679
FXUS64 KHUN 031054
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
554 AM CDT Fri May 3 2024

...New AVIATION...

.NEAR TERM...
(Today)
Issued at 433 AM CDT Fri May 3 2024

A mid-level ridge will continue to shift southeastward and off
the Atlantic Coast today, enabling a light (10-20 knot) WSW flow
regime aloft to develop across the TN Valley (between the ridge to
our southeast and a broad mid/upper-level trough to our northwest
that will extend southward into the northern Rockies/Plains). In
the low-levels, light southerly flow currently exists across our
region to the south of a subtle surface trough extending from
central TX east-northeastward through the Arklatex region and into
northwestern TN/southwestern KY. Although dewpoints have
recovered into the l-m 60s in this regime, an even richer tropical
airmass will likely remain confined to the south of a nearly
stationary marine warm front immediately inland from the central
Gulf Coast. The onset of deep-layer warm/moist advection (aided by
a 20-30 knot SSW low-level jet) has resulted in a fairly
widespread coverage of rain and embedded thunderstorms early this
morning (particularly across northwest AL).

Solutions from the 00Z CAMs are in general agreement that this
axis of precipitation will continue to spread slowly eastward
through the mid-morning hours, warranting high POPs region-wide
through 14-15Z. After a temporary minima in the coverage of
precipitation late this morning, additional but more scattered
convection is expected to develop early this afternoon as the
local airmass recovers in the wake of morning rainfall. Highs will
not be quite as warm today (u70s-l80s) due to the impact of
morning clouds and precip, but this should still be sufficient to
produce CAPE on the order of 1500 J/kg, perhaps a bit higher in
the west and a bit lower in the east (based on the lastest HREF).
However, given weak deep-layer flow/shear, storms will be
unorganized, with lightning and locally heavy rainfall the primary
impacts due to PWAT values in the 1.4-1.6 inch range.

&&

.SHORT TERM...
(Tonight through Sunday night)
Issued at 433 AM CDT Fri May 3 2024

Fairly high POPs will remain warranted across the region
overnight, as broad scale vertical motions will increase slightly
with the passage of a weak mid-level shortwave trough to our
northwest. The risk for thunderstorms will remain highest this
evening (prior to the onset of the diurnal cooling cycle), with a
gradual transition to light rain expected by early Saturday
morning. Due to the abundance of moisture in the boundary layer
and only light southerly winds, patchy fog will be possible for
many locations as well.

Present indications are that the general synoptic pattern across
our region will change very little on either Saturday or Sunday,
although with indications of low-amplitude shortwave ridging
across the region on Saturday (in the wake of the shortwave
trough), coverage of afternoon showers and storms will likely be
somewhat lower compared to today. By late Sunday afternoon or
Sunday evening, the marine warm front (discussed in the near term
section) will begin to lift northeastward through the CWFA as a
strong upper low tracking into the central Rockies induces surface
pressure falls across the high Plains of eastern CO/WY. This will
likely support a fairly high coverage of showers and
thunderstorms Sunday evening. Highs will be in the u70s-l80s once
again tomorrow, before warming into the l-m 80s Sunday, and lows
should remain in the l-m 60s through Monday morning.

&&

.LONG TERM...
(Monday through Thursday)
Issued at 433 AM CDT Fri May 3 2024

After warm frontal convection spreads northeastward and out of
the region late Monday morning, the TN Valley will be solidly
within a very warm/moist tropical airmass, with dewpoints expected
to rise into the m-u 60s as southwesterly low-level flow
strengthens. Although this will contribute to greater instability
(especially during the afternoon hours), a mid-level ridge will
shift across the region downstream from the central Rockies upper
low as it begins to spread northeastward into the northern Plains,
and this should yield a lower coverage of mainly afternoon
thunderstorms from Monday-Wednesday. Overnight lows will steadily
increase into the u60s-l70s through the middle of next week (due
to both elevated SW winds and moisture advection), with highs also
warming into the mid (to perhaps upper) 80s by Wednesday.

Although details are unclear at this time range, conditions will
become more favorable for convection at the end of the extended
period (Wednesday night/Thursday), perhaps in the form of MCS
activity that may initiate along a cold front to our northwest and
propagate southeastward into the local area. Should this scenario
materialize, conditions will be favorable for organized severe
thunderstorms across our region, with boundary layer dewpoints in
the u60s-l70s beneath a belt of mid-level WSW flow of 35-45 knots.

&&

.AVIATION...
(12Z TAFS)
Issued at 554 AM CDT Fri May 3 2024

Pockets of rain and embedded TSRA will continue to spread eastward
across the TN Valley this morning, warranting TEMPO groups at both
terminals thru 15Z. After a brief break in precipitation late this
morning, additional showers and thunderstorms will develop this
afternoon within the warm and increasingly humid airmass across
the local area. PROB30 groups have been included for this activity
btwn 20-02Z, as this is the timeframe when AWWs for lightning may
be required. Although the risk for convection will gradually
diminish this evening, light rain and fog may persist across
portions of the area thru the end of the TAF period. Prevailing
sfc winds will remain from the SSW at speeds of 5-10 knots.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.

&&

$$

NEAR TERM...70/DD
SHORT TERM...70/DD
LONG TERM...70/DD
AVIATION...70/DD