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Jeff says continued wet and cold:
Woke up to 36f and light rain/drizzle/mist this morning. We're now in a heat wave with the temp soaring to 40f. I just heard a local OCM mention the possibility of "wintry precipitation" the next 2 mornings. Guess I'll have to do some checking of models, etc.Cold and Wet
Cold air mass is firmly entrenched over the area this morning with light rain and drizzle being reported along with some sleet mixing with the rainfall NW of a College Station to Giddings line.
Cold front that moved across the area early yesterday is now out over the NW Gulf of Mexico with warm moist SSW flow riding up and over the surface cold dome. Morning soundings from Lake Charles and Corpus show the surface cold dome is only about 2000-3000 feet deep above the surface with warm air (above freezing) extending up to near 13,000 ft. Fort Worth sounding is all below freezing so the front slope is shallow near the coast and then deepens inland falling below freezing just north of our northern row of counties…likely near the 850mb front. Fairly strong shortwave in the SW flow aloft has brought the formation of drizzle and light rainfall to the northern ½ of SE TX this morning. College Station has been reporting a light rain mixed with sleet this morning, but surface temperatures are in the mid 30’s and there will be no accumulation. This short wave will move east of the area by early afternoon ending the rainfall. Clouds may decrease late this afternoon with mostly cloudy to partly cloudy skies tonight.
Tuesday-Wednesday:
Models have trended toward the ECMWF solution over the past 24 hours or a stronger and more cut-off upper level storm system for the mid week period. This keeps the cold air locked into place and supports more widespread precipitation Tuesday night-Wednesday. Expect clouds to increase from southwest to northeast on Tuesday as strong lift begins to spread eastward out of MX into TX. Isentropic lifting of a moist Gulf air mass over the surface cold dome will support to develop of drizzle and light rainfall by Tuesday night. NAM model is much more aggressive in developing rainfall across the region while the GFS keeps most of the rainfall near the coast and very light. Other item of interest is the surface temperatures during the overnight and morning hours on Wednesday. Both the NAM and GFS show surface temperatures falling to near freezing (especially north of HWY 105) Wednesday morning, but this is a very shallow layer of potential sub freezing air only about 1000 to 2000 ft thick. Other questions surround the amount of dry air at the surface and the ability of precipitation to reach the ground if the near surface layer is fairly dry. All of this is further complicated by the fact that the dry surface layer can be cooled a few degrees by precipitation falling into this layer. To even further complicate the issue, with the large area of warm air aloft, rain drops falling through this warm layer could offset any near surface evaporative cooling. Would like to see additional model runs help fine tune the freezing line and come into better agreement with both the precipitation placement and amounts before thinking about any freezing rain across the area for Wednesday morning.
Extended:
Main upper level system should progress east of the area on Thursday with decreasing clouds and slowly warming temperatures. Cloudy and cold conditions will be replaced with partly cloudy and warmer conditions. Highs will warm from the 40’s today-Wednesday into the 50’s Thursday-Sunday. Long range forecast models have been suggesting a surge of very cold arctic air deep into the US for the week of the 21st. While the pattern seems to support a cold air outbreak into the US, the trajectory of the incoming cold air is aimed more toward the MS valley and eastern US with a glancing blow expected for the southern plains. Will follow this line of thinking and support a strong cold frontal passage early next week, but keep the brunt of the arctic air NE of TX.
