Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Charleston WV
340 PM EST Tuesday Mar 3 2015

cold front tonight. Front stalls to the south with low pressure
moving along the front Wednesday night. Snow showers linger on
Thursday. High pressure Friday.


Near term /through Wednesday/...
models continue to advertise a heavy rain event over the next 24
hours...transitioning to a heavy snow event by Wednesday afternoon
mainly west of the Ohio River. A slow moving cold front will drop
southeast across the area later tonight and Wednesday and will be
the focus for widespread rain that will be heavy at times. A Flood
Watch remains in effect for the entire area from this evening
Onward...although the heaviest rains tonight will be over the
northwest half of the area...spreading southeast over the remainder
of the area by Wednesday. Snowmelt will also be a factor especially
in the mountains to enhance potential flooding. For the transition
to snow...we will blend the faster GFS/CMC solution and the slower
NAM/ECMWF. In any event...all models show a heavy rain to be
followed by a heavy snow event. So the transition to snow will be
occurring over mainly southeast Ohio Wednesday afternoon. We have
upgraded the Winter Storm Watch to a warning for most of the
counties along and west of the Ohio River Wednesday afternoon. The
remainder opf the area...except for the far south...remains in a
Winter Storm Watch. Temperatures will be mild tonight...not falling
much until the cold front starts progressing across the area. The
front itself will most likely reach the mountains by Wednesday
morning...with falling temperatures through the 30s during
Wednesday. So...the main rain event will be from one wave moving
along the slowly progressive front tonight and Wednesday
morning...then followed by a second wave in the colder that will be
responsible for the change to snow.


Short term /Wednesday night through Friday/...
an extremely strong upper level jet will provide support for a
prolonged period of rain and snow associated with a slow moving cold
front. By Wednesday night the rain will be transitioning to sleet
and eventually to snow. A Winter Storm Watch remains in effect for
much of the area and winter storm warnings have been hoisted for the
western portion of the forecast area where confidence is higher in
receiving impactful winter weather. Kept the watch in effect for the
eastern portion of the area due to the uncertainty associated with
the timing of the changeover and the duration of sleet that should
occur during the transition period.

Models generally agree on the intensity and duration with the GFS
being the one outlier pushing the cold air through faster and
subsequently keeping the area a bit drier. Opted to still consider
this in the forecast...but blended towards the slower wetter
solutions which is more in line with the wpc thinking.

Precipitation should start to subside by Thursday afternoon. High
pressure builds in on Friday.


Long term /Friday night through Tuesday/...
high pressure in place to start the long term period...gradually
being squashed to the south as an upper level shortwave trough drops
through the western Great Lakes Sunday. Models struggling some with
this feature...both in speed and just how far south precipitation
with this will make it. Have another 500mb shortwave trough
following the first around Monday. 00z European model (ecmwf) tries to keep these to
features separate...while GFS does not have much of a break between
them. Ended up with a near 50/50 blend of GFS/European model (ecmwf) through the long
term for probability of precipitation. Generally stuck close to wpc for temps/winds.


Aviation /21z Tuesday through Sunday/...
have a break in the rain this afternoon. Look for general MVFR
conditions to prevail across southeast Ohio and possibly just VFR conditions
in the warm sector across ekn amid downslope winds. IFR conditions
look to develop on east slopes including kbkw this afternoon. There
will be only a slight chance of an embedded thunderstorm southeast
portions of area this afternoon and night.

The front sags southeast tonight...clearing southeast Ohio by 06z...c WV by
09z...and into the mountains by 12z. Heavy rain will fall along
the baroclinic zone...sending aviation conditions into IFR or worse.

Southerly winds will generally be light in The Lowlands...but
gusts will be increasing to around 25 knots on Mountain Ridge
tops this morning...including kbkw.

Forecast confidence and alternate scenarios through 18z Wednesday...

Forecast confidence: low to medium.

Alternate scenarios: lowering of flight categories to MVFR/IFR will
vary with onset of the rain tonight.

Experimental table of flight category objectively shows consistency
of weather forecast office 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 20 21 22 23 00 01 02 03 04 05
06 07 EST 1hrly 15 16 17 18 19 20 21 22 23
00 01 02 crw consistency h h h h h h M
M h h h h heights consistency h h h M M M
M M h h h h bkw consistency h h h h M
M M M M M M h ekn consistency h h h h
h h h l l M M M pkb consistency h h M
M M M M M h h h h ckb consistency M M
M M M h M M h h h h

After 18z Wednesday...
IFR possible in rain Wednesday...and rain/sleet or snow
late Wednesday afternoon and Wednesday night. IFR in snow showers


Rlx watches/warnings/advisories...
WV...Flood Watch from 7 PM EST this evening through Thursday
morning for wvz005>011-013>020-024>040-046-047.
Winter Storm Watch from Wednesday afternoon through Thursday
afternoon for wvz005>008-013>020-026-029.
Winter Storm Watch from Wednesday evening through Thursday
evening for wvz027-028-030>032-035>040-046-047.
Winter Storm Warning from 4 PM Wednesday to 1 PM EST Thursday
for wvz009>011.
Ohio...Flood Watch from 7 PM EST this evening through Thursday
morning for ohz066-067-075-076-083>087.
Winter Storm Warning from 4 PM Wednesday to 1 PM EST Thursday
for ohz085>087.
Winter Storm Warning from 1 PM Wednesday to 1 PM EST Thursday
for ohz066-067-075-076-083-084.
Kentucky...Flood Watch from 7 PM EST this evening through Thursday
morning for kyz101>103-105.
Winter Storm Watch from Wednesday afternoon through Thursday
afternoon for kyz105.
Winter Storm Warning from 4 PM Wednesday to 1 PM EST Thursday
for kyz101>103.
Virginia...Flood Watch from 7 PM EST this evening through Thursday
morning for vaz003-004.


near term...jmv
short term...jw

National Weather Service Glossary of Abbreviations