textproduct: Raleigh

WHAT HAS CHANGED

As of 215 PM Tuesday...

-Snow amounts remained largely the same, however ice amounts have increased as the probability of freezing rain across the southeastern half of the CWA have increased.

KEY MESSAGES

As of 215 PM Tuesday...

1) Rain starting late tonight through Wednesday will transition to a brief period of wintry mix or light snow late Wednesday night into early Thursday, with minor accumulations possible.

2) Several reinforcing shots of Arctic air are expected late this week through the weekend.

DISCUSSION

As of 215 PM Tuesday...

KEY MESSAGE 1... Rain starting late tonight through Wednesday will transition to a brief period of wintry mix or light snow late Wednesday night into early Thursday, with minor accumulations possible.

Surface high pressure over the Upper Mississippi Valley this afternoon will gradually shift southeast through Wednesday. Meanwhile, a surface boundary extending from eastern Texas into the Tennessee Valley, associated with a surface low, will inch eastward into the Mid-Atlantic by late this evening. The surface low is expected to track across Tennessee, then through Georgia and South Carolina, and move offshore by Thursday morning.

As the associated cold front approaches, rain will overspread central North Carolina overnight into early Wednesday morning. Thermal profiles at the surface and aloft will remain too warm for frozen precipitation through most of the day Wednesday, resulting in predominantly liquid precipitation.

Cold air advection from the northwest will increase late Wednesday evening, with ensemble guidance indicating precipitation transitioning to a wintry mix and eventually snow as moisture exits the region. The timing of this transition remains somewhat uncertain, but areas along and north of the I-85 corridorand possibly the northern Coastal Plaincould see a changeover as early as late Wednesday evening. As northerly flow strengthens overnight, precipitation is expected to transition to all snow across much of the area into the pre-dawn hours Thursday.

For areas south and east of the Triangle, a shallow warm nose may persist, supporting a period of freezing rain or sleet before ending as light snow early Thursday. Precipitation will taper off quickly Thursday morning, with lingering moisture mainly confined to the coast.

Accumulations are expected to be light overall, with the greatest snow totals near the Virginia border as temperatures fall into the 20s prior to precipitation ending. Should trends continue to support snow accumulations of around 1 inch or greater, or impactful ice accretion, a Winter Weather Advisory may be needed late Wednesday night into early Thursday morning.

KEY MESSAGE 2...Several reinforcing shots of Arctic air are expected late this week through the weekend.

A series of fast moving shortwave troughs embedded within northwesterly flow will bring reinforcing shots of cold air to the region. For the most part these waves will sweep through absent of any precip, although there may be just enough moisture ahead of a wave on Friday to support some isolated rain/snow along the NC/VA border. More than anything, these waves will keep temperatures in check with daytime highs remaining well below normal for early February. With the exception of Thursday (which will see highs in the upper 40s), daytime highs will generally stay in the upper 30s to mid 40s, with overnight lows in the mid 20s to around 30.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

As of 120 PM Tuesday...

24 Hour TAF Period: VFR conditions will continue for today, before sub-VFR conditions return tonight as surface high pressure over the southeastern U.S. shifts offshore today and an a cold front approaches and moves into the area tonight into Wednesday. This will allow for chances of rain and IFR/LIFR conditions to develop overnight into Wednesday. Also, a period of LLWS will be possible late this evening into the pre-dawn hours of Wednesday. Outlook: Flight restrictions and a chances for rain will continue Wednesday afternoon into Wednesday night as a wave of low pressure tracks along the stalled frontal zone just to the south of central NC. Also the rain may change to a period of snow and/or freezing drizzle Wednesday evening/night before ending. A return to VFR conditions will occur Thursday.

RAH WATCHES/WARNINGS/ADVISORIES