Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 201037
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
640 AM EDT Fri Apr 20 2018

.SYNOPSIS...
Chilly high pressure will build south over the region tonight
through the weekend. Low pressure is forecast to track east across
the Gulf Coast states this weekend, then turn up the eastern
seaboard early next week. This will bring unseasonably cool and wet
conditions early to mid next week.
&&

.NEAR TERM /TONIGHT/...
As of 245 AM Friday...

...Frost Advisory 400 AM through 900 AM for all but the SE...

1035+ mb cold surface high pressure was located over the upper
Midwest early this morning. CAA will continue this morning, then the
pressure gradient is forecast to relax this afternoon. This will
lead to much, much lighter winds today. Very dry air will also be in
place today. We expect sunny skies and light north winds at 5-10
mph. Highs will only be able to reach the lower 60s NE ranging into
the mid 60s SW, or about 10-12 degrees below normal.

A frost advisory was considered again tonight. However, the trends
in the statistical guidance have been a bit upward, now indicating
35-40 may be more likely than lower to mid 30s. If this trend
continues, we may escape widespread frost concerns tonight. We will
hold off on an Advisory for now and evaluate again late morning or
early afternoon. It appears that the culprit in the slightly higher
temperatures with the statistical guidance may be related to the
expected weak reinforcing cold front that should push south into the
area this evening. This would generate mixing, slowing the cooling
process. This is depicted best by the forecast increase in surface
pressures by 5+ mb between 06z and 12z/Saturday. Statistical
guidance is forecasting a bump in dew points into the 30s overnight
with a more ENE flow. Given these trends, we will continue the
forecast of clear tonight with lows in the 35-40 range. Any frost
should be scattered and confined to the low lying areas where cold
air drainage is common.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 245 AM Friday...

The chilly high pressure center is forecast to drift off the VA/NC
coast late Saturday with another reinforcing high expected to follow
Saturday night. Expect only a few jet related cirrus at times,
mainly Saturday night. Highs Saturday with light winds should be in
the 65-70 range. Lows Saturday night creep up just a bit into the
upper 30s to mid 40s.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 355 AM Friday...

Surface high pressure will extend into the area from the north and
northeast on Sunday, with dry weather expected as weak s/w ridging
holds over the area. Temps will continue to run below normal on
Sunday, with highs generally in the upper 60s/near 70.

Meanwhile, a mid/upper level area of low pressure will approach the
region from the west over the weekend and move into the TN Valley
and Southeast U.S. by early next week, helping to spread precip into
central NC by early next week, with a damming air mass developing.
This will lead to below normal high temps in the 50s and 60s on
Monday and Tuesday, with lows in the 40s and 50s.

The latest GFS and ECMWF have trended more inland with an
associated surface low tracking across the region on Tuesday
evening/Tuesday night, possibly resulting in a chance for some
thunderstorms. The initial surface low will lift to the north of the
area on Wednesday as the lead s/w trough pivots through the area.
However, additional energy is forecast to approach/move through the
area on Wednesday night in Thursday, Thus, will maintain a slight
chance of showers in the forecast for Wednesday night into Thursday.
High temps mid week are expected to recover some, with highs in
the upper 60s to 70s, with lows in the 50s

&&

.AVIATION /12Z FRIDAY THROUGH WEDNESDAY/...
As of 645 AM Friday...

24-Hour TAF Period: High confidence VFR conditions will prevail
through Saturday.

Looking ahead: Expect VFR conditions to persist through the weekend.
A storm system is forecast to bring IFR CIGS and VSBYS with rain and
fog late Monday or Monday night into Wednesday morning.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 4 AM to 9 AM EDT Friday for NCZ007>011-
021>028-038>043-073>076-083-084.

&&

$$
SYNOPSIS...Badgett
NEAR TERM...Badgett
SHORT TERM...Badgett
LONG TERM...BSD
AVIATION...Badgett


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