049
FXUS10 KWNH 310639
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
238 AM EDT SUN MAY 31 2020
VALID MAY 31/0000 UTC THRU JUN 03/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING INITIAL PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
UPPER LEVEL TROUGH AND COLD FRONT ACROSS THE EASTERN U.S.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND THROUGH 00Z TUESDAY, THEN 12Z
ECMWF/GFS/UKMET BLEND
CONFIDENCE: ABOVE AVERAGE
AN AMPLIFIED UPPER LEVEL TROUGH WILL CONTINUE TO BUILD IN ACROSS
THE EASTERN U.S. THROUGH THE BEGINNING OF THE WEEK, WITH THE
SURFACE COLD FRONT CONTINUING TO MOVE FARTHER OFFSHORE AND A HIGH
QUALITY AIRMASS SETTLING IN ACROSS MUCH OF THE REGION. SIMILAR TO
LAST NIGHT, THE MODELS ARE IN VERY GOOD AGREEMENT THROUGH ABOUT
00Z TUESDAY WITH THE CMC REMAINING SLIGHTLY WEAKER WITH THE
TROUGH. BY TUESDAY MORNING, AN UPPER LOW IS LIKELY TO EVOLVE FROM
THE TROUGH OVER THE NOVA SCOTIA REGION, WITH THE GFS AND UKMET
INDICATING THE BEST POTENTIAL FOR THIS BY 00Z WEDNESDAY. A BLEND
OF THE ECMWF, GFS, AND UKMET SHOULD WORK WELL BEYOND 00Z TUESDAY
UPPER LEVEL LOW SLOWLY LIFTING FROM NORTHERN MEXICO INTO THE
SOUTHERN PLAINS SATURDAY-TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
THE MODELS ARE IN GENERALLY GOOD AGREEMENT INDICATING A BROAD
UPPER LOW LIFTING NORTH FROM NORTHERN MEXICO INTO WEST TEXAS BY
TUESDAY MORNING, BEFORE CONTINUING NORTHEAST TOWARDS OKLAHOMA ON
TUESDAY NIGHT. THERE IS NOT MUCH OF A SURFACE REFLECTION OF THIS
IN TERMS OF THE SEA LEVEL PRESSURE FIELDS. A GENERAL MODEL BLEND
WILL SUFFICE FOR THIS UPPER LEVEL LOW AND TROUGH.
SHORTWAVE LIFTING ACROSS THE PACIFIC NORTHWEST AND THEN ACROSS
SOUTHERN CANADA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-UKMET BLEND
CONFIDENCE: AVERAGE
OVERALL, MODELS ARE IN GOOD AGREEMENT SHOWING A STRONG SHORTWAVE
OVER OREGON AND LIFTING NORTHEAST ACROSS WASHINGTON AND THEN
ALBERTA BY SUNDAY NIGHT. MODELS REMAIN IN GOOD AGREEMENT INTO
EARLY MONDAY AS THE SYSTEM CONTINUES FARTHER EAST ACROSS
SOUTH-CENTRAL CANADA. SIGNIFICANT MODEL DIFFERENCES DO NOT EVOLVE
UNTIL EARLY TUESDAY AS SYSTEM BEGINS TO MOVE SOUTH OF HUDSON BAY.
AS THE SYSTEM BEGINS TO ROUND THE TOP OF THE UPPER RIDGE, THE
UKMET BECOMES A NOTED OUTLIER WITH A CLOSED SYSTEM DEVELOPING
SOUTH OF HUDSON BAY AND MUCH SLOWER THAN THE OTHER GUIDANCE.
UPPER LEVEL TROUGH MOVING FROM THE PACIFIC NORTHWEST TO THE
NORTHERN PLAINS AND UPPER MIDWEST MONDAY-TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND THROUGH 12Z MONDAY THEN,
GFS/ECMWF COMPROMISE 12Z MONDAY-00Z WEDNESDAY
CONFIDENCE: AVERAGE
WITH RESPECT TO TIMING, THE MODELS ARE IN GENERALLY GOOD AGREEMENT
THROUGH EARLY MONDAY AS THE SYSTEM MOVES EAST FROM THE EASTERN
PACIFIC INTO THE PACIFIC NORTHWEST. HOWEVER, DIFFERENCES QUICKLY
DEVELOP AS THE SYSTEM MOVES DOWNSTREAM, WITH THE UKMET, ECMWF AND
THE 00Z EC ENSEMBLE MEAN BECOMING NOTABLY FASTER THAN THE NCEP
GUIDANCE THROUGH THE NORTHERN ROCKIES INTO THE PLAINS AND UPPER
MIDWEST. WHILE THE GFS IS STILL AMONG THE SLOWER SOLUTIONS, IT
HAS TRENDED FASTER COMPARED TO ITS 00Z AND PREVIOUS 12Z SOLUTIONS.
AND WHILE STILL FASTER THAN THE GFS, THE 12Z ECMWF IS SLOWER THAN
ITS 00Z RUN, SUGGESTING THE TWO MODELS MAY BE MOVING TOWARD A
CONSENSUS.
CUTOFF LOW DEVELOPING WEST OF SOUTHERN CALIFORNIA AND NORTHERN
BAJA MONDAY-TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: UKMET/ECMWF/12Z EC ENSEMBLE MEAN
CONFIDENCE: AVERAGE
ENERGY DROPPING SOUTHEAST ACROSS THE EASTERN PACIFIC IS EXPECTED
TO DEVELOP A CLOSED LOW OFF OF THE SOUTHERN CALIFORNIA AND
NORTHERN BAJA COASTS EARLY NEXT WEEK. LATEST GUIDANCE SHOWS SOME
DIFFERENCES WITH RESPECT TO THE POSITION OF THE LOW'S CENTER, WITH
THE NCEP GUIDANCE GENERALLY A LITTLE EAST OF THE UKMET, ECMWF AND
THE 12Z EC ENSEMBLE MEAN. TRENDS IN THE GFS SUPPORT LEANING
TOWARD THE UKMET, ECMWF AND 12Z EC MEAN.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
HAMRICK
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