Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 140022 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 722 PM EST Wed Dec 13 2017 .SYNOPSIS... A fast moving upper level disturbance will move just north of the region tonight, and will be followed by a weak surface cold front that is expected to pass across central North Carolina Thursday morning. High pressure will then build into the area by late Thursday. && .NEAR TERM /THROUGH TONIGHT/... As of 652 PM Wednesday... Little if any changes required to the near term forecast. A fast moving upper disturbances and attendant sfc front will cross central NC overnight-early Thu. While system currently producing a notable deck of mid level cloudiness across the central Appalachians, system moving into a very dry air mass. Thus, should see some cloudiness with the system later this evening through 2 AM but likely not to the extent currently being observed to our northwest. Due to the dry air mass, especially below 10000ft, not expecting any precip with this system across our region. The increasing clouds and a steady sly sfc wind will cause temperatures to slowly cool. Once the clouds depart overnight, temperatures will likely drop to near or below freezing by daybreak. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... As of 248 PM Wednesday... Fair weather is in store for Thursday in the wake of tonight`s departing short wave trough and the sfc cold front continuing to push south of our area. With the upper flow becoming westerly, look for the high clouds currently located over the central Plains to gradually move eastward and across our area. Otherwise, with low level thicknesses remaining close to their pre-frontal values (some 30-40m higher than today), we should see highs at least 8-10 degrees warmer than today. Overall, Thursday will be partly cloudy with highs in the lower 50s. Thursday evening the low level wind field will shift to the N/NE as high pressure over the Ohio Valley moves east. Although low level thicknesses may drop a few meters on this N/NE flow...increasing high clouds from the southwest should offset the cooler airmass. Lows in the upper 20s to around 30 under partly cloudy skies. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... As of 255 PM Wednesday... A strong upper short wave moving across the Ohio Valley will nudge a reinforcing surge of cold air into the area. Surface high pressure will then build across the area, resulting in plenty of sun, but suppressing high temperatures to the 40s Friday and Saturday. Morning lows Saturday will be mostly upper 20s, with some areas across the south only falling to near freezing. Short wave ridging will be amplifying north into the Eastern Conus by Saturday night, with increasing heights and initiation of warm air advection in return flow as the surface high moves offshore. Cloudiness will be on the increase by later Sunday with highs reaching mostly low and mid 50s after a morning low near freezing. By Monday, a low pressure area will be lifting northeast out of the Gulf of Mexico. There is a good deal of uncertainty as to how the details will play out, with model timing issues as the ECMWF has a strong fast moving short wave race across the Ohio Valley to kick the system offshore quickly, resulting in precip pretty much limited to the southeast, while the GFS`s slower short wave allows for a couple of waves to ride up the upper ridge into the area to produce more widespread precip and prolonging the duration of precip chances into Tuesday. Will maintain our ongoing forecast of chance PoPs from Sunday night through Tuesday and allow details to emerge from later model consensus. That said, precipitation type will be no problem with southern stream flow into the area allowing highs Monday and Tuesday to reach the 50s after morning lows in the low to mid 40s. Wednesday looks to be a dry and a bit cooler, but still near seasonable in the 50 to 55 range. && .AVIATION /00Z THURSDAY THROUGH MONDAY/...
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As of 722 PM Wednesday... There is a high probability of VFR conditions across central NC through 00Z Friday. A fast moving upper disturbance and attendant sfc front will cross central NC later tonight through early Thu. This system will be accompanied by a deck of mid level clouds with ceilings at or above 10000ft. These clouds will depart prior to 12Z Thu. Through 12Z Thursday, there is a threat for low level wind shear in proximity of KFAY and KRWI as winds just a couple thousand feet above the surface will be swly 35-40kts. VFR conditions are expected Thursday night through Saturday night. Another area of low pressure will affect our region late Thu night through Friday. Ceilings associated with this system are expected to remain VFR. A low pressure system approaching from the west may bring a threat for sub VFR ceilings to central NC late in the weekend.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...np NEAR TERM...WSS SHORT TERM...np LONG TERM...mlm AVIATION...WSS

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