As of 10 AM Monday, the central U.S. storm system was beginning to become better organized. A surface low was located over SW KS. A warm front was stretching from the low to the NE into southeastern NE and eastward across central IL/central IN/central OH. South of the warm front, temperatures are already warming nicely into the 40s/50s. North of the front remains chilly with temperatures into the 20s. A secondary surface low was located across north-central SD. A cold front stretched southward from this secondary low connecting to the surface low in SE KS and continued southwest from the low in KS through northern NM. A broad area of snow was occurring from NE MT eastward into NW WI and southward into NE WY and western SD.
By this evening, the low in SE KS will have remained mainly stationary; however, the cold front across the Dakotas will have moved eastward into western MN. The warm front will stretch from northern OH into northern IL across southern IA into southeastern NE and southwestward into KS to the surface low. A band of wintery mix will stretch along the northern edge of the warm front from NW PA into SE MI with snow stretching from MI across much of WI, MN, SD, southern ND, WY, and northern CO. Heavy snow is possible from Rapid City, SD-Aberdeen, SD-central MN. Up to 6” is possible in this band through midnight, tonight. Rain showers will also begin to develop in advance of the surface low across eastern KS into eastern TX.
Overnight, accumulating snow will stretch from western NY into central MI-central WI-central MN-SD-NE-northeast IA-southwest KS-northern NM-eastern CO-WY. Heavy snow will be likely across much of southeastern MN, across central WI and into northern lower. MI. Snowfall in this band between midnight tonight and 6 AM CT, Tuesday, will range between 2”-5”. In addition, a band of heavier snow will be likely across SE CO/north-central NM where 2”-5” is likely tonight. In advance of the surface low, from IN-western MO and southward into eastern TX, moderate to heavy rain is likely. Thunderstorms will also be possible, mainly from SE MO, across AR and into eastern TX. Rainfall of 1”-2” will be possible across SE KS, southern MO, eastern OK and AR.
During the day Tuesday, the heaviest rains will shift eastward from western OH to eastern LA. Snow will be likely from the Panhandles of TX/OK, northeastward to northern IL and northern MI. The heaviest snow will fall from eastern IA across southern WI/northern IL and upper Lower MI. Snowfall in this band will range between 4” and 8”.
Tuesday night, moderate to heavy rain will stretch from New England into PA and along the spine of the Appalachians into northern AL and southwestward into eastern LA. The heaviest rain will be associated with thunderstorms from southern TN into eastern LA. Some thunderstorms in this band may become severe and rainfall amounts of up to 3” will be possible. Cold air will continue to sink southward and make its way into northern TX and northeastward into the Mid-MS Valley, and eastern Great Lakes. Any lingering precipitation in these regions will change over to a period of snow. I anticipate that snow will likely occur for a period of time from north-central TX through OK into the Ozarks and northeastward into MI. Up to a 1” of accumulation will be possible across NE OK/NW AR/SW MO in the Ozarks.
On Wednesday, heavy rains will remain likely from the central Gulf coast into southern New England. Attention then turns to the potential for development of a Gulf of Mexico Low. Models are beginning to be in better agreement with this potential but exact track and amount of cold air that pushes southward remains major differences. This system will be monitored closely for the second half of the week.
As of now, I forecast a low to develop in the north-central Gulf of Mexico south of New Orleans by Wednesday evening. The low will track to the east and be south of Mobile Bay by Thursday morning. It will then begin to turn more northeasterly and move into southwestern GA by Thursday evening. It will then rocket northward along the eastern coast on Friday. This track will bring more significant rainfall to the Gulf Coast and SE and along and east of the Appalachian chain. It appears most of the precipitation will be in the form of rain. The BIG question is how much cold air sinks into the SE and Mid-Atlantic and how fast. My concern currently from those of you from northeastern AL northeastward along the spine of the Appalachians is the potential for enough low level cold air to be in place that freezing rain/sleet may be a potential, mainly Thursday night into Friday morning. Since this is still several days out, much can change regarding the specifics of this event. More confidence will occur as we draw closer to the event itself. This system will also be a watcher from the Mid-Atlantic to New England, especially along the I-95 corridor for a potential Nor’easter, too. Significant snow would be possible from northern VA, across eastern PA and into eastern NY, Friday into Saturday.