Area Forecast Discussion
Issued by NWS Charleston, WV-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KRLX 261803
Area Forecast Discussion
National Weather Service Charleston WV
203 PM EDT TUE JUL 26 2016
A weak east to west frontal boundary continues across northern
portions of area. Next system late in the week.
.NEAR TERM /THROUGH TONIGHT/...
1030 AM update. Adjusted placement of max pops to focus along
front in the north early this afternoon...then shift southward
later this afternoon into central and southern areas prior to
significant decrease with loss of heating this evening.
Previous discussion...A weak quasi stationary front remains just
northwest of the area as seen in the sfc obs maps. The HRRR and
RAP models bring PCPN during the afternoon hours when the heat is
at its peak. Diurnal heating will combined with abundant moisture
to produce showers or storms during the afternoon hours. A tongue
of moisture, evident in precipitable water around 2 inches
continues in place. This can support isolated heavy downpours
Went with the National blend of models for temperatures through
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
Models in decent agreement with a weak wave combining with daytime
heating to pop some showers and thunderstorms on Wednesday. Have
generally south to north POP gradient, with the highest POPs across
southern CWA gradually decreasing to the north.
The models are having a bit more trouble agreeing on a more
significant surface low for Thursday into Friday. NAM and GFS show
this wave riding along a warm front and crossing CWA Thursday into
Thursday night... with the GFS a touch faster than the NAM. The
ECMWF is farther NW with the surface low, and 12 to 18 hours slower.
At any rate, with the warm front lifting through the region went
with likely POPs Thursday. Precipitable water values look to be 2+
inches with this wave, so will have to keep a close eye on rainfall
amounts, especially if the warm front is slow moving or becomes
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
Used a blend of the ECENS mean...NAEFS mean...AND GEFS mean.
Weighted a bit more toward the ECENS mean than the others. This
would leave the area in the warm sector with plenty of moisture Saturday.
A cold front would then push into the area Sunday. Still
questionable if this front would push south of the area or not for
early next week.
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --18Z Tuesday thru 18Z Wednesday...
Nearly stationary east to west weak front across far northern
portions of area will continue thru period.
Thru 02z...Outside of convection...SCT-BKN 2000-3000 feet agl
becoming mainly VFR ceilings 3500-5000 feet by 20z. Increasing
showers and tstms mainly across southeast Ohio and northern WV
this afternoon...vicinity of the nearly stationary weak front. SCT
showers and tstms central and south.
After 02Z...most convection decreases with loss of heating. Generally
SCT-BKN 4000-8000 feet AGL with widely SCT showers mainly in the
north. 08z-12z MVFR river valley fog...except lower in the north
if earlier rains fall.
After 13z Wednesday...4000-6000 feet AGL with widely SCT showers
and tstms developing by 18z.
Winds this period nearly calm by night...light and variable by
CONFIDENCE AND ALTERNATE SCENARIOS...
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...
FORECAST CONFIDENCE: Medium.
ALTERNATE SCENARIOS: A shower or thunderstorm could directly affect
any TAF site Tuesday afternoon. Timing of Fog formation and
intensity may vary tonight depending on where it rains.
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.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
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 18Z WEDNESDAY...
Brief IFR conditions possible in thunderstorms every afternoon
and evening. Early morning IFR fog possible into mid week
depending, in part, on occurrence of showers or thunderstorms the
previous afternoon or night.
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