Changes To The GFS Effective 7/28/2010! Another Upgrade.

[srainhoutx]

Hopefully the tweaking of the model will provide for some better guidance.

TECHNICAL IMPLEMENTATION NOTICE 10-15
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
853 AM EDT FRI APR 2 2010

TO: SUBSCRIBERS:
-FAMILY OF SERVICES
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
-NOAAPORT
OTHER NWS PARTNERS...USERS AND EMPLOYEES

FROM: TIMOTHY MCCLUNG
SCIENCE PLANS BRANCH CHIEF
OFFICE OF SCIENCE AND TECHNOLOGY

SUBJECT: GLOBAL FORECAST SYSTEM CHANGES:
EFFECTIVE JUNE 22 2010.

EFFECTIVE JUNE 22 2010...BEGINNING WITH THE 1200 COORDINATED
UNIVERSAL TIME /UTC/ RUN...THE NATIONAL CENTERS FOR
ENVIRONMENTAL PREDICTION /NCEP/ WILL UPGRADE THE GLOBAL
FORECAST SYSTEM /GFS/. THE RESOLUTION OF THE GLOBAL FORECAST
MODEL WILL BE INCREASED FROM T382 /35 KM/ TO T574 /27 KM/.
THE HIGH RESOLUTION PORTION OF THE FORECAST WILL BE EXTENDED
FROM 180 HRS TO 192 HRS. WITH THIS EXTENSION 3 HOURLY OUTPUT
WILL BE MADE AVAILABLE OUT TO 192 HOURS.

THIS WILL RESULT IN SIGNIFICANT CHANGES IN THE DEFINITION OF
PARAMETERS IN THE 192 HOUR PRESSURE GRIB /PGRB/ AND FLUX
FILES. THERE WILL ALSO BE SIGNIFICANT CHANGES IN MODEL
PHYSICS ASSOCIATED WITH THIS CHANGE. IN ADDITION
MODIFICATIONS WILL BE MADE TO THE CONTENTS OF THE GLOBAL DATA
ASSIMILATION SYSTEM /GDAS/ AND GFS PGRB FILES.

CHANGES IN MODEL PHYSICS INCLUDE:

RADIATION AND CLOUD OVERLAP
GRAVITY WAVE DRAG
HURRICANE RELOCATION
NEW PLANETARY BOUNDARY LAYER SCHEME
NEW MASS FLUX SHALLOW CONVECTION
UPDATED DEEP CONVECTION SCHEME
POSITIVE DEFINITE TRACER TRANSPORT SCHEME

THE NEW PARAMETER FOR THE GFS FORECAST PRESSURE GRIB
FILES IS:

MAX WIND GUST

SEVERAL PARAMETERS ARE BEING DELETED FROM THE GDAS ANALYSIS
PRESSURE GRIB FILES BECAUSE THEY ARE NOT VALID FOR THE
ANALYSIS DATASET AND HAVE NEVER PROVIDED PERTINENT
INFORMATION. THESE INCLUDE:

4 PRECIPITATION TYPES
CONVECTIVE PRECIPITATION RATE
LAND SEA MASK
LATENT HEAT FLUX
SENSIBLE HEAT FLUX
PRECIPITATION RATE
2M RH
2M SPECIFIC HUMIDITY
2M TEMPERATURE
BOUNDARY LAYER CLOUD COVER
LOW CLOUD COVER
CONVECTIVE CLOUD COVER
SKIN TEMPERATURE
SURFACE UPWARD LONG WAVE FLUX
SURFACE UPWARD SHORT WAVE FLUX HELICITY

THESE PARAMETERS ARE BEING DELETED FROM THE GLOBAL FORECAST
MODEL SIMULATED GOES GRIB FILE BECAUSE THEY WERE INCLUDED IN
ERROR. THESE FIELDS ARE AVAILABLE IN THE PGRB FILES:

MEAN SEA LEVEL PRESSURE
WAVE-5 GEOPOTENTIAL HEIGHT

ALL ACCUMULATED OR AVERAGED VALUES IN THE 192 HOUR PGRB
AND FLUX FILES WILL NOW BE OVER A 6 HOUR PERIOD INSTEAD OF
12 HOURS. THE FORMAT AND CONTENT OF THE 3 HOURLY FILES FROM
180 TO 192 HOURS WILL BE THE SAME AS THE FILES FROM 0 TO 180.
FOR THE FLUX FILE...THIS INCLUDES THE MAJORITY OF THE
PARAMETERS IN THE FILE. PARAMETERS CHANGING IN THE PGRB
FILE ARE:

2 M ABOVE GROUND MAX. TEMPERATURE
2 M ABOVE GROUND MIN. TEMPERATURE
SURFACE ALBEDO
SURFACE CLEAR SKY UV-B DOWNWARD SOLAR FLUX
SURFACE CATEGORICAL FREEZING RAIN
SURFACE CATEGORICAL ICE PELLETS
SURFACE CONVECTIVE PRECIPITATION RATE
SURFACE CATEGORICAL RAIN
SURFACE CATEGORICAL SNOW
ATMOSPHERIC COLUMN CLOUD WORK FUNCTION
SURFACE DOWNWARD LONG WAVE FLUX
SURFACE DOWNWARD SHORT WAVE FLUX
SURFACE UV-B DOWNWARD SOLAR FLUX
SURFACE GROUND HEAT FLUX
SURFACE LATENT HEAT FLUX
SURFACE PRECIPITATION RATE
LOW CLOUD BASE PRESSURE
LOW CLOUD TOP PRESSURE
MID-CLOUD BASE PRESSURE
MID-CLOUD TOP PRESSURE
HIGH CLOUD BASE PRESSURE
HIGH CLOUD TOP PRESSURE
SURFACE SENSIBLE HEAT FLUX
ATMOSPHERIC COLUMN TOTAL CLOUD COVER
BOUNDARY CLOUD LAYER TOTAL CLOUD COVER
LOW CLOUD COVER
MID-CLOUD COVER
HIGH CLOUD COVER
LOW CLOUD TOP TEMPERATURE
MID-CLOUD TOP TEMPERATURE
HIGH CLOUD TOP TEMPERATURE
SURFACE ZONAL GRAVITY WAVE STRESS
SURFACE ZONAL MOMENTUM FLUX
SURFACE UPWARD LONG WAVE FLUX
TOP OF ATMOSPHERE UPWARD LONG WAVE FLUX
SURFACE UPWARD SHORT WAVE FLUX
TOP OF ATMOSPHERE UPWARD SHORT WAVE FLUX
SURFACE MERIDIONAL GRAVITY WAVE STRESS
SURFACE MERIDIONAL MOMENTUM FLUX
SURFACE CONVECTIVE PRECIPITATION
SURFACE TOTAL PRECIPITATION
SURFACE LARGE SCALE PRECIPITATION

NOTE THAT FOR THE 192 HR PGRB PRODUCTS AVAILABLE ON NOAAPORT
AND IN AWIPS THE ACCUMULATIONS AND AVERAGES WILL REMAIN OVER
THE PREVIOUS 12 HOUR PERIOD UNTIL AWIPS IS MODIFIED TO
ACCOMMODATE THIS CHANGE.

THE FORMAT OF THE HALF AND ONE DEGREE PRESSURE GRIB FILES
WILL REMAIN THE SAME EXCEPT FOR THE CHANGES IN VARIABLES
LISTED ABOVE. THE SIZE OF THESE FILES WILL NOT CHANGE
SIGNIFICANTLY. WITH THE INCREASE IN MODEL RESOLUTION... THE
SIZE OF THE SIGMA COEFFICIENT FILES AND THE SURFACE FLUX
FILES WILL INCREASE SIGNIFICANTLY.

THESE CONTENT CHANGES WILL IMPACT ALL DISSEMINATION ROUTES:
NWS PUBLIC FTP SERVER...THE NCEP PUBLIC FTP SERVER...AND
NOAAPORT.

A SET OF TEST DATA IS AVAILABLE AT /USE LOWERCASE/ EXCEPT FOR
GFS AND T574L64:

FTP.EMC.NCEP.NOAA.GOV/GC_WMB/WX24FY/GFS_T574L64/GFS.20091217

A CONSISTENT PARALLEL FEED OF DATA WILL BECOME AVAILABLE ON
THE NCEP FTP SERVER ONCE THE MODEL IS RUNNING IN PARALLEL ON
THE NCEP CENTRAL COMPUTING SYSTEM IN MID APRIL. AT THAT TIME
THE PARALLEL DATA WILL BECOME AVAILABLE VIA THE FOLLOWING URL
/USE LOWERCASE/:

FTP://FTP.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PARA

DATA DELIVERY TIMING OF THE GFS WILL NOT BE IMPACTED BY THIS
IMPLEMENTATION.

NCEP ENCOURAGES ALL USERS TO ENSURE THEIR DECODERS ARE
FLEXIBLE AND ARE ABLE OF ADEQUATELY HANDLING CHANGES IN
CONTENT...PARAMETER FIELDS CHANGING ORDER...CHANGES IN THE
SCALING FACTOR COMPONENT WITHIN THE PRODUCT DEFINITION
SECTION /PDS/ OF THE GRIB FILES AND ANY VOLUME CHANGES WHICH
MAY OCCUR. THESE ELEMENTS MAY CHANGE WITH FUTURE NCEP MODEL
IMPLEMENTATIONS. NCEP WILL MAKE EVERY ATTEMPT TO ALERT USERS
TO THESE CHANGES PRIOR TO ANY IMPLEMENTATIONS.

IF YOU HAVE ANY QUESTIONS CONCERNING THESE CHANGES...PLEASE
CONTACT:

JOHN H. WARD
NCEP...GLOBAL MODELING BRANCH
CAMP SPRINGS MARYLAND
PHONE: 301-763-8000 X7185
EMAIL: JOHN.WARD@NOAA.GOV
OR
SHRINIVAS MOORTHI
NCEP...GLOBAL MODELING BRANCH
CAMP SPRINGS MARYLAND
PHONE: 301-763-8000 X7233
EMAIL: SHRINIVAS.MOORTHI@NOAA.GOV

NWS NATIONAL TECHNICAL IMPLEMENTATION NOTICES ARE ONLINE AT
/USE LOWERCASE/:

HTTP://WWW.WEATHER.GOV/OS/NOTIF.HTM

http://www.weather.gov/view/national.ph ... NS&sid=WSH

[srainhoutx]

Another thing about these upgrades will the positive effects on longer range forecasting of tropical systems. I believe wxman57 has stated after re analysis of Ike after the parallel upgrade, the GFS infact showed an Upper TX Coast strike instead of the Lower TX Coast/Corpus Christi. With the upgrades to the ECMWF, perhaps we are getting closer to actually having good data that will be a benefit in longer range forecasting regarding all weather situations be it winter, severe or tropical.

[wxman57]

I don't know about the longer range forecasts for TCs, but the 3-5 day forecast for Ike was much improved across the Gulf.

[wxman57]

I don't know about the longer range forecasts for TCs, but the 3-5 day forecast for Ike was much improved across the Gulf.

They history matched the model with the same data available to the operational GFS?

When they make changes to a model, they run the model with initialization data from a past weather event. Same data goes into the updated model as went into the original model for initialization. Otherwise, the comparison would not be valid.

[srainhoutx]

I'll bump this up as the Para GFS will become the Operational GFS as of 12Z today, 7/28/2010. A few delays, but today is the day.

[srainhoutx]

Steve hasn't posted about the horsefly in the soup yet?

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
227 PM EDT WED JUL 28 2010

NOTE TO ALL USERS. STARTING AT 12 UTC TODAY...A NEW GFS MODEL CAME
INTO EFFECT. ALTHOUGH THE MODEL SHOWS IMPROVEMENTS ON
PRECIPITATION FORECAST ACROSS MID LATITUDES...WE NOTED SOME
DEGRADATION ON THE WIND FORECAST ACROSS THE TROPICAL ATLANTIC AND
EASTERN CARIBBEAN... WHERE IT TENDS TO UNDER FORECAST INTENSITY OF
THE WINDS IN ASSOCIATION WITH TRADE WIND SURGES BELOW 700 HPA. THE
ERROR/ DIFFERENCE FROM ACTUAL OBSERVATIONS CAN BE AS HIGH AS 20
KNOTS. THIS IS A SYSTEMATIC PROBLEM WITH THE MODEL AND EXPECT IT
TO RECUR.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
306 AM CDT THU JUL 29 2010

.DISCUSSION...
GFS MEX MOS VIEWABLE ON LINE IS COOLER THAN THE GFS MEX MOS WE
RECEIVE IN OUR WORKSTATIONS. THE DAY SHIFT WILL HAVE TO FIND OUT
WHAT IS GOING ON...BUT THERE WAS A NEW VERSION OF THE GFS MODEL
ROLLED OUT ON WEDNESDAY AND THERE MAY BE A PROBLEM WITH THE MOS.
THAT BEING SAID...I HAVE OPTED TO LEAN TOWARD THE INTERNET
TEMPERATURES WHICH ARE COOLER...AND MORE IN LINE WITH THE MOS
GUIDANCE RECEIVED YESTERDAY. AT ANY RATE HIGHS SHOULD REACH TRIPLE
DIGITS MANY AREAS SATURDAY THROUGH NEXT THURSDAY.

[srainhoutx]

More troubles...

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
836 AM EDT THU JUL 29 2010

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI. A NEW GFS
BECAME OPERATIONAL DURING THE 12 UTC CYCLE YESTERDAY. AT UPPER
LEVELS IT RESOLVES A TUTT LOW TO THE NORTH/NORTHEAST OF THE
ISLANDS...WHERE IT IS EXPECTED TO MEANDER DURING THE NEXT FEW
DAYS. THE TUTT ALOFT IS TO ALLOW FOR MOISTURE TO SURGE ACROSS THE
NORTHEAST CARIBBEAN EARLY IN THE CYCLE...BUT THROUGH TOMORROW
MORNING THE PWS ARE TO DROP. IN CONTRAST TO THE OLD GFS...THE NEW
ONE DOES NOT FORESEE MUCH MOISTURE REACHING THE FORECAST AREA
DURING THE WEEKEND. AT LOW LEVELS THIS NEW MODEL SEEMS TO BE
HAVING PROBLEMS WITH PERTURBATIONS IN THE LOW LEVEL
EASTERLIES...AS IT IS NOT RESOLVING THESE WAVES TO THEIR FULL
EXTENT. I AM LOOKING FOR ANOTHER ALTERNATIVE TO THIS MODEL...AND
COMPLETELY OPEN TO SUGGESTIONS.

THE NEW MODEL IS VERY DRY BIASED...AND THIS SEEMS TO BE HAVING AN
IMPACT ON THE REGIONAL NAM...AS IT DEPENDS ON THE GFS TO
INITIALIZE THE BOUNDARY CONDITIONS. EXCEPT FOR SOME CONVECTION
TODAY...BOTH MODELS THEN TREND TOWARDS A VERY DRY PATTERN OVER THE
NEXT THREE TO FOUR DAYS. THE ECMWF IS NOT ANY BETTER...AS IT ALSO
SHOWS LIGHT RAINFALL PREVAILING OVER THE NEXT FEW DAYS...WITH BEST
CHANCE OF WEATHER LATE ON MONDAY.

CONSIDERING THE INFLUENCE OF THE TROUGH ALOFT...AND IMPACT OF
DIURNAL HEATING...WILL LIKELY SEE MORE CONVECTION THAN WHAT THESE
MODELS SHOW.