Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 201842
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
242 PM EDT Tue Jun 20 2017

.SYNOPSIS...
Weak high pressure will slide south of the commonwealth through
Wednesday afternoon. Weak upper air disturbances will produce
isolated showers across the northwest late tonight and over the
rest of central PA on Wednesday afternoon, although most of the
time with be fair and dry.

A deep upper level trough will approach the region later this
week and draw a plume of deep tropical moisture north from the
Gulf Coast region. This will bring increasing showers and
thunderstorms back to the state from late Thursday into early
Saturday. Drier and cooler conditions will return later Sunday
into next Monday.

&&

.NEAR TERM /THROUGH TONIGHT/...
A weak ridge of high pressure at the surface will keep fair
conditions over most of central PA tonight, with mostly clear
skies central and south. One of several upper air disturbances
rotating around quasistationary low over eastern Canada will
push a band of weakening showers into northwest PA late tonight
into early Wednesday, the first hint of return flow as flat
upper ridging evolves over the Ohio Valley and eastern GLAKS
through mid week.

Light SW wind tonight and rather strong radiational cooling
will bring some areas of valley fog across portions of the
central and north central mountains.

Mins shortly after sunrise Wed will vary from the chilly L50s
near and to the east of KBFD, to the u50s and l60s throughout
the Susq Valley.

&&

.SHORT TERM /WEDNESDAY/...
Additional upper trofs traverse central and north central PA on
Wednesday as deep layer moisture slowly begins to increase... an
additional sign of this moderating airmass. This will bring
isolated to scattered showers and a slight chance of thunder in
the afternoon, but most areas will remain dry and quite
comfortable for mid to late June. Highs will range from the
lower 70s north to the lower 80s southeast.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Still looks like a strong push of warm and humid air from the SW
and West for later Thursday into Friday, with the next chc for
showers and isolated-scattered tsra will come Friday afternoon
into saturday morning. The best chc to see a period of mdtly
heavy rain will be across the western and southern counties of
the state.

The cold front helping to trigger the showers and
isolated-scattered TSRA drops just to the south of PA Saturday
afternoon and night and becomes quasi-stnry and washes-out as
the shortwave energy support it races away across New England
and a deepening trough moves from the Northern Rockies to the
Midwest states as the deep layer zonal flow backs to the SW.

It gets quite difficult to push cold fronts much further south
now, as we head into summer.

EC and other models show a rather strong low for late June
tracking across the Great Lakes on Sunday. Another round
of showers and storms.

Rather strong cold advection for next Monday.

Will have to watch the Golf of Mexico to see if moisture
will be pulled northward later in the week ahead of any
of the fast moving lows tracking across the lakes.

Overall just minor changes made to the extended package.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
Mostly VFR through tonight. A few showers/isolated tstorm
possible this afternoon over the NW mtns in proximity to a
trough brushing that region.

Outside of the isolated tstorm risk around BFD, biggest impact
today will be breezy westerly winds increasing to around 15 mph
with gusts to 25 mph. These diminish to 8 mph or less by early
evening.


.OUTLOOK...

Wed...Mostly VFR conditions. Isold to sct SHRA poss mainly
central and north

Thu...Sct SHRA and Iso TSRA N.

Fri...Cig restrictions poss west. SHRA likely / chance TSRA.

Sat...Chance for SHRA/TSRA south. Restrictions poss early.

Sun...Improving conds...mainly VFR.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...DeVoir
NEAR TERM...DeVoir
SHORT TERM...DeVoir
LONG TERM...La Corte
AVIATION...DeVoir/RXR



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