Quantitative Precipitation Forecast
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

000
FXUS04 KWBC 210723
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
322 AM EDT TUE MAR 21 2017


PRELIM DAY 1 QPF DISCUSSION
VALID MAR 21/1200 UTC THRU MAR 22/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...WESTERN U.S....

THE FULL LATITUDE TROUGH OFF THE WEST COAST WILL AGAIN BECOME
REINFORCED FROM BOTH NORTHERN AND SOUTHERN STREAM COMPONENTS
UPSTREAM -- THIS AS THE INITIAL CYCLONE OFF THE PAC NW BECOMES
ABSORBED INTO THE DEEPENING LOW OFF THE B.C. COAST WEDNESDAY
MORNING. MEANWHILE...THE APPROACHING UPPER LEVEL JET STREAK
ROUNDING THE TROUGH BASE WILL FURTHER AMPLIFY THE SOUTHERN STREAM
WAVE AS IT APPROACHES CA LATE IN THE PERIOD. PRE-FRONTAL
STRENGTHENING ONSHORE SOUTH-SOUTHWESTERLY FLOW IN AN AXIS OF 3-3.5
STANDARD DEVIATIONS ABOVE THE MEAN PW ANOMALIES WILL SUPPORT
WIDESPREAD MODERATE TO HEAVY PRECIP TOTALS FROM THE CENTRAL COAST
RANGE INTO THE SOUTHERN-CENTRAL SIERRA...WHILE THE POST-FRONTAL
WESTERLY FLOW (STILL MOIST YET NOT NEARLY AS ANOMALOUS) WILL
RESULT IN ADDITIONAL MOD-HEAVY PCPN AMOUNTS ACROSS FROM THE BAY
AREA-NORTH COAST AND INTO THE SHASTA/SISKIYOUS AND NORTHERN
SIERRA. IN TERMS OF THE QPF...WPC AGAIN UTILIZED A MULTI-MODEL
BLEND OF (MAINLY) THE HIGHER RESOLUTION GUIDANCE...GIVEN THE
BETTER SENSITIVITY OVER THE TERRAIN.

A MARGINAL RISK OF EXCESSIVE RAINFALL WILL REMAIN ACROSS EASTERN
SACRAMENTO/SAN JOAQUIN VALLEYS INTO THE WESTERN SLOPES OF THE
SIERRA DURING THE DAY 1 PERIOD...AIDED BY THE WET ANTECEDENT
CONDITIONS AND (OVER THE HIGHER TERRAIN) ADDED CONTRIBUTION FROM
SNOWMELT.


...PORTIONS OF THE NORTHERN TO CENTRAL PLAINS...

WEAK SHORTWAVE ENERGY PUSHING EASTWARD FROM THE LEE OF THE
NORTHERN ROCKIES ACROSS PORTIONS OF THE NORTHERN TO CENTRAL PLAINS
WILL ENHANCE ISENTROPIC LIFT OVER THE LOW LEVEL COLD AIR BECOMING
ESTABLISHED ACROSS THE MID SECTION OF THE NATION.
FURTHERMORE...THE BACK-BUILDING UPPER JET STREAK ACROSS THE
NORTHERN PLAINS-UPPER MIDWEST WILL ENHANCE THE UPPER DIVERGENCE
AND LOW-MID LEVEL FRONTOGENESIS AT TIMES VIA THE RIGHT-ENTRANCE
REGION... PARTICULARLY EARLY (TUE AM) AND LATE (TUE NIGHT). THESE
FEATURES WILL SUPPORT A STRIPE OF PCPN WITH A MAX AROUND 0.25 INCH
NEAR/ALONG THE NE-SD BORDER. SEE THE LATEST QPFHSD FOR ADDITIONAL
WINTER WEATHER INFORMATION.


...LOWER MISSISSIPPI VALLEY / TENNESSEE VALLEY / SOUTHEAST...

ANOTHER ROUND OF ELEVATED CONVECTION...BUOYED TO A LARGE DEGREE BY
STEEP MID LEVEL LAPSE RATES (7.5-8.0+ C/KM BETWEEN 700-500 MB)
WILL ALIGN ALONG AND BEHIND THE QUASI WEST-EAST SURFACE FRONT
DROPPING INTO THE LOWER MS VALLEY-SOUTHEAST REGION DURING THE
PERIOD. THE MODEL QPF SPREAD IS NOT AS SIGNIFICANT TODAY AS IT WAS
YESTERDAY WHEN THE CONVECTION WAS FARTHER NORTH (MIDWEST-OH
VALLEY). WPC THEREFORE WAS ABLE TO INCORPORATE A MULTI-MODEL BLEND
(GFS/ECMWF/RGEM/PARALLEL NAM)...WHICH MATCHED UP FAIRLY WELL WITH
THE HIGH-RES MEANS.

GIVEN THE AVAILABLE INSTABILITY (MODEL MUCAPES AVERAGING 1000-2000
J/KG)...ALONG WITH THE POTENTIAL FOR TRAINING THIS AFTERNOON AND
EVENING AS THE WESTERLY LOW-LEVEL FLOW ALIGNS NEARLY PARALLEL TO
THE MEAN 850-300 MB FLOW... LOCALIZED SHORT-TERM RUNOFF ISSUES
WILL BE POSSIBLE...PARTICULARLY FROM SOUTHERN MO-NORTHERN AR ESE
THROUGH MUCH OF THE TN VALLEY WHERE THE ANTECEDENT CONDITIONS
(LOWER 1-3 HOURLY FFG VALUES) WOULD BE MORE CONDUCIVE.

HURLEY


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

24HR QP VT 22/12Z
 0.01 525254 522250 520245 518241 516236 514232 512226 511222
      511219 513219 517222 520226 522229 526232 531233 533234
 0.01 548171 542175 535182 532182 529179 524172 518164 510162
      508160 505155 504149 503142 506131 507124 510120 513118
      516115 518106 515106 513105 512102 510098 510091 508086
      503083 499082 496082 495084 489088 484096 475106 471108
      468109 466107 458103 453096 447094 441093 436092 433090
      428088 424091 422094 421101 421107 418110 415115 412119
      409124 408130 408137 411138 415137 416141 415144 413148
      409148 397147 390149 385150 383152 381156 382158 385156
      387155 389158 383181 375180 363178 358177 354179 347174
      344170 340167 330166 321169 317172 314176 313180 311183
      309188 307195 306201 305207 300212 294218 292221 296223
      306228 314224 328218 338217 340218 339221 337223 334228
      332234 332238 335242 339251 339254 338256 338261 338265
      340268 352272 359269 365265 374271 378273 382271 386270
      390272 394271 399273 408276 418276 427278 434282 451285
      456285 458285 460288 460300 461309 462311 464313 467316
      468320 466331
 0.01 512699 513692 512687 510673 509667 507663 504657 497653
      491654 480656 471659 464662 456661 449660 446659 443661
      441665 440670 440675 439680 441683 441688 437697 432713
      430716 430721 426726 427733 430734 433737 432742 429747
      428752 423758 422761 422765 425767 430765 434778 437780
      439777 443769 446761 448757 452755 454758 454761 453764
      452775 449783 446789 442796 439804 438810 440813 449812
      461804 467800 467808 466814 466820 467833 467840 466844
      466851 463851 460849 457849 447850 441853 439855 440858
      443861 446863 450863 452865 458871 460873 461876 461881
      461888 464899 465903 467906 470908 471906 474897 474884
      476872 479862 481855 484846 489831 493822 496815 505798
      512783 514774 514765 513750 510742 509739 509735 511731
      512720 511714 511707 512699
 0.01 463050 463044 461037 458025 458015 456008 455003 451997
      438982 433971 430956 428949 426944 421933 414924 410924
      407931 406989 403993 399996 396000 395007 397014 399016
      394016 388017 384020 382025 384029 388032 389034 393034
      395037 393038 390045 387045 385046 379046 378050 385049
      390055 393057 391061 391064 401059 407060 412060 415066
      419065 423077 425077 426074 428067 430064 431066 433070
      432073 437074 442073 447077 451078 450073 446069 443065
      440062 437056 436052 437048 442051 446055 449056 451059
      457059 461055 463050
 0.01 418045 416043 415040 412038 408038 405037 401037 398039
      398041 396046 397050 399053 402052 404050 408049 409049
      411047 415047 418045
 0.01 414019 413018 411018 409017 407017 406017 404019 406021
      407021 409021 411021 413021 414019
 0.01 399798 399792 397791 393791 390793 380801 374806 368809
      357817 357809 360802 362798 362793 361784 359772 358768
      356764 353763 352757 352747 354731 355723 354714 353710
      350707 344706 338709 332715 325727 320739 314753 313757
      313762 315772 317779 317785 317788 317798 319805 320810
      321814 324822 332835 341865 345881 349903 351922 353930
      353939 352951 350959 351974 351978 353981 355980 358977
      363972 365967 372954 374951 379950 384945 388940 390936
      390930 389922 387915 381896 380893 379889 376880 375871
      373866 373861 372841 374831 377825 381818 386813 399798
 0.01 364161 364159 364157 364155 362156 361156 360156 359158
      358158 357160 356160 356162 356164 356165 358165 360163
      362164 362163 364162 364161
 0.25 522267 517252 512239 505223 502215 500213 496211 489209
      485203 475208 470207 466206 459207 453208 447211 442213
      433212 426209 423210 421212 417212 413210 406206 402200
      395197 388194 383190 377185 372183 368181 363181 357183
      355185 355189 359195 362201 369204 374209 376212 375215
      366212 362206 361203 359200 354199 353195 350189 345184
      342178 339183 333188 329194 328199 329202 331206 335207
      341207 348210 352215 356220 359228 363233 364241 370240
      376237 377243 381248 388251 395254 401256 409256 416254
      422255 431257 434256 436254 439249 442246 445244 453246
      462250 468254 472258 476265 479272 480279 482288 482298
      480309 479316 481319 486323 490324 499323
 0.25 497678 496678 494677 493676 491676 489677 489678 488679
      487681 487682 486684 487685 489685 490684 492684 493683
      495682 496681 496680 497678
 0.25 485164 482157 479153 476149 473147 469147 466149 464154
      461175 458177 455174 452166 452158 452153 446152 440148
      436149 435155 438163 439167 442171 441181 442187 448187
      451188 454186 457184 461180 472173 479170 485164 485164
 0.25 447114 447113 445113 445114 447114 447114
 0.25 440012 440007 438004 434000 432995 430987 426982 424982
      423985 424994 425001 425004 427011 430016 435015 440012
 0.25 377929 378925 378919 377910 375902 373893 370879 364864
      362855 361847 360838 360833 358830 352827 351823 352819
      350800 348794 345793 342794 337798 336806 334821 335828
      338836 342850 347866 350873 352880 355897 358913 359920
      359932 359948 359952 361951 365950 367947 371943 373939
      377929
 0.25 342737 342728 338724 335728 332735 331741 330746 328753
      328757 330760 333760 335758 338753 341746 342739 342737
 0.25 321203 319202 318202 317202 317203 319204 321203
 0.50 519274 516261 514255 511247 501222 498219 494219 490224
      490232 487237 483238 481231 478225 474224 469227 464231
      462228 462223 459219 455220 453223 453225 455232 457234
      460236 463236 465239 474248 478252 482256 486269 490282
      490290 489301 487313 490318 494320 496317 501310 504306
      508303
 0.50 443220 438219 432219 425220 421224 414215 409214 404209
      400204 395200 388196 383193 377188 372185 368183 364184
      361185 360188 363193 367197 377207 382211 385216 381220
      377221 373219 370218 367219 365222 366224 371226 374226
      378228 380231 384236 388240 394245 401248 413248 421249
      428249 430248 430244 427238 423233 423228 428228 433227
      436225 443220
 0.50 374927 374920 374914 371903 363885 361882 361879 361872
      360867 358857 357843 356837 354834 345831 342832 341837
      344849 347859 351868 355875 357879 359882 359885 358896
      358901 359907 363929 364936 366939 370938 372934 374927
 0.50 350203 349200 348197 346194 345191 343190 340190 336188
      334191 333193 335194 337196 338200 340201 343204 347204
      350203
 0.50 349820 350818 350815 348813 346812 344812 343814 342816
      342819 343821 345822 347822 349821 349820
 0.50 339733 339732 339731 337730 336732 336733 335734 335736
      334738 334739 334741 334743 335745 337744 338742 339742
      339740 339738 339735 339734 339733
 1.00 504278 504273 501268 500264 499258 497252 494249 492248
      488249 488256 489260 492265 494269 496273 498278 503279
      504278
 1.00 415224 413219 406219 403213 399208 394203 387199 378191
      372188 369187 366188 367192 371197 377202 383206 392214
      398218 401219 404219 405222 407228 410235 415224
 1.00 404240 405238 403236 403235 402234 400234 398233 397232
      395232 393231 392231 391232 391233 392235 393235 394236
      396237 397238 398239 399240 401241 403241 404240
 1.00 371920 371918 370916 369914 368912 366913 366914 366916
      366918 367920 367923 367925 367927 367929 368930 369929
      370928 370927 371925 371923 371921 371920
 1.00 354861 354857 353852 353848 352844 351842 349840 346840
      346842 346847 347849 348853 349856 351859 352861 354861
 1.50 495257 495256 494254 493253 492253 491255 491257 492258
      493259 494259 495257
 1.50 413224 413222 411221 409221 408222 408225 409226 410227
      411226 412225 413224
 1.50 400213 400212 399211 398210 397208 395206 394205 393205
      392204 390204 389203 387203 387205 388207 390208 391210
      393211 394212 395212 396214 398215 400215 400213
 1.50 386203 385200 383197 381196 378194 376193 372193 370192
      372195 373197 375198 378201 380202 383203 386203

$$





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.