Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Raleigh NC
1005 am EDT Tuesday Oct 13 2015
Synopsis...a mostly dry cold front will cross the area late this
afternoon/evening. High pressure will build into the area on
.Near term /through tonight/...
As of 1005 am Tuesday...
The prefrontal band of showers that moved through the mountains
early this morning has dissipated and we are just left with a narrow
band middle clouds crossing the Piedmont. Strong height falls...60-
120m...give just a glancing blow today as the main northern stream
trough and primary cold front...which stretches from central Ohio to
northern Mississippi at 13z...approach from the northwest. The cold
front will move into the western Piedmont later this
afternoon...merging with a prefrontal trough currently over the
western Piedmont...and then cross the area this evening. With very
little deep moisture and MLCAPE less than 500 j/kg (and focused well
over the coastal plain)...there is no additional precipitation expected. As
the band of middle clouds moves east...a south-southwesterly wind
should gust to 20-25kt in the east based on rap soundings with highs
eventually reaching the middle and upper 70s for most areas. -22
Skies will clear behind the front tonight with Post-frontal cold air advection
supporting lows in the upper 40s west to low/middle 50s east.
Short term /Wednesday and Wednesday night/...
as of 240 am Tuesday...
Shortwave energy will continue to rotate through the
region...reinforcing the broad trough in place over the eastern US
on Wednesday. However...this will prove of little consequence with
little to no sensible weather impacts owing to dry precipitable water
airmass(~0.50")in place. Weak/modest dry cold air advection will
continue into late wedneday/Wednesday night as the high builds in
slowly from the west. Highs in the lower 70s northwest to middle 70s southeast. Lows
Long term /Thursday through Monday/...
as of 200 am Tuesday...
The only real thing of interest in the long term forecast will be
the chance of a light frost for some of the Piedmont by either
Sunday or Monday morning when lows May Tank into the middle 30s.
Probabilities are increasing in this occurrence. However... this is
not expected to be a "first freeze" or a killing frost at this time.
Yet... it appears that some of our coldest areas may touch 32 such
as Roxboro. More on this in later forecasts this week.
This is actually the climatological time for the first light frosts
for our region.
Otherwise... it should warm up ahead of the cold front Friday as
highs should reach 70-75 with the SW breeze. Saturday will be breezy
and cool with high 60-65 behind the cold front. It will be "down
right chilly" Sunday with highs expected to hold in the 50s to near
60 southeast. This will set the stage for widespread lows in the 30s Sunday
night/Monday morning under the large Canadian high pressure. By
Monday... highs should rebound back to around 60 with ample sunshine
and light winds.
Aviation /12z Tuesday through Saturday/...
as of 730 am Tuesday...
VFR conditions are expected to continue through the 24 hour taf
period as a mostly dry cold front moves through the area late this
afternoon and evening. Pre-frontal band of showers has fallen apart
east of the mountains
As the front approaches from the west...winds will become breezy
across the area late this morning and into the afternoon...with
sustained southwesterly winds of 10 to 15 knots range... with gusts in the 20 to
25kts range...strongest at eastern terminals (krwi and kfay). Winds
will decouple and will northwesterly behind the front tonight/early
Outlook: another dry cold front will move through the area on
Friday. Otherwise...high pressure will secure VFR conditions
through the period.