Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 114 PM EDT Sat Sep 06 2025 Valid 00Z Sun Sep 07 2025 - 00Z Tue Sep 09 2025 ...Stronger thunderstorms capable of severe and heavy rainfall over parts of the Northeast to Mid-Atlantic today... ...There are Air Quality Alerts over parts of the Northwest and Northern Rockies... An unseasonably strong large scale upper-level closed low dominates the Great Lakes again today, providing below average but very pleasant temperatures across the area. A few record low temperatures or low maximum temperatures dot the area today through early Monday, but departures from normal will moderate from 10 to 15 below average to 5 to 10 toward Monday. This broad closed low continues to press a cold front eastward through the Appalachian Mountains today, slightly faster northward into the Northeast. Ahead of the front, increased moisture and higher temperatures will result in unstable air and solid potential for showers and thunderstorms this afternoon; with stronger winds aloft further north, the potential for severe weather including a few tornadoes exists across New England with small hail and severe winds extending southward along the front into the Mid-Atlantic and eastern upslope portions of the Carolinas. The Storm Prediction Center (SPC) has a narrow Slight Risk (level 2 of 5) from SW Maine to Northeast Maryland, with a Marginal Risk (1 of 5) into northern Georgia. Coincidentally, enhanced moisture across the Mid-Atlantic will increase heavy rainfall potential for some of the thunderstorms as well. The Weather Prediction Center (WPC) has highlighted a similar area in a Marginal Risk of Excessive Rainfall (1 of 4); with an embedded Slight Risk (2 of 4) from Philadelphia across New York City into southwestern New England. This front will continue to sag southward across the Southeast tomorrow (Sunday) and intersect with a languishing area of enhanced deep layer moisture around a few weak surface lows and an old frontal boundary across the Florida Peninsula. The combination will maintain a risk of shower and scattered thunderstorm activity trough to early next week; the front will also stall across south central Texas. As such, WPC has maintained a Marginal Risk of Excessive Rainfall suggesting an isolated incident of flash flooding is possible across southern Texas and the Southern Florida Peninsula on Sunday with the risk continuing on Monday for Florida. Further west, lingering enhanced moisture under a slowly weakening upper-level ridge of high pressure will continue to suggest monsoon thunderstorms across portions of the Southwest. Some upslope flow from the southern Plains will help to further concentrate moisture and therefore, thunderstorm activity within the larger Marginal Risk of Excessive Rainfall (across the Four Corners to the adjacent terrain to the Snake River Valley into the Blue Mountains of Oregon), a small Slight Risk of Excessive Rainfall has been placed along the Sacramento and southern Sangre de Cristo Ranges in New Mexico. Local forecast offices have placed flood watch across similar areas, particularly the burn scars of those areas. By Sunday, the ridge will continue to be suppressed by a subtle shortwave trough out of the northern stream dropping through southwest Canada. This will help to press out a weak frontal zone or support some weak Chinook downslope flow to bring warmer temperatures through the American Rockies into the High Plains and eventually Northern Plains by Monday. Temperatures into the 80s will near 90 which is about 5 to 10 degrees above normal. Some widely scattered showers may come with the weak front but should light. West of the frontal zone in the far western part of the upper-level ridge, weaker winds, lower moisture will maintain the potential for fire weather conditions and low air quality due to smoke from ongoing fires. Red Flag Warnings are up for portions of Oregon and Washington and SPC has delineated areas of Dry Thunderstorm potential today into tomorrow for OR, WA and ID. The Air Quality Alerts are in affect for Eastern Washington, Northern Idaho, Western Montana, Western Wyoming and northwest Colorado. Gallina Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php