textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

An increase in fire danger is possible Tuesday afternoon.

Rainfall amounts/chances continue to trend slightly higher for the entire area for a system crossing the region during the middle part of the midweek.

KEY MESSAGES

1. Generally dry and seasonal Tuesday, with some minor concerns for increased fire danger in the afternoon. A Fire Danger Statement is not anticipated. 2. Another cold front brings rain to the area on Wednesday and Thursday. At this time, the threat for severe thunderstorms and excessive rain still appears to be low.

DISCUSSION

Key message 1: Generally dry and seasonal Tuesday, with some minor concerns for increased fire danger in the afternoon. A Fire Danger Statement is not anticipated.

After a transition day today, a more gradual warmup and increase in moisture is expected for Tuesday with sfc high pressure off the East Coast and an open Gulf allowing for some low level moisture advection. The main concern will be the dry air above the subsidence inversion seen on fcst soundings, because if we can tap into that layer the dewpoint will mix out again lower than what we have in the forecast, possibly dropping the min RH well down into the 20 percents. For now the chances of that appear to be small, but we have mixed in some of the drier guidance to hedge on the drier side, which brings the min RH down to around 30 pct in spots across the foothills and western Piedmont of NC. The improving pressure gradient ahead of the front still located well to our NW in the afternoon could contribute occasional wind gusts of 20-25 mph, so there is some concern for increased fire danger. But, we've already greened up outside the mtns, which limits the overall concern. We shall monitor.

Key message 2: Another cold front brings rain to the area on Wednesday and Thursday. At this time, the threat for severe thunderstorms and excessive rain still appears to be low.

The latest model guidance hasn't trended significantly, so we maintain the status quo with regard to the severe weather and excessive rain threats for the upcoming system expected to affect our region beginning early Wednesday and continuing through Thursday. Confidence is higher in rain chances as we still have a lot going for us in terms of an open Gulf and a slow-moving front, so categorical precip probs are a good bet. Amounts are still uncertain, but the chances for getting more than an inch of rain have crept upward a bit more compared to this time yesterday, mainly over the western half of the forecast area. Note that most of the forecast area is in a Marginal Risk for excessive rainfall for Wed/Wed nite, but there are limiting factors. Some of the guidance continues to show deeper convection moving past to the south across the I-20 corridor early Thursday, which would cut back on our precip amounts to the north. We will be able to re-evaluate by this time tomorrow, when the CAMs will go out far enough in time to capture most of the event. The thinking about the severe weather chances hasn't changed much, either. It still looks like a timing issue more than anything, which means that it might depend on whether or not anything that gets cranked up from MS into AL on Wednesday can survive to make a run at our western border. The 12Z run of the CAMs tomorrow will be enlightening. In the mean time, the threat still looks low, and we will continue to monitor.

After Thursday, high pressure returns into the weekend and keeps the weather relatively quiet and warm. Another system could affect the region Sunday and Monday.

AVIATION /18Z MONDAY THROUGH SATURDAY/

At KCLT and elsewhere: VFR at all terminals through the period. There could be an occasional wind gust from the SW this afternoon, but in general Tuesday afternoon is expected to be the more frequently gusty period. In between, just a light southerly flow with a few high thin clouds.

Outlook: VFR continues thru Tuesday night. Periodic restrictions are likely with next frontal system Wednesday and Thursday. Low forecast confidence Friday into next weekend but restrictions cannot be ruled out at that time.

GSP WATCHES/WARNINGS/ADVISORIES

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