Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
432 am EDT Friday may 22 2015
a weak cold front pushes south today...with a few showers
possible. High pressure takes control later tonight...and brings about
a dry Memorial Day weekend...with a warming trend.
Near term /through tonight/...
no major changes were needed to the previous forecast. Still have
some lingering low clouds across the higher terrain counties
tonight. These should generally dissipate by late this morning.
Across the northern 2/3 of the County Warning Area...clearing...with some patchy
valley fog developing...with drier air across the north...trying
to work its way into the County Warning Area.
Focus shifts to a weak cold front that will sink south across the
area today. Not much moisture or forcing associated with it...so
kept only slight chance to chance probability of precipitation in the forecast. Front will
wash out across the south late tonight...with high pressure
building into the region later tonight and Saturday. Dew points
late tonight across the north/northeast should dip into the
30s...as drier air moves in. Across the south...higher dew
points...and greater cloud cover expected. Could see some patchy
frost across the northeast tonight...and a frost advisory may be
needed. Will have day shift reevaluate...and will put a mention in
the severe weather potential statement.
Short term /Saturday through Monday/...
could not be much better a Memorial Day weekend on tap. A large
high pressure system...having built in over the area behind a near
term cold front...slowly drifts east of the area during this period.
After the chilly start Saturday morning...this allows a S to SW
flow of warmer air to bring about moderating temperatures
throughout the weekend. Highs and lows recover to at least normal
Saturday and Saturday night...and then above normal thereafter.
Removed probability of precipitation late Sunday and Sunday night. Models hold off on
appreciable forcing from the west until Tuesday...but moisture and
instability could increase enough for a pop up shower or
thundershower Memorial Day afternoon.
Raised highs based on latest guidance and forecast 850 mb
temperatures...except for Memorial Day itself...which looked
reasonable. Lowered lows Saturday night and a bit Sunday
Long term /Monday night through Thursday/...
again...there remains a bit of uncertainty with the extended
portion of the forecast...and continued to not make many changes.
Low pressure will set up across the northern plains through the
period...with the warm front moving north on Sunday and remaining
to the north afterwards. While the cold front will remain to the
west...the front should be close enough to allow for a chance of
showers and isolated thunderstorms through much of the period.
Once the warm front passes to the north...southerly flow will
allow for a return to above normal temperatures.
Aviation /08z Friday through Tuesday/...
MVFR and local IFR ceilings continue to remain across the
mountains...affecting sites such as kbkw and kekn. These should
generally dissipate in the 12-15z time frame. Elsewhere...mainly
VFR conditions...although patchy River Valley fog is starting to
form...creating local IFR conditions. Any fog that develops will
dissipate after 12z for a return of VFR conditions with light
A weak cold front will sag south across the area today. Not much
moisture associated with the front...but generally...local MVFR
conditions in -shra can be expected...generally along and north of
a line from kcrw to kckb in the 20-02z time period. Most locations
should remain VFR however.
At this time...widespread fog development doesnt appear to be an
issue for Friday night...although some patchy MVFR fog developing
in favored river valleys closer to 06z cannot be ruled out.
Forecast confidence and alternate scenarios through 00z Friday...
Forecast confidence: medium.
Alternate scenarios: timing...or even existence of fog may vary.
Timing of ceiling changes may vary.
After 06z Saturday...
widespread IFR not expected.