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TRANSCRIPT
National Weather Service Flood Forecasting and Warning Program
Charles RossService Hydrologist
NWS State College, PAMarch 16th, 2021
Harrisburg, City Island, March 1963
National Weather ServiceWater PredictionsforLife Decisions
Thanks For attending !
Topics covered today• PA Weather/Hydrology Review• NWS Hydrologic Program Overview• Real time river and flood mapping and information on the web• Flood Safety Week Coming Up
Let’s keep this interactive and laid back• Ask questions!!• Comments welcome
National Weather ServiceWater PredictionsforLife Decisions
PA Weather Classified as a humid continental climate
• Hot and humid summers, cold winters
Precipitation is fairly spaced out throughout the year• July wettest, February snowiest
It can flood any time of the year• Heavy rain from thunderstorms, tropics, stalled fronts• Snowmelt / Ice can contribute• Seasonal factors: Frozen ground, greenup, saturation, etc
National Weather ServiceWater PredictionsforLife Decisions
National Weather ServiceWater PredictionsforLife Decisions
Poll Question 1 What was the wettest year on record for
Pennsylvania?
A. 1972B. 2011C. 1996D. 2018
National Weather ServiceWater PredictionsforLife Decisions
National Weather ServiceWater PredictionsforLife Decisions
PA Hydrology
National Weather ServiceWater PredictionsforLife Decisions
Poll Question 2 Which has the largest mean annual flow?
A. Delaware River at Trenton (Philadelphia area)B. Susquehanna River at HarrisburgC. Ohio River at Sewickley (Pittsburgh area)
National Weather ServiceWater PredictionsforLife Decisions
National Weather ServiceWater PredictionsforLife Decisions
Types of Flooding in PA● Flash Flooding - A rapid and extreme flow of high water into a normally dry
area, or a rapid water level rise in a stream or creek○ Mostly from heavy rain in the spring and summer○ Tropical storms○ Ice Jams in winter○ Dam Break (rare, but can happen)
● River Flooding - Occurs when river levels rise and overflow their banks or the edges of a river or stream and inundate areas that are normally dry.○ Very common in Pennsylvania
National Weather ServiceWater PredictionsforLife Decisions
Our Office in State College
National Weather ServiceWater PredictionsforLife Decisions
NWS Offices Nationwide
National Weather ServiceWater PredictionsforLife Decisions
NWS River Forecast Centers
National Weather ServiceWater PredictionsforLife Decisions
National Water Center
National Weather ServiceWater PredictionsforLife Decisions
NWS Data on the Web
National Weather ServiceWater PredictionsforLife Decisions
River Gage Data
AHPS is the source
water.weather.gov
National Weather ServiceWater PredictionsforLife Decisions
River Forecast Centers
Two RFCs service Pennsylvania:-Ohio River Forecast Center● https://www.weather.gov/ohrfc/● Ohio River Basin
-Middle Atlantic River Forecast Center● https://www.weather.gov/marfc/● Susquehanna and Delaware Basins
National Weather ServiceWater PredictionsforLife Decisions
National Water Model● 4 components to this national model
○ Analysis○ Short Range 18-hour forecast○ Medium Range○ Long Range
● 2.7 million stream reaches! ● 3.6 million water miles● 700x spatial density of forecasts provided
today● PA centric link
National Weather ServiceWater PredictionsforLife Decisions
Interesting NWS Hydro Links
● Flood Inundation Mapping ○ Overview Video○ https://water.weather.gov/ahps/inundation.php
● NOAA Atlas 14 Precipitation Frequency Estimates○ Historical frequency of heavy rain events○ https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_map_cont.html
● 1-stop Gage Analysis page○ Edit the URL below to enter NWSLID or USGS gage number○ https://www.weather.gov/source/aprfc/gageAnalysis.html?site=harp1
National Weather ServiceWater PredictionsforLife Decisions
National Weather ServiceWater PredictionsforLife Decisions
Flood Safety Week Is Next Week
● NWS Planning a big push on flood safety this year○ Daily Social Media posts on our Facebook and Twitter Page
■ https://www.facebook.com/NWSStateCollege/■ https://twitter.com/NWSStateCollege
○ Two livestream virtual lectures on Pennsylvania flood safety■ Monday, March 22, at 7PM: https://attendee.gotowebinar.com/register/6920019834983037710
■ Wednesday, March 24, at 11AM: https://attendee.gotowebinar.com/register/7633099305084184078
National Weather ServiceWater PredictionsforLife Decisions
National Weather ServiceWater PredictionsforLife Decisions
National Weather ServiceWater PredictionsforLife Decisions
National Weather ServiceWater PredictionsforLife Decisions
National Weather ServiceWater PredictionsforLife Decisions
National Weather ServiceWater PredictionsforLife Decisions
Thank you for attending!
Contact Info:Charles RossService Hydrologist, NWS State College [email protected](814) 954-6387