Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 270135
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
935 PM EDT Sun Mar 26 2017

.SYNOPSIS...
Active, mild pattern continues in a parade of southern stream
systems. One crosses this evening, followed by another Monday
night and Tuesday, and then again Thursday through Friday.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 920 PM Sunday...

Took out thunder for entire area before midnight. Rain showers
gradually decreasing from southwest to northeast after midnight,
confined to far northeast WV by morning.

As of 2 PM Sunday...

The remainder of the afternoon will tell what comes of a
negatively tilted trough axis pivoting through the middle Ohio
Valley, and the left front exit region of a strong jet on the
back side of the trough coming in close proximity of the
diffluent area ahead of the trough axis.

So far, only small breaks in the cloud cover have limited
surface heating. Heating was more evident farther south, beneath
and behind the upper level trough axis, where the first
thunderstorms were firing up in eastern Kentucky early this
afternoon. The WRFs appear to have this pegged as the beginning
of the main shower/thunderstorm activity crossing the area this
afternoon into this evening, as the categorical PoPs in the
forecast depict.

The low level reflection of the upper level trough is a warm
occlusion that will push through the area tonight. Loss of
daytime heating should end the thunderstorm threat tonight,
while the last of the showers should end once the occlusion
pushes through. Compromised between the faster GFS, HRRR and
RUC, and slower NAM and WRFs in winding down the precipitation
overnight tonight. Models depict morning stratus where the
surface occlusion stalls over the middle Ohio Valley on Monday.

The next short wave trough brings an increasing chance for
showers and thunderstorms from the southwest late Monday.

Used a blend of near term guidance for temperatures and dew
points, which did not bring up any major changes from the
previous forecast.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 4 PM Sunday...

Upper level southern stream short wave trough crosses Monday
night and Tuesday, bringing the next round of showers and
thunderstorms. However, the timing of the system is such that
the strongest thunderstorms will be to the west of the forecast
area Monday afternoon, and then to the east on Tuesday
afternoon.

The system pulls out Tuesday afternoon and evening, but is
likely to leave low level moisture behind in the form of stratus
overnight Tuesday night into Wednesday morning. High pressure
sails across to the north of the area Wednesday, followed by a
southeast flow developing in its wake by Thursday morning,
beneath an upper level ridge.

Temperatures close to central guidance and remaining above
normal, even in the wake of the system midweek.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 4 PM Sunday...

The next southern stream upper level low approaches Thursday
through Friday, before passing north of the area Friday night.
This brings a surface warm front, along with an initial round
of rain or rain showers, Thursday afternoon and evening.

The surface cold front crosses Friday evening, as the surface
low passes north of the area Friday night. Models have come in
good agreement on this system. Showers and thunderstorms are
most likely Friday into Friday night, but with the typical
downslope shadow effect west of the mountains Friday in strong
south to southeast flow in the warm sector ahead of the cold
front.

Northwest flow behind the system may bring upslope rain showers
in and near the WV mountains on Saturday, with the latter part
of next weekend more likely to bring dry weather. However,
models are not too divergent on timing of yet another southern
upper level low approaching late next Sunday.

Temperatures close to central guidance and lower than the MEX.

&&

.AVIATION /02Z MONDAY THROUGH FRIDAY/...
As of 920 PM Sunday...

An upper level disturbance will continue to bring showers into
the night time hours, mostly ending from southwest to northeast
by around 13Z Monday. Thunder potential will mostly dissipate
by 03Z with loss of heating. Look for brief MVFR/IFR VSBY in a
few of the heavier rain showers.

15 to 20 kts of southerly flow just above the surface should
generally keep IFR fog from becoming an issue. However,
prevailing VFR ceilings become MVFR ceilings after 06Z, but
with locally IFR ceilings possible mainly higher mountains. No
IFR is forecast for major TAF sites overnight. Expect clouds
lifting to VFR ceilings 3500-4500 feet by 15Z Monday.

The rest of Monday will bring dry VFR weather, with at most a
4-6kft stratocu deck.

Surface flow will become light south tonight, and then southerly
5 to 8 kts Monday afternoon.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z TUESDAY...

FORECAST CONFIDENCE: Medium

ALTERNATE SCENARIOS: There may be a bit more IFR ceilings
overnight and early Monday morning, and timing of improvement
to VFR on Monday may vary.

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                                                            MON 03/27/17
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    M    L
HTS CONSISTENCY  H    H    H    H    H    H    H    H    M    M    M    L
BKW CONSISTENCY  H    H    H    H    H    H    H    M    M    M    M    L
EKN CONSISTENCY  H    H    H    H    H    M    M    M    M    M    M    M
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    L    L    M
CKB CONSISTENCY  H    H    H    H    H    H    H    H    M    M    M    L

AFTER 00Z TUESDAY...
Brief IFR possible in thunderstorms Monday night and Tuesday.

&&

.EQUIPMENT...
Radar site KRLX appears to have a faulty component that is
leading to higher reflectivities than what should be observed at
times. So far today and this evening, however, the radar has
performed normally. Further evaluation and monitoring is
expected prior to action being taken.

&&

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

&&

$$
SYNOPSIS...TRM
NEAR TERM...JMV
SHORT TERM...TRM
LONG TERM...TRM
AVIATION...JMV

EQUIPMENT...99


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