textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Rain chances have increased 10 to 20% for Saturday and Sunday, as confidence is increasing on a front approaching from the northwest.

KEY MESSAGES

1. Cold air damming weakens today, but lingering moisture will contribute to the possibility of patchy dense fog early Wednesday morning that could impact the morning commute. 2. Well above normal temperatures for the rest of the week and through the weekend. It will be generally dry, but rain chances expected to return by Sunday.

DISCUSSION

Key message 1: Cold air damming weakens today, but lingering moisture will contribute to the possibility of patchy dense fog early Wednesday morning that could impact the morning commute.

A parent high situated off the New England Coast is expected to drift farther offshore throughout the day while supporting a relatively weak cold air damming wedge east of the mountains. The lack of widespread measurable rainfall will keep the wedge relatively weak on today, and so the guidance looks reasonable in allowing temps to return back to normal in the mid/late afternoon.

If there is a concern in the near term, it might be the potential for patchy dense fog early Wednesday morning over the NC foothills. Moisture is expected to slowly increase Tuesday afternoon as the low level flow veers around to light southerly while upper levels dry out. A weak sfc high remnant may linger over the western Carolinas, allowing for light/variable wind overnight, setting the stage for fog development. Guidance from the HREF shows the chances of visibility under one half mile to be 40-50 pct at best, but the ingredients for patchy dense fog will be there. Low temps will be seasonally mild.

Key message 2: Well above normal temperatures for the rest of the week and through the weekend. It will be generally dry, but rain chances expected to return by Sunday.

Upper ridge will build across the Southeast Wednesday, then shift to the East Coast and continue amplifying thru the weekend, while deep troughing occurs in the western CONUS. This pattern will allow temps to ramp up to 15 to 20 deg above normal for the latter half of the week and thru the weekend. Confidence continues to increase on temps reaching the lower 80s across most of the Piedmont by Friday and continuing thru at least Sunday. These will approach records, especially March 6th, which has lower, more reachable record highs. Dew points and min temps will increase as well, thanks to a moist SWLY flow out of the Gulf, making for a summer-like pattern. Lows may be close to our normal highs (near record high minimums). Isolated to widely scattered diurnal convection may begin Friday, increasing in coverage for Saturday and Sunday, as a cold front sags southeast toward the CWFA. The latest NBM has trended higher on PoPs over the weekend, with likely PoPs for Sunday. It's too early to say how much of a severe threat there will be with any thunderstorms that develop, but there looks to be a non-zero threat of at least a few strong storms, with some bulk shear to go along with increasing instability.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

At KCLT and elsewhere: MVFR cigs are locked in across the terminals as winds continue to flow from the east-northeast. Placed a prevailing MVFR cig at all the TAF sites and kept the restriction going through at least 18Z as guidance keeps the stubborn layer in place without much scattering through the morning hours. Winds will continue to run out of the northeast through the morning before turning southeasterly by the afternoon at 4-8 kts. KAVL will maintain a southerly component through much of the period. Cig restrictions will scatter late in the afternoon, but guidance hints at redevelopment tonight, with the possibility of fog developing at terminals where the clouds scatter out more. As a result, brought MVFR cigs back into the TAF by the end of the period, with a hint of fog through daybreak Tuesday.

Outlook: VFR is expected to return on Wednesday, while another cold front may bring showers and associated restrictions for the weekend.

CLIMATE

RECORDS FOR 03-05

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 78 1955 20 1960 60 2004 5 1960 KCLT 84 1955 31 1960 62 1955 12 1960 1880 KGSP 80 1976 31 1960 61 2004 12 1960 1905 1976 1961

RECORDS FOR 03-06

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 78 1908 28 1960 58 1961 5 1960 KCLT 80 2022 33 1901 62 1961 10 1960 KGSP 79 1974 37 1948 63 1961 16 1960 1915 1901

RECORDS FOR 03-07

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 82 1974 23 1920 61 1956 15 1960 KCLT 85 1974 30 1899 63 2022 14 1899 1956 KGSP 83 1974 36 1920 62 1961 13 1901 1901 1956

RECORDS FOR 03-08

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 81 1974 23 1996 57 1921 8 1920 KCLT 84 1974 36 1989 59 1946 16 1920 KGSP 84 1974 35 1899 56 1921 14 1901 1899

RECORDS FOR 03-09

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 80 1974 22 1932 57 1964 8 1996 KCLT 83 2009 30 1960 62 1925 16 1996 1974 1921 1925 KGSP 85 2009 29 1960 60 2009 16 1996 1921

RECORDS FOR 03-10

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 76 1974 29 1932 58 1903 10 1996 1932 KCLT 82 1974 36 1924 59 1903 17 1932 KGSP 84 1974 39 1924 58 2009 17 1932 1997

GSP WATCHES/WARNINGS/ADVISORIES

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