textproduct: Raleigh

WHAT HAS CHANGED

* No significant changes from earlier forecasts.

KEY MESSAGES

As of 100 AM Thursday...

1) Continued above normal temperatures through Saturday.

2) Measurable precipitation chances and frequency of events increase starting this weekend through the end of April.

DISCUSSION

As of 100 AM Thursday...

KEY MESSAGE 1... Continued above normal temperatures through Saturday.

The combination of surface high pressure centered NE of the Bahamas extending over the Southeast coast and an 850 mb anticyclone centered near SAV will continue to bring above-normal low level thicknesses to the Carolinas through Sat, with values up to 25-30 m above normal. We'll maintain a weak NW steering flow aloft, and with a lack of moisture influx through the low and mid levels, any clouds will be largely limited to sct to briefly bkn high-base cu each afternoon today and Fri. This high insolation with elevated thicknesses favors highs around 10-15 degrees above normal, in the mid 80s to around 90. Our Heat Risk is forecast to be a Level 1-of- 4/Minor once again today, suggesting heat that will mainly affect those extremely sensitive to heat. But by Fri, with a third straight day of atypical early-season heat, our Heat Risk rises to a Level 2- of-4/Moderate for portions of central NC, including from the Triangle area and N Sandhills into the Coastal Plain, indicating that this heat may begin to affect anyone without cooling or hydration. Those who must work or exert in direct sunshine at the hottest part of the day should be extra cautious, stay well hydrated, and take cooling breaks in the shade.

KEY MESSAGE 2... Measurable precipitation chances and frequency of events increase starting this weekend through the end of April.

Guidance continues to suggest two main chances for measurable rainfall through the forecast period; late Saturday into Sunday and Tuesday.

Late Saturday into Sunday: A convectively modified shortwave ejecting over the Ohio Valley Sat afternoon is expected to shift across the Mid-Atlantic Saturday evening into Sunday morning. This feature, along with eastward advection of seasonably anomalous deep- layer moisture, will help direct convectively perturbed westerly flow over the region. Forcing for ascent will be localized along the track of MCV's from upstream convection. This will lead to locally enhanced convection with widespread rain not expected. Expect primarily light QPF, with mostly 0.25 or less. However, 0.5 to 1 inch local totals will be possible, especially north.

Tuesday: A more significant trough is forecast to pivot from the Four Corners Region to the Great Lakes from Sunday to early Tuesday around the parent closed-low over Saskatchewan/Manitoba. Once again, our region will likely see a glancing influence from the trough and mainly directs another plume of seasonably anomalous deep-layer moisture and perturbed westerly flow. Some light stratiform rain may fall over portions of the region Tuesday morning. Then, Tuesday afternoon and evening increased low level moisture and warm boundary layer temperatures may support scattered afternoon/evening showers and thunderstorms.

AVIATION /06Z THURSDAY THROUGH MONDAY/

As of 105 AM Thursday...

VFR conditions are likely to persist over the next 24 hours, with high confidence. Sct-bkn mid level clouds currently drifting SSE over the area will continue to break up as the disturbance aloft which generated these clouds (and a few weak radar returns as well) weakens and pushes to our SE. Sct mid level clouds are possible this upcoming afternoon, but otherwise skies will remain fair to clear. Surface winds will be light and variable except 8-12 kts from the WNW (gradually shifting to W and WSW) 14z-23z.

Looking beyond 06z Fri, VFR conditions should dominate through Sat morning. The chance for sub-VFR conditions will increase as showers and a few storms sweep through the area from late Sat afternoon through Sun morning. Another round of showers and storms with possible sub-VFR conditions will occur late Mon night through Tue evening.

RAH WATCHES/WARNINGS/ADVISORIES

None.