textproduct: Raleigh

WHAT HAS CHANGED

As of 300 AM Wednesday...

.A Winter Weather Advisory has been issued from 600 PM tonight through 1000 AM Thursday for all but the SW Piedmont.

Snow amounts are generally confined mainly on the north sides of the Triad to the Triangle, and less than 0.5 inch late this afternoon and tonight.

Ice amounts are generally the same, with concerns of a few hundredths to a very light glaze in most areas tonight when temperatures fall below 32.

Flash freeze may occur tonight as temperatures crash into the 20s from north to south overnight.

KEY MESSAGES

As of 300 AM Wednesday...

Winter Weather Advisory starts at 600 PM today.

1) Rain will be likely, off an on today. The rain is expected to change to light snow and freezing drizzle over the northern Piedmont late this afternoon into the overnight period. Only light accumulations are expected. Elsewhere, the rain is expected to mix with and change to light freezing rain and freezing drizzle tonight. A light glaze is expected. Ice accumulations of a trace to a few hundreds can create very hazards travel.

2) There may be a quick freeze of residual snow/ice/water in most areas tonight as the temperatures crash into the 20s. Concerns are with hazardous travel, even if very little snow/ice accumulate.

3) There could be a brief period of precipitation along the Virginia border Sat aft/eve, however confidence is still low at this time.

4) Arctic high pressure will build in over the weekend and linger into early next week, keeping temperatures below normal.

KEY MESSAGE 2

There may be a quick freeze of residual snow/ice/water in most areas tonight as the temperatures crash into the 20s.

Most guidance suggests a potential flash freeze tonight over much of the Advisory area. The temperatures are expected to fall into the 20s overnight. The 32 degree wet bulb forecasts suggest the northern areas will fall below 25 and the far south below 30 between 06z and 12z/Thursday increasing confidence. We ran the Advisory through late morning Thursday as the freezing temperatures will be slow to moderate Thursday in the low level CAA.

Precipitation will end in the east and south by around 11z-12z Thursday. We maintained a 20-30 POP just past 12z/Thu to account of any slower exit.

3) There could be a brief period of precipitation along the Virginia border Sat aft/eve, however confidence is still low at this time.

A s/w aloft will swing across the region Fri aft/eve, which could result in a brief period of light precipitation along the NC/VA border. However, chances and confidence remain low at this time.

4) Arctic high pressure will build in over the weekend and linger into early next week, keeping temperatures below normal.

A ~1034 mb Arctic high will track SSE across central Canada and into the upper MS Valley/wrn Great Lakes Fri/Fri night, then continue ewd across the Great Lakes/OH Valley Sat/Sat night. The high will ridge esewd across the Appalachians and into the mid-Atlantic/Carolinas as it moves across the OH Valley, with nwly flow advecting Arctic air into the area. The high will begin to weaken a bit as it moves into/across the Northeast US Sun/Sun night, while continuing to ridge sswwd into the area. The coldest period will be Sat through Sun, with highs ranging from mid/upr 30s NE to upr 40s/low 50s SW and lows Sat night in the teens to low 20s. Temperatures will remain below normal Sun night, with lows in the 20-30 degree range. There is uncertainty wrt how long the ridge/Arctic air will hold over central NC into next week, but a general moderating trend is expected Mon-Tue, with near to above normal temperatures possible by Tue/Tue night.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

As of 650 AM Wednesday...

24 Hour TAF Period: Sub-VFR conditions will develop later this morning through today as a cold front moves into the area from the north. A few light showers will be possible overnight , followed by an area of low pressure and more widespread rain this afternoon, mainly from RDU south and east to RWI and FAY.

Ceilings are expected to lower to IFR and LIFR through the day, expanding to all the region by late day. The rain may change to a period of freezing rain and snow across the KINT to KRWI areas including GSO and RDU between 23z and 02z, and spreading south between 03z and 06z. Widespread IFR to LIFR conditions are expected tonight. The precipitation will likely end before daybreak Thursday. Outlook: A return to VFR conditions will occur Thursday and should generally continue through the weekend.

RAH WATCHES/WARNINGS/ADVISORIES

RAH WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory from 6 PM this evening to 10 AM EST Thursday for NCZ007>011-021>028-038>043-073>078-086-088-089.