textproduct: Greenville-Spartanburg

SYNOPSIS

Windy and much cooler conditions will return to the area in the wake of a strong cold front tonight through Tuesday. Near-normal temperatures return mid to late week. A low pressure system could bring rain to the area for the weekend.

NEAR TERM /THROUGH TUESDAY/

As of midday Monday:

Key message 1. Gusty west to northwest winds across the area this afternoon and evening, remaining strong over the mountains through early Tuesday.

Per surface dewpoint gradient and pressure rises, cold front appears to have pushed through most of the CWA and should exit to the east over the next hr or two. Gusty winds sustained at 15-25 mph with gusts largely 25-40 mph are being reported in the wake of the front. Dewpoints have plummeted but temps have remained steady or are falling slightly such that relative humidity has been kept in check. While a few spots probably will experience RH and wind that might justify a Fire Danger Statement on those conditions alone, fuel moisture is running high following the damp wedge which just eroded. Starting to see some Wind Advisory level gusts in the northern foothills which fits with Advisory beginning as of this issuance. While gusts will diminish east of the mountains as temps fall more precipitously around/after sunset, gradient holds strong and the mountains should see gusts peak overnight and remain largely above 45 mph through 12z Tue. Most guidance shows winds falling just enough to maintain advisory expiration at that time although it may take several more hours for them to taper off appreciably.

Cloud cover may linger along the TN border tonight in NW flow, though moisture appears too shallow to warrant PoP mention. Otherwise, generally clear skies tonight. Temperatures will fall 5-10 below normal for morning mins. Most of the mountains will see mins in the lower teens. The wind will result in wind chills below -5F across a good portion of Avery County, sufficient to issue a Cold Weather Advisory. Sub-zero wind chills are expected in very high elevations of other counties, but area hitting -5F is too small to justify a product. We will maintain an HWO mention thereof in those counties.

Key message 2. Elevated fire weather conditions possible Tuesday afternoon in dry post-frontal airmass.

Breezy northwest winds will persist Tuesday. Temperatures will top out in the 30s across much of the mountains, and below freezing in northern and higher-elevation locations. RH will be kept above 30 percent on account of the cold. Outside the mountains, though gusts are expected to be below the level which would warrant fire headlines, diurnal warming will bring max temps into the 40s, while dewpoints remain largely in the single digits. Thus RH easily should fall below 30 percent, a critical value for fire weather. Land managers in NC and SC have opted to wait and see how fuel moistures respond to the wind and drying today before providing input into decisions regarding fire weather alerts.

SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/

As of 1115 AM EST Monday...

Key Message #1: Dry conditions Wednesday and Thursday with temperatures trending back above climo.

The cold air will retreat from the area by the middle of the week. Highs will quickly moderate to near climo on Wednesday and then to as much as 5 degrees above climo outside the mountains on Thursday. No rainfall is expected during this period.

LONG TERM /THURSDAY NIGHT THROUGH MONDAY/

As of 1125 AM EST Monday...

Key Message #1: Dry with above climo temperatures Friday.

A cold front will stall south of the area on Friday. Conditions will remain dry and a few degrees warmer than climo.

Key Message #2: A southern stream low pressure system could bring rain to the region on Friday night and Saturday.

A fast moving southern stream system will race across the southern states on Friday night and Saturday. This will bring some organized rainfall to the area, with even the mountains too warm for any wintry precipitation. Conditions should be dry and slightly above climo temps on Sunday.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

At KCLT and elsewhere: Breezy VFR conditions expected to persist through the TAF period. With a cold front now analyzed over the coastal plain of the Carolinas, well east of the terminal forecast area, expect NW winds overnight. Sporadic gusts up to 20kts may continue for a few more hours at the non-mountain sites, but should give way to a steady 5-10kt NW wind during the overnight hours. At KAVL, frequent ~25kt gusts will likely persist through much of the overnight period. Tuesday, lower-end gusts of 15-20kts are still expected as NW flow continues. SKC expected through the period, with the exception of KAVL, which could briefly see FEW stratocu for a couple hours leading up to daybreak.

Outlook: Dry and VFR conditions linger through Friday.

FIRE WEATHER

Following collaboration with the Peachtree City NWS Office and the Georgia Forestry Commission, we have issued a Fire Weather Watch for all six of our counties in northeast Georgia, for Tuesday afternoon.

Afternoon relative humidity values are expected to drop as low as 20%, with some isolated locations even falling into the teens. Winds may gust to 20-25mph for much of the day. Land managers have expressed concern that excessively dry fuels and another day of critical relative humidity will coincide to produce a favorable fire environment. So, despite forecast winds not quite reaching strict Red Flag conditions, criteria have been waived in support of land manager activities.

Further coordination with GFC and NWS FFC will take place overnight, to determine final issuance of either a Fire Danger Statement or a Red Flag Warning, depending on forecast trends and operational needs at that time.

GSP WATCHES/WARNINGS/ADVISORIES

GA...Fire Weather Watch from Tuesday afternoon through Tuesday evening for GAZ010-017-018-026-028-029. NC...High Wind Warning until 7 AM EST Tuesday for NCZ033. Cold Weather Advisory from 10 PM this evening to 10 AM EST Tuesday for NCZ033. Wind Advisory until 7 AM EST Tuesday for NCZ049-050-501-503- 505. SC...None.