textproduct: Raleigh

WHAT HAS CHANGED

As of 125 AM Wednesday...

* No major changes to the forecast.

KEY MESSAGES

As of 125 AM Wednesday...

1) Patchy frost remains possible for portions of central North Carolina late tonight into Thursday morning.

2) Fire weather concerns will remain elevated through this weekend owing to dry conditions, low relative humidity and no rainfall forecast in the next 7 days.

DISCUSSION

As of 125 AM Wednesday...

KEY MESSAGE 1... Patchy frost remains possible for portions of central North Carolina late tonight into Thursday morning.

The anomalous ~1040mb surface high is expected to shift eastward off the New England coast by tonight, allowing the ridge axis to settle more over the Carolinas. Unlike earlier in the week, this positioning will favor a more optimal radiational cooling environment as the pressure gradient relaxes, potentially allowing surface winds to fully decouple and become nearly calm across most of Central NC overnight. While low-level thicknesses are expected to rise, the lack of wind will allow surface temperatures to drop quickly, with lows ranging from the low-to-mid 30s across the northern Piedmont and Coastal Plain to the upper 30s south of the Triangle. Adding to the frost potential is a gradual increase in low- level moisture. Dewpoints are expected to climb from the 20s into the mid-30s overnight from east to west, providing the necessary moisture for ice crystal development on vegetation, especially across the Piedmont. The primary forecast uncertainty for Thursday morning remains the coverage and thickness of the high clouds. While the potential for high cirrus could act as a light blanket and limit cooling, any clearing would likely result in widespread patchy frost. Given these conditions, a Frost Advisory may be necessary for northern and western portions of the CWA.

KEY MESSAGE 2... Fire weather concerns will remain elevated through this weekend owing to dry conditions, low relative humidity and no rainfall forecast in the next 7 days.

Dry westerly flow will persist across the region between a broad upper trough over the northern US and strengthening ridge over the gulf, limiting moisture return and resulting in a dry forecast through early next week. The aforementioned ridge will build across the southern US, yielding a strong low-level anti-cyclone over the Southeast and a favorable pattern for well-above-normal temperatures by Saturday when forecast highs reach the mid 80s. These warm and dry conditions, with daily afternoon RH is in the 20 percent range will not help recent fire concerns and the statewide burn ban, mitigated only by relatively weak winds each day under high pressure. Winds will gradually become southwesterly and a little stronger by early next week, but there will also better moisture return and higher RH.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

As of 620 AM Wednesday...

High confidence VFR conditions will continue across all of central NC. The primary aviation concern is brisk northeasterly flow as a dry air mass remains in place. Expect clear skies or thin high cirrus and no restricted visibilities for the 24 hour TAF period.

Surface winds will remain around 10kts through the morning, then increasing and becoming gusty mid morning as daytime mixing deepens. Expect NE winds of 10-15kts with gusts up to 20kts, especially in the afternoon hours. The strongest gusts are expected mainly at KFAY and KRWI. Gusts will subside around sunset, with winds diminishing into a more light easterly flow overnight.

Outlook: Dry weather and VFR conditions are expected to persist through the upcoming weekend.

RAH WATCHES/WARNINGS/ADVISORIES

None.