1. Forecasting Marine Weather
Mark Strobin
Senior Meteorologist
NWS - Monterey, CA
Saturday January 16, 2010

2. The forecast process
Tornado getting ready to touch down in Sacramento, Monday, February 22, 2005

3. Analyze Current Conditions http://www.nrlmry.navy.mil/sat_products
Satellite data
- clouds and
precipitation
IR Imagery

4. Analyze Current Conditions http://www.nrlmry.navy.mil/sat_products
Satellite data
- clouds and
precipitation
Visible Imagery

5. Analyze Current Conditions http://www.jpl.nasa.gov Satellite data
derived
winds
(QuikSCAT)

6. Analyze
Current
Conditions
Buoy reports
-text format

7. Analyze Current Conditions http://www.ndbc.noaa.gov Buoy reports -NDBC
web site

8. Analyze Current Conditions Buoy reports -NDBC web site, detailed buoy
info

9. Analyze Current Conditions Buoy reports -NDBC web site, detailed wave
summary

10. Analyze
Current
Conditions
Buoy reports
and local swell
models

11. Analyze
Current
Conditions
Bay
Reports

12. Farallon Island Observations
Here is a link to automated Farallon Island Weather, updated hourly.
Box on the right, nwsli id, enter fndc1 Then press go
A complicated form comes up, press Decoded Data at the bottom
Time is Zulu
UD is wind direction in degrees US wind speed UG  wind gusts UP Peak speed UR wind direction of Peak TA Temp XR relative humidity PC Precipitation

13. Analyze
Current
Conditions
Wind model

14. Analyze
Current
Conditions
Radar

15. Routine Forecast Products
NWS Forecasts
Routine Forecast Products
- Coastal Waters Forecast
- Small Craft Advisories (25-33 kt, squared seas)
- Gale (34-47 kt), Storm (48-63 kt),
Hurricane Force (63+ kt) Wind Warnings
Non-Routine Forecast Products
- Special Marine Warnings
- Marine Weather Statements
- High Surf Advisories
- Coastal Flood Warnings, etc.

16. Routine Forecast Products
Coastal Waters Forecast
four coastal waters zones and
two bay zones
1. Pt Arena to Pt Reyes out 10 nm
2. Pt Reyes to Pigeon Pt out to 10 nm
3. Pt Arena to Pigeon Pt nm offshore
4. Pigeon Pt to Pt Pinos out 10 nm
5. pt pinos to Pt Piedras Blancas out to 10 nm
6. Pigeon Pt to Pt Piedras Blancas nm offshore
7. San Francisco, San Pablo, Suisun Bays and the West Delta Delta
8. Monterey Bay

17. National Weather Service
Our Forecast Area
National Weather Service
Forecast Office
San Francisco Bay Area
Public and Marine
Forecast Zones

18. Forecast elements in coastal waters forecast
Wind speed and direction
Wind waves
Swell height and direction
Swell period (only for first 36 hours)
Significant weather (only for first three days)
Synopsis of current weather situation
Forecast periods are 12 hours long for first three days and then 24 hours long for days 4-5

19. Advisory and warning criteria
Small Craft Advisory: knots
Gale Warning: knots
Storm Warning: knots
Hurricane Force: knots or greater
Small Craft Advisory: Square seas or steeper
High Surf Advisory: foot waves

20. San Francisco Bar

21. San Francisco Bar

22. San Francisco Bar

23. San Francisco Bar Forecast
Small Craft Advisory for Rough Bar issued if seas are 10 feet or greater on the Bar.
.....SAN FRANCISCO BAR/FOURFATHOM BANK FORECAST IN THE DEEP WATER CHANNEL...COMBINED SEAS 6 TO 8 FT THIS EVENING THROUGH SATURDAY. ACROSS THE BAR...COMBINED SEAS 6 TO 8 FT THIS EVENING THROUGH SATURDAY. SEAS MOSTLY WIND WAVE THIS EVENING...TRANSITIONING TO MOSTLY SWELL BY LATE TONIGHT. SEAS OCCASIONALLY TO 9 FEET DURING MAXIMUM EBB CURRENT OF 1.4 KT AT 2:45 AM SATURDAY MORNING AND AGAIN DURING MAXIMUM EBB CURRENT OF 2.4 KT AT 2:19 PM SATURDAY AFTERNOON.

24. Non-Routine Advisory Products
High Surf Advisory
- issued when significant wave heights of feet or greater are expected
- research underway to see if criteria should
be modified to include wave period.
(i.e. 14 ft swell with a 19 second period has
a much larger impact on the coast than a
16 ft swell with a 9 second period)

25. Non-Routine Advisory Products
High Surf Warning
- issued when significant wave heights of feet or greater are expected

26. Non-Routine Advisory Products
Marine Weather Statement
- issued as a “heads up” for hazardous weather
- large-scale Pacific storms approaching the
California coast
- unusually high surf and/or rip currents
- organized areas of non-severe thunderstorms
- other hazardous weather (dense fog, etc.)

27. Non-Routine Warning Products
Special Marine Warnings
A severe local storm warning informing
mariners of short term hazards not covered
by existing forecasts and warnings.
Usually for convective storms.
- waterspouts
- funnel clouds
- severe thunderstorm (i.e., ¾ inch hail or winds >34 kts)
Rare in California, but can occur.

28. Forecast dissemination
Dissemination methods
- NOAA Weather Radio
- Internet
- Coastal Waters (out to 60 nautical miles)
- Offshore Waters ( nautical miles and beyond)
- Others (info at
Radiofax
PORTS
EMWIN/EDIS
NOAA Weather Wire Services

29. NOAA Weather Radio transmitters
Big Rock Ridge – marine radio KDX 54

30. Forecast dissemination http://www.weather.gov/sanfrancisco Local NWS
Website

31. Forecast
dissemination
Digital (Graphical)
Forecast

32. Questions?
Contact info:
Mark Strobin