Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 070658
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
157 AM EST WED DEC 07 2016


PRELIM DAY 1 QPF DISCUSSION
VALID DEC 07/1200 UTC THRU DEC 08/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...NORTHERN CALIFORNIA/SOUTHERN OREGON...

WARM AIR ADVECTION WILL INCREASE ACROSS NORTHERN CALIFORNIA TODAY
OUT AHEAD OF AN AREA OF SURFACE LOW PRESSURE MOVING INTO THE
NORTHEAST PACIFIC. WILL HAVE A DECENT PLUME OF MOISTURE ASSOCIATED
WITH THIS SYSTEM...WITH PRECIPITABLE WATER VALUES FORECAST TO
INCREASE TO AROUND 1-1.5 STANDARD DEVIATIONS ABOVE NORMAL...WITH
ANOMALOUS LOW LEVEL MOISTURE TRANSPORT PRESENT AS WELL AIDING IN
UPSLOPE PRECIPITATION EFFICIENCY. HOWEVER NEITHER OF THESE
ANOMALIES ARE ALL THAT IMPRESSIVE...AND OVERALL SYNOPTIC SUPPORT
FOR ASCENT IS NOT GREAT. THUS GENERALLY THINK WE WILL JUST SEE A
LONGER DURATION AREA OF STEADY LIGHT TO AT TIMES MODERATE RAINFALL
IN THE BROAD WARM AIR ADVECTION REGIME. THE LACK OF A STRONG
SHORTWAVE OR UPPER JET ALONG WITH THE LACK OF INSTABILITY IS
EXPECTED TO GENERALLY KEEP HOURLY RAINFALL RATES AT OR BELOW
0.25"...WHICH SHOULD MINIMIZE ANY FLOODING THREAT.

THERE WERE SOME MODEL DIFFERENCES WITH REGARDS TO THE WHERE
EXACTLY PRECIPITATION AMOUNTS WOULD BE MAXIMIZED...WITH THE 0Z NAM
AND 12Z ECMWF NORTH OF THE 0Z GFS/UKMET. THE TREND AMONGST THE
GUIDANCE HAS GENERALLY BEEN FOR A FURTHER SOUTH QPF FOCUS...AND
THIS TREND APPEARS TO HAVE SUPPORT FROM RECENT SATELLITE IMAGERY.
THUS WPC QPF GENERALLY FOLLOWED A BLEND OF THE 0Z GFS/UKMET AND
THE 0Z HIGH RES ARW...ALL THREE OF WHICH FAVORED A FURTHER SOUTH
QPF AXIS. THIS INCREASED AMOUNTS SOME ACROSS PORTIONS OF NORTHERN
CALIFORNIA (0.75-1.5" ACROSS THE FAVORED TERRAIN) AND DECREASED
AMOUNTS OVER SOUTHERN OREGON.

...SOUTH FLORIDA...

THE COLD FRONT THAT HAD BEEN PUSHING THROUGH THE EAST COAST HAS
STALLED OVER SOUTH FLORIDA.  A NARROW AXIS OF ABOVE AVERAGE
PRECIPITABLE WATER VALUES ALONG AND AHEAD OF THIS FRONT WILL
SUPPORT CONTINUED ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS SOUTH FLORIDA THROUGH TODAY. THE LACK OF A FORCING
MECHANISM SHOULD GENERALLY KEEP CONVECTION MORE SCATTERED IN
NATURE...HOWEVER LOCALLY HEAVY RAINFALL AMOUNTS ARE POSSIBLE WHERE
STORMS DO FORM. GENERALLY FOLLOWED A HIGH RES BLEND FOR QPF...WITH
ISOLATED 1-3" AMOUNTS POSSIBLE GIVEN THE SLOW STORM MOTION AND
HIGH PWAT AIR.

...NORTHERN PLAINS INTO THE UPPER LAKES AND NORTHERN NEW ENGLAND...

THE SURFACE LOW PRESSURE THAT HAD BEEN BRINGING SNOW AND WIND TO
THE NORTHERN PLAINS WILL CONTINUE TO PROGRESS EASTWARD ACROSS
SOUTHERN CANADA TODAY. IN ITS WAKE ONLY EXPECTING GENERALLY LIGHT
QPF AMOUNTS OVER NORTHERN ND AND MN. AS LOW LEVEL FLOW TURNS MORE
WEST TO NORTHWESTERLY WILL SEE CONTINUED COLD AIR ADVECTION ALOFT
AND AN INCREASING LAKE EFFECT SNOW POTENTIAL. THE GREATEST FOCUS
WILL BE ACROSS NORTHERN MI...HOWEVER SOME LIGHTER AMOUNTS ARE
LIKELY OFF OF LAKE ERIE AND ONTARIO AS WELL. WPC QPF RELIED
HEAVILY ON A BLEND OF THE HIGH RES GUIDANCE (ARW/NMMB/NSSL WRF)
ACROSS THIS REGION TO BETTER CAPTURE LAKE EFFECT AND TERRAIN
DETAILS.

...SOUTH TEXAS...

SHOULD SEE SOME SHOWER ACTIVITY TONIGHT BECOME FOCUSED NEAR THE
TEXAS COAST AS THE SHORTWAVE PASSING TO THE NORTH PUSHES A COLD
FRONT SOUTH ENHANCING LOW LEVEL CONVERGENCE. OVERALL A PRETTY WEAK
SYSTEM...WITH LIMITED MOISTURE AND NO INSTABILITY. THUS RAINFALL
SHOULD BE PRETTY LIGHT...AND GENERALLY FOLLOWED A BLEND OF THE
AVAILABLE HIGH RES GUIDANCE FOR QPF ACROSS THIS REGION. THIS KEEPS
AREAL AVERAGED AMOUNTS BELOW 0.25"...ALTHOUGH COULD LOCALLY SEE
AMOUNTS GET AS HIGH AS 0.75".

GRAPHICS AVAILABLE ON THE WEB AT
WWW.WPC.NCEP.NOAA.GOV/QPF/QPF2.SHTML

CHENARD

24HR QP VT 08/12Z
 0.01 553908 553886 551878 550867 548854 547852 547846 546841
      545838 544828 543825 542820 541810 541802 541790 541782
      539771 538765 536762 535749 534747 533741 532731 529723
      526716 520704 514690 505680 500676 493674 483673 481672
      477673 476666 473648 469645 460648 455652 448655 443658
      440663 436669 433672 428671 422671 419669 417665 414659
      411654 401648 396646 390647 381650 377655 373660 372664
      372669 377681 384715 391726 396728 399729 402726 406721
      410718 413710 416708 419708 424712 425717 425721 423727
      424735 429749 431756 434764 457771 445796 436806 433811
      432816 438819 441821 444819 449816 452816 454818 455824
      455832 454836 452839 448846 439852 432854 429853 429850
      429844 429840 425843 420847 419850 418854 418858 417861
      421863 432866 441866 447864 454862 458860 459864 460874
      458881 454897 446908 450918 446923 442927 438932 438935
      441935 448935 451935 454933 460932 460945 460949 459954
      455957 456961 455966 454974 450979 454981 458980 463984
      471991 473998 477004 478007 482007 483006 485000 486997
      487000 487006 488011 490013 493014 498011 503011 506014
      508016 510017 515016 520012 528004 531000 534993 536987
      539977 547941 551924 553908
 0.01 486892 482890 479892 476900 473907 469915 465921 460927
      463930 465928 467925 470919 474912 479905 482899 486892
 0.01 424302 425295 425290 421281 419276 422273 425271 426267
      427265 430263 432256 435244 439214 438209 436206 431197
      429192 427187 422179 418172 413164 409156 401150 394144
      389143 388148 390153 390157 389160 386170 386180 382183
      377182 366181 362182 360183 360185 364193 365199 363204
      361208 359210 356211 352211 351217 351223 351229 351235
      353238 356243 357248 356255 357259 357264 358269 361272
      362277 366287 369290 373292 382297 392301 402305 407305
      412305 419304 424302
 0.01 434097 433096 431094 429094 428094 426093 424093 422093
      424096 426096 427098 427099 429099 431099 432099 434097
      434097
 0.01 431785 431782 430781 425782 424785 423790 422796 420800
      419806 419811 421809 423806 425801 427797 429793 431788
      431785
 0.01 422053 420032 413015 404977 403972 402967 399959 396956
      396961 396972 393981 390990 387998 381005 379008 379013
      383019 388027 393032 394038 393044 390047 387045 383047
      379047 377048 375047 372046 376051 382051 384054 386054
      389049 392050 394054 393059 391061 390068 391070 394069
      396067 398068 397073 398082 399086 400088 400081 402074
      404071 408071 411069 413065 414064 411059 409055 408050
      410048 411050 414052 416055 419055 422053
 0.01 413129 413127 412126 412124 411123 411122 409120 409119
      408118 406117 404117 403118 403121 404123 403125 404126
      405127 407128 409128 410129 412130 413129
 0.01 412094 412092 410091 409091 408091 408093 410094 412094
      412094
 0.01 407065 407063 407061 405058 404058 402058 401060 400062
      400065 401066 403066 405066 407065
 0.01 386940 386931 382929 380924 366929 362931 356931 347932
      337932 332932 331930 332928 332919 335910 334903 332903
      330906 322919 318927 314920 310913 310908 308904 308898
      306894 305891 302888 293888 289890 287895 286912 286922
      286928 285933 284938 283941 281945 277947 259943 250943
      245947 241952 236959 233964 231968 231973 231977 233980
      235983 238987 247998 253002 258008 263013 266015 269015
      271012 271007 278003 284997 285993 286989 293973 301962
      306957 311957 312962 311988 311010 310016 309020 306028
      304032 303039 303050 303059 308058 314052 316050 318044
      319035 318026 319003 319991 321987 321982 321971 323967
      325965 328966 336967 339967 339962 340960 343959 346961
      351961 357961 366961 373959 377956 381950 383944 386940
 0.01 370052 368052 367052 365052 363052 361051 361052 359053
      359054 357056 357058 359058 361059 361058 363056 365055
      366055 368055 369054 370053 370052
 0.01 356084 356082 354082 352081 350081 348081 348083 348086
      348088 349090 351093 352090 353088 354086 355085 356084
 0.01 270796 270789 267785 266779 262780 255786 251788 248792
      245795 244801 245804 245809 240817 237826 231844 230849
      230855 234864 237866 241865 245856 249848 255847 258844
      261835 264825 261814 261808 263803 267799 270796
 0.25 533830 533813 532805 529801 526798 524793 522788 519782
      516787 515794 511804 510818 509831 506843 505850 505857
      504865 505873 506890 506899 506906 508912 511913 524901
      528890 530878 532863 532848 533830
 0.25 501983 501980 500978 500977 499977 497976 495976 494976
      492977 493980 494982 495984 497984 499984 500983 501983
 0.25 488947 489944 489942 487941 486942 486944 487947 488947
 0.25 486856 486846 484837 483835 479835 472837 468841 469851
      471858 475860 475867 473873 471872 470875 468883 467890
      465897 465900 467902 470902 472900 476887 479880 480872
      482865 485859 486856
 0.25 468809 466807 464809 462812 460817 459822 459830 459835
      459838 461838 462834 464829 465824 466817 467811 468809
 0.25 456791 456788 455786 454787 452789 452790 452792 452794
      453794 454796 456793 456791
 0.25 458844 458842 457842 456843 454844 453845 451846 450848
      450850 451852 452852 453852 455852 456850 457849 457847
      458845 458844
 0.25 419238 414215 409203 406199 398198 393198 387197 378190
      367186 364187 369191 372202 374207 372213 366222 364225
      364229 365236 365249 365257 366263 367269 370273 374278
      379281 392285 398287 402282 409274 412270 415262 416254
      415247 419238
 0.25 260805 260803 260801 260799 260797 260795 259793 258793
      256791 254792 253793 253794 251796 251798 250800 251802
      251804 252805 253806 254807 254808 256809 258809 260807
      260805
 0.25 263964 265960 263957 259956 256958 254958 252960 251964
      252966 253970 255972 257972 259970 261968 262966 263964
 0.25 251832 251830 251829 250830 249832 249833 249835 249837
      250837 250834 251832 251832
 0.50 479845 478843 477842 476841 474842 473842 472843 471844
      471845 471847 472848 473849 475849 476848 477847 478846
      479845
 0.50 478875 478872 477871 477872 476875 478875 478875
 0.50 476880 477877 476875 475877 474879 474880 473881 471882
      471883 470885 471888 471889 473887 474885 475884 476882
      476880 476880
 0.50 463822 464819 463817 462819 461822 461824 462826 462824
      463823 463822
 0.50 414238 411227 407223 404221 402223 399223 397222 397219
      402218 404216 403213 401209 397205 393201 387198 383195
      377192 375193 375197 378202 384211 383216 378219 374221
      370219 370231 370245 370259 372265 374270 378275 383277
      390279 396280 399279 404273 406267 406262 407256 408253
      406250 407246 410242 414238
 0.50 258805 259803 258801 258799 257797 257796 255795 253797
      253798 253800 253802 254804 255805 256806 258806 258805
 1.00 406234 404232 404231 403230 401228 399227 398227 396227
      394228 395231 397232 399233 400234 401235 402235 403236
      405236 405235 406234
 1.00 398269 395261 393254 389248 384243 381236 378233 374234
      376242 379249 379259 378264 380267 386271 394272 398269
 1.00 388231 389229 389227 389226 387225 386226 386228 386229
      388231 388231
 1.00 387201 386200 384200 383200 384200 385201 387201 387201
 1.00 381232 382230 383227 382226 380225 378226 378228 378231
      379232 380233 381232

$$





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