Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 190500 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 100 AM EDT Mon Jun 19 2017 .SYNOPSIS...
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A hot and humid air mass will remain in place today. This occurs as a cold front will push into the region later today and tonight. The front is expected to stall over eastern NC on Tuesday and Wednesday.
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&& .NEAR TERM /Today through tonight/... As of 945 PM Sunday... Latest surface analysis shows a well defined cold front extending from Lake Erie southwest to KIND and KMEM. A surface trough was noted from upstate SC southward into southwestern GA. The air mass across central NC remains weakly to moderately unstable with SPC analyzed MLCAPE values of 1000-1500 J/Kg with surface dew points ranging from the mid 70s across the Coastal Plain to the lower 70s across most of the remainder of the CWA. Despite the instability, convective coverage and intensity has been meager today. Warm mid levels as noted with the 500 hPa temps of -6 to -7 and mid-level lapse rates of only 5.5 deg C/km have largely suppressed convection. Widely scattered storms developed this afternoon with a few gusts between 30 and 40 MPH and a good amount of lighting. These storms produced a plethora of outflow boundaries which largely failed to redevelop convection. Water vapor imagery and NWP both note the presence of multiple disturbances aloft across southwestern VA, western NC & SC into eastern GA with these features expected to translate east and northeast overnight. Latest regional radar shows a very broken line or smattering of convection associated with the upper air disturbances and the surface trough. While the diurnal timing is becoming less favorable, isolated to widely scattered convection is possible overnight as these features pass through with the greatest coverage across the western Piedmont through and just after the midnight hour across the western Piedmont. While the convection will be unorganized and generally weak, the presence of 1000+ J/Kg of DCAPE across almost all of central NC suggest some stronger localized wind gusts are possible. Otherwise, mostly clear skies this evening will give way to the development of areas of stratus and mostly cloudy skies by morning. It`ll be muggy with lows between 70 and 75 degrees. -Blaes && .SHORT TERM /Tuesday and Tuesday night/... As of 230 PM Sunday... Low pressure over the Great Lakes will help to move a cold front closer to the area on Monday. This will cause an increase in precipitation chances Monday afternoon and evening as moisture transport increases ahead of the front, combining with diurnal heating to bring chance to likely PoPs into the region late Monday and early Tuesday. Lift will be aided by the right entrance region of an 850 mb jet over the northern portion of the CWA. This will be coupled with the greatest mid-level vorticity moving through the CWA during peak heating hours. The best upper level dynamics will stay well to the north of the area however, making this a good, but not great setup for severe weather. The day 2 outlook from SPC has a slight risk for severe weather in the northwest piedmont with a marginal risk across the rest of the CWA. The most likely threat will be damaging winds with storm mode likely being multi-cellular or line segments based on bulk shear values of 20-30 kts. While some organization to storms is possible, hodographs are not particularly conducive to rotation and 0-1 km shear and helicity are both fairly low at 10 kts and less than 100 m2/s2 respectively. While freezing levels remain high, better organization of updrafts could mean some better chances for severe hail but still much less likely than severe wind. Expect precipitation to continue through Monday night and into Tuesday as the front slows to a crawl. This will keep good rainfall chances in the forecast through the middle of the week. High temperatures Monday in the mid to upper 80s with lows in the upper 60s to lower 70s. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/...
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AS OF 100 AM Monday... With the main front expected to stall over eastern NC, there should be enough drying in the atmosphere to suppress convection especially across western and northern sections of NC. The close proximity of the front in the SE supports the continuation of at least a chance of showers and thunderstorms in the south and east Wednesday afternoon into the evening. Temperatures will be a bit cooler again Wednesday, but highs in the mid 80s give or take a few degrees appear on target. Lows in the mid to upper 60s are expected again Wednesday night, with lower 70s in the SE. Deep moisture is expected to return quickly from the south on Thursday as high pressure builds in the western Atlantic, and the return flow around the high will bring the surge of deep subtropical moisture back with dew points again in the 70s. Once the moisture returns, the chance of showers and thunderstorms will increase again with 50-70 POP warranted Thu-Fri. Highs will warm back into the 85- 90 range with lows in the upper 60s to lower 70s both days. Showers and thunderstorms appear to likely continue Friday through Sunday with a very moist flow mid/upper flow, very moist boundary layer, and a cold front (or two) making runs toward the region, likely stalling before pushing deep into central NC. So, a continuation of high POP`s, and eventually a flood or flash flood risk may evolve if the current QPF of 2-4 inches materializes into the late week and weekend.
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&& .AVIATION /00Z Monday through Friday/... As of 845 PM Sunday... 24 Hour TAF period: Stronger diurnal showers and storms have weakened with sunset, but approach of a short wave in the deep southwest flow will continue to spawn widely scattered showers and a few storms overnight. Won`t be including in the TAF`s as timing is very low confidence as well as the small number of showers making it unlikely that the airports will see one breeze through. Do expect a recurrence of stratus after midnight in the muggy airmass. Pressure gradient will hinder development of fog, and the height of the stratus deck is expected to be around the 1000 foot IFR/MVFR changeover point. Showers will begin to ramp up fairly early in the west ahead of an approaching front tomorrow, with fairly good coverage of thunderstorms at the GSO/INT sites by early afternoon, and a couple of hours later (20-21Z) over eastern sites. Can`t pin down a high-confidence window of thunder at this point, and will have VCTS in the TAFS for the final 6 hour (18-00Z) time frame. Long term: The front approaching central NC tomorrow will linger in the area, most likely over the east, through Wednesday. Uncertainty surrounding a low pressure center coming out of the Gulf of Mexico leaves a low confidence forecast for the end of the week. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Badgett NEAR TERM...Blaes SHORT TERM...Ellis LONG TERM...Badgett AVIATION...MLM

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