368
FXUS10 KWNH 270827
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
326 AM EST FRI DEC 27 2019
VALID DEC 27/0000 UTC THRU DEC 30/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH PREFERENCES/CONFIDENCE INTERVALS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
OVERALL PATTERN ACROSS THE CONUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: ECENS/ECMWF BLEND WITH SOME GFS/UKMET
CONFIDENCE: AVERAGE
08Z UPDATE: NO MAJOR DIFFERENCES SEEN IN THE REST OF THE 00Z
GUIDANCE (ECMWF/CMC/UKMET) COMPARED TO THE GFS/NAM AND EARLIER
ANALYSIS. THE 00Z NAM REMAINS A BIT OF AN OUTLIER WITH THE MIDWEST
SYSTEM BY DAY 3. BUT OVERALL THERE IS GOOD CLUSTERING WITH THE LOW
TRACKS WITH THE SYSTEM TO CONTINUE WITH THE PRIOR PREFERENCE.
---PREVIOUS DISCUSSION---
RELATIVELY AMPLIFIED SYNOPTIC PATTERN EXPECTED TO EVOLVE OVER THE
CONUS THROUGH THE NEXT 3 DAYS. LATEST WATER VAPOR IMAGERY SHOWS
WELL DEFINED CLOSED LOW OVER SOUTHERN CALIFORNIA WITH ANOTHER
SHORTWAVE TROUGH ACROSS SOUTHERN INTERIOR CANADA. DOWNSTREAM
RIDGING EXISTS ACROSS THE SOUTHEAST AND MID-ATLANTIC US. THE
CLOSED LOW WILL SLOWLY MOVE EASTWARD AND SPRAWL OUT OVER THE
CENTRAL U.S. THROUGH THE WEEKEND WITH A DEEPENING SURFACE LOW
EXPECTED TO DEVELOP BY SATURDAY MORNING THAT THEN TRACKS TOWARD
MSP BY SUNDAY. THE 00Z GFS IS ON THE NORTHERN SPREAD OF THE MODEL
SPREAD AND A TOUCH DEEPER ON SATURDAY COMPARED TO THE REST OF THE
MODELS. THE 12Z UKMET HOWEVER IS FASTER AND STRONGER WITH THE
500/250 MB FLOW AND ITS SURFACE LOW IS ON THE EASTERN PERIPHERY OF
THE SPREAD. COMPARED TO THE PREVIOUS CYCLES, THERE IS TIGHTENING
OF THE MODEL SOLUTIONS WITH BETTER AGREEMENT SEEN IN THE ENSEMBLE
LOW TRACK SPREAD, PARTICULARLY BY DAY 2/3. THE ECMWF/ECENS IS THE
MOST FAVORED CONSENSUS APPROACH, BUT THE CMC/UKMET/GFS OFFER SOME
UTILITY IN THE DAY 1/2 PERIOD. THE 00Z NAM BECOMES LESS USABLE
TOWARD DAY 3, AS ITS LOW TRACKS FURTHER TO THE NORTHWEST, WRAPPED
UP IN THE DEEPER AND FURTHER NORTH MID/UPPER LEVEL LOW. THE WPC
PREFERENCE IS FOR A BLEND OF THE ECMWF/ECENS MEAN WITH SOME
COMPONENTS OF THE GFS/UKMET.
FOR THE REST OF THE CONUS, THERE IS ABOVE AVERAGE AGREEMENT,
ESPECIALLY ACROSS THE EASTERN US WHERE PRIMARILY RIDGING ALOFT AND
SOUTHERLY FLOW WILL DOMINATE. ANOTHER ANOMALOUSLY STRONG CLOSED
LOW APPROACHES THE PACIFIC NORTHWEST SUNDAY/MONDAY AND HERE THERE
IS VERY GOOD AGREEMENT WITH THE MASS FIELDS. THE 12Z CMC IS A
TOUCH FAST WITH THE APPROACH OF THE SYSTEM BUT OVERALL A GENERAL
MODEL BLEND CAN BE USED.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
TAYLOR
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page