textproduct: Columbia

SYNOPSIS

An extended period of dry weather is expected across the Midlands and CSRA with near to slightly below normal temperatures. The next chance of rain holds off until the weekend.

NEAR TERM /THROUGH TUESDAY/

Key message(s):

- Dry and cool conditions prevail.

Clear skies prevail across the region as high pressure continues to traverse the southeastern US. This surface high is gradually moving offshore, which will allow a bit of a pressure gradient to develop overnight. Event still, it looks like winds will be light enough and the airmass dry enough to yield good radiational cooling conditions tonight. Many areas recorded dewpoints in the low 30s this afternoon, and even without ideal radiational conditions, we should easily see temps fall into the low to mid 40s most places tonight. Bumped temps below the NBM because of this, as it usually does poorly with good radiational conditions.

SHORT TERM /TUESDAY NIGHT/

Key message(s):

- Warmer Tuesday, but dry weather likely continues ahead of a cold front.

- High pressure settles back in Wednesday with cooler conditions.

Tuesday and Tuesday Night: The forecast largely is on track for Tuesday where the upper trough will be moving through the Great Lakes through the day with a cold front off to our west. Low level flow should turn southwesterly through the day, leading to some warm advection and afternoon highs in the upper 70s to near 80. Moisture should also increasing slightly tomorrow in this regime, but an overall dry airmass should bring another afternoon with minimum RH values near 30%, possibly slightly lower. A couple isolated gusts to 20 mph will be possible as well during the afternoon. The only real change is recent CAM's and the mean HREF solution depict a bit better moisture convergence along the incoming front toward the evening with the HRRR being the most aggressive depicting a ribbon of PWAT's near 1.25". This has led to some CAMs forming a broken line of shower development along the front, but overall confidence in this is low with substantial dry air aloft and thus dry weather is expected to prevail at this time. The front then passes overnight, bringing another shot of cool/dry air.

Wednesday and Wednesday Night: Surface high pressure builds back in Wednesday behind the front as a very dry airmass moves in once again. Temperatures will be cooler behind the front, in the mid 70s, but the main story will be minimum RH values that fall to between 25-30% where it is not out of the realm of possibilities for a location to drop slightly below 25%. A couple more gusts just shy of 20mph could be possible into the early afternoon, but in general, gusts are expected to remain under this. Strong radiational cooling conditions are expected to set up overnight where chilly lows into the lower 40s are expected.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Key message(s):

- Dry weather persists through the late week and into start of the weekend.

- The next chance for rain arrives late this weekend.

Solid agreement remains in the evolution of a fairly progressive pattern through the extended. Thursday and Friday remain under the influence of surface high pressure with cooler temperatures and very dry air staying in place. Moisture starts to increase into Saturday as a compact shortwave moves into the southern Plains, turning flow out of the southwest with some shortwave ridging building into the FA. The GFS is the most progressive in the shortwaves progression, bringing it into the area by Sunday with associated rain chances while the ECMWF and Canadian are a bit slower and less amplified (ECMWF mainly). Thus some uncertainty exists to end the weekend and for the start of next week, but overall, rain chances increase during this time with continuing cool temperatures.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

VFR conditions expected through the forecast period.

High pressure continues to build into the region but winds have already gone calm at all terminals under clear skies. Expect near calm winds overnight then winds pick up from the southwest to around 10 knots after 15z through the afternoon, with some possible gusts up to 20 knots at times. Skies remain clear through much of the period although some higher clouds may arrive near the end of the 24 hr period.

Although widespread fog is not forecast, still can not rule out some fg/br at ags/ogb near the rivers where some steam fog formation could cause patchy ground fog late tonight.

EXTENDED AVIATION OUTLOOK...No significant aviation concerns through late week.

CAE WATCHES/WARNINGS/ADVISORIES

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