Monday, July 23, 2018, 2:10 AM EDT
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Area Forecast Discussion
Valid At
Wed, Dec 31, 7:00pm EST
FXUS61 KCTP 230607
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
207 AM EDT Mon Jul 23 2018

.SYNOPSIS...
An extended wet pattern with frequent rounds of rain will 
elevate the risk of flooding across parts of central 
Pennsylvania through at least mid-week. Drier air will try to
work in late in the week.

&&

.NEAR TERM /UNTIL 11 AM THIS MORNING/...
Firehose of moisture still directed into the region from the S.
Multiple storms rolling through the very wet area from
Harrisburg to Gettysburg needs to be watched very carefully, but
the cells are moving very fast and the torrential rain is only
there for a few minutes. Trouble is that there are more storms
to our S. Good news is on the immediate horizon for the latter
half of the night, though. Looks like a dry air, perhaps a sign
of subsidence, is right behind the few showers in MD. This lull
should last for a few hours, but showers/storms will rejuvinate
around or perhaps before sunrise. This puts us right back in the
thick of it. 

Am starting to consider yet another flood watch for the area
E of UNV and S of IPT where the rainfall has been and could
again be excessive. Will think more about this and talk to
neigbors and WPC on their thoughts.

&&

.SHORT TERM /11 AM THIS MORNING THROUGH 6 PM TUESDAY/...
*Multi-day heavy to excessive rain risk continues over parts of
 south central PA 

An extensive wet pattern will continue to raise concerns for 
flash and small stream flooding through the short term period.
The repeated rounds of showers and storms will also push many of
the smaller rivers/larger creeks in the srn half of the area to
bank full or out of their banks. Base flow is already much
higher than just back on Sat, and FFG values are just an inch or
so in the SC & SE counties. Atmospheric river set-up with deep 
layer south-southeast flow will maintain very high (2-2.25") PWs
and support intense rain rates. Much like the last 28 hours, 
though, the cell motion will be very quick, and it will take 
training to make things dangerous. But, that is getting to be a 
higher and higher probability as each day of this moisture feed 
continues.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
By Tuesday, filling upper trough off to our west will remain 
nearly stationary or even retrograde a little as strong broad 
ridge forms over the western U.S. For PA, long fetch moist 
southerly low-level flow continues for much of the week, with 
upper flow turning more SW/W. Not much to inhibit daily 
convection along this river of high PWAT air over the region, 
so very efficient precip producers that could exacerbate 
flooding situation after several days of noteworthy rains could
continue to bring potential flooding impacts through much of the
week.

Best daily chances for tstorms shifts to western/central 
sections early in the week (as ridge briefly edges in from the
east) before precip shifts eastward Thu as a cold frontal 
boundary finally pushes across the state. The weekend looks
drier yet scattered showers may persist.

Though it will be quite muggy, temperatures will be at or
slightly below below normal much of the week.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Firehose of moisture from south to north over the next three
days will play havoc with flight catiegories through midweek.
Expect flucuations from VFR to IFR and back in only minutes of
time as streams of moisture and associated convection move over
all airfields.

In the short term, a plume of moisture is moving north along 
the Susquehanna river. This will affect KMDT, KLNS and KIPT 
through sunrise. Airfields west of this line will have VCSH and 
visibility and ceiling reductions to MVFR in BR at times.

As heating returns during the daylight hours, -RA and TSRA will
redevelop over a majority of the area during the afternoon. 
This will diminish after sunset - only to repeat again on Monday
night and Tuesday...and points well into the future. 

.Outlook... 

Tue-Fri...Frequent showers/isolated T'storms with associated 
MVFR/IFR restrictions. TSRA most numerous in PM.

&&

.HYDROLOGY...
2 to 6 inches of rain in the past 36 hours has produced 
significant rises on small streams and creeks. An extensive wet 
pattern this week with frequent rounds of rain and daily 
downpours will elevate the risk of river (small stream/creek) 
flooding through late week.

&&

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

&&

$$
SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...Ross/Steinbugl
LONG TERM...Ross/RXR
AVIATION...Dangelo/Tyburski
HYDROLOGY...

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