textproduct: Raleigh

WHAT HAS CHANGED

As of 100 PM Wednesday...

* No major changes to the forecast.

KEY MESSAGES

As of 145 PM Wednesday...

1) Areas of fog will be possible Thu and Fri morning in an increasingly warm and moist pattern.

2) Very warm to near record breaking temperatures will prevail from Thursday through at least the middle of next week, with highs around 15-20 degrees above normal and lows around 20-25 degrees above normal. While at least isolated showers can't be ruled out each day, the best chance of showers and storms comes on Sunday/Monday and again on Wednesday.

DISCUSSION

As of 145 PM Wednesday...

KEY MESSAGE 1... Areas of fog will be possible Thu and Fri morning in an increasingly warm and moist pattern.

An anomalously warm pattern will be taking over the rest of today and especially Thu and the upcoming weekend as Bermuda high pressure brings in a warm and moist south-southwesterly flow. Temperatures this afternoon should reach the low to middle 70s for most of central NC, with perhaps even some upper 70s in the far south. By tomorrow, most of the area will be near 20 degrees above seasonal averages with upper 70s to some places touching 80. The low temperatures the next few nights will similarly be quite warm, over 20 degrees above normal in the mid to upper 50s to near 60. In the warm and moist regime, fog will be possible over the southern Piedmont, Sandhills, and Coastal Plain both Thu and Fri morning. The fog tonight into early Thu appears to be the higher chance. The HREF and its member, the HRRR, suggest the main area would be along the I- 95 corridor of the eastern Sandhills to the central Coastal Plain. However, some guidance depicts patchy fog as far north as the southern portions of the Triangle. Any fog should disperse by mid- morning in the warm southwest flow.

KEY MESSAGE 2... Very warm to near record breaking temperatures will prevail from Thursday through at least the middle of next week, with highs around 15-20 degrees above normal and lows around 20-25 degrees above normal. While at least isolated showers can't be ruled out each day, the best chance of showers and storms comes on Sunday/Monday and again on Wednesday.

Mid-level ridging atop a surface high centered near Bermuda will extend from the western Atlantic into the Southeast US from Thursday through Saturday, as deep troughing sets up over the Western US. There could be enough moisture and upslope flow on the periphery of the ridge to produce some showers over the Foothills that trickle into our western Piedmont on Friday and Saturday. Otherwise it will just be very warm, with highs in the upper-70s to lower-80s and lows in the upper-50s to lower-60s each day. Enough low-level moisture will be in place that areas of fog are possible each morning, with the best chance in the SE.

Meanwhile a piece of shortwave energy from the Western US trough will lift NE into the Northern Plains into Upper Great Lakes on Friday and Saturday, while a closed mid/upper low develops over the Desert Southwest and NW Mexico. The shortwave over the Upper Great Lakes will merge with a northern stream trough over south-central Canada, and this broad trough will act to suppress the western Atlantic ridge on Sunday and Monday. An associated cold front will approach our region on Sunday and Monday, though it looks to stall to our north before washing out. Still, increased moisture and instability ahead of the front combined with the suppressed ridge will result in greater coverage of showers both days, with isolated storms also possible. Precipitation amounts don't look too impressive, as WPC and ensemble mean QPF are generally a tenth to a quarter inch on average both days, but locally higher amounts will be possible. High temperatures on Sunday and Monday look a few degrees cooler on average with the increased clouds and precipitation, but they will still be well above normal.

The closed mid/upper low over NW Mexico will move east into the Southern Plains on Tuesday and Wednesday, as another northern stream trough moves across the northern tier of the US. While there are model differences in timing and the degree of phasing between the two systems, it looks like they will act to pump up the western Atlantic ridge and increase temperatures a bit further on Tuesday, with POPs dropping back near climo (slight to low chance). A cold front approaching from the west on Wednesday may help increase shower/storm chances again, but this will depend on the timing of the front.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

As of 100 PM Wednesday...

There is high confidence in VFR conditions to start the TAF period. Tonight, within an increasingly warm and moist airmass, areas of fog will develop mainly at FAY, RWI. Confidence is highest at FAY and lower at RWI. Much of the probabilistic information from the HREF/NBM and operational HRRR support this potential. While confidence is lowest at RDU, introduced a TEMPO for MVFR Thu morning as some guidance suggests the fog could extend as far north as the Triangle. Any fog should disperse by mid-morning as southwest winds develop, with occasional gusts to 18 kt. A brief period of MVFR ceilings may be possible late Thu morning before 18z, but confidence was too low to mention at this time.

Outlook: Areas of fog will be possible again Fri/Sat morning, with the best potential at FAY, RWI. A slow-moving frontal system may bring a chance of some showers and associated restrictions Sun and Mon.

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

March 8: KGSO: 83/2000 KFAY: 87/1974

March 9: KGSO: 81/1974 KRDU: 84/2009

March 10: KGSO: 78/2016 KRDU: 81/1974 KFAY: 84/1974

Record High Minimum Temperatures:

March 5: KFAY: 63/1976

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

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

March 8: KGSO: 57/1946 KRDU: 60/1946 KFAY: 63/1961

March 9: KGSO: 61/1921 KRDU: 61/1921 KFAY: 62/1980

March 10: KGSO: 58/2016 KRDU: 57/2020 KFAY: 65/1964

RAH WATCHES/WARNINGS/ADVISORIES

None.