textproduct: Raleigh

WHAT HAS CHANGED

As of 215 AM Tuesday...

The likelihood of rain has increased Wednesday, along with the probabilities that the rain will mix with and change to light snow Wednesday afternoon and night from the north.

KEY MESSAGES

As of 215 AM Tuesday...

1) Very cold temperatures continue this morning with icy driving conditions persisting. Moderating temperatures this afternoon into the 40s will aid in melting process. Temperatures with cloudiness tonight may stay slightly above 32.

2) Rain is expected late tonight into Wednesday. The cold front will shift south through the region Wednesday afternoon. As colder air rushes in from the north late Wednesday and Wednesday night, the probabilities of a change to snow at the end of the event have increased (especially Wednesday night). Precipitation will end by 12z or so Thursday.

3) Well below normal temperatures will persist through next weekend as a few rounds of Arctic air return Thursday into the weekend.

DISCUSSION

As of 215 AM Tuesday...

KEY MESSAGE 1... Very cold temperatures continue this morning with icy driving conditions persisting. Temperatures with cloudy skies tonight may remain above 32 in many areas.

The Special Weather Statement for icy secondary roads and patchy black ice elsewhere continues through mid-morning. Temperatures in the teens and 20s early will warm above 32 during the mid to late morning. This will allow some improvement to begin again. The increase in cloudiness this morning through the day will limit direct sunshine for melting. However, the SW flow will allow temperatures to moderate under the veil of cloudiness. Highs generally in the 40s are expected.

Good news for tonight, the SW flow and cloudy skies along with slowly increasing dew points (low level moisture) will likely keep temperatures above 32 for most locations. This should allow some additional melting, even after dark. Of course, the snow/ice covered ground is very cold, thus the melting will be limited there.

KEY MESSAGE 2... Rain chances have increased Wednesday. And, probabilities of a change to snow Wednesday night with a light accumulation have increased.

There is now a stronger wave of low pressure shown by most model solutions that will track ENE along a southward moving cold front late Wednesday into Wednesday night. While most of Wednesday (ahead of the cold front)will be too warm aloft to the surface for snow, rain is expected to overspread the region. However, the wave depicted now is a bit stronger with more moisture and lift expected as it tracks ENE along the NC/SC border Wednesday night. Rain is expected to become mixed with and change to light snow from north to south late Wednesday afternoon (VA border) throughout most of the region during the evening and overnight.

A good portion of the precipitation will likely be rain with temperatures in the mid 30s to mid 40s north to south for highs, with at least half the expected QPF to be rain. However, as the transition occurs, there are increasing probabilities of a change to light accumulating snow overnight. In the areas around FAY to Clinton to GSB, there may be a little wintry mix as the entire temperature profile (a lingering mid level warm nose and slower wet bulbing below 32 may become problematic there.

The current snowfall probabilities are depicting a higher potential of up to 1 inch of snow north, with lower probabilities south and east due to the slower cooling of the entire column there until close to the end of the precipitation event. Probabilities of 3 inches of snow are still less than 30 percent. Regardless, chances have increased in at least some accumulations as temperatures crash into the 20s north and lower 30s SE Wednesday night. For now, we will carry 1 inch or less in all but the SE.

If these trends continue, a Winter Weather Advisory may be needed for at least part of central NC late Wednesday and Wednesday night.

KEY MESSAGE 3)... Very cold, well below normal temperatures will persist through next weekend as a few rounds of Arctic air return Thursday into the weekend.

After the passage of the precipitation event by 12z/Thursday, the period of Thursday through Sunday will remain below to well below normal temperature wise. A few rounds of cold, mostly dry air look to make their way to central NC during this time frame. Thus, Thursday looks to be the coldest day of the period, with highs in the mid 30s to low 40s and lows in the upper teens to low 20s. Friday and Saturday will moderate some ahead of an approaching cold frontal passage Saturday, with highs in the 40s to low 50s. Also ahead of the cold front, a brief period of very light snow may be possible in the northeast Friday morning associated with a shortwave trough that looks to pass to our north. Lows look to dip into the upper 20s to low 30s Friday night, dropping back into the upper teens to mid 20s on Saturday night and through the weekend.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

As of 640 AM Tuesday...

Arctic high pressure and dry air will favor VFR conditions over cntl NC through this morning. A veil of considerable high level cloudiness and associated 15-25 thousand ft ceilings will overspread cntl NC today and persist tonight with added low and mid clouds increasing between 03z and 12z tonight from the W and SW. Outlook: Flight restrictions and a chance of rain will result with the approach and passage of a frontal wave Wed and Wed night; and that rain may change to a period of snow before ending Wed night. A return to VFR conditions will occur Thursday.

RAH WATCHES/WARNINGS/ADVISORIES