textproduct: Columbia

SYNOPSIS

Today should be mostly dry but cool. Monday night will see an increase in rainfall coverage ahead of an area of low pressure. A period of moderate to heavy rainfall is expected as this low moves through into Tuesday. High pressure then builds back in for Wednesday and Thursday before another system may take aim at the region to end the week.

NEAR TERM /THROUGH TONIGHT/

Key message(s):

- Cool and drier through the daytime hours, then increase in rain potential after sunset tonight. - Widespread moderate to heavy rainfall possible tonight.

A cold front is off to the south of the area this morning, with north to northeasterly winds beginning to set up a wedge type flow east of the Appalachians. Although it should be dry throughout the daytime hours, there will still be some cloud cover across the area. With weak cold advection and the expected clouds, temperatures will remain on the cooler side with highs ranging from the upper 40s north to the middle 50s across the far south.

After sunset tonight, expect a rather rapid increase in rainfall potential will occur to by midnight as an area of low pressure in the Gulf begins to strengthen and rapidly move northeast into the area, ending up near or off the South Carolina coast overnight. Will be a good amount of isentropic lift and moisture advection over top of the surface wedge, and due to this, rainfall cloud become moderate to heavy at times during the night. Rainfall amounts overnight expected to range between 0.50 to 1.00 inch. With the clouds and rain, another cool night will be on tap, with lows ranging from the mid-30s north to the mid-40s south.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/

Key message(s):

- Rain exits from southwest to northeast on Tuesday, with dry weather expected Wednesday. - Cooler than average temperatures continue.

Tuesday and Tuesday night: Rain is very likely (>90%) to be ongoing Tuesday morning as an upper trough and surface low continue moving across the region. Some of the rain could be moderate to heavy at times at the start of the period, but the intensity is forecast to decrease through the morning as the trough and surface low move to the northeast. As these features move away from the forecast area, expect the rain to end from the southwest to northeast. Ensembles are indicating a moderately high chance (60-70%) of seeing more than 1" of total rainfall with this system by the time all it's all said and done. However, there remains some disagreement between the models of where the heaviest amounts will fall. Regardless, the entire area is likely to see some beneficial rainfall. Temperatures are forecast to be slightly warmer than Monday, but still below average for this time of year. High pressure begins moving into the region behind the exiting system, allowing for clearing skies and chilly temps. The northwestern portions of the forecast area has a good chance (>70%) of dropping to, or below, the freezing mark.

Wednesday and Wednesday night: High pressure continues to build over the region, leading to a dry and cool day across the forecast area. Temperatures are forecast to be several degrees below average under mostly sunny skies.

LONG TERM /THURSDAY THROUGH SUNDAY/

Key message(s):

- Active pattern continues as high temps fluctuate through the period. - Another round of showers possible to end the work week.

The overall progressive pattern is anticipated to keep the weather active through the long term period. The next system is forecast to take shape over the western Gulf and mover toward the area toward the end of the week. This should allow for a brief warm up for Thursday, with the next chances for precipitation arriving Thursday night/Friday morning. Details on timing still need to be worked out as we get closer. At this time, temperatures at the onset of precipitation still appear to be too warm for any snowflakes, but will continue to monitor. If there were any snowflakes mixed in, it would most likely be confined to the very northern Midlands. After this system moves through, the temperature fluctuations continue.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Mainly vfr at terminals through the day, then deteriorating conditions after sunset and by midnight as low moves into the region.

Cold front is off to the south of all terminals. North to northeasterly winds will begin to help set up surface wedge conditions through the day. VFR conditions should occur through the daytime hours though, with mainly some mid and upper level cloud cover and dry forecast. Changes expected though tonight after sunset and by midnight as an area of low pressure tracks towards the region. Deteriorating conditions should occur rapidly once they start at each taf site, with ceilings and visibilities both dropping into mvfr, then into ifr-lifr as rainfall moves into the forecast area. Those conditions will then persist through 12z Tuesday morning. Winds today will be north to northeasterly with speeds between 5-10 and a few higher gusts possible through the day and into tonight.

EXTENDED AVIATION OUTLOOK...The next weather system will keep the potential for restrictions in rain into Tuesday morning. Additional restrictions possible late in the week.

CAE WATCHES/WARNINGS/ADVISORIES

SC...None. GA...None.