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MOS Changes


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DATE CYCLE CHANGES NWS Notifications
April 8, 2014
1200 UTC
MDL adds Predominant Weather, Precipitation Type, and Probability of Precipitation Occurrence to 2.5 km Gridded GFS-MOS product suite for the 0000 UTC and 1200 UTC cycles. GRIB2 files are disseminated across the Satellite Broadcast Network (SBN) and sent to experimental National Digital Guidance Database (NDGD) on the NWS ftp server. WMO Headings Docs: CONUS | Alaska TIN 13-49
November 5, 2013
1200 UTC
MDL begins producing GFS MOS extended-range mean total sky cover for the 1200 UTC cycle and updates 0000 UTC mean total sky cover. More details TIN 13-20
November 5, 2013
1200 UTC
MDL begins producing GFS MOS total sky cover and ceiling guidance for 15 stations in the western Pacific Ocean. TPB TIN 13-22
November 5, 2013
1200 UTC
MDL implements new GFS MOS wind speed/direction equations for the cool season. TIN 13-30
December 5, 2012
1200 UTC
MDL begins dissemination of experimental 2.5 km Gridded MOS across the Satellite Broadcast Network (SBN) and NOAAPORT. The experimental NWS FTP server continues to be populated with GRIB2 data, but they will now contain WMO headers. WMO Headings Doc TIN 12-09
Sept 5, 2012
1200 UTC
EMC implements fix to the GFS Land Surface Model to improve cool and moist bias in the near surface air temprature and moisture fields during the warm season. TIN 12-42
June 12, 2012
1200 UTC
MDL implements new GFS MOS wind speed/direction equations for the warm season. TIN 12-25
May 22, 2012
1200 UTC
EMC upgrades GFS data assimilation to a hybrid variational/ensemble-KF (Kalman Filter) system. More details can be found on the EMC Model Changes Page N/A
March 13, 2012
1200 UTC
MDL replaces traditional Gridded MOS POP/QPF (2.5-km CONUS) with High Resolution MOS POP/QPF guidance. TIN 12-12
February 27, 2012
1200 UTC
MDL begins producing Gridded MOS for CONUS on the 2.5 km NDGD grid. PNS
May 9, 2011
1200 UTC
EMC implements changes to the GFS Global Data Assimilation System (GDAS) as well as various GFS model changes ("bugfix"). For full details, please see the EMC Model Changes Page N/A
November 9, 2010
1200 UTC
MDL begins producing Gridded MOS for Hawaii on the 2.5 km NDGD grid. TIN 10-27
August 3, 2010
1200 UTC
MDL will change the sky cover guidance in the GFS MOS BUFR products from total sky cover to opaque sky cover. Additionally, precipitation type and snowfall guidance will be added to the extended-range GFS MOS BUFR product, and many other elements will be extended out to 264 h. MOS BUFR documentation. TIN 10-20
March 30, 2010
1200 UTC
MDL makes the following modifications to the CONUS GFS-based gridded MOS guidance:
  1. Addition of extended-range (out to 156-h) 24-hr Snowfall Amount for the 1200 UTC cycle.
  2. Addition of two (2) forecast projections for 24-hr Snowfall amount (out to 156-h) for the 0000 UTC cycle.
  3. Modify the CONUS output mask for all elements except 24-hr Snowfall Amount.
Additionally, MDL will now produce 24-hr Snowfall Amount guidance (out to 156-h) for 0000 and 1200 UTC cycles for Alaska GFS-based gridded MOS.
TIN 10-04
March 3, 2010
1200 UTC
MDL adds 289 sites to and removes 29 from the GFS MOS BUFR and text products. Additionally, MDL implements new equations for maximum/minimum temperature, 2-m temperature and dewpoint, wind speed/direction, wind gusts, probability of thunderstorms, ceiling height, 24-h snowfall, and conditional precipitation type. Station information TIN 09-39
January 12, 2010
1200 UTC
MDL begins producing GFS-based gridded MOS 6- and 12-hr QPF and 24-hr Snowfall Amount guidance for Alaska. TIN 10-04
March 3, 2009
1200 UTC
MDL removes the NGM MOS guidance and all associated products. This includes the NGM-based trajectory model as well. This removal coincides with the removal of the NGM model and all associated products. A list of MDL's NGM-based products is available along with suggested replacement products. TIN 08-90
December 16, 2008
1200 UTC
MDL begins producing GFS-based gridded MOS 6- and 12-hr POP, wind speed, direction and gusts, and sky cover guidance for Alaska. TIN 08-69
December 9, 2008
1200 UTC
MDL replaces the Eta MOS with a new NAM-based MOS package. TIN 08-89
September 16, 2008
1200 UTC
MDL adds temperature and dewpoint temperature to the Pacific MOS guidance. TIN 08-55
August 12, 2008
1200 UTC
MDL stops the cycle-averaging of station data in the GFS-based CONUS gridded MOS wind forecasts. More details N/A
June 10, 2008
1200 UTC
MDL begins producing Gridded MOS guidance for Alaska on the 3 km NDFD grid. TIN 07-82
May 1, 2008
0000 UTC
MDL begins producing GFS-based thunderstorm and severe weather MOS guidance for Alaska and including it in the MAV/MEX text products and GFS BUFR products. TIN 08-10
Dec 18, 2007
1200 UTC
MDL makes modifications to the CONUS gridded MOS guidance -- 1) new land/water mask, 2) new QPF analysis scheme, and 3) removal of problem stations from analysis. More details N/A
Sept 11, 2007
1200 UTC
MDL updates max/min climate normals for the CONUS stations in the MEX text product and increases the number of stations in the GFS-based visibility, obstruction to vision and probability of precipitation occurrance guidance. TIN 07-42
June 5, 2007
1200 UTC
MDL replaces Total Sky Cover guidance in short-range GFS MAV MOS with new Opaque Sky Cover guidance. Verification TIN 07-34
June 5, 2007
1200 UTC
MDL adds opaque sky cover, wind gusts, 24-h snowfall, and 6-h and 12-h Quantitative Precipitation Forecasts (QPF) to the Gridded MOS system. Also, MDL upgrades processing of previously existing elements, and expands forecast guidance coverage. TIN 06-87
April 24, 2007
1200 UTC
MDL adds Probability of Precip (POP) and Probability of Precip Occurrance (POPO) to the GFS MOS guidance for the 15 island locations in the Western Pacific Ocean. TIN 07-07
August 15, 2006
1200 UTC
MDL begins producing Gridded MOS guidance on the 5km NDFD grid. More details TIN 05-56
August 15, 2006
1200 UTC
MDL removes obsolete short-range GFS BUFR products. TIN 06-48
August 15, 2006
1200 UTC
MDL adds 88 stations to the GFS MOS BUFR and text products. New station list TIN 06-32
TIN 06-33
July 11, 2006
1200 UTC
MDL modifies GFS-based extended-range wind guidance and adds WND to 12Z MEX text product. TIN 06-21
June 20, 2006
1200 UTC
The NWS will run an interim 32-km Eta model for the 0000 and 1200 UTC forecast cycles. Model output from this Eta run will be used as input to the Eta MOS. Direct Eta model output will no longer be available on NWS servers. TIN 06-40
June 20, 2006
1200 UTC
MDL implements new maximum/minimum temperature, 2-m temperature, dew point, wind, and wind gust equations to generate guidance for all cycles of the GFS-based short- and extended-range MOS guidance. This should reduce the differences between the accuracy and character of the 00Z and 12Z MOS guidance. In addition, about 90 new stations were added to the equations. These new stations will be available in August 2006 - See Above. N/A
June 20, 2006
1200 UTC
MDL adds GFS-based maximum/minimum temperature guidance text product for Alaskan RFC. TIN 06-16
June 20, 2006
1200 UTC
MDL changes the inflation technique applied to the wind speed forecasts in the GFS- and Eta-based MOS guidance. We will no longer inflate wind speed forecasts, when the forecasts are below the mean wind speed. The result will be fewer forecasts of calm winds. Wind speeds forecast above the mean wind speed will still be inflated. More details N/A
May 30, 2006
1200 UTC
MDL modifies experimental ensemble messages to respond to NCEP's global ensemble upgrade. N/A
Apr 25, 2006
1200 UTC
MDL's probability of thunderstorm guidance now based on a 40km grid instead of the original 47km grid. Thunderstorm guidance now available out to 192 hours in 1200 UTC MEX text product. TIN 06-17
Nov 1, 2005
1200 UTC
MDL adds visibility and obstruction to vision guidance to the Eta MOS. TIN 05-43
Nov 1, 2005
1200 UTC
MDL changes the station identifier for Kalispell, MT from KFCA to KGPI in our GFS and Eta-based text products. The NGM-based text product will change from FCA to GPI. TIN 05-59
Oct 11, 2005
1200 UTC
MDL begins producing new extended-range GFS-based MOS BUFR products at 0000 and 1200 UTC. TIN 05-49
Sept 27, 2005
1200 UTC
MDL removes obsolete NGM-MOS-based Redbook graphics. TIN 05-52
Sept 27, 2005
1200 UTC
MDL adds extended-range GFS-based text product for US and Canadian sites for the 1200 UTC model run. TIN 05-42
June 7, 2005
1200 UTC
MDL adds wind speed and direction guidance for 13 island locations in the Western Pacific Ocean to the GFS-based short-range MOS at 0000 and 1200 UTC. TIN 05-08
April 19, 2005
1200 UTC
MDL adds wind speed and direction guidance for 2 Pacific Ocean sites to the GFS-based short-range MOS at 0000 and 1200 UTC. TIN 05-07
February 8, 2005
1200 UTC
MDL modifies GFS-based short-range MOS guidance BUFR products. More details N/A
February 8, 2005
1200 UTC
MDL begins disseminating Eta-based MOS guidance in BUFR format. More details N/A
February 8, 2005
1200 UTC
MDL begins Eta-based MOS temperature and wind guidance for marine sites. More details N/A
February 8, 2005
1200 UTC
MDL sends GFS-based max/min MOS guidance for cooperative observer sites on the SBN. 1200 UTC cycle extended-range message added. More details. N/A
January 11, 2005
1200 UTC
All NGM-based trajectory products removed except for Redbook graphics of net vertical displacements and trajectories. TIN 04-59
November 18, 2004
1200 UTC
Graphical depictions of the GFS- and Eta-based snowfall forecasts are added to our webpages. More details. N/A
September 21, 2004
1200 UTC
Air temperature and dew point temperature added to the GFS MOS marine text products. More details. N/A
September 21, 2004
1200 UTC
Change to Dennison, TX station identifier in short- and extended-range GFS MOS text products. TIN 04-29
September 21, 2004
1200 UTC
Several modifications made to GFS-based RFC MOS max/min temperature text product format and station content. TIN 04-28
September 21, 2004
1200 UTC
NGM MOS BUFR messages no longer segmented internally. TIN 04-31
May 26, 2004
0000 UTC
Extended-range GFS MOS guidance production time moved from 0700 UTC to 0500 UTC. TIN 04-11
May 25, 2004
1200 UTC
MDL officially started producing short- and extended-range GFS-based COOP MOS max/min temperature text products. Test guidance had been available since December 2003. Products also made available on NWS FTP server. More details N/A
May 18, 2004
1200 UTC
GFS short-range MAV MOS visibility, ceiling height, and sky cover definitions changed. TIN 04-09
April 20, 2004
1200 UTC
MDL adds 66-hr and 72-hr forecasts added to Eta MET text message. N/A
February 24, 2004
1200 UTC
Changes are being made to the Eta MOS content, including the format of the bulletin and the stations available. Snowfall amount and ceiling height guidance are being added. All the details of the February 2004 Eta changes are outlined here N/A
February 17, 2004
1200 UTC
The Eta MOS forecast equations have been updated. As a result, the guidance delivery time will be delayed by approximately 30 minutes. In addition, some of the sites in the messages have been modified. All the details are outlined here N/A
December 19, 2003
1200 UTC
MDL begins producing test forecasts of GFS MOS maximum/minimum temperature guidance based on data from cooperative observer network data. At this time the guidance is available only on our webpage. All the details are outlined here N/A
December 16, 2003
1200 UTC
MDL makes several significant changes to the GFS MOS, including new stations, new equations, new snowfall amount forecasts, and unifying the AVN and MRF MOS into the GFS MOS system. All the details are outlined here N/A
May 6, 2003
1200 UTC
MDL began producing new Marine MOS wind guidance based on the GFS model. more details N/A
April 8, 2003
0000 UTC
The obsolete MRF MOS products (AWIPS category FMR) were removed from production. The alphanumeric, grib, and graphics products are no longer available. These products have been replaced with the improved MRF MOS (AWIPS category MEX) guidance. N/A
October 1, 2002
0000 UTC
Improved AVN POP and QPF guidance for Hawaii will be implemented on October 1, 2002. more details N/A
September 18, 2002
0000 UTC
New medium range wind guidance is being added to the MRF MOS messages. more details N/A
September 17, 2002
1200 UTC
Visibility and obstruction to vision will be added to the 0600/1800 UTC AVN MOS guidance, and the probability of precipitation occurrence (PoPO) will be added for all four cycles of the AVN-based MOS guidance. more details N/A
September 17, 2002
1200 UTC
Eta-based MOS guidance is being updated to include new thunderstorm and severe weather guidance. more details N/A
September 16, 2002
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Changed Text Message by Station List web page forms posting method from POST to GET to allow automated retrieval and easier bookmarking.more details N/A
August 21, 2002
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All MDL data available via ftp will be moved from tgsv1.nws.noaa.gov to tgftp.nws.noaa.gov. more details N/A
July 30, 2002 1200 UTC MDL adds climatological values of max/min temperature and PoP for some sites to the MRF MEX MOS message.more details N/A
July 25, 2002 1200 UTC NCEP has scheduled their quarterly test of their back-up systems. Some 1200 UTC products may be disseminated late or not at all. N/A
June 11, 2002 1200 UTC MDL starts disseminating new MOS guidance based on the Eta model. more details N/A
May 21, 2002 1800 UTC A correction is made to the 12-h PoP and QPF forecasts for the Hawaiian sites in the 0600 and 1800 UTC AVN MAV alphanumeric messages. N/A
May 14, 2002 1200 UTC Updated FOUS12 guidance is produced for the remaining four RFCs. Day 11 minimum temperatures added to all 9 RFC messages. N/A
April 30, 2002 0000 UTC The obsolete AVN MOS products (AWIPS category FAN) will be removed from production. The alphanumeric, grib, and graphics products will no longer be available after April 30, 2002. These products have been replaced with the improved AVN MOS (AWIPS category MAV) guidance. N/A
April 24, 2002 0000 UTC On March 6, 2002, NCEP changed the configuration of the Global Forecast System (GFS) to provide four runs of the Global Spectral Model for forecast projections out to 384 hours. Since the changes made on March 6 provide four extended runs of the GFS, NCEP is terminating the MRF, effective April 24, 2002. The impact of these changes on the current suite of AVN and MRF MOS guidance is minimal. More Details N/A
April 18, 2002 1800 UTC MDL has begun producing QPF guidance as part of the 0600 and 1800 UTC AVN MAV MOS package. N/A
April 4, 2002 0000 UTC NCEP has scheduled a test of their back-up systems. Therefore 0000 UTC NGM and AVN MOS are expected to be disseminated approximately 6 hours late. N/A
April 2, 2002 1400 UTC MDL's webpages will be moved to the NWS's upgraded web server. more details N/A
April 2, 2002 1200 UTC MDL will begin producing MOS guidance for max/min temperature, surface temperature, dewpoint, and cloud cover as part of the experimental Eta MOS package. more details N/A
April 2, 2002 1200 UTC MDL will begin putting graphical images of the AVN MAV, MRF MEX and experimental ETA MOS forecasts on the webpage. more details N/A
March 21, 2002 1200 UTC MDL begins putting experimental Eta MOS text messages on the webpage. more details N/A
January 22, 2002 1200 UTC MDL adds 323 new sites to the new AVN and MRF MOS guidance. more details N/A
December 11, 2001 1200 UTC FOUS12 max/min guidance for the North Central RFC has been converted from the old NGM/MRF MOS to the new AVN/MRF MOS. more details N/A
November 27, 2001 1800 UTC Maximum/minimum temperature, surface temperature, dew point, probability of thunderstorms, and conditional probability of severe thunderstorm guidance added to the 0600/1800 UTC AVN MOS. more details N/A
November 27, 2001 1200 UTC Updated equations for maximum/minimum temperature, surface temperature, and dew point are implemented for the 0000/1200 UTC AVN MOS guidance. N/A
October 30, 2001 1800 UTC Probability of Precipitation (PoP) will be added to the 0600/1800 UTC AVN MOS guidance. More details about recent and upcoming changes N/A
October 16, 2001 1800 UTC MDL began producing new 0600/1800 UTC AVN MOS guidance packages for the same sites and in the same format as the current 0000/1200 UTC packages, but not all elements are currently available. Please note that the same product identifiers are used as with the 0000/1200 UTC packages. more details N/A
October 10, 2001 1200 UTC The 1200 UTC AVN MOS guidance will NOT be available on Wednesday, October 10th, 2001 due to the NCEP site outage backup test. more details N/A
September 25, 2001 1200 UTC MDL has begun producing new Air Force alphanumeric bulletins. These products do not contain any new guidance, but are a repackaging of existing MEX or MAV messages for a subset of stations. more details N/A
July 24, 2001 1200 UTC MDL has begun producing guidance for categorical forecasts of precipitation amount (QPF) in the AVN MOS alphanumeric messages. In addition, the equations used to produce the visibility and obstruction to vision guidance have been updated. more details N/A
June 25, 2001 1200 UTC MDL has begun producing test AVN MAV alphanumeric messages containing QPF guidance. more details N/A
June 19, 2001 1200 UTC The 1200 UTC AVN MOS guidance will NOT be available on Tuesday, June 19th, 2001 due to the NCEP site outage backup test. more details N/A
May 15, 2001 1200 UTC NCEP's changes to the physics package of the Global Spectral Model expected to impact the new AVN and MRF MOS. more details N/A
May 9, 2001 0000 UTC 12- and 24-h Probability of Thunderstorms added to the MRF MOS guidance. more details N/A
May 2, 2001 1200 UTC Updated FOUS12 max/min temp guidance for RFCs is produced and disseminated. more details N/A
April 3, 2001 1200 UTC BUFR messages containing new AVN(MAV) and MRF(MEX) MOS forecasts are produced and disseminated. more details N/A
April 1, 2001 0000 UTC Warm season AVN MAV/MRF MEX forecast equations take effect. more details N/A
March 16, 2001 0000 UTC Spring AVN MAV thunderstorm and severe weather equations take effect. N/A
February 27, 2001 0000 UTC Experimental MOS guidance based on output from the 0000 UTC Ensemble runs of the MRF made available. more details N/A
February 12, 2001 1200 UTC Enhancements made to AVN Visibility, Obstruction to Vision, and Conditional Probability of Severe Thunderstorm guidance. more details N/A
October 10, 2000 1200 UTC Visibility and Obstruction to Vision guidance added to AVN MOS. N/A
October 8, 2000 ---- NWS Headquarters restructure effective. TDL becomes the Meteorological Development Laboratory (MDL). The Synoptic Scale Techniques Branch (SSTB) becomes the Statistical Modeling Branch. N/A
October 4, 2000 0000 UTC Precipitation Type and Mean Total Sky Cover added to the MRF MOS. N/A
September 20, 2000 1200 UTC Severe Weather and Probability of Precipitation (PoP) added to AVN MOS. more details N/A
July 19, 2000 0000 UTC Probability of Precipitation (PoP) and Quantitative Precipitation Forecasting (QPF) added to MRF MOS. more details N/A
July 18, 2000 1200 UTC Precipitation Type and Total Sky Cover added to AVN MOS. more details N/A
May 31, 2000 0000 UTC New MRF MOS issued including Maximum/Minimum Temperature, Temperature, and Dewpoint. more details (includes AWIPS ID and WMO Headers) N/A
May 30, 2000 1200 UTC New AVN MOS issued including Maximum/Minimum Temperature, Temperature, Dewpoint, and Winds. more details (includes AWIPS ID and WMO Headers) N/A
August 1999 ---- Synoptic Scale Techniques Branch (SSTB) of TDL enhances webpage at "www.nws.noaa.gov/mdl/synop". N/A

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Office Of Science and Technology
Meteorological Development Laboratory
Statistical Modeling Branch
1325 East West Highway
Silver Spring, MD 20910
Page Author: MOS Web Team
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Page last Modified: Tuesday, 08 April 2014 16:36 UTC