Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 170538 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 138 AM EDT Tue Oct 17 2017 .SYNOPSIS... High pressure will build into the region overnight and remain across the area through Friday. && .NEAR TERM /THROUGH TODAY/... As of 900 PM EDT Monday... Observations show that current temps remain colder along the higher ridges than in the valleys as surface conditions remain mixed with the center of the high still to the northwest. Latest short term models indicate the best cold advection aloft including the lingering pressure gradient lasting until around midnight northwest before the high builds overhead late. This supports a quick drop in temps northwest valleys as things decouple, but still appears not enough coverage for a warning at this point espcly given fog potential in the deeper river valleys. Elsewhere looks like winds may stay up longer with mainly the valleys and eastern outlying areas along the Blue Ridge having the best shot at frost. Considered extending the advisory into Grayson cty along with the NC mountains but doubting enough frost coverage per breezes to warrant a headline at this point. Otherwise few changes with remaining cumulus fading to clear skies per dry air aloft off evening soundings, and chilly lows from 30s mountains to around 40 east as winds diminish. Previous discussion as of 315 PM EDT Monday... A cold front across the Southeast States will travel eastward into the Atlantic ocean this evening into tonight. High pressure will build in quickly this evening and will be centered over West Virginia by Tuesday morning. Winds will decouple in the western valleys overnight. Temperatures will drop enough for frost from the New River Valley into southeast West Virginia and the Alleghany Highlands. While there is some potential for isolated spots in the mountains to have lows around freezing, have held off on any freeze warnings due to lack of areal coverage and confidence in occurrence. Adjustments to the frost headlines can be made this evening depending on temperatures drops and winds tonight. Model guidance was actually warmer on low temperatures for tonight. In general, low temperatures will range from the lower 30s in the colder mountain valleys to around 40 degrees in the piedmont. Surface high pressure will remain in control of our weather Tuesday. Under bright sunshine, high temperatures will warm into the mid 50s in the mountains to the mid 60s in the Piedmont. && .SHORT TERM /TONIGHT THROUGH THURSDAY/... As of 315 PM EDT Monday... Quiet weather this period with gradual warming trend under high pressure. Should be a colder night Tuesday night in the piedmont as the high center shifts over central NC. Some frost headlines are possible again during this time, and will mentioned in the HWO. Lows will be in the 30s Tuesday night across the entire forecast area, with temperatures warming toward the mid to upper 60s Wednesday. As the high shifts a little to our east return flow is going to provide some increase in temps especially in the day. Lows Wednesday night will be in the mid 30s to lower 40s, where the warmer temps actually should be over the ridges in the west with mixing southeast flow. Temperatures warm above normal Thursday with highs in the lower to mid 70s. Another bubble high over the southern Appalachians Friday morning but with increasing heights and low level temps will experience temperatures a little milder with lower to mid 40s, except some upper 30s sheltered valleys. Expect little in the way of clouds this period. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 217 PM EDT Monday... Amplified upper ridge over the southeast will keep us on the warmer side of normal and dry heading into the weekend. By Saturday night, the ridge axis begins to get kicked east of our area by a deepening trough pushing into the middle of the country. Models are disagreeing on the depth of the trough with GFS weaker than the Euro, as it closes off a southern low over southern TX. The Euro on the other hand closes to low off further north closer to the northern TX. Since both show low closing off, and upper flow turning more southwest, influx of moisture should bring increasing chances of showers by early next week. Should be a dry weekend followed by a good chance of showers Monday. Temperatures staying above normal during this period. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/...
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As of 135 AM EDT Tuesday... Widespread VFR overnight into Tuesday. Areas of frost are likely in sheltered valleys this morning. Could see KLWB briefly drop down to IFR/LIFR in fog but will not include given uncertainty. Extended Aviation Discussion... High pressure will remain over the region for the week with VFR weather through Saturday.
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&& .RNK WATCHES/WARNINGS/ADVISORIES...
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VA...Frost Advisory until 9 AM EDT this morning for VAZ007-009>014- 018>020. NC...None. WV...Frost Advisory until 9 AM EDT this morning for WVZ042>044-507- 508.
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&& $$ SYNOPSIS...AMS/JH NEAR TERM...JH/KK SHORT TERM...WP LONG TERM...PW/RAB/WP AVIATION...AMS/JH

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