#173 Postby jeff » Tue Jan 16, 2007 3:35 pm
Ice Storm Warning remains in effect.
Updating to include snow and 1-2 inch accumulations NW ½ of SE TX tonight.
Discussion:
Radar really starting to fill in out west with moderate snow falling and accumulating along the I-35 corridor. Strong forcing associated with next upper impulse resulting in rapid precip. development this afternoon. METAR obs. and public is reporting widespread snow and sleet mix as precip. is cooling the air column and extrapolation of radar snow bands bring that across our NW half of SE TX. Also getting reports of ice pellets in Conroe within the last hour. Accumulations of ice, snow, and sleet are nearing 1-2 inches along the I-35 corridor and spreading ENE toward our area.
Will draw a line from Columbus to Conroe to Livingston and show this as the change over line between freezing rain and snow. Will go with ¼ to ½ of ice accumulation north of this line and include changing to snow after midnight with 1-2 inches of accumulation.
South of this line including Harris, Fort Bend, Waller, and Montgomery counties expect freezing rain to onset this evening and continue through early Wednesday morning. Ice accumulations of ¼ of an inch is expected. Freezing rain may become mixed or change to sleet after midnight. I am not convinced the surface temp. will reach freezing across Harris County…however wet bulb temps. suggest otherwise with dewpoints well into the mid 20’s there is plenty of room for air column cooling.
Mainly exposed surfaces will accumulate ice, however if sleet develops surface roads may accumulate crusted icing while bridges and overpasses will glaze from freezing rain.
Travel N and W of Harris County looks to become hazardous this evening and remain that way through midday Wednesday. Several roads are already icing and glazed and this will worsen as the evening progresses and precip. overspreads the region. Freezing rain is already in progress N and W of Waller and Montgomery counties and should onset across Harris County by mid to late evening may be sooner if the surface temps can fall to freezing.
We shall see what transpires…radar looks quite nasty as of now…however a similar picture was noted last night and the event stayed to our N.
Looking Ahead: May begin to entertain problems for this weekend as saturated grounds and already flooding rivers may be impacted by significant rainfall. Moderate to major flooding is ongoing along the W folk of the San Jacinto River and minor flooding along the Trinity River. Rises to bankfull are expected along the lower Brazos River and San Bernard River. Hopefully by this time any threat of freezing/frozen precip. will return to its home further north and stop causing me headaches.
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