Flash Flood Watch 2, NWS State College, PA

798 
WGUS61 KCTP 152147
FFACTP

Flood Watch
National Weather Service State College PA
547 PM EDT Tue May 15 2018



PAZ033>036-056-057-059-063-152300-
/O.CAN.KCTP.FF.A.0002.000000T0000Z-180516T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Somerset-Bedford-Fulton-Franklin-Perry-Dauphin-Lebanon-Cumberland-
Including the cities of Somerset, Bedford, McConnellsburg, 
Chambersburg, Newport, Harrisburg, Hershey, Lebanon, and Carlisle
547 PM EDT Tue May 15 2018

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for a portion of central Pennsylvania has
been cancelled. The threat for heavy rain has ended for the
evening. Additional rain is possible later tonight, but that is
not expected to be heavy. 

$$

PAZ064>066-160400-
/O.CON.KCTP.FF.A.0002.000000T0000Z-180516T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Adams-York-Lancaster-
Including the cities of Gettysburg, York, and Lancaster
547 PM EDT Tue May 15 2018

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL MIDNIGHT EDT
TONIGHT...

The Flash Flood Watch continues for

* A portion of central Pennsylvania, including the following 
  areas, Adams, Lancaster, and York. 

* Until midnight EDT tonight

* Localized heavy rainfall from repeat thunderstorms may produce 
  flash flooding of small streams and roads especially during 
  the evening hours. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Review flood safety and preparedness information at
weather.gov/flood.

&&

$$

936 
WGUS61 KCTP 152256
FFACTP

Flood Watch
National Weather Service State College PA
656 PM EDT Tue May 15 2018


PAZ064>066-160000-
/O.CAN.KCTP.FF.A.0002.000000T0000Z-180516T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Adams-York-Lancaster-
Including the cities of Gettysburg, York, and Lancaster
656 PM EDT Tue May 15 2018

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for a portion of central Pennsylvania has
been cancelled. 

Any additional rain this evening will be light. 

$$

Area Forecast Discussion
National Weather Service State College PA
336 AM EDT Tue May 15 2018

.SYNOPSIS...
Severe thunderstorms primarily capable of damaging winds are
forecast Tuesday afternoon and evening across parts of central
Pennsylvania. A wet weather pattern will continue through the
rest of the week as a plume of tropical moisture is advected
north into the Mid Atlantic region.

&&

.NEAR TERM /THROUGH TONIGHT/...
Isolated convection located within a zone of WAA briefly
flared up across southwest PA shortly after midnight but since
then has trended weaker into the Laurel Highlands. Quick update
to account for this activity and also added fog to the fcst per
latest obs. SPC hosted a conference call with us and offices to
the northeast concerning the day 1 severe wx outlook. There was
some consideration toward a moderate with good agreement in the
CAMS but still enough uncertainty to maintain (but expand) the
enhanced risk area. More to come on this later...

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
Surface low pressure (1004-1006 MB) will be located across the
eastern end of Lake Erie at 12Z with a cold front training SW
across Lake Erie/Ohio and a warm front SE twd the Poconos. SFC
trough extending south of the low will become enhanced from lee-
side stretching over the Susq Valley during the late
morning/afternoon hours Tuesday. Warm/humid air will supply and
a 1-2 sigma swrly wind at 850 mb on the GEFS will greatly
enhance EHIs to 2-3 m2/s2 as noted by the 18Z RAP from KIPT to
KEG and KMDT.

All but the NW part of of our CWA is in SPC's DAY 2 Slight Risk
area which looks very reasonable.

Temps Tuesday will be a few to several deg F warmer than Monday,
with afternoon highs ranging from the mid to upper 70s across
the Northern and Western Mtns respectively, to the mid and upper
80s over the SE half of the forecast area.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
A persistent flow of subtropical moisture interacting with a
quasi-stationary frontal system will keep conditions soggy over
the region for the foreseeable future. The front will wag north
and south for the next several days bringing periods of showers
and thunderstorms with very little chance of any 12 hour period
remaining dry in any one location. Proximity of drier air mass
and high pressure to the north over southern Canada means that
drier air will filter southward into far northern PA from time
to time, giving at least some chance of periodic drier periods
this week, but the main story is for daily chances of showers
and thunderstorms until further notice. The Thursday night into
Friday timeframe looks particularly wet as deep layer moisture
surges (PW near 2.0") thanks to amplification of the offshore
upper ridge coupled with a nearly stationary upper trough over
the central plains. This will direct copious subtropical
moisture northward into the eastern GLAKS and set the stage for
locally heavy rains and potential flooding given what will have
been a very wet week by that time.

Temperatures should be above seasonal climate averages this week
with a muggy summertime/humid feel given dewpoints in the 60s.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
07Z regional radar loop showing a few isolated
showers/thunderstorms popping up along approaching warm front,
running from northeast Ohio to northern Virginia. As the front
moves northeast, there could be a a few showers or thunderstorms
across central Pa overnight, mainly over the northwest part of
the state. Any shower or storm could be accompanied by a brief
vis reduction. Model soundings and SREF prob charts also
indicate the possibility (<50pct) for a brief period of IFR cigs
in the vicinity of KBFD early Tuesday morning associated with
passage of the front.

Perhaps the biggest concern overnight will be the possibility of
fog across eastern Pa. Dewpoint depressions already low in this
area, and when skies clear expect fog to develop between 05Z-08Z.
Latest SREF prob charts and NAMNest indicate the Susquehanna
Valley (especially KIPT/KLNS) is the area most likely to
experience significant vis reductions early Tuesday morning.

Any fog should mix out by 13Z-14Z over eastern Pa, followed by
widespread VFR conditions for late morning. A cold front will
push south across the region Tuesday afternoon, accompanied in
many locations by a round of strong to potentially severe
thunderstorms, with briefly reduced cigs/vsbys and possible strong
wind gusts.

Outlook...

Wed-Thu...Rain/low cigs possible, mainly southern Pa.

Fri...Rain/low cigs likely.

Sat...Rain/low cigs possible.

&&

.HYDROLOGY...
Static pattern. Soils continue to get wetter as each days'
storms yield stripes of 1+" rainfall. PWATs hang in the 35-40mm
(1.5") range today and Tues before inching (pun) down to only an
inch on Wed-Thurs. They ramp up and get even higher than today
on Fri-Sat as a surge of tropical moisture flows in.

The showers/storms today will be moving along quickly with the
fast flow in mid-levels, but many will take the same path as the
last few days...that being across the SW/SCENT mtns of the
state where Flash Flood guidance is the lowest with hourly
values an inch or less.

A wider swath of heavier rain is expected on Tues aftn/evening
- but generally over areas which have received less rainfall
than the SWrn third of the CWA. Adding this up, it seems like
the chance for flash flooding is going to be higher on Tuesday
across a larger part of the CWA, but is still low enough at this
time to not post a flood watch. Chatting with neighboring
offices yields very similar thoughts.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch from 2 PM EDT this afternoon through this
evening for PAZ033>036-056-057-059-063>066.

&&

SYNOPSIS...Steinbugl
NEAR TERM...Steinbugl
SHORT TERM...Steinbugl
LONG TERM...DeVoir
AVIATION...Fitzgerald/Gartner
HYDROLOGY...

Hazardous Weather Outlook
National Weather Service State College PA
423 PM EDT Mon May 14 2018

PAZ004>006-010-011-037-152030-
Warren-McKean-Potter-Elk-Cameron-Tioga-
423 PM EDT Mon May 14 2018

This Hazardous Weather Outlook is for central Pennsylvania.

.DAY ONE...Tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

PAZ012-017>019-024>028-033>036-041-042-045-046-049>053-056>059-
063>066-152030-
Northern Clinton-Clearfield-Northern Centre-Southern Centre-Cambria-
Blair-Huntingdon-Mifflin-Juniata-Somerset-Bedford-Fulton-Franklin-
Northern Lycoming-Sullivan-Southern Clinton-Southern Lycoming-Union-
Snyder-Montour-Northumberland-Columbia-Perry-Dauphin-Schuylkill-
Lebanon-Cumberland-Adams-York-Lancaster-
423 PM EDT Mon May 14 2018

This Hazardous Weather Outlook is for central Pennsylvania.

.DAY ONE...Tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Another round or two of strong to locally severe thunderstorms is
expected Tuesday afternoon and evening. The main severe weather
threat is in the form of localized damaging straight-line wind gusts
and isolated instances of large hail, one inch in diameter or
greater.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.