textproduct: Raleigh

WHAT HAS CHANGED

As of 130 PM Tuesday...

* Remaining above normal through Wed with highs some 10-15 degrees above normal.

* Rain chances Wed still in the forecast, but amounts are on the low end with a tenth of an inch or less.

KEY MESSAGES

As of 130 PM Tuesday...

1) Staying above normal through Wed with highs 10-15 degrees above normal. Fire danger concerns are possible over the northwest Piedmont Wed afternoon.

2) Rain chances with a cold front on Wed are highest in the Sandhills and Coastal Plain of central NC.

3) High confidence in a period of at least light to moderate rain late Sat night through Sun. Forecast details, such as amounts and areal coverage, remain highly uncertain.

DISCUSSION

As of 130 PM Tuesday...

KEY MESSAGE 1... Staying above normal through Wed with highs 10-15 degrees above normal. Fire danger concerns are possible over the northwest Piedmont Wed afternoon

Temperatures will hover above normal today and continue into tomorrow, even with the passage of a cold front during the early part of the day. A warm front continues to lift northward this afternoon and should propel our highs finally some 10-15 degrees above normal. Highs should reach the low to mid 60s in the east and mid to upper 60s in the west and southwest. Temperatures tonight will also be much more mild than the past few weeks with lows some 15-23 degrees above seasonal averages in the mid 40s to low 50s.

Tomorrow, a pair of cold fronts will move through. The first one passes through during the mid-morning and early afternoon hours. This first one will not be as cold as the second one, which comes in Wed evening, bringing upper 20s to low 30s Wed night and highs Thu in the upper 40s to upper 50s. Dry downslope northwest winds with the initial cold front will make for a gusty but also another warm day with highs once again in the low 60s NW to mid/upper 60s SE. Northwest winds could gust into the 15-25 mph range during the afternoon. As downslope flow and drier air works in, dewpoints will crash into the 20s over the Piedmont. A period of marginal increased fire danger may occur between the late morning hours and early evening in this region where RH levels dip into the mid/upper 20s. We reached out to the NCFS and a fire danger statement may be needed. Further consultation with NCFS will occur later today.

KEY MESSAGE 2... Rain chances with a cold front on Wed are highest in the Sandhills and Coastal Plain of central NC

The initial cold front pushing through on Wed will continue to bring a chance of rain, mainly during the morning hours, with activity skirting off to the southeast in the early afternoon. The 12z HREF guidance continues to show limited rainfall amounts. In fact, while precipitation chances are elevated in the 50 to 80 percent chance range along/east of US-1, forcing for ascent is not overly impressive. Median and LPMM rainfall amounts from the HREF suggest a few hundredths of an inch around the Triangle, to maybe a tenth of an inch in the Sandhills and southern Coastal Plain. Little if any rain is expected in the Triad. The 90th percentile shows only a quarter of an inch in the south. So definitely not a drought buster by any means. Any rain ends by early afternoon, with sunshine taking hold over most of the region.

KEY MESSAGE 3... High confidence in a period of at least light to moderate rain late Sat night through Sun. Forecast details, such as amounts and areal coverage, remain highly uncertain.

An initially closed southern stream mid/upper level trough off the CA coast will kick eastward Fri and is expected to shift across the Southeast and southern Mid-Atlantic this weekend. NWP guidance is struggling with its evolution east of the Rockies and is resulting in a large range of solutions for the Carolinas. There is still a high degree of confidence in at least widespread light, and measurable rain, but the moderate to heavy rainfall footprint remains highly uncertain.

There is still a large spread in the speed and latitudinal track of this southern stream wave between the faster and farther north CMC, and the slower and farther south GEFS. The EPS, AI- GEFS, and AIFS are a good middle ground and show a reasonable low-end scenario of trace to 0.25" across the forecast area, greatest amounts towards the NC/SC border. Probabilities of > 1" have come down slightly from the 12z Mon models and now range from 25-40%. Probabilities of these higher amounts remain greatest in the Foothills and western Piedmont (signaling an upslope pattern) and lowest in the Coastal Plain into northeast NC.

Alternate scenarios: There has been a general trend south of the southern stream wave within the NWP guidance which is making the likelihood of precip lifting north into VA less likely, but if it trends too far south (the 12z GEFS solution) the probabilities of > 1" plummet to around 10%. Conversely, if the track trends towards the mid-ground solutions, reasonable high- end amounts of 1-2" would be possible basically anywhere across the forecast area.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/

As of 1235 AM Wednesday...

TAF period: High confidence in VFR conditions overnight, with the only possibility for ceiling/vis restrictions coming Wednesday morning with rain showers. Low-level wind shear will continue at all sites through the overnight hours, diminishing as a cold front moves through around daybreak from northwest to southeast. High clouds will drop in height overnight. Removed the TEMPO group for rain at INT/GSO - there is still a chance of rain, but not high enough to mention at this time. Have continued with a TEMPO group at RDU for rain and prevailing rain at FAY/RWI, with the highest chances of rain being to the south and east. This is also when MVFR conditions would have the greatest chance. Wind out of the southwest overnight will veer to the northwest after the cold front moves through, but have slightly lowered the expected gusts in the afternoon looking at newest guidance. The atmosphere may remain mixed enough for gusts to continue this evening, but did not have enough confidence to continue the overnight gusts at this time.

Outlook: Dry VFR conditions are expected until Saturday night into Sunday, when widespread rain and restrictions will move into the region from west to east.

RAH WATCHES/WARNINGS/ADVISORIES

None.