Area Forecast Discussion
Issued by NWS Greer, SC

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000 FXUS62 KGSP 241456 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 1056 AM EDT TUE MAY 24 2016 .SYNOPSIS... High pressure will prevail over the Southeast most of this week. A moist southerly flow will develop by tomorrow, which will lead to warmer temperatures and mainly afternoon chances of showers and thunderstorms each day through Friday. && .NEAR TERM /THROUGH TONIGHT/... As of 1045 AM Tuesday: No significant changes to the forecast for the morning update. Main grid adjustments have been to reduce sky cover through the day and adjust T/Td/winds based on recent obs trends as well as near-term guidance. Otherwise, upper ridging builds into the area today and tonight as surface high pressure moves east across the area. This results in a weak, but increasing southwesterly flow. Expect some ridge top cumulus to develop during the afternoon, with mostly sunny skies elsewhere. With thicknesses rising, highs today will top out near or a little above normal. Any ridge top cumulus will dissipate with loss of heating this evening. However, expect an increase in clouds across the mountains overnight as a weak short wave moves through the ridge and into the area. Forecast remains dry, with lows dropping to near or a couple of degrees above normal. Patchy fog will again be possible, but chance of widespread or dense fog is low. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 315 AM Tue: High pressure over the South Atlantic coast will bring south to southwest return flow into the area Wed and Thu. Diurnal instability will trend upward from day to day, driving diurnal showers and thunderstorms. Subsidence will keep the Piedmont sufficiently stable Wed, so PoPs are confined to the mountains then; they expand to about the I-85 corridor Thu. Minimal shear implies mainly disorganized pulse storms can be expected with localized downbursts being the main threat besides lightning. Temps will rise about a category above climo each day. && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 300 AM Tue: The late week pattern will be dominated by a broad upper ridge centered over the mid-Atlantic coast and sfc high pressure. This by itself would result in rather run-of-the-mill weather for late May, in which PoPs would be tied to diurnal instability and temps at or a little above climo. However, the proverbial fly in the ointment is what appears to be increasing consensus for a tropical low to move into the Carolinas over the weekend. Spread on the track thereof is still pretty wide overall, but the 00z GFS and EC both show landfall near the Grand Strand. They differ on its position thereafter. Winds do not appear to be of concern on land at this point, but the nature of moisture flux varies across the guidance spectrum, so it is difficult to say whether PoPs would be greatly increased or decreased by the presence of the system. It is difficult to make a model blend (for grid production purposes) that does not reflect any influence from it, though confidence on its track remains moderate at best. My preferred choice of action at this point is to reflect PoPs only slightly above climo, with mainly diurnal trends, but elevated sky cover and slightly cooler temps Sun-Mon. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... At KCLT and elsewhere: No changes to the KCLT TAF for the 15z AMD. Otherwise, just intermittent cirrus moving in through the rest of the period. Light NW or W wind becomes SW as mixing develops by noon. Winds become light and variable or calm this evening. Patchy fog cannot be ruled out overnight, but chance of restrictions is low. Outlook: Mainly VFR conditions will prevail through the week, but patchy morning fog chance continues at KAVL. Scattered afternoon SHRA/TSRA may return Wednesday, with daily coverage increasing Thursday and Friday. Confidence Table... 15-21Z 21-03Z 03-09Z 09-12Z KCLT High 100% High 100% High 100% High 100% KGSP High 100% High 100% High 100% High 100% KAVL High 100% High 100% High 100% High 100% KHKY High 100% High 100% High 100% High 100% KGMU High 100% High 100% High 100% High 100% KAND High 100% High 100% High 100% High 100% The percentage reflects the number of guidance members agreeing with the schedule TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables and ensemble forecasts are available at the following link: www.weather.gov/gsp/aviation && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...Wimberley NEAR TERM...RWH/TDP SHORT TERM...Wimberley LONG TERM...Wimberley AVIATION...RWH/TDP

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