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| DECODING FOUS DATA |
What is FOUS Data? FOUS data is point specific numerical model data. It is code that gives a station's expected precipitation, relative humidity, synoptic lift, instability, surface wind, standard 1000-500 mb thickness and low level temperature profile from the current time period to later time periods given in time increments.
Where can I get FOUS Data? There are some web sites that offer FOUS. Private vendors also offer this data for weather graphics stations. Here are some web sites that offer the raw FOUS Data:
http://asp1.sbs.ohio-state.edu/ (click models, then scroll down to bottom)
http://www.met.tamu.edu/personnel/students/weather/weather_interface.html (input 3 letter station ID, pick "model data" radio button and within menu choose "all model output")
How is the FOUS decoded?
Format of data:
FOXXII KWBC DDTTTT
TTPTTR1R2R3 VVVLI PSDDFF HHT1T3T5
----------------------------------
NNN//R1R2R3 VVVLI PSDDFF HHT1T3T5
06PTTR1R2R3 VVVLI PSDDFF HHT1T3T5
12PTTR1R2R3 VVVLI PSDDFF HHT1T3T5
18PTTR1R2R3 VVVLI PSDDFF HHT1T3T5
24PTTR1R2R3 VVVLI PSDDFF HHT1T3T5
30PTTR1R2R3 VVVLI PSDDFF HHT1T3T5
36PTTR1R2R3 VVVLI PSDDFF HHT1T3T5
42PTTR1R2R3 VVVLI PSDDFF HHT1T3T5
48PTTR1R2R3 VVVLI PSDDFF HHT1T3T4
CODE EXPLANATION
===== ================
06, etc Forecast valid time. (Add this number to forecast run time).
XX Region identifier.
II Station group number.
DD Day of the month forecast was issued.
TTTT Greenwich time of forecast cycle on which the data is based. Click here for an explanation on converting local time to Z time.
NNN Forecast station three letter identifier.
PTT 6 hour accumulated precipitation during previous 6 hours in hundredths of inches.
R1 Mean relative humidity of the lowest model layer (lowest 35 mb), in percent.
R2 Mean relative humidity of model layers 2 through 9 (up to 500 mb), in percent.
R3 Mean relative humidity of model layers 10 through 13 (500 to 200mb), in percent.
VVV Vertical velocity at 700mb, in tenths of a microbar per second, weighted average of three hourly values at forecast time, one hour before, and one hour after (double weighted at forecast time). Minus sign represents downward motion. Click here and here for explanations on interpreting UVV
LI Lifted index in degrees Celsius. Negative values are designated by subtracting from 100;
e.g. -4= 96. Taken from the lowest (most unstable) of four possible values. The values derived from lifting parcels from the four lowest model layers up to 500 mb. Click here for an explanation on interpreting LI
PS Sea level pressure calculated from lowest sigma level (based on the contour base map). The preceding 10 or 9 is left off. Pick value that is closest to average surface sea level pressure of 1013 mb. i.e. 30 = 1030 mb (930 mb is unrealistically too low unless a hurricane is overhead). 80 = 980 mb (1080 is unrealistically too high unless extreme arctic high pressure is overhead.)
DD Direction in tens of degrees of the mean wind in the lowest model layer (35 mb).
FF Wind speed in knots of the lowest model layer (lowest 35 mb).
HH 1000-500 mb thickness in decameters with the first digit omitted. The first digit is a 5 in most cases since average sfc to 500 mb thickness is near 5,500 gpm. i.e. 40 = 540 dm = 5,400 gpm. Click here for an explanation on interpreting thickness
T1 Temperature in model layer 1 (lowest 35 mb) in degrees Celsius. If temperature is below freezing, it is coded as the difference from 100. i.e. 97 = -3 C, 88 = -12 C
T3 Temperature in model layer 3 (approximately 900 mb).
T5 Temperature in model layer 5 (approximately 800 mb).
Here is an example of FOUS and the decoding:
361
FOUS69 KWNO 161200
OUTPUT FROM ETA 12Z DEC 16 01
TTPTTR1R2R3 VVVLI PSDDFF HHT1T3T5 DFW//969272 03902 121110 65151409 06089979167 06500 121803 64161408 12020936119 -0602 113411 60151207 18000925106 -3605 183119 50110704 24000906705 -4806 193116 47090600 30000622206 -4114 223213 52100603 36000501320 -2316 193009 59120806 42000521523 -0415 202808 61101008 48000551922 -0216 182706 61081008 54000592036 00115 192203 62111108 60000552147 -0113 151606 62141208
Decoding:
DFW= 3 letter identifier
TT= Z time (goes in 6 hour increments). Values are given on far left
PTT= 6 hour precip in 100ths of inches
R1R2R3= RH values
06089979167= 6 hours after initial, 0.89" of precip during previous 6 hours, 97% RH is lowest 35 mb, 91% RH from sfc to 500 mb, 67% RH from 500 to 200 mb
12020936119= 12 hours after initial, 0.20" of precip during previous 6 hours, 93% RH is lowest 35 mb, 61% RH from sfc to 500 mb, 19% RH from 500 to 200 mb
VVV= upward vertical velocity is 10ths of microbars per second (ub/s)
LI= lifted index
06500 = UVV= 6.5 ub/s (moderate synoptic lift), LI= 0 (low instability)
-0602 = UVV= -0.6 ub/s (slight sinking), LI= 2 (stable instability)
PS= sea level pressure
DD= low level wind
FF= wind speed
121803= 1012 mb sea level pressure, 180 deg low level wind (south wind), 3 knot low level wind
113411= 1011 mb sea level pressure, 340 deg low level wind (north-northwest wind), 11 knot low level wind
HHT1T3T5= low level temperature and thickness profile
64161408= 5640 meter thickness (in coding first digit is left off and 0 at end is left off), 16 C low level temperature, 14 C near 900 mb, 8 C near 800 mb
For another source of decoding, go to website below:
http://weather.cod.edu/notes/output.html