Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 150557 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 1250 AM EST Sun Jan 15 2017 .SYNOPSIS...
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A cold front will drop southward across central NC today. High pressure will build in behind the front and reinforce a cold air damming airmass over the area through Monday night.
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&& .NEAR TERM /THROUGH TONIGHT/... As of 845 PM Saturday... The low-level west-northwesterly downslope flow east of the mountains has helped to disperse and erode the low-level moisture associated with Saturday`s cold air damming regime across the NC Piedmont. Weak shortwave impulses embedded in the westerly flow aloft will interact with the ribbon of mid-level moisture laying atop the region, producing partly to mostly cloudy skies overnight with the slightest chance of some sprinkles across the far northern zones. Wedge boundary over upstate SC is forecast to lift back north into southern portions of the forecast overnight/towards daybreak, which could yield slight warming across the southern counties, while central and northern counties will either hold steady or just cool slightly. Min temps ranging from lower 40s north to mid/upper 40s south. Additionally, with the boundary lifting north into the area, could see some areas of fog develop, possibly dense in some spots. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM Saturday... Sunday, a strong s/w will cross southern New England/northern Mid- Atlantic region. The sfc cold front attendant with this feature will enter our northeast counties by early afternoon and drive southwest, exiting our southern Piedmont shortly after sunset. Similar to the last frontal passage, very little if any rain will occur ahead or along the front. In fact, skies Sunday will be variably cloudy with peaks of sunshine probable, especially across the Sandhills and southern coastal plain. This may lead to a wide range in high temperatures Sunday afternoon, varying from near 50/lower 50s far northeast to the lower 60s southwest. if sunshine is more prevalent than current thinking, afternoon temps may end up 3-5 degrees warmer than forecast. Sunday night, a dry air sfc ridge will build south along the Carolina coast. Meanwhile the the flow in the 925-850mb layer will be veering to a south-southwesterly direction as a waa regime commences. This will lead to the development of another stratus layer along with patches of light rain, primarily over the western Piedmont. This set-up will initiate a hybrid cold air damming event. Min temps Sunday night will vary from the upper 30s northeast to the low-mid 40s southwest. && .LONG TERM /MONDAY THROUGH SATURDAY/... As of 300 PM Saturday... A 1030-1032 mb surface high will settle over the New England coast Monday resulting in a CAD wedge over northern and western NC. The high will shift off the Mid-Atlantic coat Monday night, but the wedge will remain over northwest portions of the area through Tuesday, as the return flow from the high offshore and increasing southerly flow ahead of the approaching front won`t erode it before then. Meanwhile aloft, the closed low over the Baja will swing northeast into the Midwest by Monday and toward the Great Lakes through Monday Night. The aforementioned low will get absorbed in the northern stream Tuesday while a lingering trough/low remains of the southwest U.S. The strength of the low/shortwave as it moves through the Great Lakes and the high ridging over the southeast U.S. will play an important part in how the weather plays out over Central NC Tuesday through Thursday. It is even uncertain at this time when the actual frontal passage will occur. Given all the uncertainty, the forecast confidence is very low at this time, with respect to both temperatures and precipitation. The secondary southern stream low will progress eastward Thursday through Saturday as a strong upper low approaches the Northwest U.S. coast, digging a very deep trough over the western U.S. Although confidence is low, it does appear that another round of precipitation will occur as the low moves eastward in the Mid- Atlantic late in the week/early weekend, but exactly when and how much is far to uncertain to specify at this time. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/...
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AS OF 1250 AM Sunday... Pretty high confidence in VFR early this morning, with clouds at 6- 8k ft drifting east across the area and a chance of MVFR/IFR vsbys between 09z and 12z, especially at FAY. A cold front will surge south across the area between 15z and 21z today, causing the currently light and variable winds to become northeasterly at 6- 10kt. Models have struggled with this weather pattern the last couple of days, and seem to still be in disagreement on how quickly MVFR ceilings will redevelop, but recent trends suggest some scattered MVFR ceilings this afternoon and then a better chance of cigs lowering at FAY/INT/GSO/RDU after 00Z. RWI may stay VFR through the period. Outlook: Conditions are expected to at least MVFR by 12Z Monday, and more likely IFR at INT/GSO, as southerly flow reinforces a cold air damming airmass over the area. Low cigs should persist into Tuesday, when there will be a chance for low clouds to scatter ahead of a cold front approaching from the west. The cold front and associated rain and low cigs/vsby will should impact the area Wednesday. VFR Conditions will return to all terminals in the wake of the cold front Wed night and Thursday.]
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&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS NEAR TERM...CBL SHORT TERM...WSS LONG TERM...KCP AVIATION...Smith

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