Flood Potential Outlook
Issued by NWS State College, PA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5
503
FGUS71 KCTP 161844
ESFCTP
PAC001-009-013-021-023-027-033-035-037-041-043-047-055-057-061-067-
071-075-081-083-087-093-097-099-105-107-109-111-113-117-119-123-133-
181845-

Winter/Spring Flood Potential Outlook
National Weather Service State College PA
144 PM EST Thu Feb 16 2017

...WINTER/SPRING FLOOD POTENTIAL OUTLOOK ISSUED FEBRUARY 16 2017...

INTRODUCTION.

During the winter and spring...the National Weather Service issues a
series of winter and spring Flood Potential Outlooks. These outlooks
estimate the potential for river flooding (not flash flooding)
across central Pennsylvania based on a current assessment of
hydrometeorological factors which contribute to river flooding.
Across central Pennsylvania these factors include recent
precipitation...soil moisture...snow cover and snow water
equivalent...river ice...streamflows...future weather conditions and
other. This outlook does not address the severity or extent of any
future river flooding.

This outlook covers the Susquehanna River Basin including the West
Branch...Juniata...and much of the Middle and Lower Susquehanna
Valley. Also covered are portions of the Upper and Lower Allegheny
Basins...including areas from Warren and McKean Counties in the
south.

This outlook is valid Thursday February 16 through Thursday March 2,
2017.

In central Pennsylvania...heavy rainfall is the primary factor which
leads to river flooding. It is important to note that heavy rainfall
can rapidly cause river flooding any time of the year...even when
overall river flood potential is considered low or below average.

Detailed Discussion.

Two week river flood potential...The current potential for river
flooding is average.

Current flooding...None. No flooding is occurring in the region at
this time.

Recent precipitation...Variable.

Precipitation within the State College Forecast area during the last
30 days (January 16th - February 15th) is variable across the
region...with the eastern third of the region seeing below average
precipitation and the western two thirds of the region at or above average.

Snow conditions...Below Average.

Most of the northern half of the area has snow on the ground, as well
as the Laurel Highlands. Snow depths range from 1 to 10 inches with
the deepest snow pack over northern Warren and McKean Counties. Snow
water equivalents are generally under one inch which is below average
for mid February.

Snow data and information sources include the NOAA/NWS Operational
Hydrologic Remote Sensing Center (www.nohrsc.noaa.gov)...the US Army
Corps of Engineers...NWS Cooperative Observers...the Community Rain,
Hail and Snow Network (COCORAHS) and others. Snow depth and basin
average water equivalent estimates can be seen at
www.erh.noaa.gov/er/marfc and www.nohrsc.noaa.gov .

River ice...Below average.
All rivers and streams are open and running with only spotty ice
coverage...which is unusual for mid February. Follow river ice
conditions at http://erh.noaa.gov/ctp/hydro/riverice/index.php .

Stream flow conditions...Average and Above Average.
Due to recent snow melt and rainfall streamflows are above average
across western portions while closer to normal in the east.

Real time water data is available from the United State Geological
Survey by visiting http://water.usgs.gov .

Soil moisture conditions...Average.
The latest soil moisture reports show that most of the region is
reporting near average moisture conditions. The February 15, 2017
chart (found at www.cpc.ncep.noaa.gov/products/analysis_monitoring/
regional_monitorin g/palmer.gif) suggest deep soils across the area
contain moisture that is fairly close to normal for this time of year
with soil moisture levels improving over the northern half of
Pennsylvania. The most recent version (February , 2017) of the US
Drought Monitor chart does show eastern portions of the area
experiencing abnormally dry to moderately dry conditions
(http://droughtmonitor.unl.edu).

Moisture monitoring charts from NOAA`s Climate Prediction Centre can
be found at:
www.cpc.ncep.noaa.gov/products/soilmst_monitoring/us/soilmst/
soilmst.shtml and www.drought.gov .

Ground Water...Variable.
Monitoring wells are all at or above normal for western areas while
southern and eastern areas of the region are below or even much below
average...corresponding to where drought conditions are being
observed.

Current ground water conditions based on a 30 day moving average can
be found at http://pa.water.usgs.gov/monitor/gw/index.html .

Reservoir conditions...Average.
Most water supply reservoirs within central Pennsylvania are holding
average storage for this time of year...as are most flood control
reservoirs.

Future weather conditions...A dry and very warm weather pattern will
develop over the region beginning Friday and continue through much of
next week. Little precipitation is expected and temperatures will be
move above normal through next Friday. A return to more seasonal
temperatures and the return of precipitation is expected by late next
week and the week after. Longer range weather outlooks can be viewed
at www.cpc.ncep.noaa.gov .

Advanced Hydrologic Prediction Service (AHPS)...Normal.
Another tool used to assess the potential for river flooding is the
Advanced Hydrologic Prediction Service...AHPS. AHPS generates
probabilistic river forecasts based on current basin
conditions...including river levels...soil moisture...extent and
condition of any snow pack...along with 50 years of history
temperatures and precipitation data. For this outlook period...AHPS
indicates that the likelihood of river flooding is near average
compared to what has been observed during this same time period
across small river basins in central Pennsylvania. River information
can be found at water.weather.gov .

Summary of flood potential February 14 to March 2, 2017: The
regional flood potential is average for the next couple of
weeks. While no flooding is expected next week...a return to more
active weather is expected for week two in this outlook. The lack of
deep snow pack and lack of river ice would work against the threat
of flooding. Heavy rainfall would be required to cause river
flooding.

Overview: Current Flooding...None.
Recent Precipitation...Variable.
Snow Conditions...Below average.
River Ice...Below Average.
Stream Flow Conditions...Average.
Soil Moisture Conditions...Average.
Ground Water...Variable.
Reservoir Conditions...Average.
AHPS...Average.
Overall Flood Potential...Average.

The next flood potential outlook will be issued on Thursday March 2nd.

Other hydrometeorological information can be found by visiting the
State College Internet Homepage at http://weather.gov/ctp .

$$

CR



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.