FXUS04 KWBC 012310 PAA QPFPFD QUANTITATIVE PRECIPITATION FORECAST DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 609 PM EST SAT FEB 01 2003 FINAL DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION VALID FEB 03/0000 UTC THRU FEB 05/0000 UTC REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR DAY 1... ...WRN U.S.... MDLS ARE STILL SHOWING SOME DIFFS IN MASS FIELDS OVR THE WRN U.S. AS THE OVERALL PATN BEGINS CHANGING. STG RDGG OVR THE ERN PAC WL SUPPORT DIGGING OF PAC ENERGY INTO INTERIOR SECTIONS OF THE GT BASIN. THE ASOCTD SFC/8H BNDRY CROSSING THE REGION WL HELP FOCUS MSTR AND LIFT...WHILE OVERALL W-SWLY FLOW SUPPORTS UPSLOPE FLOW. MDLS SHOW MOD/STG 8H/7H CNVGNC ALG THE BNDRY WITH ENHANCED CNVGNC IN THE PREFERRED UPSLOPE REGIONS OF THE WASATCH AND CNTRL ROCKIES. SATL PW LOOPS STILL SHOW A CONNECTION INTO THE PAC PLUME OF MSTR...BUT IT IS WEAKENING. NEVER-THE-LESS...THE STG DYNAMICS...OROGRAPHIC LIFT AND FNTL CNVGNC SHLD SUPPORT A BAND OF LGT/MOD PCPN THRU THE REGION WITH POCKETS OF HVY SNOW IN THE HIER ELEVS. ...CNTRL/NRN PLNS... ...18Z UPDATE...THE ETA AND GFS WERE VRY SIMILAR TO THEIR PREVIOUS RUNS ON THE STRENGTH OF THE MLVL TROF. HWVR..THE ETA HAS LOWERED THE SFC PRES ACRS THE RGN..WHICH IN TURN HAS STRENGTHENED THE WAA PATN/MSTR ADVCTN FM THE NRN PLAINS EWD TO THE LOWER GTLKS..RESULTING IN A SGFNT INCREASE IN QPF. EVEN THO THE GFS IS NRLY IDENTICAL TO ITS ERLIER RUN WITH ITS SFC PATN..IT ALSO HAS INCREASED THE PCPN AMTS HERE. SO..HAVE OPTED TO RAISE THE QPF SOME..RESULTING IN A VRY NARROW BAND OF MDT AMTS FM S- CNTRL SD EWD OVR SRN MN TO SWRN WI... MID/UPR LVL MSTR ALG WITH WEAK MLVL ENERGY WL STREAM EWD ALG A WEAK 8H/7H BAROCLINIC ZONE. THIS SHLD SUPPORT A BAND OF LGT TO MDT MIXED PCPN THRU THE REGION. THE MDLS ARE FAIRLY AGREEABLE WITH THE OVERALL ZONE OF PCPN. ...NEW ENG... MDL INCONSISTENCY IN THE ETA AGAIN LEADS TWD THE GFS FCST FOR THIS PD. THE 12 UTC GFS IS VRY CLS TO THE 00UTC RUN...WHILE THE ETA HAS COME INTO MUCH BETTER AGREEMENT WITH THE GFS. THE STG MLVL VORT ALG THE MID ATLC CST THIS MRNG WL CONT TO DEEPEN AND BCM NEG TILTED AS IT LIFTS NEWD TWD THE CANADIAN MARITIMES. THIS WL INDUCE STG CYCLOGENESIS OVR THE WRN ATLC WITH THE SFC LOW LIFTING NEWD AND SPREADING MOD/HVY PCPN OVR MUCH OF ERN NEW ENG. LATEST SATL PW LOOPS SHOW THIS SYS STARTING TO TAP SOME SUB-TRPCL MSTR THAT IS AIMED INTO DOWNEAST ME. WARM AIR ALREADY IN PLC ALG THE CST WL MAKE THIS A DIFFICULT PCPN TYPE FCST FOR THAT AREA. SEE QPFHSD FOR ADTNL HVY SNOW/ICING FCSTS. FOLLOWED THE GFS QPF FCSTS QUITE CLSLY DUE TO ITS RUN-TO-RUN CONSISTENCY. DAY 2... IN THE NORTHWEST... THE ETA IS STICKING TO ITS GUNS AS FAR AS TAKING THE CANADIAN SHORT WAVE SHARPLY SWD ON A TRACK WELL TO THE WEST OF THE GFS. THE GFS HAS BEEN FLIPPING BACK AND FORTH... WITH ITS PREVIOUS 00Z RUN HAVING TAKEN A MORE WESTERN TRACK... BUT ITS LATEST 12Z RUN GOING BACK TO THE EAST. OTHER MODELS SUGGEST A COMPROMISE WOULD BE THE BEST WAY TO GO AT THIS TIME. THEREFORE... HAVE GONE WITH A BLEND ON THE PCPN... WITH LIGHT BUT SIGNIFICANT AMOUNTS IN BOTH THE CASCADES AND THE NRN ID ROCKIES. UPDATE... THE 18Z ETA HAS BACKED OFF ON THE WESTERN TRACK OF THE SHORT WAVE DROPPING SWD FROM CANADA. IT IS NOW CLOSE TO THE COMPROMISE PATH...BETWEEN THE 12Z ETA AND 12Z GFS DESCRIBED ABOVE. THIS GENERALLY SUPPORTS THE ABOVE SCENARIO... BUT HAVE DECREASED WESTERN EXTENT OF LIGHT AMOUNTS IN OR SOMEWHAT. IN THE CENTRAL ROCKIES... THE ETA IS INITIALLY SLOWER THAN THE GFS WITH THE SHORT WAVE SYSTEM MOVING THRU THE SOUTHWEST. THIS IS PROBABLY BETTER FOR THE FIRST HALF OF THE PERIOD... WHEN THE SYSTEM IS MOVING THRU THIS REGION... SINCE THE TREND HAS BEEN SLOWER. EXPECT LOCALLY MDT AMOUNTS IN THE UPSLOPE PORTIONS OF S CENTRAL CO. IN THE MID/LOWER MS VALLEY... THE SHORT WAVE SYSTEM FROM THE SOUTHWEST WILL BE DEVELOPING PCPN HERE DURING THE SECOND HALF OF THE FORECAST PERIOD. THE ETA SYSTEM IS EXPECTED TO CATCH UP WITH THE INITIALLY FASTER GFS DURING THIS PERIOD. HOWEVER... THERE IS QUITE A DIFFERENCE BETWEEN THE TWO MODELS WITH RESPECT TO THE INTENSITY OF THE SYSTEM AND THE AMOUNT OF PCPN. THE STRONG UPSTREAM SHORT WAVE IN THE ETA RESULTS IN A MORE WESTERLY SHEARING 500MB FLOW INTO THIS SYSTEM. THIS KEEPS THE SYSTEM RELATIVELY WEAK... AND PCPN ON THE LIGHT SIDE. THE GFS... ON THE OTHER HAND... IS NOT DIGGING THE NW SYSTEM AS SHARPLY SWD. AS A RESULT... IT HAS A MORE NRLY 500MB FLOW COMING INTO THE WEST SIDE OF THIS SYSTEM... WHICH CAUSES IT TO BE STRONGER THAN IN THE ETA... WITH HEAVIER AMOUNTS OF PCPN. WITH THE OTHER MODELS KIND OF SPLIT ON THE NW SYSTEM... HAVE DECIDED THAT A COMPROMISE IS IN ORDER FOR THIS DOWNSTREAM SYSTEM. THEREFORE... HAVE COMPROMISED WITH THE AMOUNT OF PCPN IN THE LOWER/MID MS VALLEY. IN THE SRN GREAT LAKES... THE MODELS HAVE A WIDE RANGE OF SOLUTIONS REGARDING THE INTENSITY OF A NRN STREAM SFC LOW IN THE REGION. BELIEVE THE SFC DEVELOPMENT SHOULD BE ON THE WEAK SIDE SINCE THE UPPER IMPULSE IS MOVING THRU A CONFLUENCE ZONE. HAVE USED AN ETA/GFS BLEND FOR PCPN AMOUNTS... SOME OF WHICH COULD BE LOCALLY MDT. DAY3... IN THE NORTHWEST... HAVE CONTINUED TO USE A COMPROMISE BETWEEN THE 12Z ETA AND GFS REGARDING THE SHORT WAVE DROPPING SWD THRU THE ROCKIES. DURING THIS PERIOD THE ETA IS FASTER AND STRONGER WITH THIS SYSTEM. RESULTING PCPN PATTERN IN QPF IS A BLEND OF THE TWO PCPN FORECASTS. IN THE EAST... BIG DIFFERENCES IN WHAT IS HAPPENING AT 500MB OVER THE NATIONS MID SECTION BY LATE IN THE PERIOD. THE ETA HAS MORE NRN STREAM TROFFING DROPPING SWD THRU THE GREAT LAKES AND PHASING WITH THE MORE SRN STREAM SHORT WAVE THAT IS CARRYING LOW PRESSURE NEWD FROM THE MS VALLEY TO THE NORTHEAST. THE GFS... ON THE OTHER HAND... IS BRINGING ADDITIONAL SHORT WAVE ENERGY EWD THRU THE SRN STREAM TOWARDS THE MAIN SYSTEM. AMAZINGLY ENOUGH...THE PRIMARY SYSTEM IS FAIRLY SIMILAR IN THE TWO MODELS BY THE END OF THE PERIOD... WITH A DEEP SFC LOW VICINITY OF NRN VT/NH. THE GFS PCPN PATTERN IS A LITTLE SLOWER THAN THE ETA AND FARTHER TO THE NW WITH BEST AMOUNTS. HAVE GENERALLY COMPROMISED BETWEEN THE TWO. MDT TO LOCALLY HVY AMOUNTS ARE EXPECTED FROM THE OH VALLEY NEWD ACROSS MUCH OF THE NORTHEAST. ECKERT/WOLF/LINDNER GRAPHICS AVAILABLE ON THE WEB AT http://www.hpc.ncep.noaa.gov 24HR QP VT 03/00Z 0.01 509647 506639 502634 492626 483621 473617 464615 456617 452618 447623 441626 437627 430628 427628 421631 418632 413637 409644 407646 403648 396650 385658 376666 369675 364686 363691 360695 358701 357709 358720 362732 367742 370747 373750 380754 387755 407746 410748 414752 416758 416764 414768 410773 402781 396784 392787 386791 381796 374804 371811 373814 377814 380813 388810 392810 394817 396824 399835 401846 405855 408865 409873 410882 414894 418908 422919 423933 424952 424965 423975 421983 418993 414003 410013 405022 395039 389057 385060 382063 379065 375065 371064 369065 370075 370083 371092 372097 372106 371111 368115 360116 357119 356125 357130 362139 364143 364149 362157 364162 368163 374158 377157 379159 380162 381169 378178 367178 357180 356183 357188 362189 367193 370197 375202 382209 389213 393216 399218 404215 404207 406199 410189 413185 417183 420184 422183 423177 422171 422166 425162 425156 425150 424147 425140 427135 428131 431128 435124 441123 443125 443129 436140 435148 435156 441160 446162 447166 447171 445179 442184 441188 442192 443195 448192 452192 458185 462182 464178 464175 464170 466169 471168 473167 478166 482165 484161 481155 476151 474146 474145 480142 483140 485134 483129 476127 471128 466132 461132 457130 454127 454123 457118 461114 465113 468112 469109 467101 466095 466085 467069 467053 467036 466008 465976 459950 458941 458931 455911 452891 450882 448872 445866 443859 438848 427827 416806 414802 416799 421796 426793 432789 436787 443785 447783 452782 458779 463776 469771 473767 477760 476753 474748 469744 463743 459743 448744 439740 437737 436731 440729 444730 451732 457731 461728 468725 476720 483716 488711 493706 495703 501692 505684 507680 510670 510661 509647 0.01 514286 512270 516268 518264 518258 508231 495207 491204 486204 480204 476204 471206 458209 449213 443216 440219 440224 443228 447228 455231 454231 448232 443235 442237 442241 448242 452241 460243 468245 475249 479253 481258 485268 487274 491279 495282 498283 504289 507291 510290 514286 0.01 491234 491234 489229 489229 486227 483226 480225 477225 474224 474224 474225 476229 477229 479231 482234 485232 488233 491234 491234 0.25 454006 453994 452982 453969 452956 451943 449931 444908 442896 438883 431863 425847 422844 419844 418847 421859 422865 423873 424884 428909 430921 432933 433946 433956 433004 433028 434034 435038 438047 441053 440057 435057 431049 426043 423044 421047 416052 411056 404060 394074 395079 397081 402081 407082 411086 412091 408092 406095 403103 381119 377123 373126 372129 375137 376138 379134 381131 384129 392124 397124 399129 402129 408125 411124 414126 417128 420128 423127 426124 428120 431117 434115 439113 447113 449107 448101 443096 439093 434094 430088 428085 427080 430076 435075 439076 443077 450083 454083 455076 455069 454063 450056 449052 450047 451039 453018 454006 0.25 501650 498643 494638 488633 483630 475628 469628 462630 454634 448637 440642 432641 427643 419650 417658 410662 404662 401663 399666 398671 400674 403681 398689 395695 394700 395706 394713 390720 384728 382730 383734 385735 390735 398731 405725 415720 422718 434716 443715 450715 456714 464710 482696 490688 494681 497672 500662 501650 0.25 412153 412151 410149 409148 407148 406148 404151 404155 406158 408156 409156 412153 412153 0.25 383196 381195 378195 378195 378196 381198 383196 0.50 422115 417113 412113 411106 409101 406103 404110 400110 394113 391116 391118 397117 403121 408120 414121 419119 422115 0.50 495656 494650 492645 487638 480634 475633 470634 461635 454640 449645 444648 439648 434647 429648 427649 425653 425659 424666 425672 425676 422676 418677 413688 405696 404700 405704 408709 412711 416712 421712 428709 437707 444702 446700 450699 458703 463701 469697 480688 486682 490676 494664 495656 0.50 447953 443929 440914 439908 437902 436896 434902 433911 436926 437939 438963 439978 441988 443995 443002 442011 440023 439029 440036 441040 444039 446034 446027 446016 446003 447990 446982 447957 447953 0.50 447072 447072 444070 441069 441072 441072 444074 447072 447072 0.50 439104 439100 438099 435099 432096 432096 430093 429092 427089 425092 427094 428096 429098 431100 432102 434103 433105 433106 431107 429107 427106 425107 426109 429109 432108 435109 438108 438107 439104 0.50 427064 428060 427056 427056 424053 421055 420056 420060 420064 421066 424066 427064 427064 0.50 414072 412069 412068 410065 407066 404068 406072 407073 410075 412074 414072 1.00 480654 478647 476645 469644 463645 457650 453655 447658 445666 446670 453673 458675 464682 467683 470681 474678 477674 480665 480656 480654 24HR QP VT 04/00Z 0.01 495607 486594 477579 475575 472574 469571 466573 459579 453587 450594 444603 440607 434612 430616 426623 423630 421638 420652 420659 423666 440688 444697 444703 442716 439728 434738 433740 430739 427733 422727 418724 413725 406730 402745 393774 384799 376819 372828 367839 360848 353858 337877 329886 322895 319899 316907 314920 313932 316938 321941 336942 341943 347947 353953 358962 362973 362980 360984 356991 354997 350010 347024 346033 346041 347049 350056 355066 359072 361075 362079 357082 351085 349089 352096 355101 361106 362109 361113 360115 357114 351110 348110 345116 347120 351124 356126 363126 368125 372119 374115 376114 380112 383112 379121 375126 375130 377130 382127 385126 397121 399115 400113 403112 405118 413119 421120 430122 436119 439120 440124 438129 433136 431143 431149 431154 434160 437165 441171 443174 443178 438181 435188 437197 440203 443206 447206 449204 451200 455195 459191 467183 472182 476183 479185 480190 478194 468201 459211 455215 454219 456223 460224 467225 475228 474230 470230 465231 462233 463240 465246 471251 481262 485266 488269 492273 496278 502282 507282 509278 511275 515266 518254 515239 511226 508219 508215 512215 516217 522216 531208 533198 535186 535179 533173 529165 526159 521153 500129 491118 485103 484099 481094 472086 468083 465076 463070 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450664 464684 471691 479695 487695 495693 505689 509687 514681 515675 514669 512661 510652 509648 0.25 476163 478159 478155 476150 473145 468142 462