000 FGUS71 KGYX 181914 ESFGYX MEC001-005-007-011-013-015-017-023-025-027-031-NHC001-003-005-007- 009-011-013-015-017-019-191915- Winter/Spring Flood Potential Outlook National Weather Service Gray ME 314 PM EDT Thu Apr 18 2024 ...FINAL SPRING FLOOD POTENTIAL OUTLOOK FOR NEW HAMPSHIRE AND WESTERN MAINE... The flood potential outlook for New Hampshire and Western Maine is above normal through late April despite little to no residual snowpack. Ground conditions are exceptionally wet across the region with limited runoff storage. The risk will remain elevated until the seasonal green-up is fully underway, which has already started in parts of southern New Hampshire and Maine. This is the ninth and final issuance in a series of regularly scheduled flood potential outlooks highlighting the flood potential during the next two-week period. This issuance represents the flood risk through the rest of April for New Hampshire and western Maine. ...OBSERVED SNOW DEPTH AND WATER EQUIVALENT... The snowpack has melted out for all but the higher elevations and north facing slopes of the mountains. The snow depth goes from bare ground in the valleys to 1 to 3 feet above 2,000 feet. The snowpack in these regions are ripe with high densities, and a snow water equivalent of 2 to 5 inches. ...SOIL MOISTURE AND WATER SUPPLY CONDITIONS... Exceptionally moist ground conditions, high streamflows, and high reservoir and lake levels suggest very limited storage for storm runoff. Soils in areas without snow have thawed with water release showing up in groundwater wells. The groundwater levels remain much above normal with additional recharge over the last few weeks as thawing spread northward. Streamflow levels courtesy of the USGS were running above to well above normal due to a recent rain on snow event. Runoff storage capacity remained below normal for the time of year with high lake levels for most of the region. Kennebec River Basin storage in Maine was 94 percent full which was 86 percent above normal. The nearby Androscoggin River storage was 92 percent full which was 47 percent above normal. Lake Winnipesaukee...New Hampshire's largest lake...increased to 0.95 feet above normal as of 15 April 2024. The lake is at its full level despite almost continuous releases. ...RIVER AND ICE CONDITIONS... The ice threat has ended for the season. ...CLIMATOLOGY AND TEMPERATURE AND PRECIPITATION OUTLOOKS... El Nino has continued to weaken with neutral ENSO conditions expected through June. The active trend looks to shift into the central U.S., giving New England a period of drier than normal conditions through late April. The official National Weather Service 6 to 14 day Outlook for 24-30 April 2024 leans likely above normal temperatures and near normal to below normal precipitation. These conditions favor continued melt in the mountains with limited opportunities for heavy precipitation events. That being said, until green-up has begun the region will remain vulnerable to excessive runoff. ...IN CONCLUSION... Based on the above meteorological and hydrological information, the short term flood risk is above normal. The potential for rapid runoff remains elevated until the seasonal green-up is fully underway. Groundwater levels are well above normal and storage capacity for runoff is limited. The coverage of snow is limited to the higher elevations and is not expected to be sufficient to significantly contribute to mainstem river flooding. Flash flooding and small stream flooding in the mountains will remain a concern until all of the snow has melted. It is important to note that major flooding does not occur from snowmelt alone. Rainfall, how much and in how short a period of time, is the most important factor in determining the severity of flooding. This is the final issuance of the Spring Flood Outlook for the 2024 season. $$ Jamison