Turner Downs Forecast Discussion

000
FXUS62 KRAH 291126
AFDRAH

AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
625 AM EST Mon Nov 29 2021

.SYNOPSIS...
A dry cold front moving through the region will push off the
Southeast coast this morning. High pressure will build into the
Gulf and Southeast states from the west through mid week.

&&

.NEAR TERM /TODAY AND TONIGHT/...
As of 150 AM Monday...

Dry weather will hold through tonight, with periods of mid and high
clouds, most notably over the W Piedmont through the predawn hours
this morning. As expected, the dry cold front, marked by a wind
shift to NW and falling dewpoints, has moved through the NW CWA
(although it was preceded by a more gradual shift of winds to W
associated with a prefrontal trough). A few initial gusts are
expected early this morning within the density current as cooler air
rushes in post-front, but the more substantially brisk and gusty NW
winds will arrive with the deepening mixed layer by mid morning, as
the 25-30 kt winds through the 1000-3000 ft depth mix groundward.
Sustained speeds and gusts should dwindle by mid afternoon as the
jetting just aloft exits to our E with a decreasing MSLP gradient
over NC. Overall cloudiness should be most pronounced early this
morning, already evident on satellite imagery as a batch of high
level moisture and 80+ kt mid level jet moving over the central/S
Appalachians generates orographically enhanced clouds in the lee.
This moisture will decrease later this morning as the jetlet heads
E, so expect the rest of the day to be mostly sunny, except for
occasional mid and high clouds advecting in within the slightly
perturbed but largely flat NW steering flow into the area. Projected
thicknesses 25-30 m below normal support cool highs in the upper 40s
to mid 50s. Despite the cool temps, low humidity dropping to 20-35%
combined with the gusty winds and dry tree litter will produce an
increased danger of adverse fire behavior today.

Fair to mostly clear skies are likely to hold through this evening,
however a shot of mid level moisture currently over the Upper
Midwest is poised to dive through the region after midnight,
bringing a potential scattered to broken mid cloud deck overnight.
Expect chilly temps bottoming out at 23-32. -GIH

&&

.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
As of 215 AM Monday...

Continued dry. The expected mid level cloudiness should be exiting
the Mid Atlantic coast Tue morning, resulting in mostly sunny skies
for much of the day as high pressure continues to build eastward
over the Gulf states and Southeast. This W-E surface ridge settling
to our S will result in a cessation of CAA as surface flow shifts
back to southwesterly, pushing thicknesses back up closer to normal
and suggesting highs in the mid 50s to lower 60s, several degrees
higher than today but still a bit below normal.

Models show our next batch of mid level moisture, now pushing ashore
in the PacNW, diving SE through the Ohio Valley into the Mid
Atlantic late Tue night, so we should see an increase in clouds from
the NW overnight. Expect milder lows, mostly low-mid 30s. -GIH

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 153 AM Monday...

Synoptic features through the end of the work week will be hard to
find as mid/upper level flow will be out of the west-northwest
Wednesday through Friday. Some passing clouds are expected Wednesday
and Thursday with sunny skies on Friday. The GFS and European have
struggled the last few days with having any agreement for the
pattern over the weekend, and those differences continue now.
Watching the two deterministic models alternate between depicting
high and low pressure in the same region does very little for having
any confidence to add rain to the forecast. However, the GFS and
European do show agreement that there could be rain moving in by
Monday the 6th, just outside of the official forecast period.

Temperatures will be above normal through much of the period, with
temperatures peaking in the upper 60s and lower 70s on Friday,
between 10-15 degrees above normal. Uncertainty with temperatures
increases with the uncertain synoptic pattern for the weekend - at
this point highs look a few degrees cooler on Saturday and values
should return to near normal on Sunday with northerly winds.
Overnight lows will be in the 30s and 40s.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
As of 625 AM Monday...

VFR conditions are expected at all terminals through the TAF period.
As of 11Z, the dry cold front has made it through INT/GSO, primarily
noticeable by slightly lower dewpoints. Skies should quickly clear
at INT/GSO, while high clouds make their way across other sites
through mid-morning. There will likely be a brief lull in gusts, and
made little change to this in the 12Z TAF package. Gusts should come
to an end around 21Z-22Z with sunset, then become light and back
from the northwest to southwest overnight less than 5 kt.

Looking beyond 12z Tue, VFR conditions will hold through Fri.
Periods of mid and high clouds are expected through the week as high-
level disturbances move through in NW flow aloft, within a dry air
mass under surface high pressure. -GIH

&&

.FIRE WEATHER...
As of 215 AM Monday...

The combination of brisk northwest winds gusting to around 20 mph,
falling humidity into the 20% to 35% range, recent dry weather, and
an abundance of leaves and other tree litter will bring about a risk
for adverse fire behavior today.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SYNOPSIS...BSD/np/GIH
NEAR TERM...Hartfield
SHORT TERM...Hartfield
LONG TERM...Green
AVIATION...Green/Hartfield

NWS RAH Office Area Forecast Discussion