Prognostic Meteorological Discussion
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FXUS10 KWNH 220512
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
111 AM EDT MON MAY 22 2017

VALID MAY 22/0000 UTC THRU MAY 25/1200 UTC

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

00Z PRELIMINARY MODEL EVALUATION/PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...CLOSED LOW OVER THE UPPER MS VALLEY AND GREAT LAKES TODAY...
...COLD FRONT MOVING ACROSS THE CENTRAL AND EASTERN U.S....
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE

THE MODELS ARE IN GOOD AGREEMENT WITH THE EVOLUTION OF THIS LARGE
SCALE SYNOPTIC SYSTEM. A GENERAL MODEL BLEND WILL BE PREFERRED TO
RESOLVE ANY LINGERING SMALLER SCALE DIFFERENCES.


...SHORTWAVE CROSSING THE GREAT BASIN/CENTRAL ROCKIES TODAY...
...EJECTING OUT INTO THE SOUTHERN PLAINS ON MON...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE

OVERALL THERE REMAINS GOOD MODEL AGREEMENT WITH THIS FEATURE.


...SHORTWAVE MOVING INTO MT EARLY MON AROUND THE BACKSIDE OF THE
UPPER MS VALLEY AND SOUTHERN CANADA CLOSED LOW...
...ENERGY AMPLIFYING OVER THE MIDWEST AND MOVING TOWARDS THE EAST
COAST THROUGH WED...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 0Z GFS AND 12Z ECMWF BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE MODELS CONTINUE TO ADVERTISE A WELL-DEFINED SHORTWAVE DIGGING
SOUTHEAST TODAY ACROSS THE MT HIGH PLAINS AND THEN AROUND THE
SOUTHWEST FLANK OF THE LARGER SCALE UPPER MS VALLEY/SOUTHERN
CANADA CLOSED LOW BY TUES WITH THE ENERGY AMPLIFYING AS IT ARRIVES
OVER THE MIDWEST. THIS ENERGY EVENTUALLY HELPS DIG THE TROUGH OVER
THE CENTRAL PORTION OF THE COUNTRY BY TUES...WITH THE TROUGH
MOVING TOWARDS THE EAST COAST BY LATER WED INTO THURS. THE 0Z NAM
CONTINUES TO STAND OUT AS AN OUTLIER WITH THE EVOLUTION OF THIS
TROUGH...BEING QUICKER IN CLOSING OFF A DEEP LAYER LOW AND SLOWER
PROGRESSING THE TROUGH EASTWARD. THE 12Z UKMET/GEM ALSO HANDLE THE
SHORTWAVE ENERGY WITHIN THE TROUGH IN WHAT APPEARS TO BE A LESS
LIKELY WAY...WITH THE UKMET A LITTLE TOO SLOW WITH THE OVERALL
PROGRESSION AND THE GEM TOO QUICK. WHILE DIFFERENCES DO EXIST
BETWEEN THE GFS AND ECMWF SOLUTIONS...THERE OVERALL EVOLUTION ARE
PROBABLY THE MOST SIMILAR AMONGST THE GUIDANCE...AND THUS FOR NOW
WOULD PREFER TO STICK CLOSE TO A BLEND OF THE 0Z GFS AND 12Z ECMWF
SOLUTIONS.


...SOUTHERN STREAM WAVE ARRIVING ACROSS SOUTHEAST TX ON MON...
...ADDITIONAL SHORTWAVE ENERGY MOVING ACROSS THE GULF
COAST/SOUTHEAST MON/TUE...
...SURFACE LOWS TRAVERSING THE GULF COAST INTO THE SOUTHEAST
TUES...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z UKMET AND 12Z ECMWF
CONFIDENCE: AVERAGE

THE MODELS REMAIN IN AGREEMENT IN BRINGING A SOUTHERN STREAM WAVE
ACROSS NORTHERN MEXICO AND EASTWARD INTO TX BY EARLY MON. AS THIS
ENERGY...ALONG WITH ADDITIONAL ENERGY DROPPING SOUTHEAST AROUND
THE BASE OF THE CENTRAL U.S. TROUGH... INTERACTS WITH A STALLED
FRONT NEAR THE SOUTHEAST TX COAST...ONE OR MORE WAVES OF LOW
PRESSURE SHOULD DEVELOP ALONG THIS FRONT AND THEN ADVANCE
EAST-NORTHEAST...MOVING JUST INLAND ACROSS THE CENTRAL GULF COAST
BEFORE THEN LIFTING NORTHEAST UP ACROSS THE INTERIOR SOUTHEAST
U.S. AND MID-ATLANTIC IN AN ELONGATED FASHION THROUGH LATE TUES
INTO WED.

HAVE GENERALLY SEEN SOME CONVERGENCE AMONGST RECENT GFS/ECMWF
RUNS...WITH THE GFS TRENDING A BIT SLOWER AND WEAKER WITH THE LEAD
WAVE...AND THE ECMWF TRENDING A LITTLE QUICKER. HOWEVER STILL
THINK THE GFS IS PROBABLY PUTTING TOO MUCH EMPHASIS ON THE LEAD
WAVE AND LOW. APPEARS TO BE SOME CONVECTIVE FEEDBACK ISSUES IN THE
GFS TODAY ACROSS THE LOWER MS VALLEY AND SOUTHEAST THAT COULD BE
EXACERBATING THIS PROBLEM. FOR NOW WOULD CONTINUE TO PREFER A
SOLUTION CLOSER TO THE MORE CONSISTENT ECMWF/UKMET. THE 0Z NAM IS
MORE SIMILAR TO THE GFS...AND THE 12Z GEM IS OVERALL STRONGER AND
FURTHER INLAND WITH THE SYSTEM AND DOES NOT HAVE MUCH SUPPORT AT
THIS TIME.


...UPPER TROUGH MOVING ACROSS THE PACIFIC NORTHWEST ON TUES...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

A RATHER STRONG UPPER TROUGH IS EXPECTED TO BE DIGGING SOUTHEAST
TOWARD THE PACIFIC NORTHWEST ON TUES FROM THE GULF OF AK. THIS
ENERGY WILL ADVANCE INLAND AND CROSS THE NORTHERN ROCKIES ON WED.
MODEL CLUSTERING IS GOOD ENOUGH WITH THIS SYSTEM TO RECOMMEND A
GENERAL MODEL BLEND FOR THE TIME BEING.


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

CHENARD

$$





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