Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 231901
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
301 PM EDT Sun Apr 23 2017

.SYNOPSIS...
Upper level low passes to our south tonight and then swings
east to the Carolina coastal states Monday, keeping rain mainly
in the south and east through Monday. Warmer midweek before a
cold front crosses Thursday night.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 200 PM Sunday...

While there are typical model differences in the exact handling
of the broad upper low currently over the western Tennessee
valley this period, all are indicating SIMILAR main effects for
our area. The associated rain shield just over our southern
most zones early this afternoon will struggle to shift northward
this afternoon and evening. As the upper low slides south
southeast into the southeastern states tonight, the rain shield
will tend to shift slowly eastward and spread up the WV
mountains. This process will continue Monday as the upper low
then reaches the Southeast coast. By Monday afternoon, most of
the rain will have shifted into the mountains. Thus, will keep
the northwest half basically dry and the southeast quite wet,
with a tight POP gradient in between. In addition, the good
influx of moisture and steady but persistent rain over the
southern mountains will validate continuing the Flood Watch as
is, with flood warnings already in effect for SW VA. The watch
may very well have to be extended and expanded up the mountains
later tonight and Monday, but there is enough uncertainty in the
exact track of the upper low and the axis of heavy rain for
further evaluation. Otherwise, look for coolest temps tonight
and warmest temps Monday over northwest portions of the area
given less thick clouds and lack of rain.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 245 PM Sunday...

Influences from the cut off upper low over the Southeast will
continue through Tuesday as an inverted trough remains over the
area. Precipitation chances will largely be confined to the
eastern half of the CWA, while the low and mid level moisture
starts to dissolve CWA wide after Tuesday. Improvements expected
all around with temperatures on the increase, and the far
southern zones drying out after a few days of persistent rain.
Expecting a significant increase in 500mb heights heading into
Wednesday, and an 850mb temperature jump of 5-8C. In the
meantime, the upper trough merger over the central states will
be occurring.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 245 PM Sunday...

Getting quick cyclogenesis occurring with the upper trough
merger over the Midwest, and a strong frontal system deepening
into the western Great Lakes. The models continue to take it
towards northern Ontario, so the cold front is still expected to
shear out considerably as it passes through the Ohio Valley.
Still needing POPs into Thursday, with thunder, but overall it
should be a weakening cold front as it affects our area.

Strong upper level ridge builds over the southeastern states
while a southern plains upper low deepens, developing another
surface low. Warm frontal influences keep low end chances for
precipitation into the weekend, but the temperature trend
continues to go upwards, with summer like readings prevailing.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
18Z Sunday thru 18Z Monday...
As of 1145 AM Sunday...

Quite a gradient of Flight Categories this period.

Upper level low currently centered over the Tennessee Valley
will slowly drop south and east this afternoon and tonight.
However, it is broad enough to pull deeper moisture and
widespread rain northward into parts our area this afternoon
and tonight. Northern edge of rain by 00Z will be just south of
HTS-CRW-W22 line with the south quite wet and the north
remaining dry. Tonight will see this rain shield shift toward
the east and expand up eastern WV, with the back edge of the
rain mainly along and east of a CRW-CKB line by 14Z.

Look for VFR ceilings to mostly persist outside of the precip
shield this period, mainly at PKB and CKB. Mostly MVFR/IFR IN
the precip shield, with MVFR prevailing at HTS,CRW, and possibly
EKN. IFR/LIFR in the southern and central mountains including
BKW.

Wind will be easterly at 5 to 10 KTS, except 10 to 20 KTS
higher mountain elevations.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...


FORECAST CONFIDENCE: Low to Medium.

ALTERNATE SCENARIOS: A minor shift in the upper low movement
may greatly affect timing and development of rain across the
area.

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

AFTER 18Z MONDAY...
IFR possible into Monday with another wave of low pressure.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Flash Flood Watch until midnight EDT tonight for WVZ033-034.
OH...None.
KY...None.
VA...Flash Flood Watch until midnight EDT tonight for VAZ003-004.

&&

$$
SYNOPSIS...JMV/26
NEAR TERM...JMV
SHORT TERM...26
LONG TERM...26
AVIATION...JMV


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