Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 260942 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 542 AM EDT Thu Apr 26 2018 .SYNOPSIS... An upper level trough will rotate east today and move across our region tonight into Friday. High pressure should arrive to provide drier conditions during the weekend. && .NEAR TERM /THROUGH TONIGHT/...
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As of 300 AM EDT Thursday... Upper low over the central Plains will dig southeast into northern Alabama by 18z this afternoon, then deamplifies tonight as it lifts eastward into southern portions of our forecast area. The surface low, closely attached to the upper low tracks northeast over the mountains and parallel to the Blue Ridge. Early this morning in the west, the upslope drizzle and light showers should end quickly. Expect some morning low clouds and fog until mid morning when they mix out with diurnal heating. Satellite images showed high clouds spreading northeast into our area ahead of a warm front and next area of low pressure. High and mid level clouds will continue to increased from the southwest as the next area of low pressure approaches. Kept similar timing of the showers generally after 18z as supported by this morning, HRRR, HiResW-Arw- east, NAM and GFS. High temperatures this afternoon will range from the mid 50s in the mountains to the lower 70s in the piedmont. As low pressure lifts northeast through area tonight, showers increase quickly. Decided to increase the mention of thunderstorms in the east with models showing a ribbon of cape around 500 j/kg, some better instability, and a period of enhanced UVM. Locally heavy rain is possible. The day one convective outlook indicated general thunderstorms across southeastern portion of forecast area. We will need to monitor for training of cells with heavier rains over the wet ground for any water problems. The threat for flooding appears too uncertain to entertain any Flood Watches at this time. Added some areas of fog tonight into Friday morning. Low temperatures tonight will vary from the mid 40s in the mountains to the mid 50s in the piedmont.
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&& .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... As of 500 AM EDT Thursday... The upper low that will bring another healthy round of rainfall to the region later today into Friday will be exiting fairly quickly toward the northern Mid-Atlantic by Friday afternoon. Broad troughing will continue across the eastern U.S. through the weekend. The northern stream will strengthen and deliver a good surge of cold air into the region for the weekend into Monday. Fortunately, this appears this will be the last surge of such strength as a notable pattern change is on track for next week. Temperatures through the weekend will average a bit below normal, especially high temperatures as 850mb temperatures bottom out around 0C north of the NC/VA border. Will need to watch for possible frost Sunday and Monday morning as a large Canadian surface high settles over the area. MOS guidance suggests lows in the mid 30s possible both Sunday and Monday morning. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... As of 520 AM EDT Thursday... Tranquil weather will cover most of this period as broad upper -level troughing across the eastern U.S. gives way to a high amplitude eastern U.S. ridge in response to a deepening western U.S. trough. The pattern will be very slowly progressive, leaving the eastern states blocked from the western trough moisture and effects until late in the week. 850mb temperatures will rise into +16C level by mid and late week allowing surface temperatures on the back side of a building Bermuda surface high to pump warm, increasingly moist Gulf air into the region. High temperatures by the end of the week will be above normal in the 70s west to the 80s east with lows only in the 40s and 50s. Freezing temperatures appear unlikely through the period with no threat of winter precipitation and very little if any threat for precipitation or thunderstorms. && .AVIATION /10Z THURSDAY THROUGH MONDAY/...
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As of 543 AM EDT Thursday... Northwest winds trying to hold MVFR clouds in the west this morning with the upslope flow. Pockets of low clouds and fog may created isolated IFR/LIFR conditions this morning. Surface obs indicated some dense fog to our west in West Virginia and Kentucky. Areas of fog should lift by mid morning with mixing and heating. In the east, VFR conditions will continue this morning. All sites will be VFR by late morning, but clouds will be increasing late in the period as the next system moves in our direction from the lower Mississippi valley. MVFR/IFR ceilings will spread east across the region after 00z Friday. Isolated showers will become more numerous tonight into Friday morning. An isolated thunderstorm is possible in the east this afternoon into tonight. However, they would be too isolated in nature to mention in tafs. Winds will generally remain light through the period. Medium confidence in ceilings, visibilities and winds during the period. Extended Aviation Discussion... MVFR/IFR ceilings along with rain showers will continue tonight and Friday. High pressure should build overhead to bring VFR conditions for all sites by Saturday afternoon. Good flying weather will persist through the remainder of this weekend and into Monday.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...KK NEAR TERM...KK SHORT TERM...RAB LONG TERM...RAB/RCS AVIATION...KK

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