textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Updated aviation discussion for 12Z TAFs.

KEY MESSAGES

1. Mostly dry through Saturday with fire weather concerns sticking around. Another Special Weather Statement for Increased Fire Danger will be in effect across northeast Georgia today from 12 PM to 8 PM. Hot conditions will return each afternoon with highs east of the mountains flirting with records on Saturday. 2. A cold front will bring only spotty beneficial rainfall to the mountains Saturday night into Sunday, with significantly cooler temperatures to follow early next week. Some frost is possible over the mountains Sunday and Monday night, so precautions might be needed to protect sensitive vegetation. Fire Weather concerns will otherwise continue, as very low afternoon RH returns. 3. Hot and dry conditions will return during the latter half of next week, with no relief in site for drought or fire weather conditions.

DISCUSSION

Key message 1: Mostly dry through Saturday with fire weather concerns sticking around. Another Special Weather Statement for Increased Fire Danger will be in effect across northeast Georgia today from 12 PM to 8 PM. Hot conditions will return each afternoon with highs east of the mountains flirting with records on Saturday.

Dry conditions will linger through much of the period. A line of convection will approach out of the west late Saturday afternoon ahead of a cold front, but the best rain chances should hold off until Saturday evening (see key message 2).

Another Special Weather Statement has been issued for Increased Fire Danger across northeast Georgia and is in effect from 12 PM to 8 PM today as relative humidity will fall below 30%. A burn ban remains in place for North Carolina until further notice and a burn ban will be in effect across South Carolina starting at 7 AM this morning, remaining in place until further notice. Thus, fire danger statements should not be needed for the western Carolinas today with burn bans in effect. Breezy southwest winds will develop Saturday ahead of the approaching cold front but will remain well below advisory criteria. With relative humidity once again expected to drop near/below 30%, fire weather concerns will return Saturday.

Temperatures will remain ~14-18 degrees above normal through the period. Highs on Saturday could flirt with records east of the mountains. Per the NBM, KGSP will have a 40% to 50% chance of T>89 degrees, a 15% chance of T>93 degrees at KCLT, and a 0% chance for T>90 at KAVL on Saturday. So, KGSP appears to have the best chance to tie or break their record high on Saturday.

Key message 2: A cold front will bring only spotty beneficial rainfall to the mountains Saturday night into Sunday, with significantly cooler temperatures to follow early next week. Some frost is possible over the mountains Sunday and Monday night, so precautions might be needed to protect sensitive vegetation. Fire Weather concerns will otherwise continue, as very low afternoon RH returns.

A cyclone will skirt the southern shores of Hudson Bay Saturday into Sunday, with attendant upper trough and cold front forecast to sweep across the Southeast and Mid-Atlantic Saturday night into early Sunday. Unfortunately, the deeper forcing associated with the upper jet max is forecast to pass north of our CWA. Meanwhile, while some degree of Gulf moisture return is expected ahead of the front, the quality of that moisture is expected to be mediocre, as precipitable water values are forecast to be below normal across the Gulf. As such, guidance depicts a narrow frontal band of showers, w/ perhaps a few embedded storms moving into the southern Appalachians Sat night, which will then struggle to maintain organization east of the crest of the Appalachians. Isolated portions of the high terrain probably will see some beneficial rainfall up to 0.25," but the vast majority of our area will see little-to-no rainfall.

The more notable change brought by the front will be a return to temperatures more sane for mid-April Sunday through Tue night. In fact, much of this time frame is expected to see below normal temps...highs 2-5 degrees below normal...with lows 5-10 degrees below normal owing to the dry nature of the air mass producing large diurnal temp ranges. Morning frost will be possible in sheltered valleys Mon night and especially Tue night...when surface high pressure is forecast to settle near the forecast area.

Otherwise, Fire Weather concerns will return...if they ever abated at all...with very low-to-critical afternoon RH forecast each day Sunday through Tuesday. For the most part, winds will not be an issue...except for Sunday...when gusts from the NW of 25-30 mph are expected across the mountains (20-25 mph elsewhere), with some brief overlap of critical wind and RH possible during the afternoon.

Key message 3: Hot and dry conditions will return during the latter half of next week, with no relief in site for drought or fire weather conditions.

As an upper ridge steadily approaches the region from the central Conus, the forecast area will remain under the influence of low level high pressure through much of next week. Temperatures will steadily modify within this air mass through, with maxes forecast to return to around 10 degrees above climo by Thursday. Meanwhile, it appears moisture return will be minimal to non-existent through Day 7, and very low-to-critical RH is expected Wed and Thu afternoon. The very warm and dry conditions will exacerbate the fire danger situation, especially across areas of the higher terrain where green-up has yet to complete.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

At KCLT and elsewhere: Dry and VFR with light winds across the terminals through the 12Z TAF period. Wind direction will start out WNW/NW this morning, turning WSW/SW for most terminals east of the mountains this afternoon. KHKY and KAVL are most likely to see winds stay WNW/NW through the period. Winds will go light and VRB to calm late this evening into daybreak Saturday. Periodic cirrus can be expected, becoming SCT to possibly BKN at times.

Outlook: Breezy winds develop in association with a cold front on Saturday, with winds becoming gusty behind the front on Sunday, especially across the mountains. The cold front may also bring brief rain chances and associated restrictions Saturday night into Sunday, mainly across the mountains. Dry and VFR conditions are expected next week.

CLIMATE

RECORDS FOR 04-17

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 89 1896 45 1890 63 1927 26 1904 KCLT 94 1896 47 1890 66 1896 30 2018 1949 KGSP 92 2006 51 1904 63 1927 25 1905

RECORDS FOR 04-18

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 90 1896 44 1921 60 1927 28 1905 1891 KCLT 93 1896 45 1983 66 1896 32 2001 KGSP 89 2002 51 1983 66 1927 28 1905 1967

GSP WATCHES/WARNINGS/ADVISORIES

GA...None. NC...None. SC...None.