Area Forecast Discussion
Issued by NWS Charleston, WV-- Remove Highlighting --
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FXUS61 KRLX 281034
Area Forecast Discussion
National Weather Service Charleston WV
634 AM EDT WED SEP 28 2016
A large upper level low brings unsettled weather into the area
this afternoon and tonight. This system will affect the area
through the work week, before pulling out over the weekend.
.NEAR TERM /THROUGH TONIGHT/...
As of 400 AM Wednesday...
Upper low across the Great Lakes region...will gradually dig
south into the midwest today. Models have slowed entry of
precipitation/frontal boundary from the west until later this
evening...and have adjusted pops accordingly. Greatest slug of
moisture/precipitation still looks to be just to the east of the
cwa...with strong southerly winds and high moisture transport into
that area...and models in good agreement with keeping axis of higher
moisture out of the cwa. Moist southeasterly flow...will lead to an
increase in cloud cover across the mountains later
today...particularly across eastern slopes...along with the
possibility for -shra. Otherwise...much of the CWA will remain dry
and sunny through at least the afternoon hours...with showers
increasing in coverage this evening with approach of frontal
boundary. Expecting another afternoon of warm temperatures...and
good mixing...with gusty winds in the afternoon...and relative
humidities dipping into the 30 percent range...particularly across
the WV lowlands.
For tonight...expecting showery conditions...with bulk of activity
across western zones associated with frontal boundary.
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
As of 400 AM Wednesday...
Large, anomalously deep upper level low meanders in a rex block
about central Kentucky Thursday through Friday, before slowly
drifting northward into Michigan by Sunday morning, as the rex
block breaks down.
This positioning keeps the main Atlantic moisture feed from the
southeast, northeast of the forecast area for the most part.
However, The NAM12 suggests a second band of heavy rainfall
farther west, right over the forecast area, Thursday afternoon and
night, when the upper low is at its southwestern-most point, just
east of Nashville.
A good chance for showers continues on Friday, with the upper low
close by to the west. The chance for showers should diminish from
south to north Friday night, as the upper low drifts northward.
Showers do remain possible west, over the middle Ohio Valley, on
Saturday, closer to the northward tracking low. Saturday night
should turn out mainly dry as the upper low moves up into
Michigan, far enough to the north and west to allow the dry slot
to envelop the entire forecast area.
Instability due to diurnal heating below the low upper level
heights and temperatures gives rise to the chance for afternoon
and evening thunderstorms Thursday and Friday. These low values
increase enough to leave the chance for late day thunder out on
Saturday, with the upper low drifting away from the area.
Not much change needed to temperatures in light of the latest
guidance. Highs will be lowest west, closer to the upper level
low. Thursday and Thursday night will also be coolest near the tug
fork, when the upper low is farthest south. Overall, temperatures
run near to a little below normal by day and near to a little
above normal by night, for diurnal ranges a bit on the small side.
.LONG TERM /SUNDAY THROUGH TUESDAY/...
As of 330 PM Tuesday...
The pesky upper low will gradually track north over the
weekend...with less of an influence on the sensible weather as the
days progress. This will result in a dry pattern taking hold again
with temperatures moderating to normal and eventually above
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --As of 630 AM Wednesday...
Patchy river valley fog this morning will burn off after
13Z-14Z...for a return of VFR conditions area wide. South to
southeasterly winds today...with occasional gusts in the teens.
Clouds will increase during the period...but should remain mostly
VFR...with the exception of along the eastern slopes of the higher
terrain...where the possibility exists for MVFR cigs and vsbys to
develop in moist southeasterly flow...generally after
00Z...impacting sites such as kbkw. -shra will move into the area
generally after 23Z...with brief mvfr conditions possible.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...
FORECAST CONFIDENCE: Medium.
ALTERNATE SCENARIOS: Development of mvfr cigs across eastern
slopes and resulting impacts at KBKW may differ from forecast.
Timing of showers this afternoon and evening and resulting
restrictions may vary from forecast.
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 10 11 12 13 14 15 16 17 18 19 20 21
EDT 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY M L L M H H H H H H H M
HTS CONSISTENCY H H H H H H H H H H H M
BKW CONSISTENCY H H H H H H H H H H H M
EKN CONSISTENCY L L L M H H H H H H H M
PKB CONSISTENCY H H H H H H H H H H H M
CKB CONSISTENCY H H H H H H H H H H H M
AFTER 12Z THURSDAY...
Areas of ifr possible in showers and thunderstorms through
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