537
FXUS62 KRAH 230103
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
903 PM EDT Sat Jun 22 2024

.SYNOPSIS...
A weak mid and upper-level trough will move across the Middle
Atlantic Sunday and Sunday night. A stronger trough and accompanying
surface cold front will move across NC Monday and Monday night. The
front will then weaken and dissipate over the Carolinas through mid-
week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 900 PM Saturday...

No major changes with the evening update. The 00Z upper air analyses
show the 593 dam H5 high over the southern Plains, with central NC
still on the eastern periphery of the high. There is still a bit of
dry air over central NC at H7, but still moist at H85. The 00Z
surface analysis shows a weak trough over the NC Piedmont, between a
high over the NC mountains to the west and Bermuda high to the east.
Surface dewpoints have rebounded a bit back into the upper 60s to
mid 70s, with the exception of a few lingering mid 60s along the VA
border. Still expect lows to bottom out in the low/mid 70s, making
for another muggy night across central NC. There are a few lingering
showers over Anson county as of 9 PM, but those are expected to
dissipate over the next couple of hours. The remainder of the night
should be dry. Still expect development of low stratus again
tonight, mainly across the southeast half of central NC.

&&

.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
As of 250 PM Saturday...

Heights at 500mb will lower by 20-40m on Sunday as a shortwave
crossing the northern US dips into a weakness in the upper ridge,
with an associated cold front approaching the region Sunday night.
Ahead of the front, the remnants of AL92 near Savannah today will
begin to drift north in a further weakened state and become absorbed
into the upper trough, with broad sw-rly flow across the region.
That warm sw-rly flow should offset the slight weakening of the
ridge and keep temps similar to today in the mid 90s.  Soundings
also once again suggest decent mixing and dewpoints in the upper 60s
to lower 70s, which keeps heat indices in the 100-104 range in the
east where heat advisory concerns would be greatest.  Even if a few
sites hit 105, a modest 10kt wind with occasional gusts to 15-20kt
should also keep the heat from feeling overly oppressive, and wet
bulb globe temps remain in mostly in the 84-86 range, suggesting
only a moderate heat threat.  Based on this and coordination with
neighboring offices, we are not issuing a Heat Advisory at this time.

Isolated to widely scattered showers are possible across mainly the
southern coastal plain associated with enhanced seabreeze and
perhaps the weakening AL92 circulation during the afternoon and
evening.  Northern areas are initially capped but with heights aloft
lowering there should be a weakening line of storms associated with
a pre-frontal trough late in the evening.  Poor diurnal timing will
limit any severe threat.  Given how dry forecasting soundings are,
coverage should not be very high in either area., but individual
showers and storms will produce gusty winds with high DCAPE and
inverted V profiles.  Overnight lows will be very muggy in the low
to mid 70s.


&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
As of 330 PM Saturday...

A long stretch of hot temperatures, ~5-10 F above average and in the
90s, will result throughout the forecast period, though seasonable
to seasonably low surface dewpoints/humidity values will
regulate/temper Heat Index values until at least Wed.

A nrn stream shortwave trough/compact closed cyclone now centered
over srn Saskatchewan will amplify modestly while progressing sewd
and across the Great Lakes through this weekend, then across and
offshore the Middle Atlantic Mon-Mon night. Glancing and weak (10-20
m/12 hr) mid-level height falls, and the passage of a surface cold
front, will result over cntl and ern on Mon. Scattered convection
will accompany the front, with the relative greatest concentration
from the Coastal Plain to the coast.

Shortwave ridging and marked mid-level drying and warming will
follow and expand across the srn Appalachians and Carolinas Tue-Tue
night, during which time weak high pressure and dry but still hot
conditions will build across the srn Middle Atlantic.

A couple of additional shortwave perturbations are otherwise
forecast to migrate ewd and across the Canada/US international
border and Great Lakes mid-late week and support an associated weak
cold frontal passage across the srn Middle Atlantic late Thu-early
Fri. Low-level moisture/humidity will increase ahead of the front
and favor a renewed, ~30-50% chance of diurnal convection Wed and
especially Thu.

A broad and strong mid-level high/ridge will then restrengthen from
the srn Plains and Southeast to the w-cntl Atlantic through next
weekend. A related surface high will expand from the cntl Atlantic,
near and east of Bermuda, wwd and across the South Atlantic states,
while an Appalachian-lee trough will extend across the srn Middle
Atlantic Foothills/wrn Piedmont. The presence of the ridge and
warming aloft should tend to keep the chance of diurnal convection
near or slightly below climo probabilities (~20-30%).

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
As of 714 PM Saturday...

Through 00Z Monday: The primary aviation concern through the
24 hour TAF period will be the chance for a period of low-MVFR or
IFR cigs mainly along and south of a line from KIXA-KRDU-KVUJ
between 08z-13Z Sunday. Otherwise, VFR conditions are expected with
S to SW winds generally around 10kt, with a few higher gusts to 15-
20kt after 13Z Sunday.

After 00Z Monday:  An approaching cold front will support a
slight chance of showers and storms and related sub-VFR restrictions
late Sunday, with better coverage on Monday. Tuesday should be
mostly dry before isolated showers and storms may return on
Wednesday especially west.

&&

.CLIMATE...

Record High Temperatures:

June 22:
KRDU: 100/2022
KFAY: 101/2022

June 23:
KRDU: 100/1986

June 24:
KRDU: 99/2010
KFAY: 102/1914

June 25:
KRDU: 100/1952
KFAY: 102/1914

June 26:
KRDU: 102/1952
KFAY: 101/1951

June 27:
KFAY: 102/1998


Record High Minimum Temperatures:

June 22:
KRDU: 78/1933

June 23:
KGSO: 74/2015
KRDU: 77/1890
KFAY: 77/2017

June 24:
KGSO: 76/2015
KRDU: 76/1888
KFAY: 79/2010

June 25:
KFAY: 75/1952

June 26:
KGSO: 74/2010
KRDU: 76/1902
KFAY: 76/1997

June 27:
KGSO: 76/1969
KRDU: 76/1952
KFAY: 77/1998

June 28:
KGSO: 76/1969
KRDU: 76/1952
KFAY: 78/1914

&&

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

&&

$$
SYNOPSIS...MWS
NEAR TERM...KC
SHORT TERM...bls
LONG TERM...MWS
AVIATION...pwb/np
CLIMATE...RAH