Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 242042
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
342 PM EST Fri Feb 24 2017

.SYNOPSIS...
Strong high pressure aloft over the region today will shift east and
offshore overnight in advance of a cold front that will cross the
area on Saturday. Expect near record warmth ahead of the front, with
cooler temperatures on Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 342 PM FRIDAY...

Near record warmth expected again today.

Strong upper ridging will extend from the Gulf of Mexico NE across
the Carolinas and SE Virginia. The surface high pressure will extend
from offshore to over the SE states including NC, with resultant
onset of southerly return flow allowing for an increase in low-level
moisture, evident in an extensive but flat cumulus and stratocumulus
field today, along with an increase in BL dewpoints into the mid to
upper 60s.

The southerly return flow and dry soil conditions will aide in
challenging record high temps for a second consecutive day. Low-
level thicknesses yesterday evening verified at 1380 meters(~50
meters above normal). Thus, with today`s projected thickness of 1300
to 1305, we should match or surpass yesterday`s readings by a few
degrees. Highs 76 to 81, warmest SE.


Tonight... the S-SW wind flow is forecast to begin to increase ahead
of the deepening cyclone pivoting NEwd through the Ohio Valley and
Great Lakes. Associated sfc cold front is expected to reach the
southern Appalachians by daybreak. Strengthening moist WAA in
advance of the front could support an isolated shower across the far
NW zones, otherwise, any rain chances will hold until after 12z
Saturday with the timing of the cold front through the area between
15z to 00z.

The increasing cloud cover and southerly winds will make for a mild
night. Lows in the mid 50s.

&&

.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 342 PM FRIDAY...

Deepening cyclone will lift north into Ontario and Quebec, with
attendant trailing sfc cold front crossing the area Saturday
afternoon/evening. With the better dynamics and deeper moisture
lifting off to the north, accompanying band of convection will
weaken across North Carolinas, with only isolated to scattered
convection skirting across the northern tier.

Temperatures will approach record territory once again, especially
across the south-southeastern tier where it will remain mostly dry.
Highs ranging from mid 70s NW to lower 80s SE. It will be breezy as
well, with sustained winds of 15 to 18 kts, gusting to 25 to 30kts.

As far as severe potential: Steep low-level rates from the
unseasonably strong diurnal heating along with mid-level lapse rates
of 6.8 to 7.50 C/Km will result in weak destabilization of 500 to
1000 J/Kg across central NC. Given impressive 50 to 60kts of
unidirectional shear, it will be possible to see an isolated strong
to severe wind gust across the northern tier.

Strong post-frontal dry cold air advection Friday evening/night
will result in abrupt clearing and seasonable overnight lows
in the lower 30s NW to upper 30s/near 40 SE.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 205 PM Friday...

A broad upper level trough covering most of the contiguous U.S. will
result in a slightly unsettled weather pattern across the U.S. this
period. Temperatures, overall, are expected to remain above or well
above normal through mid-week. Afterwards, lower than normal heights
translates to near or slightly below normal temperatures for the
later half of the work week.

A series of upper disturbances will keep the atmosphere slightly
unsettled across central NC for the beginning of this period. High
pressure building into our region Sunday in the wake of an exiting
s/w and attendant sfc cold front will lead to drier cool conditions
Sunday. This high quickly scoots offshore Monday, leading to an
appreciable warm up with high temps expected to be about 8-10
degrees warmer than Sunday afternoon highs.

Models in general agreement lifting a mid-upper level across the
Deep South  and the Southeast U.S. Monday night into Tuesday,
leading to a chance of showers. At this time, the highest threat for
rain across central NC appears to be late Monday night into early
Tuesday. A more amplified s/w will begin to affect our region
Wednesday with another chance for showers and possibly a few
thunderstorms late Wednesday into Wednesday night. This system exits
our region Thursday morning, leading to a more stable and cooler
period.

Ahead of the mid week system, temperatures will once again average
10-20 degrees above normal with Wednesday`s high temps most likely
in the 75-80 degrees range. Cooler temperatures anticipated Thu-Fri
as a l/w trough develops over the eastern U.S.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
As of 130 PM Friday...

24 Hour TAF Period:  The expansive VFR cu field will dissipate with
loss of heating with south to southeasterly winds of 10kts or less.
A cold front will approach the area from the west late tonight and
is forecast to cross the area between 15z Saturday to 00z Sunday.
With the approach of the front, southerly winds will increase at
KINT and KGSO late tonight between 09 to 12z, which should preclude
fog development across these western TAF sites. However at KRDU,
KRWI and KFAY, winds are expected to remain light, which along with
mostly clear skies could favor the development of sub-VFR ceilings
and visibilities in fog/stratus.

Strong heating and mixing ahead of the front will quickly disperse
any fog or stratus that develops overnight. Expect sustain winds out
of the SW of 15 to 18kts with gusts of 25 to 30kts, strongest in the
east. A broken/weakening band of convection is expected to accompany
the frontal passage through the area Saturday afternoon. With the
better dynamics/forcing and deeper moisture lifting off to the
north, the best chance will lie across the northern terminals. Thus,
a few showers and possibly a thunderstorm or two is possible at KINT
and KGSO between 16 to 20z and at RDU and RWI between 19 to 23z.

Outlook: Strong post-frontal dry cold air advection will lead to a
return to VFR conditions Saturday evening/night, with VFR conditions
continuing through at least Mon as high pressure builds into and
over the region. The chance for sub-VFR conditions and showers and a
few storms will return Mon night into Tue as a warm front shifts
northward through the area.

&&

.CLIMATE...

Record highs for February 24 and 25:

Greensboro:      79 (1982) and 81 (1930).

Raleigh:         81 (1982) and 82 (1930).

Fayetteville:    83 (1930) and 85 (1930).


&&

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

&&

$$

SYNOPSIS...Badgett
NEAR TERM...CBL
SHORT TERM...CBL
LONG TERM...WSS
AVIATION...CBL
CLIMATE...Badgett


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