075 FXUS62 KMHX 130159 AFDMHX Area Forecast Discussion National Weather Service Newport/Morehead City NC 959 PM EDT Tue Jul 12 2022 .SYNOPSIS... A weak coastal trough is forecast to set up just offshore this evening as high pressure dissipates across the Mid-Atlantic tonight. An unsettled pattern will then return beginning tomorrow and continue through the week as a slow moving cold front approaches from the northwest and eventually stalls over the area. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... As of 945 PM Tuesday...Have trimmed back PoPs over the coast through the overnight period with existing showers approaching the FA from the SW quickly dissipating and offshore activity under performing. Have maintained SChc->Chc offshore with Cape Lookout having the greatest chance of being skirted by some showers. The rest of the forecast remains on track. Previous Discussion...Southerly winds continue tonight ahead of an approaching cold front that will reach the western piedmont after midnight. Mainly dry conditions continue inland but could see showers along the offshore coastal trough approach the coast after midnight. Light to moderate southerly winds will prevent fog development and keep min temps several degrees warmer than this morning, mainly in the mid 70s inland to upper 70s coast. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... As of 950 PM Tuesday...Have lowered PoPs during the early morning hours with offshore showers not expected to approach the coast until late morning. Previous Discussion...On Wednesday as the above- mentioned frontal boundary moves into a moistening and destabilizing airmass across ENC we will see our first threat for scattered showers and thunderstorms Wednesday afternoon and evening. While low- level convergence isn't overly strong with this boundary, it should provide sufficient lift for scattered to numerous thunderstorms (aided by modest large- scale forcing for ascent with embedded shortwaves and the entrance region of an upper jet). The combination of modest instability, lapse rates, and deep layer shear should support the potential of a few stronger to marginally severe thunderstorms developing both Wednesday, primarily with a gusty/damaging wind threat. PWats increasing to 2"+ again should also lead to very heavy rainfall rates and at least a few instances of flooding. Given the timing of the expected shower and thunderstorm activity expecting highs to once again get 9into the lower 90s across our inland areas with upper 80s expected along the coast and OBX. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... As of 4 PM Tuesday...The long-term period will feature a very blocky upper level pattern with anomalous ridging developing over both the Great Plains and the western Atlantic. In between these two features, upper level troughing will become established from the Gulf of Mexico to the eastern Great Lakes, with a mostly south to southwesterly flow aloft residing across the Southeast US. Meanwhile, a low-level frontal boundary will move southeast into the area on Wednesday, then more or less meander near/over ENC through the weekend and potentially into next week. Towards the end of the week, the western Atlantic ridge is forecast to shift east some, potentially allowing a pair of upper lows to lift north out of the Gulf of Mexico and/or the western Atlantic. Given the blocky pattern, medium range guidance continues to show significant differences with both of those features and any associated SFC reflection. The key message at this point is that unsettled weather continues on Thursday and potentially lasts well into next week, but with decreased day-to-day confidence by the weekend and into next week. Confidence is higher on Thursday as the frontal boundary moves into a moistening and destabilizing airmass across ENC. While low-level convergence isn't overly strong with this boundary, it should provide sufficient lift for scattered to numerous thunderstorms (aided by modest large-scale forcing for ascent with embedded shortwaves and the entrance region of an upper jet). The combination of modest instability, lapse rates, and deep layer shear should support the potential of a few stronger to marginally severe thunderstorms once again on Thursday, primarily with a gusty/damaging wind threat. PWats at 2"+ again should also lead to very heavy rainfall rates and at least a few instances of flooding. Later in the week, lapse rates and instability weaken some, perhaps leading to more of a scattered to numerous showers/isolated thunderstorm scenario, especially in the more tropical airmass advecting in from the south. In that scenario, the impacts would shift more to heavy rain and less of a damaging wind threat. Temperatures will gradually fall back to a bit below climo through the end of the week as there will be more clouds, showers, and storms around. I continued the theme of likely pops mid-week (when confidence is highest), but then tapered pops back to more of a chance/high chance/scattered type scenario towards the weekend and early next week due to reduced confidence in timing, location, etc. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM /Through Tonight/... As of 720 PM Tuesday...VFR flight cats are expected through the period. Light S/SWerly winds persist through tonight, precluding any fog development. Wednesday, cold front impacts the area with breezy SWerly winds becoming gusty in the afternoon and chance of scattered showers and tstorms increasing through the afternoon. At this time, CIGs are expected to remain VFR Wed with a CU field around FL030 lifting to FL050 through the day. Best chance for sub-VFR flight cats will be due to reduced VIS under showers/tstorms in the afternoon and evening. LONG TERM /Wednesday through Saturday/... As of 300 AM Tuesday...The long-range aviation period will feature an increased risk of SHRA and TSRA and sub-VFR conditions. Highest confidence in TSRA impacts is Wednesday and Thursday, with lower confidence beyond that point. Gusty/erratic winds can be expected where TSRA occur, along with reduced VIS. && .MARINE... SHORT TERM /Through Tuesday/... As of 4 PM Tuesday... A thermal trough across the Piedmont this afternoon continues to bring 10-20 kt S-SW'rly winds across the coastal waters this afternoon. Though the thermal trough will weaken and dissipate this evening with the loss of daytime heating winds will persist at these levels through tonight and into Wednesday as a cold front approaches from the NW. Could see an occasional gust to near 25 kt across the Pamlico Sound and Alligator River this evening before falling to around 20 kts tonight. 25kt gusts will be possible once again Wednesday afternoon as the strongest gradient of the day sets up out ahead of the approaching front. Seas build to 3-5 ft tonight in response to stronger SW winds and remain at these heights into Wednesday evening. LONG TERM /Wednesday through Saturday/... As of 300 AM Tuesday...A general 10-15kt south to southwest flow will prevail for much of the long-term period, with occasional gusts to 20-25kt possible. Local enhancements to winds are possible with any surface wave that moves through, but confidence on any one particular wave is lower for now. Within that southerly flow, increasing moisture and instability will favor an increased risk of showers and thunderstorms just about anytime day or night. Confidence in 4-5 ft seas is highest mid-week, but then confidence lowers beyond that. In general, 3-4 ft seas will be common through the weekend and into next week. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...None. && $$ SYNOPSIS...MHX NEAR TERM...CEB/RCF SHORT TERM...CEB/RCF LONG TERM...RM AVIATION...RM/CEB MARINE...RM/RCF