textproduct: Raleigh

WHAT HAS CHANGED

As of 135 AM Thursday...

* There is the potential for fog early Fri morning.

KEY MESSAGES

As of 135 AM Thursday...

1) Frost Advisory remains in effect until 9 AM this morning. Patchy frost is possible again Fri morning over the northern Coastal Plain, where areas of fog may also develop

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

3) Near record warm temperatures expected Tue/Wed.

DISCUSSION

As of 135 AM Thursday...

KEY MESSAGE 1... Frost Advisory remains in effect until 9 AM this morning. Patchy frost is possible again Fri morning over the northern Coastal Plain, where areas of fog may also develop

The Frost Advisory remains in effect for the Piedmont, western Sandhills, and portions of the northern Coastal Plain until 9 am this morning. Temperatures over these areas are expected to hover in the low to middle 30s by daybreak, promoting potential frost formation. Currently, areas of stratus and light stirring has kept most central NC in the 40s. But these high clouds should become less widespread into early this morning, allowing good radiational cooling by sunrise.

For tonight into early Fri, guidance, specifically the HRRR, HREF, and RAP, is starting to pick up on the potential for fog over the northeast Piedmont and northern Coastal Plain. The setup features overall clear skies compared to the past few days, calm winds, and rising dewpoints into the low 40s. These conditions will promote radiation fog via more favorable crossover temperatures. In addition, we cannot rule out some patchy frost over the typical cooler spots of the Piedmont (Siler City, Roxboro) and northern Coastal Plain. Another Frost Advisory may be needed for a portion of the area tonight into early Fri as a result.

KEY MESSAGE 2... Fire weather concerns will remain elevated through early next week 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 at least the middle of next week. A weak cold will try to slip south through the Mid-Atlantic states on Saturday but will will most likely not make it into central NC as the aforementioned ridge will build across the southern US. 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. A cold front is forecast to move into the central US by the middle of next week, which will cause winds will gradually become southwesterly and a little stronger. However, there will also better moisture return and higher RH to potentially offset any potential fire weather issues.

KEY MESSAGE 3... Near record warm temperatures expected Tue/Wed.

Low-level thicknesses are forecast to exceed 1400m by the middle of next week, some 40-45m above normal. This would result in highs as much as 15-20 degrees above normal, approaching record levels Mon/Tue. This level of early-season heat could be dangerous, especially to those vulnerable to heat.

AVIATION /06Z THURSDAY THROUGH MONDAY/

As of 1252 AM Thursday...

There is high confidence in VFR conditions through the 24-hour TAF period. We cannot rule out a brief MVFR ceiling at RWI early this morning with some low stratus moving onshore around the surface high, but confidence is too low to include at this time. Winds will remain out of the ENE at 5-8 kt through the period.

Outlook: Guidance is indicating the potential for radiation fog Fri morning, most favored at RWI and possibly RDU. Otherwise, VFR should prevail through early next week.

CLIMATE

Record High Temperatures: April 11: KFAY: 90/2001 April 13: KGSO: 88/1930 KRDU: 89/1922 April 14: KGSO: 90/1922 KRDU: 91/1941 KFAY: 93/1922 April 15: KGSO: 90/2006 KRDU: 92/1941 KFAY: 95/2006

Record High Minimum Temperatures: April 13: KGSO: 61/2019 KRDU: 66/1930 April 15: KGSO: 65/2006 KRDU: 64/1993

RAH WATCHES/WARNINGS/ADVISORIES

Frost Advisory from 2 AM to 9 AM EDT Thursday for NCZ007>011- 021>027-038>041-073>076-083-084.