Prognostic Meteorological Discussion
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000
FXUS10 KWNH 300650
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
249 AM EDT TUE MAY 30 2017

VALID MAY 30/0000 UTC THRU JUN 02/1200 UTC

...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...

00Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE

SPLITTING UPPER TROUGH MOVING INTO THE WESTERN U.S ON WED
----------------------------------------------------------
PREFERENCE: MODEL CONSENSUS
CONFIDENCE: ABOVE AVERAGE

OVERALL...THE LATEST DETERMINISTIC GUIDANCE REMAINS IN GENERALLY
GOOD AGREEMENT WITH THIS SYSTEM...SHOWING A NORTHERN STREAM TROUGH
MOVING FROM THE PACIFIC NORTHWEST ON WED THROUGH THE NORTHERN
ROCKIES INTO THE HIGH PLAINS BY EARLY FRI.  MEANWHILE...A
SHORTWAVE WITHIN THE SOUTHERN STREAM IS EXPECTED TO DIG SOUTH
ACROSS CA INTO THE DESERT SOUTHWEST AND NORTHWESTERN MEX THU-FRI.


DEEP LAYERED CYCLONE DRIFTING NORTH ACROSS ONTARIO AND WAVES
PROGRESSING ACROSS THE GREAT LAKES
----------------------------------------------------------
PREFERENCE: GFS/ECMWF
CONFIDENCE: AVERAGE

AS THE PARENT CIRCULATION INTERACTS WITH A PAIR OF SHORTWAVES
DIGGING SOUTH FROM THE NORTHERN TERRITORIES...THE MODELS CONTINUE
TO DISAGREE ON THE EVOLUTION OF A DEEP LAYERED CYCLONE CENTERED
OVER EASTERN CANADA.  MOST SHOW THE PARENT CIRCULATION PHASING
WITH A COMPACT LOW DROPPING SOUTH INTO NORTHERN ONTARIO BY LATE
WED.  THIS PHASED SYSTEM IS THEN SHOWN BY MOST OF THE GUIDANCE
DRIFTING ACROSS SOUTHERN QUEBEC AS SECOND SHORTWAVE DIVES SOUTH
BEHIND IT INTO WESTERN ONTARIO BY LATE THU.  GUIDANCE DISAGREES ON
THE TIMING AND AMPLITUDE OF THIS SECOND SHORTWAVE...AS WELL AS THE
DEGREE OF PHASING THAT WILL OCCUR BETWEEN IT AND THE DOWNSTREAM
LOW OVER QUEBEC.  THE GFS AND ECMWF HAVE MOVED INTO BETTER
AGREEMENT...SHOWING LESS PHASING BETWEEN THE SYSTEMS...WITH THE
LOW OVER QUEBEC DRIFTING FURTHER EAST TOWARD NEW BRUNSWICK AND
NORTHERN MAINE EARLY FRI.  THE UKMET AND NAM DO NOT TAKE LOW AS
FAR EAST...WHILE DIGGING A MORE AMPLIFIED UPSTREAM WAVE FURTHER
SOUTH NORTH OF THE GREAT LAKES.  THE MORE SIGNIFICANT OUTLIER IS
THE CANADIAN GLOBAL...WHICH IS SLOWER WITH THIS SECOND UPSTREAM
WAVE AND IN TURN LEAVES THE UPPER LOW WELL WEST OF THE
DETERMINISTIC CONSENSUS LATE IN THE PERIOD.   BUT
OVERALL...DESPITE THE NUMEROUS DIFFERENCES ALOFT ACROSS
CANADA...THE SPREAD ACROSS MUCH OF THE GREAT LAKES/OH VALLEY INTO
THE NORTHEAST/MID ATLANTIC IS LESS PRONOUNCED AND MAY BE LARGELY
ADDRESSED WITH A GENERAL MODEL COMPROMISE.

SOUTHERN STREAM TROUGH EJECTING NORTHEAST FROM MEXICO INTO NM AND
TEXAS
----------------------------------------------------------
PREFERENCE: NON-12 UTC CANADIAN COMPROMISE
CONFIDENCE: AVERAGE

OVERALL...THE MODELS ALL GENERALLY INDICATE SIMILAR
SOLUTIONS...SHOWING A FAIRLY WELL-DEFINED WAVE LIFTING NORTH FROM
NORTHERN MEXICO INTO WEST TEXAS AND NEW MEXICO ON WED.  MOST SHOW
A WEAKENING SYSTEM SHEARING EAST ACROSS NORTH TEXAS AND OKLAHOMA
ON THU.

WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML... /ALL LOWER CASE/
WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML... /ALL LOWER CASE/

PEREIRA

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