Prognostic Meteorological Discussion
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000 FXUS10 KWNH 241844 PMDHMD MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 244 PM EDT FRI JUN 24 2016 VALID JUN 24/1200 UTC THRU JUN 28/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... ...AN EVALUATION OF THE 12Z MODEL GUIDANCE ALONG WITH FINAL PREFERENCES/FORECAST CONFIDENCE... ...INITIAL SHORTWAVE TRACKING THROUGH THE MID-ATLANTIC THIS AFTERNOON... ...REMNANT VORTICITY SPINNING WELL OFF THE NEW ENGLAND COAST... FINAL PREFERENCE: BLEND OF THE 12Z GFS/GEFS MEAN FORECAST CONFIDENCE: SLIGHTLY BELOW AVERAGE THE TRAILING PIECE OF SHORTWAVE ENERGY WITHIN A LARGER-SCALE TROUGH WILL PUSH OFF THE DELMARVA/NJ COAST BY THIS EVENING. AS THE SYSTEM CONTINUES TO PUSH AWAY FROM THE EASTERN SEABOARD...THE 12Z NAM HAS MAINTAINED A MORE ELONGATED/SOUTHWARD-EXTENDING TROUGH WHICH SUPPORTS AN INVERTED SURFACE TROUGH CLOSER TO THE CAROLINA COAST. NO DETERMINISTIC/ENSEMBLE SOLUTION SHOWS THIS IDEA AT THIS TIME. FURTHER OUT IN THE FORECAST PERIOD...SOME OF THE SHORTWAVE IS FORECAST TO PINCH OFF AND POSSIBLY DRIFT WESTWARD. THE 582-DM SPAGHETTI PLOTS THE PAST COUPLE OF MODEL CYCLES HAVE INDICATED THE ECMWF ENSEMBLE MEMBERS ARE THE FARTHEST SOUTH/WEST OF THE OTHER MODELS. WHILE ON THEIR OWN...THE 12Z ECMWF DID MAKE A NORTH/EAST NUDGE AWAY FROM THAT SOLUTION BUT WILL CONTINUE TO MAINTAIN THE PREVIOUS MORE OFFSHORE PREFERENCE. ...COMPACT UPPER LOW PUSHING ACROSS THE NORTHERN ROCKIES SATURDAY MORNING... ...ASSOCIATED SURFACE CYCLONES/COLD FRONT... FINAL PREFERENCE: BLEND OF THE 12Z GFS/ECMWF WITH THE 12Z GEFS MEAN FORECAST CONFIDENCE: AVERAGE WATER VAPOR IMAGERY DEPICTED A WELL ESTABLISHED UPPER TROUGH ADVANCING INTO EASTERN WA/NORTHERN ID. THIS SYSTEM IS FORECAST TO CONTINUE ACCELERATING EASTWARD GENERALLY STRADDLING THE INTERNATIONAL BORDER WITH CANADA. THE GENERAL MODEL DIFFERENCES NOTED IN THE PREVIOUS MODEL DISCUSSION HAVE SOMEWHAT DIMINISHED AS THE 12Z CMC TRENDED QUICKER WHILE THE 12Z UKMET ADJUSTED FROM ITS PREVIOUSLY MORE AGGRESSIVE SURFACE SOLUTION. TOWARD THE END OF THE FORECAST...THE 12Z ECMWF NOTABLY SHIFTED SLOWER TO WHERE IT IS ACTUALLY NOW TO THE WEST OF THE 12Z GFS. THERE ARE OBVIOUSLY STILL SOME UNCERTAINTIES IN THE FORECAST TO IRON OUT. WILL BLEND THE 12Z GFS/ECMWF SOLUTIONS WHILE INCORPORATING THE 12Z GEFS MEAN TO ACCOUNT FOR THESE RUN-TO-RUN UNCERTAINTIES. ...TUTT CELL LIFTING ACROSS THE RIO GRANDE RIVER VALLEY... FINAL PREFERENCE: GENERAL MODEL COMPROMISE FORECAST CONFIDENCE: SLIGHTLY ABOVE AVERAGE A BROAD CIRCULATION CURRENTLY LIFTING OUT OF THE EASTERN MX WILL BEGIN TO MOVE ACROSS THE RIO GRANDE RIVER AND INTO THE BIG BEND AREA BY 25/1800Z. ALL MODELS AGREE THAT THE FEATURE SHOULD CONTINUE TO SHEAR WHILE MOVING NORTHWARD THROUGH A WEAKNESS IN A BROAD 594-DM RIDGE. THERE APPEARS TO BE CLOSE ENOUGH AGREEMENT HERE TO SUPPORT A GENERAL MODEL COMPROMISE. ...LOW AMPLITUDE SHORTWAVE APPROACHING THE PACIFIC NORTHWEST COAST BY LATE SUNDAY... FINAL PREFERENCE: GENERAL MODEL COMPROMISE FORECAST CONFIDENCE: AVERAGE AS THE PRIMARY BAND OF MID-LEVEL HEIGHT FALLS SLIDE AWAY FROM THE PACIFIC NORTHWEST...ANOTHER FEATURE EMERGES OFF THE EASTERN PACIFIC. BY SUNDAY AFTERNOON...AN ELONGATED/LOW-AMPLITUDE IMPULSE BEGINS TO APPROACH THE OR/WA COAST. LIKE THE PRECEDING DAY...THE 00Z CMC/UKMET ARE ON THE MUCH SLOWER SIDE OF THE SPREAD. HOWEVER...THE ARRIVAL OF THE 12Z GUIDANCE HAS BROUGHT SOLUTIONS MUCH CLOSER TO ONE ANOTHER WHICH WOULD SUPPORT SOME FORM OF COMPROMISE AMONG THE MODELS. ...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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