Area Forecast Discussion
Issued by NWS Charleston, WV

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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
607
FXUS61 KRLX 270232
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
1032 PM EDT Wed Jul 26 2017

.SYNOPSIS...
Low pressure system brings rounds of showers and thunderstorms,
with heavy rain, Thursday through Friday. High pressure with
cooler and less humid air follows for the weekend into next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 1030 PM Wednesday...

No significant changes.

As of 8 PM Wednesday...

No significant changes.

As of 210 PM Wednesday...

Flat cu field mainly from I-77 to the east. Otherwise noted
some CI working in from the northwest. An upper level wave
sweeps south across the Great Lakes with mid level clouds
expected to spread across the forecast area across the forecast
area Thursday. Moisture in atmospheric column increases
significantly by Thursday afternoon as forecast area comes under
the influence of high PW plume. Think severe threat will be
somewhat diminished due to high precipitable water values.
Heavy downpours and gusty winds will be threat increasing from
west to east in the afternoon hours.

Latest model information has dipped most max temp values down a
degree or two across the board for Thursday. The solution
generally accepted since there will be more clouds than sun that
could offset any warm air advection.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 315 PM Wednesday...

General forecast pattern remains the same this period, although
there are still timing and tracking differences in the axis of
heaviest QPF with these features. Lead short wave out ahead of a
strong upper low dropping southeastward thru the Great Lakes
will drag a cold front eastward into the Ohio Valley Thursday. A
low pressure center will then form and ride up the front to our
west as the strong upper low drops southeastward thru the Great
Lakes later Thursday and Friday. With anonymously high PW`s AOA
2 inches feeding northeastward ahead of the front and good
dynamics, the result will be a large swath of heavy showers and
thunderstorms along and ahead of the low and slow moving cold
front.

While it appears the severe thunderstorm threat has been
reduced with all the expected clouds and less sheared
environment, the heavy rain potential continues to be a real
threat. Again, the axis of heaviest rains remain in question,
as the the models target different parts of the area. With this
uncertainty, will continue to highlight heavy rain potential in
the Hazardous Weather product Thursday and Friday.

Newer model runs show the upper low to be progressive enough for
things to clear out Saturday morning. A cool season like
Canadian high pressure system will build in behind the front
later Friday and gain real control Saturday. Look for an
abnormally cool and rainy Friday, and a cool but drier Saturday.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 335 PM Wednesday...

A tranquil period under a dry northwest flow aloft with
Canadian high pressure hanging around. There will be a slow
increase in high temperatures each day with abundant sunshine,
but it will be dry with still at or below normal temperatures.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
As of 8 PM Wednesday...

Fog overnight tonight will be limited to the valleys of
northeastern West Virginia, as a low pressure system approaching
from the west brings increasing cloud. Have IFR only in the
Tygart Valley and MVFR mist for CKB, PKB and possibly CRW /6SM
coded there/.

As the system moves in Thursday, the likelihood for showers and
thunderstorms increases. Clouds and the near widespread
coverage of the showers and thunderstorms limits the severe
risk, but thunderstorms could still produce strong wind gusts,
and any thunderstorm can bring IFR conditions in heavy
downpours.

Surface flow will generally be light south to southeast, while
light southwest flow aloft tonight becomes light west to
southwest for Thursday.

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

FORECAST CONFIDENCE: Medium to high.

ALTERNATE SCENARIOS: Formation and timing of fog could vary
overnight, and the dissipation of fog can vary by an hour or two
early Thursday morning. Timing of showers and thunderstorms,
and associated flight categories, could vary on Thursday, with
short term amendments likely needed.

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                                                            THU 07/27/17
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    H    H    H    H    H    H    H    L
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    L
BKW CONSISTENCY  H    H    H    H    H    H    M    H    H    M    M    L
EKN CONSISTENCY  H    H    H    M    M    M    M    M    M    L    L    L
PKB CONSISTENCY  H    H    H    H    H    H    H    M    M    M    M    L
CKB CONSISTENCY  H    H    H    H    H    H    H    H    M    M    M    L

AFTER 00Z FRIDAY...
Brief periods of IFR conditions with thunderstorms likely
Thursday night into Friday, perhaps more persistent in low
clouds Friday morning.

&&

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

&&

$$
SYNOPSIS...KMC/TRM/JMV
NEAR TERM...KMC/TRM
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...TRM



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.