Prognostic Meteorological Discussion
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FXUS10 KWNH 020634
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
234 AM EDT SAT AUG 02 2014

VALID AUG 02/0000 UTC THRU AUG 05/1200 UTC

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

00Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 00Z
NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS.


MEAN TROF PERSISTING ACROSS THE EASTERN U.S.
COASTAL BAROCLINIC ZONE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z GFS/ECMWF/UKMET
CONFIDENCE: AVERAGE

ALL OF THE 00Z MODELS APPEAR SIMILAR TO EACH OTHER EARLY ON WITH A
WEAK LOW PRESSURE WAVE TRACKING SOUTH OF NEW ENGLAND LATER TODAY
THROUGH SUN OFF OF NEW ENGLAND.

BY LATER TONIGHT...THE NAM IS QUITE A BIT STRONGER WITH A SURFACE
LOW APPROACHING FLORIDA WHICH THEN TRACKS CLOSE TO THE SOUTHEAST
COAST MON/TUE. WHILE THE NAM POSITION APPEARS REASONABLE GIVEN ITS
PLACEMENT AMONG THE DETERMINISTIC/ENSEMBLE DISTRIBUTION...THERE IS
NOT ANY SUPPORT FOR THE STRONGER NAM AT THIS TIME. THE 00Z CMC
ALSO SPINS UP A STRONG SURFACE LOW NEAR THE MID-ATLANTIC COAST MON
MORNING...BUT A DIFFERENT LOW THAN WHAT THE NAM DEVELOPS...WITH
THE CMC ALSO UNSUPPORTED AT THIS TIME.

A GFS/ECMWF/UKMET BLEND WILL BE USABLE FOR THE ENTIRE 84 HOUR
SHORT RANGE PERIOD.


MID-LEVEL ENERGY TRACKING FROM THE PAC NW INTO SWRN CANADA TONIGHT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 00Z GFS COMPROMISE
CONFIDENCE: AVERAGE

MODELS DEPICT A SERIES OF SMALL-SCALE SHORTWAVES MOVING FROM THE
PACIFIC NORTHWEST INTO SWRN CANADA WITH BROAD AGREEMENT IN THE
MID-LEVELS. HOWEVER...THE 00Z GFS IS OUT OF AGREEMENT FROM THE
OTHER MODELS REGARDING LOW PRESSURE IN ERN MONTANA SUN NIGHT. A
NON 00Z GFS COMPROMISE IS PREFERRED IN THIS REGION DUE TO THEIR
DECENT AGREEMENT.


DISTURBANCE LIFTING FROM THE DESERT SOUTHWEST TO THE CENTRAL GREAT
BASIN SUNDAY/MONDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 00Z NAM COMPROMISE
CONFIDENCE: AVERAGE

A BROAD AXIS OF SHORTWAVE ENERGY AND ASSOCIATED MOISTURE IS
FORECAST TO EMERGE FROM NORTHWESTERN MEXICO INTO THE DESERT
SOUTHWEST BY EARLY IN THE WEEKEND. IN GENERAL...MODELS AGREE WITH
THE GENERAL POSITION OF THIS ENERGY THROUGH 12Z/04. AFTER
12Z/04...SOME TIMING DIFFERENCES APPEAR REGARDING THE EJECTION OF
THE UPPER FEATURE EWD ACROSS THE INTERMOUNTAIN WEST. THE 12Z CMC
IS SLOWEST WHILE THE 00Z NAM IS QUICKEST. THE MODELS HAVE SHOWN A
SLOWING TREND WITH THIS FEATURE OF THE PAST 24 HOURS...BUT GIVEN A
LACK OF SUPPORT FOR THE SLOWEST 12Z CMC...AND THE 00Z CMC JOINING
THE REMAINING NON NAM CONSENSUS...A NON 00Z NAM COMPROMISE WILL BE
PREFERRED.


...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...
...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...


OTTO

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