Quantitative Precipitation Forecast
Issued by NWS

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723
FXUS04 KWBC 170726
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
325 AM EDT TUE OCT 17 2017


PRELIM DAY 1 QPF DISCUSSION
VALID OCT 17/1200 UTC THRU OCT 18/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...

...FLORIDA PENINSULA...

THE SOUTHERN PERIPHERY OF AN UPPER LEVEL SHORTWAVE TROUGH ACROSS
THE FL PANHANDLE AND EASTERN GULF EARLY TODAY WILL PUSH SLOWLY
EASTWARD ACROSS THE FL PENINSULA BY EARLY WED. AT THE SURFACE...IN
LIGHT OF THE SLOW MOVING UPPER SHORTWAVE AND WEAK WESTERLY FLOW
ALOFT...THE FRONT IS EXPECTED BECOME STATIONARY ACROSS SOUTH FL
LATER TUE AND TUE NIGHT. WHILE THE BULK OF POST-FRONTAL
INSTABILITY IS EXPECTED TO REMAIN OFF THE EAST COAST OF
FL...SUFFICIENT MUCAPES WILL BE PRESENT DURING THE DAY 1 PERIOD
ALONG THE EAST COAST OF CENTRAL-SOUTH FL (1000-1500 J/KG DURING
THE DAY TUE...500-1000 J/KG TUE NIGHT). MEANWHILE...ROBUST
POST-FRONTAL LOW-LEVEL E-NE FLOW (25-30+ KTS AT 850 MB) IS ALSO
NOTED...WHICH IS HELPING TO MAINTAIN HEALTHY LOW-LEVEL MOISTURE
TRANSPORT DURING THE PERIOD AS 850 MB MOISTURE FLUX ANOMALIES
AROUND +1.5-2.0 PERSIST THROUGH TUE NIGHT. THE FAVORABLE MOISTURE
PROFILE AT BOTH LOWER LEVELS AND ALOFT (WITH THE SW FLOW) WILL
MAINTAIN THE ANOMALOUS PW VALUES OF 1.75-2.0 INCHES (WITH LAYER
PWs OF  AROUND 0.25" BETWEEN 500-300 MB).

IN LIGHT OF THESE FAVORABLE THERMODYNAMIC PARAMETERS...ALONG WITH
THE SUBTLE YET PROLONGED RIGHT-ENTRANCE REGION UPPER JET FORCING
(UPPER DIVERGENCE...LOW-MID LAYER FRONTOGENESIS)...THE LATEST
MODEL GUIDANCE (ESPECIALLY HIGH-RES CAMs) CONTINUE TO INDICATE
HEAVY RAINFALL TOTALS ALONG THE EAST COAST OF FL BETWEEN PALM
COAST AND VERO BEACH. UTILIZING A MULTI-MODEL BLEND WITH THE
QPF...PARTICULARLY WITH THE HIGH-RES CAMs...HIGHEST AREAL-AVERAGE
TOTALS OF 1.5-3.0+ INCHES WERE NOTED (HEAVIEST NORTH OF THE CAPE).
THE 27KM ECMWF AND GFS OUTPUT WERE NOTABLY MORE CONSERVATIVE WITH
AMOUNTS...ESPECIALLY INLAND...LIKELY OWING TO THE PROGGED
INSTABILITY GRADIENT ALONG AND EAST OF THE COAST. FOR NOW HAVE
LEANED TOWARD THE HIGH-RES MEANS GIVEN THE STRONG LOW-LEVEL
ONSHORE FLOW AND THETA-E TRANSPORT...WHICH RESULTED IN LITTLE
CHANGE FROM THE PREVIOUS FORECAST (CONTINUITY) OUTSIDE OF A SLIGHT
SOUTHWARD SHIFT OF THE MAX AMOUNTS. IN LIGHT OF THIS...MINIMAL
CHANGES WERE MADE TO THE EXCESSIVE RAINFALL OUTLOOK (MARGINAL AND
SLIGHT RISK AREAS) THAT WERE INHERITED FROM YESTERDAY`s DAY 2
ERO...WHICH ARE SUPPORTED BY THE LATEST (00Z) SSEO 40KM
NEIGHBORHOOD PROBABILITIES OF QPF>FFG EXCEEDANCE (INCLUDING 30-70%
PROBS WITHIN THE SLIGHT RISK AREA BETWEEN 15-00Z).



...PACIFIC NORTHWEST...

A STRONG UPPER JET STEAK ACROSS SOUTHERN B.C. WILL DROP SOUTH OF
VANCOUVER ISLAND EARLY TUE AND THEN INTO NORTHERN WA DURING THE
DAY TUE. INCREASING UPPER DIFFLUENCE AND DEEP LAYER WARM/MOISTURE
ADVECTION ASSOCIATED WITH THE WARM CONVEYOR BELT (WCB) AHEAD OF
THE FAST MOVING UPPER SHORTWAVE TROUGH WILL SUPPORT MOD-HEAVY PCPN
ACROSS THE WA COASTAL AND CASCADE RANGES THROUGH 18Z TUE OR PRIOR
TO THE PASSAGE OF THE UPPER SHORTWAVE AND SURFACE COLD FRONT.
THEREAFTER...FLAT SHORTWAVE RIDGING...WEAKENING WESTERLY 850-700
MB FLOW...AND A SIGNIFICANT DROP IN PW VALUES WILL LEAD TO LOWER
ADDITIONAL OROGRAPHICALLY-ENHANCED AMOUNTS ACROSS THE WESTERN
SLOPES THIS AFTERNOON...WITH MINIMAL ADDITIONAL ACCUMULATIONS
OVERNIGHT AHEAD OF THE NEXT STRONG UPPER JET STREAK/AMPLIFYING
UPPER TROUGH THAT WILL BRING A RESURGENCE OF HEAVY PCPN INTO THE
PAC NW DURING DAYS 2 AND 3 (SEE BELOW).

HURLEY


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

24HR QP VT 18/12Z
 0.01 528246 524247 523244 524240 525231 528224 534212 536208
      538201 540195 542189 542179 540173 538171 537167 535162
      533157 530153 520150 514148 510145 507142 501140 496138
      492134 489131 485128 479125 475127 471125 472132 470136
      470139 473141 478140 483142 481145 476147 470145 468141
      463141 459143 458150 456155 458161 462160 466162 467164
      469168 471166 473167 477172 478176 479183 482188 484193
      488195 485197 481199 478201 473202 469208 465209 461207
      455214 445216 441217 441223 443236 440238 438243 441248
      445251 450252 452258 452274 451281 451288 448295 446303
      445312 446323
 0.01 520672 517669 514669 506667 502667 499661 497655 495647
      495640 493634 491629 487626 483624 478626 474628 471632
      470642 471645 473647 477647 481643 486641 489642 488646
      485645 482647 480653 480658 479665 478671 474680 476684
      476690 469698 467700 462703 459704 457706 454705 452708
      454710 457715 461716 466718 469722 473728 476731 477738
      468744 467749 468755 468759 470761 472766 475767 476774
      477781 479785 483791 485793 493797 508802 522811 528815
      532817 537816 542816 545813 549809 551805 551795 549784
      548777 547771 548767
 0.01 549071 550058 551044 550034 547025 542008 540005 536005
      531010 522023 520030 518034 518041 516051 516057 517061
      517072 519083 522089 527095 531098 538094 542089 546082
      549071
 0.01 489691 488688 487687 486687 484688 483690 483691 481693
      480695 478694 476695 475697 474700 475701 477701 479701
      480699 482698 484698 484697 485696 486695 487694 488692
      489691
 0.01 463179 464176 463175 461174 460175 459176 458177 457179
      455181 454184 455185 457185 457184 458184 460183 460182
      462181 462180 463179
 0.01 454176 454174 453173 451173 451175 451176 452176 454177
      454176
 0.01 449726 447726 446727 444727 444730 446729 448729 449727
      449726
 0.01 446712 444712 442713 441713 441714 441716 443716 444715
      446712 446712
 0.01 444740 444737 442737 442738 440740 439740 438741 437743
      436744 435744 436746 437746 438746 439743 441743 442740
      444740 444740
 0.01 372193 373188 373186 370185 366184 363182 361181 360183
      362186 364187 366185 369187 370190 372193 372193
 0.01 331750 329737 327736 323736 319740 311748 304757 302760
      297763 291763 286764 281762 276765 273768 272775 272787
      267792 262794 258796 255801 251806 250808 250812 249814
      247807 246797 243795 236796 231798 233802 233810 232815
      229818 226824 225831 225838 227844 230855 242856 247858
      251862 254875 257889 258895 260901 264905 268907 272906
      274904 276899 279895 281890 283878 285872 287866 286851
      284843 283835 284829 287826 296819 302818 306814 312803
      317794 322784 325777 324773 324770 325767 328762 330756
      331750
 0.25 535201 537194 537186 533176 532171 531166 524160 517154
      513154 509150 507147 502145 495144 493142 491147 497153
      505158 501158 497160 493161 490164 486165 485167 487169
      495187 498190 500191 503190 505191 506197 508199 511204
      518210 522211 526211 529209 533206 535201
 0.25 546063 547052 547044 547039 546034 543027 539027 536035
      534043 533050 532061 535069 536071 539071 544068 546063
 0.25 522267 517253 515245 514234 512227 508220 506216 506211
      506200 506197 503197 499203 496204 492202 490199 486200
      485202 481202 476206 471210 465212 460216 458217 454217
      460230 455234 453237 456240 460242 462244 465247 466252
      467258 469263 474263 480262 483262 481266 479275 477281
      475284 468298 465305 464311 463317 464325 470330 476333
      482332 487329 493325 502317
 0.25 540767 538755 535746 530738 525732 520727 517725 514725
      511727 506727 504725 504717 501718 500723 499728 496732
      493740 493746 494753 498761 503769 512781 518787 519787
      523784 528777 529774 533774 536775 539775 540767
 0.25 508262 507255 503249 500245 495240 493235 490229 485230
      487236 491237 492240 494247 497252 500258 506263 508262
 0.25 495707 496704 494703 493703 492702 491702 489703 488703
      486704 485706 484707 485710 486712 487712 489712 490712
      492712 493711 494710 495708 495707
 0.25 484232 484230 483229 483227 483224 482224 481222 480221
      479221 478220 477220 476222 475222 474224 475226 476227
      477228 478228 480230 481231 481233 483233 484232
 0.25 486161 485159 484158 484156 482154 480155 480156 482157
      483158 482161 483162 485162 486161
 0.25 467230 466228 465228 464229 464230 466231 467230
 0.25 470153 469150 467152 467153 469154 470153
 0.25 314764 314759 309760 303764 287770 280771 277774 277778
      277783 276789 271793 267795 264798 263799 266802 272806
      278811 283816 286818 290818 297815 301813 301808 310796
      313788 314783 313777 314764
 0.25 277869 278863 278857 276846 273843 270839 264834 258829
      255826 253824 250826 247827 244825 242821 242815 240814
      237815 235818 233822 231826 230836 230842 232848 235850
      239850 244851 249852 253858 260864 261867 262874 262886
      263892 265896 269898 272894 275886 276882 277875 277869
 0.25 262803 261802 259802 259803 258805 257805 256806 254807
      254808 253810 253812 255813 255814 257815 259814 259813
      260811 260809 260807 260805 261803 262803
 0.50 545052 545049 546047 546044 546041 545039 545038 544036
      542036 541038 540041 540043 539046 539048 539051 539054
      540055 542056 543055 544054 545052 545052
 0.50 533190 530175 528169 524165 520160 515157 512162 511166
      508164 503161 500160 498162 496164 496166 497174 501178
      504185 508189 511195 515195 519200 524200 526196 526191
      530192 532192 533190
 0.50 516281 512279 508275 505271 500267 493274 487282 480292
      475301 473306 470314 471320 476324 481323 485322 493317
      501311 507305
 0.50 527201 528199 527198 527199 526201 527202 527201
 0.50 508240 508232 506224 502212 498207 492204 491202 488203
      485204 482204 478207 474209 470215 467214 465216 465221
      466224 469222 474220 480220 484223 491226 496237 503243
      508240
 0.50 511160 511157 510155 510154 509152 509151 508150 506149
      504150 504151 504153 505155 506156 507157 508159 510160
      511160
 0.50 491250 492245 491242 488241 486235 481234 478230 473229
      469233 463233 463238 465241 469243 472246 476247 482248
      489251 491250
 0.50 495171 494169 493168 492168 491170 489167 488167 487167
      488167 489167 491170 492171 494172 495171
 0.50 309784 309776 307767 296769 291772 286775 282775 279777
      280782 280788 277793 272796 269798 270802 274804 278809
      282811 286816 292816 297813 301802 306793 309784
 0.50 273882 273876 273870 271864 268861 263856 261852 260846
      261841 262837 257832 255829 253829 250832 248837 245838
      242835 240823 238820 235821 233830 231840 233846 237848
      248847 254852 258860 261862 263866 264871 264878 264884
      265890 267893 271890 273882
 1.00 524179 524176 523174 523173 522171 522170 521169 519168
      519167 518164 516164 516166 517169 517170 519171 519172
      520174 520175 521178 523179 524179
 1.00 514187 514184 513183 511182 509182 508181 506181 506182
      508183 509184 511184 512186 514187 514187
 1.00 513179 514176 514173 512172 511170 509168 509167 508166
      506164 505163 503164 502165 503166 504168 505169 506170
      507172 508175 509175 510177 511178 512178 513179 513179
 1.00 501230 501225 499222 500219 499214 498210 495208 490208
      483208 477210 474213 475217 480218 484221 488222 491224
      493227 495231 498233 501230
 1.00 485243 486241 485238 484240 485243 485243
 1.00 482242 482240 482239 481236 480233 479233 478232 476232
      474231 474232 472233 472234 472236 472237 472239 473240
      475242 476242 476243 478244 479244 481244 481243 482242
 1.00 470218 468217 470218 470218
 1.00 303780 303776 299775 294780 287785 285791 283799 279805
      284810 288814 292814 295812 297805 299798 302789 303782
      303780
 1.00 269886 269884 269882 269880 268878 268880 267882 267884
      268886 269887 269886
 1.00 269872 268870 268869 267870 268872 268873 269872
 1.00 240841 240839 239837 238836 236834 236836 235837 234838
      234840 235842 237843 239843 240841
 1.50 496226 496223 495223 494224 494225 496226 496226
 1.50 496215 496213 497210 496210 495210 494212 494213 492214
      491214 492216 494216 495217 496215
 1.50 490219 490214 488210 486209 484209 481210 479211 477213
      475214 477216 480216 482219 485220 486220 490219
 1.50 479241 479238 478238 477240 476238 476235 475237 475238
      477240 478241 479241
 1.50 297794 297790 291789 288793 287797 285801 281804 282806
      285810 288812 290813 293811 295809 296803 297798 297794
 2.00 295805 294803 294801 294799 292797 292795 290795 289797
      289799 288800 287802 287803 285804 286806 286808 287810
      288810 289812 290812 291812 293810 293809 294807 294805
      295805
 3.00 292809 292807 292805 291804 290805 289807 289808 289810
      291810 292809

$$





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