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
000
FXUS61 KRLX 251035
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
635 AM EDT WED MAY 25 2016

.SYNOPSIS...
Weak disturbances within ridge aloft today into Thursday. Ridge
stronger Friday/Saturday.  Southeast flow may eventually increase
shower coverage Sunday into Monday...especially over mountains.

&&

.NEAR TERM /THROUGH TONIGHT/...
630 AM Update...
No changes this morning. Have cirrus advection aloft ahead of the
first upper level disturbance aloft to the southwest.

Previous Discussion...
Seeing increases in dewpoints this today...topping the 60s in the
western zones in the transition to a warmer and higher moisture
content airmass. Now under the influence of weak ridging aloft...a
couple of weak waves within the flow suggests convection today. But
the upper level feature does not have much in the way of surface
forcing...and mid and upper level moisture are expected to
overspread the CWA simultaneously. These factors will limit the
coverage today...with an early peak to the activity to the western
zones because of the dampening of the upper level wave. There will
be some CAPE out there...but little low level flow and the
aforementioned clouds limit thunder activity.

NAM indicates a few more weak disturbances this evening and
tonight...so largely held low chances through the near term. POPS
come up to chance late tonight with small scale frontogenesis
developing over the northeastern zones.

Held the western zones back a couple of degrees on the high
temperatures today...and went slightly higher than guidance tonight
on overnight lows.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
Certainly hard to grasp any significant feature and run with it.
Will have to wait until these time periods get into the near
term...and try to get more specific.  So...as of now...hourly pops
certainly can not get out of the chance range.

Weak mid/upper level disturbances linger Thursday...before 500 mb
heights increase slightly Thursday night into Friday.  Most of the
moisture plume in the lower Ohio Valley should remain to our west
through Saturday.

Yet...the precipitable water still jump back to around 1.25 inches
Thursday and Friday.  Then the southeast flow actually brings drier
air aloft on Saturday...lowering the precipitable water.

A weak flow dominates with afternoon and evening instability...so
reserved the mention of thunder for the afternoon and evening hours.
In the weak flow...tried to have the higher chance pops on Thursday
over the mountain counties. On Friday afternoon and evening...some
hints on both the 00z gfs and 00z nam that if some convective cells
form the southern mountains...it may try to drift north...off the
mountains into the southern lowlands.

Figuring a breeze stirs overnight Thursday night in southeast
Ohio...so have minimum temperatures a bit higher there. Otherwise...
in the light winds...have minimum temperatures a bit below guidance
in the hollers further south and east...but leftover clouds could
hurt that thinking.

We still have some 90 degree temperatures on Saturday...in the
southern river valleys...as that mentioned drying aloft occurs.  Of
course...most official temperature sites in the lowlands have not
reached 90 degrees yet this year.

Due to a weak southeast flow...maximum temperatures along the
eastern slopes...including the southern plateau around
Beckley...are not forecast to be higher Saturday compared to Friday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
Summer like weather is still on tap for the Memorial Day weekend.
Upper level ridging holds into Sunday before drifting off the east
coast. Have just the slight chance for the late day shower or
thunderstorm Saturday, and then a better chance on Sunday as the
ridge begins to drift east.

As the ridge drift offshore, a weak upper level over the Carolinas
this weekend will start meandering to the northwest. This may
actually bring a developing tropical or subtropical feature
inland. Models generally differ with the track and lose the system
under the light upper level flow. Suffice it to say for now that
the forecast gets a bit dirtier early next week, with a better
chance for late day showers and thunderstorms and a non-
negligible chance at night.

Either way, the very warm and humid air remains in place through
the period, and even beyond. The midnight shift coded 90 for
Charleston for Saturday, which may be a touch aggressive, but the
pattern and guidance are close enough to give it a chance.
Overall, not much disparity between ongoing temperatures and
guidance.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
VFR ceilings and visibilities prevail today despite the passage of
a few weak upper level disturbances today and tonight. These may
kick off showers...and in the isolated instance thunder...but
chances are too low to warrant prevailing or TEMPO conditions in
the TAF. Some low level VFR cumulus could form after 16Z...but
expect mid and upper level moisture to increase through the day.
This moisture will become the prevailing ceiling...especially in
the evening and overnight. Clouds tonight will keep fog from
forming.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...

FORECAST CONFIDENCE: High.

ALTERNATE SCENARIOS: Brief MVFR in a shower is possible.

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    M    M    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  L    L    M    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 12Z THURSDAY...
No widespread IFR conditions expected.

&&

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

&&

$$
SYNOPSIS...KTB/26
NEAR TERM...26
SHORT TERM...KTB
LONG TERM...TRM
AVIATION...26



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