Area Forecast Discussion
Issued by NWS Newport/Morehead, NC

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280 FXUS62 KMHX 300658 AFDMHX Area Forecast Discussion National Weather Service Newport/Morehead City NC 258 AM EDT Tue Apr 30 2024 .SYNOPSIS...
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A weak cold front will move through the area on Wednesday. High pressure then builds in for a couple of days before yet another cold front impacts the area over the weekend.
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&& .NEAR TERM /TODAY/...
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As of 200 AM Tuesday... Mid/upper level ridging will shift offshore today as a shortwave shifts east out of the TN Valley. Despite continued low-level moisture advection, the combination of residual subsidence and warm temps aloft are expected to keep the risk of showers at a minimum again today as the seabreeze moves inland. Yesterday the chance of showers was close to zero. Today it will be about 5-10%. Once again, temperatures this afternoon will top out in the mid 80s inland(~10 degrees above normal), and the 70s along the coast (close to normal).
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&& .SHORT TERM /TONIGHT/...
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As of 200 AM Tuesday... SFC low pressure is forecast to pass south of Southern New England tonight, with an associated weak frontal boundary moving slowly east from the Appalachians to the Carolinas and Virginia. A modest LLJ is forecast to develop ahead of the advancing front, with steady low- mid level moistening expected through the night. Mid-level lapse rates will be weakening with time, but a deepening layer of moisture appears supportive of a zone of weak instability (250-500j/kg MUCAPE) developing ahead of the front and an upper level shortwave approaching from the west. Large-scale forcing for ascent is forecast to be on the weak side, but a weak coastal trough moving inland plus modest low-mid level convergence appears supportive of scattered showers and thunderstorms developing from coastal SC northeast through SE NC after midnight. Weak effective shear (~20kt) and weak instability is expected to limit any severe weather potential tonight. Where thunderstorms manage to develop, rainfall amounts as high as 0.25-0.50" will be possible. Otherwise, amounts are forecast to be less than 0.10". With increasing clouds, and steady boundary layer moistening, temperatures tonight are expected to be very mild for late April, only dropping into the mid 60s. For perspective, normal lows this time of year are in the mid to upper 50s.
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&& .LONG TERM /WEDNESDAY THROUGH MONDAY/...
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As of 330 PM Monday... KEY MESSAGES - Low to mid 80s for the rest of the week - Best rain chances Wednesday and then this weekend FORECAST DETAILS With a disturbance expected to pass during Wednesday`s peak heating, showers and thunderstorms are possible across the area (30-55% chance). Although thunderstorms are possible, severe storms are less likely as very little shear is expected. Thursday has trended drier for showers and thunderstorms with PoPs below slight chance. Temperatures will remain high with upper 80s inland to mid to upper 70s along the coast. A little more moisture advection Saturday and Sunday with both the Bermuda High and an approaching frontal system from the west contributing to the increase in precipitable water. Increasing chances for rain and thunderstorms (35-40%) by Saturday afternoon and then lingering into Sunday as the front moves into the region. Temperatures slightly cooler both days but still well above normal for this time of year.
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&& .AVIATION /07Z TUESDAY THROUGH SATURDAY/...
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SHORT TERM /through 06z Wednesday/... As of 145 AM Tuesday... KEY MESSAGES - Sub VFR conditions possible overnight (30-50% chance) FORECAST DETAILS The main forecast challenge over the next 6-8 hours will be the potential for BR/FG/low stratus. With high pressure offshore to the southeast of Eastern NC, a moistening low-level flow is ongoing from the Atlantic into the Carolinas. Within this flow, there is evidence on satellite imagery of some attempt at FG or stratus from coastal SC north into SE NC. While moisture advection overnight is expected to be stronger than this time 24 hrs ago, it`s still unclear whether or not the depth of moisture will be sufficient for impactful sub- VFR conditions or not. For now, I`ve kept the TAFs as-is, with no changes to the 00z TAFs (regarding the fog/stratus potential). Stay tuned for amendments if needed. Any fog or stratus that develops is expected to mix out with daytime heating on Tuesday. During the day Tuesday, gusty S to SW winds up to ~20kt are likely with daytime mixing and the passage of the seabreeze. With increasing moisture, I expect more cumulus with the seabreeze today, but the risk of SHRA still appears low (<10% chance). Late Tuesday evening, continued moisture advection is expected to lead to the development of mid-level CIGs ahead of an upper level wave approaching from the west. There will be a chance of SHRA and TSRA with this wave, but not until after the current 06z TAF cycle. LONG TERM /Wednesday through Saturday/... As of 330 PM Monday...Pred VFR expected through the period. An approaching disturbance will bring some chances for precipitation Wednesday and Thursday afternoons.
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&& .MARINE...
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SHORT TERM /through tonight/... As of 200 AM Tuesday... Background northeasterly long-period swell continues through tonight, and will combine with a modest southerly wind swell, producing seas of 3-5 ft. Like yesterday, breezy southwesterly winds of 10-20kt will be common through tonight, with a few gusts to near 25kt where the thermal gradient in maximized. Because of the marginal nature of the winds, we`ll continue to run headline-free. Late tonight, an upper level disturbance and a developing weak coastal trough is expected to support an increasing risk of showers and thunderstorms, especially for the southern waters/rivers/sounds. LONG TERM /Wednesday through Saturday/... As of 330 PM Sunday... KEY MESSAGES - Good boating conditions expected early this week FORECAST DETAILS High pressure will shift offshore early this week, with inland troughing developing in the lee of the Appalachians. Winds will steadily increase early next week with southwesterly flow of 10-20kt common. Seas of 3-5 ft will be common through early next week, setting up good boating conditions for several days.
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&& .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...None. && $$ SYNOPSIS...MHX NEAR TERM...RM SHORT TERM...RM LONG TERM...OJC AVIATION...RM/OJC MARINE...RM/OJC