Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
1008 am EDT Monday Mar 30 2015
high pressure today and tonight. Cold front Tuesday/Tuesday night.
Near term /through tonight/...
1000 am update...no significant changes made. Did update morning probability of precipitation
based on radar trends.
swift moving cold front exits the mountains after 12z this
morning in a clean sweeping fashion without lingering low level
moisture. Therefore...during the afternoon hours...should see only
some flat diurnal cumulus cloud cover. This will mix some drier
air back to the surface this afternoon along with the potential
for some breezy conditions at times...but the dry air will not
exhibit the low dewpoints seen before the current front arrived.
Avoided the met guidance for this issuance as the error points were
too high for the previous maximum temperatures. Instead...opted for the bias
corrected mav...but modified heights and crw which looked a little too
Short term /Tuesday through Thursday night/...
last clipper type low pressure system and cold front in northwest
flow aloft...will rapidly drop across the area later Tuesday and
Tuesday night. Not too much fanfare in the weather as moisture will
be limited. The track of the low itself by all the models will be
just north of our area. Most of the dynamics and thus the rain
associated with this quick moving system will also be just north of
our area. Will generally confine chance probability of precipitation for rain showers to
northern areas. In any case...any quantitative precipitation forecast will be very light. Changeable
temperatures will be the biggest feature...quite warm Tuesday ahead
of the front and cooler Wednesday. Brief high pressure Wednesday.
Models continue to advertise a major change in the pattern.
This change leads to a frontal system stalling across the area
later Thursday and Friday under nearly zonal flow aloft. With the
mean surface high setting up off the southeast U.S. Coast...the Gulf
of Mexico moisture and instability will be tapped as southerly flow
feeds into the frontal system. While the details are yet to be
established with waves of low pressure rippling along the
front...the result in general will be an extended period of wet
weather with widespread showers and possibly thunderstorms. The
front will finally get a push by Saturday as a significant upper
trough passes through. Quite warm Thursday ahead of the
front...cooler Friday with all the clouds and rain.
Long term /Friday through Sunday/...
generally followed HPC. While a significant warm up is expected middle
to late week...it may be hampered by showers on late Thursday and
into early Friday as a pesky disturbance comes out of the S stream
before heights can build. The main system will be Friday evening. A
the weekend is shaping up to be seasonal and mainly dry.
Aviation /14z Monday through Friday/...
low level moisture should not last very long once mixing
begins...so have the MVFR ceilings dissolving in the tafs fairly
quickly this morning. Bring some gusts in the 15-20kt range this
afternoon as well with the daytime heating and diurnal flat
cumulus clouds above 4kft. A batch of high level moisture moves
across the northern terminals tonight.
Forecast confidence and alternate scenarios through 12z Tuesday...
Forecast confidence: medium to high.
Alternate scenarios: may need brief IFR in bkw this morning.
Timing of transition to VFR may vary by an hour or so.
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 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1hrly 10 11 12 13 14 15 16 17 18 19 20 21
crw consistency h h M M h h h h h h h h
heights consistency M M M M h h h h h h h h
bkw consistency h h h M M M M h h h h h
ekn consistency h h M M M M M M M M h h
pkb consistency M M M M h h h h h h h h
ckb consistency h h h M M h h h h h h h
After 12z Tuesday...
no widespread IFR conditions expected at this time.