Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 240658
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
258 AM EDT FRI OCT 24 2014


PRELIM DAY 1 QPF DISCUSSION
VALID OCT 24/1200 UTC THRU OCT 25/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

18Z UPDATE...
SLOWED THE NWD SPREAD OF HEAVIER PCPN THROUGH NEW ENGLAND GIVEN
RADAR TRENDS WHICH ARE SUPPORTED BY LATEST MULTI MODEL CONSENSUS.
ELSEWHERE..ONLY MINOR CHANGES TO PRELIM GUIDANCE BASED ON
SATL/RADAR TRENDS.

...NEW ENGLAND...

THE CLOSED LOW JUST OFF THE SOUTHERN NEW ENGLAND COAST WILL BE
PIVOTING SLOWLY NORTHEASTWARD TO OFF THE COAST OF ME BY EARLY
FRIDAY. THE LATEST IR/WV SAT IMAGERY CONTINUES TO SHOW A
WELL-DEFINED MID LEVEL DEFORMATION ZONE INTERACTING WITH
PERSISTENT AND STRONG ONSHORE EASTERLY FLOW. HOWEVER...DRIER AIR
AS SEEN IN THE LATEST WV IMAGERY IS SEEN WRAPPING AROUND THE MID
LEVEL LOW CENTER WHICH IS ALLOWING THE BANDS OF HEAVIER RAIN THAT
HAVE BEEN ADVECTING INLAND FROM THE ATLANTIC OCEAN TO BECOME
WEAKER AND MORE DISORGANIZED. THE GLOBAL MODELS AS PER THE 12Z GFS
AND THE 00Z ECMWF STILL SUPPORT AT LEAST BROKEN AREAS OF MODERATE
TO HEAVY RAIN IMPACTING ESP CENTRAL AND NORTHERN MAINE THROUGH
TONIGHT AND EARLY FRIDAY AS THE DEFORMATION ZONE PIVOTS FARTHER
NORTH AND CROSSES THIS REGION. THE STRONGER FORCING THOUGH SHOULD
BEGIN TO PULL AWAY AFTER 12Z FRIDAY...AND WITH DEEPER MOISTURE
GRADUALLY BECOMING MORE DETACHED FROM THE STRONGER DYNAMICS.
THEREFORE...EXPECT RAINS TO BEGIN TAPERING OFF LATER FRIDAY ACROSS
MAINE. ADDITIONAL RAINFALL AMOUNTS OF 1 TO 2 INCHES WITH ISOLATED
HEAVIER AMOUNTS ARE POSSIBLE. WPC QPF LEANED TOWARD A CONSENSUS OF
THE GFS/ECMWF AND UKMET.


...PACIFIC NORTHWEST INTO NORTHWEST CALIFORNIA...NORTHERN
ROCKIES...

THE LATEST BLENDED TPW/GOES-SOUNDER IMAGERY CONTINUES TO SHOW A
WELL-DEFINED PLUME OF HIGHER PWATS ASSOCIATED WITH AN ATMOSPHERIC
RIVER STRETCHING ACROSS THE CENTRAL AND EASTERN PACIFIC OCEAN AND
INTO THE PACIFIC NORTHWEST ALONG AND A SURFACE COLD FRONT WHICH IS
EXPECTED TO ACTUALLY STALL OUT OVER FAR NORTHERN CA AND INTO THE
NORTHERN GREAT BASIN OVER THE NEXT 12 HOURS OR SO. NUMEROUS SHWRS
WILL CONTINUE ALONG THE FRONT GIVEN THE DEEP PACIFIC FETCH OF
MOISTURE AND SUSTAINED ONSHORE FLOW...ESP FOR THE COASTAL RANGES.
THE SHWR ACTIVITY WILL OVERSPREAD THE NORTHERN ROCKIES AS THIS
PORTION OF THE FRONT CROSSES TONIGHT. THE ADDITIONAL RAINS THIS
PERIOD ACROSS THE NORTHWEST SHOULD NOT BE AS HEAVY AS WHAT HAS
BEEN SEEN OVER THE LAST COUPLE OF DAYS AS THE INITIAL SHORTWAVE
TROUGH THAT HELPED DRIVE THIS MOST RECENT HEAVY RAINFALL EVENT
WILL BE MOVING INTO SOUTHWEST CANADA. HOWEVER...BY LATE FRIDAY...A
NEW SHORTWAVE WILL BE AMPLIFYING OFFSHORE THE WEST COAST AND
INTERACTING WITH THE SAME FRONTAL ZONE AND MOISTURE FEED. A NEW
CONCENTRATED AREA OF HEAVIER RAINS WILL BE APPROACHING THE WA/OR
COASTAL RANGES BY LATE FRIDAY AS A RESULT.


...MIDWEST...

THE MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THE EASTWARD
ADVANCE OF A SHORTWAVE TROUGH OUT ACROSS THE NORTHERN/CENTRAL
PLAINS AND INTO THE UPPER MS VALLEY THROUGH THIS EVENING AND
OVERNIGHT. THE FRONT ASSOCIATED WITH THIS SYSTEM WILL BE WEAKENING
WITH TIME AND THERE IS EXPECTED TO BE A DECREASE IN SHOWER
ACTIVITY THROUGH EARLY FRIDAY AS IT CROSSES THE MIDWEST. ONLY LGT
RAINFALL AMOUNTS ARE EXPECTED WITH THIS FEATURE. WPC FAVORED A
BLEND OF THE GFS AND ECMWF.


...SOUTH FLORIDA/KEYS...

A VERY STRONG MOISTURE GRADIENT IS SITUATED OVER SOUTH FL IN
PROXIMITY TO A FRONTAL ZONE DRAPED W/E ACROSS THE AREA. VERY DEEP
TROPICAL MOISTURE IS POOLED OVER THE SOUTHEAST GULF OF MEXICO AND
ESP THE NORTHWEST CARIBBEAN SEA WITH SOME OF THIS FOCUSED EAST
ACROSS THE FL KEYS. NUMEROUS SHWRS/TSTMS ARE EXPECTED TO BE
FOCUSED AGAIN ALONG AND ESP SOUTH OF THE AFOREMENTIONED
FRONT...AND THE CONVECTION WILL BE ENHANCED LOCALLY IN THE
VICINITY OF A FRONTAL WAVE WHICH IS FORECAST TO DEVELOP AND MOVE
THROUGH THE FL STRAITS ON ITS WAY TO THE BAHAMAS BY LATE FRIDAY.
THE CONSENSUS OF GLOBAL MODEL SOLNS INSIST THAT THE HEAVIEST RAINS
WILL REMAIN SOUTH OF THE KEYS...BUT SUFFICIENT FORCING AND
INSTABILITY IS EXPECTED TO FOCUS AT LEAST SOME BROKEN COVERAGE OF
MODERATE TO HEAVY RAINFALL OVER THE FL KEYS. HOWEVER...WITH MUCH
DRIER AIR JUST TO THE NORTH...THE RAINFALL GRADIENT SHOULD BE VERY
TIGHT.

ORRISON

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

24HR QP VT 25/12Z
 0.01 492606 501634 500640 499653 496665 493677 491682 487687
      480693 474703 468712 465715 460719 440719 431706 427700
      428695 432689 436681 439677 441674 440670 437667 434663
      433657 435652 437647 440644 445640 454620 492606
 0.01 373288 384301 423315 449301 458302 462301 464299 467295
      468288 472281 476275 480271 484266 486262 488262 491270
      495278 500285 502287 505288 508285 507280 503267 500258
      496250 495245 498240 501242 503244 505243 505240 501233
      504229 506227 507221 508207 508203 508196 507193 507186
      508180 512176 512173 511170 508167 508160 510154 509151
      507147 505146 502143 497142 494140 491137 486131 480129
      476128 472128 469127 466131 463126 458126 452131 448138
      445142 442142 437142 434149 433155 433160 434163 433166
      430173 422190 419202 416209 412213 409216 408222 405227
      399228 392225 386223 383223 376224 369225 356228 344231
      338234 333238 332239 335242 341247 342247 359245 370246
      377253 378255 374265 372269 370275 373288
 0.01 547852 547839 546828 543818 540810 533800 521794 510790
      507789 504789 496788 481791 474793 468798 465804 463811
      463821 464831 470848 473853 480857 480869 482876 483882
      485884 488884 491881 494876 496868 497865 500860 505865
      510871 512877 516885 521890 528889 533886 538881 540879
      543874 547852
 0.01 464112 464109 461108 458108 456105 455102 453100 451100
      451105 449109 447109 447112 448114 452115 454115 456113
      459111 462112 464112
 0.01 271793 271788 270783 265778 256777 246779 237781 232786
      230795 229805 228813 227816 227823 230844 232847 235846
      244844 250839 252830 256825 258822 258815 259811 261809
      267803 268800 270798 271793
 0.25 487609 491632 492651 492658 491664 489671 486676 477686
      474690 468694 462693 460692 459687 460680 462673 463666
      464658 463640 462633 466618 487609
 0.25 415311 424309 432305 440300 450294 458288 464282 467278
      471272 474265 478261 491245 490237 486233 483232 482229
      479226 475227 471227 466228 462230 459230 462225 467222
      471218 476217 479215 484217 487222 491222 493220 494216
      491210 484209 482206 480206 478205 472206 468207 466206
      463204 460205 457210 452213 447215 443216 438213 436217
      435225 437226 439224 445228 449228 449232 445234 435236
      433231 429232 426235 420235 413235 409237 396236 393238
      393242 400249 403252 404254 401258 394268 392274 394279
      415292 417294 414296 410298 406300 402301 401303 401306
      415311
 0.25 454231 454228 452230 454231 454231
 0.25 453159 453157 451157 450158 449160 449163 450165 452163
      452161 453159
 0.25 266792 265784 261781 246783 240785 237790 233802 233815
      233822 234829 238832 243830 247819 250815 253810 258807
      261802 264798 266792
 0.50 486614 487623 488632 489649 488657 486664 480675 473685
      467687 464683 465677 468671 470664 468654 467645 466637
      469631 474629 478626 480616 486614
 0.50 485246 485241 483239 480234 479231 477230 472236 451241
      445242 439241 434242 428238 417241 415248 413260 406269
      404275 406277 410279 417281 423285 425286 425290 421296
      413304 412307 416307 421306 431300 442294 450289 460280
      467272 474259 479251 485246
 0.50 459217 460215 460214 459215 459217 459217
 0.50 262794 262784 254784 245785 241787 239789 237797 236806
      238808 241807 248804 250807 252809 258804 261799 262794
 1.00 472254 470251 468249 461249 454248 451247 448248 436250
      425254 423259 423263 418268 417271 419273 427276 432278
      434282 436285 442285 447283 456274 464263 469259 472254
 1.00 259799 259793 257789 258787 252787 249790 247793 245797
      243801 248801 252802 252806 255806 257802 259799
 1.50 455261 456257 454254 451252 447252 442254 437255 432258
      428262 425266 423270 426271 431271 435272 438275 442271
      446266 450264 455261
 1.50 258799 258797 257795 257794 255794 253794 251795 249795
      248796 248797 246798 246799 248799 250798 252799 253799
      254800 255801 255803 256803 256801 257801 258799
 2.00 440263 438262 437262 435260 433261 432263 431265 432267
      434267 436267 438266 438265 440263 440263

$$





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