Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
1055 am EDT Thursday Jul 24 2014
an upper trough crossing the eastern Continental U.S. Will push a cold front
into the area late today. Scattered thunderstorms are expected
ahead of the front this afternoon and evening. The front will
become stationary across the region Friday and weaken.
Thunderstorms will be isolated into the weekend and temperatures
will be above normal.
Near term /until 8 PM this evening/...
no significant changes required to the forecast for this afternoon.
Current radar checking clear across our forecast area (fa)...with
some shower/thunderstorm activity moving east across NC. Expecting
better convective development for our forecast area late this afternoon and
evening. Short wave energy moving southeast from the middle west to the middle
Atlantic will slightly deepen the upper trough over the east Continental U.S. And
drive a weakening cold front into the region late today. Best
moisture just to our north across central and east NC/VA...with
precipitable water (pw) around 2 inches...with slightly lower precipitable water
values across most of our forecast area. Moderate instability projected for our
forecast area this afternoon and evening...with best 0 to 6 km shear/brn
values near and to the NE of our NE forecast area. NE forecast area in favorable
entrance region of upper level jet. Combination of slightly better
moisture...instability...and deep layer shear to our NE will favor
severe risk across our NE forecast area. Storm Prediction Center upgraded day one outlook to
slight risk severe clipping our NE forecast area.
Short term /8 PM this evening through Saturday/...
front will move slowly through the area during the evening with
scattered to numerous showers and thunderstorms. Deeper moisture
shifts to the coast after midnight and expect decreasing probability of precipitation
through the overnight. MOS temperatures look OK.
Front appears to become stationary/diffuse across the southern
South Carolina Friday/Saturday. Weak middle level short waves
possibly moving through the area but weak upper level Flat Ridge
building later on Saturday. Deeper moisture to the east. Air mass
weakly to moderately unstable. Focus for scattered thunderstorms
Friday afternoon in the east midlands near frontal
boundary/convergence area. Convection expected to be more isolated
on Saturday with weaker forcing. Temperatures above normal on
Saturday. Prefer warmer mav guidance through the period with
recent cool bias of the met.
Long term /Saturday night through Wednesday/...
models continue to trend toward an amplification of the long wave
pattern with a ridge in the west and a trough in the east.
The upper pattern once again amplifies early next week with a
ridge in the west and a deep trough. This should push another cold
front toward the region on Tuesday. We kept a chance of
showers/thunderstorms Friday diminishing to isolated for Saturday. Chance
probability of precipitation were retained for Sunday and Monday. Mainly dry for Tuesday
and Wednesday as high pressure builds in from the northwest.
Temperatures should be near normal Saturday through Monday...then
slightly below normal Tuesday and Wednesday.
Aviation /15z Thursday through Monday/...
VFR conditions expected outside any late afternoon/evening
Frontal boundary to move through the region late today and tonight.
The front and diurnal heating expected to promote scattered
thunderstorms late this afternoon and evening. At this time...since
confidence of thunderstorms and rain specifically affecting the terminals
limited...will handle in the tafs with vcsh and upgrade later
if/when confidence warrants. Fog threat late tonight/early Friday
monring will depend on extent of rain that may occur at the
terminals and extent of any lingering cloud cover. Limited
confidence at this time...so will not include mention in the tafs.
Extended aviation outlook...slight thunderstorms and rain chance Friday near the
southern terminals...ags/ogb. Minimal convection expected Sat/sun.
Better thunderstorm chances Monday.