406
FXUS62 KRAH 261830
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
230 PM EDT Sat Apr 26 2025

.SYNOPSIS...
A cold front will move across the Middle Atlantic late this evening
with Canadian high pressure building into the region through Monday.
High pressure shifts offshore Tuesday and brings unseasonably warm
conditions Wednesday through Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 200 PM Friday...

* Level 1 out of 5 risk for strong to severe straight-line winds
  this afternoon into the early evening.

Regional radar and satellite imagery shows showers over the
Northwest Piedmont are beginning to gradually deepen evident by
glaciation and rising echo tops. These showers have developed in a
narrow swath of 500 MLCAPE, according to SPC Mesoanalysis, which is
expected to increase to 500-1000 J/kg across all of central NC
through this afternoon. However, it is unlikely that these storms
will realize this amount of instability as they will be constantly
fighting against abundant dry air entrainment and gradually mid-
level height rises. This should keep coverage isolated to scattered
through much of the afternoon and mainly a pulse to multicell storm
mode due to deep-layer shear of 20 to 25 kts.

Mostly shallow convection will continue to propagate east-southeast
along the eastward progressing trough axis and effective outflow
through a majority of central NC this afternoon into the evening
hours. If isolated deep convection is able to occur, low-level lapse
rates approaching 8-9C/km and DCAPE of 500-800 J/kg may support
isolated strong to severe wind gusts. Large hail may be difficult to
achieve with marginal instability and multicell storm mode, but
isolated sub-severe hail (<1") could be possible from the deepest
updrafts.

Cooler and drier air will filter in behind the cold front tonight
with some briefly gusty northwest to northerly winds immediately
behind the front. Lows tonight should be cooler and settle generally
in the 50s.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 155 PM Sunday...

* Dry weather and a return to near or slightly below seasonable
  temperatures on Sunday and Monday.

The short term period will be dominated by a northwest flow aloft
along with cool and dry surface high pressure that will extend into
our region. The mid and upper level flow will be somewhat
enhanced and turn northwesterly behind the mid and upper level
trough moving off the coast early Sunday and weaken as it becomes
more northerly ahead of a narrow but somewhat amplified ridge that
moves east from the Midwest early Sunday and folds over into the
eastern Great Lakes and OH Valley on Monday night. A 1029 mb surface
high will be centered over the southern Great Lakes on Sunday
morning and then shift southeast into the mid Atlantic on Monday
morning before moving off the coast on Monday night. This airmass
will be characterized by low level thickness values across central
NC in the 1335-1355m range on Sunday morning and with PW values
Sunday afternoon below a half inch which is about 35% of normal. The
airmass should be similar but slightly modified on Monday.

The sensible weather on Sunday will feature sunshine mixed with some
high clouds and a light north wind. Highs will range from around 70
to 75 with perhaps a few upper 60s near the VA border and near
Roanoke Rapids. These highs are generally 1 to 5 degrees below
average. Skies will largely clear on Sunday night with good
radiational cooling conditions. Nudged lows below the NBM guidance
by 2 to 4 degrees with lows in the mid 40s to around 50 on Monday
morning. Mainly sunny skies are expected on Monday with highs in the
mid and upper 70s. Lows Monday night will range in the upper 40s to
lower 50s. -Blaes
&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 230 PM Saturday...

* Temperatures moderating to well above normal for Wednesday through
  Friday.
* Dry weather on Tuesday will give way to a threat of widely
  scattered convection on Wednesday and especially Thursday with the
  greatest threat of storms, some of which could be strong, on
  Friday.

A mid and upper level ridge will extend from the northern Gulf
northeast into the mid-Atlantic on Tuesday morning. With the
ridge axis overhead, some high cloudiness will begin spreading
into the Carolinas from the west. As heights increase and surface
high pressure moving off the coast, temperatures will warm on
Tuesday with highs in the lower to mid 80s.

A west to east oriented cold front will drop south into the mid-
Atlantic late Wednesday with a southerly to southwesterly low level
flow persisting ahead of the front across the Carolinas . As
the front approaches, a few showers and possibly a thunderstorm
are possible, favored across the north and northwest and during
the afternoon and evening. Highs on Wednesday will range in the
mid to upper 80s.

While some of the guidance suggests that the front across the mid-
Atlantic could drop into NC late Wednesday and Thursday, past
experience suggests this may be hard to do. A stronger front,
supported by a mid and upper level trough, will approach the region
from the west on Thursday and likely move across the Carolinas on
Friday. While the mid and upper level trough is weakening, it is
associated with 35 to 45 kts of mid level flow and PW values in
excess of 1.25 inches or 140% of normal. This will likely result in
scattered, mainly afternoon and evening, showers and storms on
Thursday and Friday with the best chance on Friday which is also
when there is the greatest chance of a strong storm. Temperatures
will remain well above normal with highs on Wednesday through Friday
in the mid to upper 80s with a few spots touching 90. These highs are
around 10 to 15 degrees above average.

Guidance varies, but there is a signal that the front and trough
will be east of central NC on Saturday which would support cooler
temperatures and and drier conditions. Went with highs in the mid
70s to around 80. -Blaes

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
As of 120 PM Saturday...

Mostly scattered showers and isolated thunderstorms are beginning to
develop across south-central VA and northwest NC. This activity is
expected to gradually deepen while drifting southeast through
central NC. Erratic gusty winds, MVFR to IFR vsby, and cloud-to-
ground lightning will be the main threats to direct terminal
impacts. Although coverage will mostly be scattered, TEMPOs and
PROB30s have been kept in the 18z TAFs and tweaked to most likely
timing for showers/storms in the vicinity of the terminals. Gusty
southwest winds will turn northwest to northerly with the passage of
a cold front. Continued gusty winds behind the front of 15 to 25 kts
will be possible for a few hours before gradually relaxing.

Looking beyond 18z Sunday, after an extended period of dry VFR
conditions, a threat for mainly diurnally driven showers/storms
returns as early as Wed with better chances on Thurs.

&&

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

&&

$$

SYNOPSIS...Swiggett
NEAR TERM...Swiggett
SHORT TERM...Blaes
LONG TERM...Blaes
AVIATION...Swiggett