AMPS Information

AMPS Forecast Products

The following are descriptions of the plots and fields available through the AMPS web page display.

SFC: Temperature (C) and winds (kt) at lowest model half-eta level (approx. 14 m AGL for the AMPS configuration).
Full barb= 10 kt; half barb= 5 kt. For legibility, wind barbs are not plotted at every model grid point.

Sfc RH: Relative humidity w.r.t. ice, temperature (C), and winds (kt) at lowest model half-eta level (~14 m AGL).
Full barb= 10 kt; half barb= 5 kt. For legibility, wind barbs are not plotted at every model grid point.

Sfc RH (H2O): Relative humidity w.r.t. liquid water, temperature (C), and winds (kt) at lowest model half-eta level (~14 m AGL).
Full barb= 10 kt; half barb= 5 kt. For legibility, wind barbs are not plotted at every model grid point.

Precip: Total precipitation amount (mm) for listed period ending at the plot verification time.
60-, 20-km grids= past 3 hrs; 6.7-, 2.2-km grids= past 1 hr. Total precipitation is the sum of precip produced by both the WRF's explicit scheme and the cumulus parameterization. (The Cu param is run on all grids except 2.2-km.)

Cloud base: shows cloud ceiling (in feet) with color shading, horizontal wind barbs at the lowest model half-eta level (~14 m AGL), and relative humidity contours (w.r.t. ice) at approximately 3,000 feet AGL.

Sea ice: Sea ice fraction.
Red line is 271.4K ground/water temperature isotherm.

Upper air: Plots of winds, heights, RH, PV, cloud, vorticity, and other fields at various levels. Not all plots described below are available for all model grids or windows.

"1k RH" and "3k RH" show RH w.r.t. ice and winds at 1000 ft and 3000 ft AGL, respectively.

"925", "850", "700", and "600" show geopotential height (m), temperature (C), RH w.r.t. ice, and winds at the 925 hPa, 850 hPa, 700 hPa, or 600 hPa levels.

"500" shows geopotential height (m) and total (integrated) cloud water and cloud ice mixing ratio (g/kg) at 500 hPa.

"500 vor" shows geopotential height (m) and relative vorticity (x10-5s-1) at 500 hPa.

"300" shows potential vorticity (PVU), wind isotachs (m/s), and wind barbs (full barb= 10 kt; half barb= 5 kt) at 300 hPa.

"850 wetbulb T" shows wetbulb temperature at 850 hPa and contours of sea-level pressure

"850 wetbulb pot. T" shows wetbulb potential temperature at 850 hPa and contours of sea-level pressure

"1k AGL flight lvl", "3k AGL flight lvl", "5k AGL flight lvl", "10k AGL flight lvl" and "15k AGL flight lvl" show wind barbs, color shaded wind speeds, and contoured temperatures at the 1,000 ft, 3,000 ft, 5,000 ft, 10,000 ft and 15,000 ft AGL flight levels.

"25k MSL flight lvl" and "30k MSL flight lvl" show wind barbs, color shaded wind speeds, and contoured temperatures at the 25,000 ft and 30,000 ft MSL flight levels.

"altimeter" shows color-shaded altimeter setting, in inches of mercury.

Soundings: Skew-T plots and profiles of temperature (C) and dewpoint (C) vs. pressure for the locations indicated.

Tables: Textual time series. See description below under "Textual Time Series".

Cross sections: Vertical cross sections along traces shown under "x-sec locations" selection.
At bottom of cross-section, the direction of the ends of the view (e.g., S= south, N= north) are marked.
Some cross-sections listed by endpoints: e.g., MCM-VOSTOK= McMurdo-Vostok.

"RH" shows relative humidity w.r.t. ice, potential temperature (K), and wind vectors in the plane of the cross-section.

"Cloud X-sec" shows temperature (C) and snow, rain, cloud water, and cloud ice mixing ratios (g/kg).

PseudoSat: shows column-integrated cloud water and column-integrated hydrometeor fields, shaded to simulate what might be seen in IR satellite imagery.

Sfc wind: Wind barbs and wind speed (m/s) at lowest model half-eta level (~14 m AGL) on the 6.7-km and 2.2-km domains.
Full barb= 10 kt; half barb= 5 kt.
On the 2.2-km Ross Is. window, the winds are plotted at every grid point.

Meteograms : Time-height sections and time series at the specified location.


Animations

Selecting the "Animations" button opens a separate animation window. Any of the fields listed in the animation window can be displayed. The forecast initial time and model grid/window to be displayed are selected in the chooser (middle) frame of the web page.


Plot information

Date/forecast hour group: The model initialization time and forecast hour are shown at the top of product plot.
E.g., "00 UTC 1 Jan 2050 + 30.0" = Hour-30 forecast from the 0000 UTC 1 Jan 2050 initialization.
The forecast product valid time is determined by adding the forecast hour to the initialization time.

Field listing: The fields printed at the top of the plot are those depicted. The list above explains these.


Textual Time Series

Textual tables are styled after FOUS bulletins. Tables from the 60-km and 20-km AMPS domains show data every 3 hours, while tables from the 6.7-km and 2.2-km domains show data every hour. The columns of the tables contain the following information:

Example:

NZCM Williams Field     (lat, lon) = (-77.87, 166.98) 
Forecast initialized at 2008101612 
AMPS 20km domain 
 

FCST  UTC     T     Td   Altim  Spd  Dir Grid   VVV   RH1RH2RH3     T1T2T3 ACCUM
 HR   HR     (C)   (C)  (in Hg)(kts)(deg)(deg)  (*)  (% wrt water)    (C)   (*)

 00   12  -27.7  -32.2   28.90    7  172  339  -000   081041079  M26M21M21  000                     
 03   15  -21.4  -24.8   28.92    9   49  216   020   075071071  M21M21M21  000                     
 06   18  -18.0  -22.9   28.90   12   37  204  -007   066064073  M19M20M21  000                     
 09   21  -17.6  -24.0   28.86    6   35  202  -005   059054064  M18M19M20  020                     

The data in the last line are valid at 21 UTC on 16 October 2008, 9 hours after the model initialization. The forecast surface temperature at that time is -17.6 C, the surface dewpoint temperature is -24.0 C, and the altimeter setting is 28.86 inches Hg. The wind speed is 6 knots and the geographic wind direction is 35 degrees (202 degrees with respect to grid north). The vertical motion at 700 hPa is downward at a rate of 0.5 microbar/s. Relative humidity at the surface is 59%, 54% at 1000 feet AGL, and 64% at 3000 feet AGL with respect to liquid water. The temperature is -18 C at 500 feet AGL, -19 C at 1000 feet AGL, and -20 C at 1500 feet AGL. The liquid equivalent of 0.20 mm of precipitation have accumulated over the past 3 hours (since forecast hour 6, in this example).


Header Links

Some useful links are included at the top of the model display. They include: