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COLUMBIA - GRAND COULEE DAM
(
GCDW1
)
Forecasts for Water Year
2026
Official Water Supply
ESP with 10 Days QPF
Ensemble:
2026-09-25
Issued:
2026-09-25
Hide Forecast
Forecast
Period
Forecasts Are in KAF
30 Year
Average
(1991-2020)
90 %
50 %
%
Average
10 %
APR-SEP
56211
56211
91
56211
61483
APR-JUL
49083
49083
93
49083
52774
APR-AUG
53374
53374
92
53374
58186
JAN-SEP
69089
69089
98
69089
70457
JAN-JUL
61961
61961
100
61961
61749
OCT-SEP
79648
79648
101
79648
78842
Experimental Water Supply
HEFS with 15 days EQPF
Ensemble:
2026-09-25
Issued:
2026-09-25
Hide Forecast
APR-SEP
56233
56287
92
56372
61483
APR-JUL
49083
49083
93
49083
52774
APR-AUG
53374
53374
92
53374
58186
JAN-SEP
69112
69166
98
69251
70457
JAN-JUL
61961
61961
100
61961
61749
OCT-SEP
79670
79724
101
79809
78842
Reference
ESP with 0 Days QPF
Ensemble:
2026-09-25
Issued:
2026-09-25
Hide Forecast
APR-SEP
56194
56226
91
56309
61483
APR-JUL
49083
49083
93
49083
52774
APR-AUG
53374
53374
92
53374
58186
JAN-SEP
69073
69105
98
69187
70457
JAN-JUL
61961
61961
100
61961
61749
OCT-SEP
79631
79663
101
79746
78842
Move the mouse over the desired "Forecast Period" to display a graph.
ESP10, 231, 299, 355, 408, 434, 70, , 74
ESP10, 226, 294, 350, 403, 429, 72, , 76
ESP10, 229, 303, 354, 405, 434, 74, , 78
ESP10, 227, 306, 352, 403, 432, 75, , 79
ESP10, 226, 306, 349, 400, 429, 77, , 81
ESP10, 224, 303, 348, 399, 431, 79, , 83
ESP10, 230, 304, 349, 400, 438, 81, , 85
ESP10, 233, 305, 354, 401, 439, 83, , 87
ESP10, 234, 306, 356, 402, 440, 85, , 89
ESP10, 234, 305, 354, 400, 439, 87, , 91
ESP10, 237, 309, 357, 401, 439, 88, , 92
ESP10, 236, 310, 358, 403, 439, 90, , 94
ESP10, 229, 303, 351, 396, 435, 92, , 96
ESP10, 231, 305, 355, 398, 437, 94, , 98
ESP10, 233, 304, 353, 395, 437, 96, , 100
ESP10, 221, 293, 339, 385, 428, 98, , 102
ESP10, 211, 284, 331, 380, 418, 100, , 104
ESP10, 221, 295, 345, 392, 429, 101, , 105
ESP10, 221, 294, 347, 392, 432, 103, , 107
ESP10, 221, 294, 349, 398, 435, 105, , 109
ESP10, 210, 285, 345, 388, 426, 107, , 111
ESP10, 208, 287, 343, 389, 424, 109, , 113
ESP10, 202, 288, 337, 387, 424, 111, , 115
ESP10, 210, 298, 347, 395, 432, 113, , 117
ESP10, 214, 307, 353, 399, 435, 114, , 118
ESP10, 219, 318, 357, 407, 440, 116, , 120
ESP10, 221, 316, 357, 406, 441, 118, , 122
ESP10, 223, 318, 357, 407, 441, 120, , 124
ESP10, 213, 309, 349, 398, 432, 122, , 126
ESP10, 198, 294, 337, 390, 421, 124, , 128
ESP10, 199, 295, 341, 392, 427, 126, , 130
ESP10, 203, 298, 344, 396, 433, 127, , 131
ESP10, 203, 295, 342, 392, 433, 129, , 133
ESP10, 214, 306, 351, 400, 441, 131, , 135
ESP10, 222, 309, 352, 400, 442, 133, , 137
ESP10, 222, 309, 352, 400, 440, 135, , 139
ESP10, 223, 308, 353, 397, 441, 137, , 141
ESP10, 216, 298, 348, 388, 433, 139, , 143
ESP10, 224, 303, 355, 393, 439, 140, , 144
ESP10, 222, 303, 358, 392, 439, 142, , 146
ESP10, 227, 304, 360, 390, 439, 144, , 148
ESP10, 229, 308, 358, 395, 436, 146, , 150
ESP10, 239, 316, 366, 404, 443, 148, , 152
ESP10, 251, 321, 372, 404, 448, 150, , 154
ESP10, 243, 314, 363, 395, 438, 152, , 156
ESP10, 252, 319, 368, 400, 444, 153, , 157
ESP10, 244, 311, 360, 393, 441, 155, , 159
ESP10, 252, 316, 366, 397, 449, 157, , 161
ESP10, 247, 309, 362, 394, 445, 159, , 163
ESP10, 250, 310, 364, 394, 448, 161, , 165
ESP10, 253, 312, 365, 397, 450, 163, , 167
ESP10, 254, 317, 362, 397, 447, 165, , 169
ESP10, 252, 317, 364, 394, 443, 166, , 170
ESP10, 261, 327, 374, 405, 450, 168, , 172
ESP10, 256, 321, 368, 403, 446, 170, , 174
ESP10, 259, 320, 365, 402, 447, 172, , 176
ESP10, 257, 315, 360, 398, 443, 174, , 178
ESP10, 258, 314, 360, 401, 442, 176, , 180
ESP10, 258, 317, 366, 407, 442, 178, , 182
ESP10, 250, 304, 353, 398, 433, 179, , 183
ESP10, 239, 295, 342, 389, 424, 181, , 185
ESP10, 243, 298, 346, 390, 428, 183, , 187
ESP10, 238, 292, 340, 382, 421, 185, , 189
ESP10, 221, 273, 320, 364, 410, 187, , 191
ESP10, 223, 276, 326, 368, 415, 189, , 193
ESP10, 219, 272, 323, 363, 412, 190, , 194
ESP10, 227, 280, 334, 370, 420, 192, , 196
ESP10, 216, 264, 320, 356, 407, 194, , 198
ESP10, 189, 239, 292, 329, 384, 196, , 200
ESP10, 181, 232, 285, 320, 376, 198, , 202
ESP10, 179, 238, 286, 319, 377, 200, , 204
ESP10, 186, 250, 292, 327, 387, 202, , 206
ESP10, 187, 251, 296, 331, 392, 203, , 207
ESP10, 181, 242, 289, 323, 384, 205, , 209
ESP10, 187, 239, 294, 322, 383, 207, , 211
ESP10, 190, 239, 297, 324, 386, 209, , 213
ESP10, 192, 240, 304, 325, 388, 211, , 215
ESP10, 190, 242, 302, 324, 385, 213, , 217
ESP10, 182, 235, 293, 318, 377, 215, , 219
ESP10, 186, 233, 286, 314, 373, 216, , 220
ESP10, 199, 241, 291, 321, 379, 218, , 222
ESP10, 204, 241, 291, 319, 379, 220, , 224
ESP10, 216, 256, 301, 328, 390, 222, , 226
ESP10, 222, 258, 302, 332, 393, 224, , 228
ESP10, 217, 251, 297, 330, 389, 226, , 230
ESP10, 214, 248, 295, 332, 387, 228, , 232
ESP10, 219, 249, 299, 333, 388, 229, , 233
ESP10, 225, 255, 301, 334, 396, 231, , 235
ESP10, 222, 256, 298, 333, 395, 233, , 237
ESP10, 225, 260, 302, 335, 396, 235, , 239
ESP10, 232, 267, 310, 341, 398, 237, , 241
ESP10, 231, 272, 307, 337, 394, 239, , 243
ESP10, 225, 266, 304, 331, 392, 241, , 245
ESP10, 226, 267, 307, 332, 395, 242, , 246
ESP10, 217, 262, 300, 325, 389, 244, , 248
ESP10, 215, 268, 300, 324, 390, 246, , 250
ESP10, 215, 266, 303, 325, 390, 248, , 252
ESP10, 214, 267, 299, 327, 387, 250, , 254
ESP10, 217, 268, 297, 327, 385, 252, , 256
ESP10, 220, 263, 293, 328, 381, 254, , 258
ESP10, 218, 260, 292, 330, 377, 255, , 259
ESP10, 219, 259, 294, 332, 376, 257, , 261
ESP10, 218, 257, 294, 333, 373, 259, , 263
ESP10, 215, 260, 295, 330, 370, 261, , 265
ESP10, 218, 261, 295, 329, 371, 263, , 267
ESP10, 219, 264, 297, 327, 370, 265, , 269
ESP10, 218, 269, 296, 326, 370, 267, , 271
ESP10, 219, 271, 300, 328, 370, 268, , 272
ESP10, 220, 272, 300, 327, 372, 270, , 274
ESP10, 231, 282, 309, 334, 380, 272, , 276
ESP10, 239, 287, 312, 339, 381, 274, , 278
ESP10, 243, 294, 319, 343, 387, 276, , 280
ESP10, 243, 297, 320, 344, 387, 278, , 282
ESP10, 247, 299, 327, 348, 391, 280, , 284
ESP10, 246, 299, 326, 349, 391, 281, , 285
ESP10, 244, 295, 320, 345, 385, 283, , 287
ESP10, 247, 300, 325, 349, 388, 285, , 289
ESP10, 248, 304, 325, 352, 389, 287, , 291
ESP10, 253, 306, 325, 352, 392, 289, , 293
ESP10, 252, 310, 325, 353, 394, 291, , 295
ESP10, 252, 308, 326, 353, 393, 293, , 297
ESP10, 244, 298, 317, 344, 386, 294, , 298
ESP10, 238, 290, 310, 338, 379, 296, , 300
ESP10, 249, 293, 314, 342, 382, 298, , 302
ESP10, 257, 295, 315, 341, 381, 300, , 304
ESP10, 254, 293, 315, 339, 379, 302, , 306
ESP10, 252, 290, 312, 335, 375, 304, , 308
ESP10, 261, 300, 318, 344, 383, 306, , 310
ESP10, 263, 297, 317, 342, 379, 307, , 311
ESP10, 260, 295, 316, 341, 376, 309, , 313
ESP10, 262, 300, 319, 344, 376, 311, , 315
ESP10, 264, 304, 324, 345, 375, 313, , 317
ESP10, 259, 298, 319, 339, 369, 315, , 319
ESP10, 264, 300, 322, 343, 372, 317, , 321
ESP10, 261, 300, 321, 343, 368, 319, , 323
ESP10, 248, 288, 306, 331, 355, 320, , 324
ESP10, 249, 288, 306, 333, 354, 322, , 326
ESP10, 255, 294, 315, 339, 361, 324, , 328
ESP10, 245, 282, 306, 328, 350, 326, , 330
ESP10, 257, 290, 314, 335, 360, 328, , 332
ESP10, 252, 283, 308, 329, 358, 330, , 334
ESP10, 261, 291, 314, 334, 363, 332, , 336
ESP10, 258, 287, 311, 331, 360, 333, , 337
ESP10, 265, 292, 316, 337, 366, 335, , 339
ESP10, 269, 293, 317, 340, 365, 337, , 341
ESP10, 271, 295, 319, 342, 368, 339, , 343
ESP10, 271, 297, 322, 342, 368, 341, , 345
ESP10, 266, 294, 315, 336, 362, 343, , 347
ESP10, 264, 291, 310, 330, 356, 345, , 349
ESP10, 260, 283, 303, 322, 347, 346, , 350
ESP10, 263, 285, 306, 322, 346, 348, , 352
ESP10, 260, 281, 304, 320, 342, 350, , 354
ESP10, 253, 275, 298, 311, 334, 352, , 356
ESP10, 247, 269, 295, 306, 329, 354, , 358
ESP10, 242, 266, 289, 303, 324, 356, , 360
ESP10, 244, 269, 287, 304, 323, 358, , 362
ESP10, 233, 261, 277, 292, 312, 359, , 363
ESP10, 237, 264, 278, 293, 315, 361, , 365
ESP10, 221, 247, 261, 279, 302, 363, , 367
ESP10, 236, 261, 273, 292, 313, 365, , 369
ESP10, 235, 262, 273, 294, 313, 367, , 371
ESP10, 229, 257, 269, 289, 308, 369, , 373
ESP10, 226, 253, 264, 287, 302, 371, , 375
ESP10, 235, 260, 270, 293, 310, 372, , 376
ESP10, 230, 257, 266, 288, 307, 374, , 378
ESP10, 226, 252, 261, 282, 303, 376, , 380
ESP10, 224, 247, 258, 276, 300, 378, , 382
ESP10, 227, 249, 260, 278, 302, 380, , 384
ESP10, 223, 245, 260, 278, 299, 382, , 386
ESP10, 225, 245, 260, 279, 301, 384, , 388
ESP10, 227, 243, 260, 276, 298, 385, , 389
ESP10, 237, 249, 265, 278, 303, 387, , 391
ESP10, 238, 250, 266, 277, 302, 389, , 393
ESP10, 228, 241, 258, 271, 294, 391, , 395
ESP10, 225, 238, 256, 268, 291, 393, , 397
ESP10, 227, 243, 262, 276, 296, 395, , 399
ESP10, 227, 244, 262, 278, 296, 397, , 401
ESP10, 229, 247, 266, 284, 300, 398, , 402
ESP10, 232, 255, 270, 290, 303, 400, , 404
ESP10, 237, 258, 274, 293, 307, 402, , 406
ESP10, 244, 264, 281, 300, 314, 404, , 408
ESP10, 246, 270, 281, 301, 315, 406, , 410
ESP10, 245, 269, 279, 298, 313, 408, , 412
ESP10, 248, 274, 290, 303, 319, 409, , 413
ESP10, 248, 273, 292, 307, 319, 411, , 415
ESP10, 244, 269, 289, 304, 318, 413, , 417
ESP10, 243, 269, 288, 304, 317, 415, , 419
ESP10, 245, 275, 292, 307, 320, 417, , 421
ESP10, 244, 273, 290, 307, 319, 419, , 423
ESP10, 240, 267, 283, 299, 311, 421, , 425
ESP10, 235, 263, 280, 296, 307, 422, , 426
ESP10, 234, 262, 279, 296, 306, 424, , 428
ESP10, 239, 266, 286, 302, 313, 426, , 430
ESP10, 243, 269, 288, 303, 315, 428, , 432
ESP10, 243, 272, 283, 300, 310, 430, , 434
ESP10, 251, 283, 290, 307, 318, 432, , 436
ESP10, 251, 279, 287, 304, 315, 434, , 438
ESP10, 255, 282, 289, 308, 320, 435, , 439
ESP10, 251, 276, 289, 303, 316, 437, , 441
ESP10, 253, 278, 290, 306, 317, 439, , 443
ESP10, 255, 280, 293, 309, 320, 441, , 445
ESP10, 256, 282, 296, 311, 322, 443, , 447
ESP10, 257, 282, 298, 314, 323, 445, , 449
ESP10, 265, 291, 308, 322, 334, 447, , 451
ESP10, 263, 289, 306, 320, 333, 448, , 452
ESP10, 265, 290, 306, 322, 334, 450, , 454
ESP10, 264, 295, 306, 320, 335, 452, , 456
ESP10, 263, 294, 304, 317, 332, 454, , 458
ESP10, 265, 297, 308, 320, 333, 456, , 460
ESP10, 263, 298, 308, 319, 332, 458, , 462
ESP10, 264, 299, 309, 319, 332, 460, , 464
ESP10, 271, 303, 314, 327, 337, 461, , 465
ESP10, 274, 308, 319, 330, 341, 463, , 467
ESP10, 277, 309, 321, 334, 342, 465, , 469
ESP10, 278, 307, 320, 333, 341, 467, , 471
ESP10, 279, 305, 320, 332, 338, 469, , 473
ESP10, 283, 306, 320, 334, 338, 471, , 475
ESP10, 282, 305, 320, 333, 338, 473, , 477
ESP10, 283, 303, 320, 333, 340, 474, , 478
ESP10, 284, 302, 319, 332, 340, 476, , 480
ESP10, 286, 303, 320, 332, 339, 478, , 482
ESP10, 285, 303, 317, 331, 336, 480, , 484
ESP10, 282, 301, 314, 329, 334, 482, , 486
ESP10, 284, 302, 318, 328, 336, 484, , 488
ESP10, 282, 299, 315, 326, 334, 486, , 490
ESP10, 287, 299, 318, 327, 336, 487, , 491
ESP10, 287, 297, 317, 327, 335, 489, , 493
ESP10, 288, 300, 320, 329, 336, 491, , 495
ESP10, 291, 305, 322, 331, 340, 493, , 497
ESP10, 295, 308, 326, 336, 344, 495, , 499
ESP10, 290, 304, 321, 330, 341, 497, , 501
ESP10, 288, 302, 318, 327, 337, 499, , 503
ESP10, 292, 306, 319, 326, 336, 500, , 504
ESP10, 289, 304, 316, 323, 332, 502, , 506
ESP10, 290, 306, 316, 325, 333, 504, , 508
ESP10, 285, 301, 313, 320, 329, 506, , 510
ESP10, 285, 298, 311, 320, 327, 508, , 512
ESP10, 288, 302, 313, 322, 328, 510, , 514
ESP10, 292, 305, 315, 324, 332, 512, , 516
ESP10, 284, 298, 308, 317, 324, 513, , 517
ESP10, 291, 300, 312, 321, 327, 515, , 519
ESP10, 289, 298, 311, 319, 327, 517, , 521
ESP10, 290, 298, 310, 319, 328, 519, , 523
ESP10, 293, 301, 312, 325, 331, 521, , 525
ESP10, 294, 300, 309, 323, 330, 523, , 527
ESP10, 294, 303, 311, 322, 331, 525, , 529
ESP10, 301, 310, 315, 329, 335, 526, , 530
ESP10, 304, 313, 319, 331, 339, 528, , 532
ESP10, 305, 316, 320, 333, 340, 530, , 534
ESP10, 302, 314, 321, 332, 337, 532, , 536
ESP10, 311, 323, 331, 340, 345, 534, , 538
ESP10, 311, 323, 333, 341, 345, 536, , 540
ESP10, 319, 329, 338, 347, 352, 538, , 542
ESP10, 320, 326, 337, 346, 349, 539, , 543
ESP10, 321, 328, 337, 345, 349, 541, , 545
ESP10, 323, 329, 338, 347, 350, 543, , 547
ESP10, 323, 332, 339, 348, 351, 545, , 549
ESP10, 321, 329, 338, 345, 349, 547, , 551
ESP10, 321, 329, 339, 345, 349, 549, , 553
ESP10, 325, 334, 342, 349, 352, 551, , 555
ESP10, 326, 336, 345, 351, 354, 552, , 556
ESP10, 324, 335, 343, 349, 353, 554, , 558
ESP10, 325, 337, 345, 351, 354, 556, , 560
ESP10, 321, 333, 341, 347, 353, 558, , 562
ESP10, 332, 342, 350, 355, 362, 560, , 564
ESP10, 332, 342, 349, 355, 361, 562, , 566
ESP10, 333, 343, 349, 355, 362, 564, , 568
ESP10, 328, 337, 344, 350, 356, 565, , 569
ESP10, 328, 338, 346, 349, 355, 567, , 571
ESP10, 326, 336, 344, 346, 353, 569, , 573
ESP10, 330, 340, 348, 351, 356, 571, , 575
ESP10, 335, 342, 351, 353, 359, 573, , 577
ESP10, 333, 340, 348, 352, 356, 575, , 579
ESP10, 335, 340, 348, 353, 356, 577, , 581
ESP10, 334, 339, 348, 353, 355, 578, , 582
ESP10, 338, 343, 351, 356, 358, 580, , 584
ESP10, 345, 349, 356, 359, 362, 582, , 586
ESP10, 346, 349, 356, 359, 361, 584, , 588
ESP10, 346, 350, 356, 359, 361, 586, , 590
ESP10, 346, 350, 355, 359, 361, 588, , 592
ESP10, 347, 351, 357, 360, 361, 590, , 594
ESP10, 347, 352, 356, 360, 361, 591, , 595
ESP10, 346, 351, 355, 359, 361, 593, , 597
ESP10, 345, 350, 354, 358, 359, 595, , 599
ESP10, 344, 350, 354, 357, 358, 597, , 601
ESP10, 346, 352, 355, 359, 360, 599, , 603
ESP10, 345, 352, 356, 358, 360, 601, , 605
ESP10, 346, 352, 356, 358, 360, 603, , 607
ESP10, 347, 352, 356, 358, 360, 604, , 608
ESP10, 347, 353, 356, 358, 361, 606, , 610
ESP10, 346, 353, 356, 358, 361, 608, , 612
ESP10, 347, 352, 356, 358, 360, 610, , 614
ESP10, 347, 352, 356, 358, 360, 612, , 616
ESP10, 347, 352, 356, 358, 360, 614, , 618
ESP10, 348, 352, 356, 358, 360, 616, , 620
ESP10, 349, 353, 357, 358, 360, 617, , 621
ESP10, 349, 353, 357, 359, 361, 619, , 623
ESP10, 350, 353, 357, 359, 361, 621, , 625
ESP10, 350, 354, 357, 359, 360, 623, , 627
ESP10, 352, 356, 358, 361, 362, 625, , 629
ESP10, 351, 356, 358, 360, 362, 627, , 631
ESP10, 351, 355, 358, 360, 361, 628, , 632
ESP10, 352, 356, 358, 360, 361, 630, , 634
ESP10, 351, 356, 358, 360, 361, 632, , 636
ESP10, 352, 356, 359, 360, 361, 634, , 638
ESP10, 355, 357, 360, 361, 362, 636, , 640
ESP10, 354, 356, 359, 360, 361, 638, , 642
ESP10, 355, 357, 359, 360, 361, 640, , 644
ESP10, 354, 357, 359, 360, 361, 641, , 645
ESP10, 356, 358, 360, 361, 362, 643, , 647
ESP10, 354, 357, 359, 360, 361, 645, , 649
ESP10, 354, 357, 359, 360, 361, 647, , 651
ESP10, 353, 357, 359, 360, 361, 649, , 653
ESP10, 353, 357, 359, 360, 361, 651, , 655
ESP10, 355, 358, 359, 360, 362, 653, , 657
ESP10, 357, 360, 362, 362, 364, 654, , 658
ESP10, 356, 359, 360, 361, 363, 656, , 660
ESP10, 356, 359, 360, 361, 363, 658, , 662
ESP10, 354, 357, 359, 360, 361, 660, , 664
ESP10, 355, 358, 359, 360, 361, 662, , 666
ESP10, 356, 358, 359, 360, 361, 664, , 668
ESP10, 356, 359, 360, 360, 361, 666, , 670
ESP10, 356, 358, 360, 360, 361, 667, , 671
ESP10, 357, 359, 360, 360, 361, 669, , 673
ESP10, 357, 359, 360, 361, 362, 671, , 675
ESP10, 358, 360, 361, 361, 362, 673, , 677
ESP10, 356, 359, 360, 361, 362, 675, , 679
ESP10, 356, 359, 360, 361, 361, 677, , 681
ESP10, 356, 359, 360, 360, 361, 679, , 683
ESP10, 355, 357, 359, 360, 360, 680, , 684
ESP10, 356, 358, 359, 360, 360, 682, , 686
ESP10, 356, 358, 359, 359, 360, 684, , 688
ESP10, 355, 357, 358, 359, 360, 686, , 690
ESP10, 355, 357, 358, 358, 359, 688, , 692
ESP10, 355, 357, 358, 358, 359, 690, , 694
ESP10, 357, 358, 359, 359, 360, 692, , 696
ESP10, 357, 358, 359, 359, 360, 693, , 697
ESP10, 355, 356, 357, 358, 358, 695, , 699
ESP10, 357, 358, 358, 359, 359, 697, , 701
ESP10, 357, 358, 359, 359, 360, 699, , 703
ESP10, 358, 358, 359, 359, 359, 701, , 705
ESP10, 358, 358, 359, 359, 359, 703, , 707
ESP10, 358, 358, 359, 359, 359, 705, , 709
ESP10, 357, 357, 357, 358, 358, 706, , 710
ESP10, 356, 357, 357, 358, 358, 708, , 712
ESP10, 356, 357, 357, 358, 358, 710, , 714
ESP10, 356, 357, 357, 358, 358, 712, , 716
ESP10, 357, 357, 358, 358, 358, 714, , 718
ESP10, 356, 356, 356, 357, 357, 716, , 720
ESP10, 356, 356, 357, 357, 357, 718, , 722
ESP10, 356, 356, 357, 357, 357, 719, , 723
ESP10, 357, 357, 357, 357, 357, 721, , 725
ESP10, 357, 357, 357, 357, 357, 723, , 727
ESP10, 357, 357, 357, 357, 357, 725, , 729
ESP10, 357, 357, 357, 357, 357, 727, , 731
ESP10, 357, 357, 357, 357, 357, 729, , 733
ESP10, 357, 357, 357, 357, 357, 731, , 735
ESP10, 357, 357, 357, 357, 357, 732, , 736
ESP10, 357, 357, 357, 357, 357, 734, , 738
Max Scale
Scale To Data
Scale To Last 45 Days
Show Min/Max Ensemble Volume
Show Tooltips Help
Overlay
ESP10
HEFS
ESP0
Data Files
/chpsesp/ensemble/watersupply/GCDW1W_SQIN.ESPF10.csv
GCDW1W_SQIN.ESPF0.csv|2026-09-25
GCDW1W_SQIN.ESPF10.csv|2026-09-25
GCDW1W_SQIN.ESPFM.csv|2026-09-25
APR-SEP
COLUMBIA - GRAND COULEE DAM
(
GCDW1
)
Forecasts for Water Year
2027
Official Water Supply
ESP with 10 Days QPF
Ensemble:
2026-09-25
Issued:
2026-09-25
Hide Forecast
Forecast
Period
Forecasts Are in KAF
30 Year
Average
(1991-2020)
90 %
50 %
%
Average
10 %
APR-SEP
48696
59627
97
76228
61483
APR-JUL
39656
49039
93
64346
52774
APR-AUG
45347
55699
96
72098
58186
JAN-SEP
54675
66258
94
85192
70457
JAN-JUL
46798
56742
92
73220
61749
OCT-SEP
61575
74363
94
93076
78842
Move the mouse over the desired "Forecast Period" to display a graph.
Max Scale
Scale To Data
Scale To Last 45 Days
Show Min/Max Ensemble Volume
Show Tooltips Help
Overlay
ESP10
Data Files
/chpsesp/ensemble/watersupply/GCDW1W_SQIN.ESPF10.csv
GCDW1W_SQIN.ESPF0.csv|2026-09-25
GCDW1W_SQIN.ESPF10.csv|2026-09-25
GCDW1W_SQIN.ESPFM.csv|2026-09-25
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ESP10,ESPM,ESP0
ESP10,ESPM,ESP0
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