Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 280600 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 100 AM EST Tue Feb 28 2017 .SYNOPSIS... High pressure will push further offshore through this evening, followed by a warm front lifting through the area tonight. A mild flow from the southwest will persist Tuesday through Wednesday, ahead of a cold front that will cross the area Wednesday night. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... As of 900 PM Monday... The 00z GSO sounding hints at a key shift in the forecast this evening and that is extremely dry conditions below 700 mb all the way to the surface. As a result, not much moistening of the atmosphere has occurred and even though isentropic lift will pick up during the overnight hours, having a hard time believing that we will get any precipitation west of US Highway 1. Currently the warm front can be seen in the observations near Columbia SC with an increase in dewpoints of around 10 degrees. Earlier runs of the NAM, WRF and others depicted precipitation forming in the western Piedmont and moving east during the early morning hours as this front pushes northward. Instead, would now favor the HRRR and RAP solutions which show precipitation mainly in the southeastern counties and after 6z and continuing to into the morning with the bulk of the precipitation occurring east of I-95. Expect low temps in the mid 40s in the Triad to low 50s in the southeast. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 AM WEDNESDAY/... As of 320 PM Monday... Tuesday...the isentropic lift will decrease shortly after daybreak Tuesday which should lead to a diminishing of the shower coverage. After 14z, the greatest threat for a shower or two will be roughly along and east of I-95. An increasingly moist and conditionally unstable air mass coupled with the approach of a perturbation lifting east-ne from the TN Valley into the mid-Atlantic Tuesday afternoon will trigger a few additional showers and possibly a thunderstorm. SInce forcing fairly weak, do not expect coverage to be any worse than isolated or scattered. A steady sly flow along with periods of sun should boost afternoon temperatures into the low-mid 70s with upper 70s highly probable across the far southeast. Tuesday night...the mild weather will continue as a low level jet will strengthen overhead in response to an amplifying s/w lifting to our northwest. The variably cloudy skies and steady sly flow will maintain overnight temperatures in the 60-65 degree range, closer to normal daytime highs for early-mid March. While a shower or two may occur to the north-nw of Raleigh and the Triad, the bulk of central NC will remain dry as forcing expected to be weak at best. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... As of 235 PM Monday... Wednesday and Wednesday night: As the low pressure system over the Midwest moves eastward on Wednesday, the parent low will move over the Great Lakes region while the upper level trough/sfc cold front extending from the Great Lakes southwest through the ARKLATEX progress east toward the Carolinas. Over Central NC, continued warm southerly flow will persist through the day Wednesday as cloud cover and chances for convection increase from the west. Highs will range from mid 70s NW to low 80s south. South-southwesterly winds will be quite strong on Wednesday, sustained 15-20 kts with gusts to around 30 kts, strongest just before sunset and then again with the front. Latest model solutions continue to suggest the best chances for convection (shower and possible strong thunderstorms) will move into the west late Wednesday evening, quickly moving eastward through Central NC by early Thursday morning. Despite the poor diurnal timing of the axis of convection the high (uni-directional) shear and low (500-1000 J/Kg) CAPE will result in the slight chance for thunderstorms to produce some damaging winds as they move through the region. The likelihood decreases with time as the showers progress through the area. Wednesday night, winds will become more northwesterly, cold air advection will commence and skies will begin to clear. As a result of current fropa timing, low temperatures will range from mid 40s NW to mid 50s SE. Winds will continue to be breezy overnight (10-15 kts with gusts to around 20 kts). Thursday through Monday: This period is expected to remain dry. Highs Thursday and Friday will still be in the upper 50s to mid 60s, lows Thursday night in the mid 30s. A reinforcing dry cold front will push through late in the week with the coldest temperatures (mid 20s to around 30 degrees) expected Friday night/Saturday morning as the surface high moves overhead. Highs Saturday will be the lowest of the period, mid to upper 50s. Expect moderating temperatures once again for the remainder of the weekend and into next week as yet another low pressure system develops out west and the flow over the Carolinas becomes increasingly southerly. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/...
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As of 100 AM Tuesday... VFR conditions prevail at 06Z/28th as high clouds continue to move east across the area. An area of showers south of CHS should remain confined to coastal SC, but the advancement of a warm front and southeasterly low level flow may bring some MVFR stratus north into southern and western NC. Models seem to indicate late development of MVFR ceilings with fairly thin moisture, with higher confidence at FAY, INT and GSO after 09. there are some MVFR ceilings already developing south of VUJ, which lends some confidence to the forecast through early morning. What stratus that does develop should be quick to disperse and give way to VFR (or near MVFR) ceilings this afternoon and some southwesterly wind gusts to near 20kt). Some showers will be possible near INT and GSO late this afternoon and evening as an impulse and associated convection move through the Tenn Valley and across the mountains, which could result in a brief period of sub-VFR conditions. Outlook: A trend back down to sub-VFR cigs is expected after 06z early Wed morning with a steady breeze from the SW overnight. Low level wind shear (unidirectional) is possible late Tue night through daybreak Wed. Cigs will lift slowly toward VFR through Wed, with a good chance of showers and storms -- some of which could be very strong -- very late in the afternoon through the evening and nighttime hours, ahead of a cold front. Strong and gusty winds from the SW are likely Wed into Wed night, sustained around 20- 25 kts with gusts of 30-40 kts possible. Cold front passage Wed night will shift winds around to NW with clearing skies, and VFR conditions will dominate Thu through Sat. -GIH
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&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...HARTFIELD NEAR TERM...RE SHORT TERM...WSS LONG TERM...KCP AVIATION...SMITH/HARTFIELD

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