096
FXUS10 KWNH 101837
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
236 PM EDT FRI APR 10 2020
VALID APR 10/1200 UTC THRU APR 14/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION...WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..DEEP CYCLONE EXITING THE NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE ANOMALOUSLY DEEP CLOSED LOW IMPACTING THE NORTHEAST TODAY WILL
BE EJECTING NORTHEAST ACROSS SOUTHEAST CANADA TONIGHT AND
SATURDAY. THE GUIDANCE SHOWS VERY GOOD LARGE SCALE AGREEMENT WITH
THE MASS-FIELD EVOLUTION, SO A GENERAL MODEL BLEND WILL BE
PREFERRED AS THIS SYSTEM BEGINS TO EXIT.
..CLOSED LOW EXITING THE SOUTHWEST
..ENERGY EJECTING TOWARD THE LOWER MS VALLEY BY SUNDAY
..POWERFUL SURFACE LOW OVER THE GREAT LAKES BY MONDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS/12Z UKMET/00Z ECMWF AND ECENS/GEFS BLEND
CONFIDENCE: AVERAGE...THROUGH 60 HOURS
BECOMING BELOW AVERAGE...AFTER 60 HOURS
THE LARGE, SLOW-MOVING CUT-OFF SOUTHERN STREAM LOW OVER SOUTHERN
CALIFORNIA WILL GRADUALLY MOVE TOWARD SOUTHERN AZ/NM ON SATURDAY
AND THEN OPEN UP INTO A PROGRESSIVE SHORTWAVE ACROSS THE SOUTHERN
PLAINS BY EARLY SUNDAY. BY LATE SUNDAY, THIS ENERGY WILL BEGIN TO
TAKE ON A NEGATIVE TILT OVER THE LOWER MS VALLEY AND QUICKLY REACH
THE OH VALLEY BY EARLY MONDAY. THE ENERGY COUPLED WITH INCREASING
INFLUENCE FROM A STRONG NORTHERN STREAM TROUGH AMPLIFYING OVER THE
UPPER MIDWEST SUNDAY AND MONDAY WILL LEAD THE WAY FOR A POWERFUL
SURFACE CYCLONE TO LIFT OVER LOWER MI ON MONDAY. THE GUIDANCE HAS
GENERALLY COME INTO BETTER AGREEMENT WITH THE EVOLUTION OF THE
SHORTWAVE ENERGY ACROSS THE SOUTH, WITH MULTI-CYCLE TRENDS OF THE
GFS COMING IN SLOWER AND TOWARD THE NON-NCEP MODEL CAMP. TODAY'S
DIFFERENCES ARE MUCH MORE FOCUSED ON THE OH VALLEY AND GREAT LAKES
REGION.
THE 12Z NAM ENDS UP WITH A SOMEWHAT FASTER SHORTWAVE PROGRESSION
UP NORTH ACROSS THE OH VALLEY INTO LOWER MI, AND A LOW TRACK ON
THE LEFT SIDE OF THE DETERMINISTIC MODEL SPREAD. THE 12Z CMC
OVERALL IS AN OUTLIER IN BEING THE WEAKEST SOLUTION BUT ALSO
REFLECTS A TRACK FARTHER NORTHWEST ACROSS THE WESTERN GREAT LAKES.
THE 12Z ECMWF THOUGH WHICH HAD BEEN FARTHER SOUTHEAST HAS MADE A
SIZABLE JUMP WITH ITS TRACK TO THE NORTHWEST AND TOWARD THE
NAM/CMC CAMP. HOWEVER, THE 00Z ECENS/12Z CMCE SUITES AND
ESPECIALLY THE 00Z/06Z/12Z GEFS SUITES FAVOR A SOLUTION THAT IS
QUITE DEEP, BUT WITH A LOW TRACK STILL SOUTHEAST OF THE 12Z
NAM/CMC/ECMWF SOLUTIONS. HAVING SAID THAT, THERE IS A CAMP OF EC
ENSEMBLE MEMBERS THAT DO TAKE THE LOW OFF FARTHER TO THE
NORTHWEST, AND THE KEY FOR THIS TO VERIFY WILL BE THE INTRUSION OF
STRONGER NORTHERN STREAM ENERGY FROM THE UPPER MIDWEST AND
SUBSEQUENT PHASING. THE NEW ECMWF REFLECTS THIS POSSIBILITY.
CONFIDENCE IS SOMEWHAT LIMITED LATE IN THE PERIOD AS THERE IS ROOM
FOR A SOMEWHAT DEEPER LOW TO TRACK FARTHER WEST OVER THE GREAT
LAKES, BUT BASED ON THE LATEST CLUSTERING FROM THE 12Z GFS, 12Z
UKMET, AND FORMER 00Z ECMWF SOLUTIONS, A BLEND OF THESE SOLUTIONS
WILL BE PREFERRED, AND IN CONJUNCTION WITH THE ENSEMBLE MEANS.
..AMPLIFYING UPPER TROUGH OVER THE NORTHERN U.S. BY MONDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE MODELS BRING AMPLIFYING SHORTWAVE/JET ENERGY SOUTHEASTWARD
FROM THE SOUTHERN COAST OF AK AND THE ADJACENT YUKON TERRITORY
DOWN ACROSS SOUTHWEST CANADA AND OUT ACROSS THE NORTHERN ROCKIES
AND NORTHERN PLAINS BY SUNDAY. BY MONDAY, THIS ENERGY WILL AMPLIFY
INTO A DEEP LONGWAVE TROUGH OVER THE NORTHERN U.S. THAT WILL
GRADUALLY PHASE WITH THE AFOREMENTIONED SOUTHERN STREAM ENERGY
EJECTING ACROSS THE SOUTH AND LIFTING TOWARD THE GREAT LAKES
REGION. THE MODELS ARE IN GOOD AGREEMENT WITH THE DETAILS OF THE
LONGWAVE TROUGH EVOLUTION. SO, A GENERAL MODEL BLEND WILL BE
PREFERRED WITH THIS.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
ORRISON
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