Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 200013
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
813 PM EDT Tue Sep 19 2017

.SYNOPSIS...
Weak upper level impulse brings some showers, perhaps an
afternoon thunderstorm, through Wednesday. Weak high pressure
builds late week through the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 740 PM Tuesday...

Updated to increase pops for a few hours this evening over
northeast KY and southeast OH per radar trends. These should
dissipate for the most part later this evening as the airmass
stabilizes.

As of 220 PM Tuesday...

A weak upper level short wave trough moving across the area
this afternoon and Wednesday, may end the broken record of
overnight and early morning dense valley fog, although still
have some fog in the forecast.

The short wave, and the tail end of a warm front lifting through
the Great Lakes, was producing a patchwork of showers in a band
from Ohio southward, through eastern KY and central TN. There
were also thunderstorms included in the band farther south, in
KY and TN, on account of less cloud, and hence more heating,
ahead of it there. That trend will continue eastward, until
sundown reduces the thunder chance.

Continue to carry a slight chance for showers tonight as the
short wave trough moves over the area, with coverage increasing
a bit Wednesday afternoon per diurnal heating, and the feature
moving east. However, greater instability on some clearing
west, and higher dew points there, will tend to equalize the
chance for thunder west versus east.

Temperatures and dew points looked good in light of the latest
guidance, with clouds resulting in not quite as cool a night
tonight.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 225 PM Tuesday...

Still the possibility of isold showers and thunderstorms Thursday
and Friday as weak impulses traverse the region. Temperatures will
continue to run above normal for this time of year, with foggy
mornings continuing.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 225 PM Tuesday...

Upper ridging will strengthen across the eastern U.S. during the
period, with continued hot/above normal temperature conditions.
Could be an isolated storm or shower over the higher terrain at
times, but overall, period looks to be relatively dry, with light
surface winds, and a continuation of foggy conditions in river
valleys. A cold front will arrive by the middle of next week/end of
the extended period, providing a greater chance for showers and
storms.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
00Z Wednesday thru 00Z THursday...
As of 745 PM Tuesday...

Til 03Z...
Brief uptick in convection over northeast KY at 23Z should wane
quickly by 03Z as the airmass stabilizes with loss of heating.
Elsewhere, VFR SCT-BKN clouds AOA 4000 feet AGL.

After 03Z...
A weak upper level disturbance may break up the early morning river
and valley fog somewhat, as it brings altocu and some stratocu,
along with an isolated shower late tonight. Have MVFR river and
valley fog forecast after 06Z affecting the major TAF sites
except BKW, and IFR in fog after 09Z except BKW. The chance for
showers late tonight is too small for a specific TAF mention
this period.

Showers and storms increase a bit across the area on Wednesday,
especially in the afternoon with heating under the very slow
moving upper disturbance.

Light and variable to calm flow will become light west aloft
during Wednesday.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY...

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Timing and density of fog may vary
overnight into Wednesday morning.

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                                                            WED 09/20/17
UTC 1HRLY       00   01   02   03   04   05   06   07   08   09   10   11
EDT 1HRLY       20   21   22   23   00   01   02   03   04   05   06   07
CRW CONSISTENCY  H    H    H    H    L    L    M    M    M    M    M    L
HTS CONSISTENCY  H    H    H    H    H    L    L    L    L    M    M    L
BKW CONSISTENCY  H    H    H    H    H    H    H    H    M    M    M    L
EKN CONSISTENCY  H    H    H    H    M    M    M    M    L    L    L    M
PKB CONSISTENCY  H    H    H    H    L    L    M    M    M    M    M    L
CKB CONSISTENCY  H    H    H    H    H    H    M    M    M    L    L    M

AFTER 00Z THURSDAY...
IFR in valley fog possible each morning through the weekend.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.

&&

$$
SYNOPSIS...ARJ/TRM/JMV
NEAR TERM...TRM/JMV
SHORT TERM...SL
LONG TERM...SL
AVIATION...JMV



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