Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 190259 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 955 PM EST Thu Jan 18 2018 .SYNOPSIS...
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Arctic high pressure will continue to build into the area tonight through Friday morning. This high pressure will shift to our south over the weekend, bringing a milder southwest flow to the area.
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&& .NEAR TERM /THROUGH TONIGHT/...
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As of 955 PM Thursday... Primary change was to nudge low temps upward slightly, based on the current dewpoints and recent pace of temps. The surface ridge continues to extend through central NC from the SW, capped by deep ridging up through the mid levels over the Deep South and into the Southeast. The 00z GSO sounding is quite dry, with dry air upshear at all levels, and highly stable in the lowest 3 km. Dewpoints are in the mid teens to mid 20s in most spots, a bit higher than those indicated by earlier guidance, although recent hi-res runs have caught up to reality. Still expect the coldest temps over the snowpack areas (where dewpoints are lowest). Lows 17-27 under clear skies and with very light winds. -GIH Earlier discussion from 200 pm: Winter Weather Advisory EXTENDED through Noon Friday... Cold high pressure will remain the dominant weather feature through tonight, as the region continues its first attempt to thaw after the snowstorm. Mostly sunny skies and a light to moderate westerly breeze has aided in some melting and evaporation today on low albedo surfaces. However, temperatures have ultimately struggled to surge above freezing, topping out mainly in the low to mid thirties by the early afternoon hours. Looking at latest observation trends, temperatures still seem to be on track to fall short of most guidance this afternoon. Have held steady with our previous forecast, keeping highs near to below 40 degrees. This still may end up being a smudge too high thanks to the modified airmass at the surface. Tonight, expect any improvement on the roadways to quickly revert, with black ice formation likely across much of the areas roadways. Temperatures are expected to plummet below freezing shortly after nightfall, dipping into the upper teens across the northern and western Piedmont Counties with lower twenties prevalent across the Coastal Plains, where there is limited snow pack aiding in low temperature potential. Thus, have extended the Winter Weather Advisory across the majority of central North Carolina through Friday afternoon to account for leftover snow covered roadways Thursday evening along with the expected refreeze tonight.
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&& .SHORT TERM /FRIDAY AND FRIDAY NIGHT/... As of 240 PM Thursday... Underneath strong subsidence/rising heights aloft, the antecedent cP airmass will continue to modify as the parent high over the Deep South Friday morning will further moderate/weaken as it shifts east over the SE US Friday-Friday night. After a chilly start in the teens to lower 20s, high temperatures Friday will rebound to near normal, ranging from mid to upper 40 north to lower 50s south. Another day of full sun combined with these warmer temps will go a long way in helping to thaw/melt snow off the roads and sidewalks. However, good radiational cooling conditions Friday night and antecedent dry air/low dew points in the teens and lower 20s will result in overnights once again down into the 20s, which will cause black ice conditions again on sidewalks, bridges and overpasses. && .LONG TERM /SATURDAY THROUGH THURSDAY/... As of 240 PM EDT Thursday... Southern stream shortwave trough traversing the Deep South will stay south of the area, providing little more in the way of mid/upper level cloudiness across the area Saturday night and into the day on Sunday. Otherwise, afternoon temperatures will continue to moderate through the 50s through the weekend, and even some lower 60s across the southern counties. Depending on just how much cloud cover we see Saturday night, Piedmont counties should see sub-freezing temps once again, ranging from mid/upper 20s NW to lower/mid 30s SE. A deepening storm system will track NE from the Central Plains late Sunday thru the Upper Great Lakes and into Southern Canada by late Monday and into the day on Tuesday, which is coincident with the trailing cold frontal passage through the region. Models currently indicate a band of showers will accompany the frontal passage, but given how far removed central NC is from the better forcing, expect precipitation amounts to be on the light side. Temps are expected to remain above-normal for a majority of the upcoming work week, with the warmest day over next 7 coming on Monday, just ahead of the front. Highs in the upper 50s NW to mid 60s SE. These mild temperatures will then be followed by a brief cool done behind the cold front Wednesday and Thursday. .AVIATION /00z FRIDAY THROUGH TUESDAY/... As of 630 PM Thursday... 24 Hour TAF Period: VFR conditions through the TAF period. An outside chance of some MVFR visibilities overnight, mainly in the Triad but confidence in this is very low. Otherwise, westerly winds will continue through the TAF period at 5-10 kts. Earlier gusts have subsided and are not expected to return on Friday. Long Term: VFR conditions through much of the long term with the next system not expected to affect the area until Monday night into Tuesday. && .RAH WATCHES/WARNINGS/ADVISORIES...
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Winter Weather Advisory until noon EST Friday for NCZ007>011-021>028- 038>043-073>077-083-084-086-088-089.
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&& $$ SYNOPSIS...JJM/GIH NEAR TERM...Hartfield/JJM SHORT TERM...CBL LONG TERM...CBL AVIATION...Ellis

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