####018004337#### FGUS71 KPHI 291738 ESFPHI DEC001-003-005-MDC011-015-029-035-041-NJC001-005-007-009-011-015- 019-021-023-025-027-029-033-035-037-041-PAC011-017-025-029-045- 077-089-091-095-101-010545- Winter/Spring Flood Potential Outlook National Weather Service Mount Holly NJ 1238 PM EST Thu Feb 29 2024 Winter/Spring Flood Potential Outlook...Number 5 This is the fifth in a series of annual Flood Potential Statements that provides an assessment of how ready or primed our forecast area is for river flooding. This outlook covers the middle/lower Delaware, Lehigh, Schuylkill, Passaic and Raritan River basins. It will provide information on flood threat contributors such as recent precipitation, soil moisture, snow cover and its water equivalent, river ice conditions, streamflow, future precipitation and others. This assessment is valid between February 29 - March 14, 2024. In the Mid-Atlantic region, 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 year, even when the overall river flood potential is considered to be low. This outlook does not discuss flash flooding, nor does it discuss any extent or severity of flooding. In the Mount Holly, New Jersey Hydrologic Service Area (HSA), the overall river flood potential is normal. Note - For the headwaters of the Delaware River, see the statement (FGUS71 KBGM ESFBGM) from our Binghamton (BGM) New York office. CURRENT FLOODING - None. There is currently no river flooding occurring within our service area. RECENT PRECIPITATION - Below normal. Between 1.0 and 2.0 inches of liquid have been recorded over the last 30 days across the entire HSA. Precipitation departure maps can be found at www.weather.gov/marfc (under the Water Supply tab). SNOW COVER - There is very little snow, if any, north of the I-80 corridor. Any remaining snow water equivalents (SWE) are running between 0.10 inch and 0.20 inches. Depth and basin-average water equivalent estimates can be found at www.weather.gov/marfc (under the Seasonal Interest tab) or www.nohrsc.noaa.gov (under the National Analysis tab). RIVER ICE - We have no reports of river ice across our area of responsibility at this time. STREAMFLOW - Normal to slightly above normal. Real time water data is available from the United States Geological Survey (USGS) by visiting https://dashboard.waterdata.usgs.gov. SOIL MOISTURE - Normal to above normal. Soil moisture monitoring charts (Long Term Palmer Drought Severity Index) from NOAA's Climate Prediction Center can be found at the following websites... www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_ monitoring/palmer.gif as well as www.drought.gov. GROUND WATER - USGS monitoring wells indicate that current ground water levels across the region vary and are running below normal to above normal. Additonal information can be found at https://dashboard.waterdata.usgs.gov. RESERVOIR CONDITIONS - Water supply and flood control reservoirs in the area are mainly running normal. FUTURE WEATHER CONDITIONS - Surface high pressure builds over the region today and will influence the region through Friday. Weak low pressure brings precipitation to the region Friday night through Saturday night. Weak high pressure may return for Sunday and Monday, but the pattern becomes fairly uncertain, stagnant, and potentially unsettled Sunday into midweek. The 8 to 14 day outlook calls for above normal temperatures and precipitation. SUMMARY - Taking all of the included variables into consideration, the overall river flood potential is normal across the forecast area. For complete weather information, visit our website at: www.weather.gov/phi && Overall Flood Potential...Normal Current Flooding...None Recent Precipitation...Below normal Snow cover...Below normal north, normal south River Ice...Below normal north, normal south Streamflow...Normal to slightly above normal Soil Moisture...Normal to above normal Ground Water...Below normal to above normal Reservoir Conditions...Normal $$ Kruzdlo ####018014848#### FGUS73 KBIS 291739 ESFBIS NDC001-007-011-015-021-025-029-031-033-037-041-043-045-047-051-053- 055-057-059-061-065-083-085-087-089-093-103-105-021745- Probabilistic Hydrologic Outlook National Weather Service Bismarck ND 1139 AM CST Thu Feb 29 2024 ...SPRING FLOOD AND WATER RESOURCES OUTLOOK... This Spring Flood and Water Resources Outlook is for the James and Missouri basins of North Dakota, covering the period of 2 March through 31 May, 2024. This is the second in a three-part Spring Flood and Water Resources Outlook series. The following message has four sections. The first provides some text on the highlights of this outlook and conditions affecting the local hydrology. The second section gives the current and historical risks of flooding as determined by the Ensemble Streamflow Forecast model of the National Weather Service. The third section gives the current probabilities for reaching flood stage at the listed forecast locations. And finally, the fourth section covers the risk of the river sites falling below the listed stages. ...Flood Outlook Highlights... Despite a few inches of snow scattered around since the first Spring FLood Outlook, the overall risk of widespread flooding remains very low going into spring. Nonetheless, as the region moves into the month of March, spring rains still represent the lion's share of the risk reflected in the tables. March is the transition month for the region from normal daytime highs of below freezing temperatures during the first week, to average daytime highs well above freezing by the last week of the month. Thus, the risks below are more due to spring rains on well frozen ground than they are for actual runoff from melting snow. Similarly, the flood risk is also tied directly to the soil conditions. The surface of the ground across much of North Dakota remains wet and frozen. Once the ground begins to thaw, the risk of flooding will fall even further as a thawed surface to the ground will allow more infiltration of rain and meltwater than the current frozen ground. Perhaps the greater risk going into spring is the existing long-term trend of below normal precipitation. If this trend continues, increased and expanded drought designations are a real concern given the lack of snow across North Dakota. ...Missouri and Yellowstone Rivers... In western North Dakota the Missouri and Yellowstone rivers above Lake Sakakawea are back down to normal water levels for this time of year despite having recently experienced modest runoff. The overall snowpack on the plains and headwaters area of Montana continues to trend well below normal for this time of year, and remains in contention for the lowest observed Snow-Water Equivalent (SWE) going into spring for the Missouri and Yellowstone rivers in the past 30 years. However, an ice jam has formed in the Bismarck/Mandan area of the Missouri River below Garrison Dam. As of 29 February, it is currently just below the defined flood stage. Nonetheless, it has already created minor impacts and created plenty of angst over its potential to pose a real problem. This ice jam should resolve in the coming few days as warmer weather once again envelopes the area, but until then it does pose a risk for damaging high water. ...Snowpack Conditions... Overall snowpack across the Missouri and James River basins of North Dakota is well below normal for this time of year with generally a trace to well under an inch of Snow-Water Equivalent on the ground. ...Current Drought Conditions... A steady, but slow expansion of D0 (Unusually Dry) drought is likely to continue across much of the Missouri and James River basins in response to the growing snow deficit. However, actual impacts are not yet being felt as the region is still in the winter season. A continuation of the dry pattern in place will increase drought concerns going into spring as the ground thaws and the region enters its growing season. ...Reservoirs and Natural Wetlands... With only a few exceptions all man-made reservoirs, livestock dams, and natural wetlands are at, or below, their normal water levels for this time of year. Those few exceptions are generally in the areas with well frozen ground where runoff from a nominal snowpack exceeded expectations. ...Soil Conditions... Soil moisture values across the Missouri and James basins are generally near normal going down to near 40 inches (100 cm), but the ground surface is much wetter than normal due to early winter rain and melting snow. This has created a wet and frozen ground surface that is near impermeable to infiltration of future rain or meltwater. The importance of this hard, frozen ground cannot be overstated. Any early spring rain that falls before this soil thaws will create an unusually high amount of runoff for a given rainfall total. It is expected that these soils will largely remain impermeable until some time around the middle of March. ...Weather Outlook... The Climate Prediction Center 6-10 day outlooks favor near normal in the western part of the state to warmer than normal temperatures for central and eastern North Dakota. Precipitation for the same period is expected to be below normal in the northwestern two-thirds of the state and slightly above normal in the southeastern one-third of the state. The weeks 3-4 outlooks favor above normal temperatures state-wide, with an equal chances designation for above normal, near normal, or below normal precipitation for all but the southeastern corner which has a slight favoring for above normal precipitation. Overall, North Dakota is favored for an above normal temperature outcome during March, with an equal chance for above normal, near normal, or below normal precipitation. The longer 3-month outlook for March, April and May combined favors above normal temperatures with an equal chance for above normal, near normal, or below normal precipitation. In general, this is consistent with the expectation that the El Nino affected winter season will fade into an ENSO neutral pattern by late spring to early summer. ...Ice Conditions... All small lakes and wetlands are covered with ice of highly variable, but somewhat less than normal thickness for this time of year. Recent warm weather has also been softening ice on the small lakes, especially near the shoreline. Some small rivers in western North Dakota lost much of their ice during a warm spell that included a modest amount of runoff. This suggests that the risk of ice jams is likely below normal on many of the western North Dakota streams. ...Spring Flood Outlook Release Dates... The NWS has set the release dates for the Spring Flood and Water Resources Outlook series as follows: First issuance: February 15, 2024 First update: February 29, 2024 Final update: March 14, 2024 After the official Spring Flood and Water Resource Outlook series, the NWS will return to its routine, monthly issuance of Flood and Water Resource Outlooks on March 28, 2024 unless the spring melt is already in full swing. In Table 1 below, the current (CS) and historical (HS) or normal probabilities of exceeding minor...moderate...and major flood stage 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 greater 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: 03/02/2024 - 05/31/2024 : 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 -------- ----- ----- ----- : --- --- --- --- --- --- :Pipestem Pingree 11.0 13.0 15.0 : <5 12 <5 <5 <5 <5 :James River Grace City 12.0 14.0 15.0 : <5 15 <5 9 <5 8 LaMoure 14.0 16.0 18.0 : <5 17 <5 8 <5 <5 :Missouri River Williston 22.0 24.0 26.0 : 5 31 <5 10 <5 8 :Cannonball River Regent 22.0 24.0 26.0 : <5 <5 <5 <5 <5 <5 :Cedar Creek Raleigh 12.0 14.0 16.0 : <5 9 <5 5 <5 <5 :Cannonball River Breien 10.0 20.0 23.0 : 10 58 <5 <5 <5 <5 :Beaver Creek Linton 12.0 14.0 16.0 : <5 45 <5 31 <5 13 :Little Muddy River Williston 10.0 12.0 14.0 : 6 69 <5 35 <5 10 :Little Missouri River Marmarth 18.0 23.0 30.0 : <5 6 <5 <5 <5 <5 Medora 15.0 18.0 20.0 : <5 18 <5 8 <5 6 Watford City 20.0 24.0 30.0 : <5 14 <5 5 <5 <5 :Knife River Manning 15.0 17.0 20.0 : <5 24 <5 <5 <5 <5 :Spring Creek Zap 14.0 18.0 20.0 : 9 29 6 17 5 11 :Knife River Hazen 21.0 24.0 25.0 : 11 43 8 25 <5 23 :Heart River Mandan 27.0 33.0 38.0 : <5 23 <5 <5 <5 <5 :Apple Creek Menoken 15.0 16.0 17.0 : 24 58 16 53 <5 34 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: 03/02/2024 - 05/31/2024 Location 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Pipestem Pingree 5.2 5.2 5.2 5.2 5.7 7.8 8.7 :James River Grace City 4.1 4.1 4.1 4.1 5.0 5.9 6.4 LaMoure 7.4 7.4 7.4 7.5 8.3 9.2 10.4 :Missouri River Williston 16.8 17.3 18.0 18.6 19.3 20.4 21.8 :Cannonball River Regent 5.2 5.2 5.6 6.4 7.9 8.8 9.7 :Cedar Creek Raleigh 1.0 1.1 2.2 3.2 4.4 5.3 5.7 :Cannonball River Breien 2.8 3.1 3.9 5.9 8.3 10.0 10.7 :Beaver Creek Linton 4.3 4.4 4.5 5.4 6.4 10.1 11.5 :Little Muddy River Williston 4.3 4.3 4.8 5.6 7.7 9.0 10.5 :Little Missouri River Marmarth 1.1 1.1 1.1 1.3 3.7 7.0 10.6 Medora 1.5 1.5 1.5 2.3 3.9 7.2 11.0 Watford City 7.1 7.1 7.1 7.8 9.7 11.9 14.7 :Knife River Manning 6.4 6.4 6.4 7.6 9.3 10.8 14.1 :Spring Creek Zap 4.8 4.9 5.3 6.6 8.1 12.4 19.3 :Knife River Hazen 0.6 0.9 3.9 7.8 12.2 22.9 24.4 :Heart River Mandan 11.2 12.3 13.1 15.3 19.2 21.4 25.3 :Apple Creek Menoken 4.7 5.1 5.8 7.7 15.0 16.5 16.6 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: 03/02/2024 - 05/31/2024 LOCATION 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Pipestem Pingree 5.1 5.1 5.1 5.1 5.1 5.1 5.1 :James River Grace City 4.1 4.1 4.1 4.1 4.1 4.1 4.1 LaMoure 7.1 7.1 7.1 7.1 7.1 7.1 7.1 :Missouri River :Cannonball River Regent 5.0 5.0 5.0 5.0 5.0 5.0 5.0 :Cedar Creek Raleigh 0.6 0.4 0.3 0.3 0.3 0.3 0.3 :Cannonball River Breien 2.2 2.2 2.2 2.1 2.1 2.0 2.0 :Beaver Creek Linton 4.3 4.2 4.2 4.2 4.2 4.2 4.2 :Little Muddy River Williston 4.3 4.3 4.3 4.3 4.3 4.3 4.3 :Little Missouri River Marmarth 1.1 1.1 1.1 1.0 1.0 0.9 0.9 Medora 1.5 1.5 1.4 1.4 1.3 1.3 1.3 Watford City 7.1 7.1 7.1 7.0 7.0 6.8 6.8 :Knife River Manning 6.4 6.4 6.3 6.3 6.2 6.2 6.2 :Spring Creek Zap 4.8 4.8 4.8 4.8 4.8 4.8 4.8 :Knife River Hazen 0.6 0.6 0.5 0.5 0.4 0.3 0.3 :Heart River Mandan 11.0 10.9 10.9 10.9 10.8 10.7 10.7 :Apple Creek Menoken 3.9 3.9 3.9 3.8 3.7 3.5 3.4 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/bis for more weather and water information. The next outlook will be issued on 14 March. $$ Schlag