Flash Flooding and Hail in West Virginia, April 7 to 10, 2020

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
640 AM EDT Tue Apr 7 2020

.SYNOPSIS...
Warm front north today followed by cold front overnight. A much
stronger cold front Thursday. Another system arrives Saturday
night or Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 635 AM Tuesday...

Bumped up POPs a bit first thing this morning across the central
forecast area per radar trends. HRRR has been fairly consistent
in showing this development over past several model runs. Added
slight chance thunder in as well. These should fizzle as they
move east mid morning.

As of 155 AM Tuesday...

A warm front was noted across northern IN/OH with scattered
convection. This feature in conjunction with moist west
southwest low level flow and a passing mid level disturbance is
aiding will continue to aid in forcing for ascent. This
activity should increase in coverage as it tracks southeast into
the upper OH Valley this morning. Elevated convection will
continue with steep mid level lapse rates allowing for perhaps
a small hail threat. Mesoscale hi res models keep the majority
of this just north of the forecast area, perhaps skirting our
common border with WFO PBZ. An additional area for some early
morning elevated WAA showers will be across the Coal Fields
into southeastern WV, though confidence is low.

As we head into the early afternoon ongoing convection will try
to sneak into the northern portions of our forecast area. This
seems plausible given partial thickness contours. Should this
occur, storms would likely become surface based given increasing
ML CAPE on continued southwesterly warm moist low level moist
advection. Model soundings for PKB/CKB/EKN are worrisome with
large hail/damaging wind/isolated tornado threat all on the
table. This remains a low confidence forecast, however, given
the uncertainty in just how far south activity will migrate.
This is especially true given the proximity of capping inversion
farther south in our area.

We should see a lull heading into this evening as EML plume
overspreads the remainder of the region in advance of an
approaching mid level disturbance and associated surface front.
This will prime the atmosphere for a damaging wind potential
along with a large hail threat overnight as initial convection
upstream across the Lower Great Lakes organizes and races
southeast into the area. Timing this feature on the mesoscale
models remains problematic with varying solutions. I've opted
to lean toward the faster solutions given the overall setup. As
such, at least a broken line of strong to severe convection is
forecast to enter southeast OH around midnight or just prior,
,into the central portions of the CWA a few hours later, and
exiting to the south during the predawn hours.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
As of 155 AM Tuesday...

A weak cold front will push southward through the region on
Wednesday providing some showers, and possibly thunderstorms in
southern West Virginia and southwestern Virginia.

Another much stronger cold front moves through late Wednesday
night into early Thursday. Despite the time of day, soundings
show enough instability for thunderstorms across much of the
area. Much colder air moves into the area Thursday and Thursday
night behind the front. Models still have some disagreement in
the timing and number of upper air disturbances moving through
for later Thursday into Friday. These could provide some light snow
to the higher elevations of the northern West Virginia mountains.

A high pressure system then builds across the area for Friday
night. With dry air in place and winds becoming calm, a
frost/freeze is possible.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
As of 155 AM Tuesday...

High pressure will continue on Saturday.

Models then show energy ejecting out of the southwestern US to
produce a system over our area beginning Saturday night or
Sunday and continuing into Sunday night. While there are some
timing differences, models are in much better agreement than
last night. Colder air moves in behind this system Monday and
Monday night.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
As of 635 AM Tuesday...

Isolated SHRA/TSRA this morning in the vicinity of CRW/BKW that
should fade by mid morning. A warm front north of PKB/CKB/EKN
will serve as the primary focus, however, for SHRA/TSRA through
the morning hours.

Convection near the warm front will try to slip south midday
and into the afternoon hours to affect the northern terminals.
Confidence is not particularly high, but enough to include VCTS
in otherwise VFR conditions. Any convection that forms may be
strong to severe with damaging winds and large hail possible.

A lull is expected this evening before SHRA/TSRA race southeast
into the area overnight along an approaching frontal boundary.
A damaging wind threat and large hail threat exists for all
terminals as this progresses through the area in the 06-12Z time
frame in addition to IFR conditions. For now, I have some PROB30
groups for IFR TSRA.

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

FORECAST CONFIDENCE: High except medium for PKB/CKB/EKN this
afternoon.

ALTERNATE SCENARIOS: Showers and storms may stay north of
northern terminals today. Timing of convection tonight may vary
an hour or two from forecast.

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  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 12Z WEDNESDAY...
IFR conditions possible along the mountains Wednesday morning.

&&

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

&&

SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...RPY
AVIATION...30

Hazardous Weather Outlook
National Weather Service Charleston WV
342 AM EDT Tue Apr 7 2020

KYZ101>103-105-OHZ066-067-075-076-083>087-WVZ005>011-013>020-024>032-
034-039-040-080745-
Greenup-Carter-Boyd-Lawrence KY-Perry-Morgan-Athens-Washington-
Jackson OH-Vinton-Meigs-Gallia-Lawrence OH-Wayne-Cabell-Mason-
Jackson WV-Wood-Pleasants-Tyler-Lincoln-Putnam-Kanawha-Roane-Wirt-
Calhoun-Ritchie-Doddridge-Mingo-Logan-Boone-Clay-Braxton-Gilmer-
Lewis-Harrison-Taylor-Wyoming-Upshur-Barbour-
342 AM EDT Tue Apr 7 2020

This Hazardous Weather Outlook is for northeast Kentucky, southeast
Ohio, and portions of central West Virginia, northern West
Virginia, southern West Virginia and western West Virginia.

.DAY ONE...Today and Tonight.

A slight risk of severe thunderstorms exists for the entire area
today and tonight. Isolated to scattered strong to severe
thunderstorms may occur in the afternoon across northern West
Virginia. Large hail, damaging winds, and an isolated tornado are all
possible.

Scattered strong to severe thunderstorms or a line of storms may
impact much of the area late tonight. Damaging winds and large hail
are possible.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

A much colder airmass will settle in for the end of the week. A
frost advisory or freeze warning may eventually be needed for Friday
night and early Saturday morning.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions by calling the toll-free spotter hotline, or by other
methods detailed at www.weather.gov/rlx/reports.

VAZ003-004-WVZ033-080745-
Dickenson-Buchanan-McDowell-
342 AM EDT Tue Apr 7 2020

This Hazardous Weather Outlook is for southwest Virginia and
southern West Virginia.

.DAY ONE...Today and Tonight.

There is a marginal risk for severe thunderstorms late tonight with
large hail and damaging winds possible.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

A much colder airmass will settle in for the end of the week. A
frost advisory or freeze warning may eventually be needed for Friday
night and early Saturday morning.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions by calling the toll-free spotter hotline, or by other
methods detailed at www.weather.gov/rlx/reports.

WVZ515>526-080745-
Northwest Raleigh-Southeast Raleigh-Northwest Fayette-
Southeast Fayette-Northwest Nicholas-Southeast Nicholas-
Northwest Webster-Southeast Webster-Northwest Pocahontas-
Southeast Pocahontas-Northwest Randolph-Southeast Randolph-
342 AM EDT Tue Apr 7 2020

This Hazardous Weather Outlook is for portions of northeast West
Virginia and southeast West Virginia.

.DAY ONE...Today and Tonight.

A slight risk of severe thunderstorms exists for the entire area
today and tonight. Isolated to scattered strong to severe
thunderstorms may occur this afternoon across northern West
Virginia. Large hail, damaging winds, and an isolated tornado are all
possible.

Scattered strong to severe thunderstorms or a line of storms may
impact much of the area late tonight. Damaging winds and large hail
are possible.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions by calling the toll-free spotter hotline, or by other
methods detailed at www.weather.gov/rlx/reports.