Prognostic Meteorological Discussion
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000
FXUS10 KWNH 280634
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
234 AM EDT SUN MAY 28 2017

VALID MAY 28/0000 UTC THRU MAY 31/1200 UTC

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

00Z MODEL EVALUATION WITH PRELIMINARY PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
INITIALIZATION ERROR NEAR THE MO/KS/AR/OK BORDER JUNCTION
DISCUSSED BELOW.


UPPER TROUGH MOVING INTO THE WEST COAST TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: COMPROMISE OF THE AVAILABLE GUIDANCE
CONFIDENCE: ABOVE AVERAGE

THE GUIDANCE AGREES ON THE TIMING OF THIS SYSTEM, BUT DEPTH ISSUES
ARE SEEN ALOFT, WITH THE 00Z NAM STRONGER THAN THE OTHER GUIDANCE
-- ITS TYPICAL BIAS.  A COMPROMISE OF THE AVAILABLE GUIDANCE
SHOULD IRON OUT THIS ISSUE EFFECTIVELY, WHICH IS PREFERRED WITH
ABOVE AVERAGE CONFIDENCE.


WAVE RACING ACROSS THE OH VALLEY/WESTERN NY SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: COMPROMISE OF THE AVAILABLE GUIDANCE
CONFIDENCE: ABOVE AVERAGE

AN INITIALIZATION ERROR APPEARS IMPORTANT NEAR THE MO/KS/AR/OK
BORDER JUNCTION APPEAR IMPORTANT TODAY.  WHILE THE 00Z SURFACE
ANALYSIS INDICATES A 1003 HPA LOW NEAR TULSA OK, THE SCALE OF THE
SYSTEM IN THE 12Z UKMET IS OVERSIZED -- THE 12Z ECMWF/00Z NAM HAVE
THE RIGHT SPATIAL RESOLUTION FOR IT, BUT ONE HAS TO USE A
COMPROMISE OF THE TWO SOLUTIONS TO GET THE RIGHT SPOT AT 00Z.

THE 12Z UKMET ISSUES BECOME SIGNIFICANT AS IT INTENSIFIES THE LOW
LIKE A TROPICAL CYCLONE OVERLAND -- ENDING UP WITH A 990 HPA
CYCLONE MOVING ACROSS BUFFALO.  SINCE 2015, THE UKMET HAS GONE
OVERBOARD WITH WARM CORE CONVECTIVE SYSTEMS OVER LAND, TROPICAL
AND OTHERWISE, SO IT IS LIKELY MUCH TOO STRONG.  A COMPROMISE OF
THE REMAINDER OF THE GUIDANCE INTO SUNDAY NIGHT IS PREFERRED WITH
THIS SYSTEM WITH ABOVE AVERAGE CONFIDENCE.

0630Z UPDATE - THE UKMET HAS BACKED OFF SIGNIFICANTLY FROM ITS
PREVIOUSLY SOLUTION...PUTTING IT MUCH MORE IN LINE WITH THE
REMAINING DETERMINISTIC GUIDANCE.


SURFACE LOW TRACKING OUT OF THE MID ATLANTIC MONDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: COMPROMISE OF THE AVAILABLE GUIDANCE
CONFIDENCE: ABOVE AVERAGE

BECAUSE OF ITS ISSUES IN THE MIDWEST/WESTERN NY, THE 12Z UKMET WAS
TOO FAR NORTH WITH THIS SYSTEM`S TRACK.  A COMPROMISE OF THE 00Z
GFS, 00Z NAM, 12Z CANADIAN, AND 12Z ECMWF IS ADVISED WITH ABOVE
AVERAGE CONFIDENCE.

0630Z UPDATE - THE UKMET HAS BACKED OFF SIGNIFICANTLY FROM ITS
PREVIOUSLY SOLUTION...PUTTING IT MUCH MORE IN LINE WITH THE
REMAINING DETERMINISTIC GUIDANCE.

DEEP LAYERED CYCLONE WOBBLING ABOUT ONTARIO
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS/UKMET/ECMWF COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE 00Z NAM AND ECMWF TAKE OFF TO THE NORTH WITH THIS SYSTEM ON
TUESDAY, WITH THE NAM LYING WELL NORTH OF THE 18Z GEFS/12Z ECMWF
ENSEMBLE MEAN SOLUTIONS.  WITH GLOBAL ENSEMBLE SUPPORT, PREFER A
COMPROMISE OF THE 00Z GFS/ECMWF/UKMET WITH ABOVE AVERAGE
CONFIDENCE.


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

ROTH/PEREIRA

$$





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