Re: December 2018: Cold Dreary Weekend Ahead
Posted: Fri Dec 28, 2018 9:02 am
Friday morning weather briefing from Jeff:
2018 will end with wet and cold weather.
Surface cold front has pushed offshore overnight allowing a colder air mass to settle over the region with temperatures currently in the 40’s. The next upper level trough over the SW US will begin to move eastward allowing a costal trough and coastal low to develop along the TX coast over the weekend. Surface cold dome is fairly shallow and 850mb winds will turn S and SSW late today and tonight and “overrun” the low level cold air mass allowing moisture and lift to increase over the area. Lift is more general and sloping along isentropic surfaces instead of the more convective lift associated with the system Wednesday night. The result will be an increase in clouds from SW to NE this afternoon and then the formation of patchy light rain and drizzle tonight in early Saturday. Coastal trough will promote NE surface winds helping to lock in the cold air mass at the surface. Temperatures will remain in the 40’s for the entire weekend with cold air advection, clouds, and rain.
Mainly light rain, drizzle, and fog Saturday as lift is gentle over the area. Coastal low formation intensifies and moves up the TX coast Sunday night into Monday morning. Lift becomes increasingly stronger and moisture values peak Sunday night. Light rain will transition to more convective type showers and elevated instability may result in some thunderstorms…especially Sunday night. Think the warm sector air mass will remain offshore, but could get close to the coast Sunday night with some near surface based storms. Will need to keep an eye on the track of the coastal low for any potential inland movement of both heavier rainfall or any slight severe risks.
Storm system will move east of the area New Year’s Eve with a drier air mass working southward. A modified arctic air mass will push southward on New Year’s Day with much colder conditions overspreading the region. Yet another upper level system will approach TX around the 2/3 of Jan with some additional precipitation chances. A much colder air mass will be in place at that time especially by Wednesday morning. For now will keep everything liquid with additional light rainfall or drizzle around the 2/3, but will need to closely watch temperature profiles for the middle of next week especially over our N/NW counties.
Rainfall Amounts:
Widespread rainfall amounts of .50 to 1 inch appear likely Saturday-early Monday with some additional lighter total for the middle of next week. While these amounts of rainfall are not likely to cause any sort of significant flooding concerns, flood waves on area rivers are moving downstream from upstream locations and many watersheds are still in the response (rising) portion of the event from yesterday morning and will not crest until this weekend or early next week. Current thinking is that the weekend rainfall will maintain and extend the ongoing flood waves and recession times, but not likely to result in any new significant rises.
Hydro:
Watersheds continue to respond to the rainfall event from yesterday with several points now in flood or forecast to reach flood over the weekend.
Trinity River:
Moderate to major flooding is forecast at Liberty with minor flooding at Moss Bluff. River will remain above flood stage through all of next week.
East Fork of the San Jacinto River:
River is starting a secondary rise this morning at Plum Grove and New Caney as upstream flows from the Cleveland area move downstream. Minor flooding is expected at New Caney (FM 1485) this weekend. The river should fall below flood stage late Monday or early Tuesday.
West Fork of the San Jacinto River:
River has leveled off near flood stage overnight, but will begin a secondary rise today as upstream flows from Lake Creek progress downstream and reach US 59. Minor to moderate flooding is expected along the river downstream of US 59 with the main impacts being to low lying roads near the river and access to any elevated homes along the river.
Navasota River:
Moderate flooding is in progress and expected along the entire channel due to inflow run-off and reservoir releases from Lake Limestone.
Brazos River:
Significant inflows from the Navasota River will be moving downstream. At this time no flooding is expected at Hempstead or Richmond…although the river will be very high. Minor to moderate flooding is expected in Brazoria County at Rosharon through much of next week.
2018 will end with wet and cold weather.
Surface cold front has pushed offshore overnight allowing a colder air mass to settle over the region with temperatures currently in the 40’s. The next upper level trough over the SW US will begin to move eastward allowing a costal trough and coastal low to develop along the TX coast over the weekend. Surface cold dome is fairly shallow and 850mb winds will turn S and SSW late today and tonight and “overrun” the low level cold air mass allowing moisture and lift to increase over the area. Lift is more general and sloping along isentropic surfaces instead of the more convective lift associated with the system Wednesday night. The result will be an increase in clouds from SW to NE this afternoon and then the formation of patchy light rain and drizzle tonight in early Saturday. Coastal trough will promote NE surface winds helping to lock in the cold air mass at the surface. Temperatures will remain in the 40’s for the entire weekend with cold air advection, clouds, and rain.
Mainly light rain, drizzle, and fog Saturday as lift is gentle over the area. Coastal low formation intensifies and moves up the TX coast Sunday night into Monday morning. Lift becomes increasingly stronger and moisture values peak Sunday night. Light rain will transition to more convective type showers and elevated instability may result in some thunderstorms…especially Sunday night. Think the warm sector air mass will remain offshore, but could get close to the coast Sunday night with some near surface based storms. Will need to keep an eye on the track of the coastal low for any potential inland movement of both heavier rainfall or any slight severe risks.
Storm system will move east of the area New Year’s Eve with a drier air mass working southward. A modified arctic air mass will push southward on New Year’s Day with much colder conditions overspreading the region. Yet another upper level system will approach TX around the 2/3 of Jan with some additional precipitation chances. A much colder air mass will be in place at that time especially by Wednesday morning. For now will keep everything liquid with additional light rainfall or drizzle around the 2/3, but will need to closely watch temperature profiles for the middle of next week especially over our N/NW counties.
Rainfall Amounts:
Widespread rainfall amounts of .50 to 1 inch appear likely Saturday-early Monday with some additional lighter total for the middle of next week. While these amounts of rainfall are not likely to cause any sort of significant flooding concerns, flood waves on area rivers are moving downstream from upstream locations and many watersheds are still in the response (rising) portion of the event from yesterday morning and will not crest until this weekend or early next week. Current thinking is that the weekend rainfall will maintain and extend the ongoing flood waves and recession times, but not likely to result in any new significant rises.
Hydro:
Watersheds continue to respond to the rainfall event from yesterday with several points now in flood or forecast to reach flood over the weekend.
Trinity River:
Moderate to major flooding is forecast at Liberty with minor flooding at Moss Bluff. River will remain above flood stage through all of next week.
East Fork of the San Jacinto River:
River is starting a secondary rise this morning at Plum Grove and New Caney as upstream flows from the Cleveland area move downstream. Minor flooding is expected at New Caney (FM 1485) this weekend. The river should fall below flood stage late Monday or early Tuesday.
West Fork of the San Jacinto River:
River has leveled off near flood stage overnight, but will begin a secondary rise today as upstream flows from Lake Creek progress downstream and reach US 59. Minor to moderate flooding is expected along the river downstream of US 59 with the main impacts being to low lying roads near the river and access to any elevated homes along the river.
Navasota River:
Moderate flooding is in progress and expected along the entire channel due to inflow run-off and reservoir releases from Lake Limestone.
Brazos River:
Significant inflows from the Navasota River will be moving downstream. At this time no flooding is expected at Hempstead or Richmond…although the river will be very high. Minor to moderate flooding is expected in Brazoria County at Rosharon through much of next week.