Quantitative Precipitation Forecast
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
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 48 49 50
328
FXUS04 KWBC 050624
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
123 AM EST FRI FEB 05 2016


PRELIM DAY 1 QPF DISCUSSION
VALID FEB 05/1200 UTC THRU FEB 06/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1

...MID ATLANTIC COAST AND NEW ENGLAND...

COASTAL LOW PRESSURE IS FORECAST TO DROP JUST BELOW 1000 MB BY 00Z
SATURDAY AS IT COMES WHIPPING UP THE COAST TODAY...MOVING FROM OFF
NORTH CAROLINA TO OFF OF MAINE...PASSING NEAR THE 70/40 BENCHMARK.
THE SYSTEM WAS FORMING IN THE ENTRANCE REGION OF AN IMPRESSIVE 180
KNOT ANTICYCLONICALLY CURVED UPPER JET...WITH A SHARPLY DEFINED
SHORTWAVE TROUGH LIFTING UP FROM THE SOUTHERN APPALACHIANS. MODELS
CONTINUED TO TREND WETTER ALONG THE NEW ENGLAND COAST FROM LONG
ISLAND TO MAINE...AND WPC INCREASED 24-HOUR QPF AMOUNTS BY 0.10
INCHES ALONG THIS ZONE...SLIGHTLY MORE ALONG THE MASSACHUSETTS
CAPE...WHERE TOTAL PRECIPITATION BEYOND 12Z TODAY MAY EXCEED ONE
INCH LIQUID. WHILE SOME OF THAT WILL BE RAIN OUT OVER THE
CAPE...SNOW IS EXPECTED AS THE DOMINANT PRECIPITATION TYPE FARTHER
WEST. PLEASE REFER TO THE QPFHSD...HEAVY SNOW DISCUSSION...FOR
DETAILS.

THE QPF WAS BASED ON A 40/30/30 BLEND OF PREVIOUS WPC / 00Z NAM /
00Z NAM CONEST. THE NAM WAS FAIRLY REPRESENTATIVE OF TRENDS IN THE
GLOBAL AND ENSEMBLE GUIDANCE. THE CONEST LEANED A BIT FARTHER EAST
WITH THE HEAVIEST PRECIPITATION...ESPECIALLY THAT WHICH WILL BE
CONVECTIVE NEAR THE TRACK OF THE SURFACE LOW...SO THE CONEST WAS
USED TO TEMPER THE TENDENCY OF THE NAM TO SPREAD HEAVY AMOUNTS TOO
FAR NORTH AND WEST INTO THE DRIER CONTINENTAL AIR. AGAIN...THE
OVERALL CHANGE TO THE FORECAST WAS FAIRLY MINIMAL...BUT DOES HAVE
IMPLICATIONS FOR THE WINTER WEATHER DETAILS...INCLUDING MAJOR
POPULATION CENTERS IN THE NORTHEAST.


...PACIFIC NORTHWEST...

A BRIEF PERIOD OF SOUTHWESTERLY ONSHORE FLOW WILL BE FOLLOWED BY A
SHARP WIND SHIFT AND THEN WESTERLY FLOW BEHIND A COMPACT AND
PROGRESSIVE SHORTWAVE TROUGH. THIS FEATURE WILL FOCUS ANOMALOUS
MOISTURE FLUX INTO THE COASTAL RANGES AND CASCADES FOR SEVERAL
HOURS FRIDAY AFTERNOON/EVENING. AS THE WAVE CONTINUES DOWNSTREAM
INTO THE NORTHERN ROCKIES IT SHOULD LOSE THE CONNECTION TO PACIFIC
MOISTURE...AS THE SHARPNESS OF THE WAVE AND SHORT WAVELENGTH
LEAVES THE CORRIDOR OF MORE FAVORABLE PW VALUES PINCHED OFF IN AN
AREA OF WEAKER LOW LEVEL FLOW OFF THE NORTHERN CALIFORNIA COAST BY
SATURDAY MORNING. AS SUCH...THE MODELS AND ANALOG EVENT DATA FROM
THE GEFS REFORECAST EFFORTS SUGGEST RELATIVELY HEAVY 24-HOUR
AMOUNTS WEST OF THE CASCADES...AND LESS THAN A HALF INCH AREAL
AVERAGE FARTHER EAST INTO IDAHO. MODEL AGREEMENT WAS
GOOD...ALTHOUGH THE 12Z ECMWF...AND AGAIN THE 00Z RUN...WAS QUITE
FLAT WITH THIS WAVE...AND FORECASTS LESS PRECIPITATION. WPC LEANED
ON THE SIDE OF CONSENSUS...AWAY FROM THE DRIER ECMWF...AND THE
PREVIOUS FORECAST GRIDS INCLUDED SUCH GOOD DETAIL THAT WE
INTRODUCED NEARLY ZERO CHANGE IN THE 06Z UPDATE.


...UPPER MIDWEST AND GREAT LAKES...

A LOW AMPLITUDE AND MOISTURE STARVED TROUGH WILL PRODUCE LIGHT
PRECIPITATION AND A SMALL AMOUNT OF LAKE EFFECT SNOW. MODELS OFTEN
STRUGGLE TO PROVIDE MUCH DEFINITION WITH WIDESPREAD PRECIPITATION
BETWEEN 0.01 AND 0.10 INCHES. WPC STARTED WITH A BLEND OF THE 00Z
GFS/12Z ECMWF AND 18Z GEFS MEAN GIVEN THEIR SIMILARITIES...AND
USED SOME OF OUR IN-HOUSE DOWNSCALED QPF AND PROBABILISTIC FIELDS
TO FILL IN THE DETAILS.


...COLORADO TO TEXAS...

THE SOUTHERN STREAM WAVE IN A DEVELOPING SPLIT FLOW WILL DIG INTO
THE SOUTHERN PLAINS. LIGHT SNOW WAS ALREADY ONGOING IN COLORADO AT
06Z. THE SYSTEM AS A WHOLE MAY BE LESS EFFICIENT AT PRODUCING
MEASURABLE PRECIPITATION AS IT COMES OUT ONTO THE LOWER TERRAIN
FROM KS TO W TX EARLY TODAY...BUT ASCENT WILL THEN INCREASE AS THE
WAVE SPINS UP AT LOWER LATITUDE...AND A MODEST RETURN FETCH OF
MODIFIED GULF MOISTURE BEGINS TO MOVE INTO TEXAS. THE GFS AND
ECMWF ARE FAIRLY SIMILAR IN DEPICTING LOCAL MAXIMA OF
PRECIPITATION FROM OK INTO NORTHEAST TX ALONG THE AXIS OF DEEPEST
FORCING...AND ANOTHER IN CENTRAL TEXAS NEAR THE RETURNING
MOISTURE. THE GEM REGIONAL MODEL AND ECMWF ENSEMBLE AND GEFS
PROBABILITIES WERE ALSO USEFUL IN CRAFTING QPF HERE...WITH EVENT
TOTALS REMAINING QUITE LIGHT...UNDER A HALF INCH AT BEST.

BURKE

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

24HR QP VT 06/12Z
 0.01 477618 483625 487635 489648 489653 487658 475672 463688
      458697 453704 449712 445718 439726 433732 426739 418745
      410750 403756 388763 380766 371766 361767 355767 351767
      349766 343766 339764 336763 333767 328773 323780 318787
      313793 302808 298811 293813 286814 278811 272808 264804
      261802 258805 244818 238818 235820 234826 231828 229827
      229820 228815 227813 233796 236787 240778 245771 252766
      260763 264762 268764 272766 271770 270773 268777 265781
      263786 267790 271791 272795 277794 282792 285789 295779
      307767 314761 324755 331749 336743 341736 345730 356716
      362710 372703 380698 384691 388683 393677 398669 403662
      410655 414651 418647 427640 437632
 0.01 541203 534177 533173 532170 526166 517159 500146 483129
      476128 472125 468125 469131 469133 466134 462130 455130
      450131 451137 454139 454143 444146 437138 435143 434152
      440164 442169 440174 434184 432186 431191 430196 431200
      434205 431211 424217 417226 407232 399240 394240 391243
      388250 387256 385265 381273 378288 381290 385288 389286
      394287 393294 401297 406300 412303 424307 435311 442312
      449314 470314 480313 491311 499307 508300 524262 523259
      523258 523256 523254 522251 523248 523246 523243 524240
      524238 525235 525233 525230 526228 526225 527223 527220
      528218 530219 531220 532222 534223 536224
 0.01 504826 503821 502819 499814 496812 489812 483814 481816
      478817 475818 472820 469820 465819 463814 458810 455807
      455801 455796 456792 455784 451779 448782 447790 444797
      441801 438805 436806 435811 433816 439815 440813 442815
      444817 453823 455829 455835 449844 445858 442873 441887
      441904 441911 438918 431947 429953 428955 428960 429966
      433971 436976 440983 441989 443993 444998 444003 446007
      448010 453010 456008 462996 467986 478959 487934 496906
      499891 501878 502867 502859 501839 504826
 0.01 456113 454105 453100 448095 445096 441101 437105 438110
      441115 443120 446123 450119 454115 456113
 0.01 441755 440748 436746 435749 435756 435761 434766 434773
      436780 437777 438772 440767 440762 440755 441755
 0.01 435787 431785 429781 427781 424781 422780 422782 419785
      413784 414791 418795 420799 424801 427798 427796 428793
      428788 429784 431785 435787
 0.01 414064 414061 412060 411059 407058 404058 402056 398055
      391063 389066 389070 390073 396066 402058 406061 407063
      405065 402065 401069 397073 399076 403074 408075 412072
      412068 410066 414064
 0.01 417970 416966 412963 409968 407973 399000 398006 395011
      390022 383029 378031 373030 366034 362038 362041 365043
      363054 365052 368053 374054 379051 382047 396030 401021
      404007 408996 412982 417970
 0.01 403792 402792 400793 398793 396793 395793 393794 391796
      390796 388797 388799 390797 391796 393796 395796 397796
      398795 400795 402792 403792 403792
 0.01 368985 361972 363968 363962 359956 353952 349951 346949
      330944 316940 312939 309941 307943 305947 297949 293949
      289948 283945 278937 272935 265935 257939 254945 254956
      257961 261966 268971 280978 290989 296994 298996 302996
      315988 321986 324983 325980 329978 333978 338978 341979
      342982 344986 344991 344002 345004 349005 355000 364994
      368985
 0.01 256795 254792 252790 250789 247789 247791 248794 248798
      247800 245803 244805 242807 245807 247805 248803 250801
      252799 254797 256795
 0.25 461623 468624 474629 478638 479644 478651 470665 466672
      461680 451692 440705 430717 418729 406739 398744 391745
      382746 375746 370747 365746 361745 360740 362732 366726
      370719 376712 386701 396687 405675 417662 427650 438637
      444632 450627
 0.25 519274 520263 519253 518243 515232 511225 508219 503212
      498204 496201 492199 484199 479201 472206 466209 460211
      446216 439217 434220 428235 419234 413236 409242 407245
      405252 407261 408265 410268 421280 425281 430283 437284
      445285 453287 461288 468288 474291 483295 492298 497297
      504294 510289 515283 519274
 0.25 529204 530198 531191 526182 521176 515171 508167 504165
      500165 497165 493163 487158 484156 481155 477157 473157
      469157 467160 467166 470168 475171 477173 481181 483186
      485189 489188 494188 501188 506188 510190 520203 525207
      529204
 0.25 483857 483852 482847 480844 478842 476842 474843 473845
      473850 473853 475857 476860 479862 482859 483857
 0.25 451173 451173
 0.50 517273 519263 518253 513235 510228 506221 502215 496208
      490205 483204 477206 471210 460215 453218 450223 456226
      455230 453231 446233 441237 435240 427238 419236 416237
      413243 414248 416251 419257 421260 424262 429263 433261
      444257 447256 451256 458261 463261 470265 476270 481276
      491287 495290 499291 505289 512282 517273
 0.50 523195 523193 522192 521191 521192 523195 523195
 0.50 504176 504173 502172 500172 499172 499173 497174 498176
      500176 502177 503177 504176
 0.50 485230 485228 484228 482227 482226 482227 483229 483230
      485231 485230
 0.50 471645 471639 470634 466629 460627 457627 453628 443637
      437642 432648 424658 414670 406681 397693 380714 374726
      371734 370736 374736 404730 415722 420718 426712 434703
      445691 454681 458675 462668 468658 470651 471645
 1.00 515267 516259 515252 513245 511238 506226 499216 488209
      482207 476210 473214 469216 463216 458219 458223 462225
      466222 470218 475216 480219 485220 489226 491234 491237
      489237 484239 482238 481235 480231 477228 471229 468234
      468239 469242 472248 480256 487267 493277 497283 501285
      506284 509279 515267
 1.00 463640 461636 457635 452637 448641 438648 433652 430656
      418674 404692 398700 390709 386714 384718 385722 387722
      392720 402713 412708 418707 422704 429693 435685 444676
      451669 455664 457658 461649 463644 463640
 1.50 512255 511246 509238 505231 501223 497218 494218 492222
      493231 497239 501246 504252 506256 510258 512255
 1.50 505281 506276 506271 503262 499255 495249 491242 488241
      485243 483246 484251 487259 490265 495272 498279 501282
      505281
 1.50 486213 486211 485209 484209 483208 481208 479210 478210
      478213 479214 480216 482216 483216 485215 485214 486213
 1.50 480246 480244 480241 480240 480239 479236 479235 478233
      478232 476231 475231 473231 473232 471233 470236 471238
      472240 472241 473243 474244 474245 476246 477246 479246
      480246
 1.50 448653 446650 442651 436655 431660 427666 423673 418679
      417682 420681 422679 427678 434677 438671 443664 446658
      448653
 2.00 503275 503269 501264 499260 497255 494251 492248 490246
      488246 488254 489259 491263 493267 496270 499275 501277
      503275
 2.00 507248 506242 507240 505235 502231 500227 498223 496222
      494225 496231 498235 500240 503244 505247 507248
 2.00 478241 479238 478235 477235 476234 474234 473234 472236
      473239 475241 476243 478241

$$





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