Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 200601
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
201 AM EDT Wed Jun 20 2018

.SYNOPSIS...
Stalled front overhead will provide showers and storms through
Wednesday. Unsettled weather remains through the weekend as the
front remains in the vicinity and a low pressure approaches.

&&

.NEAR TERM /THROUGH TODAY/...
As of 925 PM Tuesday...

Adjusted PoPs and thunder according to latest radar imagery.
Expect most of convection to decrease in intensity and coverage
as temperatures cool down after sunset. Guidance shows areas of
fog development tonight. Suspect that areas that received
afternoon rainfall will try to fog under weak BL winds. However,
it will be a battle between cloud cover and fog development.
Rest of forecast remains on track.

As of 210 PM Tuesday...

Not a whole lot of changes in the overall forecast from this
morning. Cold front is currently draped across Northern West
Virginia and will continue to sag southward this afternoon and
evening. However, this boundary eventually stalls this evening
and retreats back to the north. Expecting on going numerous
thunderstorms out ahead of this front, with activity growing as
we near max heating for the day. Although wind shear is weak,
instability is quite high with a very moist atmosphere in place.
PWAT values close to 2 inches, short corfidi vectors support
training cells and deep warm cloud layer will also elevate the
flash flood threat. However, very tough to pin point an exact
location and a watch will not be issued, but localized flash
flood event is very possible.

Severe potential is modest this afternoon and evening. Biggest
threat will be due to wet microbursts. SPC meso analysis
indicates DCAPE values across our Central CWA above 1000...with
PWATs as high as they are, would not be surprised to see a few wet
microbursts from precip loading. However, potential severe
storms should be isolated and probability for any convective
watch appears quite low.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
As of 300 PM Tuesday...

The main focus for the short term is nearly stacked surface and
upper level lows gradually moving through the Missouri and
Mississippi River valleys mid week, and then into the lower Ohio
River Valley by Friday morning. This system will eventually pick
up a frontal boundary that models show stalled just to our south
and push it north as a warm front Thursday night and Friday. The
surface low should then move into the Great Lakes Friday night
into Saturday as the upper level low opens into a trough. This
will drive a cold front through Saturday. With lots of clouds
around through the short term, temperatures will not be as warm
as earlier in the week, but the very humid air remains and will
lead to areas of showers and thunderstorms with heavy rain each
day. Flooding concerns will be on the increase, especially if
the same areas are hit multiple days, or if multiple storms
cross the same basins in a shorter period of time.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 300 PM Tuesday...

One cold front should be headed east away from us to start the
period, with a secondary, weaker front sinking toward us from
the Great Lakes. This second front will usher in high pressure
with drier air late Monday into Tuesday. Did keep some lingering
POPs area wide through Monday morning to account for timing
uncertainty, and then kept low end POPs across the far south
into Tuesday -- closer to the surface boundary. Used a
consensus blend for temperatures.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 155 AM Wednesday...

A frontal boundary will gradually return north of the area
through the predawn hours with just an isolated shra threat.
Areas of dense fog will develop across most of the river
valleys. This will affect most terminals with IFR or worse
conditions developing. KCKB may hold on to a low stratus deck,
resulting less of a vsby restriction.

Morning fog will dissipate by 13Z...perhaps followed by a brief
period of MVFR stratus at northern terminals.

The boundary will return south as a cold front this afternoon
with shra/tsra developing along it. Given the confidence of this
occurring, I have opted for a period of predominate TSRA at the
terminals based on POP timing. Brief IFR or worse vsby
certainly possible in convection, but capping no lower than
MVFR vsby at this distance.

Convection will wane this evening with areas of dense fog
developing.

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


FORECAST CONFIDENCE: Medium

ALTERNATE SCENARIOS: Dense fog formation could not materialize
under cloudy skies. Timing of convection could vary from
forecast an hour or tow.


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 06/20/18
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  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    L    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  H    M    L    L    L    L    L    M    H    H    H    H
PKB CONSISTENCY  M    M    M    H    H    M    H    L    H    M    H    H
CKB CONSISTENCY  M    M    M    M    H    H    H    H    H    H    M    H

AFTER 06Z THURSDAY...
Brief IFR conditions expected in afternoon thunderstorms
throughout the week.

&&

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

&&

$$
SYNOPSIS...MZ/MPK
NEAR TERM...ARJ/MPK
SHORT TERM...MZ
LONG TERM...MZ
AVIATION...30



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