000
FXUS04 KWBC 130810
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
409 AM EDT MON MAY 13 2013


PRELIM DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID MAY 13/1200 UTC THRU MAY 16/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR

DAY 1

PACIFIC NORTHWEST INTO THE NORTHERN ROCKIES

THERE ARE NO SIGNIFICANT MODEL DIFFERENCES WITH THE AREA OF STRONG
NORTHEASTERN PACIFIC HEIGHT FALLS FORECAST TO PUSH INLAND INTO THE
PACIFIC NORTHWEST MONDAY---ACROSS THE NORTHERN ROCKIES MONDAY
NIGHT AND INTO THE NORTHERN HIGH PLAINS BY EARLY MONDAY.  ABOVE
AVERAGE PW VALUES--2+ STANDARD DEVIATIONS ABOVE THE MEAN---ALONG
THE ASSOCIATED FRONTAL BOUNDARY WILL SUPPORT MODERATE TO LOCALLY
HEAVY PRECIPITATION AMOUNTS IN THE FAVORED TERRAIN REGIONS FROM
FAR NORTHWESTERN MT---NORTHERN ID---AND THROUGH THE WA
CASCADES--COAST RANGE AND OLYMPIC RANGE.  THE HIGHER RESOLUTION
NAM AND SREF MEAN WERE USED FOR QPF DETAILS ACROSS THESE AREAS DAY
1

NORTHERN PLAINS

TO THE EAST OF THE NORTHWESTERN TERRAIN ACROSS THE NORTHERN
PLAINS---LOW LEVEL CONVERGENCE EXPECTED TO STRENGTHEN AHEAD OF THE
STRONG HEIGHT FALLS MOVING OUT OF THE NORTHERN ROCKIES MONDAY
NIGHT. THE ASSOCIATED STRENGTHENING ISENTROPIC LIFT WILL SUPPORT
INCREASING CONVECTIVE
POTENTIAL MONDAY NIGHT INTO EARLY TUE IN THE AXIS OF ABOVE AVERAGE
PW VALUES WHICH WILL ACCOMPANY THESE HEIGHT FALLS ACROSS THE
NORTHERN PLAINS.  AT THE MOMENT---IT APPEARS THAT ANY CONVECTION
THAT DEVELOPS MAY BE VERY FAST MOVING TO THE EAST--LIMITING QPF
AMOUNTS.  THE HI RES ARW AND THE NAM CONEST ARE ON THE HEAVIER
SIDE OF THE QPF SPREAD---DEPICTING .50-1" AMOUNTS OVER
NORTHEASTERN MT INTO FAR NORTHWESTERN ND.  GIVEN THE POTENTIAL
FAST MOVEMENT---DAY 1 QPF LEANED TOWARD THE SOMEWHAT LIGHTER SREF
MEAN---DEPICTING .10-.25"+ AREAL AVERAGE AMOUNTS.

NORTHEASTERN MEXICO INTO FAR SOUTHERN TX

LATEST MODEL CONSENSUS IS FOR PRECIPITATION ASSOCIATED WITH THE
PERSISTENT UPPER LOW OVER NORTHWESTERN MEXICO TO REMAIN MOSTLY
OVER NORTHEASTERN PORTIONS OF MEXICO DAY 1---POSSIBLY SKIRTING THE
BORDER AREAS ALONG THE RIO GRANDE.  CONFIDENCE REMAINS LOW WITH
PRECIPITATION TO THE EAST AND NORTHEAST OF THIS UPPER LOW--WITH
THE DAY 1 QPF NOT DEVIATING FROM THE ABOVE MODEL CONSENSUS.


ELSEWHERE---LIGHT OVERRUNNING PRECIPITATION AMOUNTS MAY SPREAD
INTO THE UPPER MS VALLEY/UPPER LAKES REGION MONDAY TO THE EAST OF
A WELL DEFINED WARM FRONT.  LIGHT DIURNAL SHOWER ACTIVITY ALSO
POSSIBLE UNDERNEATH THE COLD UPPER TROF AXIS SWINGING EASTWARD
MONDAY FROM THE EASTERN LAKES---THRU THE CENTRAL
APPALACHIANS---MID ATLANTIC AND NORTHEAST.

DAYS 2 AND 3...

...PACIFIC NORTHWEST...

NEUTRAL TO WEAKLY CYCLONIC MID/UPPER LEVEL FLOW WILL PREVAIL
ACROSS THE REGION THROUGH THURSDAY...PROVIDING PERIODIC PASSAGES
OF MAINLY WEAK SHORTWAVE TROUGHS AND BRIEF SURGES OF ONSHORE FLOW.
 THE MODELS DEPICT MODEST SPREAD WITH THE QPF DETAILS...MOSTLY IN
RESPONSE TO TIMING/STRENGTH DIFFERENCES OF THE FAST LOW AMPLITUDE
FLOW THAT THE MODELS ARE HAVE DIFFICULTY RESOLVING.
THEREFORE...THE FORECAST APPROACH EMPHASIZES THE MODEL
CONSENSUS...USING THE HIGHER-RESOLVING GUIDANCE WHERE
APPLICABLE...PARTICULARLY ALONG TERRAIN GRADIENTS...AND DENOTES
THE INFLUENCE FROM 3 SHORTWAVE TROUGHS...ONE WEDNESDAY...ANOTHER
WEDNESDAY NIGHT...AND A THIRD ON THURSDAY.

...ROCKIES...

UPSLOPE FLOW ORIGINATING FROM THE WEST ACROSS THE
BITTERROOTS...AND POST-FRONTAL EASTERLY FLOW ACROSS THE TETONS/BIG
HORNS/BLACK HILLS/COLORADO ROCKIES...WILL AID DIFFERENTIAL HEATING
TO PROMOTE MAINLY SCATTERED LATE AFTERNOON/EARLY EVENING
CONVECTION TUESDAY AND WEDNESDAY.  EVEN THE HIGHER RESOLVING
GUIDANCE MAY NOT BE ADEQUATELY RESOLVING THE FINE-SCALE WIND
STRUCTURE.  THUS...
RELIED MORE UPON CLIMATOLOGY RATHER THAN ACTUAL MODEL QPF TO
DERIVE THE MOSTLY LOW PRECIPITATION TOTALS.

...GREAT LAKES/NORTHEAST/NEW ENGLAND/MID-ATLANTIC/OHIO VALLEY...

MOSTLY NARROW AND QUICK-MOVING BANDS OF RAIN WILL ACCOMPANY THE
INFLUENCE OF A VIGOROUS BUT INITIALLY MOISTURE-STARVED SHORTWAVE
TROUGH MOVING ACROSS SOUTHERN CANADA THROUGH 00Z THURSDAY...WITH
MOST OF THE RAIN ASSOCIATED WITH A BROAD WARM-CONVEYOR BELT...WITH
ADDITIONAL BUT GENERALLY LESS WIDESPREAD RAIN ACCOMPANYING A COLD
FRONTAL PASSAGE.  RELATIVELY NARROW BUT STILL CONSIDERABLE
SOLUTION SPREAD CONTINUES WITHIN THE GUIDANCE...SUGGESTING A MODEL
CONSENSUS AS THE MOST PRUDENT APPROACH.  ONE EXCEPTION
HOWEVER...WAS TO DISCOUNT SOME OF THE HIGHER AMOUNTS OF THE GFS
GENERATED OVER THE UPPER GREAT LAKES...WHICH MAY BE ATTRIBUTED TO
AGGRESSIVE EVAPOTRANSPIRATION NOT SUPPORTED...AT LEAST AS
AGGGRESSIVELY...BY THE NAM AND ECMWF.  BY EARLY THURSDAY
THOUGH...MOISTURE ORIGINATING FROM THE WESTERN GULF OF MEXICO
SHOULD BEGIN TO POOL SUFFICIENTLY ALONG THE SLOWING OR STALLING
FRONTAL BOUNDARY ACROSS THE OHIO VALLEY TO SUPPORT HIGHER TOTALS
EASTWARD TOWARD THE MID-ATLANTIC REGION.  CONFIDENCE IN THE
PRECISE DETAILS IS LOW DUE TO TIMING UNCERTAINTIES WITH THE UPPER
LOW PRESENTLY OVER MEXICO...AND THAT SOME IF NOT THE MAJORITY OF
MOISTURE POOLING ALONG THE FRONT WILL BE HIGHER-BASED...WHICH WILL
BE DIFFICULT FOR THE MODELS TO ADEQUATELY RESOLVE AND PREDICT THE
BEHAVIOR OF.

...SOUTHERN PLAINS/SOUTHERN MISSISSIPPI VALLEY...

MOISTURE WILL STEADILY INCREASE AND DEEPEN THROUGH THE PERIOD IN
ASSOCIATION WITH THE PROLONGED FETCH ORIGINATING OVER THE GULF OF
MEXICO...ALONG WITH SLOWLY INCREASING ASCENT AND FAVORABLE
THERMODYNAMIC PROFILES FOR RAINFALL CREATED BY THE SLOW APPROACH
OF THE UPPER LOW OVER MEXICO.  TIMING AND STRENGTH DIFFERENCES
WITH THE LOW REMAIN APPRECIABLE...WITH THE SLOWER/STRONGER ECMWF
CONSIDERED SUSPECT DUE TO POSSIBLE CONVECTIVE GRID-SCALE FEEDBACK.
 THUS...INCORPORATED ONLY PORTIONS OF ITS SOLUTION ALONG WITH THE
NAM/GFS/UKMET...WHICH WERE FASTER AND WEAKER.  CONFIDENCE IS QUITE
LOW ACROSS THIS REGION DUE TO THE MODEL SPREAD AND MESOSCALE
UNCERTAINTIES THAT ARE DIFFICULT FOR THE MODELS TO RESOLVE.

ORAVEC/JAMES

GRAPHICS AVAILABLE ON THE WEB AT WWW.WPC.NCEP.NOAA.GOV

24HR QP VT 14/12Z
 0.01 536211 537204 537197 536188 529168 519155 512150 506145
      501141 496136 487126 486123 487117 488110 490104 492102
      498095 499092 501093 502095 505106 507110 511113 516120
      520123 524123 527122 529120 532108 533092 534067 533041
      531032 527024 521017 516013 513006 511001 510995 508980
      506976 505968 502961 506957 509954 510950 514947 517940
      516935 512934 509931 505930 499929 491931 489928 491925
      494918 495911 492906 486886 474877 472872 474868 475864
      474859 470855 466855 463854 451850 448851 445849 439851
      437856 432862 434870 434874 437877 442880 446888 455886
      461890 473898 474899 472902 467904 460903 453904 449906
      448908 444916 445925 451927 450931 450935 453942 455948
      458956 461959 464959 482960 484962 482965 473965 471963
      467964 462965 457967 457976 458987 462004 463009 465012
      469020 472027 473034 474045 474051 473055 471069 468071
      463072 457075 456078 455085 455097 450105 444119 442126
      442134 450137 451139 451144 442153 443158 445162 443172
      436191 436197 437199 439203 443205 450201 455197 457193
      459193 463193 466196 470198 472201 471203 464205 458209
      452212 446213 442213 439214 436216 435220 438228 443230
      447228 453230 449232 442235 439238 438243 441248 451252
      465256 471258 474261 481266 485271 488274 489277 496282
      498286 504290 508290 511287 516279 519269 520265 520259
      520253 519246 518238 515230 512223 508217 507211 511211
      515213 517216 524231 527233 530227 532224 535213 536211
 0.01 458717 456709 451708 447708 442710 441710 443718 440723
      437727 441728 445729 448728 454725 455721 458717
 0.01 448746 447742 446739 442737 438737 434742 433747 432752
      433759 433765 436769 438764 439759 441754 446749 448746
 0.01 436776 435772 434772 433773 434777 435778 436776
 0.01 395798 392792 388781 385771 379769 375775 373781 371790
      372794 374798 375803 376811 378814 381814 387814 390812
      392809 395806 395802 395798
 0.01 410072 410060 403059 401056 395049 392046 389046 387050
      389053 392057 391061 389063 386065 384067 380067 375068
      372068 375072 375079 378080 381083 384083 387080 390080
      393080 395083 401080 404077 407076 410072
 0.01 229020 237028 240031 244036 249048 252060 260068 264070
      268075 285088 289089 291091 294091 296088 297078 292066
      291050 291031 290024 287021 281016 279010 275007 270004
      270995 269992 266990 263985 262978 260972 256967 254961
      251957 247956 245958 242958 232957
 0.25 527193 526187 525178 523172 521168 507151 498145 495142
      492138 489134 483130 480128 475126 472126 471128 470137
      475140 480141 483143 484148 483151 479152 474150 467142
      462142 459144 453156 453159 455163 458165 461164 464166
      474172 481178 488184 497192 508195 514197 520199 524197
      527193
 0.25 514266 516258 515252 512242 509231 505222 501212 495204
      489204 486205 481205 477207 471212 464215 461217 455218
      454219 455223 463229 465239 470246 478252 484259 489266
      495275 501281 507283 509280 512269 514266
 0.25 522096 523091 522087 522082 522077 521072 521068 520065
      519063 517060 514060 512063 512068 512072 512077 512082
      513086 514091 514092 515096 517099 520100 522096
 0.25 498246 495244 493238 491233 489228 483226 477224 474224
      477227 480230 482236 485235 491237 493241 495245 498246
 0.25 503040 504035 503031 501027 500018 498012 495006 489006
      487011 485015 485019 484027 484033 484041 485048 488051
      491053 493050 495045 497043 499043 503040
 0.25 264026 263023 262021 260023 260025 260026 260027 263027
      264026
 0.25 262011 258004 253997 251994 251988 252985 252979 251973
      248971 244970 242972 239981 239987 239993 241004 241010
      243013 246017 251017 260014 262011
 0.50 511255 509240 507235 504229 501219 499213 497210 494208
      483208 475211 472215 467218 469221 472220 475219 487223
      490226 492230 499241 501245 503251 506257 508259 511255
 0.50 503276 504266 502260 499258 494251 491248 489244 481241
      479234 477231 475231 473232 471235 471239 472241 476246
      478248 485254 489261 494268 499274 503276
 0.50 507174 507170 505166 499162 491158 482157 473158 470149
      466146 462148 463155 464158 473159 478166 484171 490175
      498179 505178 507174
 0.50 484134 483134 481132 478131 475133 477137 480138 483138
      484134
 1.00 492216 491215 488214 485213 482213 481213 482214 485215
      487216 490217 492216
 1.00 478239 478238 476235 474237 475239 478239 478239

24HR QP VT 15/12Z
 0.01 566908 566900 565893 564880 558855 553839 546828 537816
      533810 529807 512796 500791 495790 489792 468793 461794
      456794 446792 434791 426786 405780 401778 395780 389784
      385787 385791 385795 386799 395804 398808 403812 412818
      417838 416845 418854 415868 415875 412881 410894 408907
      408914 407919 407928 406931 406935 407945 411949 413945
      417942 421944 428942 430946 428949 425953 424956 421958
      418963 416966 413968 413975 418983 421983 422980 429977
      438968 441977 446982 448986 458980 462976 468975 482973
      487975 490982 490993 489001 489006 492009 496012 496029
      497050 499067 499079 497086 495108 495118 495129 494134
      492137 486138 483142 482151 484160 486167 486174 489175
      490180 491189 493194 501189 503187 505188 508191 513198
      512208 517211 524214 526215 528213 533209 537202 538191
      536185 530172 527166 524159 520142 519137 519132 522125
      530092 532087 533083 533077 535073 537051 541013 543005
      543992 544984 547977 549960 550955 552955 553955 557948
      560942 563937 564932 566916 566908
 0.01 521260 522250 520242 519234 516229 514223 510218 509215
      506213 503209 496207 490205 487203 483203 480207 475208
      471211 467213 465217 465221 475227 467231 462235 459239
      461246 458249 454256 452262 451267 451272 454274 460277
      465276 468277 472277 477279 483292 486298 489299 490303
      493309 497311 501311 505306 508301 511294 514286 516277
      519263 521260
 0.01 418053 413037 415029 415018 414006 413002 410999 406996
      398996 395997 394002 393005 392009 392015 391020 391028
      386035 382039 378041 374041 369040 360049 356050 352051
      344051 335051 333054 330055 330059 334065 341079 341089
      341092 344093 346096 347095 352090 358076 362071 366069
      369072 375076 378075 379069 381065 387063 404062 411061
      414059 418053
 0.01 372964 373960 371957 367957 361959 358961 347964 341965
      338965 335964 325964 316963 309964 306966 302969 299972
      296975 292972 285968 276965 268962 260959 252958 248959
      243963 240969 237978 237983 239986 242998 247004 259015
      265020 270023 273026 287034 293035 296037 302037 305036
      317033 328032 332031 335027 340024 341021 340014 337011
      330004 321001 319999 322997 327996 339994 342992 348989
      357984 360981 362980 372964
 0.25 558895 557885 556880 551866 545856 539847 534839 527833
      520823 514816 507811 499809 495810 492813 489818 488822
      489838 487843 485844 483845 483852 485859 487860 489859
      490863 489870 494880 497885 496889 494900 500958 501972
      504984 508997 509005 510012 510018 513025 518034 521036
      525033 529024 533009 535996 537981 538969 538958 540953
      545945 549941 551935 555923 558908 558895
 0.25 523192 522187 521185 518182 517181 515179 512177 510175
      510174 507174 510176 510180 512181 514185 515186 517189
      519191 520192 523193 523192
 0.25 514257 513247 509236 504229 502228 499227 496236 498244
      499247 495245 490242 485246 488254 492262 496268 498272
      503274 505273 506270 507263 508259 511258 514257
 0.50 554908 553895 551885 545875 528858 525852 523845 517843
      514844 511849 509855 510866 508871 507889 508899 510909
      511925 512936 512956 512964 513973 515980 519985 523988
      526989 529986 531979 532972 532960 533955 545931 549924
      551917 554908
 0.50 498260 497256 496254 494252 491252 491253 493257 494258
      496261 498260
 1.00 543907 541897 540893 534892 531894 529897 527903 526908
      526918 525923 524933 526937 528941 532936 534930 536924
      539918 542912 543907

24HR QP VT 16/12Z
 0.01 547795 542787 540784 538778 531750 528730 526725 524718
      524710 522703 520701 517698 516694 513688 511683 508680
      503669 497660 494656 490654 476648 469644 464642 457640
      450641 439643 437642 433644 427643 421647 412654 406656
      398661 391668 388672 384676 372692 368696 367698 365706
      362713 359720 358726 358735 358744 364752 366754 366758
      368768 369776 375799 377806 378812 378824 377859 376866
      374872 369885 367891 365894 361897 348905 333915 326920
      323922 319926 316932 314935 311937 306939 300944 293948
      291952 289957 290965 293970 297974 302979 309982 314981
      317983 326982 334979 345977 351974 357970 367960 371955
      375953 379955 381961 384969 385971 387977 383984 378991
      377993 372996 368003 358005 336007 324002 316003 317009
      320013 323015 325016 332015 336015 340017 354016 374014
      376011 379010 382006 384006 387002 390998 389995 393990
      398990 406989 406980 404968 404963 404956 406938 407932
      407923 414841 416840 419841 423846 426848 432841 435834
      438831 440827 447823 450818 454816 459815 465816 473818
      478821 483822 486824 492829 499837 502841 502848 500857
      498861 499866 504873 505876 508883 510894 514899 523909
      534920 545906 550897 557886 559881 560876 557858 555840
      553832 551825 548805 547795
 0.01 537201 534190 528179 525174 522172 519167 514164 505157
      500154 495158 492162 490179 491185 494189 499192 505195
      510196 513199 521208 526211 533211 537201
 0.01 520259 521254 520248 519238 514227 512222 511220 508218
      506214 502211 498204 491202 480203 468209 464211 461214
      457219 456223 454226 452223 450220 449216 445215 438215
      428216 423217 421219 416224 409230 405230 400227 398226
      396227 395233 396236 398239 403242 409241 412242 415241
      416243 419246 423247 425246 431241 434235 437230 444228
      449224 452223 453228 449233 448237 445241 453254 455257
      460261 466261 469259 479262 483268 498283 500287 502289
      507289 512283 516273 518264 520259
 0.01 463178 462170 459163 458160 454156 452152 451150 451146
      454143 454139 455134 457131 458120 458106 459100 460093
      459089 458088 453084 447091 431092 427091 426094 421101
      412102 408097 406094 406098 406110 411111 415112 417115
      420119 422120 425123 428124 432117 436115 441115 443118
      445122 445125 443129 440136 436139 434145 435151 438158
      443163 445170 446175 445178 442183 438185 436192 438198
      441202 444205 446202 448196 463178
 0.01 465047 465039 464030 464026 462017 460013 457009 454006
      451005 448002 446002 442999 437999 434004 433007 431012
      432025 438032 444040 450052 452055 456055 458053 462051
      465047
 0.01 436056 435051 432047 422041 420035 417032 410032 403034
      394037 391037 389035 383034 380032 374032 369033 363035
      357041 353045 351051 349053 346054 341054 338058 341059
      353059 357063 361066 367066 370069 372076 375080 378083
      384083 388080 395080 401080 404076 412069 418062 433061
      436056
 0.01 301017 301014 298012 296010 292010 284011 280011 275010
      270010 266009 264007 261002 255998 251995 245992 240990
      237989 235990 234998 235003 237006 240011 246014 250018
      257019 268023 284023 292022 298021 301017
 0.25 546838 544825 542817 537808 533798 528775 524763 521754
      516747 511744 506740 500734 491726 485721 483721 479722
      479732 477737 477746 476752 473756 470759 471763 473767
      472773 471780 473786 475791 477794 481797 492804 498808
      502812 512826 516832 518837 519842 517853 517860 519867
      520873 522878 525883 530887 534886 539884 543878 546871
      547861 547848 546838
 0.25 507273 506268 505260 503256 500251 495245 493243 487242
      485245 487251 489256 493262 495266 497270 502275 507273
 0.25 419781 416775 411771 407767 400763 395762 392759 383762
      383766 385771 384803 386818 386833 385849 384865 382880
      379896 379903 381907 386907 390906 395900 397894 398887
      400870 403839 405825 409811 411804 414799 416791 418783
      419781
 0.25 393705 390704 388704 387705 386706 385707 383710 381713
      380714 379716 378719 380719 383718 385716 388714 390711
      392708 393705
 0.25 363933 364930 362927 358925 350926 340928 331934 329936
      326941 325951 323955 325962 328962 334961 342956 347950
      350947 355943 361937 363933
 0.50 522795 518787 516783 513781 507776 501774 496771 494773
      493779 498787 502793 508799 510803 513806 516808 518807
      520806 523800 522795
 0.50 500261 499258 497255 497254 496254 496257 496259 498263
      500261
 0.50 398828 396825 393826 391827 391831 391839 389847 389855
      388866 388875 388880 391882 394877 395868 396860 397852
      397842 398832 398828

$$