Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 240001 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 700 PM EST Thu Feb 23 2017 .SYNOPSIS...
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Strong high pressure aloft will again build over our region through Friday. The ridge will shift east and offshore in advance of a cold front that will cross the area on Saturday. Expect near record warmth ahead of the front, with cooler temperatures on Sunday.
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&& .NEAR TERM /THROUGH TONIGHT/... As of 315 PM THURSDAY... Amplifying mid to upper level ridge will build east into the area in the wake of the closed low moving off southeast Florida coast. Strengthening synoptic scale subsidence will yield increasing sunshine/solar radiation across the area, which in return will scour out the lingering/shallow in-situ wedge in the form of stratus and fog across the NW Piedmont. With the erosion of the in-situ wedge across the NW Piedmont, the warmth that central and eastern sections experienced yesterday will spread to all of central NC today. A projected 10 meter low-level thickness increase will support highs ranging from lower 70s NW to upper 70s SE, which will approach record territory(see climate records below). Lows in the 50s. Cu field has readily developed over the Sandhills/Piedmont fall line, in response to daytime heating and the weak sely onshore flow. CAMs try to develop an isolated shower in this area this afternoon, however with enhanced mid-level moisture moving offshore while remaining capped aloft, expect little vertical growth and thus will keep forecast dry. Good radiational cooling conditions tonight with above normal dewpoint residing over the area will result in rather low dewpoint depressions to support the development of fog, possibly dense in a few locations. Mild overnight lows in the lower to mid 50s. && .SHORT TERM /FRIDAY AND FRIDAY NIGHT/... As of 315 PM THURSDAY... Strong mid/upper level ridging and associated sinking air will combine with strengthening southerly return flow and dry soil conditions to make Friday day two of three of near record warmth across the region. Low-level thicknesses Friday afternoon are forecast to be aoa 1380 meters, which is 50 meters above normal and more representative of late April/early May, as opposed to late February. Highs should approach 80 in many areas, with mid 70s NW. Expect another warm night with an increase in mid and high clouds from the west during the predawn hours as the front progress eastward in the southern and central Appalachians. Lows in the mid to upper 50s, which could challenge record hi-min temps(warmest night). && .LONG TERM /SATURDAY THROUGH THURSDAY/... As of 355 PM Thursday... A cold front will cross the region on Saturday late in the day as a low pressure system moves into Quebec. Since the frontal passage will be later, this will allow high temperatures to soar no near 80 degrees in the southeast with low to mid 70s across the NW Piedmont. Moisture with this system is limited but will be greatest along the VA border. This is where the most rain could be expected which could be up to a half of an inch in heavier showers but the majority of locations will see less than a tenth of an inch. Isolated thunderstorms will be possible along the front as well as there will be some instability but also a cap in the mid-levels to try to overcome. Saturday night skies will clear out and the temperature will drop significantly into the mid 30s to low 40s for overnight lows. Sunday and Monday will be mostly dry as surface high pressure moves over the area with a warming trend for temperatures that will top out in the mid 50s to near 60 degrees on Sunday but climb back into the 60-70 degree range on Monday with coolest temps in the NW and warmest in southeastern counties. Guidance really begins to break down from Monday night really through the rest of the period as differences in timing and intensity of several systems affect the forecast next week. In general, two systems are expected to move across the area, the first a southern stream wave that develops into a low pressure system. Second will be a low over the plains that drags a cold front across the area near the end of the work week. As a result must keep rain chances in the forecast from Monday night onward through Thursday but wouldn`t expect it to rain that entire time. Instead expect one shot of rain and potentially thunder midweek and a second near the end of the week. Future model runs will iron out these differences to give a clearer picture over the next couple of days. && .AVIATION /00Z Friday through Tuesday/...
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As of 700 PM Thursday... Confidence is high in a few-hour-long period of IFR or LIFR conditions tonight into Fri morning, however the precise timing of stratus/fog development is in question. The lack of high clouds favoring good radiational cooling, the weak surface winds, and the increasing low level moisture will all foster formation of low clouds and fog later tonight. Our best estimate, based on latest model trends, is that we`ll see IFR/LIFR cigs/vsbys develop at RWI by 08z, at FAY by 09z, at RDU by 10z, and at INT/GSO by 11Z. These sub-VFR conditions are likely to lift gradually to VFR between 13z and 14z, with VFR cigs possible during the afternoon. Surface winds will be calm or light/variable tonight, becoming from the S or SSW under 8 kts Fri. Looking beyond 00z Sat, VFR conditions should hold through Fri evening, but once again sub-VFR stratus/fog are expected to form across central NC late Fri night, most likely after 08z, and these should trend to VFR before 14z Sat. A few showers and isolated storms are possible Sat afternoon, mainly INT/GSO/RDU, as a cold front crosses the area, however VFR conditions will dominate. VFR conditions will return Sat night, lasting through at least Mon as high pressure builds into and over the region. The chance for sub- VFR conditions and a few showers will return Mon night into Tue as a warm front shifts northward through the area. -GIH
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&& .CLIMATE... Record High Temperatures February 23rd February 24th February 25th GSO 73/1980 79/1982 81/1930 RDU 79/1980 81/1982 82/1930 FAY 80/1922 83/1930 85/1930 && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...CBL NEAR TERM...CBL SHORT TERM...CBL LONG TERM...Ellis AVIATION...Hartfield CLIMATE...RAH

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