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U.S. Week-2 Hazards Outlook - Made May 06, 2024 | About the Hazards Outlook
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| Composite Map Day 8-14 |
Experimental Probabilistic Outlooks |
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Valid Tuesday May 14, 2024 to Monday May 20, 2024
US Hazards OutlookNWS Climate Prediction Center College Park MD
300 PM EDT May 06 2024
Synopsis: Mid-level high pressure over the West Coast and mostly zonal flow over the contiguous U.S. (CONUS) results in a relatively tranquil period of weather for week-2. At the outset of week-2 a stalled frontal boundary over the Gulf Coast leads to the potential for heavy precipitation for portions of the Southeast U.S.
Hazards
- Slight risk for heavy precipitation for portions of the Southeast U.S., Tue-Thu, May 14-16.
For Thursday May 09 - Monday May 13: WPC Days 3-7 U.S. Hazards
For Tuesday May 14 - Monday May 20: At the outset of week-2 ensemble models favor moderate ridging (troughing) over the West Coast (Great Lakes) as depicted by 500-hPa height anomalies. The GEFS favors a much deeper trough over the East with the axis centered over the Appalachians, while the ECMWF features a much shallower trough over the Great Plains. Model solutions dampen both features over the course of week-2, with weak positive height anomalies and mostly zonal flow over the contiguous U.S. (CONUS) by the end of the forecast period.
While there are significant differences among model solutions in the timing and location, there is good consensus between various models with regard to the potential for heavy precipitation. Both the GEFS and ECMWF Probabilistic Extremes Tools (PETs) indicate at least a 20% probability of 3-day accumulated precipitation exceeding the 85th percentile and 1 inch for portions of the Southeast U.S for May 14-16. The ECMWF is especially bullish, with much wider coverage of the area indicated for 1 inch total and over 2 inches possible for portions of the Louisiana coast east to the Big Bend of Florida. There are some indications that heavy rainfall may persist beyond May 16, but model solutions diverge even more so, thus the hazard posted does not extend further into week-2. Although much of this area highlighted for a risk for heavy precipitation has been in a rain deficit and soils are becoming parched, most of the precipitation is anticipated to be able to infiltrate into the soil column due to soils in the area being sandy. Therefore a potential flooding hazard is not issued at this time, although localized ponding and urban flash flooding is possible.
In Alaska, as we move into the middle of May snowmelt season is underway and frozen rivers are beginning to break up. This leads to the potential for river flooding related to ice-jams. We continue to monitor the situation but currently there are no indications of impending major river break-ups or serious threat of ice-jamming so no flooding-related hazards are posted at this time.
Forecaster: Danny Barandiaran
$$ Please consult local NWS Forecast Offices for short range forecasts and region-specific information.
Resources
Week-2 Probabilistic Extremes Tool
GFS Ensemble Forecasts