Quantitative Precipitation Forecast
Issued by NWS

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000
FXUS04 KWBC 291849
QPFPFD

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
248 PM EDT TUE JUL 29 2014


PRELIM DAY 1 QPF DISCUSSION
VALID JUL 30/0000 UTC THRU JUL 31/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAY 1...


...CENTRAL AND SOUTHERN ROCKIES INTO THE SOUTHERN PLAINS...

THE COMBINATION OF HIGH CONTENT MOISTURE AIR RIDING NORTH ON A LOW
LEVEL JET UP AND OVER A QUASI STATIONARY EXTENDING FROM THE
SOUTHERN ROCKIES INTO THE SOUTHERN PLAINS WILL RAISE THE SPECTER
OF HEAVY TO EXCESSIVE RAINFALL. TWO DISTINCT AREAS OF HEAVY RAIN
ARE EXPECTED. THE FIRST AREA IS ASSOCIATED WITH CONVECTIVE
CLUSTERS OVER WY AND EASTERN CO...WHICH SHOULD THEN TRACK ACROSS
THE PLAINS AFTER 30/00Z. A SECOND AREA IS EXPECTED WITH A
DEVELOPING MCS OVER SOUTHEAST CO THAT IS EXPECTED TO MOVE OVER THE
QUASI STATIONARY FRONT (ALONG THE AXIS OF BEST INSTABILITY...BOTH
SURFACE BASED AND ELEVATED) BETWEEN 30/06Z AND 30/18Z.

THE VERY WET PATTERN WILL PERSIST THROUGH THE PERIOD ACROSS THE
ROCKIES. THE 12Z ANALYSIS SHOWED PRECIPITABLE WATER VALUES BETWEEN
TWO AND THREE STANDARD DEVIATIONS ABOVE NORMAL AT BOTH SLC AND
RIW...AN INDICATION OF THE AMOUNT OF MOISTURE AVAILABLE IN THE
PLUME. IN FACT...THE LOW LEVEL MOISTURE FLUX BULLSEYE WAS LOCATED
OVER WESTERN WY. CONVECTION HAS DEVELOPED ACROSS SOUTHEAST ID AND
WESTERN WY...AS THE CLOUDINESS HAS THINNED AND MLCAPE VALUES HAVE
INCREASE.

DIVERGENCE AHEAD OF A CLOSED LOW OVER NORTHWEST NM SHOULD AID IN
SYNOPTIC SCALE ASCENT...PROMOTING GREATER COVERAGE ACROSS
NORTHEAST UT...WY INTO EASTERN CO. PRECIPITABLE WATER VALUES
BETWEEN TWO AND THREE STANDARD DEVIATIONS WILL FUEL THE FLASH
FLOOD THREAT. THE LATEST SSEO PROBABILITY OF QPF EXCEEDING THREE
HOUR FLASH FLOOD GUIDANCE VALUES PEAKS NEAR 00Z OVER WESTERN
WY...AN INDICATION OF THE HIGH MOISTURE CONTENT OF THE AIR.

THE SLIGHT RISK WAS EXPANDED TO INCLUDE SOUTHEAST ID AND WESTERN
WY TO ACCOUNT FOR THE INCREASED THREAT DUE TO THE HIGH MOISTURE
AIRMASS IN PLACE. A MODERATE RISK AREA WAS MAINTAINED FOR PORTIONS
OF SOUTHEAST WY AND NORTHEAST CO...AS THE HIGH MOISTURE CONTENT OF
THE AIR AND UPSLOPE FLOW SHOULD RESULT IN QPF VALUES GREATER THAN
2.00 INCHES IN THESE LOCATIONS. MOST OF THIS SHOULD BE ASSOCIATED
WITH CONVECTIVE CLUSTERS OR AN MCS THAT FORMS FROM THE CONVECTION
THAT FIRES ACROSS SOUTHEAST WY AND NORTHEAST CO...WHICH ROLLS OUT
INTO THE PLAINS AFTER 30/00Z. THESE QPF VALUES ARE SUPPORTED BY
THE LATEST ECMWF AND GEFS ENSEMBLE OUTPUT. GIVEN THAT THE THREE
HOUR FLASH FLOOD GUIDANCE VALUES ARE AS LOW AS 1.00 TO 1.50
INCHES...THE MODERATE RISK WAS DRAWN TO ENCOMPASS THE
ABOVEMENTIONED LOCATIONS.

AFTER 30/00Z...CONVECTION DEVELOPING IN SOUTHEAST CO IS EXPECTED
TO RIDE ALONG THE QUASI STATIONARY FRONT EXTENDING ACROSS
SOUTHWEST KS AND NORTH CENTRAL OK. MOST OF THE MODEL INSTABILITY
IS ELEVATED AS A 20 TO 30 KNOT SOUTHERLY FLOW OVERRUNS THE
BOUNDARY. THE INSTABILITY IS EXPECTED TO EXTEND ALONG THE FRONT
INTO NORTHWEST OK AND FAR NORTH TX THROUGH 30/12Z. THERE IS STILL
SOME SPREAD IN THE PLACEMENT OF THE QPF...AND THE LATEST ECMWF
ENSEMBLE AND GEFS OUTPUT SUGGEST THE POTENTIAL FOR 3 TO
4+ INCHES OF QPF. A LARGE NUMBER OF THE 12Z MODEL SUITE HAVE
PLACED QPF AMOUNTS BETWEEN 3 AND 6 INCHES ACROSS THE
ABOVEMENTIONED AREA...WITH SOME LATITUDINAL DIFFERENCES...BASED ON
THE TRACK OF THE EXPECTANT MCS. A MORE SOUTHERLY TRACK WAS USED
FOR THE QPF MAXIMUM HERE...AS THERE SHOULD NOT BE ANY CAPPING
ISSUES THIS EVENING INTO THE OVERNIGHT...AND THE SIMULATED IMAGERY
FROM THE NAM SHOWED THE MCS THAT DEVELOPS OVER SOUTHEAST CO
TRACKING ALONG THE FRONT ACROSS NORTHWEST OK AND NORTHERNMOST TX.

THE MCS SHOULD START TO WEAKEN BETWEEN 30/12Z AND 30/18Z AS THE
LOW LEVEL INFLOW WEAKENS AND THE MOISTURE PLUME DISSIPATES.
HOWEVER...THE MCV THAT DEVELOPS WITH THE MCS SHOULD PROVIDE ENOUGH
LIFT TO TAKE ADVANTAGE OF THE INSTABILITY AND MOISTURE IN PLACE TO
PRODUCE QPF INTO SOUTHEAST OK AND WESTERN AR.


...GREAT LAKES/OHIO VALLEY...

A DEEP CLOSED LOW OVER ONTARIO AND QUEBEC WILL CONTINUE TO SPIN IN
PLACE...PRODUCING A COOL CYCLONIC FLOW ACROSS THE GREAT LAKES
THROUGH 31/00Z. STEEPENING MID LEVEL LAPSE RATES SHOULD PRODUCE
MARGINAL INSTABILITY ACROSS THE GREAT LAKES THIS AFTERNOON AND
THIS EVENING...AND PRECIPITABLE WATER VALUES NEAR AN INCH SHOULD
SUPPORT SCATTERED CONVECTION ACROSS THE UPPER GREAT LAKES THIS
AFTERNOON...WHERE THE CIN IS ERASED FIRST. THE LOW TOPPED
CONVECTION SHOULD SUPPORT LOCAL 0.10 TO 0.25 INCH QPF AMOUNTS
ACROSS WI AND MI THROUGH 30/00Z. WITH THE LOSS OF DAY TIME
HEATING...THAT ACTIVITY SHOULD BECOME MORE WIDELY SCATTERED THIS
EVENING.

ACTIVITY SHOULD FIRE AGAIN WED AFTERNOON AS MID LEVEL LAPSE RATES
SUPPORT MARGINAL INSTABILITY IN AN ENVIRONMENT WITH PRECIPITABLE
WATER VALUES TOPPING OUT NEAR AN INCH. MOST OF THE ACTIVITY SHOULD
FORM ALONG A SURFACE TROUGH THAT CROSSES THE THE NORTHERN OH
VALLEY AND LOWER GREAT LAKES DURING THE AFTERNOON INTO THE EARLY
EVENING. THE GENERAL MODEL CONSENSUS WAS TO PLACE A LARGE AREA OF
0.25 TO 0.50 INCHES OF QPF ACROSS THE NORTHERN HALF OF
OH...NORTHWEST PA AND WESTERNMOST NY STATE... CLOSER TO THE BETTER
CONCENTRATION OF CONVECTION ALONG THE SURFACE TROUGH.


...GULF COAST/FL...

CONVECTION FORMING ALONG A SURFACE TROUGH AHEAD OF A COLD FRONT
DROPPING TO THE CENTRAL GULF COAST AND NORTHERN FL WILL BE THE
FOCUS FOR CONVECTION DURING THE AFTERNOON AND EVENING HOURS.
MODERATE INSTABILITY AND WEAK SHEAR SHOULD LIMIT THE CONVECTIVE
COVERAGE ALONG THE FRONT...RESULTING IN STRIPES OF 0.10 TO 0.25
INCHES OF QPF ACROSS PORTIONS OF SOUTHERNMOST LA AND PORTIONS
SOUTHEAST TX...AS WELL AS CENTRAL AND SOUTHERN FL. DUE TO THE
BETTER COVERAGE ACROSS CENTRAL FL...AN AXIS OF 0.25 TO 0.50 INCHES
OF QPF WAS PLACED HERE...AND LOCALLY HIGHER AMOUNTS ARE POSSIBLE
GIVEN THE 2.00 INCH PRECIPITABLE WATER VALUES IN PLACE.

THE FRONT SHOULD DROP FURTHER SOUTH ACROSS FL DURING WED
AFTERNOON. MODEL SOUNDINGS SHOWED MODERATE INSTABILITY IN PLACE
AHEAD OF THE SURFACE FRONT (OR SURFACE TROUGH BY THAT TIME...AS
THE FRONT WEAKENS)...AS WELL AS PRECIPITABLE WATER VALUES BETWEEN
1.75 AND 2.00 INCHES. THIS SHOULD SUPPORT AT LEAST SCATTERED
CONVECTION AHEAD OF THE FRONT ACROSS CENTRAL AND SOUTHERN FL THAT
PRODUCES STRIPES OF 0.10 TO 0.25 INCHES OF QPF.


...GREAT BASIN...

CONVECTION ACROSS THE GREAT BASIN WILL BE PREDICATED MAINLY ON THE
COMBINATION OF MOISTURE IN THE INCREASED MONSOONAL FLOW AND
MARGINAL INSTABILITY DUE IN MOST PART TO STEEPENING MID LEVEL
LAPSE RATES. ORGANIZATION MAY BE MORE DIFFICULT AS THE MID LEVEL
RIDGE REMAINS MORE OR LESS IN PLACE. THE ACTIVITY IS DEVELOPING
THIS AFTERNOON...AND SHOULD REMAIN SCATTERED BASED ON THE 0.75 TO
1.25 INCH PRECIPITABLE WATER VALUES IN PLACE. ONE HOUR FLASH FLOOD
GUIDANCE VALUES ACROSS THE GREAT BASIN ARE GENERALLY BETWEEN 0.75
AND 1.25 INCHES...SO ANY CONVECTION COULD PRODUCE THIS MUCH QPF
BASED ON THE AVAILABLE MOISTURE. HOWEVER...WITHOUT A STRONG
FOCUS...A SEE TEXT AREA SHOULD COVER THIS ACTIVITY. THE BULK OF
THE ACTIVITY SHOULD START TO WANE AFTER SUNSET... PERHAPS LASTING
UNTIL ABOUT 30/06Z.

ACTIVITY SHOULD DEVELOP IN THE SAME AREA AGAIN DURING THE
AFTERNOON CENTERED AROUND 30/18Z. SINCE THE AIRMASS DOES NOT
CHANGE MUCH...AND THE MID LEVEL RIDGING REMAINS IN PLACE...THE
CONVECTION SHOULD DEVELOP IN THE SAME PLACES THIS AFTERNOON AND
THIS EVENING. MUCH OF THE CONVECTION IS EXPECTED TO BE ROOTED TO
THE TERRAIN...WITH STRIPES OF BASIN AVERAGE QPF BETWEEN 0.10 AND
0.25 INCHES. HOWEVER...DUE TO THE HIGHER MOISTURE CONTENT OF THE
AIRMASS....LOCAL AMOUNTS OF NEAR AN INCH ARE POSSIBLE.


HAYES


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

24HR QP VT 31/00Z
 0.01 420637 422643 426646 428647 428650 428655 425662 420670
      419678 417684 412692 407700 401707 385720 378725 372731
      343757 336763 329770 324776 318782 315786 314792 315795
      317796 320797 323795 331791 338786 343783 349782 352782
      354779 357777 360776 360782 353786 348789 344793 340796
      337801 337807 338813 338819 334818 324814 317815 318812
      317809 315809 309805 306804 303805 300809 296818 287835
      280855 277863 277875 278890 281902 284914 283916 279918
      276918 273921 269923 266922 260917 259912 257908 253882
      251870 249861 246847 245836 245830 247826 247817 245804
      247790 248784 250781 252777 254773 259765 264758 274746
      281738 287732 294724 296723 297720 298715 314705 321700
      327694 357669 368659 370658 372658 373659 375658 377657
      378656 379656 380655 382655 383653 385652 387651 388649
      390648 391647 393645
 0.01 547833 547824 547815 543805 540795 536788 531779 524770
      525743 523726 517722 511721 506721 504720 485719 476719
      466721 462724 460728 457732 453735 450737 446739 443747
      439752 435754 430756 426759 410767 406769 402773 398780
      396785 394787 389794 383801 380809 383813 385819 388829
      389853 389859 391865 393874 405889 415905 417917 422924
      426931 431938 435940 438945 443945 445945 447942 447936
      445932 440928 436924 433919 429911 427902 426898 427896
      430897 435896 437892 439885 438882 433873 429866 426861
      428857 430857 437852 440849 444849 453848 456847 456844
      455838 452825 452821 453818 458820 462827 466839 468851
      471861 474870 476875 479880 481884 485889 495904 499904
      503902 509895 513889 517882 533870 542853 545844 547833
 0.01 473133 466131 464124 461122 460118 458111 457105 458099
      456084 453075 453067 450063 448062 441059 437054 434049
      429037 426030 423022 418010 412999 409987 404973 401966
      396960 393954 389948 384936 380922 374919 370915 360909
      356907 350908 343910 337912 330923 323936 321951 319952
      319958 319967 321975 323979 326985 327990 330995 331003
      326021 325026 323028 321031 318032 316034 312034 306034
      302038 300040 300044 307045 311045 311042 314039 318041
      315047 302063 296068 290071 283072 275072 267071 262067
      253061 248057 242054 238055 236057 235061 237067 241070
      246072 250075 263084 267087 272093 276096 277102 280107
      282109 285111 291113 297111 309108 315106 322107 330103
      340093 342091 341089 340081 339074 337071 341070 346069
      352073 364079 367084 369090 374096 379097 385098 388098
      390100 392104 390107 385111 382112 377111 374114 374117
      373127 373133 375139 380144 385148 392151 401159 408169
      411180 414195 417202 422204 425203 429197 429189 427182
      425177 422169 421162 419155 420145 420141 422138 426134
      431133 429139 428142 429146 432154 437159 443163 447165
      452162 456158 459153 463148 465141 466136 469135 473133
 0.01 455218 454215 452216 446214 441211 440209 436208 432210
      428216 427218 427222 434223 439222 445221 450221 455218
 0.01 463886 463878 459876 456874 454872 450872 447877 445880
      444885 446887 451887 454891 456893 460893 461888 463886
 0.01 450731 448727 444727 441726 439724 442721 443715 441716
      438719 435727 433725 432728 436729 441730 446729 450731
 0.01 440122 431118 421119 417119 413121 409122 406119 399118
      394119 397124 401131 408137 413137 416135 423130 426127
      430127 437124 440122
 0.01 432847 432845 430843 429845 428845 427848 426850 427852
      429852 430850 432847
 0.01 403202 402199 399196 398192 396188 390191 388187 385184
      384180 387178 390181 394180 396178 397173 392167 391157
      386157 384159 383162 380162 378159 375155 372154 370156
      369161 371170 369174 367176 363178 360181 360187 362190
      370194 375199 383204 390207 399207 403205 403202
 0.25 516832 516821 515812 513806 510802 507796 504788 504778
      503771 503764 501757 497746 493741 489739 479744 472745
      468747 460753 443769 440774 436778 434772 433770 431770
      428771 424771 425775 429778 429784 427787 424787 421783
      416782 413784 400804 398809 396816 396824 397831 398838
      399842 401846 404848 404852 410861 410846 410838 413834
      417830 424827 459806 472822 473832 475839 478844 480852
      482857 486861 489865 493867 500857 508849 513841 516832
 0.25 450104 450099 449097 445092 437087 431085 430082 430076
      431067 431059 427046 422037 419032 415028 405021 403019
      400018 395019 391016 389011 387999 385993 382988 380974
      377961 374948 372942 368938 362934 357932 351933 347935
      342939 338943 332953 330959 331965 337972 341985 346997
      349011 352022 354026 356032 357038 353043 348046 350052
      357060 361059 366062 375069 380068 386070 387076 389081
      393085 398087 403086 406084 409086 411084 416086 420089
      422093 426098 428101 426104 424106 424111 426112 430111
      436110 440108 446107 450104
 0.25 439148 438147 438146 437145 436146 435147 434148 434150
      436152 438151 438150 439148
 0.25 414651 408650 402651 392656 380663 369671 351685 339693
      331700 322709 315717 300736 286753 279763 273773 264794
      261801 255803 253806 254809 258813 261818 265823 268827
      271824 286806 294797 300788 306778 312767 319757 326750
      335742 346734 363720 372710 382702 391694 399687 406677
      412664 414657 414651
 0.25 411110 412106 413101 412096 412092 410090 407089 404090
      402093 402097 402102 402106 402109 404111 407113 410112
      411110
 0.25 376191 375189 373187 371188 373189 374189 376191 376191
 0.25 307089 307085 307081 303078 296076 289076 285079 279080
      276080 274083 281086 286087 291090 296092 298092 300095
      304093 307089
 0.25 271902 272894 271886 270870 268855 263852 263848 266835
      264833 262839 261843 258843 256844 255848 255856 258862
      257870 258878 260895 262900 264905 266907 269908 271902
 0.50 494774 493771 491768 488769 486770 485774 484778 483781
      482785 482789 484790 487788 489786 491783 492780 493777
      494774
 0.50 471771 465760 461759 458760 453766 444776 441781 437787
      429798 426803 424810 428814 430814 432811 436806 438803
      441802 455798 460795 463787 468773 471771
 0.50 443099 441094 438092 433092 428090 424088 424091 427095
      431099 432104 430106 433106 436102 439100 443099
 0.50 425082 425081 423080 423081 423083 425082 425082
 0.50 427065 425053 425049 423045 418036 411031 405025 402023
      400026 398027 393025 389023 387020 385009 383000 379992
      376981 371961 368949 367945 364943 358941 355941 347942
      341948 337956 336960 337962 339965 343973 346985 348993
      353013 354018 357022 361029 366037 370044 370051 373054
      381058 381062 382065 384065 393065 395067 394070 392073
      390076 392080 395084 397080 404077 415067 419070 422070
      427065
 0.50 405663 404656 399655 391660 374672 359684 343696 335702
      330708 317722 311730 306737 301744 294752 289759 284766
      279773 275782 272793 274797 276799 280800 283799 286795
      291788 297780 302774 307766 311757 317749 323744 331738
      339732 353721 368707 375701 382696 389690 396682 402673
      405663
 0.50 417802 417799 417797 416795 416797 415800 415801 414802
      415804 415805 416804 417802 417802
 0.50 407098 407096 406094 405094 404095 404098 406100 407098
 0.50 403063 402061 400061 399062 400063 402064 403063
 0.50 367054 367053 365052 363052 361052 359052 358052 356053
      357056 359057 361057 363056 365056 366055 367054
 0.50 299086 299084 298082 297082 296080 296079 294079 292079
      290080 290081 289083 290085 292086 293086 295087 297087
      299087 299086
 0.50 268808 268806 268804 267803 265804 264805 263805 261806
      261807 262807 263809 264810 265811 266811 266810 267809
      268808
 1.00 420050 418045 415040 411036 408031 404027 401034 389034
      390048 385048 381044 380045 378048 379051 383052 386053
      389052 391051 393053 395055 397055 404054 410056 415059
      418061 419058 420050
 1.00 394668 389669 384671 376676 362688 353694 346700 331712
      320727 318731 316736 319736 322735 326732 341721 357710
      372697 379692 386685 391676 394668
 1.00 381033 382027 381022 381013 376997 370981 365965 362959
      358952 354950 351951 346956 345966 348974 352991 356009
      358015 363021 373032 377034 381033
 1.50 415052 416048 415045 413043 411040 408038 407036 403037
      401037 401040 403043 404046 406048 408049 411051 413052
      415052
 1.50 382681 380678 377680 373683 369687 364691 359695 355699
      353704 357703 362699 367696 372692 376688 380684 382681
 1.50 379022 378014 376008 371994 366979 364972 361965 358960
      353958 349963 351971 353979 354987 358001 363014 372025
      374027 377026 379022
 2.00 413047 413045 412043 411043 410041 409040 408040 406039
      405040 405041 404042 405042 406044 406045 408046 409047
      410048 411048 413047
 2.00 378019 374010 370999 367987 363976 361971 358967 355968
      355976 357987 360998 364010 366014 370018 373022 377021
      378019
 3.00 368001 367999 366996 366995 364995 363996 363998 364999
      365001 365002 367003 368001
 3.00 361983 361980 359978 358980 359981 360983 361983

$$





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