textproduct: Newport/Morehead City

WHAT HAS CHANGED

Adjusted PoP forecast based off recent trends in guidance and radar.

KEY MESSAGES

1) A few rounds of severe weather remain possible this weekend. There is a Slight risk (2/5) of severe weather this afternoon and evening, and a Marginal (1/5) risk on Sunday.

2) Expecting hot and humid conditions once again on Sunday with highs in the 90s, and heat indices around 100-105 Sun.

3) Dangerous heat likely mid to late next week heading into the holiday weekend.

DISCUSSION

KEY MESSAGE 1...The morning convection and cloudcover has thrown in a little bit of a wrench into the forecast for this afternoon and evening, with mesoscale features likely driving much of the precipitation forecast today and tomorrow.

The shortwave that had brought shower and thunderstorm activity to areas east of Hwy 17 this morning has since pushed offshore. Behind this shortwave, cloud cover has lifted with any leftover low stratus now becoming diurnal Cu. This has resulted in some differential heating boundaries across the CWA with areas away from the OBX seeing quicker rises in temps and thus resulting in widely scattered showers and thunderstorms mainly along the Crystal Coast this morning and early afternoon. As we go further into the afternoon, these differential heating boundaries will be the focus for additional isolated to widely scattered showers and storms inland. Will note, latest guidance has come in drier with this activity likely owing to some subsidence aloft from the departing shortwave. However, given the unstable and moist airmass will not rule out early to mid afternoon activity out ahead of the main show later tonight so kept PoPs fairly consistent within the 30-50% range. We are also monitoring an approaching MCV from the west which is forecast to jump start thunderstorm development across central VA/NC this afternoon and evening as well. This activity is forecast to push into the CWA later today and tonight and may not depart the OBX until after midnight.

As stated above, a moist and unstable airmass will remain in place across ENC today with dewpoints in the upper 60s to low 70s and temps in the 90s. This is forecast to allow for ample instability to build with MLCAPE values generally ranging from 1500-2500+ J/kg this afternoon across much of ENC with lowest values likely across the OBX where morning convection has kept cloudcover the longest. Shear generally looks to remain around 20-25 kts across ENC this afternoon. While this isn't very strong and likely inhibits significant storm organization initially, given the instability and enough forcing from the aforementioned boundaries, isolated to widely scattered showers and thunderstorms remain possible this afternoon with a few becoming strong to severe in nature. Given ample moisture will also be in place across ENC damaging winds in the form of wet microbursts (40-60 mph wind gusts) would be the primary concern with the afternoon activity.

Yet another round of convection is forecast this evening into tonight coming in from the north and west as an MCV/incoming shortwave kicks off convection around the Triad region today. This activity starts out initially as scattered showers and thunderstorms to our north and west. As it approaches ENC, expect thunderstorms to merge into clusters and potentially a MCS, impacting the area mainly after 5/6PM and persisting until potentially after midnight. MLCAPES still look to be above 1000 J/kg tonight and while ambient shear values likely remain around 20-25 kts, if the MCS can get organized enough, it may produce some locally higher deep layer shear values closer to 30-35 kts. As these thunderstorms clusters/MCS moves through the area the primary threat would once again be damaging winds (40-60 mph). Given all of this we remain in a Slight risk (level 2/5) for most of the CWA given the potential wind impact from thunderstorms today.

On top of all of this, WPC has the area under a marginal risk for excessive rainfall as showers and thunderstorms will be able to take advantage of the high PWAT environment (PWATS AROUND 2"). With soundings showing atmospheric columns having ample CAPE, moisture through the column, and deep warm cloud layers any shower or storm would have to potential to produce 1-2" an hour rainfall rates which could easily overwhelm drainage area especially considering the ongoing drought. This could result in some localized areas of flooding especially near more urban areas.

On Sunday yet another shortwave looks to impact the area ahead of an incoming backdoor cold front. CAMs suggest a MCS moving into the region along the shortwave in the evening in addition to any sea breeze convection developing in the afternoon. With better upper level support and more favorable timing compared to todays MCS, this one has a shot at bringing some damaging winds as well. The back door cold front looks to move through overnight Sunday. Precip with the shortwave out ahead of it will likely stabilize up a bit, bringing a lower thunderstorm risk along the front. SPC has us in a marginal (1/5) risk of severe weather Sunday.

KEY MESSAGE 2...A WAA regime will persist through this weekend as high pressure becomes centered offshore. This will bring continued SSW winds and increasing low level thicknesses to ENC. Latest guidance continues to show low level thicknesses generally around 1410-1425m which support highs into the low to mid 90s each day. With temps in the low to mid 90s and dewpoints in the upper 60s to low 70s heat indices will likely peak around 95-103 today and Sunday. Will note, given cloudcover and precip chances both today and tomorrow it looks like we may remain lower than heat advisory criteria so currently not anticipating any heat headlines this weekend. Sunday will see another day of near heat advisory criteria AppTs, 100-105F thanks to the slower progression of the back door cold front. With lows only getting into the 70s each night this weekend there wont be much relief from the heat. If you have any extended plans outdoors this weekend make sure to stay properly hydrated and take proper precautions when outside.

KEY MESSAGE 3...No significant changes to the extended forecast as an omega block sets up across the Eastern CONUS with anomalous ridging persisting across the the midwest and eastern US next week. This will bring the potential for an extended period of dangerous heat to ENC starting around Thurs next week and continuing into the July 4th weekend. NWS probabilistic Heat Risk values of reaching major heat risk levels or higher are currently sitting at about 30-50% on Wed, 60-80% on Thurs, and 80-90% on Fri/Sat which is fairly notable given the higher end values this far out. Those sensitive to heat and anyone planning on spending ample amounts of time outside later next week should continue to monitor the forecast trends as this potential heat wave would have impacts on the holiday weekend.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

VFR conditions across the terminals early this afternoon, as showers continue to blossom east of Hwy 17. Still a very tough precip forecast over the next 24 hrs. Best chance through 00z will be at EWN and OAJ, then after 00z best chances shift towards PGV and ISO as weakening MCS approaches the coastal plain. A few stronger storms may develop with the potential for 40-60 kt wind gusts. Winds may decouple inland overnight, which could lead to patchy fog and low stratus after 9z, with best chances at PGV and ISO. VFR likely to return after 15z with potential for more scattered showers and storms Sunday afternoon and eve ahead of an approaching front.

Outlook (Sun night through Thu): Showers and storms could be ongoing in the evening, with periods of sub-VFR. The front will move through Sun night, with conditions improving as N-NE develops. Patchy fog and low stratus will be possible each morning.

MARINE

Ongoing 15-20 kt SW'rly winds with gusts up to 25 kts are noted across the coastal waters between Cape Lookout and Oregon Inlet and across the Pamlico Sound which is where ongoing small craft advisories are currently noted. Elsewhere 10-15 kt SW winds with gusts up to 20 kts are noted. These winds are forecast to continue into tonight before easing as the area will be between mid level shortwaves and well out ahead of an approaching cold front. This should end the last of the SCA's across our waters by about 5AM Sun morning. Afterwards do expect winds to ease further on Sun, lowering to 5-15 kts Sun morning and then shifting to a NE direction from north to south behind the front Sun night. Seas during this timeframe generally remain around 3-5 ft outside of some Gulf stream waters where 4-6 ft seas aren't out of the question especially today with the elevated SW'rlys.

Once again will mention the potential for scattered showers and strong thunderstorms into tonight and once again on Sunday. Already have ongoing activity across the inland waters which should make its way to the coastal waters tonight before a brief receive Sun morning followed by yet another round of storms Sun afternoon. Any storm that develops would bring a threat for locally enhanced winds and seas.

Outlook (Sun night through Wed): Gulf stream showers and thunderstorms possible through Sun evening with the shortwave and back door cold front. Winds will eventually shift from the SW to the NE on Sun night and Mon from N to S behind the aforementioned front. NE winds then persist behind the cold front Tue into midweek.

MHX WATCHES/WARNINGS/ADVISORIES

NC...Beach Hazards Statement until 8 PM EDT this evening for NCZ195- 196-199-204-205. MARINE...Small Craft Advisory until 11 PM EDT this evening for AMZ135. Small Craft Advisory until 11 PM EDT this evening for AMZ152. Small Craft Advisory until 5 AM EDT Sunday for AMZ154-156.