####018003112#### FGUS71 KBGM 151950 ESFBGM NYC007-011-015-017-023-025-053-065-067-077-097-099-101-105-107- 109-123-PAC015-069-079-103-115-127-131-202000- Winter/Spring Flood Potential Outlook National Weather Service Binghamton NY 250 PM EST Thu Feb 15 2024 ...OVERALL FLOOD RISK IS BELOW NORMAL FOR LATE FEBRUARY... This is the fourth edition of the series of regularly scheduled Hydrologic outlooks issued during the Winter to Spring transition season. This outlook is designed to provide a general overview of river flood potential (not flash flooding) across Central New York and Northeast Pennsylvania through February 29, 2024. Remember that heavy rainfall is the most important determining factor toward the development and severity of flooding in our area. ...SUMMARY... The river and lake flood potential for the NWS Binghamton hydrologic service area is below normal in the Oswego Drainage, Chemung, North Branch Susquehanna, and Upper Delaware headwaters. The risk is near normal in the Upper Main Stem Susquehanna, Lackawanna, Lackawaxen and Neversink river basins. ...CURRENT CONDITIONS AS OF FEBRUARY 15... Recent Precipitation: Below normal. Weekly departures were showing generally less than 50% of normal. Snow Cover: Below normal. Less than 2 inches across most of New York and Northeast Pennsylvania except for a swath of deeper snow pack from the southwest Catskills across the Poconos including the Neversink, Lackawaxen, Upper Delaware and North Branch Susquehanna where 4 to 10 inches exist. Snow Water Equivalent: There is up to 1 inch of liquid in the areas where significant snow cover exists with hydrologically insignificant amounts elsewhere. Streamflow + Lake levels: Above normal. River Ice: Below normal. No significant ice cover exists on area rivers. Ground State: Wetter than normal. Soil temperatures indicate that there is no significant frost or freezing in any basin. METEOROLOGICAL AND HYDROLOGIC FORECAST OUTLOOK... FUTURE WEATHER CONDITIONS: The official 6 to 14 day outlook suggests warmer than normal temperatures and above normal precipitation. Medium range meteorological models suggest warmer than normal but less than average precipitation through the period. LONG RANGE RIVER MODELING AND PROBABILITY FORECASTS: The ensemble of river forecast system guidance suggests less than a 10 percent chance of river flooding during this time period. When comparing current hydrologic forecast modeling against historical flows, the current flood risk is generally below the seasonal probability. ...IN CONCLUSION... Taking all of the included variables into consideration, the overall river flood potential is below normal for much of the service area, except near normal for portions of the major basins in Northeast Pennsylvania. If conditions change over the next two weeks, Flood Watches and Warnings will be issued as necessary. The next Outlook is scheduled for February 29, 2024. $$ JAB ####018012357#### FGUS75 KPUB 151949 ESFPUB COC003-009-011-015-021-023-025-027-041-043-055-061-065-071- 079-089-099-101-105-109-119-311800- PROBABILISTIC HYDROLOGIC OUTLOOK NATIONAL WEATHER SERVICE Pueblo CO 1250 PM MST Thu Feb 15 2024 ...SPRING FLOOD AND WATER RESOURCES OUTLOOK... This outlook is for the Arkansas River Basin in southeast Colorado and the Rio Grande Basin in south-central Colorado. This outlook is valid from February 13 to May 13, 2024. The potential for spring flooding, caused by snowmelt alone, is near normal for the Arkansas River Basin. The potential for spring flooding, caused by snowmelt alone, is below normal for the Rio Grande Basin. ...OUTLOOK FOR THE ARKANSAS RIVER BASIN... Temperatures have fluctuated between above and below normal levels since the beginning of the water year (Oct 1, 2023) with minimal to no drought conditions present throughout the Arkansas River Basin heading into the winter months. Despite a strong El Nino in effect, mountain precipitation was off to a slow start with only 68 percent of normal basin-wide snowpack snow-water-equivalent (SWE) at the end of December. January and the first half of February, however, have brought beneficial snowfall to the basin with basin-wide mountain snowpack SWE recovering to 97 percent of normal as of February 13. Mountain snowpack for the mountains along the Continental Divide of the upper Arkansas River Basin and sub-basins draining from the eastern slope of the Sangre de Cristo Mountains are trending at near normal levels for the middle of February. The potential for spring flooding due to snowmelt during the next 90 days is limited and near normal. Any snowmelt flooding that develops will most likely be minor and would only result in minimal property damage and minor public threat or incovenience. Table 1. below, shows 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: 02/13/2024 - 05/13/2024 : 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 -------- ----- ----- ----- : --- --- --- --- --- --- :Arkansas River Leadville 9.0 10.0 12.0 : <5 <5 <5 <5 <5 <5 Salida 8.0 9.0 10.0 : <5 <5 <5 <5 <5 <5 Wellsville 9.0 10.0 11.0 : <5 <5 <5 <5 <5 <5 Parkdale 9.0 10.0 11.0 : <5 <5 <5 <5 <5 <5 Canon City 10.0 12.0 14.0 : <5 <5 <5 <5 <5 <5 Portland 9.0 10.0 11.0 : <5 <5 <5 <5 <5 <5 Pueblo 8.0 9.0 11.0 : <5 <5 <5 <5 <5 <5 Avondale 7.0 8.0 9.0 : 20 8 11 <5 <5 <5 Nepesta 16.5 17.5 18.5 : 9 <5 5 <5 <5 <5 Fowler 13.5 14.0 15.0 : <5 <5 <5 <5 <5 <5 Rocky Ford 10.0 11.0 12.0 : <5 <5 <5 <5 <5 <5 La Junta 11.0 13.0 15.0 : 29 13 8 <5 <5 <5 Lamar 11.0 13.0 15.0 : <5 <5 <5 <5 <5 <5 :Fountain Creek Colorado Springs 11.5 16.0 18.0 : <5 <5 <5 <5 <5 <5 Fountain Creek ne 12.0 14.0 16.0 : <5 <5 <5 <5 <5 <5 Pinon 12.0 14.0 15.0 : <5 <5 <5 <5 <5 <5 Pueblo 10.0 12.0 13.5 : <5 <5 <5 <5 <5 <5 :St. Charles River Vineland 12.0 15.0 18.0 : <5 <5 <5 <5 <5 <5 :Purgatoire River Madrid 7.0 9.0 11.0 : <5 <5 <5 <5 <5 <5 Trinidad Lake 10.0 12.0 14.0 : <5 <5 <5 <5 <5 <5 Trinidad 11.0 12.0 13.0 : <5 <5 <5 <5 <5 <5 Las Animas 9.0 12.0 15.0 : 15 9 5 <5 <5 <5 Legend CS = Conditional Simulation (Current Outlook) HS = Historical Simulation FT = Feet The table above indicates a near normal chance for exceeding flood stage over the next 90 days. The probability of flooding in most years is very low and is considered normal for the Arkansas River Basin. This analysis is for the period ending May 13 with the normal snowmelt period occurring from late April to mid-June. Those locations where the probability of exceeding flood stage is greater than 5 percent do not show a significant difference between the current (CS) conditions and historical (HS) or normal conditions. These results are consistent with a near normal snowpack expected. Any snowmelt flooding that develops will most likely be minor and would result in minimal property damage or threat to the public and only minor inconveniences. Snowmelt flooding should not be confused with other types of flooding such as those associated with heavy rain from storms, releases from reservoirs, or extreme runoff from burn scars. This outlook does not address the potential for those types of floods. Flooding and flash flooding from heavy rainfall or burn scar runoff is always a possibility during heavy rain events. ...OUTLOOK FOR THE RIO GRANDE BASIN... The spring flood potential in the Rio Grande Basin, from snowmelt runoff alone, is below normal. Any snowmelt flooding that develops will most likely be minor and would only result in minimal property damage and minor public threat or inconvenience. Probabilities of exceeding flood stage or various flood categories such as those presented for the Arkansas River Basin are not currently available for the Rio Grande Basin. However, a qualitative assessment of the spring flood potential for the Rio Grande Basin is presented below. After a slow start to the snowpack accumulation season, snowpack conditions for the Rio Grande Basin have steadily improved over January and the first half of February with basin-wide mountain snowpack SWE at 91 percent of normal as of February 13. Snowpack conditions for sub-basins draining from the eastern San Juan Mountains, La Garita Mountains, and the west slope of the Sangre de Cristo Mountains range from near normal to slightly below normal for the middle of February. Soil moisture conditions remain below to well below normal due to widepread drought conditions in place heading into the winter months. Despite closer to normal snowpack conditions, soil moisture deficits will likely reduce the probability of excess snowmelt runoff that would cause flooding for the next 90 days.The probability of flooding in most years is very low and is considered normal for the Rio Grande Basin. Any snowmelt flooding that develops will most likely be minor and would result in minimal property damage or threat to the public and only minor inconveniences. Snowmelt flooding should not be confused with other types of flooding such as those associated with heavy rain from storms, releases from reservoirs, or extreme runoff from burn scars. This outlook does not address the potential for those types of floods. Flooding and flash flooding from heavy rainfall or burn scar runoff is always a possibility during heavy rain events. ...FLOOD ASSESSMENT QUALIFIER... The snowpack accumulation season is just past the halfway point until the snowpack typically peaks in early April for both the Arkansas River and Rio Grande Basins. March and April, however, are often the snowiest months of the accumulation season, and the current outlook for spring snowmelt flooding can change dramatically between now and when the snowmelt season typically begins in mid to late April. In addition to peak snowpack levels, meteorological conditions and snowmelt patterns can also have a substantial influence on the outlook for excess runoff and flood concerns. These flood potential assessments are also based on current conditions and projections of average temperature and precipitation for the coming months. It does not reflect any flood potential due to more extreme weather conditions. If unusually warm or wet weather conditions develop over the region during the next 90 days or during the snowmelt period, then much more severe flooding is possible. ...SUMARRY OF PAST, PRESENT AND FUTURE CONDITIONS... Temperatures this winter have fluctuated between above and below normal through December and mostly below normal temperatures were experienced throughout the state of Colorado for the month of January. So far, temperatures in February have ranged from near normal to slightly above normal across the state. Snowpack conditions for the mountains of the Arkansas River Basin have improved to near normal conditions for this time of year. Snowpack conditions for the Rio Grande Basin range between near normal and slightly below normal for this time of year. As of February 13, basin-wide mountain snowpack SWE was 97 percent of normal for the Arkansas River Basin and 91 percent of normal for the Rio Grande Basin. Precipitation for the Water Year (beginning October 1, 2023), as measured at NRCS SNOTEL stations at the higher elevations, is normal for the Arkansas River Basin and slightly below normal for the Rio Grande Basin. As of February 13, the water year-to-date precipitation was 104 percent of normal for the Arkansas River Basin and 90 percent of normal for the Rio Grande Basin. At the beginning of February, overall reservoir storage was at 107 percent of normal for the Arkansas River Basin while storage for the Rio Grande Basin was above normal at 122 percent. Soil moisture conditions remain favorable for the Arkansas River Basin coming off a wetter than normal summer and beneficial precipitation which fell during the fall and early winter. Although some recent improvement in snow accumulation has been observed, widespread drought conditions continue to persist throughout the Rio Grande Basin with the San Luis Valley being the most impacted by drier than normal soil moisture levels. The National Weather Service, Climate Prediction Center has indicated that strong El Nino conditions will likely transition fairly quickly back to La Nina conditions by the beginning of summer. Due to the expected persistence of El Nino conditions throughout the spring, however, the 3-month climate outlook for the February through April period indicates likely near normal temperatures and near to slightly above normal precipitation for south-central and southeast Colorado. ...SCHEDULE OF OUTLOOKS... This is the first of three scheduled Spring Flood and Water Resources Outlooks for 2024. Additional outlooks may be issued if conditions change significantly. Long range probabilistic outlooks for the Arkansas River Basin are issued near the second and fourth Thursdays of most months. The next probabilistic outlook will be issued on February 29. ...ADDITIONAL INFORMATION... Visit our web site at weather.gov/pub for more hydrologic information including graphs of probabilistic river outlooks. The National Weather Service Pueblo CO hydrology page can be accessed by clicking the Rivers and Lakes tab near the top of the page. $$