From Jeff
Major Winter Storm to impact SE TX starting Monday evening.
Widespread significant disruption to nearly impossible travel late Monday evening into Wednesday
Dangerously cold conditions Monday-Wednesday
Discussion:
Initial cold front has cleared the area with cold conditions in place this morning. Freeze line is generally along and north of I-10 and under clear skies today temperatures will warm into the lower to mid 40's. Push of arctic air arrives into the region tonight with temperatures falling below freezing at many locations. There has not been any adjustments to the temperatures for Monday and Tuesday mornings with mostly mid to upper 20's over most of the region and low 20's north of HWY 105. Still watching Wed AM closely for "really" cold with expected snow on the ground and clearing skies…lows well into the 10's for a good part of the area and low to mid 20's toward the coast is in the cards.
Gusty northerly winds today through Tuesday will result in wind chills in the 10's and 20's…so you'll need layers if going outside.
Many areas will fall below freezing on Monday evening and potentially remain below freezing into Wednesday afternoon and even then only may warm a few degrees above freezing so sub-freezing duration of 36-45 hours is possible over the area.
Monday AM Forecasted Low Temperatures:
North of HWY 105: 22-26
North of I-10: 25-29
Houston metro (inside Beltway): 27-29
Coastal Counties: 28-31
Beaches/Galveston: 31-34
Tuesday AM Forecasted Low Temperatures:
North of HWY 105: 24-26
North of I-10: 25-28
Houston metro (inside Beltway): 27-29
Coastal Counties: 27-30
Beaches/Galveston: 30-32
Wednesday AM Forecasted Low Temperatures:
North of HWY 105: 14-17
North of I-10: 15-18
Houston metro (inside Beltway): 17-19
Coastal Counties: 19-22
Beaches/Galveston: 28-30
Maximum preparations and precautions for sub-freezing conditions for many hours should be completed today. Failure to complete proper precautions may result in significant damage to vegetation and infrastructure.
Protect sensitive vegetation.
Protect any exposed outdoor pipes (sprinkler systems should be shut off and properly drained). Pipes in attics and along exterior walls of structures could freeze at these levels.
Prepare proper shelter and warmth for animals and livestock and make sure water sources are not frozen.
Persons should limit outside exposure to a minimum.
Winter Storm:
Significant winter storm will impact the area late Monday into Tuesday with widespread travel impacts that will linger well into Wednesday and possibly Thursday.
Upper level trough will move into Texas late Monday with surface low pressure being forced along the lower TX coast which will start to bring moisture northward into the cold air late Monday. Clouds will increase Monday afternoon and expect to see precipitation develop by mid to late Monday evening and expand across the region from the southwest. We are now within the range of some of the more reliable high resolution models that are just slightly warmer aloft than the global guidance has been suggesting which suggest more of a freezing rain and sleet profile, but the temperature profiles are not all that different and the air column cools with time toward an all snow event into the day on Tuesday. However, will need to keep an eye on the profiles over the next 24 hours as a pesky warm layer aloft could change the precipitation type and accumulation amounts. Will still favor mostly all snow north of I-10 and a mixture of precipitation south of I-10 (looking more sleet than freezing rain).
Guidance continues to exhibit numerous banding features with this event which suggest a small amount of instability and strong lift within the near saturated sub-freezing air column. This can bee seen in the guidance precipitation fields showing banding structures and also in the SREF plumes with significantly varying storm totals with individual memebrs. It appears there will be a period of potentially heavy sleet and snow bands over the area that will result in rapid accumulation. Visibility in the heavier snow bands may fall to less than .25 of a mile at times. As with a heavy rainfall event…where any of these heavier bands establish is unknown but will result in higher totals than nearby areas. Guidance has been generally favoring an area along and just north of the I-10 corridor from west of Houston to Liberty County for some of the higher totals and areas northeast of the metro area.
Accumulations:
Widespread snow/sleet amounts of 1-3 inches can be expected over much of the region with isolated banding totals of 4-6 inches and possibly higher. Any accumulations of freezing rain look to be toward the coast and southwest of the metro area and average less than .10 of an inch. Should there be more sleet than snow…these accumulation amounts would lower some.
Impacts:
Widespread significant impacts to travel is likely with near impossible travel expected on Tuesday into early Wednesday with potentially several inches of snow and ice on all roadway surfaces. Prolonged cold temperatures will result in slow recovery and melting post event with snow likely lingering into Thursday and possibly longer depending on depths.
Be at a safe location by 600pm Monday evening for the duration of this event.