Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
629 PM EST Friday Mar 7 2014
tranquil weather through the day Saturday. Weak cold front Saturday
night. Mild early next week. System midweek followed by cold high
pressure to end the work week.
Near term /through Saturday/...
630 PM update...
Made only some minor tweaks to mint and sky grid per latest lamp guidance.
Otherwise no changes.
Previous discussion below...
17z visible satellite showing a generally clear sky over most of the
forecast area...with the last of the clouds from the system over
the southeast Continental U.S. Departing the east slopes of Pocahontas and
Randolph counties. Expect these to be gone in the next 2-3 hours.
Temperatures early this afternoon have rebounded nicely with current
readings generally upper 40s and lower 50s across The Lowlands.
Quiet weather in store for the forecast area in the near term...with
our area sandwiched between this morning/S system continuing to pull
off to the northeast and the next cold front slated to move through
Tonight begins mostly clear but will see an increase in high cirrus
towards the morning hours. Near-calm winds early on will begin to
set up from the south/southwest. Some weak warm advection at 850mb
is noted which may hold temperatures up just a bit west of the Ohio
River...but suspect most WV lowlands probably able to stay under and
cool nicely. Previous forecast mins generally lower and middle 30s lowlands
still on track with only a few minor tweaks. Did nudge ekn down a
Saturday flow aloft quickly backs from northwest to zonal. Winds
continue to veer from SW to west during the afternoon with surface high
pressure over the southeast Continental U.S. And cold front approaching from the
north. Clouds will continue to increase from northwest to southeast
during the day...with mostly cloudy skies under high and middle level
clouds across southeast Ohio by 18z. Most of the West Virginia zones should
remain generally partly cloudy a bit longer with the more dense
cloud cover not arriving until middle/late afternoon. Nudged maximum temperatures
upward by a couple of degrees based on latest prognosticated 850mb/925mb
temperatures and MOS guide. Have mainly middle/upper 50s for The
Lowlands...and a few 60-degree readings would certainly not be out
of the question from roughly the I-64 corridor south into the
coalfields. Hung on to lower 50s further north with slightly cooler
off-surface temperatures and cloud cover arriving quicker. Kept slight chance
and low chance probability of precipitation by and after 21z Sat with the approaching cold
front...with the bulk of the precipitation coming in the short-term
Short term /Saturday night through Monday/...
model differences continue with the timing of the cold front
Saturday night. The NAM is slower...while the European model (ecmwf)/GFS and Canadian
are faster. Will lean more toward the majority of models...but leave
a trailing slight chance since this period is getting into the short
term where the better resolution of the NAM can cause it to beat the
High pressure then builds in on Sunday and continues into the
beginning of the work week. GFS shows a boundary sliding into
northern West Virginia Monday afternoon...but with limited
moisture...no precipitation is expected.
Long term /Monday night through Friday/...
upper level pattern re-amplifies this period...with ridge rebuilding
over The Rockies...and deepening l/west trough over the eastern Continental U.S..
The main forecast issue this period is what happens with middle stream
energy as short wave troughs in the northern and middle streams move southeastward in
concert through the middle of the continent Tue-Wed. The GFS shows a
positive tilt middle stream trough that the northern stream basically falls
into...generating a flat wave at the surface. The European model (ecmwf) continues to
show a large system...as the middle stream short wave closes off...generating
more vigorous cyclogenesis at the surface. This may have to due with
its bringing in some southern stream energy from the 4 corners area
The GFS flat wave solution would entail a surface low track faster and
farther S and east...allowing the cold air to pour southward into the area
late Wednesday with anafront precipitation. The Gem is flatter
still...while the slower...deeper and farther north and west track of the
ecmwfhires surface low would pump warm air into the area Tuesday nt into
Wednesday...before tracking right over the area Wednesday evening. The colder
air would then pour southeastward into the area Wednesday nt...as the surface system
pulls away...but strong low level convergent upslope flow beneath
the broad upper level low...may prolong the precipitation a
bit...into Thursday morning. The system is a bit slower on most models
compared with their respective previous several runs.
Drier...colder air then closes out the work week in either
case...with high pressure crossing Friday. This high looks to be an
odd bridging of highs of Arctic and Pacific origin.
Period starts mild ahead of the middle week system and on into Wednesday
when the system enters the area. With the differing solutions...used a
blend of the European model (ecmwf) and GFS for 6 hourly temperatures late Tuesday nt
into Wednesday nt. This puts highs Wednesday below most of the guidance but
close to wpc. Stayed on the low side of guidance and close to wpc
through Friday. Rain likely Wednesday followed by the chance for snow Wednesday nt
and a diminishing chance for show showers Thursday.
Aviation /00z Saturday through Wednesday/...
00z Saturday through 00z Sunday...
VFR conditions will prevail through much of the valid
period...with light and variable winds today becoming calm
overnight...and finally light out of the south/southwest by the
morning hours on Saturday in advance of a cold front to pass the
area later Saturday night. Mostly clear skies early during the
overnight hours...with a gradual increase in high and middle level
clouds into Saturday. Cold front will be entering southeast Ohio around the
end of the taf period with perhaps some MVFR ceilings along and just
behind the boundary. A spotty rain showers/shsn may also accompany the front.
Forecast confidence and alternate scenarios through 00z Sunday...
Forecast confidence: medium.
Alternate scenarios: there could be some valley fog overnight given
the wet grounds and small dewpoint depressions.
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 00 01 02 03 04 05 06 07 08 09 10 11
EST 1hrly 19 20 21 22 23 00 01 02 03 04 05 06
crw consistency h h h h h h h h l l l l
heights consistency h h h h h l l l l l l l
bkw consistency h h h h h l l l l l l l
ekn consistency h l l l l l l l l l l l
pkb consistency h h h h h h l l l l l l
ckb consistency h h l l l l l l l l l l
After 00z Sunday...
IFR possible in a strong low pressure system Wednesday.