Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 210745 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 342 AM EDT Wed Jun 21 2017 .SYNOPSIS...
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Bermuda surface high pressure will extend westward over the Carolina`s today into Thursday. A moist southwest flow will continue across the region through late week.
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&& .NEAR TERM /THROUGH TODAY/...
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As of 342 AM EDT Wednesday... The main surface front was becoming ill-defined this morning. Weak lower pressure was located in the lee of the Appalachians, with the dominate feature being the building "Bermuda" surface high. The surface winds have become light SW for many areas. As the high pressure extends westward today over NC, the surface trough will become better defined in the lee of the Appalachians. Some drying aloft (mid and upper levels) is expected today associated with the building upper heights, but the low level moisture is expected to remain high - characterized by dew points in the mid 60s to lower 70s. The best chance of showers should be early this morning. Then later this morning into the afternoon the temporary drying of the mid/upper levels combined with subtle sinking associated with the higher pressure should limit shower chances. However, the latest CAMS do depict a low chance of showers/isolated thunderstorms this afternoon. We will carry likely POP early in the east, chance in the west. Then, reduce POP to 20-30 percent this afternoon. QPF in general, only 0.1 to 0.25 today. Areas of low stratus and fog with a chance of showers to start the day. Then, expect skies to become variably cloudy. Highs again are favored to be in the upper 70s to mid 80s.
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&& .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
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As of 342 AM EDT Wednesday... Mid and upper level moisture is forecast to increase tonight and Thursday as the mid/upper level ridge axis slowly shifts to our NE. As this occurs, a SW flow aloft and slowly falling height will bring moisture and lift back over much of the western two-thirds of NC Thursday afternoon. With stronger heating and more sun expected Thursday, highs will reach the upper 80s to lower 90s in most areas. MLCapes will reach 1500-2000 J/KG during peak heating. Scattered showers and thunderstorms are expected, especially over the western Piedmont where the proximity of the Appalachian lee surface trough will aid moisture convergence/lift.
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&& .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 320 PM EDT Tuesday... Deep southerly-southwesterly flow between newly formed T.S. Cindy that`s currently over the Gulf of Mexico and the subtropical ridge over the western Atlantic, will channel a plume of tropical moisture(PWATS ~2.25")northward into the region as early as Thursday night and could linger over the area until a cold frontal passage late Sunday and into Monday. Model spread remains high, specifically WRT to the timing heavy rain chances and qpf amounts across the Carolinas, largely due to the uncertainty in the interaction/phasing of the northern stream shortwave and the remnant circulation center associated with T.S. Cindy. Given the low confidence, will refrain from getting to specific in forecast details. While we do not expect continuous heavy rain through that period, conditions will be favorable for episodic heavy rain through the period, perhaps initially from the initial surge of tropical moisture and embedded upper disturbances (potentially convectively induced) ejecting NEWD across the region, and then followed by a second or quite possibly even third heavy rain event associated with Cindy`s remnant circulation center/energy aloft and then if separate, with the actual cold frontal passage. Early indicators suggest that central NC could see widespread heavy rainfall amounts of 2 to 4 inches from Thursday night through early next week. Rainfall totals over the past 5 to 7 days are already at 400 to 600 percent of normal across much of the area. Numerous creeks/small streams as well as main stem rivers are running high. Thus, any additional heavy rainfall over the next 5 days will result in prime conditions for both Flash and River flooding. A flood watch may will likely be needed, once better forecast confidence is reached. Highs will be highly dependent on rain chances through the period, ranging from mid 80s to lower 90s. Warm overnight lows in the upper 60s to lower/mid 70s. Cooler drier conditions should follow in the wake of the cold front on Tuesday. && .AVIATION /06Z Wednesday through Sunday/... As of 118 AM Wednesday... IFR conditions are expected to become widespread through 12z, then linger through 15z/today. Areas of rain will taper off through daybreak. A return to VFR conditions are expected this afternoon and tonight. Outlook: IFR CIGS and MVFR VSBYS are expected again between 09Z and 13z/Thu. A return to VFR conditions in general Thursday morning, with scattered MVFR conditions in showers/storms at times late Thursday through Saturday morning. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Badgett NEAR TERM...Badgett SHORT TERM...Vincent LONG TERM...CBL AVIATION...Badgett

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