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000
FXUS61 KCTP 221816
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
216 PM EDT Thu Jun 22 2017

.SYNOPSIS...
A warm front will move through the region today, bringing a
return to warmer and much more humid conditions this afternoon
right through Friday night. A cold front will push east across
the region during the morning or early afternoon hours Saturday,
followed by drier and cooler air with comfortable humidity that
will last through much of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...

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An area of showers and thunderstorms extends from east of BUF
down into NERN Ohio. The HRRR takes this ESE across the area
mainly north of I-80 through late afternoon before depicting it
as becoming more scattered and disorganized.

Dewpoints have surged into the mid and upper 60s rather quickly
with the approach and passage of the diffuse warm front. We
will stay in the soupy airmass for at least the next 36-48
hours before drier air returns to the region.

SPC has much of the northern portion of the region under a
Marginal Risk. Instability in the area of the Marginal Risk is
limited at best as of mid day, but model guidance does show the
development of at least moderate CAPE and shear over much of
the western part of the state as the afternoon warms up, and
with dewpoints climbing this looks reasonable.

RAP depicts 0-1km EHIs between 1 and 1.5 m2/s2 across much of
the NW part of my CWA into the evening, so the potential exists
for stronger storms to rotate. SPC addressed the convection
developing over the area and this tendency for rotation, but at
this time a watch is not likely.

The biggest threat over the next 36-48 hours will be for heavy
flooding rains as we see an almost classic set up for a PRE
event developing over the NERN US. Any localized heavy showers
and thunderstorms today will lay the groundwork/lower FFG values
and additional and potentially training convection that will
occur Friday through Friday night as moisture from Tropical
Storm Cindy surges into the NE US.

Moisture will continue to increase ahead of the remnants of TS
Cindy that are surging NE out of the Gulf States. PWATs are
forecast to increase to between 1-4 sigma by daybreak Friday and
continue into Saturday morning.

By late tonight rain and embedded heavy thunderstorms should be
overspreading my southern zones. Any decision on Flood Watches
will be made by later shifts.
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&&

.SHORT TERM /FRIDAY/...

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Friday into Friday night will be the most active weather period
of the next 7 days as increasing large scale lift/vertical
shear ahead of a potent northern stream trough interacts with
the deep tropical moisture and high PWAT air in place across
the state. WPC has a Slight to Moderate Risk of heavy flooding
rains for our entire forecast area. The set up is pretty much
right out of Junker`s heavy rain manual with tropical moisture
getting funneled up into the westerlies and into what is
forecast to be a large jet entrance region from the the Midwest
into the eastern Gr Lakes.

Basin average rainfall for the 48 hour period today through
early Saturday calls for widespread amounts of an inch of more,
with SWRN areas seeing between 1.5 and 2.25 inches. Training
showers and storms in this moisture rich environment (PWATs well
in excess of 2") could quickly increase the Flash Flood
potential Friday into Friday night.
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&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
From a large scale perspective, the medium range forecast will
feature a seasonably strong/amplified upper trough settling over
the Northeast U.S into next week.

Expect moisture/rainfall associated with the remnants of TS
Cindy to exit the area by the mid to late morning hours
Saturday.

Drier, low PW air arrives for the late morning and afternoon
hours Saturday and lasts through the weekend. This should
translate into comfortable, low- humidity conditions with
temperatures near to slightly below late June climatology.
Precipitation opportunities will be modulated by several
shortwave impulses which have low predictability at this range.
Any rains would be generally scattered and on the lighter side
given overall lack of deep layer moisture. 21/12z GEFS shows PW
values remaining below average into midweek.

Temperatures should stay on the cooler side of climo through
midweek as the upper level trough shifts east of the area. FWIW
the GFS is more bullish vs. EC on heights rebounding/building SE
U.S. upper ridging into the second half of next week. That
said, there is general agreement in a modest warming trend later
next week as the trough moves out and heights return to normal.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...

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Widespread VFR exists as of 18Z.

An area of showers/thunderstorms is dropping ESE through the
northern mountains. BFD will be the most likely to experience
brief reductions as the convection affects the airfield.
Elsewhere VFR will continue into the evening with hit and miss
showers and storms causing localized reductions.

There will be a better chance for more widespread IFR
conditions to develop tonight and tomorrow as rain and embedded
thunderstorms from the remnants of TS Cindy overspreads the
region.


.OUTLOOK...

Sat-Sun...Mainly VFR

Mon-Tue...Mainly VFR. Chc SHRA/TSRA.
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&&

.EQUIPMENT...
KCCX radar will be offline for approximately 4 days starting
Saturday, June 24th for technicians to install the first of 4
major service-life extension upgrades. The work on the radar has
been scheduled to minimize potential impacts to operations and
will be delayed if hazardous weather is forecast.

&&

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

&&

$$
SYNOPSIS...La Corte
NEAR TERM...La Corte
SHORT TERM...La Corte
LONG TERM...Lambert/Steinbugl
AVIATION...La Corte
EQUIPMENT...