847
FXUS10 KWNH 291926
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
226 PM EST WED JAN 29 2020
VALID JAN 29/1200 UTC THRU FEB 02/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH FINAL PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..OVERALL SYNOPSIS
AN ACTIVE PATTERN OVER SOUTHEAST AND PACIFIC NORTHWEST THROUGH
SATURDAY.
...PRIMARY MID-LEVEL TROUGH OVER THE FOUR CORNERS NOW, CROSSING
SOUTH TEXAS THURSDAY AND THE SOUTHEAST FRIDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF 29/12Z ECMWF/UKMET WITH SOME GFS/CMC
CONFIDENCE: AVERAGE
THIS LEADING SHORTWAVE TROUGH OFF A RIDGE OVER THE INTERIOR
PACIFIC NORTHWEST SWINGS ACROSS NORTHERN MEXICO TONIGHT AND
THURSDAY THEN SOUTH TEXAS THURSDAY NIGHT. A SECONDARY TROUGH DIGS
IN BEHIND THURSDAY NIGHT, WEAKENING THE MID-LEVEL ENERGY AS IT
CROSSES THE SOUTHEAST FRIDAY. THE 12Z GFS REMAINS FARTHER NORTH
WITH DAY 2 QPF ALONG THE WESTERN/CENTRAL GULF COAST COMPARED TO
THE 12Z ECMWF/UKMET WHICH BOTH TRENDED SOUTH A BIT. THE 12Z NAM
CONTINUES TO DIVERGE FROM CONSENSUS THURSDAY NIGHT WITH THE
INTERACTION OF THE PRIMARY AND SECONDARY SHORTWAVE TROUGHS OVER
THE SOUTHERN PLAINS, SO IT IS NOT PREFERRED. THE 12Z CMC HAS SPED
UP A BIT AND IS NOW REASONABLE ENOUGH TO BE INCLUDED IN THE BLEND.
...SOUTHERN PART OF SECONDARY MID-LEVEL TROUGH DIGGING DOWN THE
ROCKIES FROM CANADA TO MEXICO TONIGHT THROUGH THURSDAY NIGHT...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF 29/12Z ECMWF/UKMET WITH SOME 12Z GFS/CMC
CONFIDENCE: AVERAGE
THE SOUTHERN END OF THIS SHORTWAVE TROUGH CROSSING THE INTERIOR
PACIFIC NORTHWEST RIDGE IS IN DECENT AGREEMENT AMONG THE 12Z
SUITE. THE 12Z ECMWF SHIFTED EAST AND IS MUCH MORE INLINE WITH THE
12Z GFS/UKMET WHICH FAVOR THE IMMEDIATE LEE SIDE OF THE ROCKIES
THROUGH THURSDAY NIGHT. THIS SOUTHERN END FEATURE THEN SPLITS OFF
INTO MEXICO FRIDAY WITH A TROUGH OVER SOUTHERN TEXAS. THE 12Z NAM
FAVORS A NORTHERN STREAM LOW OVER THE CENTRAL/SOUTHERN PLAINS AND
IS AN OUTLIER. THE 12Z CMC IS MORE LIKE CONSENSUS WITH THE TRACK
AND CAN BE INCLUDED NOW.
...NORTHERN PORTION SECONDARY MID-LEVEL TROUGH CROSSING THE
CENTRAL PLAINS THURSDAY NIGHT/FRIDAY AND PUSHING OFF THE SOUTHEAST
COAST SATURDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF 29/12Z ECMWF/UKMET WITH SOME 12Z GFS/CMC
CONFIDENCE: BELOW AVERAGE
COMPLEX INTERACTION OF THE NORTHERN STREAM PORTION OF A SECONDARY
SHORTWAVE CROSSING THE INTERIOR PAC NW RIDGE THAT BREAKS OFF LATE
THURSDAY OVER THE NORTHERN PLAINS AND INTERACTS WITH A TROUGH OVER
THE GREAT LAKES FRIDAY INTO SATURDAY. HOWEVER, THERE IS DECENT
AGREEMENT THAT THE RESULTING TROUGH PUSHES OFF THE SOUTHEAST COAST
AND STAYS OFFSHORE AS IT LIFTS NORTH SATURDAY NIGHT/SUNDAY. THE
12Z NAM IS FARTHER SOUTH THAN THE PREFERRED CONSENSUS OF THE
EC/GFS/UKMET. THERE IS STILL DECENT RUN-TO-RUN VARIABILITY OF THIS
FEATURE AND HOW THE PARTS INTERACT AND THE THERMAL DIFFERENCES SO
THIS REMAINS A WAIT AND SEE FOR A SOLID SOLUTION TO BE BORNE OUT.
THE 12Z CMC IS MORE IN LINE WITH CONSENSUS, SO A SOLUTION MAY BE
COMING TOGETHER. ONE NOTE ABOUT THE 12Z ECMWF IS IT MAINTAINS A
FLATTER TROUGH OVER FLORIDA WHICH PRODUCES HEAVIER DAY 3 PRECIP
THAN CONSENSUS WHICH LIMITS IS USAGE OVER THAT REGION.
...LONGWAVE TROUGH APPROACHING THE WEST COAST OF CANADA FRIDAY
NIGHT/SATURDAY AND DOWNSTREAM ATMOSPHERIC RIVER INTO THE PACIFIC
NORTHWEST LATE THURSDAY INTO SATURDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 29/12Z ECMWF/UKMET AND 00Z ECENS BLEND WITH SOME
29/12Z NAM
CONFIDENCE: AVERAGE
THE PASSAGE OF A SHORTWAVE AND ACCOMPANYING COLD FRONT INTO
BRITISH COLUMBIA THURSDAY WILL BRING INITIALLY ZONAL FLOW INTO
WESTERN CANADA THAT AMPLIFIES AS RIDGING INCREASES AHEAD OF AN
UPSTREAM SHORTWAVE FRIDAY. ENSEMBLE MEANS AND THE REMAINING
DETERMINISTIC CONSENSUS CONTINUE TO INDICATE THAT THE 29/12Z
GFS/CMC ARE TOO FAR NORTH... SO A BLEND OF THE 29/00Z ECENS AND
29/12Z ECMWF/UKMET/NAM REMAINS IS RELATIVE AGREEMENT FOR THE
TROUGH POSITION AND THE DOWNSTREAM ATMOSPHERIC RIVER MOVING INTO
THE PACIFIC NORTHWEST.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
JACKSON
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