textproduct: Raleigh

WHAT HAS CHANGED

As of 200 AM Sunday...

* No major changes.

KEY MESSAGES

As of 200 AM Sunday...

1) Record highs likely today with an airmass typical of late June to early July

2) The combination of unseasonably warm temperatures, low humidity, dry fuels, and breezy conditions behind a cold front favor an elevated fire danger risk on Monday.

3) A strong cold front could move across the region Fri-Sat, specifics are uncertain.

DISCUSSION

As of 200 AM Sunday...

KEY MESSAGE 1... Record highs likely today with an airmass typical of late June to early July

Record hot temperatures are expected today ahead of a cold front slated to move through on Monday. At the surface, southwest flow will be in full swing this afternoon with high pressure stretching from the Gulf into the western Atlantic. The low-level airmass is typical of what we see in late June or early July over central NC, supportive of mid to upper 80s for most places. Even a few spots touching 90 degrees over the Triangle and Sandhills is not out of the realm of possibilities. The NBM shows a 20-40 percent chance of 90 or greater in these areas. Our forecast highs will likely tie or break the record high values at all of our climate sites. Very warm temperatures are forecast to persist tonight, with lows some 20-25 degrees above normal in the 60s.

KEY MESSAGE 2... The combination of unseasonably warm temperatures, low humidity, dry fuels, and breezy conditions behind a cold front favor an elevated fire danger risk on Monday.

A moisture-starved cold front will move through central NC in the late morning and early afternoon on Monday, with slight chance to low-end chance of showers and storms, mainly in the east and southeast. High temperatures should reach the low-mid-70s north to low-mid 80s south. Dew points will crash behind the front, dropping into the upper 20s NW to mid-upper 40s SE by 00Z Tue, with RH values of to 25-35% across the Piedmont by mid afternoon. Post-frontal gustiness could also reach 20-25 mph according to GFS and NAM forecast soundings. While winds look too low for Red Flag Warning criteria, these factors combined with dry fuels could still result in an increased fire danger risk in the west on Monday from mid afternoon to early evening. The SPC outlook for Mon continues to highlight that area in a 40% likelihood for critical conditions. Some will depend on the frontal orientation, as most guidance seems to suggest post-frontal winds having more of a northerly vs westerly component, which would somewhat limit downsloping potential. While an IFD may eventually be needed, for now continue to highlight in our HWO.

KEY MESSAGE 3... A strong cold front could move across the region Fri-Sat, specifics are uncertain.

Aloft, the longwave trough will amplify (though the degree varies between the medium-range guidance) and help suppress the ridge southward as a couple of shortwaves move across the Great Lakes/OH Valley from Thu-Sat. At the surface, a lee trough will develop Thu/Thu night, and remain in place until the cold front, approaching from the NW, moves into the area Fri/Fri night. Despite fropa timing differences, operational runs of both the EC an GFS have a surface low over the Carolinas as the front moves through. Canadian high pressure will build into the region in the wake of the front over the weekend. Showers will be possible with the fropa. There will be a significant temperature change with the front, swinging from well above normal Thu night/Fri, to near normal Fri night-Sat.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

As of 600 AM Sunday...

An area of showers has developed across the Triad terminals early this morning in association with a northward moving warm front and moist advection. Most of these showers will dissipate after sunrise, but cannot rule out a brief shower prior to 13z at GSO, INT, and RDU. Confidence is too low to include a shower chance at FAY, but it cannot be ruled out into mid-morning prior to the warm frontal passage. As the warm front lifts north, weak south to southwest winds will increase out of the southwest during the afternoon as a lee trough develops. Surface gusts between 18-24 kt will be favored until 22-23z, after which sustained winds from the south-southwest will hover in the 8-11 kt range. A 40-45 kt LLJ will develop tonight between 06z-12z Mon and favor a period of LLWS at RDU, FAY, RWI. This may end up being mechanical turbulence, but opted for LLWS given expected decoupling of surface winds.

Outlook: A strong cold front will bring a chance of a few showers or storms Mon aftn/eve, most favored at FAY/RWI. Gusty winds of 20-30 kt will be possible at all sites Mon through Mon night.

CLIMATE

Record High Temperatures:

March 22: KGSO: 85/1948 KRDU: 89/1907 KFAY: 88/1948

March 23: KFAY: 86/1948

March 27: KFAY: 87/1946

Record High Minimum Temperatures:

March 22: KGSO: 63/1948 KFAY: 63/1948

March 23: KFAY: 64/1952

March 27: KGSO: 60/2007 KFAY: 65/1949

RAH WATCHES/WARNINGS/ADVISORIES

None.