textproduct: Newport/Morehead City

WHAT HAS CHANGED

Have adjusted PoPs based off latest trends in guidance.

Have issued a Heat Advisory for the SW'rn zones for today.

Aviation forecast has been updated.

KEY MESSAGES

1) Oppressive heat and humidity continues today across ENC.

2) A more active pattern takes shape today and persists into midweek, with showers and storms expected each day, some of which could bring gusty winds and heavy rain.

3) Another round of dangerously high heat and humidity builds mid to late week into the weekend.

4) A very unstable atmosphere develops in tandem with the high heat and humidity mid to late in the week, and could produce a few strong to severe thunderstorms.

DISCUSSION

KEY MESSAGE 1...A warm and muggy morning today as temps generally remain around the 70s to low 80s across ENC as of this update. Don't expect temps to dip much more by daybreak as a weak warm front has lifted north of the area with just some isolated low and mid level cloud cover noted inland and some isolated showers and thunderstorms noted across our coastal waters.

As we get later into today, another warm and muggy day is expected with ridging aloft decaying across the region and a surface trough developing this afternoon across central NC. An inland moving seabreeze will also develop later this morning. Have blended in some Hi-Res and MOS guidance with the NBM temps today which has lowered MaxTs by a degree or two especially along the OBX and immediate coast. Shower and thunderstorm activity is forecast to develop later this morning and afternoon along the seabreeze and to the west along the aforementioned surface trough which should help to keep highs today slightly cooler than previous days. Given all of the above, have a temp gradient from W to E across the CWA with mid 90s noted across the western Coastal Plain which should see the most sun today and upper 80s noted along the coast and OBX where showers and thunderstorms start the earliest. With dewpoints in the 70s, this is forecast to bring heat indices around 100-105F across inland zones today with the highest heat indices noted across our SW'rn zones. As a result have issued a heat advisory across Duplin, inland Onslow, Lenoir, Jones, and Greene Counties as these areas look to remain precip free the longest and have the most confidence in heat indices reaching 105F here. The one spoiler to the heat advisory will be the potential for shower and thunderstorm activity to develop earlier in the day across these counties.

KEY MESSAGE 2...An active precip pattern finally sets up again today and persists into Wed as a series of shortwaves, inland troughing, and a very slow moving backdoor front will converge to produce higher than climo coverage of showers and storms each afternoon to early evening. Guidance continues to suggest PoPs remain around the 50-70% range each afternoon and evening. While PoP's will be higher than they have been the past several days, precip will certainly be very hit or miss across ENC, but much welcome none the less.

Will see PWATS jump to 2+ inches across ENC starting today with this very moist airmass remaining in place over the next few days. Combined with ample heating across ENC, instability will rapidly build each day with MLCAPE values generally expected to be between 2000-3000+ J/kg each afternoon. While instability will certainly be plentiful, deep layer shear will not be, as wind shear struggles to get above 25 kts. This will likely limit any significant storm organization over the next few days but cannot rule out some wet microbursts or stronger winds (40-60 mph) within the strongest storms along the aforementioned seabreeze and surface trough. Because of this, SPC has outlined a good portion of ENC in a Marginal Risk (1/5) of severe tstorms today and tomorrow. Another round of decent covg of afternoon showers/storms possible Wed as the aforementioned boundaries may still be in place. In addition to the severe threat today and tomorrow, there will also be a heavy rain threat with any thunderstorm that develops as well given the high PWAT's (2" +) which could lead to some localized flooding mainly in poor drainage and urban areas. As a result WPC also has much of the area under a marginal risk for excessive rainfall over the next two days as well.

Beyond mid week, PoPs return back to climo (20-40%) as more typical seabreeze showers/storms return. Hts/thicknesses slowly build in the process as ridging begins to build once again, with heat indices 100-105 in the forecast.

KEY MESSAGE 3...Aforementioned ridging builds mid to late week into the weekend, as ensemble mean heights rise back to above normal, and forecast temps reach well into the 90s, pushing heat indices to potentially at or above 105F again as a very humid atmosphere will be in place as well. EFI for both Min/MaxTs are pushing into the 80th percentile esp late in the week.

KEY MESSAGE 4...With the aforementioned high heat and humidity expected, a very unstable atmosphere develops per med range guidance hinting at ML CAPES aoa 3.5k J/KG, and SFC based instability between 4-5k J/KG. As is typical this time of year, deep layer shear will not be too strong, but any storms that can develop with some upper level support could produce strong downdraft/microburst winds and very heavy rain characterized by PW's exceeding 2".

AVIATION /10Z MONDAY THROUGH FRIDAY/

A mixed bag of ceilings and visibility across the Coastal Plain this morning as patchy fog and low stratus has overspread the area bringing a mix of MVFR to LIFR conditions. Currently as expected OAJ and adjacent areas are seeing LIFR vis with a mix of IFR/MVFR ceilings noted at ISO/EWN this morning. All fog and low stratus is forecast to burn off within the next hour or so resulting in widespread VFR across ENC later this morning.

Then as we get into the late morning and afternoon hours guidance continues to suggest scattered shower and thunderstorms develop along the seabreeze with activity starting closer to the coast first then spreading inland this afternoon. This activity will result in brief periods of sub-VFR ceilings/vis as storms move over TAF sites. Have handled this with TEMPO groups for all TAF sites with EWN/OAJ starting between 18-22Z and ISO/PGV between 19-23Z today. After sunset any leftover showers and storms will dissipate bringing VFR conditions back briefly. Another round of fog and low stratus will once again be possible later tonight as the area remains under a moist airmass.

Outlook (Tue through Fri): Shortwave energy tracking cross the region into midweek brings good chances for showers and thunderstorms and potential for sub-VFR conditions into Tue, possibly into Wed as well. Beyond mid week, more typical iso to widely sct activity expected as ridging rebuilds into ENC.

MARINE

Steady 10-15 kt SW'rly winds with gusts up around 15-20 kts is noted across our waters this morning while seas along the coastal waters remain around 2-4 ft. These conditions should continue to persist today as Bermuda high remains offshore and a front slowly begins to approach. As this front begins to get a little closer tonight winds especially across the Pamlico Sound and coastal waters south of Oregon inlet should increase slightly with gusts up to 25 kts possible across the aforementioned waters. As a result have kept the SCA's up across these waters starting around 10PM tonight and persisting into Tue morning. Seas will also build to about 3-5 ft during this timeframe with some 6 ft seas possible 20+ NM away from shore.

Outlook (Tue through Fri): The gradient relaxes Tue morning with winds returning to 5-15 kt. Weakening front moves into the waters on Wed, though as is typical in July, the front appears to wash out, with any N'rly flow behind it short lived with return flow developing as early as Wed evening. SW'rly winds look to strengthen some on Fri as a thermal trough strengthens across the area bringing our next potential threat for SCA's to the waters.

MHX WATCHES/WARNINGS/ADVISORIES

NC...Heat Advisory from noon today to 8 PM EDT this evening for NCZ079-090>092-198. MARINE...Small Craft Advisory from 10 PM this evening to 8 AM EDT Tuesday for AMZ135-156-158. Small Craft Advisory from midnight tonight to 8 AM EDT Tuesday for AMZ152-154.