Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 170756 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 352 AM EDT Sun Mar 17 2024 .SYNOPSIS...
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A cold front will cross the region late Sunday, bringing cooler air for the beginning of next week, including freeze potential Monday night.
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&& .NEAR TERM /TODAY THROUGH TONIGHT/...
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As of 352 AM Sunday... Zonal flow over central NC was evident on water vapor imagery this morning. Further north, an upper trough was digging into the upper Midwest. Simultaneously, weak vorticity perturbations embedded within a developing shortwave have generated convection from central TX northeastward through AR. At the sfc, a weak area of low pressure was located near Cape Lookout, with a boundary extending just offshore and south through the Gulf of Mexico. Further northeast, a 1014 mb high anchored off Cape Cod was extending light ssely flow across central NC ahead of a cold front draped across the Ohio Valley. Residual stratus will quickly lift this morning, but additional mid to level cloudiness will blanket the sky as the aforementioned shortwave over the deep south moves through the southeast today. Highs will remain a bit above average again today in the upper 60s to lower 70s. A sfc low associated with the shortwave over TX this morning will push east across the Gulf of Mexico today and scoot by just to our south overnight. Rain chances for our area appear to be quite low today given that 1) the deeper moisture will pool to our south and 2) the better upper and sfc forcing will remain well to our north. Still can`t rule out a few passing showers across the Sandhills and Coastal Plain, but overall expecting a low QPF event. The cold front currently over the Ohio Valley will pass through our area tonight. Swly flow ahead of the cold front may induce some gusts of 10 to 20 mph this afternoon/evening. Additionally, good mixing behind the front will likely support periods of nwly gustiness with frontal passage through early Monday morning. CAA should lag the front, allowing overnight lows to remain in the lower 50s.
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&& .SHORT TERM /MONDAY AND MONDAY NIGHT/...
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As of 352 AM Sunday... Deep mixing behind Sunday night`s cold front should allow for gusty nwly sfc flow (15 to 25 mph at times) and considerably drier air to move across central NC Monday. Strong CAA and periods of cloudiness will limit daytime heating as high temperatures struggle to reach the mid to upper 50s. Aloft, a strong upper trough will move over our area Monday night into Tuesday morning. Forecast soundings indicate additional stronger gusts and CAA may accompany it`s passage promoting chilly overnight lows upper 20s to mid 30s. Given that the growing season has officially began for our southern Piedmont locations, decided to issue a Freeze Watch for Stanly, Montgomery, Lee, Anson, and Richmond counties. Probabilities for sub-freezing temperatures in these counties amongst varying ensembles are high enough to necessitate the watch. Regardless of your location and associated official growing season start dates, make sure to protect any sensitive vegetation Monday night. Lastly, a few sprinkles or isolated showers may accompany the passing of the upper trough early Tuesday morning.
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&& .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 320 AM Sunday... Overview: Cool and dry early-week weather will rebound back closer to normal temps by mid to late week. The late-week rain chances that appeared fairly certain yesterday are now much less clear, with recent models exhibiting varied solutions in terms of sensible weather, leading to lower-than-usual confidence for Thu-Sat. Tue-Wed: The potent mid level shortwave trough will have shifted offshore by Tue morning, although another much weaker perturbation will shift ESE through NC Tue afternoon. Our dry NW steering flow will then slow and back gradually through Wed night, while the persistent closed low over AZ finally opens a bit and tracks E through NM to OK/N TX. At the surface, our incoming chilly high initially centered over E TX will expand eastward across the Deep South/N Gulf/FL through Wed, while moderating, as noted in model forecast low level thicknesses which improve from about 50 m below normal Tue morning to just 10 m below normal Wed morning. After a frigid start Tue, temps should peak around 10 deg below normal, in the 50s, despite plenty of sunshine. Fair skies and light winds with decoupling Tue night should yield good radiational cooling, but guidance still suggests that only outlying/rural areas of the Piedmont and W Sandhills have a risk of near-freezing temps, while the majority of central NC will see lows in the mid 30s to around 40. Expect a seasonably mild Wed with highs in the mid 60s to lower 70s under mostly sunny skies. Operational models and the LREF do bring an Arctic cold front in backdoor fashion SSE into or through NC Wed night, driven by a passing shortwave trough through the Northeast states and incoming dense air associated with a cold high pushing from Manitoba/W Ontario into the Upper Midwest/Great Lakes. Thus, our temps should drop back below normal Wed night, esp across the N, with lows from the mid 30s near the VA border to the low-mid 40s S. Thu-Sat: Forecast confidence declines late in the week. As the Arctic trough lifts NE into the Canadian Maritimes, with a portion of the high to our north shifting over and off the Mid Atlantic coast, we`ll be left primarily under the influence of the southern stream, with our forecast hinging on the mid-upper shortwave trough tracking from OK/N TX across the Gulf states and to the Southeast coast through this period. Over the last 24-36 hrs, the ECMWF/ENS and the EC-based ML models have trended toward significant dampening of this wave as it moves into the Gulf states and Southeast, such that they are largely dry for NC during this period, with only the GraphCast ML model with light precip in S NC while the ECMWF/ENS and other ML models keep us dry, except near and off the Carolina coast. The GFS/GEFS/Canadian/GEPS, meanwhile maintains a sufficiently robust shortwave trough moving through the Gulf/Southeast states and off the Southeast coast during this period with rain chances spreading over the Carolinas due to the increasing long fetch of Atlantic moisture spreading NW into NC. With these latter model clusters along with the NBM output still depicting rain chances, esp over our SE, from late Thu night into Sat (peaking Fri/Fri night), will maintain pops during this time frame but hold them at chance, modestly above climatology. Expect near normal temps Thu with increasing clouds, then slightly below normal Fri/Sat with mostly cloudy skies and rain chances. -GIH && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... As of 148 AM Sunday... Periods of MVFR to IFR stratus will continue KRDU, KFAY, and KRWI through early to mid morning. Additionally, some reduced visibilities via fog will be possible at KFAY/KRWI between ~6 and 10Z. Conditions at these terminals should lift to VFR by early to mid-morning. Otherwise, swly sfc flow will pick up a bit in the afternoon gusting to 10 to 20 kts at times. Mid to high level cloudiness will increase ahead of an approaching cold front which will pass through the area later tonight. A few showers may scoot by late in the TAF period, but overall expect mostly dry conditions today and tonight. Outlook: Another cold front will clear the area Sunday night into Monday, behind which, gusty nwly flow will develop Monday. VFR conditions are then expected through the remainder of the outlook period. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Kren/Luchetti NEAR TERM...Luchetti SHORT TERM...Luchetti LONG TERM...Hartfield AVIATION...Luchetti

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