000 FXUS04 KWBC 290719 QPFPFD QUANTITATIVE PRECIPITATION FORECAST DISCUSSION NATIONAL CENTERS FOR ENVIRONMENTAL PREDICTION HYDROMETEOROLOGICAL PREDICTION CENTER...NWS...CAMP SPRINGS MD 215 AM EST TUE FEB 29 2000 PRELIM DAY1 AND DAY2 QPF DISCUSSION VALID MAR 1/1200 UTC AND MAR 2/1200 UTC REFERENCE AFOS GRAPHICS 94Q AND 98Q DAY1... OVRALL...MDLS IN GD AGREEMENT THRU MUCH OF THE U.S. ...NEW ENG... MDLS CONT TO FCST A STG CLSD LOW SE OF NEW ENG THAT WL CONT TO PROVIDE SOME BACKWASH LGT SNOWS TO ME THRU THE FIRST HALF OF THIS PD. ...CNTRL U.S... MDLS/SATL SHOW A STG PAC SHRTWV MOVG THRU THE CNTRL/SRN ROCKIES EARLY THIS MRNG THAT WL EJECT INTO THE CNTRL PLNS AND ACCEL NEWD BEFORE FINALLY PHASG WITH A STG MIDLVL SYS CROSSG SRN CANADA. THIS SYS HAS PLENTY OF STG MID/UPR LVL DYNAMICS...BUT THE LOLVL MSTR IS HAVG A HARD TIME WORKG NWD. SFC DWPTS REMAIN IN THE 30S THRU THE CNTRL/SRN PLNS AND 50S ARE OVR FAR SRN TX. BIG HGTS FALLS AND IMPRVS LEFT EXIT REGION UPR JET DYNAMICS SHLD PROVIDE ENUF LIFT TO SUPPORT SOME ELEV CNVCTN OVR THE CNTRL PLNS THAT WL LIFT QUICKLY NEWD. THE SPEED OF MOVMENT AND LACK OF DECENT MSTR WL KEEP AMTS ON THE LGT SIDE. SOME COLD AIR ON THE BACKEDGE OF THE PCPN SHIELD MGT SUPPORT SOME MIXD RN/SN...BUT TEMPS ARE QUITE WRM SO ACCUM WL BE LGT. ...WRN U.S.... SATL/MDLS SHOW THE NEXT POTENT ERN PAC SYS MOVG TWD NRN CA EARLY THIS MRNG. THERE IS A WEAK PLUME OF DEEPER MSTR ASSOC WITH THIS SYS...BUT IT CONTS TO WEAKEN WITH TIME AS THE MIDLVL SYS PROGRESSES EWD. MDLS SHOW THE SYS SPLITG WITH SOME ENERGY MOVG INTO THE NRN ROCKIES...WHILE THE MAIN MIDLVL SYS DROPS INTO THE SWRN U.S.. THIS SHLD HELP FOCUS THE HVIER PCPN OVR CA. ONSHORE FLOW WL CONT TO INCRS EARLY TDA...BUT WL THEN WEAKEN THIS AFTN AS THE MIDLVL ENERGY PASSES THRU THE REGION. SO XPCT THE HVIER PCPN TO OCCUR EARLY THIS PD AND BE FOCUSD INTO THE FAVORED OROGRAPHIC REGIONS OF THE CNTRL SIERRA. LATER TNGT AS THE MIDLVL SYS MOVS INTO THE GRT BASIN WE SHLD SEE SOME LGT PCPN WITH SNOW AT THE HIER ELEVS. DAY2... LOCAL WORKSTATION PROBLEMS HAVE MADE IT DIFFICULT TO VIEW MUCH OF THE NEW MODEL RUN. CONSEQUENTLY THERE IS NOT MUCH CHANGE FROM THE PREVIOUS THINKING IN PART ALSO BECAUSE THE MODELS SEEM FAIRLY CONSISTENT. ALONG THE W COAST THE NEXT SYSTEM IS FCST TO BE APPROACHING NEAR THE END OF THE PERIOD. WE FAVOR A SLIGHTLY SLOWER MOVEMENT THAN THE AVN SINCE THIS HAS VERIFIED BETTER RECENTLY WITH THESE FEATURES. ENERGY APPEARS TO BE SPLITTING AGAIN WITH THE NRN SHORTWAVE MOVING TOWARD VANCOUVER ISLAND WHILE THE SRN VORT IS HEADED FOR NRN CA. WE HAVE SLOWED THE SPREAD OF THE PCPN INTO NRN CA AND REDUCED THE AMOUNTS INTO NW WASH GIVEN THE WEAKENING SYSTEM. THE CLOSED LOW FCST TO MOVE THRU THE SW WILL PRODUCE MDT AMOUNTS OF SNOW ACROSS THE FAVORED SW FACING SLOPES AS THE SYSTEM MOVES THRU THE REGION. SLOWER HAS SEEMED BETTER WITH THESE SYSTEMS LATELY BUT THE NEW AVN IS A LITTLE FASTER THAN PREVIOUS. THE CANADIAN IS SIMILAR AND PERHAPS THIS GIVES A BETTER WAVELENGTH SPACING BETWEEN SYSTEMS. WE GENERALLY GO ALONG WITH DEVELOPING UPSLOPE ACROSS SERN CO AND CONVECTION AHEAD OF THE COLD FNT OVER NW TX. FINALLY THE STRONG SHORTWAVE MOVING THRU THE ERN LAKES WILL SPREAD SHWRS AHEAD OF IT INTO NEW ENGLAND WITH BEST AMOUNTS CLOSE TO THE LAKES. ECKERT/LEATHERS/FORECAST OPERATIONS BRANCH GRAPHICS AVAILABLE ON THE WEB AT H.TTP://WWW.HPC.NCEP.NOAA.GOV