Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
305 am EDT Tuesday Oct 13 2015
cold front pushes to our east early today. A reinforcing cold
front then pushes southeast Wednesday...with a stronger cold
front on Friday. High pressure brings a chilly weekend.
Near term /through tonight/...
latest surface map shows a cold front was pushing across the
region. An area of showers was located to the east of the front.
The front is expected to push to the east later this morning...
taking the showers with it. Satellite imagery and model data
suggest some sunshine is possible in the wake of the precipitation this
morning. However...NAM/GFS suggest a middle-level shortwave will
swing southeast across the region later today into tonight.
Moisture should be limited...so only see some additional clouds
with this feature.
With clouds and cold air advection...feel temperature guidance for highs
today is too warm...but have bumped afternoon readings up a
little to reflect this trend. Guidance for tonight is quite close
to earlier thinking...so only minor tweaks made.
Short term /Wednesday through Friday/...
deep layer west to northwest flow Wednesday gives way to surface high pressure by Thursday
morning...which in turn gives way to a new cold front Thursday nt.
The NAM was rather bullish on moisture atop the mixing layer Wednesday
into Thursday...the drier GFS looked more reasonable. The moisture
will likely be realized as morning cumulus Wednesday before mixing out Wednesday
While there were some differences in timing and southward extent of
moisture associated with the cold front...all models more or less
whip the front through the area overnight Thursday nt...with clearing
rushing into the middle Ohio Valley first thing Friday morning in its
wake. Have return to dry weather throughout the area by Friday
afternoon as surface ridging builds in from the west.
Met looked good for highs Wednesday...close to previous except a bit
lower over the higher terrain. Highs Thursday looked good...close to
the met. Blended in the mex for highs Friday...again lower over the
higher terrain compared with previous. Blended in met and mav for
lows Wednesday and Thursday nts...a bit lower than previous for the most
Long term /Friday night through Monday/...
a cold front will slide through Friday as a surface low moves across
southeastern Canada. Have chance probability of precipitation with this across the north.
Upper trough will linger through much of the weekend...with some
clouds but do not have any precipitation mentioned. Surface high pressure
then arrives for the remainder of the long term forecast. Should be
fairly cool behind the cold front...with highs in the 50s across The
Lowlands and 40s in the mountains this weekend. Lows will be cold
enough for potential of frost/freeze Saturday night across much of
County Warning Area...and possibly again Sunday night at higher elevations. Will
continue current severe weather potential statement mention for Saturday night. Will have dry
conditions in place Saturday and Sunday...so somewhat low relative humidity values
expected...but winds should be light with high pressure in the
Aviation /07z Tuesday through Saturday/...
an area of showers...associated with a cold front...was pushing
east across the area at 06z. MVFR conditions were occurring in the
heavier showers...with VFR conditions elsewhere.
Behind the front...MVFR conditions are possible through 14z. IFR
conditions are also possible in the mountains between 09z and 13z.
Conditions should then improve with most locations seeing VFR
conditions by 16z.
Southwest winds of 5-10 kts with some higher gusts this morning...
will become westerly by 18z...with gusts of 20 to 30 kts are
possible are possible over the mountains. The winds should then
decrease after 00z.
Forecast confidence and alternate scenarios through 06z Wednesday...
Alternate scenarios: development and extent of MVFR ceilings/visibilities may
vary from forecast through 14z.
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.
Date Tuesday 10/13/15
UTC 1hrly 06 07 08 09 10 surface high pressure dominates the forecast period with dry
atmosphere in place. Northwest flow will prevail at the middle
levels through the period. A weak front with light forcing and
limited moisture will pass late Tuesday night and early Wednesday. Models
starting to hint at possibility of isolated showers over NE mountains
with this feature. However...will hold off introducing probability of precipitation for
now. For temperatures...took a blended approach with only minor
adjustments made to the inherited forecast. But cooler air will be
filtering in on continued northwesterly flow aloft...leading to
cooler than normal temperatures for Thursday.
11 12 13 14 15 16 17 EDT 1hrly 02 03 04 05 06 07 08 09 10 11 12
13 crw consistency M M M M M M M M h h h h heights consistency M M M M
M h h h h h h h bkw consistency l M M M M M l l M h h h ekn
consistency l l l l l l l M M M h h pkb consistency M M M M M h h
h h h h h ckb consistency M M M M M M M l h h h h
After 06z Wednesday...
no widespread IFR expected at this time.