961
FXUS10 KWNH 141827
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
126 PM EST FRI FEB 14 2020
VALID FEB 14/1200 UTC THRU FEB 18/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH PREFERENCES & CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..MIDWEST/MISSISSIPPI VALLEY AND EAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
EXCEPTION: GFS/ECMWF BLEND FOR QPF ALONG GULF/SOUTHEAST
CONFIDENCE: ABOVE AVERAGE
19Z UPDATE: THE 12Z NON-NCEP SUITE SHOWED LITTLE SIGNIFICANT
VARIATION TO CHANGE FROM INITIAL PREFERENCE/THINKING
---PRIOR DISCUSSION---
LARGE SCALE TROF IS FINALLY EXITING THE EAST COAST TODAY WITH ONLY
THE LINGERING SHOWERS ALONG THE FRONT ACROSS FLORIDA, FOLLOWED BY
THE COLD ARCTIC AIRMASS/HIGH PRESSURE WHICH EVOLVE VERY SIMILARLY
WITHIN THE GUIDANCE SUITE. THIS HIGH WILL BE SHUNTED ALONG DUE TO
THE APPROACH OF A STRONGER SHORTWAVE MOVING THROUGH CENTRAL CANADA
THAT CLIPS THE GREAT LAKES LATE SATURDAY INTO SUNDAY. ACROSS THIS
REGION, GENERAL MODEL BLEND REMAINS SOLID PREFERENCE WITH HIGH
CONFIDENCE; HOWEVER, THE VERY DISTANT INFLUENCES OF WEAK RETURN
WESTERN GULF MOISTURE SUPPORTS THUNDERSTORM ACTIVITY ALONG THE
CENTRAL GULF COAST ON SUNDAY THAT SLIDE INTO THE SOUTHEAST. GIVEN
THE WEAKNESS OF THE FLOW FROM A SYNOPTIC STANDPOINT THERE IS
MODEST MODEL UNCERTAINTY IN THE QPF PLACEMENT; BUT A GFS/ECWMF
BLEND SEEMS TO BE BEST COMBINATION FOR SOME INCREASED CONFIDENCE.
...PACIFIC NW SYSTEM SAT/SUN,REACHING NORTHERN/CENTRAL PLAINS
MONDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS/ECMWF/CMC BLEND AFTER 17.00Z
CONFIDENCE: SLIGHTLY ABOVE TO ABOVE AVERAGE
19Z UPDATE: THE 12Z UKMET IS GENERALLY A BIT WEAKER BUT FAST WITH
THE LEADING EDGE OF THE HEIGHT-FALLS CROSSING INTO THE NORTHERN
PLAINS. THIS IS OPPOSITE TO THE OVER-AMPLIFICATION OF THE NAM,
BUT IN BEING WEAK/FAST IS MUCH FURTHER NORTH LEADING TO ISSUES IN
PLACEMENT COMPARED TO THE INITIAL PREFERENCE. THE 12Z ECMWF DID
SLOW A BIT COMPARED TO THE INITIAL PREFERENCE AND IS NOW, MORE
TRADITIONALLY, SLOWER THAN THE GFS; YET, THE ECMWF IS FLATTER AND
MORE PROGRESSIVE THAN THE OVER-AMPLIFIED NAM/UKMET WITH THE
UPSTREAM ENERGY DIGGING INTO THE NORTHERN GREAT BASIN. THE CMC IS
SIMILAR TO ITS 00Z RUN AND IS VERY CLOSE TO THE THE GFS OVERALL.
SO ALL IN ALL, WILL KEEP WITH INITIAL PREFERENCE OF THE
GFS/ECMWF/CMC AT SLIGHTLY ABOVE TO ABOVE AVERAGE CONFIDENCE.
---PRIOR DISCUSSION---
IT IS THE NEXT PACIFIC NORTHWEST SYSTEM COMING IN LATE SATURDAY TO
SUNDAY THAT HAD SHOWN THE GREATEST UNCERTAINTY YESTERDAY. THE
ECMWF TRENDED SLOWER, YESTERDAY ALONG WITH THE CMC AND IT APPEARS
THE GFS/GEFS/NAM HAS SHIFTED EASTWARD AS AN OVERALL BETTER
COMPROMISE OF TIMING. THIS BRINGS MUCH STRONGER
AGREEMENT/CONFIDENCE ESPECIALLY IN TIMING THROUGH SUNDAY. THERE
REMAINS SOME TIMING/AMPLITUDE DIFFERENCES BY DAY 3 AS THE SYSTEM
SPILLS IN THE NORTHERN AND CENTRAL PLAINS. THE 12Z NAM AND 00Z
UKMET ARE A BIT MORE AGGRESSIVE WITH GREATER SHARPENING OF THE
TROF OVER THE GREAT BASIN/UTAH BY THE VERY END OF THE PERIOD WHICH
WILL LEAD TO AN ELONGATION/LAGGING RELATIVE TO THE MORE
PROGRESSIVE ECMWF/CMC SOLUTIONS WITH THE GFS MORE IN THE MIDDLE,
YET FAVORING THE ECMWF/CMC SLIGHTLY MORE. HOWEVER, IT IS THE
PARTICULARLY AGGRESSIVE STRENGTH OF THE SHORTWAVE IN THE NORTHERN
STREAM WITH THE 12Z NAM THAT MAKES IT A CLEAR OUTLIER. AS SUCH
WILL FAVOR REMOVAL OF THE NAM ACROSS THE PLAINS INTO THE WEST
AFTER ABOUT 17.00Z MONDAY AND LIMIT THE 00Z UKMET INFLUENCE ACROSS
THE SNAKE RIVER PLAIN INTO THE GREAT BASIN/SOUTHERN ROCKIES ABOUT
17.12Z IN THE PREFERRED BLEND. STILL THESE ARE FAIRLY SMALL
DIFFERENCES SO THE CONFIDENCE IS FAIRLY HIGH IN PREFERENCE
THROUGHOUT THE FORECAST PERIOD.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
GALLINA
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