####018003255#### FGUS71 KOKX 291410 ESFOKX WINTER/SPRING FLOOD POTENTIAL OUTLOOK NATIONAL WEATHER SERVICE NEW YORK NY 910 AM EST Thu Feb 29 2024 ...WINTER FLOOD POTENTIAL OUTLOOK... This is the fifth Winter/Spring Flood Potential Outlook in a series of routine Winter/Spring Flood Potential statements intended to provide insight into the likelihood of river flooding (not flash flooding) over the Lower Hudson River Valley, Northeast New Jersey, Southern Connecticut, New York City and Long Island over the next two weeks. This outlook is based on current assessment of Hydro-Meteorological factors which contribute to river flooding. These factors include recent precipitation, soil moisture, snow cover and snow water equivalent, river ice, stream flow and future weather conditions. This outlook does not address the severity of any future river flooding. The latest climate prediction center 6 to 10 day outlook valid from March 5th through the 9th suggests near above normal temperatures and above normal precipitation across the Hydrologic Service Area. The 8 to 14 day outlook valid from March 7th through the 13th suggests above normal temperatures and above normal precipitation across the Hydrologic Service Area. Heavy rainfall is the primary factor which leads to river flooding. It is important to note that heavy rainfall can rapidly cause river flooding any time of the year, even when overall river flooding potential is considered low or below normal. Current flooding - None. Precipitation - Precipitation departures from normal across the Hydrologic Service Area for the last 60 days were anywhere between 1 to 3 inches above normal across the entire Hydrologic Service Area. Snow Conditions – Below normal. There is currently no snow on the ground across the Hydrologic Service Area. River flows - Across the local Hydrologic Service Area, rivers and streams are running normal to above normal. Real-Time Water data can be found by visiting the USGS at www.usgs.gov/water. Soil moisture – Above normal. Soil moisture and drought related data and charts can be seen at https://www.cpc.ncep.noaa.gov /products/analysis_monitoring/regional_monitoring/palmer.gif and www.drought.gov. Reservoir conditions - Reservoir levels across the New York City water supply system were 4 percent above normal. Reservoir levels across the combined 13 Northeast New Jersey reservoirs were 12 percent above normal. Summary - During the two-week outlook period ending on March 14th expect temperatures and precipitation to be above normal across the Hydrologic Service Area. Flood potential during the next two weeks ending on March 14th will be normal. For more information on the threat for river flooding please visit: www.weather.gov/erh/mmefs For complete weather information, visit our web site at: water.weather.gov/ahps2/index.php?wfo=okx You can follow us on Facebook at: www.facebook.com/NWSNewYorkNY You can follow us on Twitter at: @NWSNewYorkNY The next Winter Flood Potential Outlook will be issued by this office in two weeks, on March 14th, 2024. ####018009343#### FGUS73 KMQT 291413 ESFMQT MIC013-053-061-071-103-131-291502- Probabilistic Hydrologic Outlook National Weather Service Marquette MI 912 AM EST Thu Feb 29 2024 ...2024 SPRING FLOOD AND WATER RESOURCES OUTLOOK... This Spring Flood and Water Resources Outlook is for the rivers in western and east-central Upper Michigan. ...Flood Outlook Highlights... The overall flood risk this spring is much below-normal across all of Upper Michigan. The primary factors contributing to a below- normal flood risk are significantly below normal snowpack and a lack of river ice. ...Flood Terminology... The term minor flooding is used to indicate minimal or no property damage. However, some public inconvenience is possible. The term moderate flooding is used to indicate some inundations of structures and roads near streams. Some evacuations of people and/or transfer of property to higher elevations may be needed. The term major flooding is used to indicate extensive inundation of structure and roads. Significant evacuations of people and/or transfer of property to higher elevations will be needed. ...Probabilistic Outlook... The chance of minor flooding is less than 20% at all of the Upper Michigan forecast locations except Witch Lake (30%) along the Michigamme River and Alston (34%) along the Sturgeon River. The chance of moderate flooding is 5% or less at all of the Upper Michigan forecast locations except Witch Lake (17%) along the Sturgeon River. ...Past Precipitation... Precipitation last Fall was below normal across the area and this dry pattern has continued through the end of February. ...River Conditions... Streamflow across Upper Michigan was near to below-normal and persistently warm temperatures combined with episodes of snowmelt has removed most of the river ice. ...Soil Moisture and Frost Depths... Soil moisture is below-normal across Upper Michigan due to persistently warm and dry conditions since last fall. Frost depth in Negaunee Township was 3 inches on Feb 27th and hasn't changed much since mid-January when the seasonal snowpack was established. ...Snow Cover and Liquid Water Content... Current snow water equivalent values are 0-25% of normal across all of Upper Michigan except the Michigamme Highlands and the northern Keweenaw Peninsula where SWE values were 25-50% of normal. Even though the U.P. winter is far from over, snowpack is at near- to record-low values and there aren't any major storm systems in the forecast at this time. ...River Ice Conditions... Much above-normal temperatures this winter limited ice formation and episodes of snowmelt cleared out what formed on rivers across Upper Michigan. Despite the recent cold snap, above-normal temperatures are forecast to continue into spring suggesting much below-normal potential for ice jams and associated flooding. ...Weather Outlook... The single biggest factor affecting spring flood risks are the weather conditions during the period of snow melt. A slow snow melt with little or no rainfall would elinimate this years flood risks. On the other hand, a rapid warmup accompanied by heavy rain substantially increases flood risks for portions of Upper Michigan with a few inches of lingering snow water equivalent. At this time, the Climate Prediction Center's probabilistic forecast is for 33-50% chance of below normal precipitation and above-normal temperatures continuing through March. The current threat for springtime flooding is much below-normal, but much of the Spring Flooding Outlook hinges on weather conditions over the next 4 to 8 weeks. ...Definitions... In Table 1 below...the current (CS) and historical (HS) or normal probabilities of exceeding minor...moderate...and major flood stages are listed for the valid time period. CS values indicate the probability of reaching a flood category based on current conditions. HS values indicate the probability of reaching a flood category based on historical or normal conditions. When the value of CS is more than HS, the probability of exceeding that level is higher than normal. When the value of CS is less than HS...the probability of exceeding that level is lower than normal. ...Table 1--Probabilities for minor...moderate and major flooding... Valid Period: 03/04/2024 - 06/02/2024 : Current and Historical : Chances of Exceeding : Flood Categories : as a Percentage (%) Categorical : Flood Stages (FT) : Minor Moderate Major Location Minor Mod Major : CS HS CS HS CS HS -------- ----- ----- ----- : --- --- --- --- --- --- :Michigamme River Witch Lake 9.0 10.0 12.0 : <5 30 <5 17 <5 6 :Paint River Crystal Falls (Pa 7.0 8.0 9.5 : <5 18 <5 5 <5 <5 :Black River Bessemer 10.0 12.0 14.0 : <5 11 <5 <5 <5 <5 :Ontonagon River Rockland 25.0 26.0 28.0 : <5 <5 <5 <5 <5 <5 :Sturgeon River Sidnaw 12.0 15.0 17.0 : <5 <5 <5 <5 <5 <5 Alston 8.0 11.0 14.0 : <5 34 <5 <5 <5 <5 :Chocolay River Harvey 10.0 11.5 13.0 : <5 <5 <5 <5 <5 <5 :East Branch Escanaba River Gwinn 7.0 9.0 12.0 : <5 6 <5 <5 <5 <5 :Middle Branch Escanaba River Humboldt 6.5 8.0 9.0 : <5 13 <5 <5 <5 <5 Legend CS = Conditional Simulation (Current Outlook) HS = Historical Simulation FT = Feet In Table 2 below, the 95 through 5 percent columns indicate the probability of exceeding the listed stage levels (FT) for the valid time period. ...Table 2--Exceedance Probabilities... Chance of Exceeding Stages at Specific Locations Valid Period: 03/04/2024 - 06/02/2024 Location 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Michigamme River Witch Lake 4.1 4.3 4.8 5.3 6.1 7.1 8.1 :Paint River Crystal Falls (Pa 3.2 3.4 3.7 4.1 4.7 5.4 5.6 :Black River Bessemer 3.5 3.7 4.1 4.7 6.0 7.9 8.4 :Ontonagon River Rockland 8.3 8.5 9.5 10.8 13.3 15.2 16.2 :Sturgeon River Sidnaw 5.5 5.6 5.7 6.2 6.5 7.2 7.5 Alston 5.3 5.4 5.6 6.2 6.8 7.7 7.9 :Chocolay River Harvey 3.6 3.8 4.0 4.6 5.4 6.1 7.4 :East Branch Escanaba River Gwinn 2.4 2.7 3.1 3.5 4.0 4.9 5.3 :Middle Branch Escanaba River Humboldt 3.3 3.4 4.1 4.6 4.9 5.5 5.9 In Table 3 below, the 95 through 5 percent columns indicate the probability of falling below the listed stage levels (FT) for the valid time period. ...Table 3--Nonexceedance Probabilities... Chance of Falling Below Stages at Specific Locations Valid Period: 03/04/2024 - 06/02/2024 Location 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Michigamme River Witch Lake 3.4 3.4 3.2 3.1 3.0 2.9 2.8 :Paint River Crystal Falls (Pa 2.5 2.5 2.4 2.3 2.2 2.2 2.1 :Black River Bessemer 2.5 2.5 2.4 2.3 2.2 2.2 2.1 :Ontonagon River Rockland 6.1 6.0 5.8 5.7 5.5 5.4 5.4 :Sturgeon River Sidnaw 4.4 4.4 4.3 4.2 4.2 4.1 4.0 Alston 4.4 4.3 4.2 4.1 4.0 4.0 3.9 :Chocolay River Harvey 2.9 2.8 2.8 2.8 2.8 2.8 2.7 :East Branch Escanaba River Gwinn 1.0 1.0 0.9 0.8 0.7 0.7 0.7 :Middle Branch Escanaba River Humboldt 2.2 2.1 2.1 2.0 1.9 1.9 1.9 These long-range probabilistic outlooks contain forecast values that are calculated using multiple season scenarios from 30 or more years of climatological data, including current conditions of the river, soil moisture, snow cover, and 30 to 90 day long-range outlooks of temperature and precipitation. By providing a range of probabilities, the level of risk associated with long-range planning decisions can be determined. These probabilistic forecasts are part of the National Weather Service's Advanced Hydrologic Prediction Service. Visit our web site weather.gov/mqt for more weather and water information. The next outlook will be issued March 14, 2024. $$