Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC-- Highlight Changed Discussion --
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FXUS62 KRAH 271731
Area Forecast Discussion
National Weather Service Raleigh NC
130 PM EDT WED JUL 27 2016
Strong high pressure aloft will extend across the region through
Thursday, bringing continued hot and humid conditions to central NC.
The chance for afternoon storms will increase toward the weekend.
.NEAR TERM /Through THursday/...
As of 1112 AM Wednesday...
Today: Persistent mid/upper level anticyclone located just to the
south/southeast of central NC will continue to provide the region
with hot and humid conditions with another day of afternoon temps in
the mid to upper 90s and heat index values in the 103-109 degree
range (highest east and south again). Given the consecutive days of
heat index values of around 100/low 100s across the northwest
piedmont and warm overnight lows have decided to expand the heat
advisory to encompass the entire area.
Strong surface heating within the high PW air mass in place will
support isolated to scattered convection this afternoon, though the
remnant outflow boundary from last night`s convection could lead to
convective initiation. Proximity to the modest 30kt mid-level flow
over the Mid-Atlantic states, on the northern periphery the upper
anticyclone, could support a few severe clusters, especially across
the northern half of the forecast area. The primary threat again
will be locally damaging wind gusts. Given PW`s around 2 inches+
heavy rain will be possible, with a threat of localized flooding if
any clusters slowly track across an urban area.
Tonight: Most convection will generally die off by late evening with
another warm night expected. Expect lows temps tonight to generally
be in the mid to upper 70s. Can`t completely rule out additional
weak disturbance tracking across northern portions of the area
overnight, possibly sparking a shower or storm, though think any
activity will be quite isolated as we should still be under the
general influence from the nearby mid/upper level ridge.
Thursday: The persistent mid/upper level ridge will again provide
central NC with another hot and humid day for Thursday, with a the
main threat of storms across the northern half of the area again.
Additional strong to severe storms will be possible in the late
afternoon/evening, with the main threat again from locally damaging
wind gusts along with a localized flooding threat (mainly urban
areas) and dangerous cloud to ground lightning. Expect high temps
will gain be in the mid to upper 90s, with similar heat index values
and likely another heat advisory.
.SHORT TERM /Thursday night and Friday/...
As of 325 AM Wednesday...
Model guidance in good agreement in their depiction of a s/w lifting
newd from the TN valley Thursday night, and into the Mid Atlantic
Friday. This feature will aid to enhance low level confluence along
a surface trough across the NC Piedmont, and lead to a decent chance
for scattered convection, especially during max heating Friday
afternoon. May see a few showers/t-storms late Thu night in
vicinity of the NW Piedmont.
Max temps Friday dependent upon extent of morning cloudiness and
when convection erupts. Currently favor max temps lower 90s nw to
the mid/upper 90s east and south. This suggest a possible
continuation of advisories for heat along the i-95 corridor.
Remaining very warm and muggy overnight with temps in the mid-upper
.LONG TERM /Friday night through Tuesday/...
As of 325 AM Wednesday...
The lead s/w will lead to an eventual shift in the upper air
pattern, with a suppression of the upper ridge, and the development
of an upper trough, extending from New England into the Carolinas.
During this transition, expect a series of s/ws to cross through our
region, sparking scattered convection. Difficult this far out to
pinpoint a particular time when convective coverage will be
greatest, though current indicators point toward the end of the
weekend into early next week. For now, will refrain from likely
PoPs, and cap PoPs at high chance. Potential for locally excessive
rainfall to occur by late in the weekend or early next week as deep
sw flow develops, suggesting potential for storms to train
repeatedly across the same location.
Since expecting more clouds and scattered convection, and upper
ridge being suppressed well to our south, should see a trend of max
temps returning to near normal levels. Thus expect max temps to
trend from the low-mid 90s Saturday to the upper 80s/lower 90s early
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --As of 130 PM Wednesday...
Isolated to scattered convection could impact any of the terminals
this afternoon and evening. A brief period of Sub-VFR conditions
will be possible with the stronger storms, along with gusty winds.
Convection should begin to wane aoa 03z, with generally dry
conditions overnight. Patchy sub-VFR fog and/or stratus will be
possible again on Thursday morning, especially near locations that
receive heavy rain.
Outlook: Outside of isolated to scattered storms each
afternoon/evening and some patchy early morning fog, expect
predominately VFR conditions through Friday. Rain chances are
expected to increase by the weekend and into early next week.
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Heat Advisory from noon today to 8 PM EDT this evening for