Area forecast discussion
National Weather Service State College PA
258 PM EDT Sat may 18 2013
Synopsis...
a wavy frontal boundary extending from the upper Midwest through
the Ohio Valley and across the central Appalachians into southern
Middle-Atlantic States will slowly return northward as a warm front
late Sunday into Monday. The warm front will then stall out across
upstate New York and New England before sinking back to the south
and oscillating over Pennsylvania into the middle of next week.
The front should finally push south of the area by late next week
or early in the weekend...as a large Canadian high pressure system
drops southeast into the Great Lakes region. Overall expect a
prolonged stretch of unsettled weather over the next several days.
Temperatures will be more typical of early Summer by Tuesday...
before cooling below normal by next weekend.
&&
Near term /until 11 PM this evening/...
did cut back some on probability of precipitation across the SW on the 130 PM
update...but now storms are just to the west of the County Warning Area...
thus adjusted some more.
Most of the area is rather cloudy...not real high dewpoints...
thus only have thunder in far SW areas.
No major changes at this point.
&&
Short term /11 PM this evening through 6 PM Sunday/...
seems like a no-brainer to forecast thick lower clouds tonight over
much of the area...and the upslope flow will create patchy light
rain or drizzle over much of the area through the night.
About the time of year to see higher dewpoints. Often can see
higher quantitative precipitation forecast amts across the far southeast areas...especially Lancaster
County...mainly late at night...but in this case...did not go
too high...given that I normally like to see forecast dewpoints
higher.
Did not change temperatures much...just a tad higher across the west.
&&
Long term /Sunday night through Saturday/...
The medium range guidance continues to advertise a rather
unsettled period of time for much of the upcoming week.
We are and will remain basically under a mean upper ridge...but
the problem will be a weak frontal system that will be meandering
around central PA for much of the time into late week. So while
there support aloft for organized precipitation will be confined to small
scale features that will be hard to see more than a day or two
down the Road...the low level forcing and increasing
humidity/instability will bring several chances for mainly diurnal
showers and thunderstorms.
The forecast has a lot of redundancy in it starting tomorrow
night..implying a prolonged period of rain/storms. The reality is
likely to be more like a period of mainly cloudy skies but with
sunny breaks during the day...along with showers that will be
most likely in the afternoon and evening. Where the front will be
on any given day will have much to do with mesoscale influences
from any convection that manages to form. At this range all that
can be said is the boundary will be hanging around nearby.
Despite ample cloudcover and the chances for rain...temperatures
should remain above normal until at least late week when guidance
suggests we finally see a cold front move through ushering in
some cooler and drier conditions.
&&
Aviation /19z Saturday through Thursday/...
5-18/18z...
VFR flying will continue this afternoon across most of
the area... with broken-overcast Alto cumulus bases around 7-10kft above ground level.
However...just starting to see lower clouds working northward from
Maryland and Virginia...into Bedford County...and now just into aoo. Strong
sun angle... similar to middle July...may try to slow down northward
edge of this area of clouds...but expect the the low-level flow to
continue veer to the southeast this afternoon and direct increasingly
moist/maritime air into the region. This will result in lowering
ceilings this evening with widespread MVFR to IFR conds expeceted tonight
into at least early Monday. Confidence is above average.
A stationary frontal boundary will lift slowly northward across
the airspace by Tuesday...which should allow for some marginal
improvement in local flying conds. A rather unsettled and potentially
wet pattern is expected during the middle to second half of next
week...with daily chance/S for convective precipitation and associated restrictions.
Outlook...
Monday...MVFR-IFR ceilings.
Tue-Thu...VFR-MVFR with scattered PM thunderstorm impacts.
&&
Ctp watches/warnings/advisories...
none.
&&
$$
Synopsis...dangelo/Martin/steinbugl
near term...dangelo/Martin
short term...dangelo/Martin
long term...la corte
aviation...Martin/steinbugl
