Area Forecast Discussion
Issued by NWS Newport/Morehead, NC
Issued by NWS Newport/Morehead, NC
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191 FXUS62 KMHX 161427 AFDMHX Area Forecast Discussion National Weather Service Newport/Morehead City NC 1027 AM EDT Mon Sep 16 2024 .SYNOPSIS... An area of low pressure to our south will slowly strengthen today as it drifts northwards towards the southern NC coast. There is potential that this low becomes a Tropical Storm today before it makes landfall. Troughing will remain over the Eastern Seaboard through next week as well keeping unsettled conditions across ENC. && .NEAR TERM /TODAY/... As of 10:25 AM Mon...There are no major changes to the forecast with the mid-morning update. Primary forecast focus this morning continues to be Potential Tropical Cyclone #8, currently about 160 miles SSW of Cape Lookout. The system itself has moved little this morning, stuck in weak steering currents south of a sprawling mid-level ridge over New England that has moved little over the past several days. The system will gradually gain speed to the northwest today as it gets picked up by the upper ridge, and the center is forecast to cross inland over northeastern SC this afternoon. Regardless of whether the system is tropical or not, the expected impacts for eastern NC have changed little from the previous forecast. Impacts from PTC 8 are already beginning as its associated rain showers approach the Crystal Coast, expected to steadily encroach northward as the low drifts towards the coast. Winds continue to slowly climb and will peak by early this afternoon. The hazards with this system are multifaceted and include: - Flash Flooding: Very heavy rainfall will fall from this storm as PWATs soar to 2-2.25" today. The forecast axis of heaviest rainfall, per the 00z guidance suite, has shifted slightly westward and is now focused over Cape Fear and far northeastern SC. Consequently, storm total rainfall has trended down modestly for ENC with an area-wide 2-3 inches, while south and west of Highway 70 3-6 inches with isolated higher amounts are forecast. This aspect of the forecast remains fluid as uncertainty over track and intensity lingers, and for that reason a broad Flood Watch is being maintained for the entire FA. Highest likelihood for flooding issues remains focused south of Highway 70. - Coastal Flooding: The coastal flooding threat remains largely unchanged from yesterday, with the potential for up to 3 feet of water AGL in low lying areas. See the TIDES/COASTAL FLOOD section for more details. - Tornadoes: The current forecast track of PTC 8 over northeastern SC brings the tornado-favorable right front quadrant across eastern NC. The highest low level helicity will be displaced to our west, along the I-95 corridor, but 0-3 km SRH of 100-250 m2/s2 combined with afternoon CAPEs between 500-1000 J/kg support at least an isolated risk of a brief tornado especially this afternoon and early evening. - Strong Winds: Winds will strengthen to 30-40 mph along the coast today, especially south of Ocracoke Island. Sporadic wind gusts up to 50 mph are possible in passing rain bands. These may cause sporadic power outages and/or tree damage. Clouds and rainfall will keep temperatures flat and below average for mid-September, with highs in the low to mid 70s. && .SHORT TERM /TONIGHT/... As of 400 AM Mon...The surface low will continue to accelerate northwestward overnight into Tuesday morning around the periphery of the upper ridge. Guidance shows the system will begin to entrain some drier air over inland areas with deeper moisture focused over the Outer Banks, and this is where the band of heavier precipitation will be focused for the overnight hours. Total rainfall overnight will range between 1-3 inches posing a marginal flooding risk. Winds will drop off quickly through the evening as the pressure gradient weakens behind the low. && .LONG TERM /TUESDAY THROUGH SUNDAY/... As of 400 AM Mon... Eastern North Carolina will remain unsettled through the entire period as an impactful low moves out of the area Tuesday. Beyond that, troughing over the Eastern Seaboard will continue to bring daily chances for showers and thunderstorms across the region into next weekend. Tuesday...The low lifts further inland tomorrow, eventually lifting north of the region by Tue afternoon allowing for much more benign weather to finally begin to overspread ENC although shower activity is likely to linger across OBX through the day. Expecting below avg temps across ENC with highs only getting into the 70s to low 80s while lows get down into the 60s to low 70s. Wednesday into the weekend... Previously mentioned upper trough will remain over the Eastern Seaboard through the end of the week while at the surface previously mentioned low is forecast to be to the north and likely dissipated. As we get into the weekend, there remains uncertainty with the forecast as the upper trough over the Eastern Seaboard is forecast to cutoff into an upper low as upper ridging builds across the Northeast. As is typical with upper lows, spread in timing and depth of the feature remains large and forecast confidence remains below average. Either way, daily chances for showers and thunderstorms will remain possible across ENC into the weekend as favorable troughing remains overhead. Continued onshore flow will keep clouds around the region while temps remain at or below avg. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... SHORT TERM /through 12z Tues/... As of 730 AM Mon...As expected, flight conditions are beginning to deteriorate as band of heavier rain, displaced north of a poorly organized low offshore, migrates inland. Prevailing MVFR cigs are in place and will prevail through much of the day, but periods of IFR are probable in heavier rainfall which is expected to peak this afternoon and evening. Synoptic winds will gust up to 20-25 kt, but gusts up to 40 kt are possible in stronger bands of rainfall. MVFR conditions will trend towards IFR after sunset as the low migrates inland and winds weaken slightly. LONG TERM /Tuesday through Friday/... As of 405 AM Mon...Continued unsettled weather will bring a chance for sub-VFR conditions across ENC tomorrow as a low pressure system moves out of the area. After the low moves to the north we will still see at least a low end threat for the rest of the week for sub- VFR conditions as daily chances for afternoon and evening showers and thunderstorms will remain. && .MARINE... SHORT TERM /Today and Tonight/... As of 410 AM Mon...Dangerous boating conditions ongoing this morning as winds remain strong on the northern periphery of an area of elongated low pressure a couple hundred miles south of Cape Lookout. This low may become a Tropical Storm later today, and NHC is continuing advisories on it as PTC (Potential Tropical Cyclone) #8. Regional observations show northeasterly winds of 15-25 kt, with seas ranging 8-12 feet. Little change was made in the forecast. Strongest winds will be focused over Onslow Bay and southern Raleigh Bay this morning and afternoon with gusts up to 35-40 kt. Farther north, forecast winds have decreased slightly but still peak at 20-25 kts with a few gusts up to 30 kt. Winds will likely peak this afternoon, then subside as the low shifts onshore and fills. Seas will continue to be quite hazardous today, peaking at 10-15 ft. Conditions begin to slowly improve into Tues morning. LONG TERM /Tuesday through Friday/... As of 415 AM Mon...Dangerous marine conditions continue into Tuesday, but gradually improve from south to north with winds easing down to 15-20 kts with gusts up around 20-25 kts by Tue morning and veering to a SE and eventually SW direction while seas fall down to 5-8 ft along our coastal waters. Winds and seas fall even further Wed with winds remaining S`rly at 10-15 kts while seas along our coastal waters finally lower down to 3-5 ft by Wed morning. This should then end SCA criteria across all waters with more benign boating conditions forecast for Thurs. Daily chances for showers and thunderstorms will remain possible through the period with locally enhanced winds and seas possible within the strongest storms that may develop. && .HYDROLOGY... As of 415 AM Mon...Widespread heavy rain is expected late today through tomorrow as poorly organized low pressure drifts northwestward towards the coast of South Carolina. Abundant tropical moisture with this system will lead to extremely heavy rainfall rates over areas that have become saturated over the last week. Where the heaviest rainfall sets up remains uncertain due to larger than average spread in model guidance, but confidence in heaviest rainfall remains highest along and south of US 70 where storm total 3-6 inches of rain is possible. Higher isolated totals are possible in stronger rainbands. A more widespread 2-3 inches is forecast for the rest of ENC. && .TIDES/COASTAL FLOODING... As of 420 AM Mon...There will be potential for coastal flooding of up to 1-3 ft AGL today as winds slowly strengthen in association with a poorly organized low pressure system to our south over the Gulf Stream which has the potential to become a Tropical Storm later today. Additionally, coastal flooding may be worsened due to the astronomically high tide cycle we are entering. Ahead of this system, strong ENE/E winds will buildup water along the SE portion of the Pamlico Sound as well as the Neuse, Bay, and Pamlico Rivers. Oceanside, high water levels in addition to strong wave run up will likely produce ocean overwash along NC 12 on the Outer Banks at times of high tide. Additionally with this system we can expect a high threat of rip currents, rough and dangerous surf/shore break, and beach erosion. Current Coastal Flood and High Surf headlines are in good shape, and no changes were made for this morning`s forecast package. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...Tropical Storm Warning for NCZ195-196-199. Flood Watch through Tuesday afternoon for NCZ029-044>047- 079>081-203>205. Coastal Flood Advisory until 8 AM EDT Tuesday for NCZ080-094- 194>196-199. Flood Watch through Tuesday morning for NCZ090>092-094-193>196- 198-199. Beach Hazards Statement until 8 PM EDT this evening for NCZ195- 196-199-203>205. High Surf Advisory until 8 AM EDT Tuesday for NCZ195-196-199- 203>205. Coastal Flood Advisory until 11 PM EDT this evening for NCZ203>205. MARINE...Small Craft Advisory until 8 AM EDT Tuesday for AMZ131-135>137- 230-231. Small Craft Advisory until 8 AM EDT Wednesday for AMZ150-152. Tropical Storm Warning for AMZ154-156-158. && $$ SYNOPSIS...MHX NEAR TERM...MS/OJC SHORT TERM...MS LONG TERM...MS AVIATION...MS MARINE...MS HYDROLOGY...MHX TIDES/COASTAL FLOODING...MHX