Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
124 PM EDT Wednesday Aug 27 2014
weak cold front crosses this afternoon into tonight. Weak high
pressure dominates Thursday and Friday. Hotter and more humid
Saturday. Deeper moisture Sunday associated with disturbance
Near term /through Thursday/...
weak cold front at 16z entering southeast Ohio zones...with
convection firing along the front in the afternoon heating.
Frontal boundary will slowly sink south across the area this
evening and tonight...ending up across the southern zones by 12z
Thursday. Still expecting bulk of convection this afternoon and
evening across the northern half of the County Warning Area...with a general wane
in the bulk of activity with loss of heating...although did
continue to maintain a slight chance overnight as the frontal
boundary continues to sag south.
Models are continuing to indicate an environment conducive to fog
development across the north...I.E. Southeast Ohio and adjacent WV
counties...with stratus across much of WV/southwest Virginia...zones.
Continued to maintain a forecast reflective of this overnight.
Areas that get rain today...particularly across the north...will
likely be socked in in fog tonight.
Made little changes to temperatures during the period.
Short term /Thursday night through Saturday/...
still thought the 00z NAM solution was a bit quick/fast drying out
the low level moisture...left in the dew point gradient associated
with the weakening front. So will hold onto a slight chance probability of precipitation in
some of our southern WV and southwest Virginia counties Thursday
morning...mainly bkw on SW. By afternoon...will have that slight
chance probability of precipitation lingering for a shower or storm just in our 2 Virginia
counties Thursday afternoon. Certainly the further north/northeast
on Thursday...the drier the air.
The 500 mb ridge axis moves over US on Friday...so we lose the northwest
flow aloft. At or below 850 mbs though the weak flow is somewhat southeast and
upslope into our eastern slopes. Will continue the chance probability of precipitation
Friday afternoon from our Greenbrier valley on SW in the southern WV
mountains to SW Virginia.
The only chance made to Saturday was to increase maximum
temperature. The last of the dry air that was shoved on the way
down into the deep south will return NE...through our vicinity on
Saturday. 850 mbs temperatures near 20c.
Long term /Saturday night through Tuesday/...
used wpc thinking with some tweaks. West to southwest flow with
several middle-level disturbances will result in on and off chances
of showers and storms. A cold front will approach from the
northwest late in the period...with this feature possibly pushing
across the area by late Wednesday.
Best chance of getting wet still appears to be on Sunday...when a
decent shortwave passes by.
Wpc temperatures looked good and were generally used.
Aviation /17z Wednesday through Sunday/...
mainly VFR conditions through about 06z...although isolated
convection is expected mainly through 03z...mainly across
southeast Ohio...northeast Kentucky...and northern/central WV. Expect
brief low VFR/MVFR conditions in vicinity of storms.
Otherwise...after 06z...expecting MVFR/IFR fog formation across
parts of southeast Ohio...northeast Kentucky...and northern
WV...particularly in areas that receive rain...such as at
khts...kpkb...and kckb. Expecting widespread MVFR stratus to
develop across central and southern/eastern WV...mainly after
06z...affecting sites kekn...kbkw...and kcrw.
Forecast confidence and alternate scenarios through 18z
Forecast confidence: medium.
Alternate scenarios: timing and density of fog/low stratus may vary
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 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 h h h h h h h h h h h h
heights consistency h h h h h h h h h h h h
bkw consistency h h h h h h h h h h h h
ekn consistency h h h h h h h h h M h h
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 M M
After 18z Thursday...
local IFR in valley fog early Friday morning. IFR possible in