Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 356 PM EDT Mon Sep 27 2021 Valid 00Z Tue Sep 28 2021 - 00Z Thu Sep 30 2021 ...There is a Marginal Risk of excessive rainfall over parts of the Southwest through Wednesday morning... ...Temperatures will be 10 to 25 degrees above average over parts of the Northern/Central Plains into the Upper/Middle Mississippi Valley... ...There is a Critical Risk of fire weather over parts of the Great Basin... Upper-level low and moisture over the Southwest will aid in producing widely scattered showers and thunderstorms over the area through Wednesday. Some of the thunderstorms will have heavy rain, but this will be isolated. Therefore, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Southwest through Tuesday morning. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. The upper-level low over the Southwest will slowly move northeastward to the Central Rockies, becoming absorbed by a deep upper-level trough over the Rockies by Wednesday. The circulation around the upper-level low will pull moisture will flow northward over the Southern/Central Plains, setting the stage for showers and thunderstorms to develop over parts of the Central and Western Gulf Coast on Tuesday, expanding into the Central/Southern Plains by Tuesday evening. Meanwhile, a front extending across the Northeast to the Great Lakes will settle southward to the Mid-Atlantic by Tuesday evening and over the Carolinas by Wednesday evening. The front will aid in producing showers and thunderstorms along and ahead of the front starting on Monday afternoon over parts of the Lower Great Lakes into the Northeast that will move into parts of the Mid-Atlantic to Southern New England by Tuesday afternoon then dissipate by Wednesday morning. Furthermore, the rain will continue over parts of the Northern Intermountain Region to late Wednesday morning. In the meantime, a front extending from the Northern Rockies into Northern/Central California will move slowly eastward to the Northern Plains to the Southern Rockies by Wednesday. The system will start producing rain over parts of the Northwest/Northern California that will expand into parts of the Northern Intermountain Region by Tuesday morning. The rain will continue over the Pacific Northwest due to onshore flow through Wednesday morning, then weakening as the onshore flow ends. However, moisture from the Gulf of Mexico will stream northward over the Plains as the front moves onto the Northern/Central Plains, producing showers and thunderstorms along and ahead of the boundary through Wednesday. Additionally, upper-level ridging ahead of the boundary will allow temperatures to become 10 to 25 degrees above average over parts of the Northern/Central Plains into the Upper/Middle Mississippi Valley. Moreover, gusty wind ahead of the front over the Great Basin led to conditions favorable for a Critical Risk of fire weather over parts of the Great Basin. Therefore, Red Flag Warnings are up over portions of California, Nevada, and the Northern Intermountain Region. Ziegenfelder Graphics are available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php