Low pressure over the northern Texas panhandle, part of a large storm system with primary low pressure in Wisconsin, will move eastward tonight, with secondary development occuring in southern Texas tomorrow morning. The secondary low will tap into Gulf moisture spreading a large precipitation shield across the plains states. This will produce widespread heavy snowfall, flooding, and severe thunderstorms. The low will move NE to a position over Tennessee Tuesday morning. Model consensus has it located in western Tennessee, however there is still a slight eastward trend to consider.
Precipitation will spread into the region by early Tuesday morning. Due to the timing around the usual time of minimum temperature, we could see precipitation fall briefly as freezing rain, but likely without any noticable accretion.
Showers, mainly light will continue through Tuesday. Frontal boundary will cross to our south, allowing surface temperatures to remain near 40 or below, while south of the mass pike, high temperatures could exceed 50.
Low pressure approaches from the southeast Tuesday Night. Warm front nudges north, bringing with it better dynamics, with max omega near -15, as well as PWATs near 1.0". Precipitation will increase in intensity at that time and could fall heavy at times between midnight and 9am Wednesday. Some spread in the models accumulation forecast. Still, high confidence in at least 1.0" before precipitation ends abruptly by noon.
Very interesting situation for Wednesday morning. Low pressure will move into NY Tuesday night and then be swept east across the region Wednesday morning. Heavy precipitation will be likely at that time. Frontal boundary will be located to our north, but the models have been trending stronger with high pressure in SE Canada, suggesting cold air may not be scoured out as quickly. Cold air damming could allow rain to change to freezing rain after midnight Wednesday, and continue through Wednesday morning during the period of heaviest rates. A couple things to consider. Precipitation will be occuring at the normal time of minimum temperature. Anomalously high snow pack could work toward increasing the resistence of surface cold. However, there is also the time of year to consider, when now solar heating is becoming stronger. Climatologically speaking, ice storm potential ends by March.
There is considerable uncertainty for Tuesday Night and Wednesday morning. Slight shifts in surface temperature will have a large impact. At this time, the possibility exists for yet another signficant ice storm to tack onto a winter that has been notorious for precipitation type issues. I am becoming more confident in >.25" of ice accretion Wednesday morning.
--- Snowday Outlook ---
As said, considerable uncertaintly with regards to precipitation type. If the ice storm pans out, a delay will be likely, and even a cancellation will be possible.
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