MODEL DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP

DEVELOPING CYCLONE OFF THE SOUTHEAST COAST...

THE NAM IS FURTHER TO THE S AND W THAN THE GFS THRU MUCH OF THE
PERIOD AND IS AROUND 25 MB DEEPER AT THE SFC BY THE END OF DAY 2.
THE 00Z ECMWF/12Z CMC/UKMET GLOBAL ARE FASTER THAN THE NAM TO
CARRY THE SYSTEM WWD...BUT THE ECMWF SOLUTION IS DISCOUNTED GIVEN
THAT ITS 12HR FORECAST SHOWED A POSITION WELL WEST OF WHAT WAS
OBSERVED AT 12Z...WHILE THE CMC/UKMET INITIALIZED THE SYSTEM TOO
FAR W AS WELL. GIVEN THE POOR INITIALIZATIONS OF THE MODELS...DO
NOT HAVE A GREAT DEAL OF CONFIDENCE IN ANY PARTICULAR
SOLUTION...

BUT IN COMPARISON TO THE REMAINING MODELS THE GFS
APPEARS TOO WEAK WITH THE MID LVL RIDGE TO THE N OF THE SYSTEM AND
IS THEREFORE TOO SLOW TO MOVE THE SYSTEM WWD...WHILE ALLOWING THE
SYSTEM TO MOVE TOO FAR TO THE N. A MORE PROGRESSIVE/AMPLIFIED/SLY
SOLUTION THAN THE GFS WOULD BETTER FIT THE MODEL CONSENSUS. NOT
READY TO BUY INTO A SOLUTION AS PROGRESSIVE AS THE ECMWF GIVEN ITS
POOR FORECAST OR THE CMC/UKMET GIVEN THEIR POOR INITIALIZATIONS.

NOT SURE A SYSTEM AS DEEP AS THE NAM IS IN ORDER EITHER GIVEN ITS
TENDENCY TO OVER-AMPLIFY ANY SYSTEM OF A TROPICAL NATURE. THAT
SAID...THE CURRENT HPC/TPC THINKING IS FOR A TRACK FURTHER TO S
AND DEEPER THAN THE GFS...BUT NOT QUITE AS PROGRESSIVE AS THE CMC
GLOBAL/UKMET/00Z ECMWF.

THERE ARE ALSO ISSUES WITH THE STRENGTH/WRN EXTENT
OF THE MID LVL RIDGE OVER THE WRN ATLC AND ERN/SERN CONUS.
TELECONNECTION-FAVORED UPSTREAM CONFIGURATION FAVORS A HEALTHY
SERN RIDGE CLOSER TO WHAT IS DEPICTED IN THE ECMWF/RECENT NCEP
MEANS/06Z-12Z GFS. GUIDANCE CONTINUES TO SHOW THE POTENTIAL FOR
LOW PRESSURE OFF THE SERN COAST TO DEVELOP AND LIFT NWD ALONG THE
EAST COAST. THE 12Z GFS HAS SHIFTED NOTICEABLY WWD TOWARD THE
DOMINANT CLUSTER OF OTHER MODEL GUIDANCE.

FINAL MANUAL FCST http://www.hpc.ncep.noaa.gov/medr/day3nav.html

DEPICTS THE HPC/TPC COORDINATED TRACK FOR THIS FEATURE.