Prognostic Meteorological Discussion
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FXUS10 KWNH 011657
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1256 PM EDT FRI AUG 01 2014

VALID AUG 01/1200 UTC THRU AUG 05/0000 UTC

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

...AN EVALUATION OF THE 12Z NAM/GFS ALONG WITH PRELIMINARY
PREFERENCES/FORECAST CONFIDENCE...

THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 12Z
NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS.


...MEAN TROF PERSISTING ACROSS THE EASTERN U.S...
...COASTAL BAROCLINIC ZONE...

PRELIMINARY PREFERENCE: BLEND OF THE 12Z GFS/00Z ECMWF
FORECAST CONFIDENCE: SLIGHTLY ABOVE AVERAGE

A BROAD UPPER TROF WILL REMAIN A MAINSTAY FEATURE ACROSS THE
EASTERN U.S. DURING THE FORESEEABLE FUTURE. THE CORE OF THE LOWER
HEIGHTS CURRENTLY ACROSS SOUTHERN HUDSON BAY WILL LIFT UP INTO THE
HIGHER LATITUDES WITH A LOOSER GRADIENT SETTING UP FOR THE WEEKEND
AND INTO EARLY NEXT WEEK. ONE RATHER EXTREME SOLUTION OUT THERE IS
THE 12Z NAM WHICH CARRIES A POTENT UPPER LOW/SURFACE WAVE FROM THE
BAHAMAS ALONG THE SOUTHEASTERN U.S. ON SUNDAY/MONDAY. AS WAS THE
CASE YESTERDAY...THE 12Z NAM IS THE FARTHEST WEST SOLUTION WHICH
IS DISPLACED FROM THE 09Z SREF. MEANWHILE...SIMILAR TO THEIR
CONTINUITY...THE 00Z CMC/UKMET REMAIN ON THE FAR EASTERN SIDE OF
THE SPREAD WITH REGARD TO UPPER TROF POSITION. SUCH DIFFERENCES
ALSO REFLECT SIMILARLY WITH THE PLACEMENT OF THE COASTAL FRONTAL
ZONE. IT APPEARS THE 12Z GFS HAS JUMPED A BIT EAST TOWARD THE 00Z
ECMWF/ECMWF ENSEMBLE MEAN SOLUTION LEAVING THE 06Z GEFS MEAN OFF
TOWARD THE WEST. WOULD PREFER TO STAY CLOSER TO THE MIDDLE OF THE
SPREAD WHICH WOULD BE MORE ALONG THE LINES OF THE 12Z GFS/00Z
ECMWF.


...MID-LEVEL ENERGY TRACKING FROM THE PACIFIC NORTHWEST INTO THE
UPPER INTERMOUNTAIN WEST...

PRELIMINARY PREFERENCE: GENERAL MODEL COMPROMISE
FORECAST CONFIDENCE: AVERAGE

MODELS DEPICT A SERIES OF SMALL-SCALE SHORTWAVES MOVING FROM THE
PACIFIC NORTHWEST INTO THE UPPER INTERMOUNTAIN WEST THE NEXT
COUPLE OF DAYS. THESE IMPULSES WILL TRAVERSE ABOVE A BROAD RIDGE
ANCHORING THE SOUTHWESTERN SECTION OF THE COUNTRY. OVERALL...THE
NCEP GUIDANCE IS A HAIR FASTER WITH THIS SYSTEM BUT THE
DIFFERENCES AS A WHOLE ARE RATHER SMALL THEREBY RESULTING IN A
GENERAL MODEL COMPROMISE HERE.



...DISTURBANCE LIFTING FROM THE DESERT SOUTHWEST TO THE CENTRAL
GREAT BASIN SUNDAY/MONDAY...

PRELIMINARY PREFERENCE: A NON-00Z CMC MODEL COMPROMISE
FORECAST CONFIDENCE: SLIGHTLY ABOVE 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 03/1200Z. BY THE
FOLLOWING MORNING...THE SYSTEM WILL LIFT INTO THE CENTRAL GREAT
BASIN WITH AGREEMENT ACROSS THE BOARD WITH THE EXCEPTION OF THE
00Z CMC WHICH IS SLIGHTLY OFF TOWARD THE SOUTHWEST. WILL RECOMMEND
A NON-00Z CMC MODEL COMPROMISE GIVEN THE REASONABLE CLUSTER SEEN
84 HOURS INTO THE FORECAST.


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

RUBIN-OSTER

$$




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