textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

No changes to any of the Wind or Winter Weather headlines with this foreacast package.

Increased Fire Danger statement issued for NE Georgia today, 11 AM to 7 PM EST.

A little more freezing drizzle and sleet possible along the TN border than previous forecast, but still expect mostly snow through daybreak.

KEY MESSAGES

1. Winter Weather Advisory remains in effect for Madison/Yancey/Mitchell/Avery counties through 7 am Saturday for additional snow accumulation that will result in some travel impacts. 2. A High Wind Warning remains in effect till 7 PM this evening for portions of the NC mountains near the Blue Ridge Escarpment, along with a Wind Advisory for the rest of the mountains and much of the Piedmont. These conditions may knock down tree limbs and cause power outages. Stronger winds will increase the likelihood of those impacts but also could be associated with minor structural damage. 3. A Cold Weather Advisory remains in effect for portions of the North Carolina mountains early this morning through early Sunday morning as dangerously cold wind chills could result in hypothermia or frostbite if precautions are not taken. 4. High pressure keeps dry conditions around through Tuesday, outside of some brief light snow in the northern North Carolina mountains Sunday morning. A cold front brings better precipitation chances back starting late Tuesday night, with chances possibly lingering through the rest of the workweek. 5. Below normal temperatures stick around Sunday before warmer and above normal temperatures return for most of the workweek.

DISCUSSION

Key message 1: Winter Weather Advisory remains in effect for Madison/Yancey/Mitchell/Avery counties through 7 am Saturday for additional snow accumulation that will result in some travel impacts.

Moisture has become shallow across the mountains in the wake of a passing cold front, but cloud top temps are in the -10 to -15 C range, which supports ice nuclei activation. There are plenty of low clouds upstream, but are rather shallow with little radar echoes across KY/TN attm. There may be mostly freezing drizzle or rime ice going on over the mountains near the TN border, but still expect snow showers to pick up, as upslope flow increases and temps within the moist layer decrease. Additional snow amounts still expected to be around 1 to 4", with highest totals in the highest elevations near the TN border. The 7 am end time for the Winter Weather Advisory still looks good.

Moisture really diminishes quickly after 12z this morning, but strong wind gusts may cause some blowing snow that would reduce the visibility at times thru late morning, especially in the Northern Mountains above 3500 ft.

Key message 2: A High Wind Warning remains in effect till 7 PM this evening for portions of the NC mountains near the Blue Ridge Escarpment, along with a Wind Advisory for the rest of the mountains and much of the Piedmont. These conditions may knock down tree limbs and cause power outages. Stronger winds will increase the likelihood of those impacts but also could be associated with minor structural damage.

Forecast remains on track for the wind event this morning, lingering thru the day across the region, as a strong 60-70 kt jet at 850 mb will maximize along the Blue Ridge Escarpment in the 09-15z time frame. Strong cold air advection and sfc pressure rises along the Appalachians support strong wind gusts, with deep mixing tapping into high-momentum flow. The latest guidance still supports gusts approaching advisory criteria out away from the escarpment across the foothills and much of the NC Piedmont. The current High Wind Warning and Wind Advisory areas seem well-placed and no changes are planned. Parts of the products may be able to be cancelled early and 850 mb winds will gradually weaken and gusts should follow suit, especially away from the Escarpment.

As gusty winds linger into the aftn, RH will plummet below 25% across most of the forecast area except above 3500 and near the TN border. These conditions usually result in elevated danger of wildfires, but land management agencies in NC/SC have reported fuels are still too wet following the recent winter storms and snow melt to support the level of risk that would warrant an Increased Fire Danger Statement. In GA 10-hr fuel moistures probably will drop below 8% in the dry/windy weather today, so a Statement will be issued there per state criteria.

Key message 3: A Cold Weather Advisory remains in effect for portions of the North Carolina mountains early this morning through early Sunday morning as dangerously cold wind chills could result in hypothermia or frostbite if precautions are not taken.

Temperatures still expected to plummet across the high terrain thru daybreak, gusty winds reach their peak. Wind chill values will get into the -5 to -15 deg F range by 7 am Sat across much of Avery County and above 3500 ft in the rest of the NC mountains. Temps don't warm up much today, while winds remain strong. So wind chills only expected to rise into into the single digits above zero for a few hours during the aftn, before dropping again tonight, with potential of getting below -5 again for a few hours overnight. No changes planned for the Cold Weather Advisory, which continues to 7 am Sunday. These dangerously cold wind chills could result in hypothermia or frostbite if precautions are not taken. Use caution while traveling outside. Wear appropriate clothing, a hat, and gloves.

Key message 4: High pressure keeps dry conditions around through Tuesday, outside of some brief light snow in the northern North Carolina mountains Sunday morning. A cold front brings better precipitation chances back starting late Tuesday night, with chances possibly lingering through the rest of the workweek.

Broad upper troughing lingers over the Southeast Sunday into Monday with periodic shortwaves tracking across the western Carolinas and northeast Georgia during this time. At the surface, dry high pressure will slowly sink southward over the eastern United States through Monday night. The northwestern periphery of the high will remain extended over the region through Tuesday ahead of an approaching cold front keeping dry conditions around for most locations. The exception will be the northern North Carolina mountains as the 00Z CAMs show light snow developing Sunday morning in association with a shortwave diving across the forecast area. Thus, added slight chance PoPs across Avery, Mitchell, and Yancey counties Sunday morning to account for this potential. Any snow that develops should remain light, so little to no accumulation is expected at this time.

Rain chances may return as early as Tuesday night ahead of the aforementioned cold front across the North Carolina mountains, per the GFS. However, the ECMWF and Canadian show rain chances holding off until Wednesday morning. Thus, confidence on PoPs Tuesday night across the mountains remains low at this time. The cold front will track across the forecast area late Wednesday before pushing east of the area by daybreak Thursday, keeping rain chances around through Wednesday night. A reinforcing cold front appears to track across the forecast area Thursday into Friday keeping rain chances around through the end of the workweek, which global models appear to be coming into better agreement on. The main p-type is expected to be rain for most locations. However, depending on how much cold air builds into the region behind the second front, wintry p-types may return Thursday night and Friday night across the northern North Carolina mountains.

Key message 5: Below normal temperatures stick around Sunday before warmer and above normal temperatures return for most of the workweek.

Upper ridging builds into the region from the west Monday evening into Tuesday before flattening out Tuesday night into Wednesday. Another bout of weak upper ridging builds back over the Southeast Wednesday night into Thursday. This will allow much warmer and above normal temperatures to return for much of the workweek. Highs on Sunday will remain cool and a few to several degrees below normal before a warming trend develops Monday through Wednesday. Highs climb into the mid to upper 60s across the lower elevations Tuesday afternoon, reaching into the mid 60s to lower 70s east of the mountains Wednesday afternoon. Although highs on Tuesday and Wednesday will end up 10-15 degrees above normal, we do not appear to get close to record highs at any of the climate sites these days. A cooling trend develops Thursday into Friday but highs will remain above normal Thursday before trending more towards normal Friday.

AVIATION /06Z SATURDAY THROUGH WEDNESDAY/

At KCLT and elsewhere, except KAVL: VFR expected at all terminals, and mainly SKC this morning. A few stratocumulus developing in mountain wave may be seen particularly near KCLT and KHKY, possibly causing slant-range vsby issues at times early this morning. The main concern will be gusty winds. Gusts have begun to pick up and gusts of 20-30 kt will continue, with frequency/magnitude generally trending upward thru daybreak. Slightly higher gusts (up to 35 kt) possible at KHKY and KGSP. Gust potential will probably increase for a time thru mid-morning then gradually taper off thru Saturday, with some sites seeing gusts drop off at sunset. Midlevel clouds at FL120-220 are likely to increase in numbers after 00z Sun.

At KAVL: Bases of the upslope-induced cloud deck near the TN border have lowered to near the MVFR-VFR threshold, cigs should go back and forth between about FL025-035 thru the early morning hours. Flurries are seen on webcams near the airport and the potential for MVFR vsby due to -SHSN will maximize in the same window, so TEMPO handles both. Gusts expected to peak near 40 kt prior to dawn and continue at similar magnitude thru the morning hours, though cigs should break up. Slow taper of gusts thru the rest of the period with high altitude cloud cover arriving tonight.

Outlook: Dry, VFR conditions are expected Sat night through early next week.

GSP WATCHES/WARNINGS/ADVISORIES

GA...Wind Advisory until 7 PM EST this evening for GAZ010-017. INCREASED FIRE DANGER from 11 AM EST this morning through this evening for GAZ010-017-018-026-028-029. NC...Wind Advisory until 7 PM EST this evening for NCZ035>037-048- 051-052-056>059-062-068>072-502-504-506-508-510. Winter Weather Advisory until 7 AM EST this morning for NCZ033- 048>050. High Wind Warning until 7 PM EST this evening for NCZ033-049- 050-053-063>065-501-503-505-507-509. Cold Weather Advisory until 7 AM EST Sunday for NCZ033-048>052- 059. SC...Wind Advisory until 7 PM EST this evening for SCZ008-101>106- 108-109.