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U.S. Week-2 Hazards Outlook - Made June 01, 2020 | About the Hazards Outlook
| Composite Map Day 8-14 |
Experimental Probabilistic Outlooks |
 |
Valid Tuesday June 09, 2020 to Monday June 15, 2020
US Hazards OutlookNWS Climate Prediction Center College Park MD
300 PM EDT June 01 2020
Synopsis: An active start to the tropical season is becoming more likely toward the end of Week-1 and heading into Week-2, as models favor the development of a tropical low in the Gulf of Mexico elevating the risk of heavy precipitation and high winds for the southern U.S. Mid-level high pressure forecast over the southwestern U.S. and the Southern Plains is expected to lead to anomalously warm temperatures into the middle of June.
Hazards
- Slight risk of heavy precipitation for portions of the Southern Plains, the Lower and Middle Mississippi Valley, and the Southeast, Tue-Fri, Jun 9-Jun 12.
- Moderate risk of heavy precipitation for portions of the Southern Plains, the Lower Mississippi Valley, and the Southeast, Tue-Thu, Jun 9-Jun 11.
- Slight risk of high winds for portions of the Southern Plains, the Lower Mississippi and Tennessee Valleys, and the Southeast, Tue-Thu, Jun 9-Jun 11.
- Slight risk of high winds for portions of the Central and Northern Plains, Tue-Sat, Jun 9-Jun 13.
For Thursday June 04 - Monday June 08: WPC Days 3-7 U.S. Hazards
For Tuesday June 09 - Monday June 15: Today marks the first day of the Atlantic hurricane season and it appears likely to hit the ground running. Since late last week, model guidance has been consistent in the formation of a tropical low in the Gulf of Mexico associated with the remnants of tropical cyclone Amanda which originated in the East Pacific. The National Hurricane Center is currently monitoring an area of convection over the Yucatan region of southern Mexico that is expected to move northward in the Gulf later this week. Anomalously warm sea surface temperatures and low vertical wind shear predicted by the models remain conducive for the low to deepen into a new tropical depression throughout Week-1, with possible adverse impacts over the Gulf States heading into Week-2.
Despite the consistency in the models for development, there are some notable differences during the beginning of Week-2. Compared to this morning's GEFS guidance, the ECMWF favors a more westerly mean solution in bringing the closed low over parts of southeastern Texas prior to the start of Week-2. This is reflected in the 0z ECMWF deterministic solution which depicts a slower, and weaker northerly component to the track, as the low moves westward into southeastern Texas by Jun 9. Additionally, there are large differences in the 24-hour ensemble mean precipitation amounts ending on Jun 10. The GEFS places the bulk of the heavy rainfall east of the southern Plains, whereas the ECMWF is drier over the Southeast and depicts much higher amounts over eastern Texas and into Oklahoma as the low is expected to begin its extratropical transition. The GEFS reforecast tool indicates many coastal regions from the Lower Mississippi Valley and the Southeast at risk for heavy rainfall, whereas the ECMWF reforecast tool focuses this tropically related rainfall extending across the southern Plains and into the middle Mississippi Valley. As a result, a broad slight risk of heavy precipitation is posted to account for these differences, and a moderate risk is posted from eastern Texas along the coast to the Florida Panhandle for the early portion of Week-2. Additionally, a slight risk of high winds is issued mainly over the Lower Mississippi Valley. Regardless of the location of potential landfall, deep southerly flow and the advection of ample tropical moisture may lead to flooding across the Gulf coast and inland areas particularly if this system were to slow.
Across the higher latitudes, the 0z and 6z GEFS ensemble means feature anomalous troughing over the northwestern CONUS that is predicted to shift over the Great Plains, while anomalous ridging is expected to develop over the western and northeastern CONUS. Over the Central and Northern Plains, model surface analysis depicts periods of strong pressure gradients and there is agreement in reforecast tools highlighting a region with at least a 20% chance maximum sustained winds exceed the 85th percentile and 25mph. A slight risk for high winds is posted for Jun 9 to Jun 13. Relative to the predicted ridging aloft over the eastern CONUS, anomalously warm maximum temperatures are likely to persist from late in Week-1 into early Week-2, however, reforecast tools indicate the increase in temperatures are not likely to exceed hazards criteria. Although the ECMWF is more bullish with the prospect of daytime temperatures exceeding the 85th percentile, there is reduced likelihood that these temperatures will exceed 95 degrees F early in Week-1.
Over the southern CONUS, anomalously warm temperatures are also likely over parts of southern and western Texas early in Week-2. Reforecast tools highlight an area with at least a 20% chance maximum temperatures exceed 100 degrees F, and heat index tools also support elevated chances of values exceeding 105 degrees. However, given the uncertainty between the GEFS and ECMWF relative to the location of the predicted tropical system in the Gulf of Mexico to potentially impact the region, no temperature related hazards are included in the outlook. In the Southwest, ECMWF ensemble guidance favors the development of positive height departures over the southwestern CONUS to also increase the risk of excessive heat during late in Week-2. Reforecast tools reflect the increase in anomalous warmth, with at least a 20% chance daytime temperatures exceed the 85th percentile, however there is currently a low probability that these temperatures will exceed heat advisory thresholds for the region (110 degrees F). This area will continue to be monitored for excessive heat in the upcoming forecasts this week.
Forecaster: Nick Novella
$$ Please consult local NWS Forecast Offices for short range forecasts and region-specific information.
Resources
Week-2 Probabilistic Extremes Tool
GFS Ensemble Forecasts