textproduct: Raleigh

WHAT HAS CHANGED

As of 1200 AM Monday...

* Patchy black ice possible through mid-morning Monday

* This will be a week to monitor cold air and the potential for a significant precipitation event later this week or weekend.

* Increasing chance of bitterly cold temperatures late in the weekend and next week.

KEY MESSAGES

As of 1200 AM Monday...

1) Patchy black ice possible through mid-morning Monday.

2) Generally a cold week ahead, potential for a significant winter storm late week or this weekend and bitterly cold temperatures - either with, or both - with and behind - the potential system.

3) Very cold temperatures expected later this weekend into early next week.

DISCUSSION

As of 1200 AM Monday...

KEY MESSAGE 1... A Special Weather Statement has been issued for central NC through 900 AM Monday. The temperatures were already below 32 for most areas and lows will be deep into the 20s by daybreak with clear skies. Although most of the runoff from the rain will have evaporated or will evaporate overnight, there may be some areas that will have some patchy black ice through mid-day Monday. Also, prepare to do plenty of defrosting as a very heavy frost is expected.

KEY MESSAGE 2... The overall pattern favors bouts of cold air this week along with featuring the threat of a developing storm system Generally a cold week ahead, potential for a significant winter storm late week or this weekend. The coldest temperatures will likely be Tuesday into Wednesday when dry and cold arctic air will be present. Lows should bottom out in the 15-22 range both Monday night and Tuesday night. Highs will be in the mid 30s to lower 40s Tuesday and mostly in the 40s Wednesday. A brief milder period is expected Wednesday night into Friday when highs should return to the 50s to lower 60s SE. Mainly dry weather is expected through the week, with only a slight chance of a light shower with the mid level warm front Wed. night or Thu. morning.

A strong and bitterly cold arctic air mass, led by a 1050ish surface high over the northern Plains by early Friday. Depending on the timing, the surface front is expected to arrive late Friday. The arrival of the front and the amount of CAA that can occur will be critical for the next, possibly more significant system next weekend.

KEY MESSAGE 3... Very cold temperatures may result with and/or behind the potential storm this weekend. This will have to be followed this week.

Critical questions...

Will there be a significant system(s) next weekend as many models project?

Will the surface high build into the Great Lakes and NE states into a position that it will build down the eastern seaboard into NC (Before) the system arrives over the weekend?

Will there be several weak lows or one strong low pressure? (Miller A or Miller B)?

All these questions, and it will take essentially most of the week to answer them.

Some bitterly cold temperatures are favored this weekend into early next week.

AVIATION /12Z MONDAY THROUGH FRIDAY/

As of 625 AM Monday...

Expect VFR conditions today and tonight.

Outlook: VFR conditions are likely to hold through Thu, although a period of clouds and slight light shower chances are possible Thu am. Next chance for appreciable precipitation and potentially sub- VFR conditions will be this weekend.

RAH WATCHES/WARNINGS/ADVISORIES

None.