Area Forecast Discussion
Issued by NWS State College, PA
FXUS61 KCTP 291525
Area Forecast Discussion
National Weather Service State College PA
1125 AM EDT WED JUN 29 2016
High pressure will bring a period of mainly dry weather with
comfortable humidity for the rest of today and Thursday. A cold-
frontal system will approach for the end of the week. The holiday
weekend is looking mainly dry with temperatures close to or just
slightly below normal for early July.
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
Strong cold advection focused near the 925mb level was helping to
strengthen the subsidence inversion and trap/maintain a shield of
bkn-ovc stratocu across much of the region outside of the
mid/lower Susq Valley. Skies in those areas late this morning were
mainly sct...but as the colder air aloft overspreads that region
through the mid afternoon hours, expect an expansion of bkn clouds
at 3.5-4.5 kft agl (which should last until 20-22z).
Based on this cloud cover, temps were blended/nudged toward
cooler 12z nam/gfs lamp guidance and trimmed by up to several deg
F from previous forecast values.
Max temps this afternoon will range from the upper 60s to around
70F across the nrn and wrn mtns, and mid 70s in the central
valleys (which is a solid several deg f or more below normal in
most areas). Temps reaching the lower 80s across the Lower Susq
Valley will be out about 2-4 deg F shy of normal.
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM THURSDAY/...
A really comfortable night is in store tonight. It is not out of
the question that the valleys in the northern mountains could get
to 40F. Most of the area will be in the 50s for mins. A few
clouds over the southern third of the area could keep temps from
getting below 60F there.
Thursday is an interesting forecast with the potential for a very
minor short wave trough to move across during the daytime. The air
is pretty dry and very few triggers will exist - other than the
hill tops. Most if not all of the area should stay dry with
little moisture. There is just a slight chance of a shower popping
up in the aftn across the srn hill tops where dewpoints will be
closer to 60F. Maxes will warm 3-6F over Wed as a light south wind
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
The mean upper trough over the Northeastern CONUS loses amplitude
through the period, as a closed 500mb low dropping southward near
James Bay shifts eastward and a subtropical ridge off the Southeast
coast retrogrades slowly westward into the Gulf of Mexico. The
large scale pattern will have a decidedly summertime look to it
as we turn the calendar page to the month of July, with the main
belt of polar westerlies located along the U.S./Canadian border
and expansive upper ridge covering the southern 1/2 of the Lower
While much of central PA could use some rain, odds are that most
of the period will be a dry one. A frontal system moving through
the area on Friday will likely provide the only opportunity for
rain (scattered showers/T-storms) until the second half of next
week /beyond July 6th/. The upside to this will be a seasonably
warm and dry period expected to last through Independence Day
with seasonal temperatures and tolerable humidity.
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
For the 15Z TAF package...have expanded the mvfr cloud deck
across the central ridge and valley taf sites...and maintained
this cloud cover into the mid afternoon...before forecasting it to
lift to mainly low-end vfr. This may be optimistic by a few hours
though. a pocket of unseasonably cool air in the low to mid levels
of the atmosphere over western penn late this morning...will drift
east across the rest of the fcst area this afternoon.
NW winds will be gusty in the upper teens to around 20 kts this
afternoon...especially across the Susq Valley where more sun and a
greater depth of vertical mixing will occur.
Next chc for showers and storms will be Thursday Night across
the east. Maybe across the entire area on Friday...if both
Thu...No sig wx expected.
Thu Night-Fri...Isold tsra impacts possible.
Sat and Sun...No sig wx expected.