Key MESSAGE 1, High pres shifts offshore today while another shortwave swings Eward across the Great Lakes and Mid Atlantic region. This will drag a cold front into the Southeast, but as is typical this time of year, the front gets hung up or at least slows down, before reaching ENC. Isolated to widely scattered showers and storms today, best chances inland this afternoon with the seabreeze though some offshore cells may skirt portion of the OBX. Breezier today as thermal gradient increases in addition to the cold front moving into the Piedmont. Some models indicate some weakening MCS activity arriving into interior ENC this evening, but this activity running into dry air should limit chances to no higher than 30-50% and mainly for our NWern FA. Best chance for a storm would be from around 8pm to 2am. Any storms that enter these areas could be on the stronger side as some renegade instability and shear of 20+ kt will be found here, with strong wind gusts the main threat. Because of this, SPC has the tier of counties furthest inland outlooked in a Marginal Risk (lvl 1/5) of severe storms.
KEY MESSAGE 2, The front will then get kicked through ENC as a backdoor cold front TUE evening as stronger shortwave exits the Mid Atlantic coast. 12z guidance has become more excited for the pressure expected to develop along the boundary, leading to slightly higher chances for more organized deep convection which has resulted in a forecast with higher PoPs, stronger SWerly winds, and greater QPF. Forecast currently advertising likely to categorical PoPs from 1400EDT into the evening hours. Nern zones have highest chances of seeing more organized and strongest storms, where best convergence and forcing will be for more widespread thundershowers. After coordination with neighboring WFOs and national centers, SPC has issued a Marginal Risk of severe thunderstorms (lvl 1/5) for the bulk of the forecast area. Front will sweep offshore around or shortly after sunset TUE. Strongest precip activity will remain ahead of the front and conditions will dry the first half of tomorrow night behind the front, though some wrap around moisture on the backside of the departing low could lead to some lighter showers being pushed from N to S after sunset until around midnight. Dry a relatively cooler conditions (~70/90 split for WED) return for Wed into Thu with high pres dominating. Next chance of showers and storms on Friday as next shortwave swings through the Sern CONUS.
KEY MESSAGE 3, With the return SWerly flow, hot and humid conditions combine to produce uncomfortably warm heat indices, though most likely remaining below heat adv thresholds, with readings in the lower 100s each day early to late week. Brief break from the heat expected on Wed behind the fropa, when afternoon highs only in the low 80s OBX zones to upper 80s inland with lowered RH's as well. Heating back up Thu into Fri as return swrly flow returns.
18z Monday through Saturday Mostly VFR flight cats expected this afternoon and through tonight outside of any storms. Ssw winds become gusty before relaxing some overnight. Gusts upwards of 20 kt by afternoon. May be a isolated shower or storm along the inland seabreeze this afternoon. Best chances for showers and storms still look like this evening, mainly at ISO and PGV. Rain threat ends ~6Z with prevailing VFR forecast. Light SWerly breeze should prohibit any fog development, but could come into play over NWern areas should winds decouple after low levels stabilize after rain.
Outlook (Tue through Fri): Front will sweep through Tue afternoon and evening, with another shot for sct afternoon showers and storms, esp along the eastern terminals. Some of these storms may be strong to severe and pose a threat for subVFR flight cats due to VIS. Winds turn nrly to nerly behind the front Tue evening with any precip threat ending. Mostly dry for Wed and Thu with high pres rebuilding. Next precip chance on Fri with another system approaching.
High pressure strengthens offshore along with inland trough combined with approaching cold front, have lead to SSW winds 15-20 kt with occasional gusts to 25 kt late this afternoon and evening. Some infrequent SCA criteria gusts are occuring where funneling of these Serly winds is strongest, mainly over Croatan and Roanoke Sounds. An MWS has been issued for these waters through sunset. Nocturnal showers and storms possible outside of 20nm tonight. 12z guidance coming in stronger with the low traveling along the front to work through ENC TUE has led to an increase in the wind forecast tomorrow and the issuance of SCAs across most of area waters for 15-25kt with gusts 30-35kt.
Outlook (Tue night through Fri): The front will move through the waters Tue night with flow becoming N-NE 5-15 kt behind it. Shower activity diminishes quickly behind the front, though some lighter showers wrapping around the departing low will be possible around midnight. Return swrly winds for Thu into Fri though looks to remain below SCA conditions.
Nc, none. Marine, small craft advisory from 11 am Tuesday to 1 am EDT Wednesday for amz135-152-154. Small craft advisory from 1 pm to 7 pm EDT Tuesday for amz137. Small craft advisory from noon Tuesday to 1 am EDT Wednesday for amz150. Small craft advisory from 11 am to 11 pm EDT Tuesday for amz156-158. Small craft advisory from noon Tuesday to midnight EDT Tuesday night for amz231.
