Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 190841 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 340 AM EST Thu Jan 19 2017 .SYNOPSIS...
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High pressure will build over the region today, then move off the Northeast coast this evening. Surface low pressure and an upper level disturbance will cross the area from southwest to northeast late tonight through Friday morning. Another disturbance aloft will sweep through the region Friday night into Saturday. A powerful storm system will affect the region Sunday into Monday.
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&& .NEAR TERM /THROUGH TONIGHT/... As of 335 AM Thursday... Surface high pressure and an upper level ridge will be in control for the day today. This will result in clear skies, slightly cooler temperatures, and very little wind. High temperatures around 60 degrees. Cloud cover will begin to increase from the southwest this evening as a southern stream system approaches. Precipitation chances will increase for the western Piedmont after 6z and rain should begin before 12z. Elsewhere should remain dry. Lows in the mid 40s. && .SHORT TERM /FRIDAY AND FRIDAY NIGHT/... As of 335 AM Thursday... Rain will continue across central NC on Friday as a disorganized frontal system moves across the area. Rain will continue into the late afternoon or early evening ending from west to east as it does so. Total accumulations of rainfall are expected to be somewhere in the neighborhood of a tenth to a quarter of an inch. Temperatures will be dictated by cloud cover but warm air advection ahead of the system will bring max temps up into the mid 60s across the south, with upper 50s to low 60s across the north. Lows Friday night in the upper 40s to low 50s. && .LONG TERM /Saturday through Wednesday/...
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As of 340 AM Thursday... A wet and somewhat stormy pattern will reach a crescendo late Sun through Sun night as a powerful mid level low and mature surface frontal system impact the region. A drier and quieter weather period will begin late Mon and last through Wed. Sat/Sat night: A subtle mid level wave will sweep NE through the region, accompanied by a slug of upper divergence in the nose of a weak southwesterly low level jet. With PW surging well up above normal, this forcing for ascent should have no trouble producing showers over NC, most numerous across the S and E. A brief lull will follow late Sat afternoon into the evening, however the approach of another stronger perturbation from the SW and an even stronger and extensive low level jet nosing in from the south will prompt a return to widespread rain late Sat night. Highs in the low-mid 60s and lows in the mid-upper 50s with cloudy skies. Sun through Mon night: Widespread rain should be ongoing early Sun, fueled by the aforementioned wave, strong low level mass convergence, and another batch of vigorous upper divergence associated with an upper jetlet on the SE side of the digging low over the Gulf States. This should be followed by yet another short lull in precip coverage and intensity early Sun afternoon, before the powerful mid level low tracks east then northeast across GA and the Carolinas through Mon, bringing numerous showers and storms, peaking Sun evening and night before tapering from south to north Mon as the dry slot wrapping around the low punches in from the south. An uptick in shower coverage is possible Mon afternoon as the core of the mid level low and attendant steep lapse rates drift over the region. Rapidly rising heights as the low shifts to our NNE will induce drying and an end to precip Mon night. A few strong storms remain possible from mid afternoon Sun through Sun evening, with a 70-90 kt mid level jet streak accompanying the powerful upper divergence and steep 700-500 mb lapse rates, topping 7.5 C/km according to the GFS. Timing will be crucial, as the ECMWF is up to 12 hrs faster than the GFS with the arrival of the mid level low. CIPS analog guidance at this range hints at a greater threat for FL, historically speaking, but GFS forecast soundings for central NC showing lengthy wavy hodographs and moderate instability support at least a modest risk of severe storms in our area, including a tornado risk along and north of the occluding frontal system. Highs in the 60s to near 70 Sun, lows from the upper 40s to mid 50s Sun night, and upper 50s to mid 60s for highs Mon. Lows in the 40s Mon night. Tue through Wed: Mid level heights rise over the Southeast as a mid level ridge axis shifts over the region, while surface high pressure crosses the northern Gulf and FL. Expect fair skies with slightly cooler but still above normal temps. -GIH
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&& .AVIATION /06Z THURSDAY THROUGH MONDAY/... As of 120 AM Thursday... VFR conditions across the area this morning will continue overnight will clear skies and calm winds. Dewpoint depressions are high enough that fog is not expected to be an issue tonight. VFR conditions are expected to remain through the entirety of the TAF period. Long term: Another system will move into the area later in the day on Friday and could cause adverse conditions in the form of low ceilings. Precipitation will also be possible. A series of disturbances will keep weather unsettled through the weekend before a more significant weather system moves in on Monday with the potential for some strong thunderstorms. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...RAH NEAR TERM...Ellis SHORT TERM...Ellis LONG TERM...Hartfield AVIATION...Ellis

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