MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1105 AM EST SUN JAN 12 2014 VALID JAN 12/1200 UTC THRU JAN 16/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION...INCLUDING THE NAM AND GFS NO SIGNIFICANT INITIALIZATION ERRORS APPEAR TO BE IMPACTING THE SHORT RANGE FORECAST. ...CLOSED LOW SHEARING OUT OVER MEXICO/SOUTHERN TEXAS/GULF COAST STATES THROUGH MON... PREFERENCE: 00Z ECENS MEAN CONFIDENCE: AVERAGE A CLOSED LOW CURRENTLY EXITING THE GULF OF CA AND MOVING INTO WRN MEXICO WILL BE SHEARING OUT OVER THE NEXT 24 TO 36 HOURS AS ENERGY DIGS SEWD ACROSS THE GREAT BASIN AND TWD THE SRN PLAINS. THE SHEARING CLOSED LOW WILL OPEN INTO A PROGRESSIVE TROUGH AXIS AND THE ASSOCD VORT ENERGY WILL CROSS SOUTH TX AND THE WRN GULF COAST STATES MON BEFORE DAMPENING OUT. THERE ARE SOME IMPORTANT DIFFS AT THE SFC THAT EVOLVE AS THIS ENERGY SHEARS OUT. THE 00Z ECMWF/00Z UKMET AND 00Z GEM GLOBAL ALL APPEAR TO LOWER SFC PRESSURES MORE THAN THE 12Z NAM AND 12Z GFS. THE 00Z ECENS MEAN STRONGLY SUPPORTS THE NON-NCEP CAMP IN THIS REGARD. WHILE ALL OF THE MODELS DO SHEAR OUT THE VORT ENERGY ALOFT ACROSS THE GULF COAST ON MON...THERE SHOULD BE AT LEAST A DEFINABLE SFC WAVE THAT CROSSES THE NWRN GULF OF MEXICO AND APPROACHES THE CNTRL GULF COAST BY LATE MON. ADDITIONAL ENERGY APPROACHING FROM UPSTREAM WILL BEGIN INTERACTING AND DRIVING THIS WAVE AFTER MON. WILL PREFER A SOLN TWD THE 00Z ECENS MEAN ATTM ACCOUNTING FOR THE MODEL SPREAD AND CLUSTERING. ...PROGRESSIVE UPPER TROUGH DIGGING ACROSS THE PLAINS/MS VALLEY ON MON...AND AIMING FOR THE EASTERN U.S. TUES... ...SURFACE LOW TRACKING UP THE EASTERN SEABOARD ON TUES... PREFERENCE: 12Z GFS/00Z ECMWF BLEND CONFIDENCE: AVERAGE A PROGRESSIVE TROUGH CURRENTLY DIGGING ACROSS THE GREAT BASIN/ROCKIES WILL EJECT RAPIDLY ACROSS THE PLAINS AND MS VLY THROUGH MON AND THEN GRADUALLY BEGIN TO SHEAR OUT ACROSS THE EASTERN U.S. ON TUES IN LIEU OF STRONGER NRN STREAM HT FALLS/VORT ENERGY DIGGING SOUTH DOWN ACROSS THE MIDWEST TUES AND WED. OVERWHELMINGLY THE TREND HAS BEEN TO BE MORE PROGRESSIVE WITH THIS TROUGH AXIS. THE 12Z NAM AND 12Z GFS REMAIN THE MOST PROGRESSIVE...BUT THEY HAVE NOW BOTH TRENDED A LITTLE SLOWER AND STRONGER WITH THE TROUGH...AND ESP THE SRN PORTION OF THE TROUGH AS IT CROSSES THE GULF COAST STATES MON NIGHT AND THE SOUTHEAST ON TUES. THE 00Z ECMWF IS THE SLOWEST AND THE STRONGEST WITH THE DETAILS OF THE TROUGH...WITH THE 00Z UKMET AND 00Z GEM GLOBAL JUST A TAD WEAKER AND A LITTLE FASTER THAN THE ECMWF. MUCH OF THE DISAGREEMENT AT THIS POINT INVOLVES HOW STRONG VORT ENERGY WILL BE CROSSING THE GULF COAST STATES THAT IS SEEN DIGGING CURRENTLY SEWD ACROSS UT/CO IN THE LATEST WV/IR SAT IMAGERY. GOES-RGB AIRMASS IMAGERY SHOWS A WELL-DEFINED VORT OVER THIS AREA. BASED ON THE LATEST SAT TRENDS AND MODEL TRENDS...THE NAM AND GFS ARE LIKELY A LITTLE TOO WEAK/PROGRESSIVE WITH THIS PORTION OF THE TROUGH...BUT THE UKMET/GEM GLOBAL AND ESP THE ECMWF APPEAR TOO SLOW. WILL FAVOR A GFS/ECMWF COMPROMISE AS A RESULT...AND THIS WILL ALSO APPLY TO THE DEVELOPING SFC LOW NEAR THE GULF COAST/SOUTHEAST MON NIGHT AND UP ALONG THE EASTERN SEABOARD TUES AS THE LARGER SCALE ENERGY BEGINS SHEARING OUT AS IT GETS CAUGHT UP IN THE DEEPER LYR SWLY FLOW ALOFT ALONG THE EAST COAST. ...AMPLIFYING UPPER TROUGH/SURFACE LOW OVER THE MIDWEST/GREAT LAKES TUES AND WED... PREFERENCE: 12Z GFS/00Z ECMWF BLEND...FOR SURFACE LOW INTENSITY 00Z ECENS MEAN...FOR TROUGH DEPTH AND SURFACE LOW TIMING CONFIDENCE: AVERAGE THE MODELS ARE COMING AROUND TWD A SOLN REFLECTING A MORE AMPLIFIED UPPER TROUGH OVER THE MIDWEST/GREAT LAKES REGION ON TUES AND WED...WITH A VERY WELL-DEFINED SFC LOW AND ASSOCD FRONTAL ZONE. THE 12Z NAM AND 12Z GFS HAVE TRENDED A BIT STRONGER AND TWD THE ALREADY STRONGER 00Z ECMWF/00Z GEM GLOBAL SOLNS WITH THIS SYS. THE 00Z UKMET THOUGH IS SEEN AS A SLOW/DEEP OUTLIER. DESPITE THE TRENDS ON THE NAM AND GFS...THEY ARE LIKELY STILL A BIT TOO PROGRESSIVE AND ESP BY WED AS SFC LOW PRESSURE CROSSES THE GREAT LAKES REGION AND BEGINS LIFTING NEWD INTO THE ST LAWRENCE RIVER VLY. THE 00Z ECENS MEAN LEANS TWD A SLIGHTLY MORE PROGRESSIVE VERSION OF THE 00Z ECMWF. THE STRONGER SFC LOWS AS PER THE GFS/ECMWF APPEAR REASONABLE...BUT A LOW TRACK/TIMING OF THE 00Z ECENS MEAN WILL BE PREFERRED AS A COMPROMISE BETWEEN THE SLOWER ECMWF AND FASTER GFS. www.wpc.ncep.noaa.gov/html/model2.shtml... ORRISON