FXUS61 KRLX 151840
AREA FORECAST DISCUSSION
National Weather Service Charleston WV
240 PM EDT Sat Jun 15 2019
Scattered thunderstorms and localized flash flooding possible
Sunday. Persistent surface boundary in vicinity next week
maintaining unsettled weather for upcoming days.
.NEAR TERM /THROUGH SUNDAY/...
As of 200 PM Saturday...
Radar this afternoon shows light returns falling across eastern
Ohio, but observations suggest dry air near the surface is still
winning out, and therefore very little accumulations have
occurred. These showers will increase in coverage overnight
ahead of a surface low pressing into the forecast area. Highest
rainfall amounts overnight are progged to occur in Perry County
and further west into ILN's CWA, where 0.75 to 1 inch of
rainfall is expected to fall. A frontal boundary will slowly
sink southward on Sunday and stall out north of the region for
the upcoming days, leading to an active weather pattern for the
start of the work week. On top of the boundary, other features
of note will be the increasing warm advection, moisture
advection, and hearty convection possible on Sunday, leading to
heavy bursts of rain and potential flash flooding.
A severe threat is also on the table for tomorrow, with SWODY2
depicting a Marginal Risk for strong thunderstorms. How much
sunshine we see throughout the day Sunday ahead of developing
convection will play a role in the convective threat. NAM and
GFS hint at surface CAPE on the order of 1500-2500 J/kg by 21Z,
coincident with PWATs of around 1.5 inches, pointing to an
unstable environment for the afternoon and evening.
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 240 PM Saturday...
Shortwave energy ejecting out of the mid Mississippi valley on Sunday
evening will lead to the development of a complex of storms
that will move across the lower Ohio Valley, with the complex
moving to the NNE towards our area in the late evening and into
the overnight hours. With a SW-to-NE frontal boundary draped
across the central Ohio Valley and outflow boundaries across the
region, plenty of focus for storm development will be present.
The beginning of the new work week will continue with the same unsettled
pattern. Thus, chances of showers and storms each day will
persist amid the quasi-zonal flow regime and multiple waves of
embedded disturbances rippling through the flow aloft.
On Monday, the frontal boundary will be slightly further south
than its position on Sunday, which should leave it somewhere in
the area of northern KY into southern OH and northwest PA.
Regardless of the boundary's exact position, some
destabilization is expected to occur south of the frontal zone
by Monday afternoon. Models are generally hinting at MLCAPE
values in the 1000-1500 J/kg range and with a belt of midlevel
westerlies around 35-40 kts moving across the region, some
severe threat could exist. As a result, the Day 3 Outlook from
SPC has our region in a Marginal risk for storms. In addition,
will need to monitor the flood risk as forecast soundings show
fairly tall/skinny CAPE profiles and warm cloud depths around 10
kft will be present in an environment of PWATs around 1.7-1.9
inches. With little change in the moist environment discussed
above and more favorable antecedent conditions from the rainfall
in previous days, the threat could become more elevated on
Tuesday as a shortwave trough and associated surface wave eject
out of the mid Mississippi Valley. Showers and storms will then
continue into Wednesday, though POPs will be slightly less as
there may be less organized forcing in the region.
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 240 PM Saturday...
The unsettled pattern continues into the long term period,
though POPs will be slightly less Wednesday compared to previous
days as there should be less organized forcing in the region.
Models then show a low pressure system moving across the Ohio
Valley/Great Lakes on Thursday, helping to push a cold front
through the region and a widespread risk of showers and storms.
Some drier air is expected to filter into the region by Friday
behind the front, which will bring our lowest daily POPs of the
entire week into the forecast. However, any break in the active
pattern appears to be short lived as the start of next weekend
could feature showers and storms once again.
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
As of 150 PM Saturday...
This will be the last day of widespread VFR for the foreseeable
future as subsidence at the surface shifts eastward, opening
the door to multiple disturbances over the next few days. Mid to
high level clouds are scooting into the Ohio River Valley this
afternoon, with radar showing light returns passing over WFO ILN
airspace. Dry air is still percolating near the surface at the
time of this issuance, forcing most of the hydrometeors to
evaporate before reaching the ground. While this may be the case
now, by this evening the northwest portions of the forecast
region will see showers and a thunderstorms press overhead
through the overnight hours. As a shortwave surges into Central
Appalachia tonight, we'll see a deterioration in ceilings below
10 kft, dropping further down into MVFR status at PKB, CKB, and
EKN Sunday morning. These restrictions will likely hold through
the remainder of the TAF period, while struggling to inflict
other terminals to drop down into MVFR.
Low level jet intensifies overnight across the region, leading
to another gusty afternoon at all terminals on Sunday. H85 winds
will increase to 40-45 kts during the overnight period,
decreasing slightly before sunrise. Forecast soundings depict
momentum transfer readouts extending above 3 kft, dragging down
winds that could result in gusts nearing 20 kts through the
course of the day.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: Medium.
ALTERNATE SCENARIOS: LLWS possible at CKB overnight in response
to strengthening low level jet.
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 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H 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 H H H 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 18Z SUNDAY...
IFR conditions possible in rounds of showers and thunderstorms
the middle of next week.
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