Check the SHEF manual for details about how SHEF format works

Our SHEF files (there are 5 of them) are split up by basin, with each file
containing individual SHEF messages (one message for each location) for that
basin. We have three data types:

HMIFW: Surge-only
HMIFX: Surge + Tide
HMIFV: Surge + Tide + Anomaly

The file sorc/combAll.fd/makeSHEF.f controls what goes in the SHEF messages.
sorc/combAll.fd/combineAll.f sets up WMO headers and AWIPS IDs for SHEF messages.

Our WMO Headers are:
SRUS70 KWNO - Conus
SRAK70 KWNO - Alaska

Our AWIPS IDs are:
TIDTWE - East Coast
TIDTWG - Gulf of Mexico
TIDTWP - West Coast
TIDTWC - Gulf of Alaska
TIDTWB - Bering and Arctic Sea Alaska

Example Header
SRAK70 KWNO TIDTWA 251200

"SRAK70 KWNO" - WMO Header
"TIDTWA" - AWIPS ID
"251200" - DDHHMM of forecast

Example SHEF:
.E RDDA2 20150625 Z DC201506251637/DH1200/HMIFV/DIH01 
.E1     0.416/   1.087/   1.110/   1.507/   1.419/   1.259/   1.158/   1.018/   0.865/   0.725/   0.618/   0.456
.E2     0.256/   0.330/   0.423/   0.505/   0.553/   0.564/   0.538/   0.484/   0.416/   0.360/   0.332/   0.334
.E3     0.366/   0.427/   0.508/   0.586/   0.640/   0.661/   0.644/   0.586/   0.494/   0.390/   0.303/   0.249
.E4     0.238/   0.272/   0.343/   0.429/   0.505/   0.453/   0.469/   0.454/   0.410/   0.251/   0.199/   0.170
.E5     0.169/   0.196/   0.252/   0.327/   0.400/   0.452/   0.471/   0.453/   0.391/   0.295/   0.189/   0.104
.E6     0.053/   0.044/   0.079/   0.152/   0.238/   0.315/   0.368/   0.392/   0.384/   0.342/   0.282/   0.227
.E7     0.192/   0.184/   0.207/   0.264/   0.343/   0.520/   0.575/   0.595/   0.671/   0.601/   0.496/   0.485
.E8     0.399/   0.449/   0.444/   0.586/   0.765/   0.958/   1.041/   1.199/   1.226/   1.215/   1.168/   1.100

"E" stands for time series data

"RDDA2" is the National Weather Service Location Identifier (NWSLI) which gives the 
station location for this SHEF message. Stations MUST have these to be included in
the SHEF output

"20150625" is the forecast date

"Z" indicates UTC time

"DC201506251637" is the creation time of the actual message

"DH1200" means forecast time starting at 12Z

"HMIFV" is the data type (surge+tide+anom in this case)

"DIH01" means data are given in increments of one hour from the forecast time

Any "M" indicates missing data