National Weather Service United States Department of Commerce

Severe Thunderstorm and Heavy Rainfall Potential Continues

A low pressure center tracking across the Great Lakes and its associated cold front extending across the Southern Plains will focus occasional showers and thunderstorms through tonight. A few of these thunderstorms may become severe alongside heavy rainfall that may cause flash flooding; Portions of the Southern Plains would be the greatest threat for these hazards through tonight. Read More >

Wind-Wave Correlations for Wave Forecasting

WFO Baltimore-Washington forecasts significant wave heights in the local Coastal Waters Forecast (CWF) product. Significant wave heights are the average heights (trough to crest) of the one-third highest waves. For simplicity, significant wave heights are termed waves in the WFO Baltimore-Washington CWF.

For wave forecast guidance over the Maryland portion of the Chesapeake Bay and Tidal Potomac River, WFO Baltimore-Washington uses the NWPS model. Where the NWPS domain is incomplete and beyond the NWPS time period (102 hours), wind-wave correlations are used for wave forecasts.  Those correlations are outlined below.

Generally, for wind speeds of 5 kt, waves will read "less than 1 ft." For other wind speeds, the correlations below are utilized for each marine zone. Remember that forecasts of wave heights do not include effects of wind direction relative to tidal currents. Expect higher waves when winds are blowing against tidal flow.

 

Click for the latest Coastal Waters Forecast (CWF)

 


 

POTOMAC RIVER - KEY BRIDGE TO INDIAN HEAD


[Key Bridge to Indian Head]
 
  W NW N NE E SE S SW
10 KT <1 <1 <1 <1 <1 <1 <1 <1
15 KT 1 1 1 1 1 1 1 1
20 KT 1 1 2 1 1 1 2 1
25 KT 2 2 2 2 2 2 2 2
30 KT 2 2 3 2 2 2 3 2
35 KT 2 3 3 3 2 3 3 3
40 KT 3 3 4 3 3 3 4 3
45 KT 3 4 4 4 3 4 4 4
50 KT 3 4 4 4 3 4 4 4


 

POTOMAC RIVER - INDIAN HEAD TO COBB ISLAND


[Indian Head to Cobb Island]
 
  W NW N NE E SE S SW
10 KT <1 1 <1 <1 <1 1 <1 <1
15 KT 1 1 1 1 1 1 1 1
20 KT 2 2 2 2 2 2 2 2
25 KT 2 3 2 2 2 3 2 2
30 KT 2 3 2 2 2 3 2 2
35 KT 3 3 3 3 3 3 3 3
40 KT 3 4 3 3 3 4 3 3
45 KT 3 4 4 4 3 4 4 4
50 KT 4 5 4 4 4 5 4 4


 

POTOMAC RIVER - COBB ISLAND TO SMITH POINT


[Indian Head to Cobb Island]
 
  W NW N NE E SE S SW
10 KT 1 1 < 1 < 1 1 1 < 1 < 1
15 KT 2 2 1 1 2 2 1 1
20 KT 2 3 2 1 2 3 2 1
25 KT 3 4 2 2 3 4 2 3
30 KT 3 5 3 2 3 5 3 2
35 KT 4 5 3 3 4 5 3 3
40 KT 4 6 4 3 4 6 4 3
45 KT 5 6 4 4 5 6 4 4
50 KT 5 6 4 4 5 6 4 4


 

CHESAPEAKE BAY - NORTH OF POOLES ISLAND


[Chesapeake Bay N of Pooles Island]
 
  W NW N NE E SE S SW
10 KT 1 1 1 1 1 1 1 1
15 KT 1 1 1 2 1 1 1 2
20 KT 2 2 2 2 2 2 2 2
25 KT 2 2 2 3 2 2 2 3
30 KT 3 3 3 4 3 3 3 4
35 KT 3 3 3 4 3 3 3 4
40 KT 4 4 4 5 4 4 4 5
45 KT 4 4 4 5 4 4 4 5
50 KT 5 5 5 6 5 5 5 6


 

CHESAPEAKE BAY - POOLES ISLAND TO SANDY POINT


[Chesapeake Bay - Pooles Island to Sandy Point]
 
  W NW N NE E SE S SW
10 KT 1 1 1 1 1 1 1 1
15 KT 1 2 2 2 1 2 2 2
20 KT 2 3 3 3 2 3 3 3
25 KT 2 3 4 3 2 3 4 3
30 KT 3 4 5 4 3 4 5 4
35 KT 3 4 5 4 3 4 5 4
40 KT 4 5 6 5 4 5 6 5
45 KT 4 5 6 5 4 5 6 5
50 KT 5 6 7 6 5 6 7 8


 

CHESAPEAKE BAY - SANDY POINT TO NORTH BEACH


[Chesapeake Bay - Sandy Point to North Beach]
 
  W NW N NE E SE S SW
10 KT 1 1 1 1 1 1 1 1
15 KT 1 1 2 1 1 1 2 1
20 KT 2 2 3 2 2 2 3 2
25 KT 2 3 4 3 2 3 4 3
30 KT 3 4 5 4 3 4 5 4
35 KT 3 4 5 4 3 4 5 4
40 KT 4 5 6 5 4 5 6 5
45 KT 4 5 6 5 4 5 6 5
50 KT 5 6 7 6 5 6 7 6


 

CHESAPEAKE BAY - NORTH BEACH TO DRUM POINT


[Chesapeake Bay - North Beach to Drum Point]
 
  W NW N NE E SE S SW
10 KT 1 1 1-2 1-2 1 1 1-2 1-2
15 KT 2 2 3 3 2 2 3 3
20 KT 2 2 4 3 2 2 4 3
25 KT 2 3 5 4 2 3 5 4
30 KT 3 4 6 5 3 4 6 5
35 KT 3 4 6 5 3 4 6 5
40 KT 4 5 7 6 4 5 7 6
45 KT 4 5 7 6 4 5 7 6
50 KT 5 6 7 6 5 6 7 6


 

CHESAPEAKE BAY - DRUM POINT TO SMITH POINT


[Chesapeake Bay - Drum Point to Smith Point]
 
  W NW N NE E SE S SW
10 KT 1 1-2 2 1-2 1 1-2 2 1-2
15 KT 2 2 3 2 2 2 3 2
20 KT 3 3 4 3 3 3 4 3
25 KT 4 4 5 4 4 4 5 4
30 KT 4 4 6 5 4 5 6 5
35 KT 5 5 7 6 5 6 7 6
40 KT 5 5 7 6 5 6 7 6
45 KT 6 6 8 7 6 7 8 7
50 KT 6 6 8 7 6 7 8 7