We’ve had an ongoing conversation about the forecasting process over the years with Dave Feit, who runs the Marine Prediction Center. Recently Dave pointed us to a new (to us) resource, which is a technical discussion of the North Atlantic and Pacific forecasts. This includes how the weather models are behaving, and what various scenarios are for the different forecast products. These “interpretations” are done in a sort of shorthand.

These messages were originally developed for dissemination to National Weather Service employees via teletype (50baud!) and so they have a lot of contracted words (acronyms). For the most part, these are words where the vowels have been omitted, and after you’ve read a few, they will start to make sense. For example “dcrsg” = “decreasing”, an “cdfnt” = “cold front”.

Some other acronyms often used are:

ASCD = associated ATTM = at the moment

ETA = Eta model CAA = cold air advection

HPC = Hydrometeorological Prediction Center

If you read through a couple of messages, and at the same time watch the various surface and upper level faxes, you will begin to get a feel for what the forecasters in the Marine Prediction Center are watching.

This is valuable now, before you go, as a learning experience. And it’s incredibly useful just before you head offshore.

At the top of the Marine Prediction Center Forecast Products page you’ll see links for Atlantic Forecast Discussion and and Pacific Forecast Discussion , as well as Gulf, Caribbean, and DSW Atlantic Forecast Discussion .

When you click on one of these, a file will download which you can then open and read in your word processor. (We open ours in Microsoft Word).

You will also find on this page various text forecasts which are broadcast on ssb, vhf, and via fax.

Following is an example of a recent Marine Interpretation Message for the Atlantic:

MARINE INTERPRETATION MESSAGE NATIONAL WEATHER SERVICE WASHINGTON DC

MARINE PREDICTION CENTER/MARINE FORECAST BRANCH 0116 AM EDT Oct 18 2001

FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT WEATHER FOR NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N:

Ref. AWIPS…Surface/NCEP Graphics/Surface Obs/WATL wind/wave.

COLD POCKET MAKING WAY ACRS NEW ENGLAND AND NRN WATERS WITH 44025 29 KT G 35…BUZM3…38 KT G 44 KT AT 03Z. SEAS HAVE CONTINUED TO NOSE UP TO 13 FT AT 44011…A LTL AHEAD OF WAVEWATCH. CONSIDERING EXTENDING GALE WARNING INTO MORNING HOURS GULF OF MAINE AND GEORGES BANK…WILL MAKE FINAL DECISION S OF NEW ENGLAND AS WHETHER TO HAVE GALE FOR REMAINDER OF NIGHT OR A BRIEF PORTION OF MORNING.

SOME MINOR DIFFERENCES SHORT TERM AS PER AVN AND ETA WITH BIT OF A SURGE EARLY THIS MORNING ACRS THE NORTHERN CANYONS TO HATTERAS CANYON AS HIGH BUILDS OUT. AVN A TAD STRONGER THIS RUN WITH ETA CONSISTENT WITH 18Z RUN. CURRENT FCST HAS THIS HANDLED AND WILL LEAVE AS IS…MAY CONSIDER A REMAINDER OF NIGHT FOR HUDSON TO HATTERAS CANYON.

NE FLOW S OF HATTERAS…AS HI BRIDGES OUT OFF DELMARVA GRADIENT TO TIGHTEN S OF HATTERAS LATER TONIGHT. CURRENTLY WINDS HAVE BEGUN TO NOSE UP A BIT AS SHIFT TO N THEN NE…WILL CONT WITH CURRENT WORDING AND BRING WINDS UP TO 15 TO 25 KT WITH A SPLIT OF CAPE ROMAIN FOR SEAS THROUGH FRI WITH 7 TO 10 FT.

EXTENDED…NO BIG DIFFERENCE WITH EXITING TROF 60 TO 66 HRS. TREND HAS BEEN WEAKER AS TROF LOSES AMP. AVN HAS SETTLED INTO A FRAGMENTED DVLPMNT TO LIFT NE FM OFF SE COAST FRI NIGHT INTO SAT. CANADIAN REMAINS STRONGER WITH LEAD IMPULSE AND WITH SECONDARY TRAILG LOW. AM NOT CONVINCED THIS THE CASE. ECMWF IS FASTER AND WEAKER…EARLIER UKMET IS ALSO FRAGMENTED. WILL CONSIDER BACKING OFF ON CURRENT WORDING FOR PSBL GALES S/E 1000 FMS AND MODERATE WINDS NEW ENGLAND WATERS.

WARNINGS…NT1 NEW ENGLD WTRS…GALE…GULF OF MAINE AND GEORGES BANK FOR EARLY MORNING…S OF NEW ENGLAND REMAINDER OF NIGHT. NT2 MID ATLC WTRS…GALE…NTHRN PORTION OF S/E OF 1000 FMS.

FORECASTER SIENKIEWICZ. MARINE FORECAST BRANCH