-- Discussion containing changed information from previous version are highlighted. --
195
FXUS61 KRLX 180632
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
232 AM EDT Tue Jul 18 2017

.SYNOPSIS...
Increasingly hot and humid pattern with scattered mountain
showers/storms through mid week. Storm chances increase with
northwest flow Friday into the weekend.

&&

.NEAR TERM /THROUGH TODAY/...
As of 955 PM Monday...

Forecast remains on track, no changes needed at this time.

As of 755 PM Monday...

Convection is beginning to diminish in OH and the northern
mountains of WV as instability wanes. Another quiet, albeit
humid, night in store with a warm and sticky day expected Tuesday.
Calm to very light surface winds under clear skies will once
again promote dense fog development in river valleys overnight.
Stuck closer to a persistence forecast to handle morning fog
across the area. The frontal boundary across southern OH
shouldn`t make much headway into the CWA as it continues to
slowly wash out. Did not include PoPs for tomorrow afternoon
with this feature considering the limited moisture and an
absence of sufficient forcing along the boundary. Upper trough
continues slowly pushing east, finally making it over the
easternmost counties by tomorrow afternoon. Surface heating
along the mountain ridges will increase instability and the
presence of sufficient moisture will once again favor scattered
afternoon/evening thunder, much like we saw today. Storms will
diminish by late evening.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
-- Changed Discussion --
As of 215 AM Tuesday...

Getting decent run to run consistency in the operational models
as the flow aloft gradually turns northwesterly in response to
the building ridge over the lower to middle Mississippi Valley.
As it does so, convection will be relegated north and west of
the CWA. Position of the associated warm front will be crucial
in the track of developing complexes as they encroach the
northern zones late in the short term. Remaining hot and humid
with dewpoints back over the 70F mark in lowland areas.
-- End Changed Discussion --

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
-- Changed Discussion --
As of 215 AM Tuesday...

The operational long term suffer from diverging solutions, but
a common theme on the front end is the increase in convective
activity. GFS will hold onto a more zonal pattern aloft while
the old 12Z run of the Euro develops an open wave aloft and
subsequent frontal system that will provide a distinct change in
airmass for the end of the long term. Lower confidence in the
POPs beyond Sunday as the blends keep the chances up but bring
in cooler air for the beginning of next week.
-- End Changed Discussion --

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
06Z Tuesday thru 06Z Wednesday...
As of 140 AM Tuesday...

Upper high pressure continues to build over the area from the
west today, and the weak upper trough slowly shifts east of the
WV mountains. While a weak surface boundary will still reside
over southeast OH today, the rising heights and warming aloft
will bring less afternoon convection for that area. The best
chance for afternoon convection will be over the northern
mountains of WV where a more moist low level upslope south
southeast flow combines with the weak upper trough. Nonetheless,
looks like widely scattered to scattered at best. Elsewhere, no
convection expected.

Overnight and Wednesday...
Expect another predawn development of IFR river valley fog
across the area, affecting most TAF sites again, except BKW,
between 09Z and 12Z. Thereafter, mainly SCT afternoon cu AOA
5000-7000 feet AGL, except ceilings 4000-6000 feet with
scattered afternoon storms mostly over northern WV mountains.
Near calm winds overnight becoming light westerly west of the
mountains, and light south winds east of the mountains later
Wednesday morning.

Wednesday night...
Any afternoon convection and daytime cu rapidly decrease with
loss of heating this evening. Any redevelopment of fog will be
after 06Z Wednesday. Near calm winds again.




FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY...

FORECAST CONFIDENCE: Medium for fog overnight. High for
remainder of the forecast.

ALTERNATE SCENARIOS: Fog timing and extent will likely vary.
May need to add VCTS for KEKN/KBKW tomorrow afternoon.

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                              TUE 07/18/17
UTC 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
EDT 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
CRW CONSISTENCY  M    M    L    L    L    M    M    H    H    H    H    M
HTS CONSISTENCY  H    M    L    L    M    M    M    H    H    H    H    M
BKW CONSISTENCY  H    H    H    H    H    M    M    H    H    H    H    M
EKN CONSISTENCY  M    M    L    L    L    L    L    M    H    H    H    M
PKB CONSISTENCY  M    M    M    L    L    L    L    M    H    H    H    M
CKB CONSISTENCY  H    M    M    M    L    L    M    H    H    H    H    M

AFTER 06Z WEDNESDAY...
Dense valley fog is possible Wednesday morning.

&&

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

&&

$$
SYNOPSIS...TRM/JMV/MZ/DTC
NEAR TERM...DTC
SHORT TERM...26
LONG TERM...26
AVIATION...JMV