Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
Issued by NWS Raleigh/Durham, NC
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034 FXUS62 KRAH 230602 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 102 AM EST Sat Nov 23 2024 .SYNOPSIS... High pressure will build across the Southeast through the weekend, while low pressure will move slowly northeastward from the northern Middle Atlantic and New England coast to Atlantic Canada. && .NEAR TERM /THROUGH TONIGHT/... As of 840 PM Friday... A strong closed core upper low over the NE US will offshore overnight. At the surface, a low pressure system near the Jersey Coast will begin to transfer it`s energy to a rapidly developing and deepening surface low over Nova Scotia. These low pressure systems will keep a tight pressure gradient across the region through Saturday. Winds have dropped off quite nicely to 5-10 MPH across southern and central portions of the area. However, most locations across the north are still gusting in the 17 to 23 mph range. Still expect a shallow, near-sfc based inversion to develop area-wide, but wouldn`t be surprise to see some intermittent gustiness linger across the northern counties into the overnight hours. The perturbed cyclonic flow aloft will result in some periods of scattered to broken stratocu across the north to mostly clear across the south. Lows tonight 35-40, with the steady 5-10 kts deterring and frost formation across the coastal plain and eastern Sandhills where the Frost/Freeze program is still active. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... As of 235 PM Friday... The Northeastern surface low should continue to move up the Atlantic coast towards eastern Canada, and this pattern will allow west- northwest wind to continue across the region. Mostly sunny skies are expected tomorrow, except there could be a little more cloud cover across the Triad. Wind gusts will continue, although values shouldn`t be higher than 20 mph. Highs should be about 10 degrees warmer than today, ranging from the mid 50s to the low 60s. With high pressure settling in across the Southeast tomorrow night, skies will be clear and the wind should significantly drop off, going calm in some areas. Although Saturday night does not look as cold as last night, with temperatures mostly staying above freezing, there will still be frost possible. This will only be highlighted in counties where the growing season has not ended. This area was announced earlier this morning in a Public Information Statement along with maps on social media, generally locations east of US-1. Where the growing season continues, the threat of a widespread freeze appears minimal at this point. Forecast lows across central North Carolina will be in the 30s. && .LONG TERM /SUNDAY THROUGH FRIDAY/... As of 235 PM Friday... * Moderating temperatures to well above average by Tues with a cold front returning near normal temperatures for mid to late week. * Sprinkles and very light rain accompany the frontal passage on Tues, with a better chance for wetting rain Thurs into Fri. Early next week begins with low-amplitude mid/upper level flow over a majority of the CONUS with an area of surface high pressure centered near the FL/GA line. Through the day Sun, high pressure will slip over the western Atlantic ahead of a developing trough over the northern Plains. This trough will gradually deepen as it traverses the Great Lakes and into the Northeast through Tues evening. Cluster analysis suggest the greatest uncertainty with this trough is the speed it translates eastward. Although central NC largely remains removed from the better synoptic forcing, this will have implications on the timing of mid-level cloud cover and light rain, but mostly sprinkles, to move through the area. The most- likely cluster from the 00z cluster analysis suggests a quicker system is favored and would bring clouds and low rain chances to most of the area before the early afternoon. This would mostly impact high temperatures for the day as the overall rain amounts in the 24 hours appear to be minimal (less than a tenth of an inch). The system late in the week will have a better chance for widespread precipitation, but the finer details will still need to be resolved in the coming days. Both the depth of the trough and the timing of its eastward progression result in a great deal of uncertainty. With that said a period of active/wet weather appears likely sometime between early Thurs and Fri evening. Most likely spread in total rainfall (25th to 75th percentile among the grand ensemble) ranges from 0.25 to around 1 inch across the area during the time. Temperatures will climb to well above normal by Tues with a return to near normal behind the fropa. Some degree of in-situ damming appears possible as rain may begin to spread into the area by Thurs. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... As of 100 AM Saturday... A strong, wnwly low-level jet, with winds up to 45-55 kts around 2000 ft AGL and atop a lighter swly surface wind, will favor a continued risk of low-level wind shear until the nocturnal inversion breaks around 14Z and promotes mixing and the redevelopment of gusty wnwly surface winds through this afternoon. Surface winds will diminish at sunset and become mostly calm tonight. VFR conditions are otherwise forecast, with varying amounts of VFR- based cloudiness and with greatest coverage in the form of a blanket of orographically-generated cirrus at INT/GSO from approximately 15- 20Z. Outlook: VFR conditions are expected until a mostly dry cold front moves across the region on Tue, during which time a fleeting MVFR ceiling and light rain will be possible. Low-level wind shear will also likely result ahead of that front Mon night. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...MWS NEAR TERM...CBL SHORT TERM...Green LONG TERM...Swiggett AVIATION...MWS