Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 221826

Area Forecast Discussion
National Weather Service Raleigh NC
225 PM EDT SAT OCT 22 2016

High pressure will bring much cooler and drier air to the region through
the weekend. Another cold front is forecast to move through the state
Monday, bringing additional cool and dry air.


As of 215 PM Saturday...

Cold advection will weaken this evening and wind gusts will diminish tonight
as high pressure over the Lower Mississippi Valley build across the
Southeast.  Radiational cooling, while not optimal given a little
bit of a pressure gradient over the area, should still be good under
clear skies.  Some concern for orographic cirrus again, but there
may not be enough ambient moisture from upstream. This past
mornning`s low level thickness at GSO was 1334m, which should yield
lows int eh upper 30s to lower 40s under average radiational
cooling, though some mid 30s are very possible over the western
Piedmont where winds will be lightest. Have undercut guidance in
this area. No Frost Advisory seems needed given decoupling
uncertainty and the resulting short duration of frosty temps.


As of 215 PM Saturday...

West-northwesterly flow, 20-30kt at 850mb, ahead of a frontal zone
dropping backdoor into the Mid-Atlantic States, will result in warmer
temps on Sunday.  Guidance seems a little too cool based on dry
adiabatic mixing between 925mb and 850mb, though the trend in guidance
has been slowly upward in the past few runs.  Expect highs of 68-
72.  Not as cold on Sunday night with a light wind, 45-49


As of 225 PM Saturday...

An upper level trough will exit the east coast early this week and a
dry cold font will pass through Monday night leaving central NC on
the front side of an upper level ridge. This will keep temperatures
warm on Monday with highs in the mid 70s but that will quickly
change as surface high pressure builds out of Canada keeping
conditions cool and dry with highs topping out in the 60s on Tuesday
and Wednesday. Northwesterly flow could be breezy at times during
the first couple days of the work week but gusts should top out
around 15-20 mph but not much higher. The coolest night during this
period would be Tuesday night when temperatures drop into the low
40s but frost should not be a threat.

The ridge axis moves through by Thursday morning and a warming trend
will ensue for the end of the week with the main weather feature
being a low pressure system moving through the Great Lakes region
which is accompanied by a deepening upper trough and a surface cold
front that will approach the Carolinas late in the week. Model
solutions differ on the timing and impacts at this time so will
carry slight chance pops starting Thursday through Friday. Highs
during this period will climb back into the low 70s with lows in the
lower 50s.


As of 200 PM Saturday...

High confidence in VFR conditions through the TAF period, with gust
northwest winds today, sustained 10-15kt and gusting to 20-30kt.
Winds will die off by 00Z this evening, and then become more
westerly on Sunday, gusting to 15-20kt mainly at INT and GSO.

Looking Ahead:  VFR conditions are expected to continue through at
least midweek, with increasing chances of sub-VFR ceilings late next

Of note: Forecast soundings show the potential for LLWS Sunday
night, with a strong decoulping inversion at the surface and 20-30kt
wind at or just below 2000ft.




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