National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 181932
AFDRAH

AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
330 PM EDT Thu Jul 18 2019

.SYNOPSIS...
An upper level disturbance will slowly cross the area today, before
settling across southeast North Carolina tonight. A strong ridge of
high pressure will build over the Mid Atlantic region from Friday
through the weekend, bringing dangerous heat. A pattern change to
cooler weather will arrive next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 250 PM Thursday...

Scattered storms have already sprung up over western and north-
central NC, translating cyclonically eastward following the mid
level steering flow associated with the incoming weak shortwave
trough. The latest surface analysis continues to feature a weak
trough through the Piedmont. MLCAPE has already risen to 1500-2000
J/kg with D-CAPE of 900-1200 J/kg and low level lapse rates of 7.5-
8.0, all just slightly lower than yesterday`s values, but still
supportive of scattered strong storms with downburst potential well
into this evening, particularly given additional large scale forcing
for ascent provided by the mid level wave, despite the poor deep
layer shear. Will have high chance to low likely pops spreading W to
E through the evening, with a gradual NW to SE downturn overnight as
a subtle vorticity lobe shifts to our E. Based on this morning`s
temps and statistical guidance, will have lows in the mid-upper 70s
except lower 70s NW. -GIH

&&

.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
As of 330 PM Thursday...

Another dangerously hot day. The heat advisory will be maintained
for the Coastal Plain and eastern Piedmont/Sandhills counties for
Fri for heat indices of 102-107.

The shortwave trough will weaken further as it shifts slowly to our
E, while the surface trough holds over the CWA. As the high PW (>2")
shifts into our SE half, the better convection chances should follow
suit, and with MLCAPE peaking at 2000-2500 J/kg in this same area,
will retain good chance pops in the E and S, peaking in the mid
afternoon through early evening, before tapering down in the far SE
overnight. Once again, the poor deep layer shear will limit storm
organization and maintenance despite the potential for vigorous
updrafts. Little change in the overall thermal profile is expected,
with 850 mb temps still hovering near 19C, and surface dewpoints
should remain solidly in the 70s. As such, the earlier issued heat
advisory, an areal expansion from today`s, will be maintained. Given
these successive days of hot weather with little recovery at night,
the heat illness risk will be on the rise, even if peak HI values
hold under 105F. Highs in the mid-upper 90s and lows 73-78. -GIH

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 320 PM Thursday...

...Excessive Heat Watch 11 AM Saturday through 11 PM Sunday evening
for the eastern Piedmont, Sandhills, and Coastal Plain...

More of the same as far as the heat is concerned for at least the
first half of the long term forecast as the strong upper ridge
remains anchored in place over the southeastern CONUS that will keep
afternoon highs well into the 90s through Monday. Heat will reach
potentially dangerous levels on over the weekend as heat index
values could reach values higher then 110 degrees across the eastern
half of the forecast area both Saturday and Sunday afternoons with
heat indices in the western half of the CWA between 105-110 degrees.
As such, an excessive heat watch is in effect from 11 AM on Saturday
through 11 PM on Sunday. Everyone needs to take proper precautions
if outside this weekend.

There is an end in sight however to the oppressive heat as a very
strong cold front will move southward through the mid-Atlantic
states Monday and into the Carolinas on Tuesday, aided by a
deepening upper level trough coming out of eastern Canada. Not only
will this extinguish the extreme heat but also provide some quality
rain chances as early as Monday evening for the Triad and through
the day on Tuesday for the entire forecast area. As the front sinks
south it will begin to slow and therefore a good amount of the area
could see upwards of 2 inches of rain with the system with some
localized areas, particularly in the southeast coming in with
slightly higher values through Wednesday as the front hangs up along
the coast. As far as post frontal temperatures are concerned,
Tuesday afternoon highs should remain in the 80s across the board
with low 80s north and high 80s to near 90 degrees in the south. By
Wednesday afternoon, the cooler airmass continues to move in with
highs generally in the low to mid 80s across the board.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
As of 115 PM Wednesday...

VFR conditions will dominate for the next 24 hours, outside of
scattered showers and storms, which could bring a short period
(likely under 1 hr in duration) of sub-VFR cigs/vsbys in rain. Gusts
up to 40 mph may occur both in and near storms, including outflows
that may spread well away from storms. The storm threat will peak
late this afternoon through late evening, although southeast
sections including FAY will see a storm threat lasting through
around 08z. Isolated patches of MVFR or high-end IFR fog may form
late tonight/early Wed morning near or over bodies of water, but
these should not be widespread. Toward the end of the TAF valid
period, after 16z, scattered storms may begin to develop near FAY.
Winds will generally be from the SW around 5-10 kts with some gusts
to around 12-15 kts the rest of this afternoon, then light/variable
into Fri morning with a veer to the W and NW.

Looking beyond 18z Fri, there is a good chance of late day storms
Fri afternoon/night in the SE, especially 21z-06z. Shower/storm
chances will decrease over the weekend, with a return to mostly dry
and hot conditions for Sat-Mon, although storm chances will start to
creep back up by late Mon and remain high through Tue. With isolated
exceptions, the risk for early-morning sub-VFR fog/clouds through
this period is generally low. -GIH

&&

.CLIMATE...

Record high temperatures and years for the next few days.


              RDU        GSO        FAY
Thu 7/18   103/1887    97/1986   103/1942
Fri 7/19   101/1902    98/1977   101/2002
Sat 7/20   102/1942   100/1977   104/1932
Sun 7/21   102/2011   102/1926   105/1937
Mon 7/22   103/2011   101/1926   107/1932

&&

.RAH WATCHES/WARNINGS/ADVISORIES...Corrected.

Heat Advisory until 7 PM EDT this evening for NCZ011-
026>028-041>043-077-078-085-086-088-089.

Heat Advisory from noon to 7 PM EDT Friday for NCZ007>011-024>028-
040>043-075>078-085-086-088-089.

Excessive Heat Watch from 11 AM EDT Saturday through 11 PM Sunday
evening for NCZ007>011-024>028-040>043-075>078-085-086-088-089.

&&

$$
SYNOPSIS...Hartfield
NEAR TERM...Hartfield
SHORT TERM...Hartfield
LONG TERM...Ellis
AVIATION...Hartfield
CLIMATE...CC