textproduct: Columbia

WHAT HAS CHANGED

Added the possibility for elevated fire weather concerns to remain this week. Separated the last key message into two sections discussing the midweek frontal passage and warming trend this weekend. Aviation discussion updated for 18z forecast.

KEY MESSAGES

- 1. Elevated fire weather conditions are expected this afternoon.

- 2. A weak cold front moves through mid week with rain chances.

- 3. Dry conditions are expected with temperatures warming above normal this weekend and early next week.

DISCUSSION

Key Message 1: Elevated fire weather conditions are expected this afternoon.

The southeast will remain within a cool and dry pattern following yesterdays cold front. Northeasterly flow has continued to advect drier air into the region today with dew points steadily falling. RH values this afternoon should near critical values between 30-35%. A couple spots falling below 30% will be possible. Winds are gusting close to 15-20 knots in some places as mixing has occurred, but winds should start decaying through the remainder of the evening. Additionally, several days this week are expected to have RH values nearing critical levels, however, winds remain below thresholds for any fire weather products.

Key Message 2: A weak cold front moves through mid week with rain chances.

A fairly weak but dry cold front is expected to drop out of the Midwest/Great Lakes and across the Ohio Valley into the Appalachians late Wednesday into Thursday. Guidance continues to trend toward drier solutions across ensemble and global models, favoring a weaker and somewhat moisture-starved frontal passage. Poor trough orientation will not be as conducive for moisture return ahead of the boundary. As some high-res guidance reaches toward this period, there continues to be an indication of isolated to perhaps scattered showers developing Wednesday evening mainly toward the Pee Dee. A look at the recent REFS solution does indicate this potential as well where limited elevated instability could allow for a couple thunderstorms. The 12z MPAS-RRFS also a broken line of showers/storms moving through, so despite the trend toward a drier solution, at least slight chance PoP's seem reasonable mainly over the northern and eastern Midlands.

Key Message 3: Dry conditions are expected with temperatures warming above normal this weekend and early next week.

Drier conditions are expected to return, although a lingering upper trough should keep temperatures near to slightly below normal to end this week. After this, a rebuilding and influence from the Bermuda High is expected to expand westward over the southeast. The sharp ridge will bring back a blocking pattern over the Carolina's with broad and moist southwesterly flow draped over much of the area. Above average temperatures are expected Saturday through Tuesday next week with high temperatures each day reaching into the 90s. This period of above normal temperatures is highlighted well in the EC EFI as values reach between 0.8-0.9 starting Sunday. Dew points are generally expected to remain in the upper 50s to lower 60s, however, a relatively weakly unstable and capped environment supports for limited to isolated convection.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

VFR conditions remain likely through the period.

A quiet period of aviation weather is expected through 18z Wednesday. A low pressure system is currently working its way through the Gulf of Mexico, sending widespread mid and high level clouds atop the area. Meanwhile, a surface high pressure system is anchored off the coast of the Mid-Atlantic, ushering in dry surface air and breezy northeasterly or easterly winds to the TAF sites. As we get into tonight, the clouds are gradually expected to lift higher in the atmosphere until they really aren't around anymore as the low pressure system shifts off shore and to the east. We'll still be under the influence of this, but by midday Wednesday our winds are expected to rapidly shift out of the west or southwest as another cold front approaches. This generally looks to occur after the end of this TAF period. VFR conditions expected throughout as a result of all of this.

EXTENDED AVIATION OUTLOOK...Scattered showers and thunderstorms possible Wednesday over the northern and eastern Midland. Otherwise no rainfall with mainly vfr conditions expected.

CAE WATCHES/WARNINGS/ADVISORIES

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