textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

A Marginal risk for severe thunderstorms has elevated confidence for Saturday, though still expecting an isolated severe storm or two.

Confidence is increasing for near record high temperatures for Sunday, especially locations east of the mountains.

KEY MESSAGES

1. A few showers and thunderstorms are possible in some of the area Saturday, with an isolated severe threat. Temperatures trend warmer through the weekend. 2. Generally low-impact weather conditions expected for the middle to end of next week.

DISCUSSION

Key message 1: A few showers and thunderstorms are possible in some of the area Saturday, with an isolated severe threat. Temperatures trend warmer through the weekend.

A stout ridge out west keeps the southeast in a persistent NW upper flow regime through the weekend. Downstream of the ridge, a weak shortwave appears to pass over the CWA Saturday, increasing shower activity chances. At this time, guidance gives a slight chance (15- 30%) for showers and thunderstorms during the later afternoon and evening hours. Upper air guidance shows a fair amount of instability during the peak heating hours of 500-1000 J/kg, meaning there is enough juice to enhance some convection. With the shortwave coming through, it could help to increase thunderstorm chances. Confidence is ticking up a bit with severe chances. The primary threat looks to be hail as steep lapse rates could help to enhance strong updrafts, leading to larger hail. The Storm Prediction Center has increased the convective outlook for Saturday to a Marginal (1/5) threat risk. With that said, an isolated severe thunderstorm or two cannot be ruled out, primarily for hail. CAM guidance shows the main area of concern would be over Upstate SC, mainly east of I-26 to the NC Piedmont. This does include the Charlotte area. Once the shortwave passes, rain chances once again disappear into at least the start of the week.

Additionally, as the ridge out west weakens, height rises downstream allow for temperatures to increase well above normal through the weekend. Current guidance makes a run for records on Sunday, as the mid 80s are on tap, especially for locations east of the mountains.

Key message 2: Generally low-impact weather conditions expected for the middle to end of next week.

Mid level ridging will be in place across the southwest and south- central states for the middle to end of next week. A couple weak and moisture starved systems will move across the northern extent of this ridge and then across our area. A couple of cold fronts will impact the area Monday and Friday with a wind shift and lower temperatures, particularly Tuesday and Wednesday. A few opportunities for light showers exist through the week, but amounts and impact should be very low.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

At KCLT and elsewhere: VFR continues through the TAF period. A few higher cirrus clouds stream in throughout the day and evening from the NW. keeping cigs SCT/FEW250 for all terminals. Strong upper winds across the mountains create an increased chance for LLWS at KAVL overnight. There could be brief LLWS at KHKY but confidence is low. No vsby concerns at this time. Low end gusts of 15-20kts possible across sites east of the mountains today before diminishing after 00z. Winds remain SW through daybreak, before becoming more WNW/NW through the day tomorrow. Showers are possible at KCLT Saturday afternoon, but chances are too low to warrant a PROB30 at this time.

Outlook: VFR conditions expected to prevail through the weekend, before brief restrictions return with isolated showers to start the week.

CLIMATE

RECORDS FOR 03-21

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 82 1948 34 1960 58 1948 14 1965 1958 KCLT 87 1935 35 1914 65 1912 18 1965 KGSP 88 1907 43 1958 60 1948 18 1965 1906 1927 1906 1921

RECORDS FOR 03-22

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 86 1907 32 1915 58 1991 15 1965 KCLT 89 1907 38 1883 64 1948 24 1965 KGSP 85 1935 42 1985 62 1948 20 1906 1914

GSP WATCHES/WARNINGS/ADVISORIES

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