but dry antecedent conditions will help to limit flooding potential. The track of this system will influence rainfall amounts through the period, but highest amounts still look to be along the Blue Ridge, particularly over the southern parts of the mountains, in northwest NC and southwest VA. Some instability and bulk shear around 30 knots associated with the system as it pivots into and through the Carolinas could lead to a few thunderstorms Wednesday and Thursday afternoon, though confidence is low. With cloud cover and chances for rain through the period, expecting temperatures to be near to below normal. && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 100 PM EDT Monday... Key Messages: 1. Chances for rain continue into the weekend, but gradually decrease. 2. Near to below normal temperatures through the period. With the remnants of Potential Tropical Cyclone 8 still in the vicinity, rainfall chances continue into the end of the work week, mainly for central and eastern VA and NC. However, an upper ridge building over the central US will start to push the upper trough/low associated with the remnants of the system out towards the Atlantic. Surface high pressure moves into the northeast US again by the second half of the week, and start to wedge along the eastern side of the Appalachians. With the wedge in place, any rain would have to overcome the dry air, and so will help to lower rain chances through the weekend. That all being said, look for increasing periods of sunshine after Friday through the weekend. Temperatures will be near to below normal for this time of year through the forecast period. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... As of 120 PM EDT Monday... Aviation conditions not too bad this afternoon but looking at MVFR to IFR by this evening at all taf sites with rain moderate to heavy at times impacting DAN/ROA/BCB and perhaps LYH. Vsbys should drop to 2-5 miles in the rain. Cigs by Tuesday morning stay at or below 1kft for most of the area with showers off and on. Generally east to northeast winds through the period. Gusts between 15 to 30 knots are possible for KDAN and KLYH, and 20 to 35 kts the along the Blue Ridge. Forecast confidence is above average for ceiling, visibility, and wind with rain tonight. EXTENDED AVIATION OUTLOOK... Periods of sub VFR conditions are possible through Thursday, as a low pressure system brings rain and clouds to the area through the midweek. Widespread rain continues into Tuesday. We may finally see less coverage of showers by Friday into Saturday. && .EQUIPMENT... As of 135 PM EDT Monday... The Lynchburg ASOS (LYH) is still experiencing data transmission issues, mainly at night due to FAA outage. Please use caution when using data from this site, as some may be missing. No estimated date for return to full service at this time. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS/WP NEAR TERM...WP SHORT TERM...AS LONG TERM...AS AVIATION...AMS/WP EQUIPMENT...AS/WP