Prognostic Meteorological Discussion
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10

000
FXUS10 KWNH 271721
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
120 PM EDT FRI MAY 27 2016

VALID MAY 27/1200 UTC THRU MAY 31/0000 UTC

...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...

12Z NAM/GFS EVALUATION WITH PRELIMINARY MODEL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR
SHORT RANGE FORECASTS.


SYSTEM PIVOTING THROUGH THE NORTHWEST THROUGH EARLY SATURDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: ECMWF/GFS COMPROMISE
CONFIDENCE: BELOW AVERAGE

THE GFS HAS CONTINUED TO BE A DEEPER OUTLIER WITH THE MID LEVEL
TROUGH OVER MT BY THE END OF THE PERIOD (00Z TUE). THE NAM AND CMC
MEANWHILE REMAIN THE SLOWEST MODELS...WHILE THE 00Z ECMWF IS A BIT
FASTER/FLATTER WITH THIS WAVE. IN LOOKING AT THE MEANS AT 500
MB...BOTH THE GEFS AND ECMWF MEANS ARE FLATTER WITH THE WAVE (AS
EXPECTED)...AND ARE MATCHED UP WELL WITH THEIR RESPECTIVE
OPERATIONAL RUNS IN TERMS OF THE TIMING. AT THIS POINT...A BLEND
OF THE GFS (TIMING AND STRENGTH) APPEARS TO BE THE MORE PRUDENT
CHOICE...ALBEIT A LOWER THAN NORMAL CONFIDENCE ONE.


CLOSED MID-UPPER LOW MOVING INTO THE SOUTHWEST SUNDAY-MONDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: A NON-UKMET GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE.

NO REAL NOTEWORTHY ISSUES IN TERMS OF HOW THE MODELS ARE HANDLING
THIS SYSTEM...
EXCEPT FOR THE FACT THAT THE 12Z UKMET IS A BIT FASTER WITH THE
CLOSED 500 MB CIRCULATION INTO NORTH-CENTRAL AZ BY MONDAY MORNING.


INITIALLY CLOSED MID-UPPER LOW OVER THE CENTRAL HIGH PLAINS
LIFTING NE
INTO THE UPPER MS VALLEY-UPPER GREAT LAKES SAT NIGHT AND SUN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS/ECMWF/CANADIAN COMPROMISE
CONFIDENCE: AVERAGE

BOTH THE 12Z NAM AND UKMET ARE TOO WEAK (FLAT)/TOO PROGRESSIVE/TOO
FAR NORTH WITH THIS FEATURE BY LATE SATURDAY INTO SUNDAY.


CONVECTIVE LOW APPROACHING SOUTHEAST COAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CANADIAN/NON-NAM COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THERE IS INCREASING SPREAD AMONG THE MODELS AFTER 48 HRS (AFTER
12Z SUN) WITH RESPECT TO TH EVENTUAL WHEREABOUTS AND STRENGTH WITH
THE SURFACE CIRCULATION ONCE REACHING THE SOUTHEAST COAST. THE
27/12Z CANADIAN REMAINED ON THE NORTHERN FRINGE OF THE GUIDANCE
SPREAD...WHILE THE 12Z NAM INDICATED THE LOW WEAKENING AND
BECOMING ABSORBED INT THE RIDGE ON SUN. AT THIS POINT...A BLEND OF
THE 12Z GFS/UKMET WITH THE 00Z ECMWF APPEARS MOST REASONABLE.


...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...

...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...


HURLEY


$$




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.