Scientific Forecaster Discussion
fxus62 kcae 121121
Area forecast discussion
National Weather Service Columbia SC
621 am EST Thu Dec 12 2019
dry high pressure will build into the area from the north
today. Moisture will return tonight into Saturday as low
pressure moving northeast from the Gulf of Mexico crosses the
southeastern states. High pressure will bring dry weather and
moderating temperatures Sunday into Monday. Another cold front
will cross the area Tuesday, bringing more rain showers.
Near term /through tonight/...
surface high pressure over the mid Atlantic region will move off
the coast this afternoon. Cold air will continue advect into
the region as high pressure ridges in from the north. Clear
skies are expected through the morning given our dry airmass
with precipitable water values generally one quarter inch or less. High
temperatures will remain below normal...in the upper 40s to
Clouds will increase from south to north through the afternoon
with wedge conditions setting up. Expect most areas to remain
dry through the daylight hours. Rain chances will increase from
the south this evening as isentropic lift increases. Shortwave
energy will be moving through the region late tonight while an
area of low pressure develops over the Gulf of Mexico. Moisture
will deepen across the area from south to north with
precipitable water values reaching an inch or more overnight.
Widespread rain will develop overnight with the greatest amounts
across the west. Could get a rumble or two of thunder late
tonight as moisture is transported above a cool surface layer
resulting in destabilization across the csra and western
midlands with MUCAPE from 200-400 j/kg and showalter index of
minus 2. Overnight lows will be in the mid 30s to lower 40s.
Temperatures should remain too warm for any frozen
Short term /Friday through Saturday night/...
rain will continue on Friday due to isentropic lift combined
with abundant moisture ahead of a low pressure system and warm
front over the northern Gulf of Mexico. This system will deepen
and lift northeastward across Georgia and South Carolina
through Friday night. Abundant moisture will be in place with
precipitable water values around 1.3 inches which is around 225
percent of normal for this time of year. By Saturday morning,
expect the low to be centered well northeast of the area over
the mid-Atlantic coast. Therefore, most of the rain should
occur Friday and Friday night, with amounts between one and two
inches expected, which may be moderate to heavy at times. Most
of the rainfall should be gone from the area by Saturday
afternoon. Dry conditions with clearing skies will follow for
Wedge-like conditions will be in place on Friday, with below
normal temperatures and highs only in the mid 40s north to low
50s south. Temperatures will then remain fairly steady through
Friday night, and are then expected to warm into the mid 50s to
mid 60s on Saturday with low-level flow increasing and becoming
west-southwest. Despite the clearing on Saturday night, winds
will stay up and mixing will keep temperatures above freezing,
with lows in the upper 30s to low 40s.
Long term /Sunday through Wednesday/...
surface high pressure will be over the region on Sunday with a
dry air mass. Another cold front will cross the area Monday
night into Tuesday bringing the next chance of rain to the area.
Good southwest flow associated with this system will keep
temperatures mild during this period with highs in the 60s. Expect
the front to shift east by Tuesday night with rain chances
diminishing, skies clearing, and temperatures falling into the
30s. Dry high pressure will build back into the region for
Wednesday, but temperatures will remain cool behind the front.
Aviation /12z Thursday through Monday/...
VFR conditions through 00z Friday. Cig/vsby restrictions
developing after 13/00z.
High pressure over the mid Atlantic states will ridge into the
Carolinas and Georgia from the north. This will allow cool, dry
air to push into the taf sites today through NE winds. Surface
winds will remain light during the early morning hours with
winds at 2000 ft agl 30 to 35 knots as indicated by BUFKIT and
VAD wind profile. Have indicated low level wind shear through 14z for
Northeast winds will increase after 14z as the nocturnal
inversion breaks with speeds around 10 kts. May see gusts to 20
kts. Clouds will increase/lower from the south during the
afternoon as wedge conditions develop. Rain will move in from
the south after dark. Should see MVFR/IFR cig/vsby restrictions
develop after 13/00z as wedge conditions strengthen and
widespread rain overspreads the taf sites.
Extended aviation outlook...a low pressure system will bring
rain and IFR/MVFR restrictions Friday into Saturday morning.