textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Updated the aviation discussion for the 12z TAFs.

KEY MESSAGES

1. Expect well-above normal temperatures today with light winds and low humidity this afternoon. Relative humidity values will remain low each afternoon thru at least the first half of next week, leading to increased fire danger each day. 2. Dry and hot next week with no significant drought relief in sight. Daily record highs in jeopardy starting Tuesday through the end of next week.

DISCUSSION

Key message 1: Expect well-above normal temperatures today with light winds and low humidity this afternoon. Relative humidity values will remain low each afternoon thru at least the first half of next week, leading to increased fire danger each day.

Broad upper ridging will continue to build eastward today and tonight as upper trofing moves off the New England Coast. At the surface, a weak, mostly dry back-door cold front will move south across our area today. Minimal sfc-based instability, up to about 500 J/kg, is expected to develop ahead of the front. We could see a few scattered showers with some isolated thunder, mainly along the I-77 corridor late this afternoon and evening as the boundary crosses the area. Any precipitation amounts should be minimal. Otherwise, dry conditions will continue with near-critical RH likely across most of our fcst area today. Fortunately winds will be light, which should help decrease the overall fire danger.

Key message 2: Dry and hot next week with no significant drought relief in sight. Daily record highs in jeopardy starting Tuesday through the end of next week.

Southeast ridging will keep anomalously high heights into the region for next week. The ridging essentially blocks any frontal boundary from coming this far east, which allows for the heat to build. The first really warm day is forecast to be on Tuesday with highs in the mid to upper 80s. Expect temperatures to reach near 90 to low 90s east of the mountains starting Wednesday through the end of the week, with mid to upper 80s in the major mountain valleys. The synoptic pattern will be similar to late June/early July as daily record highs will be in jeopardy during the extended forecast period. Only light moisture return will be associated in this setup with very warm air aloft, so any convective chances will be suppressed. Some of the deterministic guidance has a frontal boundary reaching far enough south to potentially provide some convective activity in the mountains by late next week, but confidence is low in this development at this time.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

At KCLT and elsewhere: Expect dry, VFR conditions to continue through the 12z taf period. Sfc high pressure will remain over the region thru the period, despite a weak back-door cold front moving south over the area today. The front could produce some sct VFR clouds and a brief/weak, NLY/NWLY wind but that's about it. The sfc high gets reinforced from the north in the front's wake keeping things dry. Winds should remain calm to light and VRB thru the morning and favor a S to SW direction this afternoon at the Upstate terminals despite the weak fropa. They will likely favor a light, NW direction at KCLT and KHKY this aftn/evening, but could certainly be VRB at times. Both sites will favor a NE direction overnight, with KCLT going S of E by the end of the taf period tomorrow aftn. At KAVL, winds will remain light and VRB to calm thru the morning and pick up marginally from the N this aftn. They should go light and VRB to calm again later this evening.

Outlook: Expect dry, VFR conditions to continue thru early next week.

CLIMATE

RECORDS FOR 04-14

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 86 2006 36 1907 62 1922 24 1950 KCLT 89 1941 46 1907 69 1922 27 1950 KGSP 92 1916 48 1901 67 1922 22 1907

RECORDS FOR 04-15

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 89 1972 42 1943 64 1887 23 1907 KCLT 89 1936 46 1889 66 2006 28 1907 KGSP 91 2006 45 1913 69 1922 22 1907

RECORDS FOR 04-16

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 87 2006 42 1905 62 1945 26 1943 KCLT 89 2006 49 1890 64 1998 29 2008 1896 1991 1962 1945 KGSP 88 1888 54 1903 64 1945 24 1907

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

GSP WATCHES/WARNINGS/ADVISORIES

GA...INCREASED FIRE DANGER from noon EDT today through this evening for GAZ010-017-018-026-028-029. NC...None. SC...None.