Area Forecast Discussion
Issued by NWS Charleston, WV

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KRLX 220006 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 706 PM EST Thu Feb 21 2019 .SYNOPSIS... High pressure in control through early tonight. Several systems will bring unsettled weather mainly across the south tonight into Friday night and then spreading north through the weekend. && .NEAR TERM /THROUGH FRIDAY/... As of 705 PM Thursday... Sped up the POPs slightly across the west. Have echoes aloft, most of it likely not reaching the ground yet, but brought low end POPs in to cover just in case. No major changes to the advisory area in the mountains for the freezing rain. As of 209 PM Thursday... Surface high pressure system remains on control of our weather into early tonight. A series of shortwaves then should result in increasing clouds as well as precipitation moving back into the region from the southwest tonight. Based on latest model guidance, have increased POPs to likely tonight across southwest VA as well as far southern WV and the WV mountains. The precipitation should fall as rain in most of these locations. However, freezing rain is possible across the highest elevations of the northern mountains where up to 0.10 inches of ice is possible. After consultation with our neighbors, have gone ahead and issued a winter weather advisory. Models suggest northern edge of precipitation should move back to the south during the day. Because of consistency between the models, have gone ahead with this thinking. Could see 0.25 to 0.50 inches of rain across our far southern counties tonight through Friday. Previous temperature forecast generally looks good. Have only made minor tweaks to reflect latest guidance. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... As of 310 PM Thursday... Scattered showers linger as a remnant frontal boundary stalls Friday evening across the southern third of the area. Meanwhile, a deeply amplified trough ejects from the Rockies during this time, producing a variety of potential hazards as it approaches and crosses our area. A light glaze along the highest ridges and peaks of the north/central WV mountains is possible early Saturday as precipitation moves into the area, but impacts would be minimal with quickly warming temperatures. The trough of interest rotates negatively into the Plains Saturday, strengthening southwest flow to 50 kts at 850 mb, lifting the remnant boundary North as a warm front in the Ohio Valley. As a result, moisture increases to 1.3"+ PWAT area-wide by Saturday afternoon. This leaves ample opportunity for moderate to heavy rainfall basically everywhere Saturday into Saturday night. While many long-range models have consistently placed an axis of heavy rainfall of 1-2" near and South of the 64 corridor, the NAM and SREF have trended and shifted the corridor further North into the Middle Ohio Valley and into SE Ohio. Most of these lowland areas are already saturated, and have streams already running high, and the mountains have considerable liquid captured in snowpack, so flood vulnerability exists basically everywhere. The greatest threat would therefore exist where any axis of heavy precipitation sets up. Fortunately, convective rainfall looks unlikely on Saturday with a strong low-level temperature inversion keeping things pretty well capped in this warm frontal scenario. Some elevated instability exists in the OH/KY/WV Tri-state region Saturday afternoon, but currently not enough confidence to include thunder in that portion of the forecast. Saturday night, thunderstorm threat increases in spite of fairly limited instability, and is chiefly tied to the cold front itself, where frontal lift can tap into modest elevated CAPE on the order of 500 J/KG CAPE. Very high shear on the order of 80+ kts 0-6km means that one or more potent lines of thunderstorms will form ahead of the front packing isolated damaging wind gusts. Storms will tend to be much stronger toward the West over parts of the lower Ohio and Tennessee Valleys where stronger daytime instability exists, however those storms will likely spill into Appalachia as they weaken with the setting sun thanks to aforementioned strong low- and mid- level flow. So, strong gusts, mainly sub-severe, are likely area-wide, but saturated grounds mean trees and power lines can come down with wind gusts well below severe criteria. Models place the cold front near the Ohio River during the pre- dawn hours of Sunday and then quickly shoves it across the WV mountains by late morning. Moisture aloft quickly diminishes behind the front, ending the flood and thunderstorm threat. Low- to mid-level moisture remains in the cold-advective scheme, so do expect area-wide cloud cover to remain through the period with lingering drizzle/freezing drizzle in the mountains tapering off Sunday evening. Strong winds do linger however through Sunday as the upper level trough rotates up and out toward the northeast, with gusts 30-40+ kts possible everywhere. && .LONG TERM /MONDAY THROUGH THURSDAY/... As of 315 PM Thursday... Zonal flow takes hold across much of the CONUS with the departure of the short- term period`s trough, which makes for a relatively quiet and much-needed dry period, albeit with a degree of temperature uncertainty given weak forcing. The GFS tends to keep the region on the warm side and the ECMWF on the cool side. Long- range models bring in the next system by mid-week. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... As of 630 PM Thursday... The forecast starts off with VFR dominating until a frontal band to our south spreads precipitation northward into the southern half of the region. Clouds will spread lower all around and be aggressively lower in the southern portions of the area. Rain showers will spread from South to North as well bringing MVFR ceilings to some terminals. BKW will encounter rain first, just before midnight, and continue for the duration of this forecast period. There will be brief periods of rain showers with MVFR ceilings at HTS/CRW around midnight for a few hours. BKW will also have brief periods of IFR visibility in any heavier rain showers especially early in the morning. Winds will be northerly and light overnight and shift to the north- northeast by early morning. One thing worth mentioning, if any rain does make it into the eastern mountains where temperatures are below freezing (far north) there can be patchy freezing rain across the highest elevations early in the morning. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY... FORECAST CONFIDENCE: High. ALTERNATE SCENARIOS: None. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE FRI UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EST 1HRLY 19 20 21 22 23 00 01 02 03 04 05 06 CRW CONSISTENCY H H H H H H H H H M H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H M M M M L M M L EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 00Z SATURDAY... IFR possible in rain beginning Friday night and continuing through Saturday night. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Winter Weather Advisory until 10 AM EST Friday for WVZ523-526. Flood Watch from 1 AM EST Friday through Sunday morning for WVZ005>007-013>015-024>027-033-034-515>520. OH...Flood Watch from 1 AM EST Friday through Sunday morning for OHZ083-086-087. KY...Flood Watch from 1 AM EST Friday through Sunday morning for KYZ101>103-105. VA...Flood Watch from 1 AM EST Friday through Sunday morning for VAZ003-004. && $$ SYNOPSIS...JSH/MC NEAR TERM...JSH/26 SHORT TERM...MC LONG TERM...MC AVIATION...JZ is the U.S. government's official web portal to all federal, state and local government web resources and services.