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NOAA’s National Weather Service New York, NY Winter Storm Briefing January 24, 2011 2:30 pm. Surface Weather Map Jan 24 at 10 am Low Pressure Developing Gulf Of Mexico. Track Forecasts Highly Uncertain. Huge Differences Continue in Forecast Models. NAM Model. GFS Model.
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NOAA’s National Weather ServiceNew York, NYWinter Storm BriefingJanuary 24, 20112:30 pm
Surface Weather MapJan 24 at 10 amLow Pressure Developing Gulf Of Mexico
Huge Differences Continuein Forecast Models NAM Model GFS Model
Watch/Warning Program • Outlooks (Get Ready) • Potential for significant events up to 7 days in advance • Forecaster confidence around 30% • Watches (Get Set) • Issued up to 48 hours in advance • Forecaster confidence around 50% • Warnings/Advisories (Go) • Issued 0-24 hours in advance • Forecaster confidence at least 80 percent
Winter Storm Outlook Continued for this Afternoon’s Forecast Update 1 in 3 Chance of a Significant Winter Storm Wednesday through Thursday
Potential Storm Impacts Heavy Snow – Highest Threat W and N of NYC Heavy Rain – Highest Threat SE CT and Twin Forks of Long Island Rain Changing to Snow Including Freezing Rain– Areas Between Potential for Strong Winds – Highest along the Coast Potential for Moderate Beach Erosion and Minor Tidal Flooding
Potential for Flooding Highest Eastern Suffolk County and SE CT - Up to 2.5 inches Liquid in Snow Pack - Heavy Weight on Weaker Flat Roofs could cause Collapses - Heavy Rain will Runoff over Frozen Ground causing Urban Flooding
HPC Probability of Freezing Rain .01 Inch Up to .25 or ¼-Inch
Potential for Strong Winds Strong NE Winds 20-30 G 40 MPH Developing Wed Afternoon Strong N-NW Winds 25-35 G 50 MPH Possible Wednesday Night Strong NW-W Winds 15-25 G 30 MPH Thursday
Seasonably ColdFriday and Saturday Temperatures Averaging Around 5 Degrees Below Normal - NO ADDITIONAL BIG Storms Forecast