textproduct: Raleigh

WHAT HAS CHANGED

As of 215 PM Sunday...

No major changes.

KEY MESSAGES

As of 215 PM Sunday...

1) Backdoor cold front arrives this evening with isolated showers possible across the Piedmont and Coastal Plain.

2) Predominantly cold rain Monday afternoon through Tuesday morning, but a brief period of sleet mixing with rain remains possible north of I-85 corridor and northern Coastal Plain.

3) Well-above normal temperatures and near record breaking warmth expected late week into the weekend.

4) Slight chance for isolated showers and storms Friday and again on Sunday.

DISCUSSION

As of 215 PM Sunday...

KEY MESSAGE 1...Backdoor cold front arrives this evening with isolated showers possible across the Piedmont and Coastal Plain.

Warm sswly flow ahead of an approaching backdoor cold front has shot temps up this afternoon into the mid 70s. Expect a few more degrees to squeeze out the next few hours, with highs in the mid to upper 70s area-wide. Further upstream, the backdoor cold front is quickly pushing across the Chesapeake Bay. This front is still expected to cruise through central NC early this evening/early tonight. Weak sfc forcing along this boundary, coupled with a few hundred J/kg of SBCAPE, may induce a few isolated showers mainly across the central Piedmont into the Coastal Plain vicinity. A few cracks of thunder are possible, but not sure how deep these cells will get given weak instability/forcing. Any lingering showers should scoot east of our area by ~03Z or so. Otherwise, expect nnely gustiness of up to 25 to 30 mph at times immediately following frontal passage and lingering some into the overnight period. Overcast conditions will build later tonight, with overnight lows in the upper 30s to lower 40s expected.

KEY MESSAGE 2...Predominantly cold rain Monday afternoon through Tuesday morning, but a brief period of sleet mixing with rain remains possible north of I-85 corridor and northern Coastal Plain.

Confidence continues to increase in mostly a cold rain within an initially classic-CAD regime Mon into Tues morning. Strong, but progressive, surface high pressure will shift across the Great Lakes tonight and be briefly in a favorable position over NY/PA by Mon morning. This surface high will quickly shift east through the day, but a sharpening inverted trough along the Carolina coast will persist north/northeasterly winds through Tues morning. The true Arctic air mass (with single digit dew points) will remain confined to the Northeast while a modified cooler but less dry air mass will work its way into central NC ahead of the arrival of precipitation.

Using top-down and nomogram techniques for expected p-type, the overwhelming model consensus is that the 850-700mb layer is expected to remain > 155dam over NC and likely will not support anything other than sleet, freezing rain, or cold rain. Since NC will be on the southern edge of any wintry p-type, small changes with the strength of the warm nose and position of the surface wet-bulb zero will make minor changes to the sensible, mostly conversational, p- type for the northern tier of continues. Expect predominantly a cold rain as precipitation spreads into the area through the morning hours with temperatures in the 30s to near 40 (temps may warm until into the mid/upper 40s towards the SC/NC border). Some conversational, rate-driven, sleet may mix in with the rain at the onset of precipitation. Given a very warm ground (air temps in the 60s to 70s the prior two days) and surface temperatures expected to remain above freezing, no accumulation is expected. Very light cold rain and drizzle will likely continue through the night into Tues morning within the CAD regime locked in over the area.

KEY MESSAGE 3...Well-above normal temperatures and near record breaking warmth expected late week into the weekend.

As surface high pressure shifts offshore Wednesday, weak upper-level ridging will maintain warm southerly flow across the region. High temperatures Wednesday and Thursday will reach the mid to upper 70s, with dew points generally in the 50s. By Friday, temperatures and dew points will increase ahead of a frontal boundary stretching across the Mississippi Valley. Highs are expected to run 1525 degrees above normal Friday and 1520 degrees above normal Saturday, with highs nearing record values. Over the weekend forecast highs in the upper 70s to lower 80s will be accompanied by dew points in the low to mid 60s.

As the front passes through the region Sunday, temperatures will trend slightly cooler but remain well above normal, with highs ranging from the mid to upper 70s which will be around 1020 degrees above normal.

KEY MESSAGE 4...Slight chance for isolated showers and storms Friday and again on Sunday.

As low pressure tracks from the Ohio Valley into the Northeast Thursday into Friday, increasing southerly flow and moisture return from the coast may support isolated showers and thunderstorms Friday afternoon, particularly with enhanced daytime heating. The next precipitation chance arrives Sunday as a frontal boundary approaches the Mid-Atlantic. Ensemble guidance suggests a low to moderate chance of measurable precipitation across central NC, with considerable spread in timing and coverage tied to frontal passage. Most members favor isolated to scattered showers, with higher PoPs possible across the northern and western Piedmont if the boundary slows along the Appalachians. For now, the highest PoPs are focused Sunday afternoon as the front attempts to move through the region.

AVIATION /06Z MONDAY THROUGH FRIDAY/

As of 140 AM Monday...

Nely surface winds will continue to gust into the upr teens to mid 20s kts at times this morning, behind a backdoor cold front that moved swwd across cntl NC Sun evening. Otherwise, initially VFR conditions will yield to MVFR ones in ceilings later today, as lift occurs across the front and atop high pressure that will ridge across the region. A little light rain will also be possible at Piedmont sites and RWI, and especially points nwd into VA.

Outlook: Continued nely flow will favor the development or lowering of ceilings into IFR range tonight-Tue morning, with only a slow transition through MVFR over the Piedmont through the day Tue and a quicker lifting and scattering to VFR at FAY and RWI. Stratus and/or fog will then be favored at ern sites (ie. FAY and RWI) Wed and Thu morning.

CLIMATE

Record High Temperatures:

March 5: KGSO: 81/1967 KRDU: 83/1967

March 6: KGSO: 78/2022 KRDU: 82/1967 KFAY: 86/1918

March 7: KGSO: 81/1974 KRDU: 85/1974 KFAY: 84/1961

Record High Minimum Temperatures:

March 6: KGSO: 64/1967 KRDU: 64/1967 KFAY: 65/1961

March 7: KGSO: 63/1956 KRDU: 64/1956 KFAY: 65/1961

RAH WATCHES/WARNINGS/ADVISORIES