textproduct: Newport/Morehead City

WHAT HAS CHANGED

No significant changes.

KEY MESSAGES

1) Hot through Friday, with increasing humidity

2) More unsettled pattern expected Friday through the weekend as front stalls near the area.

3) Back to a more typical summertime pattern next week with high draped over the southeast.

DISCUSSION

KEY MESSAGE 1...Notably warm low-level thicknesses beneath anomalous ridging aloft will support above to well above normal temperatures for much of ENC through Friday. The one exception is the northern OBX where a slowing front may briefly dip into the area leading to a "cooler" northeasterly flow. In that area, I went below blended guidance to reflect highs not getting quite as warm as the rest of ENC where southerly flow will persist.

Increasing low-level moisture will support increasing humidity on Friday, which should translate to heat indices topping out at 100- 105 degrees. A Heat Advisory was considered, but the risk area appears too small to warrant any headlines for now.

KEY MESSAGE 2...On Friday, a slowing cold front will begin encroaching on ENC from Virginia. Guidance is mixed regarding how far south this front gets before stalling. Given the strength of the Southeast U.S. ridge, it would make sense that the front won't make much headway through ENC. Meanwhile, moisture and instability will continue to increase south of the front, and this should support at least a slight step up in the risk of afternoon convection compared to today. This may especially be the case as a shortwave moves through the area and as we get a glancing influence from the entrance region of an upper jet that will be sliding by to the north. While the focus of convection should be where the front stalls, it stands to reason that isolated to scattered convection will be able to develop, likely focused along the seabreeze. Instability looks to be modest (around 1000j/kg MLCAPE), but with some residually dry air aloft and higher DCAPE, the strongest storms may produce gusty winds of 40-50 mph.

Moisture continues to build on Saturday, with PWATs forecast to rise above 2". This combined with the seabreeze, a dampening shortwave, and inland troughing should support an increased coverage of convection compared to Friday. There's some uncertainty regarding the strength of convergence along the inland trough. If the inland trough ends up weaker, the coverage of convection may be lower across the coastal plain. Regardless, any thunderstorms that form on Saturday will be capable of very heavy rainfall rates and minor, nuisance-stlye flooding. Instability continues to look modest, and this should keep the risk of strong to severe thunderstorms LOW.

On Sunday, the stalled front should finally get shoved south through all of ENC as a stronger shortwave passes by to the north. A continued moist and modestly unstable environment should support another day of scattered to perhaps numerous showers and thunderstorms along the advancing front. Heavy rain and minor flooding continues to look like the primary risk.

KEY MESSAGE 3...Anomalous upper level ridging and a notably strong surface high builds into the Mid-Atlantic and Carolinas next week favoring warm and dry conditions.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Forecast confidence is moderate over the next 24 hours.

Subsidence and dry air aloft is expected to keep the risk of TSRA low through Friday morning, and conditions should primarily be VFR. The one exception, though, is late tonight into early Friday morning when a mix of low stratus and shallow fog may develop. Ensemble guidance shows moderate probabilities (40-60% chance) of sub-VFR CIGs developing. This seems reasonable given low-level moisture returning north into the area. Sometimes guidance can be too quick to develop low CIGs in this setup. In light of all of the above, I have introduced a SCT015 layer from 09z-15z to highlight when this risk may develop.

Outlook: Increasing moisture and instability is expected to lead to an increasing risk of TSRA later Friday afternoon through Sunday. A risk of sub-VFR conditions will accompany the TSRA risk as well. Periods of low stratus/CIGs will be possible Friday night and Saturday night as well. A cold front is forecast to move south through the area on Sunday with a northerly wind shift and drying conditions behind it. VFR conditions then look to prevail early next week.

MARINE

A tightened pressure gradient has led to southwesterly winds of 15- 20kt across area waters this afternoon. Most waters should stay below 25kt for gusts, and no marine headlines are anticipated at this time. However, the Pamlico Sound and nearby waters should see occasional gusts to 25kt through late this evening. Winds are forecast to lay down some late tonight into Friday as a front approaches from the north with a somewhat relaxed gradient. It will still be breezy, though, especially for the southern waters where the gradient will be the strongest.

The risk of thunderstorms may increase across the southern waters late tonight into early Friday morning as a weakening coastal low approaches from the south. The risk of thunderstorms then shifts to the inland rivers and sounds, especially the Alligator/Albemarle/Croatan/Roanoke waters.

Outlook: A cold front is forecast to be stalled around the Albemarle Sound vicinity Saturday morning. This front will then lift north of all waters during the day Saturday. The front will then come back south through the area on Sunday. Thunderstorms on Saturday should be focused across the inland rivers and sounds. The risk then shifts south and to the coastal waters on Sunday as the cold front moves through. A period of northerly flow ensues behind the front and then lasts into next week.

MHX WATCHES/WARNINGS/ADVISORIES

NC...None. MARINE...None.