607 
FXUS61 KRLX 260839
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
439 AM EDT Sat May 26 2018

.SYNOPSIS...
Strong upper level trough crosses today into Sunday. Dry with 
high pressure for Memorial Day. Unsettled weather should return 
by mid week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 255 AM Saturday...

Upper trough approaches the region from the west today. Expect
an increase in showers and thunderstorms through the day as low
level moisture increases and heights drop with the approaching
trough. Instability is looking fairly weak today, with maybe
some area topping out with about 800 J/Kg of CAPE. PWATs are
slightly anomalous over the region, and with low FFG values
across the Northern Forecast Area, we will have to watch for
isolated water issues today and tonight. 

Generally, this system should have minimal impacts to the area,
but cell movement will be quite slow with the weak winds aloft.
Areal coverage of any one shower or storm will be quite small 
though, but where they do hit, short bursts of high rainfall 
rates have the potential to cause flash flooding in the lower
FFG areas.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 420 AM Saturday...

Models show an upper level wave in H500 vorticity charts passing
slowly south Sunday night into Monday. Abundant moisture will 
continue over the area under generally weak flow. The 
combination of parameters, together with the afternoon heating 
will promote shower and storm development more numerous during 
the afternoon and evening hours. There should be a lull in pcpn 
activity Monday night as a drier airmass moves over. Therefore, 
coded chance PoPs with thunder for these conditions during the 
afternoon and evening hours. Went with the blend of all models 
for temperatures through the period. 

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 420 AM Saturday...

Bufkit soundings show a saturated column with limited bouyancy 
and about 20 knots of deep layered shear for Tuesday. Kept PoPs 
to the extreme southern portions of our CWA for now, and dry 
conditions across the northern two thirds of the area. These 
conditions arise as a back door cold front approaches from the 
northeast, while the remnants of what became the sub-tropical 
storm Alberto begin to move north out of the Gulf of Mexico.

Consistency among run-to-run model provides some confidence that
if the remnants of Alberto track our way, it will spread an area
of stratiform rainfall with embedded showers due to limited
instability despite high moisture presence Wednesday through 
Thursday. Otherwise, tropical moisture could move south and east
of the area. Continued with showers and storms possible Friday 
with an upper level system somewhere in the Great Lakes region.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
As of 145 AM Saturday...

Possible IFR fog tonight at EKN and PKB and possible MVFR fog
elsewhere except BKW. EKN is most likely area to see LIFR fog,
due to a few light showers that have primed the ground with
added moisture. At PKB, confidence is much lower and low level
flow may be just strong enough to keep visibility in the MVFR
range. 

A strong upper level disturbance, to more numerous showers and 
thunderstorms today. Any showers or storms could bring brief IFR
conditions if there were to pass overhead, but confidence is too
low at this time to say which sites may be impacted.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY...
     
FORECAST CONFIDENCE: Medium

ALTERNATE SCENARIOS: IFR fog overnight and early Saturday 
morning may not develop at PKB and timing of onset may differ at
EKN. May need to add TSRA and flight restrictions for numerous 
cells on Saturday.

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                                                            FRI 05/25/18
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    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    L
EKN CONSISTENCY  H    H    H    H    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 06Z SUNDAY...
No widespread IFR expected.

&&

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

&&

$$
SYNOPSIS...ARJ/MPK
NEAR TERM...MPK
SHORT TERM...ARJ
LONG TERM...ARJ
AVIATION...MPK