Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 190609 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 209 AM EDT Wed Oct 19 2016 .SYNOPSIS... High pressure was off the southeast coast this afternoon. A cold front extended from Michigan to Missouri and will stall across the Mid Atlantic region on Wednesday. Low pressure will move along this boundary on Thursday, then push a strong cold front through the eastern United States on Thursday night and Friday. && .NEAR TERM /THROUGH TODAY/... As of 800 PM EDT Tuesday... Updated T/Td readings to better reflect current conditions. Added some cloud cover to match areas of patchy dense fog later tonight. Otherwise, no changes of significance needed at this time. As of 335 PM EDT Tuesday... High pressure was off the southeast coast this afternoon. Expect winds to diminish, especially in the valleys after sunset as a surface based inversion forms. Similar to past few nights, there will be a spread in temperatures between the cooler valleys and the higher elevations. Enough time with a clear sky and light/calm wind for fog development in the typical mountain and river valleys. As a front over the Great Lakes approaches from the northwest late tonight, mid and high clouds will increase over southeast West Virginia on Wednesday. This will hold back heating, but maximum temperatures will remain 10 to 20 degrees above normal. Records for Oct 19 may be found in the climate section of this forecast discussion. && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... As of 100 PM EDT Tuesday... The region will remain within the mild air regime Wednesday night into Thursday in advance of an approaching cold front. Temperatures will average fifteen to twenty degrees above normal. Low temperatures will range from the upper 50s to around 60 degrees across the region. Highs will again will range from the upper 70s to near 80 expected across the mountains with low to mid 80s across the Piedmont. Isolated to scattered showers, and a few thunderstorms, will be possible across the mountains by Thursday afternoon in advance of the cold front. Thursday night into Friday, the cold front is expected to move through the region along with its associated light to moderate showers. Isolated thunderstorms will be possible during the evening hours across western portions of the region. The operational models are now in fairly good agreement of precipitation associated with the front exiting the area by Friday afternoon. The closed low the GFS was promising is no more and is a more progressive wave like its national and foreign counterparts. However, so as not to not flip flop too much on our official forecast, we will continue to offer the potential for lingering showers in the east throughout the afternoon, just in less coverage than previously offered. In the western sections, we will continue to offer lingering upslope showers given the expected northwest 850 mb flow of at least 30 to 40 kts continuing into Friday night. Surface wind gusts across the mountains during this time period will commonly be between 25 and 35 mph with the higher peaks near 40 mph. Across the Piedmont, gusts of 20 to 25 mph will be more likely. Late Friday night into early Saturday morning, enough colder air is expected to move into the region to allow the s-word to be used in the forecast at elevations around or above 4000 feet agl. A brief period of snow or rain/snow mix will be possible during this time period at these elevations. Given how mild the conditions will have been leading up to this period, little or no accumulations are expected. Low temperatures Thursday night will be about five degrees cooler than Wednesday night. Highs on Friday will be lower in the wake of the front with readings back to values near normal for this time of year. && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 130 PM EDT Tuesday... During the Saturday through Monday this portion of the forecast the general synoptic pattern over the region will be one of a zonal to northwest flow aloft as an upper ridge builds over the Rockies and then translates eastward into the Mississippi River Valley. Closer to home, high pressure will again take up residency over the southeast United States. The impact of our area will be one of little or no precipitation and temperatures trending milder each day, with Saturday being the coolest day of the next seven days with readings at, or slightly below normal. By Monday, temperatures around five degrees above normal are forecast. What precipitation that does exist will be lingering, and dissipating, upslope showers across the western portion of the area that will conclude Saturday night. Monday night into Tuesday, a shortwave trough is expected to progress through the northwest flow and cross New England. An associated backdoor cold front is currently forecast to drop south into and through the area. While precipitation is not expected at this time, a drop to temperatures around normal for this time of year is anticipated. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... As of 200 AM EDT Wednesday... High pressure aloft will remain anchored over the southeast states through Wednesday. A cold front will approach from the north late Wednesday, but stall before moving into the area, then retreat to the north Wednesday night as a stronger cold front approaches from the west by Thursday evening. Generally VFR conditions will prevail through the TAF valid period. The only exception will be late night/early morning fog in the usual more sheltered/decoupled areas, including KLWB and KBCB. Confidence in fog this morning compared to the last several mornings is less given very warm temperatures yesterday, but given long nights and decoupling, feel that it remains a distinct possibility for IFR-LIFR vsbys/cigs in patchy dense fog mainly at KLWB and KBCB. Little to none expected at the remaining TAF sites, possibly MVFR at KLYH briefly. Low/Mid clouds will begin to increase from the west/northwest late Wed in association with the front to our north, but cigs are expected to remain VFR. No precipitation is expected within this time period...shower threat remaining confined to the Ohio Valley. Winds will be primarily out of the southwest, less than 5 kts before 14z, then increasing to 5-9kts after 14Z Wed, with a few gusts near 15kts possible during the peak heating part of the day. Medium to high confidence in cigs and vsbys through the TAF valid period. Medium to high confidence in wind speed/direction through the TAF valid period. Extended aviation discussion... A cold front is expected to move through the region Thursday night into early Friday. Expect the initial onset of scattered showers across the mountains late Thursday afternoon. A southwest to northwest wind shift is expected to occur Thursday night across the region with gusty winds behind the front continuing into Friday night and possibly Saturday. Areas of sub-VFR conditions will likely accompany the front and precipitation. A return to VFR conditions is expected for most areas Friday night into Saturday. The exception will be western parts of the region where a healthy northwest upslope flow, and lingering low level moisture, will prolong an IFR/MVFR ceiling during this time period. Even the mountain areas will become VFR again on Sunday. && .CLIMATE... As of 800 PM EDT Tuesday... No records max temperatures were set today, Tuesday, 18 October. Very warm temperatures are forecast again Wednesday. Currently, a record max temperature is forecast for Danville Wednesday and the record max temp is forecast to be tied in Blacksburg on Wednesday. Record maximum temperatures through Thursday, Oct 20. Oct 19 Location Record Max Bluefield.....81 in 1984 Danville......85 in 1953 Lynchburg.....88 in 1938 Roanoke.......91 in 1938 Blacksburg....80 in 1991 Oct 20 Location Record Max Bluefield.....79 in 1993 Danville......88 in 1984 Lynchburg.....85 in 1993 Roanoke.......84 in 2005 Blacksburg....82 in 1985 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AMS/RAB SHORT TERM...DS LONG TERM...DS AVIATION...PM CLIMATE...AMS is the U.S. government's official web portal to all federal, state and local government web resources and services.