450
FXUS10 KWNH 091832
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
231 PM EDT WED OCT 09 2019
VALID OCT 09/1200 UTC THRU OCT 13/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
09/12Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..EAST COAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: ANY OF THE OPERATIONAL MODELS
CONFIDENCE: ABOVE AVERAGE
A STACKED, CLOSED LOW FORMING THE LOWER PART OF A REX BLOCK WILL
LINGER WITH RAIN OVER NEW ENGLAND BEFORE BEING PRODDED ALONG BY
THE UPSTREAM CENTRAL U.S. CYCLONE. THE 12Z GFS TRENDED MORE IN
LINE WITH THE OTHER OPERATIONAL MODELS, MAKING FOR A STRONG
CONSENSUS AND THE ABILITY TO USE ANY OF THE OPERATIONAL MODELS FOR
THIS SYSTEM THROUGH DAY 3.
..CENTRAL U.S. MID-LATITUDE CYCLONE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: ANY OF THE OPERATIONAL MODELS, DROPPING THE GFS AFTER
12/00Z
CONFIDENCE: ABOVE AVERAGE
A VERY DEEP, 2 TO 3 STANDARD DEVIATION TROUGH, WILL SPIN UP INTO A
LARGE SCALE CYCLONE WITH LOW PRESSURE TRACKING FROM COLORADO
TOWARD NORTHERN MINNESOTA DURING THE MATURING PHASE, AND THEN
LINGERING IN PLACE OVER MINNESOTA WHILE A SHORTWAVE RIDGE BUILDS
OVER THE TOP IN CANADA. POTENTIALLY RECORD-BREAKING OCTOBER
SNOWFALL IS POSSIBLE IN PARTS OF THE PLAINS, ALONG WITH STRONG
WINDS. THE MODELS ARE IN VERY GOOD AGREEMENT WITH THIS LARGE SCALE
STORM WITHIN THE UPPER AIR NETWORK. THE *BEST* CONSENSUS CLUSTERS
AROUND THE ECMWF ENSEMBLE MEAN, AND SO WOULD INCLUDE MOST OF THE
OPERATIONAL MODELS THROUGH DAY 3. THE EXCEPTION IS THE GFS WHICH
TENDS TO CHANGE SHAPE ON DAY 3, WITH ENERGY ROTATING AROUND AND
DRAGGING THE MATURE CYCLONE TOWARD THE GREAT LAKES SOMEWHAT
UNREALISTICALLY.
..WEST COAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF 12Z NAM / ECMWF / CANADIAN
CONFIDENCE: AVERAGE
A COMPLICATED MERGER OF TWO STREAMS AROUND 145 DEGREES WEST LEADS
EVENTUALLY TO A MORE CONSOLIDATED OPEN TROUGH APPROACHING THE WEST
COAST BY DAY 3. SOME SOLUTIONS SPLIT THE ENERGY AGAIN, WITH
EMPHASIS ON A SOUTHERN STREAM TROUGH ANCHORED OFF CALIFORNIA, AND
A LOW AMPLITUDE NORTHERN STREAM WAVE PUNCHING INTO THE NORTHWEST.
WE PREFER SOLUTIONS THAT ARE CLOSER TO THE ECMWF MEAN, GIVEN ITS
HANDLING OF THE NORTH AMERICAN PATTERN AS A WHOLE, AND BASED ON
SYNOPTIC REASONING INVOLVING DIFFERENTIAL ADVECTION OVER THE
PACIFIC. THE OPERATIONAL ECMWF MAY BE A BIT TOO SLOW AND
CONSOLIDATED, AND THE NAM A BIT TOO FAST, BUT A BLEND OF THE TWO
GETS CLOSE TO THE EC MEAN, AND IS A DECENT REPRESENTATION OF
CONSENSUS. ONE COULD THROW THE 12Z CANADIAN IN THERE FOR GOOD
MEASURE.
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML
BURKE
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page