QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
253 AM EDT SAT MAY 25 2013


PRELIM DAY 1 QPF DISCUSSION
VALID MAY 25/1200 UTC THRU MAY 26/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...


...NORTHEASTERN STATES...

THE SLOW MOVING CLOSED H5 LOW AND ACCOMPANYING SURFACE LOW ARE
STILL EXPECTED TO BRING SIGNIFICANT RAINFALL AMOUNTS TO NEW
ENGLAND..AND ESPECIALLY INTERIOR AREAS..AS THE VERY STRONG
DEFORMATION AXIS TO THE NORTH OF THE SYSTEM CONTINUES TO BE THE
FOCUS FOR THE PRECIPITATION.  THE LATEST MODEL MASS FIELD
FORECASTS AND QPFS ARE IN GOOD AGREEMENT ON THIS SCENARIO..SO
CONFIDENCE RATHER HIGH FOR THIS MANUAL FORECAST.  EXPECT
WIDESPREAD 0.50-1.00+ INCH RAINFALL TOTALS MUCH OF NEW ENGLAND AS
PER THE MODEL GUIDANCE..AND WOULDN'T BE AT ALL SURPRISED TO SEE
SOME WET SNOWS OCCUR IN THE HIGHEST ELEVATIONS FROM NORTHERN NY
STATE THRU NORTHERN VT AND NH INTO NORTHERN ME..MAINLY ON SATURDAY
NIGHT.


...NORTHERN HI PLAINS SOUTHEASTWARD INTO THE MIDWEST...

A COUPLE OF STREAMS OF H5 S/WV ENERGY IMPACTING THE NORTHERN HI
PLAINS AND MIDWEST THIS PERIOD..ALONG WITH EITHER A MOIST
SOUTHEASTERLY LOW LEVEL JET INTO THE HI PLAINS OR A
SOUTH-SOUTHWESTERLY LOW LEVEL JET AND WARM FRONT AFFECTING THE
MIDWEST..SHOULD LEAD TO 2 AREAS OF MORE
ENHANCED CONVECTION/RAINFALL AMOUNTS.  IN THE NORTHERN HI
PLAINS..H5 S/WV ENERGY INITIALLY IN THE NORTHERN GREAT BASIN WILL
LIFT NORTHEASTWARD INTO THE NORTHERN HI PLAINS LATER SATURDAY
AFTERNOON AND NIGHT AND TAP A SOMEWHAT STRENGTHENING SOUTHEASTERLY
LOW LEVEL JET BRINGING IN HIGHER PWS TO SUPPORT THE MORE ORGANIZED
CONVECTION FROM EASTERN MT INTO ESPECIALLY WESTERN ND.  EXCEPT FOR
THE UKMET HIRES MODEL WHICH MAY BE A LITTLE TOO HEAVY
QPF-WISE..THE REMAINDER OF THE GUIDANCE IS IN DECENT AGREEMENT ON
AT LEAST A SMALL AREA OF 0.50-1.00+ INCH RAINFALL AMOUNTS..SO
FOLLOWED THIS IDEA.  DOWN IN THE MIDWEST AND ESPECIALLY IA..AN
INITIAL ROUND OF CONVECTION EARLY IN THE PERIOD SHOULD BE FOLLOWED
LATER SATURDAY EVENING AND NIGHT BY ANOTHER MORE SIGNIFICANT ROUND
OF CONVECTION..AS MORE SOUTHERN STREAM H5 S/WV ENERGY NOW VICINITY
OF THE CENTRAL GREAT BASIN COMBINES WITH SOME INCREASE IN
SOUTH-SOUTHWESTERLY LOW LEVEL JET AND A WARM FRONT LIFTING TOWARDS
THE REGION TO SUPPORT THIS ACTIVITY.  THE GFS QPF LOOKS UNDERDONE
HERE..WITH THE NAM NOT QUITE AS BAD..AND IN GENERAL LEANED TOWARDS
NON-NCEP GLOBAL MODEL SOLUTIONS AND SOME OF THE HIGHER RES
MODELS..ALL OF WHICH HAD HEAVIER RAINFALL AMOUNTS.  COMBINATION OF
THE 2 EVENTS OVER IA SHOULD LEAD TO AREAL AVERAGE 1-2 INCH
RAINFALL TOTALS..WITH ISOLATED AMOUNTS AT OR ABOVE 3 INCHES
POSSIBLE.


...TX...

THE FORECAST HERE REMAINS QUITE A BIT MORE CHALLENGING..GIVEN
CONTINUED MODEL QPF DIFFERENCES AND 
A PERSISTENT REGIME OF BROAD MOIST SOUTHERLY LOW LEVEL FLOW INTO
THE AREA BUT WITH A LACK OF ANY SIGNIFICANT SURFACE BOUNDARY TO
FOCUS AND CONVECTION.  IN ADDITION..ALTHOUGH A MID LEVEL SHEAR
AXIS HAS PUSHED THRU CENTRAL TX AT THIS TIME..SEVERAL MODELS SHOW
SOME CONVECTIVE REDEVLOPMENT TO THE WEST OF THIS AXIS..IN THE
BETTER AXES OF SLIGHTLY STRONGER LOW LEVEL JET AND HIGHER PWS..AND
IN FACT THE MOST RECENT RADAR IS SHOWING SOME OF THIS IS NOW
OCCURRING BETWEEN AUS AND SAT.  SO..MANUAL PROG INCORPORATED THE
IDEA OF SOME ENHANCED CONVECTION THIS PERIOD TO THE EAST OF THE
SHEAR AXIS OVER NORTHCENTRAL/NORTHEASTERN TX..BUT WITH THE
LIKELIHOOD ALSO OF SOME CONVECTION DEVELOPING IN THE BETTER LOW
LEVEL JET/HIGHER MOISTURE AXES BACK OVER SOUTHCENTRAL TX.  MANUAL
PROG MOST CLOSELY RESEMBLES THE NAM AND NON-NCEP MODEL QPF
SOLUTIONS..WITH THE GFS NOT PICKING UP THE ACTIVITY AS WELL WEST
OF THE SHEAR AXIS.  DIDN'T GO HEAVY WITH EITHER AREA AS CONFIDENCE
NOT THAT HIGH..BUT GIVEN SOME PWS GREATER THAN 1.75 INCHES
AVAILABLE..ISOLATED HEAVY RAINS CERTAINLY A POSSIBILITY.


...PAC NW...

THE NEXT EASTERN PAC H5 S/WV WILL ROTATE TOWARDS THE PAC NW
COAST..AND ESPECIALLY INTO COASTAL OR..LATE IN THE
PERIOD..UNDERNEATH THE VORTEX SPINNING ABOUT IN PLACE OVER
SOUTHWESTERN CANADA. 
INCREASINGLY FAVORABLE LARGE SCALE LIFT WITH THIS APPROACHING S/WV
AND SOME PERSISTENT WEAK LOW LEVEL ONSHORE FLOW SHOULD LEAD TO
SOME ENHANCED RAINFALL TOTALS MUCH OF WESTERN OR..WITH MANUAL QPF
LEANING TOWARDS SLIGHTLY HEAVIER NCEP QPF SOLUTIONS.

TERRY

GRAPHICS AVAILABLE ON THE WEB AT www.wpc.ncep.noaa.gov/qpf/qpf2.shtml

24HR QP VT 26/12Z
 0.01 513651 509667 504682 499696 492710 485722 479729 476734
      466744 463748 460751 454755 441763 435762 430760 426760
      420758 417759 414758 409755 401750 401743 399735 398730
      397722 400716 403713 405709 408707 414699 417695 424691
      427688 427683 423675 415658 413651 417645 423639 421635
      418633 415629 413623
 0.01 491599 490601 489605 487607 485610 482612 480613 479613
      475612 472611 470607 469607 467605 465602 463599 461595
      459592 457589 456589 454587 452585 450584
 0.01 540202 539191 536179 533167 526159 512150 506146 503149
      501154 496161 490166 486170 488173 489177 488180 485187
      483196 477205 474206 470210 461210 455214 447216 438216
      431220 426223 426231 418233 413233 410236 408240 408245
      413252 417255 420259 424261 429262 436261 444260 460256
      463254 467254 470251 476252 481247 480235 482233 484235
      485238 489247 493258 494268 499275 502277 505273 518273
 0.01 508045 509031 508026 507023 502017 496010 490005 486001
      479996 474993 471990 468990 463985 455969 444938 434909
      427897 421886 410874 403867 396867 391871 389878 389885
      390896 393910 395918 396922 394924 389928 385931 383935
      384938 386943 389946 393952 397957 400966 402975 405981
      411987 413989 415995 419999 424006 425013 428019 429024
      432029 435034 437047 438052 440056 441060 444064 450066
      454072 457080 458091 457097 455099 453093 451093 445096
      441096 440100 441109 446113 449122 451126 450132 448139
      447150 449159 452160 455156 456146 456143 455139 455127
      458120 458114 461110 465108 469108 476107 479103 480099
      482095 483091 484084 486081 488075 491071 499063 508045
 0.01 377028 377021 372020 368018 362018 354019 351020 348022
      340024 337024 335027 329028 323032 319034 315032 310033
      307039 309042 313046 321046 325046 330048 344049 361047
      363047 366044 369040 377028
 0.01 372964 372960 369958 362955 354955 348952 337945 330941
      323939 318937 310936 303936 297938 295941 295944 299950
      302953 302959 302963 300966 294970 287972 274979 270984
      269988 269993 269001 271007 275011 278013 282015 288018
      292022 297022 300024 307024 320019 326015 330013 335012
      341008 347004 351999 352995 354991 356983 358980 362978
      370972 372964
 0.01 270050 269046 266044 262041 259039 256036 253033 249032
      244032 240034 241039 244041 247043 251045 255047 259048
      263049 266051 270050
 0.25 507638 507644 504655 498674 490688 487699 485706 481713
      476722 466735 460741 452747 443750 436750 431749 426747
      420743 415737 413730 416720 420713 424707 435694 438690
      439686 440679 438674 436669 434664 433658 441645 440627
      442621 447620 452623 457627 464629 469630 475633 481634
      485630 487626 493619 498616
 0.25 434602 435602 439603 443604 443599 440597
 0.25 531209 533205 533200 532192 529185 527180 524177 522173
      516169 513171 510175 510179 512187 514194 516199 518205
      520211 523214 528213 531209
 0.25 519259 519254 518252 516248 516247 514243 512246 512251
      512253 514257 514258 517260 519259
 0.25 491054 492046 493036 491028 490023 487019 481015 478015
      473016 469017 464019 461022 458025 455024 449024 449031
      453039 459048 460055 461064 464068 468070 476066 482064
      485062 488059 491054
 0.25 459241 459236 455234 452231 451226 452221 448219 442219
      438221 436223 432232 428236 422239 419243 420246 424249
      428251 435250 442248 450246 456244 459241
 0.25 439959 438947 436939 434928 430917 427909 423902 419896
      414889 408887 404889 402893 402897 402907 402924 402935
      404946 406954 407959 410963 414968 422970 428973 434973
      436971 438967 439959
 0.25 347965 343958 337953 331950 327950 322952 318967 312973
      305978 296978 291979 287981 282985 281989 279994 283002
      286004 291004 310002 320000 323999 326995 328987 332981
      337975 339972 344971 347968 347965
 0.50 503632 501627 499625 496625 492629 489636 486641 482644
      461635 455634 453633 452636 450639 449644 448652 444666
      447675 447683 444690 441697 432711 425723 424727 424732
      426737 429741 434742 440743 446743 452741 458735 463730
      473717 477711 480703 481684 482678 485670 487666 491664
      496661 499654 501646 502637 503632
 0.50 486046 487041 487037 487028 484023 481021 478021 473025
      470028 467034 466038 466047 468052 470057 476058 482055
      485050 486046
 0.50 446237 446236 443235 441235 440235 437235 434237 434238
      430239 428239 427241 424242 427244 430244 432245 436244
      439244 440243 442242 445241 445240 446237
 0.50 445224 445223 442223 445225 445224
 0.50 435952 432936 428920 425912 422907 415897 411895 408897
      407903 405919 406935 409949 411957 415962 420964 427965
      432965 433964 435960 435952
 0.50 335967 337963 336960 334957 328956 326958 326965 324970
      322972 318976 318980 320981 325979 328976 330973 333969
      335967
 0.50 316990 315986 312983 306983 300983 298982 294983 289984
      287987 286990 287992 290994 293996 299997 304997 310995
      315993 316990
 1.00 466706 464700 463697 460697 456706 452708 449709 446712
      441720 439724 439730 442733 446735 453733 460725 464719
      466715 468710 466706
 1.00 479042 481037 479033 479032 478033 476035 474038 473041
      473042 473043 476045 479043 479042
 1.00 430957 431950 431944 428933 425926 421915 417908 415907
      413909 411918 410926 410931 411937 413944 417951 420955
      423954 429957 430957
 1.50 426946 427941 426937 425934 424930 423927 422926 421923
      419920 416921 414925 414927 414929 414930 415932 417936
      418939 419939 421943 422944 425946 426946